Cheryl L. Morris

Apparent total tract energy and macronutrient digestibility and fecal fermentative end-product concentrations of domestic cats fed extruded, raw beef-based, and cooked beef-based diets

The objectives of this study were to determine differences in apparent total tract energy and macronutrient digestibility, fecal and urine characteristics, and serum chemistry of domestic cats fed raw and cooked meat-based diets and extruded diet. Nine adult female domestic shorthair cats were utilized in a replicated 3 × 3 Latin square design. Dietary treatments included a high-protein extruded diet (EX; 57% CP), a raw beef-based diet (RB; 53% CP), and a cooked beef-based diet (CB; 52% CP). Cats were housed individually in metabolic cages and fed to maintain BW. The study consisted of three 21-d periods. Each period included diet adaptation during d 0 to 16; fecal and urine sample collections during d 17 to 20; and blood sample collection at d 21. Food intake was measured daily. Total feces and urine were collected for determination of nutrient digestibility. In addition, a fresh urine sample was collected from each cat for urinalysis, and a fresh fecal sample was collected from each cat for determination of DM percentage and ammonia, short-chain fatty acid (SCFA), and branched-chain fatty acid (BCFA) concentrations. All feces were scored after collection using a scale ranging from 1 (hard, dry pellets) to 5 (watery, liquid that can be poured). Blood was analyzed for serum metabolites. Apparent total tract DM, OM, CP, fat, and GE digestibilities were greater (P ≤ 0.05) in cats fed RB and CB than those fed EX. Total fecal SCFA concentrations did not differ among dietary treatments; however, molar ratios of SCFA were modified by diet, with cats fed RB and CB having an increased (P ≤ 0.05) proportion of fecal propionate and decreased (P ≤ 0.05) proportion of fecal butyrate compared with cats fed EX. Fecal concentrations of ammonia, isobutyrate, valerate, isovalerate, and total BCFA were greater (P ≤ 0.05) in cats fed EX compared with cats fed RB and CB. Our results indicated that cooking a raw meat diet does not alter apparent total tract energy and macronutrient digestibility and may also minimize risk of microbial contamination. Given the increasing popularity of feeding raw diets and the metabolic differences noted in this experiment, further research focused on the adequacy and safety of raw beef-based diets in domestic cats is justified.

Evaluation of four raw meat diets using domestic cats, captive exotic felids, and cecectomized roosters

Our objective was to evaluate raw meat diets for captive exotic and domestic carnivores containing traditional and alternative raw meat sources, specifically, beef trimmings, bison trimmings, elk muscle meat, and horse trimmings. We aimed to examine diet composition and protein quality; apparent total tract energy and macronutrient digestibility in domestic cats, African wildcats, jaguars, and Malayan tigers; and ME and fecal fermentative end-products in domestic cats. Because of variation in the meat sources, dietary proximate, AA, and long-chain fatty acid composition were variable. Our analyses indicated that all diets had essential fatty acid deficiencies, and the elk diet (i.e., trimmed muscle meat) was deficient in total fat. Standardized AA digestibilities measured using the cecectomized rooster assay were high (>87%). Using the NRC minimum requirements for the growth of kittens, the first limiting AA of all diets was the combined requirement of Met and Cys (AA score: 81 to 95; protein digestibility corrected AA score: 75 to 90). All diets were highly digestible (88 to 89% OM digestibility). There was no effect of diet or felid species on DM (85 to 87%), OM, and GE (90 to 91%) digestibilities. Apparent CP digestibility was greater (P≤0.05) in cats fed elk (97%) compared with those fed bison (96%), and greater (P≤0.05) in wildcats (97%) and domestic cats (97%) compared with tigers (95%). The diet and species interaction (P≤0.05) was observed for apparent fat digestibility. In domestic cats, the fresh fecal pH and proportions of acetate and butyrate were altered (P≤0.05) due to diet. Diet also affected (P≤0.05) fresh fecal concentrations of total branched-chain fatty acids, valerate, and Lactobacillus genus. In conclusion, although the raw meat diets were highly digestible, because of variation in raw meat sources the nutrient composition of the diets was variable. Thus, compositional analysis of raw meat sources is necessary for proper diet formulation. The types of meat commonly used in raw meat diets may be deficient in total fat (trimmed muscle meat) and essential fatty acids (trimmings and muscle meats). Additionally, differences in raw meat source nutrient composition and digestibility affect the beneficial and putrefactive fermentative end-products found in feces.

Influence of dietary fiber type and amount on energy and nutrient digestibility, fecal characteristics, and fecal fermentative end-product concentrations in captive exotic felids fed a raw beef-based diet

