Abstract: Fish proteins have been reported to be more satiating than meat proteins. The objective was to determine the effect of different animal protein pre-meals on satiety. A total of ten intact female hounds were fed pork loin, beef loin, chicken breast, salmon fillet or pollock fillet. Each pre-meal was fed to contain 100 g protein. Blood was collected at 0, 5, 15, 30, 60, 90 and 120 min postprandially and analysed for glucose, insulin, total ghrelin, active glucagon-like peptide-1 (GLP-1) and plasma amino acids (AA). Dogs were fed 2 × metabolisable energy, 3 h following the pre-meal, and intake was determined 30, 60, 180 and 1440 min after food presentation. Glucose decreased over time (P < 0·001), but was lowest (P = 0·01) when dogs consumed pollock or chicken. Insulin increased (P < 0·0001) over time, and was greater (P = 0·09) when dogs consumed salmon. GLP-1 increased (P < 0·001) over time, and was greatest (P = 0·04) when dogs consumed beef. Ghrelin decreased (P < 0·0001) over time for all pre-meals. The tryptophan:large neutral AA ratio tended to be greater (P = 0·08) when dogs consumed pork, salmon and pollock. Different protein sources may influence blood markers in dogs, but it does not appear that fish substrates have different satiating abilities than mammalian or avian sources.
Abstract: Short-chain fructooligosaccharides (scFOS) and galactooligosaccharides (GOS) are nondigestible oligosaccharides that result in a prebiotic effect in some animal species; however, the cat has not been well studied in this regard. This experiment evaluated scFOS and GOS supplementation on nutrient digestibility, fermentative end product production, and fecal microbial ecology of cats. Eight healthy adult cats were fed diets containing no prebiotic, 0.5% scFOS, 0.5% GOS, or 0.5% scFOS + 0.5% GOS (scFOS + GOS) in a replicated 4 × 4 Latin square design. Apparent total tract CP digestibility was decreased (P < 0.05) when cats were fed a diet containing scFOS + GOS compared with the other treatments. Dry matter, OM, acid hydrolyzed fat, and GE digestibilities were not different (P > 0.05) among treatments. Cats fed scFOS-, GOS-, and scFOS + GOS-supplemented diets had greater (P < 0.05) fecal Bifidobacterium spp. populations compared with cats fed the control diet. Fecal pH was less (P < 0.05) for cats fed the scFOS + GOS-supplemented diet compared with the control. Butyrate (P = 0.05) and valerate (P < 0.05) concentrations were greater when cats consumed the scFOS + GOS diet. Acetate tended (P = 0.10) to be greater when cats were fed the scFOS + GOS diet. Total short-chain fatty acid (P = 0.06) and total branched-chain fatty acid (P = 0.06) concentrations also tended to be greater when cats consumed the scFOS + GOS treatment. Fecal protein catabolites, including ammonia, 4-methylphenol, indole, and biogenic amines, blood lymphocytes, neutrophils, total white blood cell counts, or fecal DM concentration and output did not differ (P > 0.05) among treatments. Low level supplementation of scFOS, GOS, and their combination exert positive effects on select indices of gut health in cats.
Abstract: Nine young adult (1.73 ± 0.03 yr) male cats were used to determine the effects of microbial adaptation to select dietary fiber sources on changes in pH in vitro and on total and hydrogen gas, short-chain fatty acid (SCFA), and branched-chain fatty acid (BCFA) production. Cats were adapted to diets containing 4% cellulose, fructooligosaccharides (FOS), or pectin for 30 d before fecal sampling. Each cat was used as a single donor, and fecal inoculum was reacted with each of the aforementioned fiber substrates. Adaptation to dietary FOS resulted in a greater change in pH when exposed to FOS than pectin (adaptation × substrate, P < 0.001). When exposed to the FOS substrate, adaptation to dietary FOS or pectin increased hydrogen gas production (adaptation × substrate, P = 0.021). Adaptation to dietary FOS increased acetate and total SCFA production when exposed to FOS substrate in vitro (adaptation × substrate, P = 0.001). When exposed to the FOS substrate, propionate production tended to increase with adaptation to dietary cellulose (adaptation × substrate, P = 0.060). The BCFA + valerate tended to decrease with adaptation to dietary FOS when exposed to FOS substrate in vitro (adaptation × substrate, P = 0.092). Fructooligosaccharides resulted in the greatest change in pH and production of total gas (P < 0.001), hydrogen gas (P < 0.001), acetate (P < 0.001), propionate (P < 0.001), butyrate (P < 0.001), total SCFA (P < 0.001), and total BCFA + valerate production (P < 0.001). Adaptation to the FOS or pectin diet increased production of hydrogen gas with FOS and pectin substrates. Adaptation to pectin increased (P = 0.033) total gas production with FOS and pectin substrates. Overall, adaptation to either FOS or pectin led to greater SCFA and gas production, but adaptation to FOS resulted in the greatest effect overall.
