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

Chronic Stress-Related Gastroenteric Pathology in Cheetah: Relation between Intrinsic and Extrinsic Factors

Simple Summary

The cheetah is the fastest land mammal. Habitat destruction, high mortality due to other predators, and illegal wildlife trade has led to a decrease in the wild population. Currently, the global adult population present in their natural habitat is estimated to be 7100 individuals. In captivity, the population suffers from limited reproduction and disease. Both the wild and captive populations have reduced genetic diversity from a historic bottleneck, leading to increased ecological and environmental vulnerability. Over the years, conservation programs have been developed for habitat protection, management of human–animal conflict, and the study of disease and genetics. Among these, the one with the greatest prevalence in captivity is chronic gastritis. This review analyzes the scientific literature on gastric pathology in cheetah, with the potential causes divided into “extrinsic factors”, such as living conditions and diet, and “intrinsic factors”, including the presence of Helicobacter-like organisms and the genetic predisposition.

Abstract

The rapid decline of cheetah (Acinonyx jubatus) throughout their range and long-term studies of captive breeding has increased conservation action for this species including the study of chronic diseases. Gastritis is one of the captive diseases that leads to high mortality presented with symptoms including vomiting, diarrhea, anorexia, and weight loss. The disease presents different histological lesions in the gastrointestinal tract that are characterized by inconstant and different clinical appearance in captive and free-range cheetahs. The aim of this review is to summarize the causes of chronic gastritis in the cheetah. Factors including diet, living conditions, infections with gastric Helicobacter-like organisms (GHLOs), the lack of genetic polymorphism and the cheetah’s specific-immunocompetence are analyzed. All studies on gastroenteric cheetah pathologies, conducted between 1991 (to the best of our knowledge, the first report on online databases) and 2021, are included in this review, highlighting the possible correlation between stress-related captive conditions and chronic gastric pathology.

Effects of Dietary Macronutrient Profile on Apparent Total Tract Macronutrient Digestibility and Fecal Microbiota, Fermentative Metabolites, and Bile Acids of Female Dogs after Spay Surgery

Obesity and estrogen reduction are known to impact the gut microbiota and gut microbial-derived metabolites in some species, but limited information is available in dogs. The aim of this study was to determine the effects of dietary macronutrient profile on apparent total tract macronutrient digestibility, fecal microbiota, and fecal metabolites of adult female dogs after spay surgery. Twenty-eight adult intact female beagles (age: 3.02 ± 0.71 yr, BW: 10.28 ± 0.77 kg; BCS: 4.98 ± 0.57) were used. After a 5-wk baseline phase (wk 0), 24 dogs were spayed and randomly allotted to one of three experimental diets (n=8/group): 1) control (CO) containing moderate protein and fiber (COSP), 2) high-protein, high-fiber (HPHF), or 3) high-protein, high-fiber plus omega-3 and medium-chain fatty acids (HPHFO). Four dogs were sham-operated and fed CO (COSH). All dogs were fed to maintain BW for 12 wk after spay, then allowed to consume twice that amount for 12 wk. Fecal samples were collected at wk 0, 12, and 24 for digestibility, microbiota, and metabolite analysis. All data were analyzed using repeated measures and linear Mixed Models procedure of SAS 9.4, with results reported as change from baseline. Apparent organic matter and energy digestibilities had greater decreases in HPHF and HPHFO than COSH and COSP. Increases in fecal acetate, total short-chain fatty acids, and secondary bile acids were greater and decreases in primary bile acids were greater in HPHF and HPHFO. Principal coordinates analysis of weighted UniFrac distances revealed that HPHF and HPHFO clustered together and separately from COSH and COSP at wk 12 and 24, with relative abundances of Faecalibacterium, Romboutsia, and Fusobacterium increasing to a greater extent and Catenibacterium, Bifidobacterium, Prevotella 9, Eubacterium, and Megamonas decreasing to a greater extent in HPHF or HPHFO. Our results suggest that high-protein, high-fiber diets alter nutrient and energy digestibilities, fecal metabolite concentrations, and fecal gut microbiota, but spay surgery had minor effects. Future research is needed to investigate how food intake, nutrient profile, and changes in hormone production influence gut microbiota and metabolites of dogs individually and how this knowledge may be used to manage spayed pets.

