Effects of Olive Pomace and Spice Extracts on Performance and Antioxidant Function in Broiler Chickens

This research aimed to evaluate the effects of an olive pomace extract (OE) and a fat-encapsulated extract composed of a blend of oleoresins from Capsicum sp., black pepper, and ginger (SPICY) on broiler chicken performance and antioxidant function. In total, 640 1-day-old male chicks were randomly assigned to five experimental diets (eight replicates/treatment, 16 birds/replicate). Diets included a basal diet with no added vitamin E (NC), NC plus 100 ppm of vitamin E (PC), NC plus 1250 ppm of OE, NC plus 250 ppm of (SPICY), and NC plus 1250 ppm OE plus 250 ppm of SPICY (SPIOE). Phytogenic additives were supplied by Lucta S.A., Spain. Compared to the NC, the PC significantly (p < 0.05) increased ADG from 8 to 14 days of age, with both OE and SPICY showing intermediate values between both controls. At the end of this trial, at 35 days of age, a significant (p < 0.05) increase in plasma GPx activity was observed in PC-fed birds compared to the NC, with no effects of malonyl dialdehyde (MDA) and total antioxidant capacity. Birds fed the OE and SPICY displayed intermediate values of GPx activity compared to both controls. The expression of heat shock protein 70 (HSP70) and glutathione S-Transferase Alpha 4 (GSTA4) was significantly lower (p < 0.05) in the jejunal mucosa of birds fed the OE compared to the NC. Moreover, the expression of HSP70 was significantly lower (p < 0.05) in birds fed the OE compared to SPICY but was not significantly different compared to the blend of both extracts (SPIOE). In conclusion, OE and SPICY were useful in maintaining growth performance in no vit E-supplemented diets, particularly in the case of OE mediated by its antioxidant action through HSP70.