Rendimiento de los pollos de engorde y respuesta de fase aguda en función del estrés térmico y la suplementación de lignanos en la dieta

Resumen

In poultry production heat stress (HS) is a major environmental challenge negatively affecting production performance, FCR, bird health and welfare. Due to their genetic potential for high growth rates, modern broiler genetics are particularly susceptible to elevated HS. Several botanical compounds, including lignans from trees may have potential to alleviate negative effects of HS in poultry. The objective of this study was to determine the effects of dietary supplementation with wood-derived lignans on performance and acute phase response in broilers subjected to thermoneutral conditions or HS. 264 day-old Cobb 500 males were randomly assigned to 2 dietary treatments (Control diet vs. Control + lignans, agromed®ROI, agromed Austria GmbH; 400 g/t) with 12 pens/treatment and 11 birds/replicate. Birds were fed a starter diet until 21 days of age under thermoneutral conditions (23±1 °C). From 22-35 days of age, birds received a finisher diet and 6 pens of each treatment continued to be kept under thermoneutral conditions, whereas the other 6 pens were subjected to HS conditions, where ambient temperature was increased to 34±1 °C for 6 hours/day at a relative humidity between 65-75 %. Diets were based on corn and soybean meal. Data were subjected to two-way ANOVA using the GLM procedure of SAS, using diet, temperature and their interaction as main effects. Duncan’s multiple range test modelled comparisons among multiple means. Mortality was analyzed by chi-squared test. The results were considered statistically significant at P<0.05. Implementation of HS impacted all experimental parameters (P<0.05), proving an effective challenge model. Including lignans reduced mortality under thermoneutral conditions (3 vs. 10 %, P<0.05), but reduced mortality under HS conditions only numerically. Under HS conditions, lignan supplementation improved FCR (1.49 vs. 1.56, P<0.05). Serum concentrations of acute phase proteins were reduced in heat-stressed birds in response to lignan supplementation (2.5 vs. 3.5 mg/ml for ceruloplasmin; 54.4 vs. 102.8 mg/ml for alpha-1-acid glycoprotein, P<0.05). Since both proteins are synthesized in the liver in response to tissue damage related to inflammatory and oxidative challenge, lignans may have a modulating effect on the inflammatory and oxidative stress response. In conclusion, wood lignans have potential to support performance and health under conditions of HS in commercial broilers, hence contributing to productivity and animal welfare.