Summary The effects of exogenous enzymes supplementation on kibble diets for dogs formulated with soybean meal (SBM) as a substitute for poultry by‐product meal (PM) was investigated on nutrient digestibility, fermentation products formation, post‐prandial urea response and selected faecal bacteria counts. Two kibble diets with similar compositions were used in two trials: PM‐based diet (28.9% of PM; soybean hulls as a fibre source) and SBM‐based diet (29.9% of SBM). In experiment 1, the SBM diet was divided into three diets: SBM‐0, without enzyme addition; SBM‐1, covered after extrusion with 7500 U protease/kg and 45 U cellulase/kg; and SBM‐2, covered with 15 000 U protease/kg and 90 U cellulase/kg. In experiment 2, the SBM diet was divided into three diets: SBM‐0; SBM‐1, covered with 140 U protease/kg; 8 U cellulase/kg, 800 U pectinase/kg, 60 U phytase/kg, 40 U betaglucanase/kg and 20 U xylanase/kg; and SMB‐2, covered with 700 U protease/kg, 40 U cellulase/kg, 4000 U pectinase/kg, 300 U phytase/kg, 200 U betaglucanase/kg and 100 U xylanase/kg. Each experiment followed a block design with six dogs per diet. Data were submitted to analysis of variance and means compared by orthogonal and polynomial contrasts (p < 0.05). In both experiments, nutrients and energy digestibility did not differ between diets (p > 0.05). SBM consumption resulted in increased faecal moisture and production (p < 0.05), without effect on faecal score. Higher concentration of propionate, acetate and lactate, and lower ammonia and pH were found in the faeces of dogs fed SBM (p < 0.05). Higher post‐prandial urea was verified in dogs fed SBM (p < 0.05). In experiment 2, the addition of enzymes increased faecal concentration of propionate, acetate and total short‐chain fatty acid (p < 0.05) and tended to reduce post‐prandial urea concentration (p = 0.06). Although with similar digestibility, SBM shows a worse utilization of absorbed amino acids than the PM. Soybean oligosaccharides can beneficially change gut fermentation product formation. Enzymes can increase the gut fermentation activity and improve the SBM proteic value.

Data comparing age-related alterations in faecal IgA concentrations of dogs are not available in the literature. The present study aimed to compare the faecal concentrations of IgA in puppies, mature and senior dogs. A total of twenty-four beagle dogs were used, including eight puppies (5 months old, four females and four males), eight mature (4·6 years old, eight males) and eight senior dogs (10·6 years old, three males and five females). Fresh faecal samples were collected from each dog for three consecutive days and pooled by animal. After saline extraction, IgA content was measured by ELISA. Data were analysed by one-way ANOVA, and means were compared with Tukey's test (P,0·05). Results showed that puppies have lower faecal IgA concentrations than mature dogs (P,0·05); senior animals presented intermediary results. The reduced faecal IgA concentration in puppies is consistent with the reduced serum and salivary IgA concentrations reported previously, suggesting a reduced mucosal immunity in this age group. Although some studies have found an increased serum IgA concentration in older dogs, this may differ from the intestinal secretion of IgA, which appears to be lower in some senior animals (four of the eight dogs studied).

The effects of age on microbiota composition, gut fermentation end-product formation and peripheral lymphocyte numbers were compared between old and young adult Beagle dogs fed four kibble diets differing in yeast cell wall contents. The experiment had a double 4 £ 4 Latin square design, one with four mature dogs (4 years old) and the other with four old dogs (10 years old), with four replicates (diets) per dog. In each period a 15 d adaptation period preceded a 5 d total collection of faeces for the digestibility trial. On day 21, fresh faecal samples were collected for the determination of bacterial enumeration, pH, biogenic amine and short-chain fatty acid. Flow cytometry was used for immunophenotypic evaluation. Dogs were fed four kibble diets with similar composition with 0, 0·15, 0·30 and 0·45 % of yeast cell wall (as-fed), respectively. Data were evaluated using general linear models of Statistical Analysis Systems statistical software (P,0·05). No evidence of a difference in faecal bacteria counts between ages was found (total aerobes, total anaerobes, Bifidobacterium, Lactobacillus, Clostridium and Escherichia coli: P.0·15). Faecal concentrations of butyrate, histamine, agmatine and spermine were lower (P#0·05) and faecal pH was higher (P¼0·03) in older dogs than in mature adult dogs, suggesting an alteration in bacterial metabolic activity, or in the rate of intestinal absorption of these compounds. Concentrations of T-lymphocytes, T-cytotoxic lymphocytes and B-lymphocytes were also lower (P#0·01) in older dogs than in mature adult dogs. The study confirmed alterations in peripheral lymphocytes and revealed a reduced concentration of some fermentation end products in the colon of old dogs.

