Nutrient intake and influence on markers of oxidative stress in zoo-managed male snow leopards (Uncia uncia).

Oxidative stress (OS) results from the overproduction of reactive species. Nutrient intake can contribute positively or negatively to OS, and the lack of established nutrient requirements for most of the exotic species managed in zoos exacerbates the possibilities for nutrient imbalances that potentially could lead to reactive species production. The objective of this study was to evaluate the influence of nutrient intake and nutritional husbandry on markers of OS in male snow leopards (n = 14) maintained in U.S. facilities (n = 12). Diet samples and husbandry information were obtained and snow leopards were immobilized once for collection of blood. Samples were analyzed for chemical composition (diet and blood), antioxidant capacity (blood), and markers of OS (blood). Correlations between weekly nutrient intakes and markers of OS were analyzed by linear regression. Analyzed markers of OS included antioxidant enzymes (superoxide dismutase [SOD] and glutathione peroxidase [GPx]) and ferric reducing antioxidant potential that are protective against OS, and protein carbonyls, thiobarbituric acid reactive substances, and DNA/RNA damage that are indicative of oxidative damage. Weekly copper intake (10.1 to 80.2 mg) was negatively correlated with DNA/RNA damage (R 2 = 0.44; P = 0.01). Weekly sodium intake (4.4 to 12.7 g) was positively correlated with GPx activity (R 2 = 0.43; P = 0.04). More frequent feeding of whole prey (0.3 to 3 times/wk) was correlated with increased blood SOD activity (R 2 = 0.55; P < 0.01). In conclusion, greater dietary copper intake and more frequent feeding of whole prey may reduce OS in snow leopards. Dietary sodium intake and relationship with GPx activity should be further evaluated to determine benefit or detriment. No cause and effect can be inferred from our results, but our data suggest altering dietary form and nutrient concentrations may influence OS in snow leopards.

Factors affecting reproductive traits in male snow leopards (Unciauncia).

ABSTRACT: The population of snow leopards (Unciauncia) maintained in US zoos is no longer sustainable due to poor reproductive success. Our objective was to assess reproductive traits in male snow leopards and identify factors (markers of oxidative stress in seminal fluid, surveys of husbandry practices, gonadal and adrenocortical activity, dietary intake of various nutrients, and genetics) that may affect ejaculate traits and subsequent fertility. Ejaculates (2.9 ± 0.2 mL) from 32 male snow leopards (9.8 ± 0.7 years; 38.6 ± 0.8 kg) housed at 27 institutions contained 119.2 + 26.0 x 106 spermatozoa, of which 75.1 ± 2.3% were motile and 28.6 ± 2.6% exhibited normal morphology. Overall, 34% of males produced <5 million spermatozoa and 27% of males produced spermatozoa with <20% normal morphology. Activity of superoxide dismutase (SOD) in the seminal fluid was negatively correlated (P < 0.05, r2 = 0.90) with normal sperm morphology. Husbandry practices, mean concentrations of fecal androgen metabolites (fAM), and baseline concentrations of fecal glucocorticoid metabolites (fGM), inbreeding coefficients, and generations each male was removed from the founders in their lineages were not correlated (P > 0.05) with the total number of spermatozoa or the proportion of spermatozoa with normal morphology. Total sperm count was positively correlated (P < 0.05, R2 = 0.86) with the weekly intake of polyunsaturated fatty acids (PUFA) and the proportion of spermatozoa with normal morphology tended (P < 0.10, R2 = 0.31) to be positively correlated with copper intake. Altering the nutrient composition of snow leopard diets could provide managers with a possible method of improving reproductive traits in this endangered species. LAY SUMMARY: The population of snow leopards (Uncia uncia) maintained in US zoos has been declining since 1993 due to poor breeding success. Our objective was to assess the reproductive traits of male snow leopards and identify factors (e.g. hormones, diet, genetics) that may be affecting the quality of semen produced and therefore subsequent fertility. Within a cohort of 32 male snow leopards maintained at 27 US zoos, we found that 34% produced less than 5 million sperm and 27% of males produced sperm where less than 20% looked normal. The quantity and quality of the recovered sperm was not correlated with husbandry practices, concentrations of hormones (androgens and glucocorticoids) in feces, or genetics. However, the number of sperm was positively correlated with polyunsaturated fatty acids in the diet. Altering the nutrient composition of snow leopard diets could provide managers with a possible method of improving reproductive traits in this endangered species.

Nutrient evaluation of a pork by-product and its use as environmental enrichment for managed large exotic cats.