Abstract: This study is the first to use a metagenomics approach to characterize the phylogeny and functional capacity of the canine gastrointestinal microbiome. Six healthy adult dogs were used in a crossover design and fed a low-fiber control diet (K9C) or one containing 7.5% beet pulp (K9BP). Pooled fecal DNA samples from each treatment were subjected to 454 pyrosequencing, generating 503,280 (K9C) and 505,061 (K9BP) sequences. Dominant bacterial phyla included the Bacteroidetes/Chlorobi group and Firmicutes, both of which comprised ∼35% of all sequences, followed by Proteobacteria (13-15%) and Fusobacteria (7-8%). K9C had a greater percentage of Bacteroidetes, Fusobacteria and Proteobacteria, whereas K9BP had greater proportions of the Bacteroidetes/Chlorobi group and Firmicutes. Archaea were not altered by diet and represented ∼1% of all sequences. All archaea were members of Crenarchaeota and Euryarchaeota, with methanogens being the most abundant and diverse. Three fungi phylotypes were present in K9C, but none in K9BP. Less than 0.4% of sequences were of viral origin, with >99% of them associated with bacteriophages. Primary functional categories were not significantly affected by diet and were associated with carbohydrates; protein metabolism; DNA metabolism; cofactors, vitamins, prosthetic groups and pigments; amino acids and derivatives; cell wall and capsule; and virulence. Hierarchical clustering of several gastrointestinal metagenomes demonstrated phylogenetic and metabolic similarity between dogs, humans and mice. More research is required to provide deeper coverage of the canine microbiome, evaluate effects of age, genetics or environment on its composition and activity, and identify its role in gastrointestinal disease.
Abstract: 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 x 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 as compared to cats fed EX. Fecal concentrations of ammonia, isobutyrate, valerate, isovalerate, and total BCFA were greater (P ≤ 0.05) in cats fed EX compared to 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.
Abstract: During the development of obesity, adipose tissue undergoes major expansion and remodeling, but the biological processes involved in this transition are not well understood. The objective of this study was to analyze global gene expression profiles of adipose tissue in dogs, fed a high-fat diet, during the transition from a lean to obese phenotype. Nine female beagles (4.09 ± 0.64 yr; 8.48 ± 0.35 kg) were randomized to ad libitum feeding or body weight maintenance. Subcutaneous adipose tissue biopsy, blood, and dual x-ray absorptiometry measurements were collected at 0, 4, 8, 12, and 24 wk of feeding. Serum was analyzed for glucose, insulin, fructosamine, triglycerides, free fatty acids, adiponectin, and leptin. Formalin-fixed adipose tissue was used for determination of adipocyte size. Adipose RNA samples were hybridized to Affymetrix Canine 2.0 microarrays. Statistical analysis, using repeated-measures ANOVA, showed ad libitum feeding increased (P < 0.05) body weight (0 wk, 8.36 ± 0.34 kg; 24 wk, 14.64 ± 0.34 kg), body fat mass (0 wk, 1.36 ± 0.24 kg; 24 wk, 6.52 ± 0.24 kg), adipocyte size (0 wk, 114.66 ± 17.38 μm(2); 24 wk, 320.97 ± 0.18.17 μm(2)), and leptin (0 wk, 0.8 ± 1.0 ng/ml; 24 wk, 12.9 ± 1.0 ng/ml). Microarrays displayed 1,665 differentially expressed genes in adipose tissue as weight increased. Alterations were seen in adipose tissue homeostatic processes including metabolism, oxidative stress, mitochondrial homeostasis, and extracellular matrix. Adipose transcriptome changes highlight the dynamic and adaptive response to ad libitum feeding and obesity development.
