摘要
本试验旨在研究饲粮中添加烟酸对热应激肉牛屠宰性能、肉品质及脂肪代谢的影响。选取36头月龄和体重相近的锦江黄牛,随机分为3个组,每组4个重复,每个重复3头牛。适温组(TN组)和热应激组(HS组)饲喂基础饲粮,热应激+烟酸组(HN组)在基础饲粮中添加800 mg/kg烟酸。TN组采用降温系统,保证试验牛处于适温条件下;而HS组和HN组均饲养于夏季高温高湿环境。试验预试期10 d,正试期60 d。结果表明:1)HS和HN组牛舍的平均温湿指数大于79,属于中度热应激。2)与TN组相比,HS组肉牛第30、60天的血清甲状腺素(T4)含量显著降低(P<0.05),第60天的血清皮质醇(COR)含量显著提高(P<0.05);与HS组相比,HN组肉牛第30、60天的血清COR含量显著降低(P<0.05)。3)与TN组相比,HS组肉牛屠宰率显著降低(P<0.05),腹脂率和背膘厚度显著提高(P<0.05);与HS组相比,HN组肉牛的各项屠宰性能指标均无显著差异(P>0.05)。4)与TN组相比,HS组肉牛背最长肌pH45 min、pH24 h显著降低(P<0.05),背最长肌失水率和剪切力显著提高(P<0.05);与HS组相比,HN组肉牛背最长肌pH45 min、pH24 h显著提高(P<0.05),背最长肌失水率和剪切力显著降低(P<0.05)。5)与TN组相比,HS组肉牛背最长肌粗蛋白质(CP)含量显著降低(P<0.05);与HS组相比,HN组肉牛背最长CP含量有升高的趋势(P=0.057)。6)与TN相比,HS组肉牛第30天的血清甘油三酯(TG)含量有提高的趋势(P=0.060);与HS组相比,HN组肉牛第60天的血清TG含量显著降低(P<0.05)。7)与TN组相比,HS组肉牛背最长肌脂肪酸合成酶(FAS)活性显著降低(P<0.05),背最长肌激素敏感性脂肪酶(HSL)和脂蛋白脂酶(LPL)活性显著提高(P<0.05);与HS组相比,HN组肉牛背最长肌乙酰辅酶A羧化酶(ACC)活性有提高的趋势(P=0.082),背最长肌FAS活性显著提高(P<0.05)。综上所述,热应激会改变肉牛血清激素含量,降低屠宰性能和肉品质,促进脂肪分解。在饲粮中添加烟酸可以增强肉牛的抗热应激效果,降低肌肉的失水率和剪切力,提高肌肉pH,改善肉品质,并且能够调控肉牛脂肪代谢,促进脂肪沉积。
The purpose of this experiment was to investigate the effects of dietary niacin on the slaughter performance,meat quality and lipid metabolism of beef cattle under heat stress.Thirty-six healthy Jinjiang cattle with similar age and body weight were selected and randomly divided into 3 groups with 4 replicates in each group and 3 cattle in each replicate.The normal temperature group(TN group)and the heat stress group(HS group)were fed the basal diet,and the heat stress+niacin group(HN group)was fed the basal diet supplemented with 800 mg/kg niacin.The TN group adopted a cooling system to ensure that the test cattle were under suitable temperature conditions,while the HS group and the HN group were raised in a high temperature and humidity environment in summer.The pre-test period was 10 days and the experimental period was 60 days.The results showed as follows:1)the average temperature-humidity index in cowshed of the HS and HN groups was above 79,belonging to moderate heat stress.2)Compared with the TN group,the serum thyroxine(T4)content of beef cattle in the HS group was significantly decreased on days 30 and 60(P<0.05),and the serum cortisol(COR)content in the HS group was significantly increased on day 60(P<0.05);compared with the HS group,the serum COR content of beef cattle in the HN group was significantly decreased on days 30 and 60(P<0.05).3)Compared with the TN group,the carcass yield of beef cattle in the HS group was significantly decreased(P<0.05),and the abdominal percentage and backfat thickness were significantly increased(P<0.05);compared with the HS group,there was no significant difference in all slaughter performance indices of beef cattle in the HN group(P>0.05).4)Compared with the TN group,the pH45 minand pH24 hin longissimus dorsi of beef cattle in the HS group were significantly decreased(P<0.05),and the water loss rate and shear force in longissimus dorsi were significantly increased(P<0.05);compared with the HS group,the pH45 minand pH24 hin longissimus dorsi of beef cattle in the HN group were significantly increased(P<0.05),and the water loss rate and shear force in longissimus dorsi were significantly decreased(P<0.05).5)Compared with the TN group,the crude protein(CP)content in longissimus dorsi of beef cattle in the HS group was significantly decreased(P<0.05);compared with the HS group,the CP content in longissimus dorsi in the HN group tended to be increased(P=0.057).6)Compared with the TN group,the serum triglyceride(TG)content of beef cattle in the HS group tended to be increased on day 30(P=0.060);compared with the HS group,the serum TG content of beef cattle in the HN group was significantly decreased on day 60(P<0.05).7)Compared with the TN group,the fatty acid synthase(FAS)activity in longissimus dorsi of beef cattle in the HS group was significantly decreased(P<0.05),and the hormone sensitive lipase(HSL)and lipoprotein lipase(LPL)activities in longissimus dorsi were significantly increased(P<0.05);compared with the HS group,the acetyl coenzyme A carboxylase(ACC)activity in longissimus dorsi of beef cattle in the HN group tended to be increased(P=0.082),and the FAS activity in longissimus dorsi was significantly increased(P<0.05).In conclusion,heat stress can change the serum hormone content of beef cattle,reduce slaughter performance and meat quality,and promote lipid decomposition.Dietary niacin can enhance the anti-heat stress effect of beef cattle,reduce the water loss rate and shear force of the muscle,improve muscle pH,improve meat quality,regulate beef cattle lipid metabolism and promote lipid deposition.
作者
龙凡
邹必成
王丽华
瞿明仁
陈传斌
张弦
梅文亮
杨建军
许兰娇
LONG Fan;ZOU Bicheng;WANG Lihua;QU Mingren;CHEN Chuanbin;ZHANG Xian;MEI Wenliang;YANG Jianjun;XU Lanjiao(Engineering Research Center of Nutritional Feed Development,Jiangxi Province Key Laboratory of Animal Nutrition,College of Animal Science and Technology,Jiangxi Agricultural University,Nanchang 330045,China;Jiangxi Medical Device Testing Center,Nanchang 330029,China;Gaoan Yufeng Agriculture and Animal Husbandry Limited Company,Yichun 330800,China)
出处
《动物营养学报》
CAS
CSCD
北大核心
2023年第2期941-952,共12页
CHINESE JOURNAL OF ANIMAL NUTRITION
基金
江西省自然科学基金面上项目(20192BAB204020)
国家肉牛牦牛产业技术体系(CARS-37)
国家自然科学基金项目(32060760)。
关键词
烟酸
热应激
肉牛
屠宰性能
肉品质
脂肪代谢
niacin
heat stress
beef cattle
slaughter performance
meat quality
lipid metabolism