North American zoological institutions typically feed ground raw meat diets to large exotic cats. These diets typically are nutritionally complete, but lack physical properties characteristic of whole prey. Lack of mastication and prey manipulation may contribute to behavioral and health challenges. Pork by-products may provide environmental enrichment to mitigate these challenges. The objectives of this study were to evaluate a pig head for nutritional composition and to determine if a pig head was biologically relevant environmental enrichment for managed large exotic cats. Pig heads consisted of: DM: 48.5%; OM: 60.7%; CP: 38.4%; fat: 22.0%; CF: 13.5%; TDF: 3.4%; GE: 4.1 kcal/g DM. Five individually housed exotic cats (Panthera tigris tigris, Panthera tigris altaica (n = 2), Panthera tigris jacksoni, Panthera leo) were observed in 2-h blocks, 24-h before pig head introduction (Baseline), at time of pig head introduction (Enrichment) and immediately after the pig head was removed (Post Enrichment) via instantaneous scan sampling for 4 consecutive weeks. Active behaviors were 55.7% higher on Enrichment compared to Baseline days, and 26.4% higher compared to Post Enrichment days (p<0.0001). Active behaviors were 39.8% higher on Post Enrichment compared to Baseline days (p<0.0001). Total active behaviors were highest (p<0.0001) in week 3 and lowest (p<0.0001) in week 4 with differences as high as 64.5% seen among weeks. In conclusion, pig heads have potential to provide nutrient dense enrichment to large exotic cats, and employing a pig head as environmental enrichment increased active behaviors and did not lose novelty.

ESTIMATED COMPOSITION OF DIETS FED TO CAPTIVE BLACK-AND-WHITE RUFFED LEMURS (VARECIA VARIEGATA) AT 33 U.S. ZOOLOGICAL INSTITUTIONS.

Data on captive diets for black-and-white ruffed lemurs (Varecia variegata) are limited. Information on food items used, inclusion amounts, and the chemical composition of diets is needed to improve the management of nutrition-related health problems seen in captive lemurs (e.g., obesity) that have not been reported in their wild counterparts. To determine the ingredient and nutrient composition of diets for captive V. variegata, U.S. zoological institutions were surveyed. Chemical composition of reported diets was estimated using Nutritionist Pro™ (Axxya Systems, Stafford, Texas 77477, USA), and these values were compared numerically to wild lemur diets from the literature. Institutions included from six to greater than 30 different ingredients in their diets, including fruits (0.0-84.1%), vegetables (7.5-70.0%), greens (1.0-28.5%), and commercially available feeds (1.5-68.6%). Nutrient concentrations of captive diets ranged as follows: dry matter (DM), 14.5-67.6%; organic matter, 93.1-97.2% DM basis (DMB); crude protein, 7.9-23.9% DMB; fat, 2.0-6.5% DMB; total dietary fiber, 10.1-28.1% DMB; and N-free extract, 38.9-74.4% DMB. Captive diets had lower fat and total dietary fiber and higher protein and N-free extract compared to wild fruit items from Madagascar. Reducing the amount of fruit in captive diets for V. variegata would be expected to decrease digestible carbohydrate content and increase fiber content of these diets, which has implications for the prevalence of obesity in captive animals.

Apparent total tract macronutrient and energy digestibility of 1- to- 3-day-old whole chicks, adult ground chicken, and extruded and canned chicken-based diets in African wildcats (Felis silvestris lybica).

Our objectives were to evaluate the composition of whole 1- to- 3-day-old chicks (Whole), ground adult chicken (Ground), chicken-based canned diet (Canned), and chicken-based extruded diet (Extruded); and evaluate apparent total tract energy and macronutrient digestibility of these diets by four captive African wildcats (Felis silvestrus lybica) utilizing a Latin Square design. We analyzed diets for macronutrient and mineral (Ca, P, K, Na, Mg, Fe, Cu, Mn, Zn, and S) composition, and screened for potentially pathogenic bacteria. Canned and Extruded diets tested negative for all microbes and met macronutrient and mineral recommendations for domestic cat foods [AAFCO (2012). Official publication. Oxford, IN: AAFCO]. Whole prey diets (Ground and Whole) met macronutrient requirements for domestic cats; however, they were below recommendations in some minerals [Mn, Cu, K, and Na; AAFCO (2012). Official publication. Oxford, IN: AAFCO], and tested positive for potentially pathogenic microorganisms (Salmonella, E. coli spp.). For all diets, apparent total tract organic matter digestibility was high (>85%). Organic matter digestibility was higher (P ≤ 0.05) for cats fed Ground (94%) compared to those fed Canned, Extruded, or Whole (87, 86, and 85%, respectively). Apparent total tract crude protein digestibility was lower than expected (i.e., <85%) for cats fed Extruded (81%) and fat digestibility was lower than expected (i.e., <90%) for cats fed Whole (82%). Cats fed whole prey items tested herein adequately maintained BW short-term; however, long-term studies are needed. These data indicate that there may be a need to monitor whole prey composition and when necessary, adjust the diet to account for potential deficiencies.

Nitrogen metabolism of four raw meat diets in domestic cats.

Little nutritional information has been collected from domestic cats fed raw meat diets. The objective of the present study was to evaluate differences in N metabolism of domestic cats fed raw beef-based diet (66 % crude protein (CP) and 20 % fat), bison-based diet (49 % CP and 39 % fat), elk-based diet (79 % CP and 6 % fat) and horse-based diet (60 % CP and 26 % fat). A total of eight intact adult female cats were fed to maintain body weight in a cross-over design. Daily food intake, faecal and urinary outputs, and N metabolism were measured. Dietary N was highly digestible (96.8 (SEM 0.7)) for all treatments. Urinary N accounted for a majority of total N excretion, and differences in total N excretion reflect differences in urinary N. Differences in N intake and N absorption were due to differences in CP levels among diets. N retention was similar to values reported in the literature for domestic cats fed purified and traditional extruded diets. Despite differences in protein concentrations and N intake, all raw meats tested maintained N metabolism.