太湖新银鱼卵巢发育不同阶段个体生化组成和能量密度研究

CHEMICAL COMPOSITIONS AND ENERGY DENSITIES OF FEMALE NEOSALANX TAIHUENSIS WITH OVARIES AT DIFFERENT DEVELOPMENTAL STAGES

对丹江口水库太湖新银鱼雌鱼性腺发育不同阶段个体的生化组成和能量密度变化进行研究,以分析性腺发育的物质和能量来源。卵巢8—11月间基本处于Ⅱ期,之后迅速发育;1—3月主要为Ⅳ期或Ⅴ期,4月开始以Ⅵ期个体为主。卵巢发育的Ⅱ期和Ⅲ期,太湖新银鱼全鱼中的生化组成和能量密度随卵巢发育而显著增高。当发育至Ⅳ期时,全鱼和去性腺鱼体中的干物质、粗脂肪、粗灰分相对含量和能量密度仍明显增加,而粗蛋白相对含量在全鱼当中有所减少。由Ⅳ期发育到Ⅴ期时,全鱼中的各生化组成无明显变化,能量密度显著增加;去性腺鱼体中的粗蛋白相对含量显著增加,粗脂肪显著减少,其他生化组成和能量密度无明显变化。产后Ⅵ期,全鱼中的粗脂肪、粗灰分相对含量和能量密度显著下降,干物质和粗蛋白相对含量则显著上升。性腺发育成熟前(Ⅳ期前),去性腺鱼体中的总能量和粗蛋白绝对含量明显增加,而性腺中能量和粗蛋白绝对含量增加不明显,粗脂肪含量的增加明显。由Ⅳ期发育到Ⅴ期时,全鱼中的总能量、粗蛋白和粗脂肪绝对含量均略有增加,主要是由于性腺中能量、粗蛋白和粗脂肪含量的增加,而去性腺鱼体中能量、粗蛋白和粗脂肪绝对含量均明显减少。产后Ⅵ期全鱼中的总能量、粗蛋白和粗脂肪绝对含量均急剧降低。上述结果初步表明太湖新银鱼卵巢发育成熟前在鱼体中储存物质和能量,在卵巢发育成熟时这些储存的物质和能量可能向卵巢转移,成为卵巢发育成熟的主要物质和能量来源。

Chemical composition and energy density were analyzed for female Neosalanx taihuensis with ovaries at different developmental stages to determine the energy source of gonadal development. Ovaries of females were at stage Ⅱor Ⅲ from August to December, and developed quickly to stage Ⅳ or Ⅴ from January to March of the next year, then reached stage Ⅵ in April. Chemical composition and energy density in the whole fish increased significantly from stage Ⅱ to stage Ⅲ. Contents of dry matter, lipids and ash, and energy density increased significantly in the whole fish and fish both with and without ovaries from stage Ⅲ to Ⅳ, whereas relative protein content decreased in the whole fish. At mature stage （Ⅴ）, energy density in the whole fish increased, although chemical compositions did not have significant change. In fish body without ovaries, relative contents of protein increased, while lipid decreased, and chemical compositions and energy density had little changes. At the spent stage （Ⅵ）, relative contents of lipid and ash decreased in the whole fish, conversely, relative contents of dry matter and protein increased. Total energy and absolute protein content in fish body without ovaries increased from stage Ⅲ to Ⅳ, while there was little increase if ovaries were included in the analysis. Absolute lipid content in ovaries increased from stage Ⅲ to Ⅳ. At mature stage （Ⅴ）, total energy, absolute protein content, and lipid content increased slightly in the whole fish. This change primarily reflected their increases in ovaries. In the fish without ovaries, they decreased apparently. At the spent stage （Ⅵ）, total energy, absolute protein content and lipid content decreased sharply in the whole fish. Our preliminary results indicated that materials and energy were stored in fish body during the premature stages, and were then transferred to ovaries at the mature stage.