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

Abstract

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.

Learning machine approach reveals microbial signatures of diet and sex in dog

“…Modification of gut microbiota in response to dietary treatments have been observed also at other taxonomic levels in healthy dogs. Algya et al (2018) [ 34 ] reported an increase of genus Clostridium in dogs fed with a commercial extruded diet, in comparison to dogs fed with a raw meat diet and a commercial moist diet. On the contrary, Bermingham et al (2017) [ 39 ] observed a decrease of Clostridium in dogs fed with a commercial extruded diet in comparison to the raw meat diet.…”

“…In the study of Mori et al (2019) [33], a low fat high protein diet caused a reduction of Bacteroidetes and an increase of Fusobacteria. Algya et al (2018) [34] reported a significant increase of Bacteroidetes and Fusobacteria and a decrease of Firmicutes in raw diet, based on chicken and sweet potatoes, in comparison to kibble diet. Indeed, the increase of Fusobacteria RA in the W diet was in agreement with these authors, but not for Bacteroidetes, which showed a very low RA in the H diet, that contains the highest lipid content (Table 2).…”

The Effects of Nutrition on the Gastrointestinal Microbiome of Cats and Dogs: Impact on Health and Disease

“…While RMBD diets are generally not recommended by most major veterinary and public health organizations due to the potential for pathogen contamination ( American Animal Hospital Association, 2011 ; American Veterinary Medical Association, 2012 ; Centers for Disease Control and Prevention, 2017 ; Food and Drug Administration, 2018 ), they are increasingly popular. Numerous studies have shown that animals fed RMBDs differ in GI microbiome composition and metabolism compared to those fed extruded, heat-processed foods ( Kerr et al, 2012 , 2014 ; Herstad et al, 2017 ; Kim et al, 2017 ; Sandri et al, 2017 ; Algya et al, 2018 ; Schmidt et al, 2018 ; Butowski et al, 2019 ). For example, dogs fed a RMBD exhibited more diverse and abundant microbes in the gut compared with those fed commercial foods; however, as the authors pointed out, dogs fed an RMBD may have a greater risk of opportunistic infection than those fed commercial foods ( Kim et al, 2017 ).…”

Effect of different starch sources in a raw meat-based diet on fecal microbiome in dogs housed in a shelter

“…Modification of gut microbiome in dogs has been investigated also in relation to dietary factors ( Kerr et al., 2013 , Middelbos et al., 2010 , Panasevich et al., 2013 , Panasevich et al., 2015 , Roehe et al., 2016 , Sandri et al., 2017 , Stercova et al., 2016 ), suggesting that the variability of microbial population can be associated to specific ingredients or nutrients. These studies have allowed to gather more insight on the composition of fecal microbiota, useful in digestibility trials ( Algya et al., 2018 , Kieler et al., 2017 ) and in diet formulation.…”

“…However, the starch-to-lipid ratio in the diet did caused a shift of microbial communities in the feces of dogs. Several other factors affect the gut microbiome as the extent of thermal treatments of food ( Algya et al., 2018 ) and the administration of raw meat ( Beloshapka et al., 2011 , Bermingham et al., 2017 , Kim et al., 2017 , Sandri et al., 2017 ), prebiotics ( Swanson et al., 2002 ) and source of protein ( Sandri et al., 2019 ).…”