ANS 415 Exam 2

Phosphorus functions

- Is part of the bone matrix - Is part of the nucleoproteins, phospholipids, and nucleic acids (important in the growth) - Participation in acid-basic intracellular homeostasis - Part and activation of the coenzymes (NAD, and NADP) - Is extremely necessary in the metabolism and growth of rumen bacteria (Celluloliticas)

Metabolic Disorders

A number of metabolic disorders have their basis in disturbances in energy metabolism. • These include: - diabetes, - metabolic syndrome, - ketosis. Besides these, other aspects of energy metabolism, include metabolic events in: - obesity, - longevity

What are ADF and NDF in forages?

ADF is a measure of the plant components in forages that are the least digestible by livestock, including cellulose and lignin. ADF increases digestibility decreases, so forages with high ADF concentrations are typically lower in energy. A plant's structural components are the source of NDF, specifically the cell walls. NDF relates to free-choice by livestock because it provides lowcalorie filler. You generally want to choose forages with low NDF percentages because these levels increase as forages mature.

Selenium Importance

Antioxidant action, participation in the selenium proteins • In animal production, the use of Organic selenium (seleniomethionine) reduce the mortality, improve feed efficiency, meat and milk quality. • Selenium is a key nutrient in animal nutrition and is crucial for an optimal antioxidant status and immune function.

Macro-Minerals:

Are required in relative large quantities; Calcium, Phosphorus and Magnesium are major components of the skeletal system, and thus function in a structural role. Macro-Minerals: exceeds 100mg daily Calcium, Phosphorus, Magnesium, Sodium, Potassium, Chlorine, Sulfur

Which one alternative below, in the past was referred to as a "Fertility Vitamin"?

Ascorbic Acid

Water soluble vitamin deficiencies

B6 - dermatitis, skin disorders, kidney stones, nausea, cracks at the corners of mouth B7 - nausea, vomiting, muscle pains, anemia, fatigue, loss of appetite, heart abnormalities B9 - deficiency of folic acid causes birth defects, anemia, diarrhea B12 - fatigue, anemia, neurological disorders, bone marrow C - improper healing of wounds, loose teeth, bleeding and swollen gums, muscle weakness

The mineral Selenium and Vitamin E, plays an important role in the immune response defense in the immunological system to protect the animal against a pathogen. Whats is the most activity action of this Mineral and Vitamin?

Both have a very good antioxidant activity in the tissues

Calcium

Calcium is the most common mineral in the human body and essential for many metabolic processes • Increasingly, calcium is being found to be involved in processes of energy metabolism as well. • For example, calcium activates a regulatory protein, calmodulin, which activates ion channels and numerous enzymes.

The Glycaemic / Glycemic Index

Carbohydrates that are digested slowly and release glucose gradually may produce metabolic effects that are different from dietary carbohydrates which are digested rapidly. • The glycaemic index measures the blood glucose response to a fixed amount of dietary carbohydrate compared to the same amount of a standard carbohydrate source, and thus measures the blood-glucoseraising potential of foods. • The blood-glucose area under the curve in a glucose tolerance test is expressed as a percentage of the standard. • The chemical nature of carbohydrates includes: - Type of monosaccharide (fructose and galactose have a lower glycaemic index than glucose), - Type of starch (amylopectin is digested more rapidly than amylose), - Presence of viscous non-starch polysaccharides (gums, Bglucans) which because of their viscosity reduce the rate of glucose absorption. - Foods with an intact botanical structure (whole grains) are digested more slowly than those with processed, gelatinized starch. • Cooking, processing and refining all tend to increase the glycaemic index.

Which one is called a "Sunshine Vitamin"?

Cholecalciferol

Cholesterol Metabolism

Cholesterol is present either as free cholesterol or combined with a long chain fatty acid (LCFA) as cholesterol ester. • In plasma, both forms are transported with lipoproteins. • Cholesterol is amphipathic, meaning that it has both polar and non-polar properties, and thus is soluble in both water and lipid. • Because of this property, it is a constituent of cell membranes and the outer layer of lipoproteins. • All carbon atoms in cholesterol are derived from acetyl CoA. • It is synthesized in many tissues, particularly the liver, and is the precursor of all other steroids in the body (vitamin D, bile acids, androgens, oestrogens, corticosteroids). Cholesterol in the body is derived from both dietary sources and de novo synthesis in the liver and other tissues.

Magnesium Importance

Correlated with calcium and Phosphorus, in the metabolism and distribution in the body. • Participation in the metabolism of carbohydrates, and lipids.

bomb calorimeter.

Determines the caloric content of biological materials • In brief, the sample is burned in a combustion chamber (bomb) inserted in a vessel containing a known weight of water. • As the sample burns, it releases heat, which is taken up by the water. • From the weight of the sample, weight of the water, and rise in temperature of the water, the number of calories of heat energy released can be calculated. • When a feed sample is burned in a bomb calorimeter, its gross energy is determined. • To determine the fraction of the gross energy that the animal can actually utilize, a metabolism trial must be conducted to account for various losses, yielding values for digestible, metabolizable and net energy: Digestible energy (DE) = Gross energy (GE) - Faecal energy. Metabolizable energy (ME) = DE - (Urinary energy + Rumen gas losses). Net energy (NE) = ME - Heat loss

Laminitis

Inflammation of the laminae of the foot - the soft tissue structures that attach the coffin or pedal bone of the foot to the hoof wall. The inflammation and damage to the laminae causes extreme pain and leads to instability of the coffin bone in the hoof.

innate vs adaptive immunity

Innate / Natural Immunity (non-specific responses) 1st line - skin, mucous membranes and secretions, normal flora 2nd line - innate immune cells, inflammation, complement, antimicrobial substances Adaptive / Acquired Immunity (specific Responses) 3rd line - Specialized lymphocytes - B cells (produce antibodies), T cells - Helper T cells and Killer T cells

Ketosis

Ketosis is a metabolic disease, in which excessive quantities of ketone bodies are produced. • It commonly occurs in starvation when body lipid is mobilized, and is a frequent condition in domestic ruminants (twin-lamb disease or pregnancy paralysis in sheep; ketosis and downer cow syndrome in dairy cattle). • A critical factor in the development of ketosis is insufficiency of glucose for brain metabolism. • Glucose is specifically required as an energy source by some tissues. • For example, the brain and central nervous system require glucose, although ketone bodies can be used to some extent. • The energy requirement of the brain under normal circumstances is met almost entirely from the metabolism of glucose. • The blood-brain barrier limits the penetration of large molecules, such as lipids, into the brain. • As a result, the brain depends on glucose to meet its very high energy needs. • Ketosis in dairy cattle generally occurs in the early stage of lactation in cows in negative energy balance. • Inciting factors include an inadequate post-parturient feed intake, high milk production and mobilization of body lipid to sustain energy needs, especially in cows with high body fat. • There is a lack of carbohydrate precursors such as propionate and amino acids for incorporation of fats (as acetyl CoA) into the citric acid cycle, so ketone bodies are produced at greater rates. • Ketosis is often secondary to other disorders that depress feed intake.

Saturated Fatty Acid

Lauric acid Myristic acid Palmitic acid Stearic acid

Abnormalities of Bone

Leg abnormalities are a problem in poultry, especially in birds kept on wire. • Perosis, or slipped tendon is caused by deficiencies of choline and manganese. Perosis is due to an abnormality of the joint in the long bones of the leg, causing the tendon to slip and pull the leg sideways. • Cage layer fatigue is a type of osteoporosis that involves excessive mobilization of calcium from the leg bones, which causes the birds to have difficulty standing and broken bones. • It is primarily a problem with layers kept in wire cages at high stocking density. • Another leg disorder seen in broilers is tibial dyschondroplasia (TD) in which there is abnormal formation of cartilage in the long bones. • The cartilage forms a thickened layer below the epiphyseal plate. The lesion arises from the failure of growth plate chondrocytes to differentiate. • Dietary electrolyte balance and dietary alterations that affect acid-base or cation- anion balance have a role in TD

Glycemic Index Ratings

Low GI - <55 Medium GI - 56-69 High GI - 70>

Metabolic Syndrome is characterized by, except??? Mark the wrong answer.

Low blood cells count or Hyper-glycaemia?

Which disease combination both are correlated with energy metabolism?

Metabolic Syndrome - Equine Metabolic Syndrome

Use the words below to complete the sentence. Ketosis is a _____________________________. Ketosis develops due the insufficient of __________________________. Ketosis in dairy cattle occurs in the early stage of ___________________________.

Metabolic disease, Glucose, Lactation.

Minerals

Mineral elements are the inorganic components of plant and animal tissues. In animal nutrition, they are classified in two categories: Macro-minerals; Micro-minerals or trace Minerals • Sodium, Potassium and Chlorine are involved as electrolytes in regulating fluid balance between the gut, blood, cells, tissue spaces and body cavities. • Sulfur as such is not a dietary essential, but is a component of many organic constituents of tissue such as the sulfur-containing amino acids, the vitamins biotin and thiamin. • Mucopolysaccharides such chondroitin sulfate, and the metabolically essential coenzyme A (CoA) Other elements regulate enzyme activity, either as integral components of enzymes or as cofactors. As examples: Selenium as an integral component of the enzyme glutathione peroxidase Copper as a cofactor of cytochrome oxidase. There are other minerals like, Vanadium, Silicon, Boron, and Nickel, for which dietary need has been demonstrated only in laboratory animals fed with purified diets.

