CAST基因型与营养水平互作对猪胴体性状的影响研究

钙蛋白酶抑制蛋白CAST (Calpastatin)对肌内蛋白降解、肌细胞生长速度以及屠宰后钙蛋白酶的活性具有重要的影响，研究CAST基因多态性的遗传效应及其与营养水平的互作影响对猪胴体品质的控制具有重要的作用。本试验使用杜洛克和大围子2个纯种猪群，杜洛克×（长白×大白）和大白×大围子2个杂种猪群，利用HinfⅠ, MspⅠ和RsaⅠ3种内切酶研究了CAST基因的RFLP及其与营养水平互作对猪胴体性状的影响。结果表明，HinfⅠ、MspⅠ和RsaⅠ3种内切酶在4个猪群均获得RFLP，酶切位点分别存在一对等位基因A与B， C与D及E与F。AA型×高营养水平互作显著降低熟肉率和滴水损失，但与中水平互作却显著提高滴水损失（P<0.05）。AB型×高营养水平互作显著降低胴体长和眼肌面积，提高肌肉的滴水损失；但AB型×中营养水平互作则显著降低屠宰率、背膘厚和熟肉率，并提高腿臀比例和瘦肉率（P<0.05）。CD型×高水平互作对所有性状的互作效应显著，CC型×中营养水平组提高滴水损失（P<0.05）。EF型×高营养水平互作能对多个性状产生达到或超过群体均数的10%的效应（P<0.05），EE型×中营养水平互作显著增加背膘厚。

Interaction Effects of Calpastatian (CAST) Genotype and Nutrition Levels on Pig Carcass Traits

CAST gene plays an important role in muscular protein degradation, muscle cell proliferation and post-slaughter calpain activation. Study on interaction effects of polymorphisms of CAST gene and nutrition levels has an essential role in the regulation of pig carcass quality. Interaction effects of polymorphisms of CAST gene at HinfⅠ, MspⅠand RsaⅠsites and three nutrition levels on meat carcass traits were studied among four pig population including Duorc, Daweizi, Durocⅹ(LandraceⅹLarge White) and Larege White ⅹDaweizi. The results showed that the three RFLP markers of gene CAST were all polymorphic in the four pig populations. These RFLPs are bi-allelic, with alleles A and B at HinfI, alleles C and D at MspI, and alleles E and F at RsaI. Genotype AA was significantly associated with reduced cooking percentage and drop loss in the high nutrition group, and with augmented drop loss in the moderate nutrition group (P<0.05). Genotype AB was associated with significantly decreased carcass length and loin eye area, and with increased drop loss in the high nutrition group, and with significantly decreased dressing percentage, back-fat thickness, and cooking percentage in the moderate nutrition group. Genotype CD showed significant interaction with high nutrition level on all traits. Genotype CC significantly increased drop loss (P<0.05). The performance of pigs of genotype EF overcame the average by 10% in some traits, when fed with high nutrition diets (P<0.05). The interaction between genotype EE and moderate nutrition level was significant on back-fat thickness.