Abstract: Dogs suffer from many of the same maladies as humans that may be affected by the gut microbiome, but knowledge of the canine microbiome is incomplete. This work aimed to use 16S rDNA tag pyrosequencing to phylogenetically characterize hindgut microbiome in dogs and determine how consumption of dietary fiber affects community structure.
Abstract: Identifying dietary effects on appetite-regulating hormones will enhance our understanding of appetite control. Before complex diets are tested, effects of specific macronutrients or feeding frequency should be identified. The objectives of this nutrition study were to identify differences in endocrine response with feeding frequency (Exp. 1) and after a single dose of a sole macronutrient (Exp. 2). A control diet supplying similar energy content from carbohydrate, protein, and fat was fed to maintain ideal BW. In Exp. 1, 8 healthy adult (1.9 ± 0.1 yr old) female hound cross dogs with an average BW of 22 kg (4.8 ± 0.8 BCS based on a 9-point scale) were randomly allotted to 1 of 2 treatments (fed once or twice daily) in a crossover design. After a 14-d adaptation period, a blood sample was taken (10 mL) before feeding, and samples were collected every 2 h postprandially for 24 h. In Exp. 2, dogs were randomly allotted to 1 of 4 treatments in a 4 × 4 Latin square design. After a 6-d adaptation period, the normal meal on d 7 was replaced with a bolus of maltodextrin (50 g in water; CARB), canned chicken (50 g; PROT), lard (25 g; fat), or water (200 mL). A blood sample (10 mL) was taken at 0, 30, 60, 90, 120, 150, 180, 240, 300, and 360 min postprandial. Total ghrelin, active glucagon-like peptide-1 (GLP-1), insulin, and glucose concentrations were measured. Data were analyzed to compare changes from baseline and area under the curve (AUC) among treatments. In Exp. 1, all hormones were quite variable throughout the day, with a few insulin and GLP-1 differences because of feeding frequency. In Exp. 2, CARB produced a marked peak in glucose and insulin concentrations compared with PROT, fat, or water, resulting in increased glucose (P < 0.001) and insulin (P = 0.07) incremental AUC values. On the other hand, the fat treatment led to increased GLP-1 concentrations over time. Ghrelin AUC was not different among treatments. The circulating hormone data were highly variable and indicate that diet plays a role in insulin and GLP-1 secretion, but more research is required to elucidate these effects.
Abstract: The objective of this study was to determine the effects of feeding commercially available beef- and horse-based diets on nutrient digestibility and fecal characteristics of large captive exotic felids and domestic cats. Four species of large exotic felids including cheetahs, Malayan tigers, jaguars, and Amur tigers, and domestic cats were utilized in a crossover design. Raw meat diets included a beef-based diet (57% protein; 28% fat) and a horse-based diet (51% protein; 30% fat). All cats were acclimated to the diet for 16 days followed by a 4 day collection period, where total feces, including one fresh sample, were collected. All feces were scored on collection. Intake did not differ due to diet, but fecal output was greater when cats consumed the horse-based diet. Total tract apparent dry matter (DM) digestibility was higher (P<0.05) and organic matter (OM) and crude protein (CP) digestibilities were lower (P<0.05) when cats were fed the beef-based diet compared with the horse-based diet. CP digestibility was similar in domestic cats and cheetahs, and greater (P<0.05) than Amur tigers. Fecal scores were lower and fecal DM was greater (P<0.05) when cats consumed the horse-based diet compared with the beef-based diet. Domestic cats had lower (P<0.05) fecal ammonia concentrations compared with all other species. Fecal ammonia concentrations were lowest (P<0.05) when cats were fed the horse-based diet. Fecal total short-chain fatty acid (SCFA), branched-chain fatty acid (BCFA), and butyrate concentrations were higher (P<0.05) when cats consumed the beef-based diet. Our results suggest that the domestic cat serves as an appropriate model for large exotic felid species, but differences among the species exist. Decreased nutrient digestibility by tigers and jaguars should be considered when developing feeding recommendations for these species based on domestic cat data.
