The yeast cell wall (YCW) preparation, Safmannan, was evaluated as a dietary supplement for adult dogs. Using a 5 x 5 Latin square design with 14-d periods, adult dogs cannulated in the terminal ileum were supplemented with 0, 0.05, 0.25, 0.45, or 0.65% YCW based on daily food allowance. Apparent ileal nutrient digestibility responded cubically (P = 0.07 to 0.10) to YCW supplementation. Ileal nutrient digestibility tended (P = 0.09) to be greater with YCW supplementation compared with control. Apparent total tract digestibility responded cubically (P < 0.05) to YCW supplementation. Total white blood cell and eosinophil counts tended (P < 0.09) to decrease quadratically with YCW supplementation, with the lowest counts at the 0.25% supplementation level, whereas monocyte counts decreased (P < 0.05) linearly with YCW supplementation. Serum immunoglobulin A (IgA) concentrations tended (P = 0.09) to respond cubically to YCW, with the lowest value at the 0.25% supplementation level. Ileal IgA tended (P < 0.09) to respond quadratically, with the greatest ileal IgA concentration at 0.25% YCW. Using serial dilution and plating enumeration techniques, fecal Escherichia coli concentrations decreased linearly (P = 0.01) with YCW supplementation, whereas Clostridium perfringens responded cubically (P = 0.09). Cubic trends were noted for E. coli (P = 0.10) and lactobacilli (P = 0.08) concentrations, as evaluated by quantitative PCR analysis. Total fecal DNA was most similar to the control treatment at 0.25% YCW. Although the effects on immunological indices appear limited, our results suggest that YCW supplementation in dogs at less than 1% may affect ileal and total tract nutrient digestibility, and the colonization of the gut by E. coli may be decreased.

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.

Phytoestrogen-rich soy is known to ameliorate menopause-associated obesity and metabolic dysfunction for reasons that are unclear. The gut microbiota have been linked with the development of obesity and metabolic dysfunction. We aimed to determine the impact of soy on cardiometabolic health, adipose tissue inflammation, and the cecal microbiota in ovariectomized (OVX) rats bred for low-running capacity (LCR), a model that has been previously shown to mimic human menopause compared to sham-operated (SHM) intact control LCR rats. In this study, soy consumption, without affecting energy intake or physical activity, significantly improved insulin sensitivity and body composition of OVX rats bred for low-running capacity. Furthermore, soy significantly improved blood lipid profile, adipose tissue inflammation, and aortic stiffness of LCR rats. Compared to a soy-free control diet, soy significantly shifted the cecal microbial community of LCR rats, resulting in a lower Firmicutes:Bacteroidetes ratio. Correlations among metabolic parameters and cecal bacterial taxa identified in this study suggest that taxa Prevotella, Dorea, and Phascolarctobacterium may be taxa of interest. Our results suggest that dietary soy ameliorates adiposity, insulin sensitivity, adipose tissue inflammation, and arterial stiffness and exerts a beneficial shift in gut microbial communities in a rat model that mimics human menopause.

