Nutritional Management and Congenital Defects of Exotic Felidae

Symposium on Advances in Feline Medicine I

Nutritional Management and Congenital Defects of Exotic Felidae Michael T. Walsh, D.V.M.*

DIETARY MANAGEMENT OF EXOTIC FELIDAE Exotic feline nutrition has lagged behind that of the domestic cat in product availability, palatability, and owner acceptance. When adVising the exotic cat owner on dietary needs, it is often easiest to recommend that the animal be put on a commercial product such as Zu/Preem. t What the practitioner must realize is that a dietary change may be more traumatic for the owner than for the cat. There is often a period of nonacceptance of a new diet by the cat so that the owner perceives the animal to be "starving." Now that the owner has been convinced to switch to a diet that the cat will not eat, the owner will be ever more steadfast in avoiding dietary change and may lose confidence in the veterinarian. Open, honest communication between the veterinarian and the owner will help to maintain a working relationship, but the veterinarian should be able to offer alternatives to a complete diet change. Often a diet may only require supplementation to be fairly complete and still be accepted by the owner. In the past, the most common diets fed to cats were organ-meat-based. This was a traditional diet that was often passed from seller to buyer or from generation to generation of breeders. This diet will be discussed with others in the following sections. A great deal has been written on feline nutrition in the last 40 years. 22. 42, 47, 48 In 1964, Patricia Scott addressed the general nutritional requirements and deficiencies of the domestic cat. Further work has provided a clearer understanding of many dietary requirements.6, 18, 28, 30, 31, 38 Malnutrition can occur at any stage in the life span of a cat and may influence many aspects of growth, maintenance, and reproduction such as in utero development, litter size, and postnatal care. An adult on a deficient *Resident, Department of Special Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, Florida tZu/Preem. Hills Pet Products, Inc., Topeka, Kansas. Veterinary Clinics of North America: S11Ulll Ani11Ul1 Practice-Vol. 14, No.5, September 1984

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diet may only show a decrease in vigor or life span . It has been shown that the immune response is closely tied to the nutritional status of an animal. 43 Water Requirements As with all animals, water is the most essential dietary ingredient. Requirements may range from 44 to 88 ml per kg per day.42 The need for supplementation will fluctuate widely based on the water content of the food source, activity, temperature, and so on. A fresh, renewable water source should be provided at all times. Caloric Needs The energy requirements of a cat can be supplied by proteins, fats, and carbohydrates. An adult cat may require approximately 30 kcal per pound of body weight per day, whereas a kitten's needs may be three to five times that amount. 12 The actual daily requirements may be higher depending on the energy required for warmth, activity, lactation, and so on. Protein requirements for the cat differ from that of the dog in that a higher proportion of the caloric needs should be provided as protein. lO • 13.27.38 On a dry weight basis, kittens may require 16 to 32 per cent and adults up to 21 per cent of the diet as protein. The lower requirement of protein for kittens may be satisfactory if all the amino acid requirements are met. 3. 27 This high requirement is necessary because the cat has a limited capacity to conserve essential amino acids and nitrogen. 37. 38 Protein needs can also be approximated by providing 5 g per kilogram per day for an adult.41 Later research has concentrated on the specific amino acid requirements of the domestic cat. 1. 29, 36, 38 The cat is the only mammal known to require taurine, an essential amino acid. In most animals, cysteine and methionine are largely converted to taurine, whereas in the cat they are converted to felinine .6, 38 As a result, diets fashioned for other species from bovine milk sources may be very deficient in taurine, leading to retinal degeneration and blindness. Taurine also has a regulatory effect on cardiac muscle and nervous tissue and has been used in preliminary experiments as a treatment of epileptic seizures in humans. 6 Arginine is another important essential amino acid for the cat and its absence from one meal can lead to NH3 intoxication and death. Table 1 lists the other important amino acids of the cat. There is some disagreement as to the number of essential amino acids in the cat, with the number ranging from 11 to 13. 1. 6. 36. 38 Table 1. Essential Amino Acids of the Cat 6 . 37. 38 Arginine Cysteine Histidine Isoleucine Methionine Leucine Lysine

