近交对凡纳滨对虾(Litopenaeus vannamei)生长、存活及抗逆性的影响

通过设计交配组合,建立中度近交组GM(近交系数大于0.25,家系G1,G2,G3,G4)、轻度近交组GL(近交系数0.0625—0.25,家系Z1,Z2,Z3,Z4),非近交组GN(近交系数为0,家系F1,F2,F3,F4),比较共同环境养殖90d不同近交程度凡纳滨对虾(Litopenaeus vannamei)家系体质量(BW)、存活率(SR)、高氨氮耐受存活率(SRA)及低溶氧耐受存活率间(SRH)的差异性,计算近交家系相关性状的近交衰退系数,评价近交对凡纳滨对虾生长、存活和抗逆性的影响。结果显示:GN组BW为7.66±2.86g,显著高于GM组BW(P0.05);GL组SR、SRA、SRH间差异近交衰退系数为–6.41%、–13.63%、–11.84%;GM组的SR、SRA、SRH的近交衰退系数为5.30%、–4.73%、–4.77%;Z2的BW最大为8.59±3.85g,G3的BW高于GN组均值;G2家系SR为84.81%±10.37%,显著高于其它家系(P0.05);75%的近交家系表现出SR近交衰退,62.5%的近交家系表现出SRH近交衰退。结果表明:近交导致凡纳滨对虾生长、高氨氮耐受性及低溶氧耐受性的衰退普遍存在,应避免高度近交个体的产生,近交系数应控制在0.25以下;少数近交家系的生长、存活、高氨氮耐受性或低溶氧耐受性优于非近交家系,推测选择合理亲缘选配方案可加快凡纳滨对虾遗传改良进程。

EFFECTS OF INBREEDING ON GROWTH, SURVIVAL AND STRESS RESISTANCE IN LITOPENAEUS VANNAMEI

We conducted a comparative study on body weight (BW),survival rates in 96 h under high-concentration ammonia (SR_A) or hypoxia (SR_H) for Litopenaeus vannamei families of different inbreeding degrees.The study was performed in a normal environment for 90 d.Three groups each having four families were set up in terms of inbreeding degree,i.e.,the group of moderate inbreeding degree (G_M) whose inbreeding coefficients (IC) were >0.25,that of light degree (G_L)(IC between 0.0625 and 0.250),and that of zero degree (G_N)(an outbred group,IC at 0).In addition,the inbreeding depression coefficient was calculated.The results show that the BW of G_N was 7.66±2.86g,which was significantly higher than that of G_M.The difference between SR,SR_A,and SR_H of G_L and G_N were not significant.The inbreeding depression coefficient of SR,SR_A,and SR_H of G_L were -2.05%,-1.35% and -1.07%,while those of G_N were 0.93%,-0.89% and -0.76%,respectively.The maximum BW occurred in G_L for 8.59±3.85g.The maximum SR was in G_M for 84.81%±10.37%,which is well above the others''.Of all the inbred families,75% presented inbreeding depression in SR_A,and 62.5% in SR_H.In other words,inbreeding depression was a common consequence for L.vannamei in growth performance and tolerance to high-concentration ammonia or hypoxia.Therefore,highly-inbred individuals should be avoid and the IC should be selected below 0.25.However,few inbred individuals showed better performance in growth and tolerance against high-concentration ammonia or hypoxia.Above all,by selecting an appropriate mating strategy,the shrimp breeding could be improved and benefited.