Coria María Sumampa, Reineri Pablo Sebastián, Pighin Dario, Barrionuevo Maria Guadalupe, Carranza Pedro Gabriel, Grigioni Gabriela, Palma Gustavo Adolfo
Animal Production and Reproduction Laboratory, NOA Institute of Bionanotechnology (INBIONATEC), Villa El Zanjón, Santiago del Estero, G4206XCP, Argentina.
National Council of Scientific and Technical Research (CONICET), Buenos Aires, C1033AAJ, Argentina.
Asian-Australas J Anim Sci. 2020 May;33(5):753-762. doi: 10.5713/ajas.19.0163. Epub 2019 Aug 3.
The aim of the present study was to determine the effect of supplementing pasture-finished steers with corn silage on the expression level of the calpain system proteins and beef tenderization.
Thirty Braford steers grazing on summer pasture were used for the study. For 120 days fifteen animals were supplemented with corn silage at 1% of body weight per head per day (Suppl) whereas the remaining 15 steers only received pasture (Contr). Carcass and meat traits were evaluated and compared between groups. Gene expression and activities of proteases (calpain 1 and calpain 2) and inhibitor (calpastatin) were measured using real-time polymerase chain reaction and casein zymography.
Carcass and meat traits were significantly different between feeding systems. Supplemented steers showed higher hot carcass weight (p<0.01), fat content (p = 0.02), and Warner-Bratzler shear force (p = 0.03). Furthermore, the control group showed higher protease:inhibitor ratios, at mRNA (p = 0.01) and protein levels (p<0.10). Warner-Bratzler shear force and mRNA calpains:calpastatin ratio were associated in both feeding systems (p<0.01).
Based on the results obtained in the study, beef tenderness differences among finishing strategies could be modulated through differential expression of the calpain system proteins.
本研究旨在确定用玉米青贮料补充放牧育肥牛对钙蛋白酶系统蛋白表达水平和牛肉嫩化的影响。
选用30头在夏季牧场放牧的布拉福德牛进行研究。在120天内，15头牛每天按每头体重的1%补充玉米青贮料（补充组），而其余15头牛只采食牧场草料（对照组）。对两组的胴体和肉质性状进行评估和比较。使用实时聚合酶链反应和酪蛋白酶谱法测定蛋白酶（钙蛋白酶1和钙蛋白酶2）和抑制剂（钙蛋白酶抑制蛋白）的基因表达及活性。
不同饲养系统间的胴体和肉质性状存在显著差异。补充组的牛表现出更高的热胴体重（p<0.01）、脂肪含量（p = 0.02）和沃纳-布拉茨勒剪切力（p = 0.03）。此外，对照组在mRNA（p = 0.01）和蛋白质水平（p<0.10）上显示出更高的蛋白酶与抑制剂比率。在两种饲养系统中，沃纳-布拉茨勒剪切力与mRNA钙蛋白酶和钙蛋白酶抑制蛋白的比率均相关（p<0.01）。
基于本研究获得的结果，育肥策略间牛肉嫩度的差异可通过钙蛋白酶系统蛋白的差异表达来调节。
