Protein

Protein Requirements Species and Growth Stage Puppy Adult dog Performance dog Racing sled dog Lactating dog

28% / 17% 18% / 9-15% 25% / 20% 35% / 50% 28% / 17%

Complete Protein

Means that it contains all required amino acids. (eq. chicken and chicken by-product meal).

Debate Point

Can you feed too much protein? Cats and dogs have a high ability to digest protein. But the concern is if more protein than the animal can use is fed, the by-products are excreted through the kidneys, possibly damaging them. (Not proven). Probably what is more concerning is whether the entire diet is balanced, and if the total calories are correct.

Cat Note

Cats do not have the ability to adequately synthesize one amino acid that dogs can - taurine. A cat food will contain more taurine than a dog food, and this may be indicated on the label. This is one reason why cats should not be fed dog food. Extra taurine does not harm a dog. In cats, a taurine deficiency can lead to weak heart muscles or retinal degeneration. Taurine can be derived from chicken and chicken by-products. If the diet has high vegetable protein, then taurine is usually added by the cat food manufacturer.

Protein Quality

Every protein source contains different levels of amino acids and each protein is different in its ability to be broken down into amino acids. So not all proteins are created equal. Some are better for pets than others. The ability of a protein to be used by the body and its amount of usable amino acids is summarized as protein quality (biological value). Egg has the highest biological value and sets the standard for which other proteins are judged. Egg has a biological value of 100. Fish meal and milk are close behind with a value of 92. Beef is around 78 and soybean meal is 67. Meat and bonemeal and wheat are around 50 and corn is 45. Things like hair and feathers would be very high in protein but would be down at the bottom of the list for biological value. There is good and poor quality protein. Cheap prices = cheap quality. Expensive food with the right ingredients and the right amount (don't need to feed as much) are advised.

Digestibility Ranking or Biological Value

Meat protein is highly digestible. Corn, wheat and other plant types aren't always good sources of protein because they can't always be digested properly. Pre-digested (hoe it was produced) products can be given to cats. Egg, chicken/fish, chicken by-product meal, meat, meat and bone meal, soy, corn. Eggs are the best thing to digest.Has a biological value of 100%. Beef is only 78%. May also be called "Biological Value" = amount that can be absorbed. Protein digestibility - good food from 80-90%; low quality foods less than 75%. A protein with a very low biological value is almost entirely excreted by the body as waste after ingestion. To evaluate the protein levels of different dog foods, two factors should be considered. One is the level of protein and the other is the protein digestibility, or availability of the protein to a dog, which can be determined only by controlled feeding studies. Animals can have increased protein requirements: - during growth - during tissue repair or convalescence - during pregnancy and lactation - as working dogs Protein helps with palatability and flavour. Excess amino acids are stored as fat or glycogen. True protein quality can only be determined by long term use and a dog doing well on that source of protein in its food. A requirement is the food needs to be highly digestible. Different life stages require different amounts of protein. The body can't handle too much protein - so excess protein may be changed into glucose or fat and stored. There are different protein sources put into pet foods - plant or meat. Combinations of different sources can provide all essential amino acids.

Signs of Protein Deficiency

Muscle loss, poor hair condition, lethargy, reduced resistance to infectious diseases, slow growth, weight loss, lower reproductive performance, and decreased milk production. Cats fed dog food can have this, as well as taurine deficiency. Protein is an essential nutrient. Dogs fed diets too low in dietary protein may develop signs of deficiency. Dogs can also experience subclinical protein deficiencies. In such a condition, they may appear perfectly healthy, yet they may be more susceptible to infections and other environmental stresses. Lack of protein most likely becomes evident when being fed a weight loss food (or less of a regular diet) or on a protein-restricted kidney diet. Proteins - animal or plant proteins are common causes of food allergies. Cats can not eat dog food - because there is no Taurine and there are not enough nutrients - they will not do well or survive.

Sources of Protein

Protein is derived from both animal and plant sources. Most protein ingredients contain inadequate amounts of one or more amino acids and are thus inefficient if used as the sole source for meeting protein needs. However, by careful selection and combination of different protein sources, these inefficiencies can be completely overcome. For example, soybean meal and corn complement each other perfectly, because the amino acids which are deficient in one are present in the other. Neither meat nor soybean meal is an ideal source of protein; however, either can be adequate if fed in combination with another complementary source of amino acids. By-products are actually excellent sources of nutrients for pets.

