蛋氨酸羟基类似物钙盐缓解肉仔鸡的热应激作用

Effects of 2-hydroxy-4-(methylthio) butyrate calcium on heat stress response in broiler chickens

比较研究DL-蛋氨酸(DLM)和蛋氨酸羟基类似物钙盐(HMTBA-Ca)对肉仔鸡32℃下的抗热应激作用。252只1日龄雄性罗斯肉鸡(约49 g)随机分成6组,分别饲喂添加0.1%DLM、0.2%DLM、0.3%DLM、0.1%HMTB-Ca、0.2%HMTB-Ca、0.3%HMTB-Ca的日粮,每组3个重复。结果表明,日粮中添加0.3%HMTB-Ca的肉鸡终末体质量和平均日增质量显著高于0.3%DLM组;添加0.2%HMTB-Ca和0.3%HMTB-Ca的腿肌质量和胸肌质量显著高于相应剂量的DLM组;添加0.3%HMTB-Ca的处理组与其他5组相比全血自由基(ROS)含量显著降低;添加0.3%HMTB-Ca的处理组较0.3%DLM组肌肉、十二指肠中还原型谷胱甘肽/氧化型谷胱甘肽的比率(GSH/GSSG)显著提高,血浆、肝脏、肌肉、十二指肠、回肠中过氧化氢酶(CAT)活力显著提高;添加0.3%HMTB-Ca组较0.3%DLM组血浆和肌肉的总抗氧化能力(T-AOC)显著提高。以上结果显示,HMTB-Ca相对于DLM能够改善肉仔鸡在热应激条件下的平均日采食量、平均日增质量、料重比和胴体品质,促进肌肉生长;HMTB-Ca可在一定程度上更好地缓解氧化应激,降低机体自由基水平,保证机体氧化还原状态的平衡。

The effects of methionine （DI2~I） and 2-hydroxy-4- （methylthio） butyrate calcium （HMTBA-Ca） on the heat stress （32 ℃ ） response in broiler chickens were compared. 252 commercial broiler chickens aged 1 day were randomly assigned into 6 groups, fed on 0. 1% DLM, 0. 2% DLM, 0. 3% DLM, 0. 1% HMTB-Ca, 0. 2% HMTB-Ca, 0. 3% HMTB-Ca supplement in diets, respectively, three repeats one group. The results revealed that the final body weight and average daily weight gain of broiler chickens fed on 0. 3% HMTB-Ca diet were significantly higher than those in 0. 3% DLM group. When fed on 0. 2% HMTB-Ca or 0. 3% HMTB-Ca diet, the leg muscle weight and breast muscle weight were significantly higher than those in DLM groups at same supplemental levels. Broilers in 0. 3% HMTB-Ca group showed a significantly lower ROS（ reactive oxygen species） level in plasma compared to the other five groups. Additionally, 0. 3% HMTB-Ca supplementation caused elevated GSH/C, SSG （glutathione/oxidized glutathione） in muscle and duodenum compared to 0. 3% DLM group, as well as eatalase activities in plas- ma. liver, muscle, duodenum and ileum, and T-AOC （total antioxidant capacity）in plasma and muscle. In a conclusion, com pared with DLM, HMTBA-Ca supplement in diets could induce higher average daily feed intake, average daily gain, F/G and carcass quality. As a result, it could alleviate oxi- dant stress and reduce body free radical levels, so as to keep the balance of redox status in broiler chicken in response to heat stress.