Ácido benzoico e óleos essenciais em rações de leitões desafiados com E. coli K88+

Abstract

Studies evaluating the additive action mechanism, such as benzoic acid and essential oils are a quest to minimize the wear of bowel function of weanling pigs, and replace antibiotic growth promoters. The object of this study was to evaluate the effect of association of benzoic acid (AB) and essential oils (OE) on the performance and intestinal health of weanling pigs challenged with E. coli K88 + . The experiment was conducted in the Swine Experimental Centre of Department of Animal Science, at the Federal University of Lavras. 270 piglets weaned at 21 days of age, with initial weight of 5.76 ± 0.52 kg, were used in a randomized blocks and distributed in six treatments: 1) Positive control receiving Colistin 40ppm (CP); 2) Negative control without additive (CN); 3) Negative control + 5g/kg of benzoic acid (AB); 4) Negative control + 2g/kg of benzoic acid and essential oils (AB+OE2); 5) Negative control + 3g/kg of benzoic acid and essential oils (AB+OE3); 6) Negative control + 4g/kg of benzoic acid and essential oils (AB+OE4). There were nine replications and five piglets per experimental plot. In the seventh and eighth day of the experiment all the animals were challenged with Escherichia coli K88 + (1 ml, 10 6 CFU/ml). The animals were weighed at the beginning, at 14, 21, 28 and 42 days experiment for performance evaluation. The fecal score evaluation was conducted twice a day to determine the incidence of diarrhea. Four days after challenge, stool samples were collected for microbial analysis. Fourteen days after the inoculation one animal for pen was slaughtered to evaluate pH, volatile fatty acids production, microbial population, intestinal morphology, cholecystokinin count, proliferating cells count and weight organs. The experiment lasted 42 days and at the end was evaluated the economic viability. The association of AB and OE in the 3g/kg inclusion resulted in better performance in the first two weeks compared to CN. In total period benzoic acid and associations in the 3g/kg and 4g/kg inclusions were similar (P > 0,05) to CP and above (P < 0,05) to CN for daily gain and final weight results. There was no difference (P > 0,05) on the incidence of diarrhea, microbial population, volatile fatty acids production, pH, organ weights, cell proliferation count and cholecystokinin count. The CN and AB+OE4 had higher villus height (P < 0,05) than the AB+OE3 group. The net revenue was higher (P < 0,05) for AB, AB+OE3 and AB+OE4 than CN and was similar (P > 0,05) CP. use of benzoic acid and associations in medium and high levels resulted in higher economic returns than the use of basal diet, enabling the inclusion of these. Thus, the combination of additives in the 3g/kg inclusions provides improved post weaning performance, and is an economically viable alternative to Colistin replacement.