Vaccines cause autism

NO

Auto-Enzymatic Animals

Non-ruminants

Unsaturated Fatty Acid

Oleic Acid (C18 Monounsaturated) Linoleic Acid (C18 Polyunsaturated) Alpha-Linolenic Acid (C18 Polyunsaturated) Gamma-Linolenic Acid (C18 Polyunsaturated) Ricinoleic Acid (C18 Monounsaturated)

One of the factors that can produce KETOSIS in Allo-enzymatic animals is the low production of ???

Propionate

DDT Damage

Reproductive Failure (in birds - eggshell thinning) Immune system problems Nervous system damage Death

Alloenzymatic Animals

Ruminants

Tall Fescue Grass and Reproduction

Tall fescue grass infected with microscopic fungi called endophytes contains endophyte -produced ergot alkaloids. Pronounced impairment of reproduction occurs in livestock consuming endophyte infected tall fescue • Horses are the only livestock whose reactions to the toxic tall fescue are almost exclusively related to poor reproduction. • Mares on toxic tall fescue pasture may experience prolonged gestation, dystocia, agalactia (lack of lactation), edematous placentas and have large, weak foals with elongated hooves. • Foal survival is very low. Abortion may also occur.

Types of Bones

There are two types of bone: (i) dense cortical bone; (ii) spongy trabecular bone. • Bone consists of an organic matrix that becomes mineralized. • The organic matrix is cartilage, consisting primarily of the protein collagen. • The growth of bone in length occurs at the junction of the epiphysis and diaphysis. • As the cartilage grows, bone mineral is deposited to form bone. • When the cartilage ceases growing and is replaced by mineralized bone, the epiphysis and diaphysis unite and bone growth ceases.

Which one alternative can be a sign of Diabetes in the animal??

Thirst and hunger

Trace Minerals

Trace elements are required in very small amounts. The functions are primary in regulatory roles; Trace-Minerals: under 100mg daily Manganese, Zinc, Iron, Copper, Molybdenum, Selenium, Iodine, Cobalt, Chromium.

The fat soluble vitamins

Vitamin A ( Retinol); Vitamin D (Cholecalciferol); Vitamin E (α-tocopherol); Vitamin K (Phylloquinone). Absorption: first into the lymph, then the blood Transport: may require protein carriers Storage: Stored in the cells associated with fat Excretion: less readily excreted, tend to remain in fat storage sites Toxicity: likely to reach toxic levels when consumed from supplements Requirements: needed in periodic doses (perhaps weeks or months)

The water soluble vitamins

Vitamin C (Ascorbic acid); Vitamin B-Complex : B1 (Thiamin); B2 (Riboflavin); B6 ( Pyridoxine); B12 (Cyanocobalamin); Niacin (Nicotinic acid, B3); Folacin (Folic acid, B9); Biotin (B7); Choline; Pantothenic acid (B5). Absorption: directly into blood Transport: travel freely Storage: circulate freely in water-filled parts of the body Excretion: kidneys detect and remove excess in urine Toxicity: possible to reach toxic levels when consumed from supplements Requirements: needed in frequent doses (perhaps 1-3 days)

Selenium Prevents Peroxidation

Vitamin E and the trace element selenium share the property of preventing peroxidation of unsaturated fatty acids in cell membranes. • Virtually all of the disorders and deficiency signs associated with these two nutrients can be explained by their antioxidant properties (an exception is the role of selenium in the thyroid gland). • Selenium helps protect against auto-oxidation of cell membranes by virtue of being a component of an enzyme, glutathione peroxidase, that reduces (by providing hydrogen) peroxides, thus converting them to innocuous products. • Glutathione peroxidase occurs mainly in the cytosol and reduces peroxides before they can attack cell membranes, whereas vitamin E acts within the membrane itself as a second line of defense. • Selenium also functions as a component of a deiodinase that converts the thyroid hormone thyroxine (T4) into its metabolically active form (triiodothyronine) by the removal of one of the four iodines in thyroxine • The usual form of selenium addition to feeds is a salt, sodium selenite. • It has a high bioavailability. The selenium in plants is largely in the form of seleno-amino acids and has a high bioavailability. • The bioavailability of selenium to ruminants is greater with high concentrate diets than with high roughage diets.

Vitamins

Vitamins are organic compounds other than proteins, carbohydrates and lipids that have specific roles in metabolism, and are required in the diet in very small amounts. Deficiency causes a specific disease, which is cured or prevented only by restoring the vitamin to the diet. In most case, these roles are in regulation of enzyme function. As example: Vitamin K = Impaired blood clotting, due the enzyme role of vitamin K. Vitamin A = Deficiency can result in blindness. The term "Vitamin" was created in 1912 by Polish chemist, Casimir Funk. Vitamins can be classified in two groups: The fat soluble vitamins and the water soluble vitamins

Vitamin E Roles in Reproduction

Was in the past sometimes called the 'fertility vitamin' or 'anti-sterility factor'. - This designation was an accident of history. In the early days of vitamin research, what had been called 'fat- soluble vitamin A' was fractionated into what we now know as vitamin A and vitamin D. Rats fed with these two vitamins along with all other nutrients known at that time did not reproduce normally. Supplementation of the rats with various foods restored fertility. Wheat germ oil was especially effective. • The active component was isolated and named vitamin E. • When the chemical structure was elucidated, it was named 'tocopherol' from the Greek words for childbirth and 'to bear'. • However, despite this early association with reproduction, vitamin E functions primarily as an antioxidant. • Its reproductive effects are actually due to the maintenance of tissue structural integrity by antioxidant activity

Respiratory Quotient (RQ)

the volume of CO2 produced when the respiratory substrate is respired, dividing by volume of oxygen consumed, in a set period of time RQ gives an indication of the respiratory substrate being respired and whether respiration is aerobic or anaerobic

Lipids Structure 2. Lipids that containing Glycerol

• 1. Neutral Lipids: - The major neutral (uncharged) lipids in animal nutrition are the triglycerides, also known as tri-acylglycerols. Triglycerides are the fats and oils. The term triacylglycerol (TAG) is now the preferred term • 2. Phospholipids: - Phospholipids contain one or more phosphate groups. Phospholipids are important constituents of cell membranes and nerve tissue. An example is lecithin. • 3. Waxes: - The surfaces of plants are often covered in a protective layer of wax or cutin. Waxes are lipids with fatty acids esterified to an alcohol other than glycerol. • 4. Sphingolipids - Sphingolipids contain a long-chain alcohol, sphingosine. - Sphingomyelins are phospholipids containing ceramide, the fatty-acid derivative of sphingosine. - Sphingolipids are major constituents of nerve tissue (cerebrosides and gangliosides) and they occur in cell membranes in general. - common mycotoxin in maize, fumonisin, is structurally similar to sphingosine. Fumonisins inhibit sphingosine biosynthesis, causing impaired brain synthesis of sphingolipids.

Lipids Structure 3. Other Lipids

• 1. Steroids: - Are fat-soluble substances that contain the steroid nucleus. - Cholesterol is the best-known steroid, and is the ultimate precursor of many others, including vitamin D, bile acids, sex hormones (testosterone, oestrogen, progesterone), corticosteroid hormones (cortisol, corticosterone, aldosterone), anabolic steroids, etc. • Examples of steroid hormones synthesized from cholesterol. (Cholesterol -> Progesterone -> Testosterone -> Estradiol Progesterone -> Cortisol -> Cortisone Progesterone -> Aldosterone ) • 2. Eicosanoids: - Eicosanoids are compounds derived from 20-carbon and 22-carbon fatty acids, and include prostaglandins, prostacyclins, thromboxanes and leukotrienes. These substances have hormone or hormone-like roles in vasoconstriction and blood

How do specific nutrients affect immunity in dairy cattle?

• A general mechanism by which nutrients support the immune system is via provision of antioxidants. • Immune cells are characterized by high levels of reactive oxygen species (ROS) which are used, in part, to kill ingested pathogens. • In addition to high ROS generation, immune cell membranes are rich in the polyunsaturated fatty acids which are susceptible to ROS-mediated damage. • Nutrients with antioxidant properties (carotenes, vitamin E, vitamin C, zinc and selenium), therefore, support immunity

Environmental Pollutants and Reproduction

• A variety of environmental pollutants have adverse effects on reproduction in wildlife. • They primarily exert their effects through modulating or disrupting the endocrine system. • Many mimic endogenous hormones in chemical structure. • Synthetic (man-made) chemicals that act as hormone mimics include organochlorine pesticides (DDT and its metabolites, endo-sulfan, toxaphene, dieldrin), polychlorinated biphenyls (PCBs), dioxins and a further variety of industrial chemicals. • Many of these endocrine-disrupting chemicals affect estrogen and androgen metabolism. • There is some evidence of declining sperm counts in humans that may be linked to environmental pollutants.