Abstract: The African wildcat is one of the closest ancestors to the domestic cat and is believed to have similar nutrient requirements, but research is lacking. The objective of this study was to determine the effects of feeding a high-protein extruded kibble diet vs. a raw meat diet on nutrient digestibility, nitrogen metabolism, and blood metabolite concentrations in African wildcats. Five wildcats were randomized onto either a high-protein (>50% crude protein) extruded kibble diet or a raw meat diet. The study was executed as a crossover design, with 21-d periods, consisting of a 16-d adaptation phase followed by a 4-d total fecal and urine collection phase. Cats were housed individually in metabolism cages and fed to maintain body weight (BW). A fresh fecal sample was collected for short-chain fatty acid (SCFA) and branched-chain fatty acid (BCFA) analyses. Blood was analyzed for serum chemistry and leptin concentration. Food intake (as is) did not differ (P>0.05) between diets. Food intake and fecal output (g/d DMB) were greater (P<0.05) when cats consumed the kibble diet. Protein digestibility was higher (P<0.05) when cats were fed the raw meat diet vs. the kibble diet. Nitrogen intake was greater (P<0.05) when cats consumed the kibble diet, and more (P<0.05) nitrogen was present in the feces; however, the percentage of nitrogen retained and nitrogen balance did not differ (P>0.05). Fecal scores, ammonia, SCFA, and BCFA concentrations did not differ (P>0.05) between diets. Fecal butyrate molar ratio was higher (P<0.01) when cats consumed the kibble diet. Blood analyses demonstrated few differences between diets, but alanine aminotransferase activity and bicarbonate were higher (P<0.05) when cats consumed the commercial raw meat diet. Owing to lack of differences, these data indicate that African wildcats can readily utilize a high protein extruded kibble diet, and may be able to replace a commercial raw meat diet.
Abstract: Twelve young adult (1.7 +/- 0.1 yr) male cats were used in a replicated 3 x 3 Latin square design to determine the effects of fiber type on nutrient digestibility, fermentative end products, and fecal microbial populations. Three diets containing 4% cellulose, fructooligosaccharides (FOS), or pectin were evaluated. Feces were scored based on the 5-point system: 1 being hard, dry pellets, and 5 being watery liquid that can be poured. No differences were observed (P > 0.100) in intake of DM, OM, CP, or acid-hydrolyzed fat; DM or OM digestibility; or fecal pH, DM%, output on an as-is or DM basis, or concentrations of histamine or phenylalanine. Crude protein and fat digestibility decreased (P = 0.079 and 0.001, respectively) in response to supplementation with pectin compared with cellulose. Both FOS and pectin supplementation resulted in increased fecal scores (P < 0.001) and concentrations of ammonia (P = 0.003) and 4-methyl phenol (P = 0.003). Fecal indole concentrations increased (P = 0.049) when cats were supplemented with FOS. Fecal acetate (P = 0.030), propionate (P = 0.035), and total short-chain fatty acid (P = 0.016) concentrations increased in pectin-supplemented cats. Fecal butyrate (P = 0.010), isobutyrate (P = 0.011), isovalerate (P = 0.012), valerate (P = 0.026), and total branched-chain fatty acids + valerate (P = 0.008) concentrations increased with supplementation of FOS and pectin. Fecal cadaverine (P < 0.001) and tryptamine (P < 0.001) concentrations increased with supplementation of FOS and pectin. Fecal tyramine concentrations decreased (P = 0.039) in FOS-supplemented cats, whereas spermidine concentrations increased (P < 0.001) in pectin-supplemented cats. Whereas fecal concentrations of putrescine (P < 0.001) and total biogenic amines (P < 0.001) increased with FOS and pectin, the concentrations of these compounds were increased (P < 0.001) in cats supplemented with pectin. Fecal Bifidobacterium spp. concentrations increased (P = 0.006) and Escherichia coli concentrations decreased (P < 0.001) in FOS-supplemented cats. Fecal concentrations of Clostridium perfringens (P < 0.001), E. coli (P < 0.001), and Lactobacillus spp. (P = 0.030) also increased in pectin-supplemented cats. In addition to increasing populations of protein-fermenting microbiota, pectin increased production of fermentative end products associated with carbohydrate compared with protein fermentation. Pectin and FOS may be useful fiber sources in promoting intestinal health of the cat.
Abstract: The liver plays a central role in nutrient and xenobiotic metabolism, but its functionality declines with age. Senior dogs suffer from many of the chronic hepatic diseases as elderly humans, with age-related alterations in liver function influenced by diet. However, a large-scale molecular analysis of the liver tissue as affected by age and diet has not been reported in dogs.
