Posted: March 1, 2011, 5 a.m. EST
© Ferret Bandit/Courtesy Maddie George
Ferrets have much different dietary needs from dogs and cats.
Ferrets are an obligate carnivore, which means they require a meat-based diet in order to survive. Ferrets are also evolutionarily designed to eat a meat-based diet. Ferrets have a simple gastrointestinal tract and a unique physiology.
Ferrets have a short intestinal tract. They also have a rapid transit-time through the intestines. It usually takes only three to four hours for food to go from the mouth to the litter box. This makes the ferret’s digestive tract inefficient. To make things even worse, ferrets have a simple gut flora, minimal brush border enzymes and lack a cecum. This means ferrets cannot digest fiber, starch or other complex carbohydrates. To make up for this inefficient digestive tract, ferrets need a diet with a high level of protein, a high level of fat, a very low level of fiber, and a very low level of carbohydrates.
Ferret Protein Musts
Protein is the basic structural component of all of the tissues in the body, and protein is required for growth and to maintain normal tissues in the body. Protein is made up of amino acids, and approximately 24 amino acids are found in animal tissue. Ferrets require a high protein level (35 to 55 percent). This is higher than requirements for cats and dogs. The protein must be high-quality, meat-based protein to meet their requirements for the essential amino acids.
Deficiencies in certain amino acids can cause serious problems. Taurine is required for normal heart muscle and eye function. A diet that does not have enough taurine can cause the heart to stretch and enlarge (dilated cardiomyopathy). This can lead to congestive heart failure and death. In the eye, a low taurine diet can cause blindness from central retinal degeneration. Taurine is present in poultry and fish, and most commercial ferret diets add extra taurine to the diet. In some countries, such as Australia, some working ferrets are fed homemade diets with rabbit, lamb and kangaroo meat as the main ingredients. Rabbit, lamb and kangaroo meat can have a low taurine content, so a taurine supplement might be required to prevent taurine deficiency problems.
The amino acids methionine and cystine are also important for good health. These two amino acids contain sulfur. When they are digested, the sulfur is converted to sulfuric acid. The sulfuric acid is eliminated through the kidneys and into the urine. This acidifies the urine and prevents bladder infections and struvite bladder stones. Protein from plants such as corn gluten, wheat gluten, soybean meal and soy protein isolates do not contain these sulfur-containing amino acids. Diets high in plant-based protein will raise the pH of the urine, which can cause struvite bladder stones. Fortunately most commercial ferret diets have dl-methionine added to acidify the urine.
Why Ferrets Need Fat
Fat is important in the ferret diet for several reasons. Fat contains 2.25 times the energy of protein or carbohydrates, so it is a highly concentrated source of energy for ferrets. Fat also contains the essential fatty acids linoleic, linolenic and arachidonic. These fatty acids are needed for normal skin and hair coat.
Fat also contains the fat-soluble vitamins A, D, E and K. Vitamin-A deficiency can cause stunted growth, night blindness and muscular incoordination of the rear legs. Vitamin-D deficiency can cause abnormal bone development. Vitamin-E deficiency can cause anemia, anorexia, a weak immune system, an impaired gait and paralysis. Vitamin-K deficiency can create problems with blood clots that can lead to bleeding problems. Most commercial ferret diets have a fat level of 20 to 30 percent, which should prevent these problems. In addition to the fat-soluble vitamins, most commercial ferret diets include the water-soluble B vitamins.