Phyto-estrogens and Reproduction

• An interesting situation is that phyto-estrogens may be involved in the regulation of reproduction of California quail. • Is reported that during dry years, stunted desert plants produced high contents of estrogenic isoflavones that inhibited quail reproduction. • Phyto-estrogens may act as 'anti-estrogens'. • A high blood concentration of Phyto-estrogens may inhibit the release of gonadotropic hormones from the pituitary and may compete with endogenous estrogens for receptor sites in target tissues such as the uterus and cervix. • Also poor reproduction of captive cheetahs in zoological parks in North America may be due in part to the effects of Phyto-estrogens in soybean meal, used in a commercial zoo feline diet. • Because, cats have a low activity of liver enzymes involved in metabolism and excretion of toxins, they may be more sensitive than livestock are to plant estrogens. • Carnivores would be expected, on an evolutionary basis, to have a lower ability to detoxify plant toxins than have herbivores, which have co-evolved with plants heavily defended with toxic chemicals. • Thus, the inclusion of plant products such as soybean meal in diets for carnivores, may have unanticipated detrimental effects.

4- Minerals

• Animals have a well-recognized appetite for salt (sodium chloride). • This salt appetite is often triggered by low contents of sodium relative to potassium in plants, as well as sodium deficiency in forages. • Sodium and potassium are two of the major blood electrolytes. A sodiumto-potassium imbalance may disturb blood electrolyte balance; therefore, the animal is attracted to sources of the deficient mineral. • Diets of herbivores tend to be high in potassium relative to sodium. • Ruminants have a pronounced ability to conserve sodium. • The rumen acts as a sodium storehouse. When sodium-deficient diets are consumed, rumen sodium is drawn upon to counteract blood sodium depletion, and potassium, which is abundant in grass, replaces sodium in saliva. • These mechanisms allow ruminants to adapt to the large sodiumdeficient areas of the world, which include most non-coastal land areas. • Northern ruminants, such as moose, eat large amounts of sodiumcontaining aquatic plants during a 3-month season and draw on the rumen sodium pool during the rest of the year.

8 - Learning and Conditioning

• Animals often exhibit neophobia, a reluctance to accept a new food. • Such a reaction can have practical implications. Where supplemental feeding of livestock is required under drought conditions, grain or pellets may be the least expensive and most convenient sources of emergency feed. • However, sheep that have never eaten these feeds may not recognize them as feed and may starve. • The learning process was accelerated if there were some experienced animals in the flock. • Animals that have learned to eat a novel feed at a young age will readily accept it again even after a several-year lack of exposure to it.

Herbivores

• At the other end of the spectrum, herbivores are animals that normally consume only plant material and have a more complex digestive tract with symbiotic microbial activity that permits the digestion of plant fiber. • Herbivores include the: - ruminants, such as cattle, - non-ruminant herbivores, such as horses and rabbits. • Ruminant animals vary considerably in their feeding strategies. • Ruminants can be classified, (special the wild ruminants) into three groups based on feeding strategy: (i) concentrate selectors; (ii) bulk and roughage eaters; (iii) intermediate feeders

Energy Storage as body fat

• Body fat is stored as TAGs in specialized fat cells (adipocytes). • As with glycogen, body fat is mobilized or deposited in accordance with energy needs of the tissue cells, with these processes controlled by hormones. • Some of these include insulin, epinephrine (adrenalin), norepinephrine (noradrenalin) and adrenocorticotropic hormone (ACTH). • Insulin inhibits the catecholamine-stimulated release of free fatty acids (FFAs) from adipose tissue, and is a major regulator of adipose tissue metabolism. • A body weight regulatory hormone, leptin, stimulates lipolysis and inhibits lipogenesis by influencing the activity of enzymes involved in fatty acid synthesis and degradation. • The main influence of leptin is in regulation of feed intake. TAGs in adipose tissue undergo continual breakdown and deposition, regardless of the need for energy storage or mobilization (the dynamic state of body fat). • For this reason, and the lack of modification of dietary-derived fatty acids, the carcass fat of non-ruminant animals tends to resemble (in fatty acid composition) the dietary fat. • If a pig is fed a diet with mainly saturated fatty acids, its body fat will be saturated; if it is fed unsaturated fatty acids, its body fat will be unsaturated. • In the case of ruminants, the carcass fat tends to be more saturated, regardless of the diet. • Explanations for this include the biohydrogenation of unsaturated fatty acids in the rumen, and the fact that much of the body fat in ruminants is synthesized from absorbed acetate, producing palmitic acid (16:0) and stearic acid (18:0).

Young Horse Bone Disorders

• Bone development disorders are of major concern in young horses. - This concern is particularly true in the thoroughbred racing industry. - Horses with abnormal bone development will not reach their racing potential and are susceptible to injury. • The term developmental orthopedic diseases (DOD) is used to describe a complex of bone disorders, including osteochondrosis (OCD), physitis, contracted tendons, cervical vertebral malformation (wobbler syndrome) and similar abnormalities. - OCD is a disease of the growth cartilage at articular or epiphyseal growth regions. It may occur at the growth plate (physis) or in developing the articular cartilage of joints.

Bones

• Bones serve as the structural components of the skeletal system and are also storehouses of minerals, especially calcium and phosphorus, which can be mobilized as needed. • Bone is in a continuous state of formation and mobilization - it is in a dynamic state, also known as remodeling.

Brown Adipose tissue

• Brown adipose tissue (brown fat) is a special type of body fat especially important in newborn animals and animals that hibernate. • Brown fat is characterized by a well-developed blood supply, an abundance of mitochondria and respiratory chain enzymes, and a low activity of ATP synthase. • It is brown in colour because of the large numbers of mitochondria

Carnivores

• Carnivores, such as cats, are adapted to a meat-based diet and require a high quality, highly digestible source of nutrients. • Carnivores (mammalian, avian, reptilian) have simple digestive tracts with little microbial activity. • They may require certain nutrients, such as preformed vitamin A, some fatty acids and taurine, that in the wild can be obtained only from consumption of meat.

Carotenoids and Antioxidants

• Carotenoids are an abundant group of plant pigments; over 600 individual carotenoids are known. • They contain a long chain of conjugated double bonds, and most (e.g. beta-carotene) but not all (e.g. lycopene) have a beta-ionone ring (which is necessary for vitamin A activity). • The chain of conjugated double bonds has antioxidant activity. • In plants, carotenoids are found in the chloroplasts and function in photosynthesis. • Carotenoids are part of skin and feather pigments. They contribute to the antioxidant defenses of animals.

Carotenoids

• Carotenoids are plant pigments and antioxidants that include ß-carotene, lutein, canthaxanthin, lycopene and astaxanthin. • Carotenoids (i.e.ß-carotene) have traditionally been viewed as a source of vitamin A via the cleavage of ß-carotene precursor into active forms of vitamin A. However, carotenoids have immuno- stimulatory properties independent of their roles as precursors of vitamin A.

Chromium Importance

• Chromium is known to enhance the action of insulin , a hormone critical to the metabolism and storage of carbohydrate, fat, and protein in the body

9 - Metabolic body size

• Common experience indicates that the feed intake of animals does not vary directly with body size. • The smallest mammal, the shrew, weighs approximately 1-6 g and eats its body weight in food daily. • It has an intense rate of metabolism and eats voraciously just to keep alive. A shrew can die of starvation after as little as 3 h without food. • It is evident that the larger an animal is, the less feed it consumes per unit of body weight. • Obviously, an elephant does not consume its body weight in feed each day.

Diabetes

• Diabetes mellitus (diabetes from Greek referring to excessive urination; mellitus from Greek referring to sugar in urine) is a metabolic disorder characterized by elevated concentrations of blood glucose (hyperglycaemia). • There are four major categories of diabetes: - (i) Type 1 (ii) Type 2 (iii) gestational (iv) secondary The major ones, Type 1 and Type 2, will be the ones discussed here. Type 2 is the most common form; 90-95% of the diabetics in the USA have this type.

3- Protein and Amino acid Concentration

• Dietary energy density has a much greater impact on voluntary feed intake than does dietary protein status. • Nevertheless, protein intake in growing animals is subject to some regulation. The growing pig, for example, has the ability to preferentially select diets adequate in essential amino acids over amino-acid-deficient diets. • Baby pigs are able to discriminate among diets varying in methionine content, and prefer a diet balanced for methionine over a methioninedeficient diet. Plasma concentrations of certain amino acids (e.g. lysine and tryptophan) provide signals for release of neurotransmitters, such as serotonin in the brain, that play a role in feed-intake regulation.

Omega-3 and 6 fatty acids

• Dietary fatty acids can affect immunity through the production of the cytokines. • A mechanism by which fatty acids affect immunity is through production of eicosanoids (e.g. prostaglandins) and leukotrienes.

Nutrition and Reproduction in Livestock

• Energy intake of beef cows is a major determinant of reproductive efficiency. • It is of particular concern in relation to estrous cycles and initiation of pregnancy. • After calving, beef cows should be rebred within 60-90 days to maintain a once-per-year calving interval. • This postpartum period is one of high energy requirements to support lactation. • If a cow is not able to consume sufficient feed to maintain a positive energy balance, initiation of estrous cycling may not occur, resulting in a prolonged calving interval. • Grazing cattle may not be able to consume a sufficient amount of forage to maintain a positive energy balance and may have a prolonged postpartum anoestrus period. • Cows with high milk production are particularly susceptible. • Feeding fat to dairy cows results in improved reproductive performance. • One mode of action is simply the provision of extra energy to prevent negative energy balance. • There is a specific advantageous effect of polyunsaturated fatty acids on dairy cow reproduction, causing changes in plasma estradiol, progesterone and prostaglandins, with stimulation of ovarian follicular growth.