Abstract: We have previously reported the effects of age and diet on nutrient digestibility, intestinal morphology, and large intestinal fermentation patterns in healthy young adult and senior dogs. However, a genome-wide molecular analysis of colonic mucosa as a function of age and diet has not yet been performed in dogs.
Abstract: The mechanisms contributing to BW gain following ovariohysterectomy in domestic cats are poorly understood. Moreover, the effects of food restriction to maintain BW following spaying have been poorly studied. Thus, our primary objective was to determine the effects of spaying and food restriction to maintain BW on adipose and skeletal muscle mRNA abundance and activity levels in cats. After a 4-wk baseline period (wk 0), 8 adult (approximately 1.5 yr old) domestic shorthair cats were spayed and fed to maintain BW for 12 wk. After 12 wk, cats were fed ad libitum for an additional 12 wk. Body composition was determined, activity levels were measured, and adipose and muscle biopsies were collected at wk 0, 12, and 24. Fasting blood samples were collected at wk 0, 6, 12, 18, and 24. To maintain BW post-spay, food intake was decreased (P < 0.05) by 30%. During this phase, mRNA abundance of adipose tissue lipoprotein lipase and leptin was decreased (P < 0.05), representing only 52 and 23% of baseline expression, respectively. Interleukin-6 mRNA, however, was increased (P < 0.05) 2-fold. Physical activity was decreased (P < 0.05) by wk 12, most dramatically during the dark period (approximately 20% of baseline activity). During ad libitum feeding (wk 12 to 24), food intake, BW, body fat percentage, and total fat mass were greatly increased (P < 0.05). Compared with wk 0, circulating leptin concentrations tended to increase (P < 0.10) by wk 18 and 24 (4.45 vs. 10.02 and 9.14 ng/mL, respectively), whereas glucose (91 vs. 162 mg/dL) and triacylglyceride (30 vs. 48 mg/dL) concentrations were increased (P < 0.05) by wk 24. Adipose tissue lipoprotein lipase, hormone sensitive lipase, and adiponectin mRNA were decreased (P < 0.05) at wk 24. Adipose interleukin-6 mRNA was increased (P < 0.05) at 24 wk. Physical activity was further decreased (P < 0.05) by wk 24, during the light (60% of baseline) and dark (33% of baseline) periods. In summary, spaying and food restriction affect physical activity levels and several genes associated with lipid metabolism (decreased lipoprotein lipase), food intake (decreased leptin expression), and insulin insensitivity (increased interleukin-6). By identifying these changes, targets for nutritional intervention or lifestyle management have been identified that may curb the risk of obesity and related disorders in spayed cats.
Abstract: We evaluated gene transcription in canine skeletal muscle (biceps femoris) using microarray analysis to identify effects of age and diet on gene expression. Twelve female beagles were used (six 1-year olds and six 12-year olds) and they were fed one of two experimental diets for 12 months. One diet contained primarily plant-based protein sources (PPB), whereas the second diet contained primarily animal-based protein sources (APB). Affymetrix GeneChip Canine Genome Arrays were used to hybridize extracted RNA. Age had the greatest effect on gene transcription (262 differentially expressed genes), whereas the effect of diet was relatively small (22 differentially expressed genes). Effects of age (regardless of diet) were most notable on genes related to metabolism, cell cycle and cell development, and transcription function. All these genes were predominantly down-regulated in geriatric dogs. Age-affected genes that were differentially expressed on only one of two diets were primarily noted in the PPB diet group (144/165 genes). Again, genes related to cell cycle (22/35) and metabolism (15/19) had predominantly decreased transcription in geriatric dogs, but 6/8 genes related to muscle development had increased expression. Effects of diet on muscle gene expression were mostly noted in geriatric dogs, but no consistent patterns in transcription were observed. The insight these data provide into gene expression profiles of canine skeletal muscle as affected by age, could serve as a foundation for future research pertaining to age-related muscle diseases.
