title: Effect of dietary γ-aminobutyric acid on laying performance, egg quality, immune activity and endocrine hormone in heat-stressed Roman hens.
abstract: This study was conducted to evaluate the effect of γ-aminobutyric acid (GABA) on laying performance, egg quality, digestive enzyme activity, hormone level and immune activities in Roman hens under heat stress. Roman hens (320 days old) were fed with 0, 25, 50, 75 and 100 mg/kg GABA, respectively during a 60-day experiment. Compared with control, supplementation of 50 mg/kg GABA improved the laying performance and egg quality by significantly increasing egg production, average egg weight and shell strength (P < 0.05), while decreasing the feed-egg ratio and cholesterol level. Anti-oxidation activity was improved by significantly increasing the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), but decreasing malondialdehyde level in serum (P < 0.05), while significantly increasing the glucose and total protein (TP) level, follicle stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E(2) ), insulin, triiodothyronine (T(3) ) and free triiodothyronine (FT(3) ) levels, and IgG, IgA and complement (C3)activity in serum (P < 0.05). The results indicated that oral GABA improved laying performance and physical condition mainly by modulating hormone secretion, enhancing anti-oxidation and immune activity, and maintaining electrolyte balance. Fifty mg/kg was the optimum level for laying hens under heat stress in the present study.
authors.affiliation: Feed Science Institute, College of Animal Science, Zhejiang University Hangzhou, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Xiao-Ting
authors.initials: XT
authors.lastname: Zou
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Xin-Yang
authors.initials: XY
authors.lastname: Dong
authors.forename: Wenjing
authors.initials: W
authors.lastname: Zhao
mesh_terms: D000821:Animal Feed; D000818:Animals; D002645:Chickens / Q000276:immunology* / Q000502:physiology*; D019587:Dietary Supplements; D004531:Eggs; D004702:Endocrine Glands / Q000378:metabolism; D005260:Female; D006358:Hot Temperature / Q000009:adverse effects*; D010058:Oviposition / Q000502:physiology*; D018384:Oxidative Stress / Q000187:drug effects; D011897:Random Allocation; D013312:Stress, Physiological / Q000187:drug effects / Q000276:immunology / Q000502:physiology*; D014882:Water-Electrolyte Balance; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage* / Q000494:pharmacology
chemical_list: D005680:gamma-Aminobutyric Acid