Energy Storage

• Energy is stored mainly as triacylglycerol (TAG, in adipose tissue) or carbohydrate (glycogen). • More energy is stored in a given weight of tissue as TAG than as carbohydrate. • TAGs are energy-rich (9 kcal/g) as compared to carbohydrate (4 kcal/g), so per unit of body weight, more energy can be stored as TAG. • Saturated fatty acids yield more energy than unsaturated fatty acids, because they contain more hydrogen (ATP is formed when hydrogen-containing cofactors, e.g. FADH2 , NADH, NADPH, are oxidized in the respiratory chain)

Equine Metabolic Syndrome

• Equine metabolic syndrome is a disorder in horses with similarities to human metabolic syndrome. • Affected horses are obese, have insulin resistance and chronic laminitis, in the absence of usual inciting factors for laminitis. • Affected horses are often grossly obese, with excessive accumulation of adipose tissue in the crest of the neck, over the rump and around the tail head. • Treatment involves strict limitation of soluble carbohydrates in the diet. • Grain feeding and pasture should be avoided, with the diet based on good quality grass hay (1-1.5% of body weight/day). • The causes of laminitis in horses with equine metabolic syndrome are not well defined. Increased cortisol secretion caused by disturbances in fat metabolism may play a role in the predisposition to laminitis.

Estimation of Feed Energy

• Feed energy is actually measured as calories, by bomb calorimetry, and then converted to joules by a conversion factor (below). Appropriate definitions and conversions are as follows: • 1 calorie (small calorie) = the amount of heat required to raise the temperature of 1 g of water by 1°C degree centigrade, measured from 14.5 to 15.5°C; • 1 kilocalorie (kcal) = 1000 calories = 1 Calorie (large calorie);1 • 1 megacalorie (Mcal) = 1000 kilocalories; • 1 calorie = 4.184 joules (J);

Feeding Behavior

• Feeding behavior and digestive tract physiology in animals are closely interrelated. • The feeds normally consumed by animals are those they are capable of digesting. • There are three major types of animal feeding behavior: • (i) carnivorous; • (ii) omnivorous; • (iii) herbivorous.

Foods on the Glycemic Index

• Foods with: • High glycaemic index (70-99) include corn flakes, baked potato, croissant, candy; • Medium glycaemic index (56-69) foods include whole wheat products including bread, rice, sweet potato and table sugar; • Low glycaemic index foods include most fruit and vegetables, pasta, legumes/pulses (e.g. beans and peas) and low carbohydrate foods (meat, fish, eggs, oils).

Glucose Tolerance

• Glucose tolerance is the ability of the body to regulate blood glucose after the administration of a test dose of glucose. • Glucose tolerance is impaired in both Type 1 and Type 2 diabetes. • In a normal glucose tolerance test, blood glucose returns to normal rapidly in a normal subject. • In an individual with impaired glucose tolerance, the blood glucose rises to a high peak and returns to normal more slowly, because of impaired glucose uptake by the body tissues. • In Type 1 diabetes, this is due to lack of insulin, while in Type 2 it is caused by insulin resistance. Oral Glucose Tolerance Test (OGTT)

Storage of Glycogen

• Glycogen is the major storage carbohydrate in animals. • It is sometimes called animal starch, and like plant starch, it is a branched polymer of a-D- glucose. • Glycogen is stored in the liver and muscle tissue. • The main function of liver glycogen is to provide glucose to maintain the blood glucose concentration (glucose homeostasis), to provide a constant supply of glucose for extrahepatic cellular metabolism. • Muscle glycogen is a readily available source of fuel for muscle contraction. • Glycogenolysis is the process of glycogen breakdown. • In liver, this process yields glucose, while in muscle the major end product is lactic acid.

Gossypol and Reproduction

• Gossypol is a toxin found in cottonseed and cottonseed meal. • Gossypol has some interesting effects on reproduction. - Much of the interest stems from observations on humans in China and the possible development of a male birth control pill. A Chinese scientist reported that in a 10-year period, not a single child had been born in Wang village in Jiangsu. It was discovered that a crude, homemade cottonseed oil preparation had been used for cooking in this village. Women lacked menstrual cycles and men were sterile. Subsequent investigation linked these conditions to the consumption of gossypol. • Gossypol causes males to be infertile because of non-motile sperm and depressed sperm counts. • Specific lesions occur in the spermatozoa and in the germinal epithelium. • In females, gossypol disrupts estrous cycles, pregnancy and early embryo development, particularly in non-ruminants. • The ruminant female is somewhat insensitive to the antifertility effects of gossypol.

Hibernation

• Hibernation is a state of hypometabolism entered into by some animals as a response to anticipated nutritional stress. • While generally viewed, as a means of avoiding winter-feed scarcity and cold, hibernation is employed also by some animals (e.g. California ground squirrel) to avoid hot summer months when grass seeds are unavailable (also called aestivation) • Aestivation in hot, dry conditions is common among reptiles. • Hibernation is characterized by an extreme drop in body temperature (to as low as -2.9°C) and metabolic rate can be as low as 1% of normal. • This state is known as torpor. • A typical hibernation season is characterized by several bouts of torpor, interrupted by short periods of intense metabolic activity. • For reasons as yet unknown, they expend significant amounts of energy to periodically rewarm back to normal body temperature for less than a day before recooling. • Hibernators are of two types: • (i) fat storing; • (ii) food storing. • Fat-storing hibernators do not consume food during the hibernation season and instead rely on metabolism of stored fat (white adipose tissue; WAT). • Fat-storing hibernators, such as ground squirrels and marmots, can virtually double their body weight prior to hibernation, with 60-80% of the weight as WAT. • Adipose tissue is the most efficient form of fuel storage, because body fat is energy dense, and non-hydrated. Body protein is also catabolized for energy during hibernation. • Hibernating bears utilize protein for energy, and recycle urea back into amino acids, by ammonia fixation. • Food-storing hibernators (e.g. chipmunks) store caches of food, which they ingest during their periodic arousals.

Ancestral Human diet, Paleolithic Nutrition (the Caveman diet)

• Human nutritional requirements reflect our evolutionary history extending millions of years into the past . • Genetically, today's humans are basically the same biological organisms as our ancestors when they took up agriculture a scant 3000-10,000 years ago. Thus our ancestral dietary pattern has continuing relevance to the nutritional needs of contemporary humans • Small populations of hunter-gatherers still exist. These populations have a low dietary intake of fats rich in saturated fatty acids, because of the leanness of wild game. • However, their cholesterol intake was high, about 480mg/day. Despite this, they maintain very low serum cholesterol concentrations (about 1,250 mg/L). • Their high ratio of polyunsaturated to saturated (P:S) intakes (1.4 for hunter-gatherers, 0.4 for contemporary Americans), low saturated fatty acid intake and low total fat intake apparently balance the high cholesterol intake. • Ancestral human diets contained much more protein and fiber than do contemporary diets. • Thus meat consumption is consistent with good health, which, based on archaeological evidence, hunter-gatherers apparently enjoyed. • However, the fatty acid composition of contemporary intensively fattened meat animals deviates markedly, in an undesirable manner, from the lipid content and fatty acid composition of wild game animals. • In a review of palaeolithic nutrition (the caveman diet) point out that, while early humans consumed a diet high in meat, the actual nutrients consumed may have been quite different from those in today's Western-type diet. • The importance of meat in the caveman diet is revealed by the abundance of animal bones and hunting tools in archaeological sites, and the absence of much evidence of plant foods and tools • While the human genetic profile has not changed much in the past 40,000 years, our current Western diet has changed markedly over this time, with an increase in total fat, saturated fatty acids, trans-fatty acids and ω-6 essential fatty acids, but a decrease in ω-3 fatty acids. • The ratio of ω-6 to ω-3, and fatty acids is 10-20:1 today, whereas in preagricultural times it was about 1:1. This change arose because of our use of vegetable oils (mainly ω-6) and grain-fed meat animals, with carcass fat high in saturated and ω-6 fatty acids. • The major dietary energy sources for modern humans are the cereal grains (cereal grains are the edible seeds of grasses). • Three cereal grains, wheat, maize (corn) and rice, make up over 75% of world grain production, providing over half of the food energy consumed by humans. • When cereal grains replaced the animal-based diets of hunter-gatherers, there were characteristic negative effects such as a reduction in stature, increased infant mortality, reduced lifespan, increase in infectious diseases, increase in iron deficiency anemia, increased osteomalacia, and increased dental caries and enamel defects.

Hypocalcaemia and parathyroid hormone (PTH)

• Hypocalcaemia is common in dairy cattle; it is referred to as milk fever or parturient paresis. • It occurs most frequently soon after lactation begins, because of a hormonal insufficiency, coupled with a high calcium demand for lactation. • Normally, bone mineral is mobilized to meet the high calcium requirement of lactation. • Mobilization of bone mineral is stimulated by various hormones, especially parathyroid hormone (PTH). • It is often considered desirable to 'prime' dry cows on a low calcium diet to stimulate endocrine activity so that when lactation begins a high rate of mobilization of bone calcium can occur as a result of increased PTH secretion. • The bone mineral is replenished during the dry (non-lactating) period.

