Growth performance and antioxidant response of broiler chicken fed oxidized lipids with or without phytogenic feed additives.

The aim of this study was to test the in vivo antioxidant capacity in broilers of two phytogenic additives, one derived from olive pomace (OE) and an encapsulated product based on Capsicum sp., black pepper, and ginger (SPICY), in a challenge using oxidized lipids in the feed. A total of 720 one-day-old male Cobb 500 were allocated to 72 pens (8 treatments, 9 replicates, 10 birds/replicate). The treatments were arranged in a 2 × 2 × 2 factorial, the factors being: fat source (4% soybean oil or 4% peroxidized soybean oil); SPICY (0 or 250 ppm); and OE (0 or 3077 ppm). From 1 to 21 days (global period) no significant differences were observed on performance. Broilers fed peroxidized oil showed higher plasma ferric reducing antioxidant power (FRAP; P < 0.05) values and higher catalase (CAT) activity compared to those fed fresh oil except in those birds fed the OE which remained constant with both oil sources (P < 0.05 for the interaction). Broilers fed OE showed a significant lower CAT gene expression in the liver (P < 0.05). Moreover, the heat shock protein 70 (HSP70) gene expression was lower in birds fed fresh oil and OE compared to those fed fresh oil without OE but higher in birds fed peroxidized oil and OE compared to those fed peroxidized oil without OE (P < 0.05 for the interaction). By contrast, broilers fed SPICY upregulated CAT (P < 0.05) and downregulated HSP70 (P < 0.05) gene expression in the liver compared to those not supplemented with SPICY. In conclusion, feeding broilers with peroxidized soybean oil from 1 to 21 days of age did not affect the productive parameters. However, the presence of lipid peroxidation products in the feed triggered both non-enzymatic and enzymatic antioxidant responses to maintain the oxidant/antioxidant balance. In the case of birds fed the OE, the enzymatic antioxidant response was more attenuated, indicating a better control of oxidative stress, likely mediated by HSP70.