银鲫不同雌核发育系的生物学特性比较研究
A COMPARATIVE STUDY OF THE BIOLOGICAL CHARACTERS OF GYNOGENETIC CLONES OF SILVER CRUCIAN CARP (CARASSIUS AURATUS GIBELIO)
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摘要: 银鲫不同雌核发育系间,以D系银鲫体型最高,其相对体高平均为47%,A系为44.4%,C系为43.7%,B系为41.7%。在生长速度方面以D系生长最快,其次为A系,这两个系的银鲫在含肉量与肌肉蛋白质含量上均无明显差异,但D系银鲫对饵料的利用效率明显高于A系,因此生产上养殖以D系银鲫为母本,红鲤为父本人工繁殖而成的高体型异育银鲫,可提高经济效益10—20%。银鲫4个雌核发育系的卵巢发育进程不同,D系卵母细胞在2月份有个迅速发育期,因而最早进入成熟产卵期。A系成熟产卵期略晚,C系成熟产卵期较迟。银鲫染色体数目存在系间差异,D系染色体数目为162,A系和C系为156。Abstract: This paper describes a comparative study of the biological characters of four gynogenetic clones, A, B, C and D of silver crucian carp. Clone D hnas the greatest body depth, With a relative body depth (body depth/body length×100%)of about 47%. The relative body depth in clone A, B and C is 44.4%, 41.7% and 43.7% respectively. Clone D exhibits the highest growth rate, its growth rate is 14.7% higher than that of clone A, which has the second highest growth rate. Results from the present study and the experiments in 1987 indicated that the growth rate in the four clones were in the order clone DACB, and growth rates in their allogynogenetic offsprings were in the order clone D≥ACB. There was not significant difference on the muscle content or the protein content of the muscle among the clones. Apparently, clone D was able to utilize the food with a higher efficiency than clone A. It was estimated that use of allogynogenetic crucian carp from clone D for culture world increase the economic value by 10—20%. Ovary development was different in the four gynogenetic clones. Clone D showed a phase of rapid oocyte development in February and entered ovary maturation in mid—March. Clone A entered ovary maturation between the end of March and the begining of April, and clone C between mid—April and the begining of May. The crucian carp spawn several times in a spawning season. The fish of clone D, after the first spawning, can spawn for the second time after a period of culture in ponds. Inter—clone difference also existed in the number of chromosomes. The number of chromosome is 162 in clone D and 156 in clone A and C.