Active fractions of mannoproteins derived from yeast cell wall stimulate innate and acquired immunity of adult and elderly dogs

F S A Kroll; T C Putarov; L Zaine; K S Venturini; C G Aoki; J P F Santos; V Pedrinelli; T H A Vendramini; M A Brunetto; A C Carciofi

doi:10.1016/j.anifeedsci.2020.114392

Active fractions of mannoproteins derived from yeast cell wall stimulate innate and acquired immunity of adult and elderly dogs

Anim Feed Sci Technol. 2020 Mar:261:114392. doi: 10.1016/j.anifeedsci.2020.114392. Epub 2020 Jan 10.

Authors

Affiliations

¹ Department of Veterinary Clinic and Surgery, Sao Paulo State University, Jaboticabal, Brazil.
² Department of Animal Nutrition and Production, University of Sao Paulo, Pirassununga, Brazil.
³ Department of Veterinary Clinic, University of Sao Paulo, São Paulo, Brazil.

Abstract

Nutritional 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 (H₂O₂) 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 H₂O₂ 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 age on faecal IgA content in dogs. This study suggests beneficial effects of mannoproteins on the specific and nonspecific immune responses in adult and elderly dogs.

Keywords: AFM, active fraction of mannoproteins; ALP, alkaline phosphatase; ALT, alanine aminotransferase; Ageing; CBC, complete blood count; CD21+, B lymphocyte; CD4+, auxiliary T lymphocyte; CD5+, total T lymphocyte; CD8+, cytotoxic lymphocyte; CO, cells only; Canine; DCHT, delayed cutaneous hypersensitivity test; FOSs, fructooligosaccharides; GALT, gut-associated lymphoid tissue; IL-12, interleukin 12; IgA, immunoglobulin A; Immunosenescence; LPS, bacterial lipopolysaccharide; MOSs, mannanoligosaccharides; NADPH, reduced nicotinamide adenine dinucleotide phosphate; NO, nitrogen monoxide; NOS, nitric oxide synthase; OD, optical density; PMA, phorbol myristate acetate; Saccharomyces cerevisiae; Senescence; TNF-α, tumour necrosis factor alpha; Th1, helper T lymphocyte.