2- Dietary Energy Level

• If feeds are sufficiently palatable to be readily consumed, the main dietary factor that controls voluntary feed intake is dietary energy concentration. • A long-standing order in animal nutrition is that animals eat to satisfy their energy requirements. • The amount of feed consumed is regulated so as to provide a constant intake of digestible energy. • If a low energy diet is used, feed intake is high, whereas with a high energy diet, feed intake is reduced. • The energy intake is about the same in each case, the lower limit of this relationship is when gut capacity is reached and the animal cannot consume enough feed to meet its energy requirements; thus its performance is reduced.

Novel Nutritional Strategies to Augment Immunity

• In addition to providing adequate amounts of all essential vitamins and minerals, other opportunities may exist for augmentation of immune function. • Provision of microbiological fractions (cell wall fractions) and probiotics (live microorganisms) in the diet have potential to support the immune system. • Although it is not fully clear how this form of nutritional supplementation benefits the immune system, it is possible it includes Toll-like receptor signaling in the gastrointestinal tract

Osteomalacia

• In adults, bone demineralization occurs with a deficiency of calcium, phosphorus and/or vitamin D. This condition is known as osteomalacia (adult rickets).

Fat and Fatty Acid Metabolism

• In general, because lipids are insoluble in water, they are transported in blood in association with serum proteins, forming lipoproteins. • The main lipoproteins (as determined by centrifugation) are: - chylomicrons; - very low density lipoprotein (VLDL); - low density lipoprotein (LDL); and - high density lipoprotein (HDL). • Liver: • The liver has a central role in lipid transport and metabolism, with the following major functions: - It facilitates the digestion and absorption of lipids by secretion of bile. - It synthesizes and oxidizes fatty acids. - It converts fatty acids to ketone bodies. - It is involved in the synthesis and catabolism of lipoproteins.

Rickets

• In growing animals, the primary sign of deficiency of calcium, phosphorus and/or vitamin D, is rickets. • Rickets is characterized by spongy, poorly mineralized bones, leading to lameness, fractures, misshapen bones and death.

Type 2 Diabetes

• In humans, Type 2 diabetes occurs most frequently in middle-aged and older adults. • Most people with this condition have normal or above normal concentrations of blood insulin. • Type 2 diabetes is caused by insulin resistance, which means that the body's cells cannot respond to insulin. • Insulin functions in the transfer of glucose across cell membranes. • Insulin binds to insulin receptors on the surface of tissue cell membranes, allowing glucose to enter the cells. • Insulin resistance occurs when the cell receptors do not recognize or bind insulin. • With insulin resistance, glucose uptake is impaired and hyper-glycaemia results. • Chronic hyper-glycaemia damages blood vessels and nerves, sometimes leading to blindness and limb amputation. • Some Type 2 patients respond to exogenous insulin, although insulin resistance does not imply a lack of the hormone. • In these patients, a chronic over stimulation of the pancreas to produce more insulin in response to hyper-glycaemia may eventually cause the pancreatic (beta-cells to 'wear out'). • Besides its role in diabetes, insulin resistance is also a major factor in the development of metabolic syndrome, in both humans and equines.

Serum Calcium

• In most species, calcium absorption is regulated by need, via the 1,25-OHD3 (vitamin D) pathway, ultimately controlled by the serum calcium concentration. • Serum calcium is homeostatically regulated by the actions of PTH (in response to hypocalcemia) and calcitonin (in response to hypercalcemia). • Calcitonin is produced in the thyroid gland. • Excess dietary calcium is not absorbed in most species and is excreted in the feces. • Urinary excretion is not a major pathway of calcium loss in most species.

Non-Ruminant Nutrition and Immunology

• In non-ruminants: affect one or more indexes of immunity • essential amino acids, • linoleic acid, • vitamin A, • folic acid, • vitamin B6 , • vitamin B12, • vitamin C, • vitamin E, • zinc, • copper, • Iron, • selenium. • Also, potential roles of magnesium in support of the immune system. Vitamin E and zinc have received the most attention as immuno-stimulatory nutrients.

5 - Forage Composition

• In ruminants, forage quality and composition influence feed intake. • A major factor regulating forage intake is the neutral detergent fiber (NDF) and its digestibility. • The NDF seems to be the major component limiting rumen fill. In the rumen, only when the NDF is digested is its effect on rumen fill eliminated ,confirmed this relationship with cattle; the intake of forage is regulated by the intake of indigestible NDF. • The water-holding capacity of feedstuffs may affect feed intake. Feeds with high water-holding capacity include wheat bran, beet pulp, and grains (e.g. wheat.

Caloric Restriction and Longevity

• In the 1930s, McCay et al. (1935) at Cornell University reported that growing rats fed a severely restricted allotment of food, sufficient to cause growth to cease, had elongated lifespans. • When they were older than the normal lifespan of rats, they were still capable of growing and nearly reaching normal body size. This study was the first major research which demonstrated that caloric restriction retards ageing and extends median and maximal lifespan. • Since this work, similar findings have been reported for a variety of species including rats, mice, fish, flies, worms and yeast. • A 25% diet restriction of dogs resulted in increased lifespan in a two-decade study (Lawler et al., 2008). • Large animals tend to live longer than small animals, a relationship which correlates with metabolic rate. • The naked (African) mole rat has an extraordinarily long maximum lifespan exceeding 28 years. Mole rats in captivity live over nine times as long as similar sized mice. They show no decline in fertility even into the third decade of life, and have never been observed to develop neoplasms. • Compared to other animals of similar size, such as sheep and pigs, humans also have an extremely long lifespan.

Vitamin A

• In the feed is more common as pigments (Carotenoids) provitamin A; • Storage most in the liver • Horses, Cattle, and Chickens can absorb more carotenoids than swine, sheep and rats; • Cats can not convert carotenoids in Vitamin A. • Functions: - Vision - Gene transcription, - Immune function, - Embryonic development and reproduction, - Bone metabolism, - Haematopoiesis, - Skin and cellular health, - Teeth, - Mucous Membrane.

Calcium importance and functions

• It is the main element in bone tissue, that include 99% of the corporal calcium, and around 75% of all phosphorus in the body (Bones and teeth). • Adult cow has: 6 kg of calcium, and 2.8 kg of phosphorus in the body, the correlation of Ca:P is 2:1. • In the milk that correlation is 1:1 (can cause deficiency of P) • In the sheep, that correlation Ca:P is 3:1 Calcium Functions: - Formation of bone matrix - Essential factor in the coagulation of the blood - Participation in the muscle contraction process - Act as adjuvant in the process of neural signaling transmission - Enzyme regulation (calmodulin, muscle contraction) - Act as a second message to some hormones

Lipids Structure

• Lipids are defined as those constituents of plants and animals tissue that are soluble in organic solvents like diethyl ether. • The lipids content of feeds is usually referred to as the ether extract (EE). Dietary lipids of importance in animal nutrition are mainly fat and oils, which are energy-rich compared with carbohydrates, having about 225% the energy content to carbohydrates on an equal weight basis. They also function as components of cell membranes and as the 'insulation' of nerves. The lipid component of animal products (body fat, cholesterol) is important in human nutrition, and is implicated in various human health pathologies

Lipid Digestion - Auto-Enzymatic Animals

• Lipids are hydrophobic, meaning that they are not soluble in water. • Therefore, a fundamental aspect of lipid digestion is to 'dissolve' fat in water, that is, in the aqueous medium of the digestive tract. • This is accomplished by emulsification, or the dispersal of lipid in water in the form of very small droplets • Bile contains bile salts, lecithin, and substances derived from cholesterol so it acts as an emulsifier. • It attracts and holds on to fat while it is simultaneously attracted to and held on to by water. • Emulsification increases the surface area of lipids over a thousandfold, making them more accessible to the digestive enzymes. • Once the stomach contents have been emulsified, fat-breaking enzymes work on the triacylglycerols and diglycerides to sever fatty acids from their glycerol foundations. • As pancreatic lipase enters the small intestine, it breaks down the fats into free fatty acids and monoglycerides. • Bile salts envelop the fatty acids and monoglycerides to form micelles. • Micelles have a fatty acid core with a watersoluble exterior. • This allows efficient transportation to the intestinal microvillus.

10 - Other factors

• Many other factors, often in combination with some of the items mentioned before, may influence feed intake. • Smell is very important. Sometimes animals will reject a diet or a forage without even tasting it, suggesting that olfactory cues are involved. • Grazing animals will not graze in the immediate area of manure droppings, but the grass around the dung is cut and taken. • Fatigue can limit feed intake. Ruminants consuming coarse forages may become fatigued in seeking, ingesting, chewing and ruminating feed. • Rumination time is directly related to plant cell wall content. Sheep and cattle have a maximum rumination time of approximately 10h/day and cannot be forced to ruminate beyond this limit. • Illness (sickness behaviour) that involves activation of the immune system results in loss of appetite. This is a consequence of the metabolic actions of various cytokines, such as interleukins and tumour necrosis factor.