Phenylalinine Taurine Threonine Tryptophane Tyrosine Valine

NUTRITIONAL AND CONGENITAL PROBLEMS OF EXOTIC FELIDAE

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The dietary requirement for fats is not as well established. Research on the essential fatty acids of cats has been somewhat behind when compared to research conducted on other food groups. There is evidence to suggest that deficiencies in dietary fatty acids result in the same clinical syndromes in cats that are seen in other species. 33 Essential fatty acid deficiencies can occur with diets that contain vegetable oils as the only source of fats . Cats can utilize a large percentage of their diet as fat, but unsaturated fats such as those found in red tuna or rancid oils may result in steatitis . Fats and proteins are used to make a feline diet palatable. Carbohydrates are not a necessary requirement for a feline diet but can be well utilized.6. 22 Lactose and sucrose do not appear to be as well tolerated as polysaccharides, and diets containing cow's milk or whey, which are both high in lactose, may lead to diarrhea in some individuals .41 Vitamins Dietary vitamin needs of the domestic cat have received more attention than those of exotic cats, but they are likely to be very similar. Cats can not synthesize vitamin A from beta carotene, so they are dependent on a dietary form .6. 30. 41 The domestic cat requires 160 to 200 units per pound of body weight of vitamin A.41 It was found that adding 100 units of vitamin A per pound of body weight to the diets of exotic cats at a zoological park in England raised their liver vitamin A levels to near normal. 16 Another peculiarity in feline vitamin needs is that of a need for niacin supplementation. Although most animals synthesize niacin from tryptophan , the cat catabolizes tryptophan in an alternate pathway. Thiamine also merits some attention, because the cat has a fairly high requirement for this water soluble vitamin. Thiamine can be destroyed by the canning process (overheating), by thiaminase (present in some fish), and by sulfur dioxide (used as a preservative). Signs of thiamine defiCiency are listed in Table 2. Treatment with 1.1 to 2.2 mg per kg of thiamine will usually result in a rapid recovery in less than 24 hours. Recent work has suggested that there are at least three different manifestations of thiamine deficiency-an acute dietary form, a chronic dietary form, and a familial dependency. Although all three types have similar clinical signs, the familial form (as seen in one family of cats) is controlled only by daily megadoses of thiamine. 26 Symptoms associated with pyridoxine (B6)' and riboflavin (B 2), as well as pantothenic acid, choline, and folic acid are listed in Table 2. Mineral Components Sodium and potassium requirements are given in Table 3. Calcium , defiCiency is fairly common in cats on an all-meat diet. Nutritional secondary hyperparathyroidism is most common in younger animals, in which there is a greater requirement for calcium during growth. If the cat is suckling, the burden is often shifted to the mother until the cat is weaned. Adult cats can suffer the same problems if they are on an all-meat diet for an extended period. The clinical signs of defiCiency can range from muscular cramps to pathologic fractures, and serum calcium levels may not reflect the animal's true calcium status. The phosphorus content of all-meat diets is extremely high, as seen in Table 3. Both magnesium and phosphorus are

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Table 2. Deficiencies Associated with Common Clinical Signs PANTOTHENIC CLINICAL SICNS

A

BI

BZ

X X

X X X

X X

Anemia Anorexia

Weight loss Vomiting Diarrhea Cataracts Conjunctivitis Corneal changes Retinal degeneration Photophobia Testicular atrophy Fe tal death Stillborn Weak birth Skeletal deformities (skull) Rickets Weakness Ataxia Tremors

Paralysis Convulsions Polyneuritis Neck ventroflexion Oral ulceration Protruding claws Squamous metaplasia Urolithiasis Steatitis Fatty liver Liver necrosis Poor coat

BO

BIZ

NIACIN

ACID

CHOLINE

D

E

X

X X

FOLIC ACID

X X

X X

X

X

X

X X X X X X X X X X X X X X X

X X X X X X X X

X X X X X

X

X

X

X X X X

X X

X

X

X

important components of the ash content of the diet. Suggested levels for iodine, copper, and other minerals are listed in Table 3.

Diet Comparison Although the trend with zoos has been to shift to the use of commercial diets, there are still many individuals who insist that their cats do well on a total meat diet or a chicken neck diet. Table 3 compares the nutritional content of some of the older diets to a commercial diet, and to the needs of a small adult cat. The chicken neck diet supplemented with vitamins has a better calcium:phosphorus ratio than an all-meat diet but is deficient in its protein base and some B vitamins. Although this diet eliminates the secondary nutritional hyperparathyroidism seen with the organ-meat diets, its ash content is quite high, reaching 15 per cent or greater. A pure muscle meat diet is deficient in calcium, copper, iodine, vitamin A, and riboflavin, so even though energy requirements are better provided by the meat diets, there are obvious trade-offs. Table 4 illustrates the difference in the energy contents of the foods in Table 3. Often the choice of a diet is based on financial considerations. A diet consisting of whole animal components that is processed and prepared may

