太平洋鳕性腺发育及营养来源的初步研究

The gonad development and nutrition source of Pacific cod Gadus macrocephalus

通过对大连海域太平洋鳕Gadus macrocephalus的繁殖力、卵径分布、性腺指数(GSI)和肝指数(HSI)进行周年调查,确定出太平洋鳕的繁殖期,分别测定了不同发育期太平洋鳕性腺、肝脏和肌肉的生化组成、能量密度变化,并观察了不同发育期太平洋鳕性腺和肝脏的组织学变化。结果表明:大连海域太平洋鳕的卵巢从12月开始进入第Ⅳ期,至翌年2月份排放;精巢处于Ⅳ、Ⅴ期的时间较长,11月份就有达到成熟的个体;从太平洋鳕肝脏组织学的变化来看,脂滴的体积变化很大,说明在繁殖过程中,肝脏经历了一个脂肪先积累又被大量消耗的过程;太平洋鳕在繁殖过程中,各个组织的能量密度变化较小,但粗蛋白、粗脂肪、粗灰分等成分变化较大。研究表明,太平洋鳕性腺发育的脂肪主要可能来源于肝脏,而肌肉蛋白的下降可能充当了性腺发育中蛋白质的主要来源。

Fecundity,egg diameter frequency distribution,gonosomatic index（GSI） and hepatosomatic index（HIS） of Pacific cod Gadus macrocephalus in Dalian sea area were investigated yearly in this study.Changes in chemical compositions,energy density and histology of gonad,liver and muscle of Pacific cod were observed and measured in different stages.The ovary of Pacific cod was in Ⅳ stage from December and ovulated in February in the next year.The spermary lasted a long time in Ⅳ and V stages,and with sperm present from November.According to the histological changes in the liver,oil drops were found to be changed a lot,indicating that liver underwent a process of lipid accumulated and consumed in breeding process.The energy in each tissue was less influenced in the breeding process,which were the conditions of basic living need.However,protein,fat and ash were changed a lot,which associated with breeding.The results showed that the main lipid source for the gonad development of Pacific cod might come from liver.The main protein source for the gonad development of Pacific cod is suggested to come from muscle.