Abstract: The objective of this study was to measure changes in body composition, physical activity and adipose and skeletal muscle gene expression of cats fed a high-protein (HP) diet or moderate-protein (MP) diet, following ovariohysterectomy. Eight cats were randomized onto HP or MP diets and were fed those diets for several months prior to baseline. All cats underwent an ovariohysterectomy at baseline (week 0) and were allowed ad libitum access to dietary treatments for 24 weeks. Food intake was measured daily, and BW and body condition score were measured weekly. Blood, adipose and skeletal muscle tissue samples were collected, physical activity was measured, and body composition was determined using DEXA (dual-energy X-ray absorptiometry) at weeks 0, 12 and 24. Caloric intake increased soon after ovariohysterectomy, resulting in increased (P < 0.05) BW at weeks 12 and 24 compared to week 0. Body condition score and body fat percentage increased (P < 0.05) over time. Blood glucose increased (P < 0.05) linearly over time. Non-esterified fatty acids were decreased (P < 0.05) at weeks 12 and 24 compared to week 0. Blood leptin increased (P < 0.05) over time. Total physical activity decreased (P < 0.05) from week 0 to weeks 12 and 24 in all cats. Adipose tissue mRNA abundance of adiponectin, hormone sensitive lipase, toll-like receptor-4, uncoupling protein-2 (UCP2) and vascular endothelial growth factor decreased (P < 0.05) linearly over time, regardless of diet. Skeletal muscle mRNA abundance for glucose transporter-1, hormone sensitive lipase and UCP2 were decreased (P < 0.05), regardless of dietary treatment. Our research noted metabolic changes following ovariohysterectomy that are in agreement with gene expression changes pertaining to lipid metabolism. Feeding cats ad libitum after ovariohysterectomy is inadvisable.
Abstract: The objective of the present study was to measure the differences in body composition, adipose tissue gene expression, blood metabolite and hormone concentrations, and insulin sensitivity in kittens exposed to high-protein (HP) or high-carbohydrate (HC) nutrition in utero and through the growth period. Eight dams were randomised onto two test diets, and fed the diets throughout gestation and lactation. Male offspring were evaluated for 9 months. Kittens were weaned at 2 months of age onto the same treatment diet as the dam and were allowed to consume diets ad libitum. The HC diet contained 34.3 % crude protein (CP), 19.2 % fat and 30.8 % digestible carbohydrate, while the HP diet contained 52.9 % CP, 23.5 % fat and 10.8 % digestible carbohydrate. Blood samples were collected at 6 months after birth. Body composition was determined at 2 and 8 months of age and an intravenous glucose tolerance test, neutering and adipose tissue biopsy conducted at 8 months of age. Physical activity was quantified at 6 and 9 months. Energy intake, DM intake and body weight were not different between groups. At 2 months, blood TAG were greater (P < 0.05) in kittens fed the HP diet. At 8 months, blood leptin was higher (P < 0.05) in kittens fed the HC diet, while chemokine receptor 5, hormone-sensitive lipase, uncoupling protein 2, leptin and insulin receptor mRNA were greater (P < 0.05) in kittens fed the HP diet. The present results demonstrate some of the changes in blood metabolites and hormones, physical activity and mRNA abundance that occur with feeding high protein levels to kittens.
Abstract: Maximizing health benefits of prebiotics, while limiting negative side effects, is of importance to the food industry. This study examined several oligosaccharides and their blends in an in vitro fermentation model. Substrates included medium- and long-chain fructooligosaccharides (FOS), oligofructose-enriched inulin, galactooligosaccharide, polydextrose (POL), and 50:50 substrate blends. Substrates and blends were fermented in vitro using human fecal inoculum, and fermentation characteristics were quantified at 0, 4, 8, and 12 hours. We hypothesized that mixtures of short- and long-chain oligosaccharides would generate less gas than do short-chain oligosaccharides and modulate gut microflora to a greater extent than do long-chain oligosaccharides. Carbohydrates blended with POL had decreased (P < .01) total gas volume and H(2) produced after 4, 8, and 12 hours of fermentation compared with individual carbohydrates. Mixing of 2 oligofructose-enriched inulin products led to less (P < .05) gas produced and a slower (P < .05) rate of production. When mixed with POL, all carbohydrates tested in the present study produced less total short-chain fatty acids (P < .04) and butyrate (P < .0001) after 12 hours of in vitro fermentation, compared with individual carbohydrates. The bifidogenic effect of medium-chain FOS and oligofructose-enriched inulin after 12 hours of in vitro fermentation was lower (P < .05) when mixed with POL. Mixing the pure carbohydrates with galactooligosaccharide increased (P < .05) bifidobacteria counts measured after 12 hours of in vitro fermentation, except when mixed with medium-chain FOS. In general, when mixed with POL, all carbohydrates had lower gas production, gas production rates, butyrate and total short-chain fatty acid production, and bifidobacteria counts than when fermented alone for 12 hours.