ResumoTem-se observado o uso crescente de nutracêuticos em medicina veterinária, para auxiliar no tratamento clínico. Esta revisão teve como objetivo descrever alguns nutracêuticos que atuam sobre a imunidade de cães e gatos e levantar os possíveis benefícios como tratamento adjuvante para determinadas enfermidades. A ação de derivados de levedura tem sido bastante avaliada, especialmente da fração beta-glucano, um potente imunomodulador, com ação já demonstrada em cães e gatos, sendo benéfico no tratamento de algumas doenças. Os ácidos graxos poliinsaturados ômega-3, talvez os mais utilizados atualmente, podem trazer benefícios no tratamento de hipertensão, doenças renais e cardíacas, artrites, doenças autoimunes, doenças gastrintestinais e câncer. A vitamina E apresenta ação antioxidante e imunomoduladora, podendo auxiliar no tratamento de doenças dermatológicas e hepatobiliares. O uso de carotenoides, que tem ação semelhante à da vitamina E, pode ser interessante por serem potentes antioxidantes, podem ajudar na melhora da resposta imune contra microrganismos e, também, na prevenção do aparecimento de tumores. Apesar de ainda serem necessários mais estudos clínicos para se entender os reais benefícios trazidos pela suplementação dos nutracêuticos em cada doença específica, a compreensão dos mecanismos de ação destes indica que são promissores para uso clínico. Palavras-chave: Ácidos graxos poliinsaturados ômega-3, Beta-glucano, carotenoides, imunidade, vitamina E AbstractThe use of nutraceuticals in veterinary medicine is growing and is assumed that they could aid in clinical treatment. This review aims to describe some nutraceuticals that act on the immunity of dogs and cats and show the possible benefits as an adjuvant treatment for some diseases. The action of some yeast derivates as immunomodulators, especially the beta-glucan fraction, was already proved to occur in dogs and cats, being beneficial as an adjuvant therapy in many clinical conditions. Omega-3 polyunsatured fatty acids, possibly the mostly used nutraceuticals, can improve the condition in some diseases, such as hypertension, renal, cardiac, gastrointestinal and autoimmune diseases, arthritis and cancer. Vitamin E has antioxidant and immunomodulatory action and can aid in the treatment

A B S T R A C TNutritional intervention in older dogs aims to increase lifespan and improve life quality as well as delay the development of diseases related to ageing. It is believed that active fractions of mannoproteins (AFMs) obtained through extraction and fractionation of yeast cell walls (Saccharomyces cerevisiae) may beneficially modulate the immune system. However, studies that have evaluated this component and the effects of ageing on the immune system of dogs are scarce. This study aimed to evaluate the immunological effects of AFMs in adult and elderly dogs. Three extruded iso-nutrient experimental diets were formulated: without addition of AFM (T0); with AFM at 400 mg/kg (T400); and with AFM at 800 mg/kg (T800). Thirty-six beagle dogs were used, and six experimental treatments, resulting in combinations of age (adult and elderly) and diet (T0, T400, and T800), were evaluated. On days zero, 14, and 28, blood samples were obtained for leucocyte phenotyping and phagocytosis assays. On days zero and 28, a lymphoproliferation test, quantification of reactive oxygen (H 2 O 2 ) and nitrogen (NO) intermediate production, evaluation of faecal immunoglobulin A (IgA) content, and a delayed cutaneous hypersensitivity test (DCHT) were performed. Statistical analyses were performed with SAS software. Repeated measure variance analyses were performed, and means were compared by the Tukey test. Values of P ≤ 0.05 were considered significant, and values of P ≤ 0.10 were considered tendencies. Dogs fed T400 tended to have higher neutrophilic phagocytic activity than dogs fed T800 (P = 0.073). Regarding reactive oxygen intermediates, bacterial lipopolysaccharide (LPS)-stimulated neutrophils from animals that were fed T400 had a tendency to produce more H 2 O 2 than those from animals fed the control diet (P = 0.093). Elderly dogs, when compared to adult dogs, had lower absolute T and B lymphocyte counts, lower auxiliary T lymphocyte counts, and higher cytotoxic T lymphocyte counts (P < 0.05). A significant effect of diet, age, and time with saline inoculation was noted for the DCHT. There was no effect of diet or