饲粮甘草茎叶水平对阿勒泰羊羊肉风味的影响

Effects of Glycyrrihizic Stem and Leaf Supplemental Levels on Mutton Flavor of Altay Mutton Sheep

旨在研究饲粮甘草茎叶水平对育肥期阿勒泰羊羊肉肌酐酸、硫胺素、胆固醇、脂肪酸和氨基酸的影响,探讨育肥期阿勒泰羊饲粮中甘草茎叶的适宜添加水平。选取体质量为40 kg的6月龄健康阿勒泰羊60只,随机分为6组,每组10只羊。分别饲喂6种甘草茎叶添加水平不同的等能等氮试验饲粮(对照组Ⅰ组甘草茎叶添加水平为0.00%,试验组Ⅱ、Ⅲ、Ⅳ、Ⅴ、Ⅵ组甘草茎叶添加水平分别为10.01%、14.95%、20.41%、29.98%、60.11%)。试验期为60 d。结果表明:除了Ⅵ组羊肉背最长肌中硫胺素质量分数显著低于对照组(P<0.05)外,其他各组与对照组差异不显著(P>0.05)。虽然不同甘草茎叶添加水平对背最长肌中肌苷酸和胆固醇的质量分数影响不显著(P>0.05),但Ⅳ组肌苷酸质量分数最高,比对照组提高了20.67%,而胆固醇质量分数最低,比对照组降低了45.33%。与对照组比较,Ⅲ组背最长肌中二十碳二烯酸的质量分数极显著降低(P<0.01),二十一碳烯酸和二十二烷酸的质量分数显著降低(P<0.05),其他各组差异均不显著(P>0.05);从背最长肌中主要的饱和脂肪酸硬脂酸来看,Ⅳ组降低程度最大,降低了10.55%;从主要的不饱和脂肪酸油酸来看,Ⅲ组增加幅度最大,增加了5.54%;而从必需脂肪酸亚麻酸来看,仅有Ⅳ组有所增加;Ⅴ组的总饱和脂肪酸质量分数低于其他各组,而总不饱和脂肪酸质量分数高于其他各组。与对照组比较,Ⅵ组极显著降低了背最长肌中蛋氨酸质量分数(P<0.01),Ⅲ组显著降低了背最长肌中酪氨酸质量分数(P<0.05);而Ⅳ组背最长肌中丝氨酸、丙氨酸、缬氨酸、异亮氨酸、亮氨酸、天冬氨酸和氨基酸总量均显著高于Ⅵ组(P<0.05),但与对照组及其他甘草茎叶添加组间并无显著差异(P>0.05),此外,Ⅳ组背最长肌中谷氨酸、天冬氨酸和丙氨酸的质量分数均高于其他各组。由此可见,Ⅳ组有利于改善羊肉背最长肌中肌苷酸、胆固醇、风味氨基酸和人体必需脂肪酸的质量分数;Ⅳ和Ⅴ组有助于提高羊肉背最长肌中不饱和脂肪酸和必需脂肪酸的质量分数;综合考虑,20.41%甘草茎叶添加水平最佳,29.98%甘草茎叶添加水平次之。

This study is to investigate the effects of glycyrrihizic stem and leaf supplemental levels on creatinine,thiamine,cholesterol,fatty acids and amino acids in Altay mutton sheep,to explore the suitable glycyrrihizic stem and leaf supplemental levels for fattening period of Altay sheep.60 Altay mutton sheep with the age of 6 months and an average body weight of(40±2.5)kg were randomly assigned to 6 groups with 10 sheep each group.Sheep in groupⅠ(control group)were fed a basal diet,while the sheep in groupⅡtoⅥ(experimental groups)were fed with experimental diets supplemented with 10.01%,14.95%,20.41%,29.98%,60.11%glycyrrihizic stem and leaf on the basis of the basal diet,respectively.The experimental period was 60 days.The results showed that the thiamine quality fraction in longissimus dorsi of altay sheep of groupⅥwas significantly lower than that of control group(P<0.05),there were no significant differences between other experimental groups and control group(P>0.05).Though glycyrrihizic stem and leaf supplemental levels had no significant influences on inosinic acid and cholesterol quality fraction in longissimus dorsi(P>0.05),inosinic acid quality fraction in groupⅣwas the highest,and 20.67%higher than that of control group,and cholesterol quality fraction in groupⅣwas the lowest and 45.33%lower than that of control group.Compared with control group,eicosendioic acid quality fraction in longissimus dorsi in groupⅢdecreased significantly(P<0.01),docosahexaenoic acid and docosanoic acid quality fraction decreased significantly(P<0.01).While there were no significant differences among other experimental groups(P>0.05).From the view of stearic acid,the main saturated fatty acid in longissimus dorsi,the degree that decreased in groupⅣwas the largest and reduced by 10.55%.Decision from oleic acid,the main unsaturated fatty acid,the extent of increase in groupⅢwas the largest and increased by 5.54%.From the view of linolenic acid,the essential fatty acid,which increased only in groupⅣ.The quality fraction of total unsaturated fatty acid in groupⅤwas lower than other groups and the quality fraction of total unsaturated fatty acid was higher than other groups.The methionine levels in longissimus dorsi of groupⅥdecreased significantly(P<0.01).Tyrosine levels in longissimus dorsi of groupⅢdecreased significantly(P<0.05).Serine,alanine,valine,isoleucine,leucine,aspartic acid and total amino acids of longissimus dorsi in groupⅣwere significantly higher than that of groupⅥ(P<0.05),while there were no significant differences among control group and other experimental groups(P>0.05).In addition,the quality fraction of glutamic acid,aspartic acid and alanine of longissimus dorsi in groupⅣwere higher than other groups.It is concluded that groupⅣis helpful to improve the levels of inosine acid,cholesterol,flavor amino acids and essential fatty acids in longissimus dorsi.GroupⅣandⅤare helpful to improve the quality fraction of unsaturated fatty acids and essential fatty acids in longissimus dorsi.Comprehensively,20.41%glycyrrihizic stem and leaf supplemental level is best,29.98%glycyrrihizic stem and leaf supplemental level is next to it.