Aflatoxin-Binding Saccharomyces cerevisiae RC016 Strain Improves Production Parameters In Vivo In Rats Fed Aflatoxin B1-Contaminated Feed

GONZALEZ PEREYRA, M.L.; TORRES, A.; PEREYRA, C.M; CHULZE, S.N; DALCERO, A.M; CAVAGLIERI, L.R

Ottawa

Congreso; Mycored North America; 2012

Carleston Unviersity, ISM

Yeast is frequently fed to livestock for its nutritional value in the form of culture, commercially formulated additives or included naturally in feedsuffs such as brewer¡¯s grains. Saccharomyces cerevisiae strain RC016 isolated from pig intestine, which was shown to bind AFB1 in vitro in previous studies, was evaluated in vivo for its ability to counteract detrimental AFB1 effects in Wistar rats. Thirty-six animals (male, 8 weeks old, similar weight) were kept in metabolic cages for 60 days. Six treatments (6 animals each) were applied: 1) uncontaminated feed control, 2) yeast control, 3) feed amended 40 ppb AFB1, 4) feed amended 100 ppb AFB1, 5) feed amended 40 ppb AFB1 + daily oral dose of 108 cells/ml S. cerevisiae and 6) feed amended 100 ppb AFB1 + daily oral dose of 108 cells/ml S. cerevisiae. Animals were fed 30g of feed per day and water ad libitum. Animals were weighed 3 times a week and the total weight gain (TWG), progressive weight gain (PWG), feed efficiency (FE) and feed conversion (FC) were calculated. Data was analyzed by the general linear and mixed model (GLMM) using InfoStat (version 2012) software, considering treatments as fixed effects and each animal, cage and weight registration as random effects. First order continuous autoregressive correlations were considered and the model was corrected to obtain variance homogeneity. The variation between means of each treatment was analyzed by the DGC test (P¡Ü0.05). Results showed that S. cerevisiae RC016 was able to improve all production parameters in animals fed 40 and 100 ppb AFB1, compared with animals that consumed the contaminated feed but were not administered the yeast and even control animals fed uncontaminated feed. Mean TWG was higher (P¡Ü0.05) in treatments 5 and 6 (103.50 and 101.17g, respectively) compared with other treatments. Mean PWG was also higher in treatments 5 and 6 (4.17 and 4.05 g). Feed efficiency and conversion followed the same tendency being significantly different in treatments 5 (FC 0.30; FE 3.21) and 6 (FC 0.30; FE 3.39). The beneficial effect may be due to the adsorption of the mycotoxin by the yeast cell wall in the intestine which reduces its bioability improving animal performance. The effect of this yeast to counteract AFB1 activity on several rat organs (liver, lungs, testicles, bone marrow) are being evaluated as well as the increment of AFB1 in the feces of yeast-treated rats due to in vivo AFB1 adsorption. These preliminary results indicate a potential use of strain RC016 for the formulation of feed additives destined to livestock.