中国荷斯坦牛IL8基因遗传多态性与泌乳性状以及体细胞评分的关联

Genetic polymorphism of the IL8 gene and its associations with milk traits and SCS in Chinese Holstein

以上海某奶牛场30个公牛家系的610头中国荷斯坦牛为试验材料,采用聚合酶链式反应-单链构象多态性(PCR-SSCP)技术对Interleukin-8(IL8)基因的遗传多态性进行了分析,采用混合动物模型分析了IL8基因突变位点与测定日产奶量、测定日乳脂率、测定日乳蛋白率、305d校正产奶量、305d乳脂量、305d乳蛋白量及测定日体细胞评分7个性状的相关性,寻找可用于生产实际的分子标记。共检测到KK、KA和AA3种基因型,频率分别为0.187、0.451和0.362,等位基因K和A的频率分别为0.412和0.588。该位点突变对测定日产奶量、305d乳蛋白量、305d校正产奶量和305d乳脂量以及体细胞评分影响达到极显著水平(P<0.01),对测定日乳蛋白率的影响达到显著水平(P<0.05),对测定日乳脂率影响不显著(P>0.05)。多重比较表明:KK基因型对测定日产奶量、305d校正产奶量、305d乳蛋白量和305d乳脂量极显著高于AA和KA基因型(P<0.01)。KK基因型的体细胞评分(SCS)最小二乘均值极显著低于KA、AA基因型(P<0.01)。对于测定日的乳蛋白率AA基因型显著低于KA、KK型(P<0.05)。IL8基因遗传突变对中国荷斯坦牛泌乳性状和乳房炎抗性有较大的遗传效应,可用于中国荷斯坦牛的分子标记辅助选择。

The polymorphism of Interleukin-8（IL8） gene were investigated for 610 Chinese Holstein cows of 30 bull families from a dairy farm in Shanghai using Polymerase Chain Reaction-Single Strand Conformation Polymorphism（PCR-SSCP） technique with a mixed animal model to verify the effects of the polymorphisms on some milk productive performance,tested day milk yield,tested day fat percentage,tested day milk protein percentage,305 d corrected milk yield,305 d milk fat yield,305 d milk protein yield,and somatic cell score（SCS） . The aim was to explore the significant molecular marker in practical dairy production. Three genotypes were identified and the genotypic frequencies of KK,KA,and AA were 0.187,0.451,and 0.362,respectively. The gene frequencies of K and A were 0.412 and 0.588. The results showedhighly significant（P0.01） association of IL8 mutations with tested day milk yield,305 d milk protein yield,305 d corrected milk yield and 305 d milk fat yield,SCS and tested day milk protein percentage（P0.05） . However,no association（P0.05） with tested day milk fat percentage was recorded. The cows with KK genotype had higher tested day milk yield,305 d milk protein yield,305 d corrected milk yield and 305 d milk fat yield than those with AA and KA genotypes（P0.01） . The least square mean of SCS for KK was significantly lower than that with AA and KA genotypes（P0.01） . AA genotype was significant lower in tested day milk protein percentage than KK and KA genotypes（P0.05） . The IL8 gene genetic diversity has a great genetic effect on milk traits and mastitis resistance and could be a useful genetic marker for Chinese Holstein breeding.