Metabolic Syndrome

• Metabolic syndrome has been proposed as a disorder in humans characterized by: - impaired insulin sensitivity, - hyper-glycaemia, - elevated blood triacylglycerol (TAG), - abdominal obesity and hypertension. Insulin resistance refers to the lack of effect of insulin in stimulating glucose uptake by tissue cells, resulting in hyper-insulinaemia and hyperglycaemia. Similarly, normal effects of insulin on lipid metabolism are reduced, causing elevated blood TAG and lower HDL cholesterol concentrations. • Metabolic syndrome increases risk of Type 2 diabetes and cardiovascular disease. • Dietary factors may influence hyper-insulinaemia. • For example, chili peppers (Capsicum annum) decrease postprandial (after eating) blood insulin concentrations, which may have a favorable effect on lowering insulin, obesity and cardiovascular disease. • A number of other herbs can have similar effects.

Mycotoxins

• Mycotoxins play a role in other leg disorders of poultry. • A frequent cause of rickets in young poultry is calcium deficiency induced by aflatoxins. - Aflatoxins cause liver damage and reduced bile secretion. - Bile is necessary for the absorption of fat-soluble vitamins such as vitamin D. - Aflatoxin reduces vitamin D absorption and the liver damage impairs formation of 1-25-OHD3 in the liver. - Another mycotoxin, fusaro-chromanone, has been implicated as a causative agent of TD in broilers.

Copper

• Natural copper deficiency increases susceptibility of ruminant animals to disease. • Several studies have investigated effects of copper on immunity in ruminant animals. • It should not be surprising that copper supports immunity as it is associated with many proteins

Nutrition and Immunology

• Nutrition has an impact on every physiological process in the body. • Hence, it should not be surprising that nutrition also has important implications on immunity and incidence of disease. • While scientists have known for many years that nutrition influences immunity, only in recent years have specific mechanisms by which nutrients affect immunity become apparent.

Nutrition and Reproduction

• Nutrition plays important roles in reproductive success. • Growth of the fetus and placental tissues have a high priority for nutrients, especially those relating to energy and protein requirements. • The ultimate role of all organisms is the successful completion of reproduction.

Omnivores

• Omnivores are animals that are less fastidious in their feeding behavior and consume a wide variety of animal and plant foods. Pigs, poultry and humans are good examples.

Measurement of Energy Metabolism

• On a practical basis, energy metabolism of animals is assessed by measuring some general aspect of metabolism. • For example, in the utilization of carbohydrates, lipids and amino acids as energy sources, oxygen is consumed and carbon dioxide, water and heat are end products. • All of these (except water) can be measured in animals confined in special chambers called respirometers. • The ratio of these gases (moles carbon dioxide produced/moles oxygen consumed), the respiratory quotient (RQ), gives an indication of the nature of the metabolic fuel being used. • During metabolism of carbohydrate the RQ is 1.0. • Fatty acid metabolism is associated with an RQ of 0.7. • The RQ for protein is between 0.7 and 1.0. • Heat production can also be measured, and used as an indicator of metabolic rate.

Energy Metabolism and Reproduction

• On an evolutionary basis, animals developed physiological mechanisms which inform them metabolically as to whether undertaking reproduction at a particular time is wise. • For example, it would not be an evolutionarily sound strategy for wild ungulates in northern regions, to give birth in midwinter. • A developing dry season, would result in reduced feed availability, and thus reduced availability of energy-providing nutrients. • Reduced energy intake could provide a cue to alter hormonal status to inhibit reproduction. • In general, low energy intakes and poor body condition will tend to impair reproduction. • Nutrients that are involved in energy metabolism, such as enzyme cofactors, will if deficient impair reproduction. • For example, phosphorus has a role in phosphorylation of sugars in carbohydrate metabolism. • Dietary phosphorus deficiency thus provides a cue that energy metabolism is impaired. • Phosphorus deficiency of livestock is relatively common in various parts of the world where soil contents of the mineral are low.

Vitamin E as an Antioxidant

• Only metabolic function of vitamin E is as a cellular antioxidant, responsible for stabilizing cell membranes. • All symptoms of vitamin E deficiency are in fact manifestations of peroxidation of cell membranes. • Vitamin E associates with lipid micelles in the intestine, and is absorbed coincidently with fat absorption. • It is transported in the blood in association with lipoproteins and within cells is associated with tocopherol-binding proteins.

1- Palatability and Feed Preference

• Palatability is a determinant of feed intake. • Palatability is the summation of the taste, olfactory and textural characteristics of a feedstuff that determine its degree of acceptance. • Taste is a major component of the palatability complex. • The major taste responses are sweet, salty, bitter and acid. • A fifth taste sensation has been recognized, called umami (Japanese meaning savory deliciousness). The umami taste is considered to represent the taste for dietary protein • Virtually all animals except strict carnivores show a preference for the sweet taste (sweet tooth). The sweet taste is recognized by a taste bud receptor composed of the products of two genes. • In the domestic cat and others such as the tiger and cheetah, one of the genes is not functional and is not expressed . • Most animals also show a pronounced appetite for salt. This is particularly true of herbivores. • The attraction for sweet taste (sugars) and fat is of obvious evolutionary benefit, attracting animals to feeds that are rich in energy. While a 'sweet tooth' was of obvious benefit to pre-modern humans, it has become a liability today. • Other palatability factors for various species include size, shape, smell, color and movement.

Fatty Acid Metabolism

• Pathways of fatty acid metabolism involve fatty acid biosynthesis, oxidation, and metabolism of essential fatty acids. • These processes, especially fatty acid biosynthesis and degradation, are intertwined with pathways of carbohydrate metabolism because of the central roles of acetyl CoA in both fat and carbohydrate metabolism. • Fatty acid oxidation • Fatty acids are oxidized in the mitochondria by being converted to acetyl CoA, which is then catabolized in the citric acid (or TCA) cycle reactions. Fatty acids react with coenzyme A (CoA) intracellularly to produce activated fatty acids (acyl CoA). This step requires ATP. • The activated fatty acids are transported across the mitochondrial membrane in association with carnitine. • Fatty acid synthesis • Fatty acid synthesis, like (b-oxidation, involves metabolism of two carbons at a time, in the form of acetyl CoA. • However, fatty acid synthesis is not simply the reversal of B-oxidation, but involves different enzymes located at a different intracellular site. • This separation allows each process to be individually regulated and integrated according to metabolic needs. B-Oxidation occurs in the mitochondria, whereas fatty acid biosynthesis occurs in the cytosol.

Peroxidation

• Peroxidation (auto-oxidation) of lipids exposed to oxygen is an important factor in the deterioration (rancidity) of fat-containing feeds and also for damage to tissues in vivo, where it may be important as a cause of cancer, inflammatory diseases, atherosclerosis and ageing. • The deleterious effects of lipid peroxidation are caused by free radicals produced during peroxide formation from polyunsaturated fatty acids. • A chain reaction occurs, in which the peroxidation processes generate free radicals which initiate further peroxidation. • Other sources of free radicals and lipid oxidants (reactive oxygen species; ROS) are the superoxide free radical anion and hydrogen peroxide. • The superoxide ion is a by-product of normal metabolism. Free radicals have an unpaired electron and are very electrophilic (i.e. they react to gain another electron). • Superoxide is detoxified by the enzyme superoxide dismutase, producing hydrogen peroxide. • Hydrogen peroxide is also a potent oxidant, and is detoxified by the reaction with reduced glutathione (GSH) catalysed by glutathione peroxidase and with catalase • Lipid peroxidation is prevented by antioxidants. • A number of antioxidants are used as preservatives to prevent auto-oxidation of lipids in foods and feeds. • These include butylated hyroxyanisole (BHA), butylated hydroxytoluene (BHT) and ethoxyquin. • Naturally occurring antioxidants include vitamin E and vitamin C. • Selenium has antioxidant activity by way of its role in glutathione peroxidase. • Polyphenols from plant sources also have antioxidant activity. • The phenolic group(s) of antioxidants is the active site; most antioxidants are phenolics, including vitamin E. • Antioxidants either reduce the rate of initiation or interfere with chain propagation. • Those that reduce initiation include catalase and other peroxidases that react with hydroperoxides, and chelators of metal ions (e.g. ethylenediaminetetraacetic acid, EDTA). • Principal chain-breaking antioxidants include superoxide dismutase, which traps superoxide free radicals, and vitamin E, which traps peroxide free • The tocopheroxyl free radical product is reduced back to tocopherol by ascorbic acid (vitamin C). • The ascorbate free radical is converted to ascorbate and dehydroascorbate, which are not free radicals. • Unsaturated fatty acids are susceptible to peroxidation, because they have double bonds which react with oxygen. • The more double bonds (i.e. the more unsaturated), the greater the susceptibility to auto-oxidation.

Ratites

• Ratites (ostriches, emu and other large flightless birds) are susceptible to leg weakness problems. • When fed high energy diets, young ratites may have excessive weight gain that causes great stress on the legs, which may become bowed or misshapen. Therefore, young ratites should be raised on pasture if possible, with limited exposure to concentrate feeds.

