Effect of dietary γ-aminobutyric acid on performance parameters and some plasma metabolites in Cherry Valley ducks under high ambient temperature

Gamma aminobutyric acid (GABA) is one of the inhibitory neurotransmitters that may have the ability torelieve the intensity of stress. Heat stress remains a major threat for duck production in summer in most areas of China. The current study was conducted to investigate the effect of dietary GABA on performanceparameters and plasma metabolites of heat exposed ducks. Two thousand Cherry Valley ducks (19 d) wererandomly divided into two groups, each group with five replicates. One group was fed basal diet and theother fed basal diet with 100 mg/kg GABA for 42 days. The ambient temperature from day 19 to 42 was 29.7 ± 3.5°C. Growth performance and rectal temperature were determined on days 19, 32 and 42. Plasmasamples were collected at day 42. The results showed that dietary GABA had no significant effect on ducks’rectal temperature but decreased the feed intake (P