添加过瘤胃氨基酸低蛋白质饲粮对呼伦贝尔羊生长性能、养分表观消化率及肉品质的影响

Effects of Low Protein Diet Supplemented with Rumen-protected Amino Acids on Growth Performance,Nutrient Apparent Digestibility,Serum Biochemical and Meat Quality of Hulun Buir Sheep

旨在探究低蛋白质日粮中添加过瘤胃蛋氨酸(RPMet)和过瘤胃赖氨酸(RPLys)对呼伦贝尔羊生长性能、养分表观消化率、血清生化及肉品质的影响。选择2.5月龄断奶健康羔羊16只,编号后随机等分为2组,分别为对照组(Control group,饲喂低蛋白质日粮,粗蛋白质含量为7.84%)和试验组(Treatment group,在低蛋白质日粮基础上补充10 g·d^(-1) RPMet和15 g·d^(-1) RPLys)。预试期7 d,正试期56 d。结果显示:1)试验组的平均日采食量较对照组显著降低(P<0.05),但其平均日增高显著高于对照组(P<0.05),试验组的料重比较对照组有降低的趋势。2)两组间的屠宰性能和养分表观消化率均无显著差异(P>0.05)。3)试验组血清中的总蛋白(TP)、白蛋白(ALB)、肌酐(CREA)、乳酸脱氢酶(LDH)、谷丙转氨酶(ALT)和低密度脂蛋白(LDL)的含量显著低于对照组(P<0.05),游离脂肪酸(NEFA)含量显著高于对照组(P<0.05)。4)两组间背肌的肉色、常规营养成分、脂肪酸组成和含量无显著差异(P>0.05)。试验组肌肉中苏氨酸(Thr)含量较对照组显著升高(P<0.05),异亮氨酸(Ile)、亮氨酸(Leu)、酪氨酸(Tyr)的含量较对照组显著降低(P<0.05),试验组肌肉中风味氨基酸和必需氨基酸占总氨基酸的比例(DAA/TAA、EAA/TAA)显著高于对照组(P<0.05),必需氨基酸与非必需氨基酸的比值(EAA/NAA)显著高于对照组(P<0.05)。综上,在本试验条件下,低蛋白质饲粮中添加10 g·d^(-1) RPMet和15 g·d^(-1) RPLys对呼伦贝尔羊的生长发育有积极作用,且不会影响其养分消化率和屠宰性能,并能增加肌肉中的风味氨基酸和必需氨基酸的占比,提升羊肉的风味和营养价值。

This experiment was conducted to investigate the effects of dietary rumen-protected lysine(RPLys)and rumen-protected methionine(RPMet)supplemented in low-protein diet on growth performance,nutrient apparent digestibility,serum biochemistry and meat quality of Hulun Buir sheep.Sixteen 2.5-month-old weaned healthy lambs were randomly divided into two groups evenly:control group(fed low protein diet with crude protein content of 7.84%)and treatment group(supplemented with 10 g·d^(-1) RPMet and 15 g·d^(-1) RPLys on the basis of low protein diet).The pretrial period lasted for 7 d and the experimental period lasted for 56 d.The results showed that:1)The average daily feed intake of treatment group was significantly lower(P<0.05),but its average daily height increase was significantly higher(P<0.05),and feed to gain ratio of treatment group was lower than that of control group.2)There was no significant difference in slaughter performance or nutrient apparent digestibility between two groups(P>0.05).3)The contents of total protein(TP),albumin(ALB),creatinine(CREA),lactate dehydrogenase(LDH),alanine aminotransferase(ALT)and low density lipoprotein(LDL)in the serum of treatment group were significantly lower than those of the control group(P<0.05),and the content of free fatty acid(NEFA)was significantly higher(P<0.05)than that of the control group.4)There was no significant difference in meat color,conventional nutrients,the composition and content of fatty acid between the two groups(P>0.05).The content of threonine(Thr)in muscle of treatment group was significantly higher(P<0.05),and the contents of isoleucine(Ile),leucine(Leu),tyrosine(Tyr)were significantly lower than those of the control group(P<0.05).The proportion of delicious flavor amino acids and essential amino acids in total amino acids(DAA/TAA,EAA/TAA)in muscle of treatment group were significantly higher(P<0.05),and the ratio of essential amino acids to non-essential amino acids(EAA/NAA)was significantly higher than those of the control group(P<0.05).In conclusion,under the condition of the current experiment,adding 10 g·d^(-1) RPMet and 15 g·d^(-1) RPLys into the low protein diet has a positive effect on the growth and development of Hulun Buir sheep,and without affecting its nutrient digestibility and slaughter performance.It can also increase the proportion of delicious amino acids and essential amino acids in muscle and improve muscle quality.