饲粮精料水平和蛋氨酸铬添加剂量对舍饲滩羊生长性能、屠宰性能、肉品质和脂肪沉积的影响

Effects of Dietary Concentrate Level and Chromium Methionine Adding Dosage on Growth Performance,Carcass Characteristics,Meat Quality and Fat Deposition of Stabling Tan Lambs

本试验旨在探究饲粮精料水平和蛋氨酸铬(Cr-Met)添加剂量对舍饲滩羊生长性能、屠宰性能、肉品质和脂肪沉积的影响。采用2×3双因素试验设计,2个因素分别为饲粮精料水平和Cr-Met添加剂量,其中饲粮精料水平分别设为35%(低精料饲粮,饲粮精粗比为35∶65)和55%(高精料饲粮,饲粮精粗比为55∶45),Cr-Met添加剂量分别设为0、0.75和1.50 g/(d·只)。将60只雄性滩羊羔羊[平均体重为(21±1)kg]随机分配到6个试验组,每组10只。试验期为80 d,其中预试期15 d,正试期65 d。结果显示:1)与低精料饲粮组相比,高精料饲粮组滩羊的平均日增重、屠宰率、背膘厚度、肌内脂肪含量和后腿肉比重显著增加(P<0.05),但料重比与肌肉蒸煮损失、剪切力、pH、亮度(L*)值、红度(a*)值和黄度(b*)值则显著降低(P<0.05)。2)低精料饲粮组滩羊背膘厚度、皮下脂肪厚度、肌内脂肪含量和后腿肉比重随Cr-Met添加剂量的增加而线性降低(P<0.05),但肌肉pH则线性升高(P<0.05)。3)高精料饲粮组滩羊肋肉比重、腰肉比重以及肌肉剪切力和pH随Cr-Met添加剂量的增加而线性升高(P<0.05),而肌内脂肪含量和肌肉a*值则线性降低(P<0.05)。综合本试验测定指标,建议在滩羊养殖中选择精粗比为55∶45的高精料饲粮,Cr-Met的适宜添加剂量为1.50 g/(d·只),且不建议在精粗比为35∶65的低精料饲粮中添加Cr-Met。

This experiment was conducted to evaluate the effects of dietary concentrate level and chromium methionine(Cr-Met)adding dosage on the growth performance,carcass characteristics,meat quality and fat deposition of stabling Tan lambs.A 2×3 two-factor factorial design was adopted in this experiment.Factor 1 was dietary concentrate level,and it was 35%(low concentrate diet,dietary concentrate-to-forage ratio was 35∶65)and 55%(high concentrate diet,dietary concentrate-to-forage ratio was 55∶45),respectively.Factor 2 was Cr-Met adding dosage,and it was 0,0.75 and 1.50 g/(d·lamb),respectively.Sixty male Tan lambs[average body weight:(21±1)kg]were randomly assigned into 6 trial groups with 10 lambs per group.The experimental period was 80 days containing 15-day pre-experiment and 65-day formal experiment.The results showed as follows:1)compared with low concentrate diet group,the average daily gain,dressing percentage,backfat thickness,intramuscular fat content and leg proportion of lambs from the high concentrate diet group were significantly increased(P<0.05),but the feed/gain and muscle cooking loss,shear force,pH,lightness(L^*)value,redness(a^*)value and yellowness(b^*)value were significantly decreased(P<0.05).2)Lambs from the low concentrate diet group,there was a linear decrease in backfat thickness,subcutaneous fat thickness,intramuscular fat content and leg proportion(P<0.05),but a linear increase in muscle pH with increasing Cr-Met adding dosage(P<0.05).Lambs from the high concentrate diet group,the rib proportion,loin proportion and muscle shear force,and pH exhibited a linear increase(P<0.05),whereas the intramuscular fat content and muscle a^* value showed a linear decrease with increasing Cr-Met adding dosage(P<0.05).Considering all the measured indexes of this experiment,it is suggested that the optimum dietary concentrate-to-forage ratio for Tan lamp is 55∶45,the optimum Cr-Met adding dosage is 1.50 g/(d·lamb)and it is not recommended in low concentrate diet.