Plant-eating carnivores: Multispecies analysis on factors influencing the frequency of plant occurrence in obligate carnivores

Plant-eating behavior is one of the greatest mysteries in obligate carnivores. Despite unsuitable morphological and physiological traits for plant consumption, the presence of plants in scat or stomach contents has been reported in various carnivorous species. However, researchers' interpretations of this subject are varied, and knowledge about it is scarce, without any multispecies studies. This study assessed the extent of variation in the frequency of plant occurrence in scat and stomach contents, as well as its relationship with various factors in 24 felid species using data from 213 published articles. Since the frequency of plant occurrence has not always been reported, we created two-part models and estimated parameters in a Bayesian framework. We found a significant negative relationship between the frequency of plant occurrence and body mass. This may be because plant-eating behavior reduces the energy loss caused by parasites and increases the efficiency of energy intake, which has a greater importance in smaller animals that have relatively high metabolic rates. This exploratory study highlights the importance of considering plant consumption in dietary studies on carnivorous species to understand the adaptive significance of this behavior and the relationship between obligate carnivores and plants.

Feeding practices and other factors associated with faecal consistency and the frequencies of vomiting and diarrhoea in captive tigers (Panthera tigris)

Gastrointestinal (GI) health is important to the welfare of captive tigers, and diet is considered a likely influencing factor. A survey was performed to collect information on GI health indicators and diet of tigers housed in zoological facilities across the globe. Completed surveys were received for one tiger from each of 32 facilities. Three (9%) tigers were reported as being diagnosed as having current GI disease; 24 (75%) had ideal (soft with shape) faeces ‘often’ to ‘always’ during the four weeks before survey completion. Potential associations between current GI disease and other variables could not be explored because of the low disease prevalence. Commercial raw meat diets were the most commonly fed diet type, and the most common food source was horse. Upon multivariate analysis, including country as a covariate, the odds and frequency of vomiting during the previous six months increased with the frequency of feeding muscle meat and chicken, and decreased as the frequency of feeding long bones increased. The odds and frequency of diarrhoea over the previous six months increased with the frequency of feeding beef and muscle meat; and the frequency of liquid faeces in the previous four weeks increased with oral antimicrobial treatment and increasing frequency of feeding beef. Although limited by the small sample size, these findings characterised the nutritional care that captive tigers currently receive and provided preliminary insight into dietary associations with indicators of GI health. The findings support the need to consider species-specific dietary adaptations and for further investigations into the health impact of diet in captive tigers.

Does faecal matter reflect location? An initial assessment of isotopic variability between consumed prey remains and faecal matter for wild jaguars. ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2019;55:478-498. [PMID: 31402710 DOI: 10.1080/10256016.2019.1648263]

Faecal isotopic analysis may complement other non-invasive wildlife survey tools for monitoring landscape use by carnivores, such as motion-detecting cameras and non-invasive genetic sampling. We analysed carbon, nitrogen, and strontium isotopes in faecal matter produced by jaguars (Panthera onca) as well as bones from consumed prey at the Mountain Pine Ridge Forest Reserve (MPR) in Belize, Central America. The MPR is ideally suited for a spatial isotope study as vegetation and geology both vary considerably. The isotopic composition of faecal matter should reflect the habitat and geology where consumed prey lived. We used bone from consumed prey recovered from jaguar scats as a proxy for diet. Faecal matter and bone showed comparable spatial isotopic trends, suggesting that the isotopic composition of jaguar faeces can be used to detect foraging in different habitats (pine forest versus broadleaf forest) or on different geologies (Mesozoic carbonates; Palaeozoic granite, contact metamorphics, and metasediments). This result is reassuring as bones are not always present in carnivore scats. Studying landscape use by cryptic and wide-ranging carnivore species like jaguars remains challenging. Isotopic analysis of faecal matter complements the existing array of non-invasive spatial monitoring tools.

