圆斑星鲽仔稚鱼色素细胞发育和体色变化

为研究圆斑星鲽早期发育过程中色素细胞的形态和分布,实验对1~72日龄的圆斑星鲽鱼苗进行了连续的显微观察,并绘制了早期发育生长曲线。结果显示,圆斑星鲽从20日龄开始进入快速的增长期,在水温12~19.5°C时完成变态发育需要50 d,黑色素细胞最早出现,数量最多,黄色素细胞次之,虹彩细胞最后发育,数量最少。变态前黑色素细胞密度先升高后降低,在9日龄密度最大为1390个/mm~2,色素细胞逐渐密集鱼体两侧对称分布;变态开始后鱼体两侧色素不对称,有眼侧体表黑色素细胞逐渐溶解消退,由成体黑色素细胞代替,体色变深,黑色素细胞密度稳定在150个/mm~2;无眼侧黑色素细胞逐渐消溶退化,体色逐渐变白。白化个体在变态开始后出现,有眼侧不能形成成体黑色素细胞,形成白化。

Early ontogeny of chromatophores and skin color changes of spotted halibut (Verasper variegatus)

The abnormity of flatfish is very common in seeding breeding in aquaculture, and the morphological characteristics and distribution of chromatophores, as well as skin color changes during early life history(0–72 d)of Verasper variegatus were continuously observed and photographed, in order to offer reference for research and practice later. Results showed that the whole period of early development of spotted halibut lasted about 50 days in spawning water at 12–19.5 ℃, and there was a rapid growing period after 20 days old.The larval melanophores occurred first and had the most contents, then xanthophores occurred, and iridophoress occurred finally. The larval cytochrome of fry body were distributed symmetrically before metamorphosis, with an increase of the melanophores density firstly and a decrease of the density followed, and the maximal density of melanophores were 1390 cells/mm2at 9 days old. When metamorphosis occurred, the cytochrome and skin color of fry became asymmetrical. On ocular side, larval melanophores of fry body disappeared and were replaced by adult ones, and skin color was saturated and black, and the density of melanophores was stable, about 150 cells/mm2 . However, on blind side, larval melanophores disappeared and no adult ones appeared, and skin color was white. In our study, albinism often occurred at metamorphosis (35 days old), and adult melanophores of ocular side were blocked, and could not pass the metamorphosis period, and became albino.