Importance and function of minerals

• Represents 2 to 5% of the weight of the animal tissues • Acts as co-factors of enzymatic activity • Activate some hormones • Correlated with osmotic equilibrium • Correlated with the acid basic balance

Chromium

• Several studies have indicated that supplementation of chromium to dairy cattle, in a biologically available form (e.g. chromium-amino acid complex or chromium-yeast), benefits immunity. - Help the increased blastogenesis in lymphocytes recovered from sick calves. - Chromium increased development of titre to ovalbumin immunization and was reported increased titre in chromium-supplemented cows following immunization with infectious bovine rhinotracheitis virus (IBRV) antigen (but not parainfluenza virus Type 3).

Zinc

• Specific roles that zinc plays in support of immunity are plentiful, well established and too numerous to reports. • However, it should not be surprising that zinc plays an essential role as an 'immunonutrient' as it is associated with over 300 proteins . • Clearly, a zinc deficiency has opportunity to impact a large number of cellular events which might compromise immunity .

Synthetic Antioxidants (Preservatives)

• Synthetic antioxidants include: - Ethoxyquin (Santoquin®), - BHT; - BHA. • They are phenolic compounds, and are very effective at preventing oxidation (rancidity) of stored feeds and are commonly used for this purpose. (Ethoxyquin is not actually a phenolic).

Sucrose, Fructose and Metabolic Syndrome

• Table sugar (sucrose) is widely added to processed foods. • The availability of abundant amounts of sucrose is a recent development. • Before the discovery of the Americas and the development of largescale sugarcane production, most humans consumed virtually no sugar, and very small amounts of honey. • Beginning in the 1970s, high fructose corn syrup (HFCS) has become an extensively used sweetener. • Beginning in the 1970s, high fructose corn syrup (HFCS) has become an extensively used sweetener. • The rapid increase in sucrose and HFCS consumption by humans has been paralleled by a rapid increase in 'diseases of Western civilization' such as: - diabetes, - coronary heart disease, - obesity, - hypertension, - kidney disease - metabolic syndrome, Suggesting a possible relationship between sugar consumption and these diseases.

6 - Environmental temperature

• The environmental temperature has an important influence on feed intake. • The metabolic rate of an animal is at a minimum in the comfort zone, also known as the zone of thermoneutrality. • As environmental temperatures decrease below the comfort zone, an increase in metabolic rate is necessary to maintain body temperature. • Thus feed intake increases as environmental temperature decreases. • It is difficult to quantify these relationships (e.g. to indicate that with a 10°C decrease in environmental temperature the feed intake will increase by a certain percentage) because of the involvement of other factors, such as humidity and wind velocity • Hormonal changes influence winter feed intake. • During a period of exposure to cold, the comfort zone is lowered by alterations in the output of such hormones as thyroxine. • The winter hair coat also provides insulation to reduce energy requirements. • Wild ungulates, such as deer, accumulate large amounts of body fat in the summer and have a very low feed intake in the winter, surviving on body-fat stores. • Domestic ruminants appear to have vestiges of this photoperiod-controlled feed intake pattern.

General Concepts of Immunology

• The immune system can be generally separated into three broad components: • (i) natural immunity; • (ii) innate immunity; • (iii) acquired immunity. - All of these must be fully developed and functioning properly to provide adequate immunological protection. - Natural and innate immunity are typically grouped together under the category of innate immunity.

Innate Immunity

• The innate immune system is an evolutionarily ancient mechanism to fight disease and represents the antigen-non-specific defense mechanisms of the immune system that is elicited immediately or within several hours (0-4 h) after exposure to an antigen. • It consists of several anatomic, physiologic and cellular components. • Anatomic aspects include the epithelial barriers to infection provided by the skin, lung, mammary and gastrointestinal tract. • Secretion of hydrochloric acid and digestive enzymes by the gastrointestinal tract also aids in preventing entry of pathogens into the body. • Complement is also considered a component of innate immunity. • But, in addition to these, animals possess a cellular component of innate immunity. • The cellular component consists of phagocytic cells (e.g. neutrophils and macrophages) that are activated at sites of infection and then attack and kill pathogens before pathogens have the opportunity to proliferate and cause a significant infection. • Innate immunity is a non-selective immune system. • It does not modify itself depending upon the type of pathogen challenge. • Instead, it prevents infection by targeting general properties of pathogens. For example, few pathogens can withstand the low pH of the stomach (abomasum) and most should be digested by the digestive enzymes of the gastrointestinal tract. In fact, the majority of organisms encountered by an animal on a daily basis do not cause disease under normal circumstances as they are readily detected and eliminated by the innate immune system.

Immune system and vitamin D

• The most recent essential nutrient with reported benefit to the immune system is vitamin D. • Was reported a link between receptors and vitamin D-mediated innate immunity and suggested that differences in ability of human populations to produce vitamin D may contribute to susceptibility to microbial infection.

Lipid Digestion - Alloenzymatic Animals

• The natural diets of ruminants tend to have a low concentration of lipids. • Leaf lipids are mainly galactolipids and phospholipids, and miscellaneous substances such as waxes, plant pigments (chlorophyll, carotenoids) and essential oils. • Seed lipids are primarily triglycerides (TAGs); therefore, modern feedlot and dairy diets based on grains have a preponderance of dietary lipid as TAGs. • Rumen microbes utilize lipids inefficiently. • In non-ruminants, fats are emulsified by bile before digestion in the small intestine. • In the rumen, there is a lack of emulsifying agent, pancreatic lipase, in the rumen, so high (above 5%) amounts of dietary fat can cause reductions in fiber digestibility by a physical coating action on feed particles. • Fats also have an inhibitory effect on rumen microbes; unsaturated fatty acids are toxic to rumen bacteria. • Fatty acids are neutralized at the rumen pH and converted to soaps, which are salts of fatty acids. • Potassium soaps are readily absorbed in the small intestine, whereas calcium soaps have lower absorbability. • Ruminants secrete a high proportion of taurine-conjugated bile acids, which facilitates solubilization of fatty acids in the acidic duodenum of ruminants. • In ruminants, the majority of lipid entering the small intestine is in the form of FFAs (80-90%) in contrast to non-ruminants, in which most lipid is in the esterified form. • One of the microbial transformations of lipids in the rumen is the synthesis of odd and branched chain fatty acids, which aid in maintaining optimal fluidity of microbial cell membranes. • The main fatty acid in mixed rumen bacteria is stearic acid, whereas palmitic acid is predominant in protozoa. • Protozoa contain a greater proportion of unsaturated fatty acids and CLA than do bacteria.

Lipids Structure 1. Fatty Acids

• The properties of a particular fat or oil are determined by the fatty acids they contain. • Fatty acids differ in the number of carbons atoms and in the amount of hydrogen they contain. • Those which are fully saturated with hydrogen are called saturated fatty acids, while the insaturated fatty acids contain one or more carbon-carbon double bonds that are not saturated with hydrogen. • Fatty acids contain a carboxyl group (-COOH) at the of carbon chain. • Fat contain mainly saturated fatty acids and are solids at room temperature. • Oils that contains insaturated fatty acids are liquids at room temperature. • The short-chain fatty acids (SCFA), such as acetic, propionic and butyric acids, are the VFA of rumen fermentation and are not generally viewed as lipids, as they are water soluble. • Unsaturated fatty acids may be either monounsaturated fatty acids (MUFA) or polyunsaturated fatty acids (PUFA). MUFA have one double bond, while PUFA have two or more double bonds.

Factors Affecting Feed Intake

• The regulation of feed intake and appetite is a complex subject. • Maximal feed intake can be achieved only with free choice and water available. When water is restricted, feed intake is reduced. • If a group or pen of animals goes off feed, the first thing to check is the water supply. • Large amounts of water are required to moisten food in the gut, especially in herbivores. • Ingredients with high water-absorbing properties, such as bran, increase the water requirements. 1- Palatability and Feed Preference 2- Dietary Energy Level 3- Protein and Amino Acid Concentration 4- Minerals 5- Forage Composition 6- Environmental Temperature 7- Pregnancy and Lactation 8- Learning and Conditioning 9- Metabolic Body Size 10- Other Factors.

Calcium and Phosphorus

• The requirements and metabolism of calcium, phosphorus and vitamin D are closely interrelated. • Bone mineral consists mainly of tricalcium phosphate and other salts of these two minerals. • Approximately 99% of the calcium and 80% of the phosphorus in the animal body occur in the bones and teeth. • Phosphorus is very important in cellular metabolism. • Many of the intermediates of carbohydrate metabolism are phosphorylated (e.g. glucose-6- phosphate, fructose-1,6-diphosphate and phosphoglyceric acid). • The central compound in energy metabolism, adenosine triphosphate (ATP), is a phosphorylated compound. • DNA and RNA contain phosphorylated pentose sugars. • Thus, reactions involving phosphorus are crucial to animal metabolism. • A number of critical metabolic enzymes are regulated by calcium and/or phosphorylation, including: - glycogen synthase, - pyruvate kinase, - pyruvate carboxylase, - glycerol-3-phosphate dehydrogenase, - pyruvate dehydrogenase. • Calcium and/or phosphorus deficiency symptoms reflect the metabolic functions of these nutrients as well as vitamin D. • Vitamin D is functional in calcium and phosphorus absorption, and in bone mineralization.

