Apparent total-tract macronutrient digestibility, serum chemistry, urinalysis, and fecal characteristics, metabolites and microbiota of adult dogs fed extruded, mildly cooked, and raw diets1.

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 4 × 4 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 CP and fat in dogs fed GFRR and RR than dogs fed EXT. Dogs fed RAW had the lowest fecal pH and DM %, 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.

Algya KM ，Cross TL ，Leuck KN ，Kastner ME ，Baba T ，Lye L ，de Godoy MRC ，Swanson KS ... -  《-》

Apparent total tract macronutrient digestibility of mildly cooked human-grade vegan dog foods and their effects on the blood metabolites and fecal characteristics, microbiota, and metabolites of adult dogs.

Vegan, mildly cooked, and human-grade dog foods are becoming more popular, as beliefs and views of pet owners change. To our knowledge, however, dog studies have not examined the digestibility of commercial vegan diets. Therefore, the objective of this study was to determine the apparent total tract digestibility (ATTD) of mildly cooked human-grade vegan dog foods and their effects on blood metabolites and fecal microbiota, characteristics, and metabolites of adult dogs consuming them. Three commercial dog foods were tested. Two were mildly cooked human-grade vegan dog diets, while the third was a chicken-based extruded dog diet. Twelve healthy adult female beagles (7.81 ± 0.65 kg; 7.73 ± 1.65 yr) were used in a replicated 3 × 3 Latin Square design. The study consisted of three experimental periods, with each composed of a 7 d diet adaptation phase, 15 d of consuming 100% of the diet, a 5 d phase for fecal collection for ATTD measurement, and 1 d for blood collection for serum chemistry and hematology. During the fecal collection period, a fresh sample was collected for fecal scoring and dry matter, pH, metabolite, and microbiota measurements. All data were analyzed using the Mixed Models procedure of SAS (version 9.4). All three diets were shown to be highly digestible, with all macronutrients having digestibility values above 80%. The vegan diets had higher (P < 0.001) ATTD of fat, but lower (P < 0.05) ATTD of organic matter than the extruded diet. Dogs consuming the vegan diets had lower circulating cholesterol (P < 0.001), triglyceride (P < 0.001), and platelet (P < 0.009) concentrations and lower (P < 0.010) blood neutrophil percentages than dogs consuming the extruded diet. Dogs consuming vegan diets had lower (P < 0.001) fecal dry matter percentages, lower (P < 0.001) fecal phenol and indole concentrations, and higher (P = 0.05) fecal short-chain fatty acid concentrations than those consuming the extruded diet. Fecal bacterial alpha and beta diversities were not different (P > 0.05) among diets, but dogs consuming vegan diets had altered (P < 0.05) relative abundances of nearly 20 bacterial genera when compared with those consuming the extruded diet. In conclusion, the mildly cooked human-grade vegan dog foods tested in this study performed well, resulting in desirable fecal characteristics, ATTD, and serum chemistries. The vegan diets tested also led to positive changes to serum lipids and fecal metabolites, and interesting changes to the fecal microbial community.

Roberts LJ ，Oba PM ，Swanson KS 《-》

Nutrient digestibility and fecal characteristics, microbiota, and metabolites in dogs fed human-grade foods.

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 and Russet Potato Recipe (HG beef; JustFoodForDogs); and 4) Chicken and 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 < 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 < 0.05) in dogs fed the HG diets than those fed the fresh diet, and greater (P < 0.05) in dogs fed the fresh diet than those fed the extruded diet. Crude protein ATTD was lower (P < 0.05) for dogs fed the extruded diet than those fed all other diets. Dogs fed the extruded diet had greater (P < 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 < 0.05) relative abundance of Bacteroidetes and lower (P < 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 > 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 were not greatly affected 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.

Do S ，Phungviwatnikul T ，de Godoy MRC ，Swanson KS ... -  《-》

Evaluation of high-protein diets differing in protein source in healthy adult dogs.

