日粮类型及精粗比对舍饲育肥牦牛肉氨基酸和脂肪酸含量的影响

本试验旨在研究日粮精粗比对舍饲育肥牦牛肉中氨基酸含量和脂肪酸含量的影响。试验以麦洼公牦牛为研究对象,采用2×3交叉设计,日粮类型分别为玉米型日粮以及用裸大麦替代60%玉米型日粮,两种日粮由玉米和裸大麦-玉米分别与酒糟、苜蓿等混合而成,两种日粮的精料与粗料比例由低到高分别为3:7(低精料组)、4:6(中精料组)、5:5(高精料组)。试验选取36头年龄为4周岁、体重(143.98±21.01) kg、健康状况良好的麦洼公牦牛,按体重随机区组试验设计分为6个处理组,预饲期15 d,正试期180 d。试验结束后,所有牦牛全部屠宰,采集倒数第1与第2肋骨间背最长肌,测定肉样的常规营养成分、氨基酸以及脂肪酸。结果表明:日粮类型对背最长肌水分、粗蛋白(Crude protein,CP)、粗脂肪(Ether extract,EE)、粗灰分(Ash)的含量、氨基酸的组成和含量均无显著影响(p>0.05),日粮类型只对背最长肌C17:1有显著影响(p<0.05);日粮精粗比对氨基酸的组成和含量有显著影响(p<0.05),必需氨基酸占总氨基酸比例(EAA/TAA)和必需氨基酸占非必需氨基酸比例(EAA/NEAA)差异显著(p<0.05),并且随着精料比例越高,氨基酸含量越高;日粮精粗比的不同显著(p<0.05)影响了脂肪酸C18:0的含量,并且低精组和中精组的C18:0的含量显著高于高精组(p<0.05),但低精组与中精组差异不显著(p>0.05);低精组和中精组的SFA含量均显著高于高精组(p<0.05),但UFA均低于高精组(p<0.05)。低精组和中精组的UFA/SFA均显著低于高精组(p<0.05)。可见,日粮精粗比对牦牛肉的氨基酸和脂肪酸含量均具有改善作用,其中,日粮精粗比为5:5效果最好。

Effects of Diet Type and Concentrate-to-forage Ration of Diet Feed on Contents of Amino Acid and Fatty Acid of House-feeding Yak Meat

This study was conducted to investigate the effects of different levels of concentrate to forage ration of diet feed on amino acid contents and fatty acid contents of house-feeding yak meat. The Maiwa male yaks was used as research object,and the 2×3 cross-over design of experiment was adopted,the diet types were corn-type diets and 60% corn-type diets replaced with bare barley,the diet consists of corn-type concentrate and bare barley-corn-type concentrate mixed with distiller’s grains and alfalfa,respectively,the ratio of concentrate to coarse material was 3∶7(low concentrate group),4∶6(medium concentrate group),and 5∶5(high concentrate group),respectively. Thirty-six Maiwa male yaks with age of 4 years old,weighing of(143.98±21.01) kg were in good health. They were divided into 6 treatment groups according to the randomized block test design.,the pre-feeding period was 15 days,and the trial period was 180 days. At the end of the test,all calves were slaughtered and the longest muscles between the first and second ribs were collected and the conventional nutrients,amino acids and fatty acids of the meat samples were determined. The results showed that:Diet type had no significant effect on the contents of the back longest muscle moisture,crude protein,ether extract,ash contents,amino acid composition and content(p>0.05),and the diet type only had significant effect on the contents of the back longest muscle C17∶1.(p<0.05). Effect of dietary forage to concentrate a significant(p<0.05)than the composition and amino acid contents,and the ratio of essential amino acids to total amino acids(EAA/TAA)and the ratio of essential amino acids to non-essential amino acids(EAA/NEAA)were significantly different(p<0.05),and the higher the proportion of concentrate,the higher the amino acid contents. The difference in the ratio of the concentrate to the diet significantly affects the contents of fatty acid C18∶0(p<0.05),and the contents of low and medium C18∶0 was significantly higher than that of high precision group(p<0.05),but the difference between low and medium was not significant(p>0.05). The low and medium SFA levels were higher than those of the high-precision group(p<0.05),but the UFA was lower than the high-precision group(p<0.05). The values of UFA/SFA were lower and moderate than those of the high-precision group(p<0.05). Among them,the diet would have a fine ratio of 5∶5.