Grain free diets for utility dogs during training work: Evaluation of the nutrient digestibility and faecal characteristics

Two different diets characterized by the absence of cereals or by the presence of conventional cereals were evaluated on the nutrient digestibility and faecal characteristics and faecal fermentative end-product concentrations of 8 neutered adult Labrador retrievers housed at the Regional Centre Helen Keller (Messina, Italy) during the training work for the service guide for the blind. Dogs (age = 17 ± 1 months, initial body weight [BW] = 26.3 ± 1 kg, and body condition score [BCS] = 4.5 ± 0.11) were divided into 2 homogeneous groups for sex (half males and half females). Dogs in the grain free (GF) group were fed a commercial diet characterized by the absence of grain cereals, and dogs in the control (CTR) group were fed a super-premium pet food characterized by conventional grains as the carbohydrate source. The trial lasted 84 d, preceded by a 7-d of adaption period. Physical examination, digestibility, and faecal characteristics were studied. The statistical model included the effects of diet (GF vs. CTR), time (from d 0 to 84, end of the trial) and the interaction (diet × time). The high-protein, low-carbohydrate dry diet (GF) offered higher apparent nutrient digestibility of protein (+10%; P = 0.002) and fat (+7%; P < 0.001) and more stable large intestinal fermentation of carbohydrate compared to the commercial high-carbohydrate dry diet, enabling dogs to use nutrients from the diet more efficiently and thus requiring less food (-13%) to satisfy their nutrient requirements, producing less excrement (-33%; P = 0.033), and reaching a higher final BW (+8%; P < 0.0001) and a higher final BCS (+15%; P = 0.003). Therefore, the GF diet appears the nutritional plan most suitable for these animals taking due account not only of the training work done by animals with their increased nutrient and energy needs, but also of the gastrointestinal disorders consequent to stress coming from work and life in kennels, which cause in the Labrador retrievers an unusual weight loss.

Addition of plant dietary fibre to a raw red meat high protein, high fat diet, alters the faecal bacteriome and organic acid profiles of the domestic cat (Felis catus)

Commercial diets high in animal protein and fat are increasingly being developed for pets, however little is understood about the impacts of feeding such diets to domestic cats. The carbohydrate content of these diets is typically low, and dietary fibre is often not included. Dietary fibre is believed to be important in the feline gastrointestinal tract, promoting stool formation and providing a substrate for the hindgut microbiome. Therefore, we aimed to determine the effects of adding plant-based dietary fibre to a high animal protein and fat diet. Twelve domestic short hair cats were fed three complete and balanced diets in a cross-over design for blocks of 21 days: raw meat (Raw), raw meat plus fibre (2%, ‘as is’ inclusion of inulin and cellulose; Raw+Fibre) and a commercially available Kibble diet. A commercially available canned diet was fed for 21 days as a washout phase. Apparent macronutrient digestibility, faecal output, score, pH, organic acid concentrations and bacteriome profiles were determined. Diet significantly affected all faecal parameters measured. The addition of dietary fibre to the raw meat diet was found to reduce apparent macronutrient digestibility, increase faecal output, pH and score. Thirty one bacterial taxa were significantly affected by diet. Prevotella was found to dominate in the Kibble diet, Clostridium and Fusobacterium in the Raw diet, and Prevotella and a group of unclassified Peptostreptococcaceae in the Raw+Fibre diet. Our results show that diets of different macronutrient proportions can strongly influence the faecal microbiome composition and metabolism, as shown by altered organic acid concentrations and faecal pH, in the domestic cat. The addition of 2% of each fibre to the Raw diet shifted faecal parameters closer to those produced by feeding a Kibble diet. These results provide a basis for further research assessing raw red meat diets to domestic cats.

Beneficial Effect of Intestinal Fermentation of Natural Polysaccharides

With the rapid development of modern society, many chronic diseases are increasing including diabetes, obesity, cardiovascular diseases, etc., which further cause an increased death rate worldwide. A high caloric diet with reduced natural polysaccharides, typically indigestible polysaccharides, is considered a health risk factor. With solid evidence accumulating that indigestible polysaccharides can effectively prevent and/or ameliorate symptoms of many chronic diseases, we give a narrative review of many natural polysaccharides extracted from various food resources which mainly contribute their health beneficial functions via intestinal fermentation.

