Effects of probiotic supplementation and postmortem storage condition on the oxidative stability of M. Pectoralis major of laying hens.

Dietary probiotic supplementation is a promising alternative to antibiotics in the poultry industry, and some studies have found its positive impacts on meat quality attributes. The objective of this study was to evaluate the effects of dietary treatments on oxidative stability of postmortem chicken fillet (M. Pectoralis major) muscles during 7 d of storage under either high oxygen (HIOX) or vacuum (VAC) conditions. A total of 264 Hy-Line Brown laying hens (11 birds per cage) were assigned to 2 different dietary treatments (regular diet or 300 ppm probiotic, Sporulin enhanced diet) before being sacrificed. At 17 wk, one bird per cage from 6 cages per treatment was randomly selected and slaughtered (n = 12). Chicken fillets from both sides were collected and randomly assigned to HIOX or VAC conditions. Within each fillet side, the muscle was divided into 3 portions, assigned to 1 or 7 d storage period, while the caudal portion was allocated as the 0 d samples for proximate composition and fatty acid profiling. Results revealed that the muscle crude compositions were not altered in laying hens that were fed probiotic supplementary diet compared to controls (P > 0.05). However, the muscle samples from probiotic fed laying hens had higher proportions of unsaturated fatty acid (74.76 vs. 71.65%, P < 0.05) and 2-thiobarbituric acid reactive substances (0.79 vs. 0.67 mg malondialdehyde/kg meat, P < 0.05) than the samples from the control. In addition, the probiotic fed laying hens, but not controls, had higher levels of conjugated dienes (3.32 vs. 2.63 μg/g meat) and peroxides (0.40 vs. 0.30 milliequivalent O2/kg fat) in the muscle samples after 7 d of storage (P < 0.05). The results from the present study indicated that postmortem fillet muscles obtained from the laying hens fed with probiotic supplementation would be more prone to be oxidized, especially under more oxidizing conditions (HIOX and extended storage time).