Despite their popularity, little research has been performed on lightly cooked and raw diet formats for pets. Therefore, the objective of this study was to determine the apparent total tract macronutrient digestibility (ATTD); fecal characteristics, metabolites, and microbiota; serum chemistry metabolites; urinalysis; and voluntary physical activity levels of adult dogs fed commercial diets differing in processing type. The diets included: 1) Extruded Dry Kibble (EXT) diet; 2) High-Moisture Roasted Refrigerated (RR) diet; 3) High-Moisture Grain-Free Roasted Refrigerated (GFRR) diet; and 4) Raw (RAW) diet. Eight dogs (mean age = 3.6; mean BW = 13.0 kg) were used in a replicated 4x4 Latin square design. Each period consisted of 28 d, with a 14-d adaptation phase followed by a 7-d phase for measuring voluntary physical activity, 1-d adaptation phase to metabolic cages, 5-d phase for fecal and urine collection, and 1 d for blood collection. Except for microbiota, all data were analyzed statistically by mixed models using SAS. Microbiota data were analyzed using Quantitative Insights Into Microbial Ecology (QIIME) and Statistical Analyses of Metagenomic Profiles (STAMP) software. Many differences in digestibility were observed, including greater (P<0.05) ATTD of crude protein and fat in dogs fed GFRR and RR than dogs fed EXT. Dogs fed RAW had the lowest fecal pH and dry matter %, but fecal scores were not affected. Dogs fed RR had higher (P<0.05) fecal indole and total phenol and indole concentrations than dogs fed the other diets. Dogs fed RAW had a higher (P<0.05) fecal ammonia concentration than dogs fed the other diets. Fecal microbial diversity was altered by diet, with dogs fed GFRR and RAW having reduced species richness than dogs fed EXT. Dogs fed RR, GFRR, or RAW had lower (P<0.05) Actinobacteria and higher (P<0.05) Fusobacteria than dogs fed EXT. Dogs fed RAW or GFRR had higher (P<0.05) Proteobacteria than dogs fed EXT or RR. Dogs fed RAW had higher (P<0.05) Bacteroidetes and lower (P<0.05) Firmicutes than dogs fed EXT. Serum triglycerides were within reference ranges, but greater (P<0.05) in dogs fed EXT than dogs fed GFRR and RAW. All diets were well tolerated and dogs remained healthy throughout the study. In conclusion, the lightly cooked and raw diets tested were highly palatable, highly digestible, reduced blood triglycerides, maintained fecal quality and serum chemistry, and modified the fecal microbial community of healthy adult dogs.

BackgroundThe importance of upper airway structure in the susceptibility of the lower respiratory tract to colonization with potential pathogens is well established. With the advent of rapid, high throughput, next generation sequencing, there is a growing appreciation of the importance of commensal microbial populations in maintaining mucosal health, and a realization that bacteria colonize anatomical locations that were previously considered to be sterile. While upper respiratory tract microbial populations have been described, there are currently no published studies describing the normal microbial populations of the bovine lower respiratory tract. Consequently, we have little understanding of the relationship between upper and lower respiratory tract microbiota in healthy cattle. The primary objective of our study was to characterize the composition, structure and relationship of the lower and upper respiratory microbial communities in clinically healthy feedlot cattle. Nasopharyngeal swabs (NPS), and bronchoalveolar lavage (BAL) fluid, were collected from clinically healthy feedlot calves (n = 8). Genomic DNA from each sample was extracted, and the V3-V4 hypervariable region of the bacterial 16S rRNA gene was amplified and sequenced using Illumina Miseq platform.ResultsAcross all samples, the most predominant phyla were Proteobacteria, Actinobacteria and Firmicutes. The most common genera were Rathayibacter, Mycoplasma, Bibersteinia and Corynebacterium. The microbial community structure was distinct between these two biogeographical sites. Most of the bacterial genera identified in the BAL samples were also present in the NPS, but biogeographical-specific genera were enriched in both the NPS (Rathayibacter) and BAL (Bibersteinia) samples. There were strong associations between the presence of certain taxa at each specific location, and strong correlations between the presence of specific taxa in both the NPS and BAL samples.ConclusionsThe correlation between the presence of specific taxa in both the NPS and BAL samples, supports the notion of a mutualistic interrelationship between these microbial communities. Future studies, in large cohorts of animals, are needed to determine the role and clinical importance of the relationships of respiratory tract microbial communities with health, productivity, and susceptibility to the development of respiratory disease, in growing cattle.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-017-1042-2) contains supplementary material, which is available to authorized users.

