Importance of protein in the diet of dogs

Protein is important dietary constituent not only for humans but also for our canine friends. Right amount of protein in your dog’s diet will help in the well-being of your dog.
Dr H S Madhusudhan
Proteins are complex molecules containing chains of subunits called amino acids. All proteins are basically made up of carbon, hydrogen and oxygen but unlike carbohydrates they always contain nitrogen. Although about 20 amino acids used in the composition of proteins, they can be arranged in various sequences to attain number of proteins, which we can observe in nature. The dog’s body cannot synthesize 10 specific amino acids arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine which are needed for optimum performance. They are called essential amino acids.
These amino acids have to be supplied in the form of dietary proteins. If a single essential amino acid is missing in the diet, it will lead to decrease in the food intake, which is known to be neuroresponse caused by the lack of limiting essential amino acid. Unlike cats, taurine is synthesised in dogs, so no need to supplement taurine in the diet of dogs. The non-essential amino acids can be made from excesses of certain other dietary amino acids.
What are the functions of protein in the body?
The amino acids supplied in the diet reform themselves into new proteins, which perform the following functions:

• Proteins are basically required for maintaining the structure of the body i.e. for optimum body condition of the dog. They are vital to cell division that is necessary for growth, reproduction and repair of tissues.
• Proteins in the form of enzymes and hormones regulate the metabolic processes in the body.
• Proteins aid in the formation of antibodies that enable the body to fight infection.
• Amino acids in the form of plasma proteins and hemoglobin play a major role in maintenance of normal physiology of blood circulation.
• Fibrous proteins like collagen are needed as connective tissues.
• Proteins play a major role in immune system.
• They can be stored as fat and during starvation they are burned as calories and serve as a major energy supplier.
• Proteins help to transport other nutrients around the body by binding them and then releasing when and where they are needed.
• Protein helps to regulate and maintain a proper fluid balance, which helps to maintain proper blood pressure and even lubricates the eyes.

 
How much protein does dog require?
The requirement of protein varies in different life stages of dogs, especially during rapidly growing and elder dogs with compromising kidneys. Pregnant and lactating dogs may need to be fed similar to growing puppies to give them the necessary protein. The hardworking dogs such as sled dogs in hilly areas, race dogs, hunting dogs, military and police dogs require extra protein in their diet. The recommended levels of protein for different life stages of dogs are as follows:
How to judge the quality of protein?
The proprtion of dietary protein which can be utilised by the animal for synthesising body tissues and compounds is measured as biological value (BV). Egg has the highest biological value (98) and other proteins are judged keeping the ‘egg’ as standard. Fish meal has 80, milk has 96, beef has around 78, soybean meal has 70, whole wheat has 67, Meat and bone meal are around 50, corn has 60, maize has 55 and peas have 63. Even though hair and feathers would be very high in protein, BV of these things is very low since their digestibility and availability to the body is very less.
To meet the minimum daily requirement, many dog foods use vegetable proteins which are harder to digest than animal proteins. Since animal proteins have higher BV than vegetable proteins and basically the dogs are carnivores, it is better to find a dog food with animal protein. Many dogs are allergic to grains like corn, wheat and soy found in dog food. So, care should be taken while selecting the source of protein i.e. we should avoid the food ingredient to which our dogs usually show allergic symptoms.
What happens if we feed too much protein to our dog?
If we feed too much protein to a healthy dog, some amount of protein gets excreted in the urine and the rest of them gets used as calories or is converted to fat and does not cause any harm. High protein diets are used for show or working dogs and a normal dog could become jittery and hyper on this type of diet. If the dog is suffering from kidney problem, high protein diet is not recommended. Moreover, protein is the most expensive ingredient in the food and there is no need to pay for more than we need.
(Dr H S Madhusudhan is PhD Scholar (Animal Nutrition) at Veterinary College, KVAFSU, Hebbal, Bangalore)