Overview

Proteins are large molecules formed of smaller units called amino acids.Protein is very important in the body as building blocks of tissue including muscle growth and tissue repair (or also called structural components), hormones, enzymes, transporting oxygen in the blood and the immune system. They are essential for repair and growth. Are also an important source of calories (energy). Some amino acids cannot be synthesized in the body, and must be provided nutritionally - these are called essential amino acids. Essential amino acids are those that cannot be formed fast enough or in sufficient amounts to meet the requirements for growth and maintenance and, therefore, must be supplied in the diet. A food must provide the animal's entire protein need, as well as the proper amounts of the essential amino acids (in an accessible form). Conversely, non-essential amino acids CAN be synthesized by the body. The body either makes proteins or requires you to put them in your diet.

Protein Requirements For Good Nutrition

Proteins are the building blocks in animal nutrition. They are one of the most important nutrients in the diet and are currently one of the most widely debated. At the center of debate for pet foods is protein, its source, digestibility, and quantity. For around twenty thousand years as dogs, and for several million years before that as wolves, the only problem canines had with protein was getting enough of it. Dogs ate a primarily meat diet and with that consumed a high percentage of their diet as protein. With their meat diet they also got a fair portion of fat and a little fiber and carbohydrate thrown in, but primarily they ate meat. Cats were pretty much the same only they were even stricter carnivores and did not eat any carbohydrates. Protein requirements vary from species to species and can vary greatly during the rapid growth stages and for elderly animals with compromised kidneys. Pregnant and lactating dogs may need to be fed puppy chow to give them the necessary protein. Sick, weak, and debilitated animals also need extra protein. Animals with kidney disease may need to be on a protein-restricted, but high biological value diet to lessen the effects of the kidney disease.

Complete & Incomplete Proteins

These proteins can be combined with other nutrient amino acids to form the required protein. Food proteins don't have the exact amino acid requirements for cats and dogs, so protein mixtures are used. The quality and digestibility of protein varies greatly - ie hair or leather vs. egg or chicken. This cannot be entirely determined by reading a label. But generally animal protein is more digestible than plant proteins. And more expensive products will contain better quality proteins.

Incomplete Protein

Those lacking in one or more of the required amino acids. These proteins can be combined with other nutrient amino acids to form the required protein. Food proteins don't have the exact amino acid requirements for cats and dogs, so protein mixtures are used. The food source doesn't have all required amino acids.

Essential Amino Acids

Those that cannot be manufactured in sufficient quantity by the liver and must be present in food. Dogs and cats require all of the same amino acids in their food with the exception of taurine. Taurine is essential for cats but not for dogs. Cat's don't do well without Taurine. Chicken is an excellent source of Taurine in the diet. Even if a type of cat food is chicken, extra taurine is still added. A protein is defined as a group of amino acids linked to each other in different quantities and sequences. Each protein has a precise combination of amino acids that is specific for that protein, and the arrangement of amino acids determines the specific nature of a protein. Dietary protein that is digested in the stomach and small intestine is broken down to form free amino acids which are then absorbed into the bloodstream. Amino acids are distributed to various cells of the body where they are utilized to build body proteins. There are millions of combinations/sequences of amino acids. A linear sequence of Amino Acids make up a particular protein. - Arginine - Phenylalanine - Histidine - Tyrosine - Isoleucine - Threonine - Leucine - Tryptophan - Lysine - Valine - Methionine - Taurine (cats only) - Cystine

Amino Acids

Why do dogs and cats need protein? Proteins are necessary for all aspects of growth and development and are very important in structural make up and the immune system. In addition, they are burned as calories and can be converted to and stored as fat. In reality, pets do not need the protein but they need the building blocks that make up the protein, amino acids. There are 22 amino acids that animals need. Animals can synthesize 12 of them - the rest have to be in the diet. The remaining ones must be consumed. The ones that the animals cannot synthesize are called essential amino acids. They are arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valin, and in cats, taurine. Dogs can synthesize taurine, and therefore, it is not supplemented in their food. This is why there is the old adage that dogs can eat cat food but cats cannot eat dog food.