Are carnivore digestive separation mechanisms revealed on structure-rich diets?: Faecal inconsistency in dogs (Canis familiaris) fed day old chicks

Pronounced variations in faecal consistency have been described anecdotally for some carnivore species fed a structure-rich diet. Typically two faecal consistencies are distinguished, namely hard and firm versus liquid and viscous faeces. It is possible that a separation mechanism is operating in the carnivore digestive tract, as in many herbivore species. Six beagle dogs were fed two experimental diets in a cross-over design of 7 days. Test diets consisted of chunked day old chicks differing only in particle size (fine = 7.8 mm vs coarse = 13 mm) in order to vary dietary structure. Digestive retention time was measured using titanium oxide (TiO2) as marker. The total faecal output was scored for consistency and faecal fermentation profiles were evaluated through faecal short-chain fatty acid (SCFA) and ammonia (NH3) analyses. A total of 181 faecal samples were collected. Dietary particle size did not affect faecal consistency, fermentative end products nor mean retention time (MRT). However, a faecal consistency dichotomy was observed with firm faeces (score 2-2.5) and soft faeces (score 4-4.5) being the most frequently occurring consistencies in an almost alternating pattern in every single dog. Firm and soft faeces differed distinctively in fermentative profiles. Although the structure difference between diets did not affect the faecal dichotomy, feeding whole prey provoked the occurrence of the latter which raises suspicion of a digestive separation mechanism in the canine digestive tract. Further faecal characterisation is however required in order to unravel the underlying mechanism.

Evaluation of raw pork as a commercially manufactured diet option for zoo-managed African wildcats (Felis silvestris lybica)

Second to beef, pork is a major protein source produced in the US. Properly sourced and handled pork could be utilized as a protein option for zoo-managed carnivores. Concerns of high levels of microbial populations in raw meat diets are common. The objectives of this study were to determine apparent total tract macronutrient and energy digestibility and fecal scores from cats fed a commercially manufactured raw pork-based diet compared with commercially available raw carnivore diets formulated with either horse or beef and evaluate typical microbial population variation among the diets. Dietary treatments consisted of 4 raw meat-based diets: Horse, Beef, Pork, and beef/horse Blend. All diets were highly digestible, especially fat digestibility (98.6 to 99.7%) in which there were no statistical differences among diets. Digestibility of organic matter (OM) was greater (P = 0.05) when cats consumed the Blend diet (97.2%) compared to the Pork diet (93.1%). Fecal scores ranged from 1.6 to 2.6 (on a 5-point scale), with Beef (2.6) being greater than (P = 0.01) Horse (1.6) and (P = 0.02) Pork (1.9). E. coli counts ranged from 110 to 10,000 cfu/g; total coliforms: 150 to 28,000 cfu/g; yeast: 20 to 4,000 cfu/g; mold count: not detectable to 10 cfu/g; and aerobic plate count: 23,000 to 26,000,000 cfu/g. Staphylococcus aureus was not detected in any of the diets. Salmonella was presumptive positive in the Pork and Blend diet, and was negative in the other 2 diets. In conclusion, commercially manufactured diets have varying microbial counts. All diets, including the raw pork-based diet were well utilized by exotic small cats and can be included among dietary options for managed felids.

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.

In vitro fermentation characteristics of novel fibers, coconut endosperm fiber and chicory pulp, using canine fecal inoculum

