Associação entre quitosana e ácidos graxos insaturados em dietas para bovinos

Abstract

This study aimed evaluate the assotiation effect between chitosan with soybean oil and whole soybean grain on nutrients intake and aparent digestibillity, rumen fermentation, nitrogen balance, microbial protein synthesis,blood metabolites, ingestive behavior and ruminal kinetics in catlle. Five Simental x Zebu crossbred heifers, ruminally cannulated, with approximately 24 months of age, initial body weight of 335 ± 53.2 kg were randomly distributed in a 5 × 5 Latin square experimental design to receive one of the five experimental diets: 1) CON = Control (without inclusion of unsatured fatty acid (FA) or chitosan); 2) SO = Soybean Oil (dietary inclusion at 2,5% in total dry matter (DM); 3) WS = Whole raw soybean (dietary inclusion at 16% in total DM); 4) CHSO = Chitosan + Soybean Oil (dietary inclusion at 0,2% and 2,5% in total DM, respectively); 5) CHWS = Chitosan + Soybean Grain (dietary inclusion at 0,2% and 16% in total DM, respectively). The forage source was maize silage and the additive was provided on topdress form. The OS and GS diets, regardless of the addition of chitosan, decreased the nutrient intakes, except for the ether extract (EE), which was higher (P<0.05) in animals fed with UFA sources. Diets with UFA reduced the digestibility of neutral detergent fiber (NDF) and increased the EE (P<0.05). Diets with UFA and CHI increased rumen pH and reduced the concentration of ammoniacal nitrogen (P<0.05). In addition, in general, diets with UFA and CHI reduced the total production of short- chain FA, acetate, propionate and butyrate, in Mmol. Diets with UFA reduced nitrogen intake and excretion (N), while CHI increased and retention and efficiency in the use of N (P<0.05). CHI reduced triglycerides and VLDL blood levels (P <0.05). Diets with UFA decreased reticular flow of DM, NDF and potentially digestible NDF (pd) in relation to the control group (P<0.05). Diets with SO and WS, regardless of the addition of chitosan, decreased the DM digestion rate, ruminal turnover of DM, NDF and passage of DM, NDF and NDFpd in relation to animals fed the control diet. Diets with AGI do not interfere on nutrients digestibility, however, they reduce the consumption and use of ruminal N and alter fermentation and ruminal kinetics. On the other hand, CHI has no effect on intake, digestibility of nutrients and feeding behavior, but alters the use of N and rumen fermentation to a more energetically efficient route in diets for beef heifers.