Simulation of Population Regulation in Lake Whitefish Coregonus Clupeaformis

Abstract

本試驗以高度不飽和脂肪酸不同量的飼料飼養黑鯛種魚，以探討高度不飽和脂肪酸對產卵及卵質的影響。試驗為種魚餵飼4種飼料約3個半月後，連續產卵了約2個月。種魚餵以魚粉為主蛋白源分別添加0、4、12％魚油的飼料，其平均每公斤產卵量分別為67.9、248.2及146.8×10^(4)粒卵，而浮卵率則為69、73.8及66.9％。餵以酪蛋白為主蛋白源且僅添加玉米油的種魚之產卵量及浮卵率為四組試料中最低的，其値分別為45.37×10^(4)粒卵及58.1％。此顯示黑鯛種魚飼料若以魚粉為主蛋白源添加4％魚油（或含2.79％HUFA於飼料中）即可達到良好的效果。分析浮性卵之脂質結果顯示，浮性卵中的極性與非極性脂質含量及其脂肪酸組成與產卵期及卵質無關，其浮性卵脂質的脂肪酸組成可反應飼料中脂肪酸組成，且在所有脂肪酸中，以18:2n6及20:5n 3最明顯，而22:6n 3之百分組成在極性脂中較穩定，且與其在飼料中含量的關係亦不明顯。A feeding experiment was conducted to determine the effect of highly unsaturatedfatty acids(HUFA)level in broodstock diet on spawning and eggquality of black porgy.After broodstocks were fed four test diets for aboutthree and half months,they spawned for about two months continually.Theeggs produced/kg/fish and percentage of buoyant eggs of broodstocks fed dietswith fish meal as main protein source and supplemented with 0,4 and 12% fishoil were 67.9,248.2 and 146.8×10^(4) eggs,and 69,73.8 and 66.9%,respectively.Theeggs produced/kg/fish and percentage of buoyant eggs of broodstocks feddiet with casein as main protein source and supplemented only with corn oilwere the lowest among the four test diets,with the value of 45.2×10^(4)eggs and58.1% respectively suggesting that 4% of fish oil(or 2.79% HUFA in diet)supplementation would improve the spawning and egg quality of black porgyif fish meal was the main protein source in the broodstock diet.Polar andnonpolar lipid contents and fatty acid composition of buoyant eggs were independentto the egg quality and spawning period.Fatty acid compostion ofdiets reflected to that of buoyant eggs,and 18:2n6 and 20:n5 were the mostdistinguish among all the fatty acids.The percentage of 22:6n3 tended to keepconstant in polar lipids and did not reflect the amount in diet to buoyant eggs.