Yeast-purified beta-1,3/1,6-glucans (BG) can modulate dogs’ immune systems and microbiome, but the optimal inclusion dose remains unknown. The aim of the study was to evaluate the effects of 0.0, 0.07, 0.14, and 0.28% inclusion of BG in a dry extruded diet on the digestibility, immunity, and fecal microbiota of healthy adult dogs. Eight male and female border collies [n = 4; body condition score (BCS) = 5] and English cocker spaniels (n = 4; BCS = 5), aged 3.5 ± 0.5 years, were randomly distributed into two 4 × 4 balanced Latin squares. Fecal microbiota (using 16S rRNA sequencing, Illumina^®), apparent digestibility coefficients (ADC) of nutrients, fecal concentrations of short-chain fatty acids (SCFA) and branched-chain fatty acids (BCFA), ammoniacal nitrogen, lactic acid, IgA and pH, lymphocyte immunophenotyping, intensity and percentage of phagocytosis and oxidative burst were determined. No differences were observed in Faith (p = 0.1414) and Pielou-evenness (p = 0.1151) between treatments, but beta diversity was different between 0.0% and 0.14% BG groups (p = 0.047). Moreover, the Firmicutes phylum was the most abundant in all groups and exhibited the highest relative abundance after the consumption of 0.14% BG, a finding considered beneficial for the canine microbiome. The Erysipelotrichaceae and Ruminococcaceae families, along with the Faecalibacterium and Prevotella genera, considered favorable for their involvement in butyrate production and other metabolites, showed increased abundance after the consumption of 0.14% BG. The potentially pathogenic Proteobacteria phylum displayed lower abundance after the consumption of 0.14% BG. Fecal concentrations of the evaluated compounds and pH did not differ after consumption of the BG at all percentages. Higher crude protein ADC was found after 0.14 and 0.28% BG consumption (p < 0.0001), but no differences were found for other nutrients. Phagocytosis, oxidative burst, and lymphocyte populations were not modulated by any of the treatments; however, 0.14% BG modulated the lymphocyte T CD4⁺:CD8⁺ ratio (p = 0.0368), an important marker of immune system efficiency. The inclusion of 0.14% BG resulted in the best responses and was the best dose evaluated.

One of the most studied functional foods in dog feed today is the prebiotic. Prebiotics are known for their modulating effects on the intestinal microbiota, fecal characteristics, and the immune system, which promotes beneficial effects to the host. However, with the diversity of prebiotics in the pet market, there are discussions around which prebiotics to use to stimulate these positive effects. In this case, the objective of this review was to demonstrate the main effects of different prebiotics on the feeding of healthy dogs. Platforms such as Embase, PubMed, and Mendeley were accessed to plot all scientific articles in vivo that reported prebiotics to feed adult or senior dogs. After excluding duplicate articles and without the evaluated criteria, we obtained a total of 36 articles. Our results demonstrated the diversity and concentrations of prebiotics in the feeding of healthy adult and senior dogs. The effects of prebiotics differ according to source, concentration, and length of the supplementation period. Several beneficial effects of different prebiotics have been observed in dogs, such as increased fecal Lactobacilli and Bifidobacteria concentrations and decreased fecal Clostridium perfringens and Escherichia coli concentrations, increased short chain fatty acids concentrations, decreased colonic ammonia absorption, and immunomodulatory effects, such as improved humoral immune response and increased phagocytic index. Galactooligosaccharides, fructooligosaccharides, mannanoligosaccharides, yeast cell wall, inulin, and beta-glucans were the most studied prebiotics, which showed potentially promising effects. This is a review that brings the importance and the modulating effects of prebiotics in the feeding of healthy dogs; the effects help the gastrointestinal tract and the immune system.