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NUTRITIONAL AND CONGENITAL PROBLEMS OF EXOTIC FELIDAE

Table 3. Comparison of Requirements of Small Cat to Ingredients of Common Diets (Per Pound) REQUIREMENT PER CAT Protein (a)t Protein (y):j: Energy (a)t Ca Phosphorus CalPhosphorus Vitamin A Vitamin D3 Vitamin E Vitamin C Vitamin B, Vitamin Bz Vitamin B. Vitamin B,z Niacin Choline Folic acid Na K Mg Fe Cu I Mn Zn Co % Ash

12-14% (wb)§ 14-16% 30 kcaVlb 0.3--0.5% 0.15% 1.2-1.5/1 2000 I. U. 50-100 I. U. 0.36--3.6 mg ? mg 0.4 mg 0.2 mg 0.2-0.3 mg 0.01 mg 2.6-4 mg 100 mg 0.002 mg 20-30 mg 80-200 mg 8-10 mg 5 mg 0.2 mg 0.07-0.2 mg 0.2? mg 0.25--0.3? mg 0.16? mg 4%

CHICKEN NECK WITH VIONATE*

BEEF HEART

HAMBURGER

ZU/PREEM

7.42%

20%

17.6%

16%

329 kcal 52 gm/lb 24 gm/lb 2/1 1700 104

490 kcal 23 885 1/38 90

1216 kcal 45 708 1116 160

1115 kcal 0.65% 0.35% 1.6/1 10,500 I. U. 485 I. U. 45

1134 0.29 0.9 0.04

9 2.42 3.98

0.35 0.72

7.8 27 mg 0.01

34.1

19.5

390 875

1070

18.1

12.2

3.24 7.0 1.8 0.09 35.5 662. 0.47 0.17% 0.23% 0.01% 79 mg 5 mg 0.09 mg 4.9 mg 17.3 mg 0.68 mg 4%

2.0 30 0.26 0.104 0.34 17%

Note: Dashed line indicates that item was not tested for. *Vionate. Rich Health Inc., Nutritional Research Lab, Irvine, California. ta = adult. :j:y = young. §wb = wet basis.

be too expensive for many small breeders. Some feed companies also have minimum purchase requirements, which makes bulk storage necessary and leads to some wastage. When the consulting veterinarian is not able to switch the diet to a commercial, balanced product, because of financial needs or personal prejudice, supplementation can be used to bolster a deficient diet. A chicken neck diet can be supplemented with a multiple vitamin mixture and a protein source. If meat is used as a protein source, Table 4. Weight of Cat Related to the Amount of Food (Pounds) Required to Supply Its Energy Needs (Pounds)* CAT'S WEIGHT 10 lb 100lb

ENERGY KCAL

ZU/PREEM

LEAN BEEF

CHICKEN NECKS

HAMBURGER (FAT PRESENT)

300 3000

.29 2.8

.49 5.0

.91 9.0

.25 2.5

*From Fowler, M. E.: Personal communication, 1984.

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Table 5. Comparison of Natural Milks with Milk Replacers

TYPE

Water Fat Protein Carbohydrates

DOMESTIC CAT'o

DOMESTIC

cow's WHOLE

(EARLY

(LATE

MILK

LACTATION)

LACTATION)

