Search

The objective of present study was to investigate the effects of alpha-lipoic acid (ALA) dietary supplementation on the behavior, physiological and oxidant stress indicators, and bone quality in broilers under high stocking density (HSD) stress. A total of one thousand eight hundred 22-day-old Arbor Acres male broiler chicks were randomly allocated to 18 pens (2.97 × 2.03 m) in 3 groups: 14 birds/m2 (NSD, normal stocking density) or 18 birds/m2 (HSD) or 18 birds/m2 plus 300 mg/kg ALA dietary supplement (HSD + ALA, high stocking density + alpha-lipoic acid). Each treatment had 6 replicates, and the experiment lasted 3 wk. The HSD group was significantly lower than the NSD group (P 0.05) in the standing and preening behavior, alkaline phosphatase activity, PTH concentration, H/L ratio, CAT, T-AOC, MDA, SOD, and GSH-Px. These results indicate that the increase of stocking density lowered the bone quality, increased the physiological and oxidative stress indicators, and modified the behavior of broilers, whereas ALA dietary supplementation could counteract the reduction in the performance and physiological responses of broilers under high-density environmental stress.

Objective The study was conducted to evaluate the effect of stocking density and alpha-lipoic acid (ALA) on the growth performance, feed utilization, carcass traits, antioxidative ability and immune response of broilers. Methods A total of 1530 22-day-old male broilers (Arbor Acres) with comparable body weights (731.92 ± 5.26) were placed into 18 cages (2.46 × 2.02 m) in groups of 75 birds (15 birds/m2, 37.5 kg/m2; LD, low stocking density), 90 birds (18 birds/m2, 45.0 kg/m2; HD, high stocking density) and 90 birds with 300 mg/kg ALA added to the basal diet (18 birds/m2, 45.0 kg/m2; HD+ALA, high stocking density + -lipoic acid); each treatment was represented by 6 replicates. The experimental period was 3 weeks. Results The results showed that the high stocking density regimen resulted in a decreased growth, feed conversion ratio, carcass weight, thigh yield and bursa weight relative to body weight (P < 0.05) on d 42. The abdominal fat yield in the HD+ALA group was lower (P = 0.031) than that of the LD group at 42 d. The superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in serum were increased, and malondialdehyde (MDA) content decreased after adding ALA product (P < 0.05) on d 42. Additionally, the serum concentrations of IgA and IgG were decreased (P < 0.05) and the level of diamine oxidase (DAO) was higher (P < 0.01) in the HD group on d 42. Conclusion The high stocking density significantly decreased broiler growth performance, feed utilization and carcass traits, increased physiological and oxidative stress and induced intestinal mucosal injury. The supplementation of ALA product in broiler diet at 300 mg/kg may reduce the adverse effects of high stocking density-mediated stress by maintaining the antioxidant system and humoral immune system.

Ammonia in poultry houses not only affects worker health but also induces a variety of poultry diseases. Alpha-lipoic acid (LA) is an effective antioxidant that protects cells against oxidative injury during various toxic and pathological processes. This study was designed to evaluate the mitigating effects of LA supplementation on ammonia stress and hepatic proteome changes in broilers. Male broilers (22 d old) were allocated to 3 groups: (1) a control group without ammonia stress (CTRL); (2) exposure to 70 ppm ammonia (AM); and (3) exposure to 70 ppm ammonia and dietary administration of 300 mg/kg LA (AM+LA). Ammonia exposure significantly decreased broiler growth performance and plasma glutathione peroxidase activity (P 0.05), and increased plasma malondialdehyde content and glutamic-pyruvic transaminase activity (P 0.05). These negative effects were eliminated by LA supplementation. Comparative proteomic analyses revealed 291 differentially expressed proteins in the AM group compared to the CTRL and AM+LA groups. A total of 30 proteins were differentially expressed between the AM/CTRL and (AM+LA)/AM groups. The addition of LA restored 24 of these proteins to control levels; these proteins were mainly related to transcription regulation, detoxification, protein translation and degradation, and immune and stress responses. The differentially expressed proteins included the high mobility group box (HMGB) and glutathione S-transferase (GST), which is closely related to immune response and oxidative stress, and collagens, which are implicated in liver injury. The addition of LA to broiler diet may reduce ammonia toxicity by maintaining the antioxidant system, xenobiotic metabolism, and metabolic pathways.