中华绒螯蟹“长荡湖1号”新品系选育第二代(G2)生长、性腺发育和养殖性能的研究

EVALUATION ON GROWTH,GONADAL DEVELOPMENT,AND CULTURE PERFORMANCE OF“CHANGDANG LAKE 1”NEW STAIN OF SECOND-GENERATION OF CHINESE MITTEN CRAB(ERIOCHEIR SINENSIS)

“长荡湖1号”A系和B系是分别以成活率和大规格为主要选育指标建立的两个相互独立的中华绒螯蟹(Eriocheir sinensis)选育品系,为评估“长荡湖1号”偶数年群体(偶数年繁殖孵化)选育第二代(G2)的选育效果,本实验以未选育群体作为对照组,比较了两选育品系和对照组在实际池塘养殖条件下的生长、性腺发育和养殖性能。结果显示:(1)两选育品系A系和B系在扣蟹、成蟹养殖阶段的最终平均体质量均高于对照组,其中B系雌体与对照组具有显著差异(P<0.05);无论雌体还是雄体,B系最终平均体质量均略高于A系,但无显著差异(P>0.05);(2)各组实验蟹雌雄个体在成蟹阶段的生殖蜕壳高峰期分别为2021年8月10~30日和8月30日~9月20日,各组成蟹完成生殖蜕壳后性腺迅速发育,并且性腺发育后期,对照组GSI最高、B系的GSI最低;(3)就成活率而言,三组蟹在扣蟹和成蟹阶段的成活率大小顺序为:A系>对照组>B系,差异不显著(P>0.05);而在产量、大规格蟹比例和饲料系数方面,两选育品系均优于对照组。综上,经过两代配套系选育,“长荡湖1号”A系和B系均获得良好的选育进展,其中A系具有高成活率和高产量的特点,B系具有平均体质量大、大规格成蟹比例高和饲料系数低等优势。

The“Changdang Lake 1”Strains A and B of Chinese mitten crab(Eriocheir sinensis)were selected in terms of the economic indices of survival and growth performance,respectively.The growth,gonadal development,and culture performance of the second-generation(G2)of the“Changdang Lake 1”were evaluated in comparison with the control.Results show that the average body weight of two selected strains were greater than that of the control in the juvenile and adult culture stages,and the final body weight of females in Strain B was significantly greater than the control(P<0.05).In addition,the average body weight of crabs in Strain B was always higher than Strain A during the culture experiments with no significant difference(P>0.05).The puberty molting of female and male in all groups concentrated on Aug.10~30 and Aug.30~Sep.20,respectively.The gonadal development initiated soon after completing the puberty molting.In late gonad development,the maximum gonadosomatic index(GSI)occurred in the control group and the minimum in Strain B group.The survival rate of Strain A in the juvenile and adult stages was 6.77%and 7.76%higher than the control group,respectively,but the survival rate of Strain B was slightly smaller than the control.The final yield and the percentage of large-sized individuals in the two strains were greater than that of the control,while the feed conversion rate(FCR)was relatively smaller in the two selected strains.Therefore,the two crab strains achieved expected economic values after two generations of selection,of which Strain A showed greater survival rate and yield,and Strain B presented more large-sized individuals,larger adult size,and lower FCR.