EFFECT OF D IETARY PROTEIN LEVEL ON THE GONAD DEVELOPM ENT OF FEMALE ALLOGYNOGENETI C CRUC IAN CARP

Five isocaloric diets containing 0%, 16%, 24%, 32% and 40% crude protein respectively were formulated byusing fish meal, corn starch, CM cellulose, rape oil, Ca(H2PO4)2, vitamin and mineral premixture, concomitantly, a starvation group was set to study the effect of dietary protein level on the gonad development of female Allogynogenetic cruciancarp. Fishes from the same brood stock and with an average bodyweight of (30.0±5.0) gwere randomly stocked in quadruple groups and raised in an indoor flow2through system with a light regime of 12h: 12h(8:00-20:00). The experimentlasted for 20 weeks from November to March of the next year. Sampleswere taken at the mid of each month to determinethe serum vitellogenin content and gonad somatic index. At the end of the trial, the biochemical composition ofmuscle andgonad were analyzed and the fecundity of fish and the diameter of mature eggs were measured. The results indicated thatfrom November to February, except for the serum vitellogenin content of the starvation group kept declining, the content inthe other groups increased with the rise of dietary protein level. But inMarch, because of thematuration of ovary, the serumvitellogenin content in all groups declined sharply. Although dietary protein level had no significant effect on the gonad so2matic index before January, the gonad somatic index was significantly influenced by dietary protein level in February andMarch,which increased with the rise of dietary protein level. Along with the increase of dietary protein level, the muscleand gonadπ s protein and lipid content ascended and the moisture content descended significantly. The starvation group hadthe lowest fecundity and the 40% group had the highest value, but there was no significant difference among the groups of 16%, 24% and 32%. The eggπ s diameter of the starvation group was remarkably lower than other group. The 40% grouphad the highest value which significantly higher than the starvation group and the 0% group. But thereπ s no significantdifference among the 0% to 32% group.