Purified lignin and capsaicnoids supplementation for broiler chickens

Two experiments were conducted to evaluate the effects of lignin and capsaicinoids (CAP) supplementation on the performance and physiological responses of broiler chickens. In the first experiment, the effects of dietary supplementation with purified lignin on performance,relative organ weights, serum metabolites, and gene expression profiles of broilers subjected to cyclic heat stress (HS) were evaluated. At 22 days of age, 280 broilers were allocated in a completely randomized design with four treatments, ten replicates, and seven birds per experimental unit. The birds were subjected to daily cyclic HS, with a temperature of 32 °C (±1) for 10 h/day (08:00–18:00 h) and a temperature of 22 °C (±1) for the rest of the time. The treatments consisted of a basal diet or a basal diet with the addition of 5, 10, or 15 g of purified lignin/kg of diet. There was no effect (P > 0.05) of lignin supplementation on performance, carcass yield, relative weights of the bursa, spleen, and liver, or serum levels of glucose, triglycerides, uric acid, malondialdehyde, triiodothyronine, or tetraiodothyronine. The abundance of mRNA for heat shock protein 70, nuclear factor-κB, glutathione peroxidase, and Cu,Zn superoxide dismutase in the liver was also not affected (P > 0.05) by the treatments. In the second experiment, the effects of dietary CAP supplementation on performance, intestinal morphometry, and gene expression of LPS-challenged broilers were evaluated. At 8 days of age, 144 male broilers (Cobb 500) were allocated in a completely randomized design with three treatments, eight replicates, and six birds per experimental unit. The treatments consisted of a control diet (CON), a control diet with LPS administration (CON+LPS), and a control diet supplemented with 1 mg CAP/kg of diet and LPS administration (CAP+LPS). The LPS challenge consisted of intraperitoneal injections at 14, 16, 18, and 20 days of age. Four hours after the LPS injection at 20 days, one bird per experimental unit was sacrificed for serum and jejunum sample collection, which were used for mRNA analysis. The performance of the birds was evaluated at 21 days of age. The CON birds showed higher feed intake (P = 0.011) and better feed conversion ratio (P = 0.022) compared to CON+LPS birds. The CAP+LPS birds showed higher body weight gain compared to CON+LPS birds, but lower than CON birds (P <0.001). The CON+LPS birds had greater crypt depth than CON and CAP+LPS birds (P = 0.002).There was no significant treatment effect on villus height (P > 0.05). Higher mRNA expression of superoxide dismutase (P = 0.046) and catalase (P = 0.011) was observed in the jejunum of CON birds compared to CON+LPS birds. It was concluded that supplementation with 1 mg CAP/kg of diet improves growth performance and intestinal morphometry of LPS-challenged broilers, while purified lignin supplementation does not improve performance, or the antioxidant response of broilers subjected to HS. Keywords: Additive; Antioxidants; Immune Response