Given the dynamic market for protein-based ingredients in the pet food industry, demand continues to increase for both plant- and animal-based options. Protein sources contain different amino acid (AA) profiles and vary in digestibility, affecting protein quality. The objective of this study was to evaluate the apparent total tract digestibility (ATTD) of canine diets differing in protein source and test their effects on serum metabolites and fecal characteristics, metabolites, and microbiota of healthy adult dogs consuming them. Four extruded diets were formulated to be isonitrogenous and meet the nutrient needs for adult dogs at maintenance, with the primary difference being protein source: 1) fresh deboned, dried, and spray-dried chicken (DC), 2) chicken by-product meal (CBPM), 3) wheat gluten meal (WGM), and 4) corn gluten meal (CGM). Twelve adult spayed female beagles (body weight [BW] = 9.9 ± 1.0 kg; age = 6.3 ± 1.1 yr) were used in a replicated 4 × 4 Latin square design (n = 12/treatment). Each period consisted of a 22-d adaptation phase, 5 d for fecal collection, and 1 d for blood collection. Fecal microbiota data were analyzed using QIIME 2.2020.8. All other data were analyzed using the Mixed Models procedure of SAS version 9.4. Fecal scores were higher (P < 0.05; looser stools) in dogs fed DC or CBPM than those fed WGM or CGM, but all remained within an appropriate range. Dry matter ATTD was lower (P < 0.05) in dogs fed CBPM or CGM than those fed DC or WGM. Crude protein ATTD was lower (P < 0.05) in dogs fed DC or CGM than those fed WGM. Dogs fed CBPM had lower (P < 0.05) organic matter, crude protein, and energy ATTD than those fed the other diets. Fecal indole was higher (P < 0.05) in dogs fed CBPM than those fed WGM. Fecal short-chain fatty acids were higher (P < 0.05) in dogs fed DC than those fed CGM. Fecal branched-chain fatty acids were higher (P < 0.05) in dogs fed DC or CBPM than those fed WGM. Fecal ammonia was higher (P < 0.05) in dogs fed DC or CBPM than those fed WGM or CGM. The relative abundances of three bacterial phyla and nine bacterial genera were shifted among treatment groups (P < 0.05). Considering AA profiles and digestibility data, the DC diet protein sources provided the highest quality protein without additional AA supplementation, but the animal-based protein diets resulted in higher fecal proteolytic metabolites. Further studies evaluating moderate dietary protein concentrations are needed to better compare plant- and animal-based protein sources.

Sieja KM ，Oba PM ，Applegate CC ，Pendlebury C ，Kelly J ，Swanson KS ... -  《-》

Dietary supplementation with fiber, "biotics," and spray-dried plasma affects apparent total tract macronutrient digestibility and the fecal characteristics, fecal microbiota, and immune function of adult dogs.

A variety of functional ingredients, including fibers, prebiotics, probiotics, and postbiotics may be added to pet foods to support gastrointestinal and immune health. While many of these ingredients have been tested individually, commercial foods often include blends that also require testing. This study was conducted to evaluate the effects of diets containing blends of fibers, "biotics," and/or spray-dried plasma on apparent total tract digestibility (ATTD), stool quality, fecal microbiota and metabolites, and immune health outcomes of adult dogs. A total of 12 healthy adult intact English pointer dogs (6 M, 6 F; age = 6.4 ± 2.0 yr; BW = 25.8 ± 2.6 kg) were used in a replicated 3 × 3 Latin square design to test diets formulated to: 1) contain a low concentration of fermentative substances (control diet, CT); 2) be enriched with a fiber-prebiotic-probiotic blend (FPPB); and 3) be enriched with a fiber-prebiotic-probiotic blend + immune-modulating ingredients (iFFPB). In each 28-d period, 22 d of diet adaptation was followed by a 5-d fecal collection phase and 1 d for blood sample collection. All data were analyzed using SAS 9.4, with significance being P < 0.05 and trends being P < 0.10. FPPB and iFPPB diets led to shifts in numerous outcome measures. Dry matter (DM), organic matter, fat, fiber, and energy ATTD were lower (P < 0.01), fecal scores were lower (P < 0.01; firmer stools), and fecal DM% was higher (P < 0.0001) in dogs fed FPPB or iFPPB than those fed CT. Serum triglycerides and cholesterol were lower (P < 0.01) in dogs fed FPPB or iFPPB than those fed CT. Fecal protein catabolites (isobutyrate, isovalerate, indole, and ammonia) and butyrate were lower (P < 0.05), while fecal immunoglobulin A (IgA) was higher (P < 0.01) in dogs fed FPPB and iFPPB than those fed CT. Fecal microbiota populations were affected by diet, with alpha-diversity being lower (P < 0.05) in dogs fed iFPPB and the relative abundance of 20 bacterial genera being altered in dogs fed FPPB or iFPPB compared with CT. The circulating helper T cell:cytotoxic T cell ratio was higher (P < 0.05) in dogs fed iFPPB than those fed CT. Circulating B cells were lower (P < 0.05) in dogs fed FPPB than those fed iFPPB, and lower (P < 0.05) in dogs fed iFPPB than those fed CT. Our results demonstrate that feeding a fiber-prebiotic-probiotic blend may provide many benefits to canine health, including improved stool quality, beneficial shifts to fecal microbiota and metabolite profiles, reduced blood lipids, and increased fecal IgA.

Lee AH ，Lin CY ，Do S ，Oba PM ，Belchik SE ，Steelman AJ ，Schauwecker A ，Swanson KS ... -  《-》