LEOPARDi!S

KMR

ESBILAC

80--82% 5.3% 7.5% 4.3%

80.6% 6.5% 11.1% 4.2%

82.0% 4.75% 7.5% 4.5%

85.0% 6.38% 5.0% 3.4%

87.0% 3.5% 3.5% 4.8%

80--82% 3.4% 4.0% 3.6%

CAT'°

then a calcium source such as calcium lactate, calcium gluconate, tricalcium phosphate, or bone meal (5 to 10 per cent of the diet) can be used to correct the calcium:phosphorus imbalance. If these calcium sources cannot be found, then calcium carbonate used at 0.5 to 1.5 g per 100 g of food will help to balance the calcium deficiency.41 It is important to note when a calcium product also contains vitamin D, because the total daily requirement for vitamin D is fairly low and may not require any additional supplementation. Neonatal Nutrition Many exotic neonates are removed from the mother at an early age in order to facilitate hand raising. This often presents a problem in choosing a reliable milk replacer and forces the neonate to rely on one unchanging formulation for maintenance and growth. In a study of domestic cat milk, the composition of the milk was monitored from parturition to greater than 43 days postpartum. It was found that the amount of protein, fat, carbohydrate, calcium, and manganese increased during the course of lactation. 20 As a result, some replacers may be deficient at different periods of lactation. With this in mind, comparisons between milk types should indicate the time of lactation when taken and the mother's diet, when possible. The three most common diets used are probably cow's milk, KMR* (kitten milk replacer), and Esbilact (bitches' milk replacer). Table 5 compares the replacement formulas to natural milks. There are disadvantages with each diet so that none are universally used by zoos or private breeders. Cow's milk is deficient in protein and in calories when used for a cat. Powdered cow's milk should be used at twice the normal strength or, if used at normal strength, it should be supplemented with a soluble protein and B vitamins. Diarrhea from lactose intolerance may result from the use of cow's milk. Esbilac is one of the more common replacements used. The major advantages with this product are that it is palatable and does not result in clinical diarrhea as often as the other choices. The major disadvantages are that it is low in protein and has been associated with cataract formation. Dietinduced cataracts have been linked to many amino acid deficiencies as well as to certain vitamin deficiencies. 22 There may be a critical period when the lens is more susceptible to deficiencies. Owners should be warned of *KMR liquid (powdered form available). Borden Inc., Pet-Ag Division, Elgin, Illinois. tEsbilac liqUid (powdered form available). Borden Inc., Pet-Ag Division, Elgin, Illinois.

NUTRITIONAL AND CONGENITAL PROBLEMS OF EXOTIC FELIDAE

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the possibility of cataract formation and protein deficiency when kittens are put on an Esbilac diet. KMR appears to be a more obvious choice as a milk replacer for exotic cats. The major disadvantage of this diet that is cited by breeders is its tendency to cause diarrhea. This can be very debilitating for a young cat that is also adjusting to the loss of its mother, and very disturbing to a new owner. Because any radical diet change can result in diarrhea, the owner should understand that a new diet should be introduced slowly to decrease this possibility. As a cow's milk derivative, KMR contains a high level of carbohydrates, the bulk of which is lactose. Initial lactose intolerance may be involved in the pathogenesis of this diarrhea. This effect can be decreased by diluting the liquid to a 50 per cent solution, which is increased over a few days time. Kaopectate has been used to aid in diarrhea control. 25 Proper sanitation of diet equipment will decrease the possibility of spoiled or contaminated food, which can also lead to diarrhea. It is during the weaning period that the owner should strive to acclimate the young animal to a balanced diet, rather than to have to readjust it once more. A variety of foods may be initially offered, but the emphasis should be on a balanced commercial diet when possible.

CONGENITAL DEFECTS IN EXOTIC FELIDAE A congenital defect is defined as a defect in structure and/or function present at birth. These defects may occur in only one system or may affect multiple body systems. The incidence of congenital defects in most populations is estimated at around 1 per cent or less. 23 This level of incidence is one that may be expected in populations that are not seriously handicapped by poor diet, mismanagement, or inadequate gene pools. The type and frequency of congenital problems in the exotic felidae is not well documented, although an excellent review of congenital defects of domestic cats was done by Saperstein et al. 39 The exotic populations available for study have usually consisted of those in zoos or those in private hands. Often the emphasis was not on reproduction but on simple maintenance of members of a species. Pedigree records were usually not kept, diets may have been deficient, and necropsies often were not done. As concern for species welfare has increased and wild populations are threatened with extinction, more attention has been given to the interrelationships of animal management and the causes of neonatal mortality. There are two major influences that may be responsible for congenital defects, inheritance, and environment. The genetic factors are best understood after first identifying a disease that is occurring in a familial pattern, detailing the relationship between related members of groups, then analyzing this relationship with controlled breeding trials to determine the mode of inheritance. Before this can be accomplished, the environmental factors must be controlled. Sound management practices should help to eliminate or control such factors as dietary deficiencies, temperature fluctuations, access to toxic materials, and so on. All of these factors may influence the degree to which an animal is affected, even if the problem has a genetic base.

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There is disagreement among investigators as to which conditions of the domestic cat are more common. Priester felt that the nervous system was most commonly affected, whereas Jude had felt that oral cavity and appendages were involved more. 19. 32 When all the species are viewed as one group, the central nervous system, skeletal system, and muscular system are the most frequently affected systems. 23 Saperstein listed defects in the domestic cat in the central nervous system; eye and ear; and musculoskeletal, circulatory, digestive, urinary, reproductive, and integument systems. He also noted hernias, defects in metabolism, congenital duplication, and chromosomal abnormalities. 39 It is not within the scope of this article to review all the presentations within each system. The reader is referred to the Saperstein article 39 for further details. Table 6 lists some of the previously reported congenital defects in exotic cats as well as some that have not been reported as of yet. This list does not include much of the later European data. Although some defects such as cleft palate have a fairly well established genetic basis, there is still some question as to the role of some nutrient deficiencies in the expression of some deformities . Vitamin A deficiencies have been implicated in heart and lung deformities as well as in diaphragmatic hernias, but it is not known to what degree the diet is at fault. It is hoped that this article will stimulate veterinarians to stress the need for good necropsies and the reporting of defects as well as the keeping of accurate breeding and diet records. Table 6. Congenital Defects of Exotic Cats DEFECTS