Abstract: The objective of this study was to identify qualitative and quantitative differences in microbial populations of adult cats fed diets containing different protein concentrations. Following a 4 week baseline period, eight healthy adult domestic short-hair queens (>1-year-old) were randomly allotted to a moderate-protein (MP; n = 4) or high-protein (HP; n = 4) diet for 8 weeks. Fresh faecal samples were collected after baseline and 8 weeks on treatment and stored at -80 degrees C. Following DNA extraction, samples were analyzed using denaturing gradient gel electrophoresis to distinguish qualitative changes between diets. Quantitative polymerase chain reaction was used to measure E. coli, Bifidobacterium, Clostridium perfringens, and Lactobacillus populations. Compared to baseline, cats fed MP had a bacterial similarity index of 66.7% as opposed to 40.6% similarity for those fed HP, exhibiting marked changes in intestinal bacteria of cats fed HP. Bifidobacterium populations were greater (p < 0.05) in cats fed MP versus HP (9.44 vs. 5.63 CFU/g). Clostridium perfringens populations were greater (p < 0.05) in cats fed HP than MP (12.39 vs. 10.83 CFU/g). In this experiment, a high-protein diet resulted in a dramatic shift in microbial populations. Decreased Bifidobacterium population in cats fed HP may justify prebiotic supplementation for such diets.
Abstract: Mechanisms contributing to age-related cognitive decline are poorly defined. Thus, we used canine microarrays to compare gene expression profiles of brain tissue from geriatric and young adult dogs. Cerebral cortex samples were collected from six geriatric (12-year old) and six young adult (1-year old) female beagles after being fed one of two diets (animal protein-based versus plant-protein based) for 12 months. RNA samples were hybridized to Affymetrix GeneChip Canine Genome Arrays. Statistical analyses indicated that the age had the greatest impact on gene expression, with 963 transcripts differentially expressed in geriatric dogs. Although not as robust as age, diet affected mRNA abundance of 140 transcripts. As demonstrated in aged rodents and humans, geriatric dogs had increased expression of genes associated with inflammation, stress response, and calcium homeostasis and decreased expression of genes associated with neuropeptide signaling and synaptic transmission. In addition to its existing strengths, availability of gene sequence information and commercial microarrays make the canine a powerful model for studying the effects of aging on cognitive function.
Abstract: Obesity is a major problem in today's dog population, with aged animals having an increased susceptibility to obesity-related comorbidities. A molecular approach to studying adipose tissue may enhance our understanding of its role in energy homeostasis and the disease process. Thus, the objective of this study was to use canine microarrays to compare gene expression profiles of adipose tissue from geriatric and young adult dogs. Adipose tissue samples were collected from six geriatric (12 year-old) and six young adult (one-year-old) female beagles after being fed one of two diets (animal protein-based vs. plant protein-based) for 12 months. RNA samples were hybridised to canine microarrays. Statistical analyses indicated that age had the greatest impact on gene expression, with 65 differentially expressed gene transcripts in geriatric dogs. Diet had a minor impact on gene expression, altering the expression of only 19 gene transcripts. In general, adipose tissue of geriatric dogs had increased expression of genes associated with cell cycle and growth, cell development and structure, cellular trafficking and protein processing, immune function, metabolism, and transcription and translation, as compared with that of young adults. Overall, our mRNA data suggest either an increased population of macrophages or increased inflammatory nature of adipocytes in adipose tissue of aged dogs.
