淡水白鲳人工繁殖的调控

REGULATION OF ARTIFICIAL REPRODUCTION IN COLOSSOMA BROCHYPOMUM

本文对控制淡水白鲳有效积温和投饲量促进性腺成熟人工诱导春繁和秋繁作了研究。春繁平均水温２３．３±１．１℃，雌、雄亲鱼有效积温分别达到３５０９．０±１６４．２和３７８６．７±８１．８度·日，平均催产率为８６．９％，比自然水温条件下，提前催产约１．５个月。秋繁平均水温２８．１±２．０℃，雌、雄亲鱼有效积温分别为２００８．８和２０３０．０度·日，平均催产率为９３．２％；秋繁千克鱼饲料量小于春繁，但千克鱼日投饲量大于春繁。产卵前后血清中１７β－Ｅ＿２和Ｔ浓度测定表明，雌鱼血清中１７β－Ｅ＿２浓度在产卵后极显著降低（春季，Ｐ＜０．０１；秋季，Ｐ＜０．００１），经秋季培育后又再升高，表明１７β－Ｅ＿２的作用主要与卵黄发生有关，但与排卵的关系不大，而睾酮在产卵过程中，雌、雄鱼均有显著升高（Ｐ＜０．００１），这与排卵、排精有关。

The regulation of effective accumulating temperature and feeding amount for promoting gonad maturation during spring and autumn induced breeding were studied. When the water temperature was 23. 3±1. 1℃, the effective accumulating temperatures were up to 3509. 0±164. 2℃ and 3786. 7 ±81.8℃ ·d. of female and male spawners respectively. The average spawning rate was 86. 9%, and the spawning time was about one and a half months early than that of the induced spawning under the condition of natural water temperature.When the water temperature was at 28. 1 ± 2.0℃, the effective accumulating temperatures were 2008. 8℃ and 2030.0℃ ·d. in female and male fish respectively, and 93. 2% spawning rate was got. The feeding amount per kilogram body weight of fish during autumn breeding was low than that of the fish during spring breeding, but higher in daily feeding amount.Serum 17β-oestradiol (17β-E2) and testosterone (T) levels were measured before and after spawning. Serum 17β-E, level showed highly significant decrease (spring, P<0. 01 and autumn, P<0. 001) in female after spawning. The serum 17β-E2 level increased when the spawned fish were recultured intensively. It suggested that the role of 17β-E2 was involved in vitellogenesis and less relationship with ovulation. The serum level of T in both female and male after spawning were highly significant increase (P<0. 001 ), and it showed in connection with ovulation and spermiation.