Acquired (adaptive) immunity

• The second arm of the immune system is termed the 'adaptive system' and is characterized by the production of antibodies which are directed against specific antigens. • The use of vaccines to protect animals from various pathogens is an example of acquired immunity. • Acquired immunity can be classified as either: - Cell-mediated; - Humoral immunity. • Cell-mediated immunity represents the immunological response associated with immune cells which act directly against pathogeninfected cells. • Humoral immunity on the other hand involves the generation of specific antibodies that are directed against the invading pathogens.

The Thyroid Hormones - Major Integrators of Metabolism

• The thyroid gland produces several thyroid hormones (THs) that have many important roles in virtually all aspects of animal metabolism. • The major THs are thyroxine (T4), also referred to as tetraiodothyronine, and triiodothyronine (T3). • T4 is synthesized in the thyroid gland, and released into the circulation. T4 is converted into the metabolically active form, T3, in the tissues. • Numerous plants contain thyroid inhibitors, or goitrogens. • Plants in the cabbage family (genus Brassica) are particularly noteworthy for their goitrogenic activity. • Brassicas contain sulfur-containing compounds called glucosinolates. Derivatives of glucosinolates, such as thiocyanates and isothiocyanates, are goitrogens. • These compounds inhibit the uptake of iodine by the thyroid. The shortage of iodine in the gland impairs production of THs, causing the thyroid gland to enlarge (goitre). Causes of goitre include either a dietary deficiency of iodine, presence of goitrogens or a combination of both.

Ruminant Wild Diets

• There are considerable differences in the lipid composition of wild ruminants compared to modern sheep and cattle. • Wild ruminants are generally much leaner, having lower quantities of depot fat and intramuscular fat (marbling). • A greater proportion of the tissue lipid of wild ruminants consists of structural lipids such as phospholipids in cell membranes.

Polyphenolic Antioxidants

• There is a great deal of interest in polyphenolics in fruits and vegetables. • They are believed to have beneficial effects on human health by functioning as tissue antioxidants. • Phenolic compounds contain aromatic rings with hydroxyl groups. • Polyphenolics have more than one hydroxyl group. • These phenolic groups function as antioxidants by providing hydrogen to reduce oxidants (Note that this is how vitamin E functions). • An example of a phenolic antioxidant is resveratrol

β-carotene Roles in Reproduction

• There is evidence that β-carotene may play a role in reproduction. • The corpus luteum of cows contains high concentrations of β-carotene, an observation which has stimulated research on its effects on dairy cow reproduction.

Sodium, Potassium, and Chloride Minerals

• These 3 minerals works together with phosphate ions, and bicarbonate ions. • Regulate the osmotic pressure and acid-basic homeostasis. • Control in the absorption of nutrients in the cells, and the metabolism of water.

Type 1 Diabetes

• This type occurs most often in childhood, and was formerly called juvenile-onset diabetes or insulin - dependent diabetes mellitus. • Type 1 diabetes is an autoimmune disorder; the immune system produces antibodies that attack and destroy the insulin-producing (beta-cells of the pancreas. • Loss of (beta-cells results in a lack of insulin production), leading to the onset of the signs of diabetes. • These signs include extreme: - thirst, - hunger, - frequent urination - fatigue. • These symptoms are all a result of elevated blood glucose.

Vitamin D Function and Deficiency

• Two forms of Vitamin D: - Ergocalciferol (D2, in plants tissue) - Cholecalciferol (D3, in animal tissues) Function: - The major biologic function of vitamin D is to maintain normal blood levels of calcium and phosphorus - Vitamin D aids in the absorption of calcium, helping to form and maintain strong bones - it promotes bone mineralization in concert with a number of other vitamins, minerals, and hormones - it maintains normal cellular growth and function - it maintains healthy immune function and preventing excessive inflammation - it inhibits parathyroid hormone secretion from the parathyroid gland • Deficiency: - Birds: rickets, eggs with bad shells - Mammals: rickets, enlargement of metacarpal and metatarsal bones, and other deformities in bones.

Osteoblasts and Osteoclasts

• Two types of cells, osteoblasts and osteoclasts, are important in the remodeling process. Osteoblasts - function in bone formation Osteoclasts - responsible for bone mobilization

Vitamin A Roles in Reproduction

• Vitamin A is essential for reproductive function in both males and females, and for fetal development. • Vitamin A deficiency results in weak, dead or malformed offspring. • There is evidence that vitamin A functions in steroidogenesis (synthesis of steroid hormones) such as progesterone. • Vitamin A may also have a direct effect on the uterine environment, including formation of normal uterine epithelial tissue. • Vitamin A also affects embryo development by regulating cell differentiation and proliferation. • In the male, vitamin A is required for spermatogenesis. • Hypervitaminosis A can also cause reproductive problems, including abortion, fetal resorption, birth defects and low neonatal viability.

Vitamin C as an Antioxidant

• Vitamin C, or ascorbic acid, functions as an antioxidant, in addition to its role in vitamin E recycling. • Its synthesis involves formation of L-gulonolactone from glucose, which is converted to ascorbic acid by the enzyme L-gulonolactone oxidase. • Most animals have this enzyme. A few, including humans, other primates, guinea pigs, fruit-eating bats, some fruit-eating birds and some fish lack this enzyme and so have a dietary requirement for vitamin C. • Besides its role as an antioxidant, ascorbic acid is also required in collagen synthesis.

Vitamin D

• Vitamin D is aptly known as 'the sunshine vitamin'. • It is formed by the irradiation of sterols in plants and in the skin of animals. Vitamin D occurs in two major forms: - (i) vitamin D2 (ergo- calciferol); - (ii) vitamin D3 (cholecalciferol). - Ergocalciferol is activated plant sterol; - Cholecalciferol is activated animal sterol. • Animals kept in total confinement, as is the case in modern pig and poultry facilities, are not exposed to sunlight and will require a dietary source of vitamin D. • Grazing animals exposed to sunlight normally do not require supplementation with vitamin D. • In the winter in northern climates, the amount and intensity of sunlight is often too low for adequate synthesis of vitamin D in the skin, and provision of a supplement is recommended. • In all animals, vitamin D2 is converted to D3 , with D3 being the metabolically active form. The efficiency of conversion is very low in poultry. • Although commonly classified as a vitamin, vitamin D actually functions as a steroid hormone. • It meets the criteria for a hormone. • The hormonal form is the hydroxylated compound, 1,25- dihydroxyvitaminD3 . • It is produced in a gland (the kidney) and is transported by the blood to the target tissue (the intestine). • Its formation and secretion are controlled by a feedback mechanism (blood calcium concentration). • The major physiological role of vitamin D is to regulate the absorption of calcium from the intestine, by regulating the mucosal synthesis of calcium-binding protein (calbindin). • There are some interesting differences among species in vitamin D regulation of calcium absorption, reflecting evolutionary background. - For example, llamas have a high dietary vitamin D requirement because in their native habitat at high elevations in the Andes, they are exposed to intense solar radiation.

Vitamin E and selenium

• Vitamin E and selenium play overlapping and essential roles in support of the immune system in ruminant animals. • A large portion of the benefits of these nutrients is related to their functions as antioxidants. • Feeding supplementary selenium to ruminant animals reduces incidence of diseases (including intra-mammary infections) and several studies have identified potential mechanisms

Vitamin E

• Vitamin E is a group of eight fat soluble compounds that include four tocopherols and four tocotrienols. • Vitamin E deficiency, which is rare and usually due to an underlying problem with digesting dietary fat rather than from a diet low in vitamin E. • Deficiency: • Birds: encephalomalacia, exudative diatheses (severe edema of the subcutaneous tissues), muscular dystrophy. • Swine: Exudative diatheses, Muscular degeneration, liver necrosis. • Bovines: Fetal reabsorption, Metritis, testicular degeneration.

Vitamin K

• Vitamin K is a group of structurally similar, fat-soluble vitamins found in foods and in dietary supplements. • The human body requires vitamin K for complete synthesis of certain proteins that are needed for blood coagulation or for controlling binding of calcium in bones and other tissues. • In allo-enzymatic animals the synthesis is in the rumen, by the bacteria. • In auto-enzymatic animals the synthesis is in the large intestine. In that case only can be used if exist coprophagy. • Deficiency: problems with blood coagulation.

7 - Pregnancy and Lactation

• Voluntary feed intake shows characteristic changes in pregnancy and lactation. • In late gestation, feed intake decreases, perhaps an effect of the high levels of circulating estrogens at that time that may alter metabolism to reduce energy requirements. • During peak lactation, feed intake is very high, to support high levels of milk production. • In dairy cattle, the peak in feed intake is reached after peak lactation occurs, so body reserves are mobilized during this period.

Energy usage and immune responses

• While activation of physiological processes within the animal in response to an immunological challenge is necessary for survival, there is an associated energy cost which reduces the overall productivity potential. • Indeed, creating and maintaining a febrile response alone is very energy intensive. • It has been estimated that there is approximately a 10-15% increase in energy usage for every degree of body temperature increase associated with an immune response.

Osteoporosis

• a bone disorder, in which the bone mass decreases, although its mineral composition is normal. Osteoporosis is common in elderly women.