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Because obesity is associated with many co-morbidities, including diabetes mellitus, this study evaluated the second-meal effect of a commercial prebiotic, inulin-type fructans, and the effects of the prebiotic on faecal microbiota, metabolites and bile acids (BA). Nine overweight beagles were used in a replicated 3×3 Latin square design to test a non-prebiotic control (cellulose) against a low (equivalent to 0·5 % diet) and high dose (equivalent to 1·0 % diet) of prebiotic over 14-d treatments. All dogs were fed the same diet twice daily, with treatments provided orally via gelatin capsules before meals. On days 13 or 14 of each period, fresh faecal samples were collected, dogs were fed at 08.00 hours and then challenged with 1 g/kg body weight of maltodextrin in place of the 16.00 hours meal. Repeated blood samples were analysed for glucose and hormone concentrations to determine postprandial incremental AUC (IAUC) data. Baseline glucose, insulin and active glucagon-like peptide-1 levels were similar between all groups (P>0·10). Glucose and insulin IAUC after glucose challenge appeared lower following the high dose, but did not reach statistical relevance. Prebiotic intervention resulted in an increase in relative abundance of some Firmicutes and a decrease in the relative abundance of some Proteobacteria. Individual and total faecal SCFA were significantly increased (P<0·05) following prebiotic supplementation. Total concentration of excreted faecal BA tended to increase in dogs fed the prebiotic (P=0·06). Our results indicate that higher doses of inulin-type prebiotics may serve as modulators of gut microbiota, metabolites and BA pool in overweight dogs.

Human-grade (HG) pet foods are commercially available, but they have not been well studied. Our objective was to determine the apparent total tract digestibility (ATTD) of HG pet foods and evaluate their effects on fecal characteristics, microbiota, and metabolites, serum metabolites, and hematology of dogs. Twelve dogs (mean age=5.5±1.0; BW=11.6±1.6 kg) were used in a replicated 4×4 Latin square design (n=12/treatment). The diets included: 1) Chicken and Brown Rice Recipe (extruded; Blue Buffalo); 2) Roasted Meals Tender Chicken Recipe (fresh; Freshpet); 3) Beef & Russet Potato Recipe (HG beef; JustFoodForDogs); and 4) Chicken & White Rice Recipe (HG chicken; JustFoodForDogs). Each period consisted of 28 d, with a 6-d diet transition phase, 16 d of consuming 100% of the diet, a 5-d phase for fecal collection, and 1 d for blood collection. All data were analyzed using the Mixed Models procedure of SAS 9.4. Dogs fed the extruded diet required a higher (P&lt;0.05) daily food intake (dry matter basis; DMB) to maintain BW. The ATTD of dry matter (DM), organic matter (OM), energy, and acid-hydrolyzed fat (AHF) were greater (P&lt;0.05) in dogs fed the HG diets than those fed the fresh diet, and greater (P&lt;0.05) in dogs fed the fresh diet than those fed the extruded diet. Crude protein ATTD was lower (P&lt;0.05) for dogs fed the extruded diet than those fed all other diets. Dogs fed the extruded diet had greater (P&lt;0.05) fecal output (as-is; DMB) than dogs fed fresh (1.5-1.7 times greater) or HG foods (2.0-2.9 times greater). There were no differences in fecal pH, scores, and metabolites, but microbiota were affected by diet. Dogs fed HG beef had higher (P&lt;0.05) relative abundance of Bacteroidetes and lower (P&lt;0.05) relative abundance of Firmicutes than dogs fed the fresh or HG chicken diets. The Actinobacteria, Fusobacteria, Proteobacteria, and Spirochaetes phyla were unchanged (P&gt;0.05), but diet modified the relative abundance of nearly 20 bacterial genera. Similar to previous reports, these data demonstrate that the fecal microbiota of dogs fed HG or fresh diets is markedly different than those consuming extruded diets, likely due to ingredient, nutrient, and processing differences. Serum metabolites and hematology was not greatly impacted by diet. In conclusion, the HG pet foods tested resulted in significantly reduced fecal output, were highly digestible, maintained fecal characteristics, serum chemistry, and hematology, and modified the fecal microbiota of dogs.