日粮添加亚麻籽对苏尼特羊肌纤维特性及肉品质的影响

Effect of Dietary Linseed Supplementation on Muscle Fiber Characteristics and Meat Quality of Sunit Sheep

目的:研究日粮中添加亚麻籽对苏尼特羊背最长肌肌纤维特性和肉品质的影响。方法:选择3月龄体质量(16.94±1.29)kg、体况良好的纯种苏尼特羊20只,随机分为2组:亚麻籽组和对照组。亚麻籽组日粮中添加8%亚麻籽,实验期3个月。结果表明:亚麻籽组羊背最长肌各类肌纤维直径均极显著低于对照组(P<0.01)、I型和IIB型肌纤维的横截面积均极显著低于对照组(P<0.01),不同类型肌纤维的数量比例、面积比例在两组之间无统计学差异(P>0.05)。亚麻籽组羊背最长肌肌球蛋白重链(myosin heavy chain,My HC)Ⅰ、My HCIIx基因表达量均极显著高于对照组(P<0.01),My HCⅡa、My HCⅡb基因表达量高于对照组(P>0.05)。亚麻籽组的琥珀酸脱氢酶活力极显著高于对照组,乳酸脱氢酶活力极显著低于对照组(P<0.01)。与对照组相比,亚麻籽组羊背最长肌pH0值显著高于对照组(P<0.05),L^*值、pH24值和剪切力极显著低于对照组(P<0.01)。两组之间的其他肉品质指标无显著性差异。结论:日粮添加亚麻籽促进了酵解型肌纤维向氧化型肌纤维转化,降低了各类型肌纤维的直径和横截面积,对改善肉的色泽和嫩度具有积极作用。

The aim of this study was to investigate the effect of dietary linseed supplementation on the histological profile of Longissimus dorsi muscle(LD)and meat quality of Sunit sheep.Methods:Totally 20 three-month-old sheep weighing(16.94±1.29)kg with good body condition were randomly divided into control and linseed groups.The linseed group was fed the control diet with 8%replacement of concentrate by linseeds and the experiment lasted for 3 months.The results indicated that the diameter of muscle fibers and the cross-sectional areas of type Ⅰ and ⅡB muscle fibers in the linseed group were significantly lower than those in the control group(P<0.01),whereas the percentage number and area of various muscle fiber types were not statistically significant between both groups(P>0.05).The linseed group demonstrated a significant increase in the relative expression of My HCⅠ and My HCⅡx genes(P<0.01)and an increase in the relative expression of My HCⅡa and My HCⅡb genes(P>0.05).Skeletal muscle from the linseed group had a statistically significant higher activity of succinate dehydrogenase(SDH)and lower activity of lactate dehydrogenase(LDH)(P<0.01).Compared with the control group,a significant increase in pH0(P<0.05)and a decrease in L^* value,pH24 and shearing force(P<0.01)were observed for The linseed group.There was no significant difference in other meat quality indicators between both groups.Conclusion:The dietary linseed supplementation has a positive effect on improving the color and tenderness of meat by promote the conversion of muscle fiber from glycolytic to oxidized,decreasing the diameter and cross-sectional areas of muscle fiber.