Abstract: Nutrient digestibility has not been well characterized in exotic felids. The objective of this experiment was to evaluate differences in nutrient digestibility and fecal characteristics in five large exotic captive felid species, including bobcats, jaguars, cheetahs, Indochinese tigers, and Siberian tigers. All animals were individually housed and adapted to a beef-based raw diet (Nebraska Brand((R)) Special Beef Feline, North Platte, NE) for 16 d. Total fecal collections were conducted from days 17 to 20. Fecal samples were weighed and scored on collection. Diet and fecal samples were evaluated for dry matter, organic matter, protein, fat, and energy to determine total tract digestibility. Fresh fecal samples were collected to determine fecal pH, ammonia, phenol, indole, short-chain fatty acid, and branched-chain fatty acid concentrations. Fecal scores were greater (P<0.01) in Indochinese tigers when compared with all other species, and cheetahs had greater (P<0.01) fecal scores than jaguars and bobcats. Fat digestibility was greater (P<0.01) in Siberian tigers, Indochinese tigers, and bobcats (96%) compared with cheetahs and jaguars (94%). Digestible energy was greater (P<0.05) in bobcats and Indochinese tigers at 93.5 and 92.9%, respectively, compared with cheetahs and jaguars, 91.6%. Fecal pH was greater (P<0.01) in bobcats compared with all other species evaluated. Indole concentrations were greater (P<0.05) in cheetahs and jaguars compared with bobcats and Indochinese tigers. Fecal ammonia concentrations were increased (P<0.05) in cheetahs compared with all other species. The beef-based raw diet was highly digestible; however, differences in fat and digestible energy suggest that species should be considered when determining caloric needs of exotic felids. Zoo Biol 27:126-136, 2008. (c) 2008 Wiley-Liss, Inc.
Abstract: Dietary fibers may modulate insulin resistance and glucose homeostasis in dogs. Their efficacy is, however, dependent on their origin, physical properties, and fermentability in the large bowel. Eight healthy Beagle dogs were fed a commercial diet at twice their maintenance requirements until they became obese. They were then maintained in the obese state and used in a cross-over design study to evaluate the effects of short-chain fructooligosaccharide (scFOS) supplementation (1% wt:wt dry matter in the diet). The euglycemic hyperinsulinemic clamp technique was performed before and after fattening and at the end of each 6-wk cross-over period. Fat tissue biopsies were taken in food-deprived and postprandial phases to measure mRNA abundance of genes involved with fatty acid, glucose metabolism, or inflammation. Insulin resistance appeared progressively with fattening and the rate of glucose infusion during euglycemic clamp was lower (P < 0.05) at the end of the fattening period (7.39 mg.kg(-1).min(-1)) than at baseline (21.21 mg.kg(-1).min(-1)). In stable obese dogs, scFOS increased (P < 0.05) the rate of glucose infusion compared with control (7.77 vs. 4.72 mg.kg(-1).min(-1)). Plasma insulin and triglyceride concentrations were greater in obese than in lean dogs but were not altered by scFOS. Whereas mRNA was not affected in food-deprived dogs, scFOS increased uncoupling protein 2 (P = 0.05) and tended to increase carnitine palmitoyl transferase 1 adipose mRNA levels during the postprandial period (P = 0.09). Adding 1% scFOS to the diet of obese dogs decreases insulin resistance and appears to modulate the transcription of genes involved in fatty acid or glucose metabolism.
Abstract: Our objective was to examine the effects of fructan supplementation on the immune response of weanling puppies subjected to bacterial challenge. Previous studies in bacterial challenged neonatal piglets have reported benefits of fructan supplementation. Thirty hound-cross puppies (12 wk of age) were used in a 2 x 3 factorial randomized complete block design. Following a 7-d baseline period, puppies were assigned to diets containing: 1) no prebiotic, 2) 1% short-chain fructooligosaccharides (scFOS), or 3) 1% inulin. After 14 d on treatment diet, dogs received an oral gavage of: 1) Salmonella typhimurium DT104 (5 x 10(8) colony forming units) or 2) 0.9% saline. Food intake, fecal and activity scores, body temperature, body weight, blood chemistry, intestinal nutrient transport, intestinal morphology and pathology, and gut microbiota were measured. Food intake decreased (P < 0.01) and body temperature increased (P < 0.05) in infected puppies. However, the decrease in food intake was less (P < 0.05) in those consuming fructans. Infected puppies consuming fructans also had decreased (P = 0.05) severity of enterocyte sloughing than those fed the control diet. Ileal Na+-dependent glucose transport was decreased (P = 0.02) in infected vs. noninfected puppies consuming CON, whereas no changes occurred in fructan-supplemented animals. Puppies consuming inulin also had increased fecal acetate (P = 0.03) and total short-chain fatty acid (P = 0.06) concentrations than scFOS-fed puppies and controls. Finally, puppies fed inulin had an increase (P = 0.05) in Lactobacillus concentrations compared with scFOS and CON. In summary, fructan supplementation appeared to attenuate some of the negative responses associated with Salmonella challenge and may provide protection against infection in weanling puppies.