Little nutritional or metabolic information has been collected from captive exotic cats fed raw diets. In particular, fiber types and concentrations for use in raw meat-based diets for captive exotic felids have not been well studied. Our objective was to evaluate the effects of fiber type and concentration on apparent total tract energy and macronutrient digestibility, fecal characteristics, and fecal fermentative end-products in captive exotic felids. Four animals of each captive exotic species (jaguar (Panthera onca), cheetah (Acinonyz jubatus), Malayan tiger (Panthera tigris corbetti), and Siberian tiger (Panthera tigris altaica) were randomized in four 4 × 4 Latin square designs (1 Latin square per species) to 1 of the 4 raw beef-based dietary treatments (94.7 to 96.7% beef trimmings): 2 or 4% cellulose or 2 or 4% beet pulp. Felid species, fiber type, and fiber concentration all impacted digestibility and fecal fermentative end-products. Inclusion of beet pulp increased (P ≤ 0.05) fecal short-chain fatty acids and fecal output in all cats. Inclusion of 2 and 4% cellulose, and 4% beet pulp increased (P ≤ 0.05) fecal bulk and diluted fecal branched-chain fatty acid concentrations compared with 2% beet pulp. Apparent total tract DM, OM, fat, and GE digestibility coefficients decreased (P ≤ 0.05) linearly with BW of cats. Additionally, fecal moisture, fecal score, and concentrations of fermentative end-products increased (P ≤ 0.05) with BW. Although the response of many outcomes was dependent on cat size, in general, beet pulp increased wet fecal weight, fecal scores, and fecal metabolites, and reduced fecal pH. Cellulose generally reduced DM and OM digestibility, but increased dry fecal weight and fecal percent DM. Although beet pulp and cellulose fibers were tested individually in this study, these data indicate that the optimum fiber type and concentration for inclusion in captive exotic felid diets is likely a combination of fermentable and nonfermentable fibers, with the optimal fiber blend being dependent on species. Smaller cats, such as cheetahs and jaguars, tolerated fermentable fibers, whereas larger cats, such as Malayan and Siberian tigers, appeared to require more insoluble fibers that limit fermentation and provide fecal bulk. Further research is required to test whether these trends hold true when fed in combination.

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.

Apparent total tract energy and macronutrient digestibility of one- to three-day-old, adult ground, extruded, and canned chicken-based diets in domestic cats (Felis silvestris catus)

There has been a recent increase in the popularity of feeding unconventional diets, including whole prey diets, to domestic cats (Felis silvestris catus). Data are needed that allow animal caretakers to choose and formulate diets that meet the nutritional requirements of their cats. Our objective was to evaluate the effects of feeding 1- to 3-d-old whole chicks (WHO), ground adult chicken product (GRO), a chicken-based canned diet (CAN), and a chicken-based extruded diet (EXT) on apparent total tract energy and macronutrient digestibility, N balance, and blood metabolites of domestic cats (n = 11). Macronutrient, energy, and moisture concentrations of diets varied greatly (e.g., CP: 35 to 72% DM); however, cats fed all diets maintained BW and N balance. In general, cats fed WHO had lower nutrient digestibility than those fed CAN and EXT. Cats fed GRO had greater nutrient digestibility than cats fed commercial diets. For example, apparent OM and GE digestibility coefficients were greater (P ≤ 0.05) for cats fed CAN (86 and 88%, respectively), EXT (88 and 88%), and GRO (94 and 95%) compared with those fed WHO (83 and 83%) and greater (P ≤ 0.05) for cats fed GRO compared with those fed CAN and EXT. Many blood metabolites were modified by diet, but most remained within reference ranges for domestic cats. Serum cholesterol was elevated above the reference range for all treatments and greater (P ≤ 0.05) for cats fed WHO compared with those fed CAN, EXT, and GRO. Serum creatinine concentrations were above the reference range for all treatments and greater (P ≤ 0.05) for cats fed GRO compared with those fed CAN or WHO. These data indicate that the whole prey tested herein maintained short-term health and are adequately digestible for use in companion animal diets. Research is needed to determine the global and long-term health implications of feeding whole or ground diets to domestic cats, which may be different in terms of macronutrient, energy, and moisture profiles and nutrient digestibility.

Influence of pork and pork by-products on macronutrient and energy digestibility and palatability in large exotic felids

Two experiments were conducted to evaluate digestibility and palatability of a new commercial pork-based raw diet for zoo-managed felids. Currently 2 protein sources (beef or horse) comprise the majority of commercial raw meat diet formulations for exotic carnivores in zoological institutions. Pork-based diets have traditionally not been widely utilized and thus nutrient digestibility of pork has not been adequately evaluated in exotic carnivores. The objectives of this study were 1) to determine if a pork-based diet had similar apparent total tract macronutrient digestibility and fecal scores as standard zoo carnivore diets formulated with either horse or beef, in large exotic felids and 2) evaluate palatability of pork for use in zoos. Ten exotic felids were used including cheetahs (; 3), jaguars (; = 3), leopards (; 2), puma (; 1), and Bengal tiger (; 1). Dietary treatments consisted of 4 raw meat diets: 1 horse-based (Horse), 2 beef-based (B1, B2), and 1 pork-based diet (Pork). Fecal scores also were evaluated (1 = hard to 5 = watery/liquid). This randomized crossover design study consisted of 4 periods, each 10 d for treatment adaptation followed by 4 d of sample collection. Dry matter and crude protein apparent digestibility values were greater ( < 0.05) in felids fed Pork (88.0 and 95.7%) compared with felids fed Horse (83.6 and 92.7%) and B2 (85.6 and 93.1%). Apparent organic matter digestibility was greater ( < 0.05) in felids fed Pork (90.8%) than felids fed Horse (88.5%). Apparent fat digestibility values were high across all treatments but were greater ( < 0.05) in felids fed Pork (98.5%) compared with felids fed B1 (95.5%) or B2 (96.5%). Gross energy digestibility values were greater in felids fed Pork (92.4%) compared with B1 (90.2%). Average fecal scores were 2.30, 2.94, 3.42, and 3.54 for Horse, Pork, B1 and B2, respectively; and were different ( < 0.05) between treatments with exception of B1 and B2 that did not differ. Felids approached the pork diet first in 65.6% of observations and tasted the pork diet first in 71.9% of observations, compared with a beef-based raw diet. Based on results, the evaluated pork-based diet had similar apparent total tract macronutrient digestibility and palatability compared with standard zoo carnivore formulations. In conclusion, pork-based diets could be included among dietary options for large zoo felids.

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

Abstract 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.

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.