Prebiotics promote health benefits, however, there is no consensus on the minimal intake period required in order to obtain good results. This study evaluated the effect of the time of ingestion of prebiotics on fecal fermentation products and immunological features in dogs. Twenty-four adult dogs were randomly distributed in a block design with six groups and four treatments. Diet and intake period were variation factors. Diets were either a control diet without the addition of prebiotic (CO) or with the inclusion of 1% of a commercial product containing a minimum of 0.38% galactooligosaccharides (GOS), 0.5% (B1) or 1% (B2) of a prebiotic blend. Time variable was set at 30 and 60 days for evaluation of immunity and gut health. Results were analyzed in the Statistical Analysis System software (SAS), version 9.4, considering the repeated measures over time design, and means were compared by the Tukey test and p < 0.05 was significant. Propionic acid was the only variable that had an interaction effect, with reduction of this metabolite in treatment B2 in the period of 60 days. At T60, concentrations of immunoglobulin A, lactic acid, and pH in the feces increased (p < 0.05) in all treatments regardless of prebiotic inclusion or not. GOS increased fecal score and lactic acid concentrations. Therefore, a 60-day intake period of a prebiotic blend was not sufficient to modulate fecal and immune variables and higher concentrations of a single prebiotic would be more relevant for results.

Docosahexaenoic acid (DHA) has an important role in brain development and functionality. Therefore, this study aimed to evaluate the effects of DHA-concentrated fish oil on the cognitive function of puppies. Twelve 3-month-old puppies were included, blocked by breed and randomly distributed into two groups: the Control Group (CG), without supplementation, and the Experimental Group (EG), supplemented with 40 mg DHA/kg BW/day. The object discrimination test was used, with a normal stage (NS) and a reverse stage (RS), and blood samples were collected to evaluate the serum polyunsaturated fatty acid (PUFA) concentration and total antioxidant capacity (TAC) before (T0) and 30 (T1), 60 (T2) and 90 (T3) days after beginning the study. For the NS, there were effects of treatment (p = 0.0039) and time (p < 0.0001), in which the correct answer frequency in the EG was higher than the CG. The serum eicosapentaenoic acid (EPA) + HA concentrations at T1, T2 and T3 were higher than at T0 for the EG (p = 0.0159), in addition, EG showed higher serum EPA + DHA concentrations than CG at T2 (p = 0.0245). The TAC values were similar between the groups (p = 0.3211). It was concluded that the cognitive function of puppies can be enhanced with DHA-concentrated fish oil supplementation without increasing the serum lipid oxidation.

Background: Homemade diets are a worldwide trend, and many recipes are currently available on websites but may not be considered balanced. This study aimed to evaluate if the number of ingredients, supplement, or vegetarian/vegan-only ingredients included in a recipe influence the nutrient content of homemade diets for dogs and cats. Chemical analyses were performed on 75 diets for dogs and 25 for cats prepared according to websites’ recipes, and minerals were analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES). Results: Canine diets that met fat requirements had more ingredients than those below recommendations. None of the cat diets met iron requirements, and feline diets that met requirements of manganese had fewer ingredients and those that supplied requirements of protein and sodium had more ingredients than the diets below recommendations (p < 0.05). Non-supplemented canine and feline diets had calcium and calcium:phosphorus ratio below recommendations (p < 0.05). Non-supplemented feline diets had lower sodium and iron, and zinc levels were below recommendation in diets for both species. Diets with animal products for dogs had higher levels of protein and zinc, although zinc was deficient in both groups, and there were higher amounts of crude fiber, magnesium, and manganese in vegetarian/vegan diets (p < 0.05). Diets with animal products for cats had higher levels of protein (p = 0.003), but there was a higher amount of crude fiber (p = 0.014) in vegetarian/vegan diets. Conclusion: The number of ingredients and vegetarian/vegan preparation did not guarantee nutritional adequacy of diets, and the presence of supplement did not ensure a balanced diet.

Coprophagia is a common and undesirable behavior observed in dogs; however, little is known about its causes or possible consequences when analysis of the animal’s feces is needed for experimental purposes. Therefore, this study evaluated the effect of coprophagy on digestibility, fecal pH, and fermentative metabolites. Twelve healthy dogs with a mean age of 3.50 ± 1.45 years were included and divided into two groups: coprophagic (COP) and non-coprophagic (NCOP). The study lasted 30 days, the last 6 days being used to collect feces for the analysis of the apparent digestibility of coefficients (ADC), fecal pH, and the concentration of short- and branched-chain fatty acids, ammonia, and fecal lactic acid. Statistical analysis was performed using the SAS software. No differences were observed for most variables, except for the ADC of nitrogen-free extract (NFE), which presented the highest average for the COP. This result should be interpreted with caution, as the NFE is estimated from calculations and was not determined in the laboratory; in addition, the results represent not only starch and sugars but also some parts referring to fibers. Therefore, coprophagy seemed not to influence the fecal variables analyzed.