发酵麸皮多糖对肉羊肉品质、肌肉氨基酸组成及肌肉抗氧化酶和肌纤维类型相关基因表达的影响

试验旨在研究发酵麸皮多糖(FWBP)对肉羊肉品质、肌肉氨基酸组成及肌肉抗氧化酶和肌纤维类型相关基因表达的影响。选用50只体重为(20.17±3.33)kg的6周龄杜泊×小尾寒羊F1代杂交羔羊,随机分为5组,每组10只。对照组(Ⅰ组)饲喂基础饲粮,试验组(Ⅱ、Ⅲ、Ⅳ、Ⅴ组)分别饲喂在基础饲粮中添加50、100、200、400 mg/kg FWBP的试验饲粮,预试期14 d,正试期56 d。结果表明:1)Ⅱ和Ⅲ组肉羊背最长肌剪切力显著低于Ⅰ组(P<0.05)。2)Ⅱ、Ⅲ和Ⅳ组肉羊背最长肌中蛋氨酸(Met)含量显著高于Ⅰ组(P<0.05);Ⅳ组肉羊背最长肌中的半胱氨酸(Cys)含量显著高于Ⅰ组(P<0.05),而谷氨酸(Glu)和亮氨酸(Leu)含量显著低于Ⅰ组(P<0.05);Ⅴ组肉羊背最长肌中丝氨酸(Ser)含量显著高于Ⅰ组(P<0.05),而缬氨酸(Val)含量显著低于Ⅰ组(P<0.05)。3)各试验组肉羊背最长肌中过氧化氢酶(CAT)的mRNA相对表达量显著高于Ⅰ组(P<0.05),且Ⅲ组肉羊背最长肌中CAT的mRNA相对表达量显著高于Ⅱ、Ⅳ、Ⅴ组(P<0.05)。Ⅲ组肉羊背最长肌中谷胱甘肽过氧化物酶(GSH?Px)和超氧化物歧化酶(SOD)的mRNA相对表达量显著高于Ⅰ组(P<0.05)。4)Ⅲ组肉羊背最长肌中肌球蛋白重链(MyHC)Ⅰ和MyHCⅡa的mRNA相对表达量显著高于Ⅰ组(P<0.05),且MyHCⅡx的mRNA相对表达量显著低于Ⅰ组(P<0.05)。Ⅲ、Ⅳ和Ⅴ组肉羊背最长肌中MyHCⅡb的mRNA相对表达量显著高于Ⅰ组(P<0.05)。综上所述,饲粮中添加FWBP可以降低肉羊背最长肌剪切力,改善其氨基酸组成,提高肌肉抗氧化能力,诱导Ⅱx型肌纤维向Ⅰ和Ⅱa型肌纤维的转化,且以添加100 mg/kg效果较佳。

Effects of Fermented Wheat Bran Polysaccharides on Meat Quality,Muscle Amino Acid Composition and Expression of Antioxidant Enzymes and Muscle Fiber Type-Related Genes in Muscle of Mutton Sheep

This experiment was conducted to investigate the effects of fermented wheat bran polysaccharides(FWBP)on meat quality,muscle amino acid composition and expression of antioxidant enzymes and muscle fiber type?related genes in muscle of mutton sheep.Fifty 6?week?old Dorper×thin?tailed Han crossbred lambs with an initial body weight of(20.17±3.33)kg were randomly assigned into 5 groups with 10 lambs in each group.Lambs in the control group(groupⅠ)were fed a basal diet,and others in the experimental groups(groups Ⅱ,Ⅲ,Ⅳ and Ⅴ)were fed the basal diet supplemented with 50,100,200 and 400 mg/kg FWBP,respectively.The adaptation period lasted for 14 days and the formal period lasted for 56 days..The results showed as follows:1)the longissimus dorsi shear force of mutton sheep of groups Ⅱ and Ⅲ was significantly lower than that of group Ⅰ (P<0.05).2)The content of methionine(Met)in longissimus dorsi of mutton sheep of groups Ⅱ,Ⅲ and Ⅳ was significantly higher than that of group Ⅰ (P<0.05),while the glutamic acid(Glu)and leucine(Leu)contents were significantly lower than those of groupⅠ(P<0.05);the content of serine(Ser)in longissimus dorsi of mutton sheep of group Ⅴ was significantly higher than that of group Ⅰ (P<0.05),while the valerian(Val)content was significantly lower than that of groupⅠ(P<0.05).3)The mRNA relative expression level of catalase(CAT)in longissimus dorsi of mutton sheep of experimental groups was significantly higher than that of group Ⅰ (P<0.05),and the mRNA relative expression level of CAT in longissimus dorsi of mutton sheep of experimental group Ⅲ was significantly higher than that of groups Ⅱ,Ⅳ and Ⅴ(P<0.05).The mRNA relative expression levels of glutathione peroxidase(GSH?Px)and superoxide dismutase(SOD)in longissimus dorsi of mutton sheep of group Ⅲ were higher than those of groupⅠ(P<0.05).4)The mRNA relative expression levels of myosin heavy chain(MyHC) Ⅰ and MyHC Ⅱ a in longissi?mus dorsi of mutton sheep of group Ⅲ were higher than those of group Ⅰ (P<0.05),and the MyHC Ⅱ x mR?NA relative expression level was significantly lower than that of group Ⅰ (P<0.05).The mRNA relative ex?pression level of MyHC Ⅱ b in longissimus dorsi of mutton sheep of groups Ⅲ,Ⅳ and Ⅴ was significantly higher than that of group Ⅰ (P<0.05).In conclusion,dietary FWBP supplementation can decrease the shear force in longissimus dorsi of mutton sheep,affect the amino acid composition,improve the muscle antioxidant capacity,induce the transformation of type Ⅱ b muscle fiber to typeⅠandⅡa muscle fiber,and the effect is better when FWBP supplemental level is 100 mg/kg.