低蛋白氨基酸平衡日粮添加半胱胺对生长猪肉质和相关基因表达的影响

摘要

The aim of the present study was to evaluate the effects of low protein level diets with essential amino acids and cysteamine (CS) supplementation on the meat quality and related genes expression of growing pigs.A total of 120 barrows ((42.18±0.70) kg) were arranged in a 2×2 factorial arrangement in 4 treatments with 5 replicates of 6 each.The main effects were crude protein levels (16％ and 12％) and CS supplemental levels (0 and 100 mg · kg-1).The duration of the experiment was 31 days.The results showed that the low protein level diets supplemented with esscntial amino acids dccreased the shear force value (P＜0.05) and increased the intramuscular fat content of Longissimus dorsi (P＜0.05).The low protein level diets supplemented with essential amino acids increased mRNA abundance of sterol regulatory element binding protein 1c (SREBP-1c),fatty acid synthase (FAS),stearoyl-CoA desaturase (SCD) and μ-calpain in muscle (P＜0.05),decreased the mRNA abundance of hormone-sensitive lipase (HSL),carnitine palmitoyl transferase-1 (CPT-1) and calpastatin(P＜0.05).CS supplementation decreased the mRNA abundance of calpastatin(P＜0.05).No significant interaction effect between dietary protein levels and CS supplementation on the meat quality of growing pigs was observed (P＞0.05).The results indicate that low protein level diets supplemented with essential amino acids increase the intramuscular fat content and then improve meat tenderness of Longissimus dorsi in growing pigs,possibly by up-regulating lipogenic genes expression and down-regulating lipolytic genes expression;however,CS supplementation did not show any significant influence on meat quality.%旨在研究低蛋白氨基酸平衡日粮添加半胱胺对生长猪肉质和相关基因表达的影响.试验采用2×2因子试验设计,选取(42.18±0.70) kg左右的杜×长×梅阉公猪120头,随机分为4处理,每个处理5个重复,每个重复6头猪,日粮蛋白水平为16％和12％,半胱胺添加水平为0和100 mg·kg-1.试验期为31d.结果表明,低蛋白氨基酸平衡日粮显著降低了生长猪背最长肌的剪切力值(P＜0.05),显著增加了肌内脂肪的含量(P＜0.05),上调了固醇调节元件结合蛋白1c(SREBP-1c)、脂肪酸合成酶(FAS)、硬脂酰辅酶A脱氢酶(SCD)、μ-钙蛋白酶的mRNA表达量(P＜0.05),下调了激素敏感脂酶(HSL)、肉碱脂酰转移酶1(CPT-1)、钙蛋白酶抑制蛋白的mRNA表达量(P＜0.05);半胱胺的添加下调了钙蛋白酶抑制蛋白的mRNA表达量(P＜0.05).日粮蛋白水平与半胱胺添加之间不存在交互作用(P＞0.05).结果提示,低蛋白氨基酸平衡日粮可能通过上调脂质合成相关基因的表达,下调脂质降解相关基因的表达来增加肌内脂肪含量,进而改善生长猪背最长肌嫩度,半胱胺的添加对生长猪肉品质未见明显影响.