Effect of wheat bran feruloyl oligosaccharides on the performance, blood metabolites, antioxidant status and rumen fermentation of lambs

The objective of this experiment was to investigate the effects of wheat bran feruloyl oligosaccharides (FOs) as an antioxidant supplement on performance, blood metabolites, antioxidant status and ruminal fermentation of lambs. Fifty, two-month-old crossbred male lambs (Dorper x Small-tail Han Sheep) with an initial body weight (BW) of 20.21 +/- 3.36 kg were randomly assigned into five groups of ten animals each and fed basal diet with dietary wheat bran FOs supplementation at 0, 50, 100, 200 and 400 mg/kg feed, respectively. The experimental period lasted 56 days and was preceded by an adaption period of 14 days. The absorption spectrum of FOs product used in this study revealed the presence of an esterified feruloyl group. The esterified FA concentration of this product reached 0.99 mmol/g. The feed conversion ratio improved quadratically (P < 0.05) with increasing FOs supplementation at stage from 29-56 days and over the whole experiment. During 29-56 days, the average daily gain of the lambs receiving 100 and 200 mg/kg FOs tended to be higher than lambs receiving 400 mg/kg FOs (P = 0.06). The apparent digestibility of dry matter (DM), organic matter (OM), crude protein (CP) and neutral detergent fiber (NDF) were significantly reduced when lambs were fed the 400 mg/kg FOs diet (P < 0.05). Supplementing lambs with 50, 100 and 200 mg/kg FOs significantly increased serum concentrations of total protein (P < 0.05), meanwhile, the serum albumin concentration of treatment groups showed a tendency to be higher than the control group (P = 0.05). Serum total antioxidative capacity (T-AOC) tended to increase (P = 0.07) quadratically with increasing FOs supplementation, and glutathione peroxidase (GSH-Px) activity increased (P < 0.05) quadratically with increasing doses of FOs. Compared to the control group, the serum catalase (CAT) and superoxide dismutase (SOD) activity of lambs fed with the 50 and 100 mg/kg FOs diet was significantly (P < 0.05) higher. FOs-supplementation groups had higher serum glutathione (GSH) concentrations than the control (P < 0.05). In addition, the ruminal ammonia nitrogen concentration of lambs fed with the 200 mg/kg FOs diet tended to be lower (P = 0.07) than lambs fed with the 400 mg/kg FOs diet, but the concentrations of total volatile fatty acid (VFA), individual VFA and pH were not affected. These results demonstrated that FOs supplementation can promote growth performance, decrease ruminal ammonia nitrogen concentration and improve antioxidant properties by increasing antioxidant enzyme activities and GSH concentration in lambs. Therefore, wheat bran FOs could be used as a novel antioxidant for lamb diets.