DESCRIPTION

SPECIES

Cleft palate

Nonclosure of palate

Lion ls Bengal tiger l7 Lion2l LionS

Aplasia of trachea Epstein's deformity Persistent ductus arteriosus Ventricular septal defect Diaphragmatic hernia Umbilical hernia Thymic hypoplasia Partial albinism Tail, kinked Tail, curled Ocular dermoid

Ocular colobomata

Cusps of tricuspid valve are fused, associated with foramen ovale

Protrusion of viscera through diaphragm Protrusion of viscera through abdominal wall at umbilical area Small fatty thymus White tigers Distal end of tail: affects last few vertebrae Tail curled about 3600 Full expression between 4-14 months Haired dermoids involving bulbar conjunctive and third eyelid Haired dermoid extending onto the cornea, associated with eyelid agenesis laterally

Lions Lions Cheetah3S Leopard l7 Bengal tiger' Bengal tiger7 Cheetah3S Siberian tiger" Bengal tiger"" 15. 24. Cheetah3S Florida panther? Cheetah3S Lion'" Geoffrey cat" Snow leopard'

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NUTRITIONAL AND CONGENITAL PROBLEMS OF EXOTIC FELIDAE

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31. Patton, R. S.: The effect of nutrition on reproduction in zoo animals. In Current Therapy in Theriogenology. Philadelphia, W. B. Saunders Co., 1980. 32. Priester, W. A., Glass, A. G., and Waggoner, N. S.: Congenital defects in domesticated animals: General considerations. Am. J. Vet. Res ., 31:1871-1879, 1970. 33. Rivers, J. P.: Essential fatty acids in cats. J. Small Anim. Pract., 23:563-576, 1982. 34. Robinson, M. S., and Benirschke, K.: Removal of a conjunctival dermoid in an African lion. J. ZOO Anim. Med., 12:8fr88, 1981. 35. Roelke, M. E.: Personal communication, 1984. 36. Rogers, Q. R., and Morris, J. G.: Essentiality of amino acids for the growing kitten. J. Nutr., 109:718-723, 1979. 37. Rogers, Q. R., and Morris, J. G.: Do cats really need more protein? J. Small Anim. Pract., 23:1-11, 1982. 38. Rogers, Q. R., and Morris, J. G. :Amino acid nutrition and metabolism in the cat. In Proceedings of the Kal Kan Symposium, 1977, pp. 6--12. 39. Saperstein, G. , Harris, S., and Leipold, H . W.: Congenital defects in domestic cats. Feline Pract., 7:18-43, 1976. 40. Saperstein, G., Leipold, H. W., and Kruckenberg, S. M.: Congenital defects of wild and zoo mammals. Inst. Lab. Anim. Res. News., 20:AI-A23, 1976. 41. Scott, P. P.: Nutrition of the cat. Vet. Rec., 72:6--9, 1960. 42. Scott, P. P.: Nutritional requirements and deficiencies. In Feline Medicine and Surgery. Santa Barbara, California, American Veterinary Publications, Inc., 1964, pp. 6~9. 43. ShellY, B. E., and Williams, A. J.: Nutrition and the immune response. J. Am. Vet. Med. Assoc., 180:1073-1076, 1982. 44. Thorton, I. W. B.. Yeung, K. K., and Sankhala, K. S.: The genetics of the white tigers of Rewa. J. Zoo!. [Lond.], 152:127-135, 1967. 45. Vainisi, S. J., Ed .. lhauser, H., Wolf, E. D.: Nutritional cataracts in timber wolves. J. Am. Vet. Med. Assoc., 179:1175-1180, 1983. 46. Wallach, J. D.: Nutritional diseases of exotic animals. J. Am. Vet. Assoc., 157:583-599, 1970. 47. Wallach, J. D.: Nutritional problems in zoos. In Proceedings of the Cornell Nutrition Conference, 1971, pp. 10-19. 48. Wackernagel, H.: Modern methods of feeding wild animals in zoological gardens. Basle, Switzerland, Hoffmann-La Roche and Co., 1961. Department of Special Clinical Sciences College of Veterinary Medicine University of Florida Gainesville, Florida 32610