ScholarWorks@중앙대학교

초록

This study aimed to investigate the effect of dietary glycine (Gly) and betaine (Bet) on productive performance, egg quality, liver health, intestinal characteristics, and stress response in aged laying hens under heat stress (HS) conditions. A total of 384 aged laying hens were allotted to 1 of 4 dietary treatments in a completely randomized design with a 2 &#xd7; 2 factorial arrangement, including 2 supplemental levels of Gly (0 and 0.65%) and Bet (0 and 0.20%) in diets. Each treatment had 8 replicates. All hens were exposed to a cyclic HS condition at 31.7 &#xb1; 1.7&#xb0;C for 8 hour/day and 27.2 &#xb1; 1.3&#xb0;C for the remaining time during a 12-week feeding trial. No main and interactive effects of dietary Gly and Bet supplementation were identified for productive performance and egg quality in aged laying hens under HS conditions. However, for the main effects, Gly supplementation decreased liver color score (p < 0.01) and malondialdehyde (MDA) levels (p < 0.05), while Bet supplementation also decreased liver MDA levels (p <&#x202f;0.05). An improvement in intestinal barrier function (p <&#x202f;0.01) and a decrease in feather corticosterone concentrations (p &#x202f;<&#x202f;0.01) were observed by individual and combined supplementation of Gly and Bet. However, combined supplementation of Gly and Bet showed no synergistic benefits over individual supplementation. Dietary supplementation of 0.65% Gly and 0.20% Bet improved liver health, intestinal barrier function, and reduced stress responses in aged laying hens under HS conditions with little interactive effects of their combined supplementation.

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