The objective of this experiment was to determine the effects of in vitro fermentation of coconut endosperm fiber (CEF), chicory pulp (CHP), and selective blends of these substrates on SCFA production and changes in microbiota using canine fecal inocula. A total of 6 individual substrates, including short-chain fructooligosaccharide (scFOS; a well-established prebiotic source), pectin (PEC; used as a positive control), pelletized cellulose (PC; used as a negative control), beet pulp (BP; considered the gold standard fiber source in pet foods), CEF, and CHP, and 3 CEF:CHP blends (75:25% CEF:CHP [B1], 50:50% CEF:CHP [B2], and 25:75% CEF:CHP [B3]) were tested. Triplicate samples of each substrate were fermented for 0, 8, and 16 h after inoculation. A significant substrate × time interaction (P < 0.05) was observed for pH change and acetate, propionate, butyrate, and total SCFA concentrations. After 8 and 16 h, pH change was greatest for scFOS (-2.0 and -3.0, respectively) and smallest for PC (0.0 and -0.1, respectively). After 16 h, CEF had a greater butyrate concentration than CHP and all the CEF:CHP blends and it was not different than PEC. The substrate × time interaction was significant for bifidobacteria (P < 0.05) and lactobacilli (P < 0.05). After 8 h, bifidobacteria was greatest for BP and lowest for PC (12.7 and 10.0 log10 cfu/tube, respectively). After 16 h, PC had the lowest and scFOS had the greatest bifidobacteria (6.7 and 13.3 log10 cfu/tube, respectively). In general, CEF, CHP, and their blends had similar bifidobacteria populations after 8 and 16 h of fermentation when compared with BP and scFOS. After 16 h, lactobacilli populations were greatest for B1, B2, B3, BP, and scFOS, intermediate for PEC, and lowest for PC (P < 0.05). Overall, our data suggest that CEF had a butyrogenic effect and that CEF, CHP, and their blends had similar bifidobacteria and lactobacilli populations as popular prebiotic and fiber substrates. Future research should investigate the effects of CEF, CHP, and their blends on gastrointestinal health and fecal quality in dogs.

Commercially available avian and mammalian whole prey diet items targeted for consumption by managed exotic and domestic pet felines: macronutrient, mineral, and long-chain fatty acid composition

Whole prey diets encourage species-typical behaviors making them popular in the zoo and home setting for captive exotic and domestic felids, respectively. We evaluated macronutrient, mineral, and long-chain fatty acid composition of 20 whole prey items: mice (1-2, 10-13, 21-25, 30-40, and 150-180 days of age); rats (1-4, 10-13, 21-25, 33-42, and >60 days of age); rabbits (still born, 30-45 days, >65 days with skin, and >65 days of age with skin removed); chicken (1-3 days of age, ground adult); duck (ground adult); and quail (1-3, 21-40, and >60 days of age). Composition of whole prey was highly variable (15-40% DM, 34-75% CP, 10-60% fat, and 8-18% ash). A majority of whole prey samples (15/20) had at least one mineral or fatty acid below AAFCO [] or NRC [] minimum recommended concentrations for domestic cats (K, Na, Cl, Mg, Cu, Mn, and/or Zn; total fat, linolenic acid, arachidonic acid and/or EPA and DHA). These data identify potential nutrient deficiencies allowing for alterations in dietary formulation prior to long-term feeding.

Alternative dietary fiber sources in companion animal nutrition

The US has a pet population of approximately 70 million dogs and 74 million cats. Humans have developed a strong emotional bond with companion animals. As a consequence, pet owners seek ways to improve health, quality of life and longevity of their pets. Advances in canine and feline nutrition have contributed to improved longevity and well-being. Dietary fibers have gained renewed interest in the pet food industry, due to their important role in affecting laxation and stool quality. More recently, because of increased awareness of the beneficial effects of dietary fibers in health, as well as the popularity of functional foods and holistic and natural diets, alternative and novel carbohydrates have become widespread in human and pet nutrition. Fiber sources from cereal grains, whole grains and fruits have received increasing attention by the pet food industry and pet owners. While limited scientific information is available on the nutritional and nutraceutical properties of alternative fiber sources, studies indicate that corn fiber is an efficacious fiber source for pets, showing no detrimental effects on palatability or nutrient digestibility, while lowering the glycemic response in adult dogs. Fruit fiber and pomaces have good water-binding properties, which may be advantageous in wet pet food production, where a greater water content is required, along with low water activity and a firm texture of the final product. Rice bran is a palatable fiber source for dogs and may be an economical alternative to prebiotic supplementation of pet foods. However, it increases the dietary requirement of taurine in cats. Barley up to 40% in a dry extruded diet is well tolerated by adult dogs. In addition, consumption of complex carbohydrates has shown a protective effect on cardiovascular disease and oxidative stress. Alternative fiber sources are suitable ingredients for pet foods. They have been shown to be nutritionally adequate and to have potential nutraceutical properties.

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.