Lipid content and fatty acid composition in wild-caught silver pomfret ( Pampus argenteus) broodstocks: Effects on gonad development

Abstract

The fatty acid reserves of broodstocks profoundly affect the fecundity of spawners as well as the quality of the newly hatched larvae. Investigation of the lipid and fatty acid changes in wild-caught broodstocks during the reproductive season should elucidate the most effective strategy with which to enrich broodstocks in artificial breeding programs. This paper investigated the lipid and fatty acid compositions of wild broodstocks of silver pomfret, Pampus argenteus, caught at the Zhoushan fishery ground during the reproductive season. The results indicated that there were significant differences in lipid content among gonad, muscle and liver; mean lipid levels in ovary, testis, liver and muscle were 41.85%, 18.54%, 27.80% and 32.31%, respectively. The lipid content in gonads at developmental stages III–V was relatively more stable than that in muscle or liver, although the lipid level increased in ovary and decreased in muscle as the female broodstocks developed from phase III to phase V. There were significant differences in fatty acid levels among broodstock ovary, testis, muscle and liver. The dominant fatty acids in ovary were as follows: 18:1n−9 (16.91%) > DHA (docosahexaenoic acid) (15.46%) > 16:4n−3 (13.14%) > 16:0 (12.65%) > EPA (eicosapentaenoic acid) (6.46%) > 16:1 (5.34%). In female broodstock liver and muscle, the dominant fatty acids were 16:0 (36.42%) > 18:1n−9 (23.26%) > 18:0 (7.50%) > 16:1 (6.98%) > 14:0 (5.10%) > DHA (4.98%) and 18:1n−9 (26.35%) > 16:0 (24.07%) > DHA (8.38%) > 16:1 (6.62%) > 18:0 (5.48%) > 14:0(4.44%), respectively. The dominant fatty acids in testis were as follows: DHA (29.84%) > 16:0 (23.93%) > 18:1n−9 (8.78%) > 18:0 (7.98%) > EPA (7.96%) > ARA (arachidonic acid) (3.24%). In the liver and muscle of male broodstocks, the dominant fatty acids were 16:0 (30.14%) > 18:1n−9 (25.54%) > 18:0 (8.24%) > 16:1 (7.24%) > 14:0 (5.20%) > DHA (4.75%) and 18:1n−9 (29.51%) > 16:0 (23.90%) > DHA (7.80%) > 18:0 (6.34%) > 16:1 (6.22%) > 14:0(3.88%), respectively. The n−3PUFAs and n−3/n−6 ratios in ovary and testis of the broodstocks were significant higher than those in the liver and muscle of the broodstocks. The changes in fatty acid composition in ovary and testis as the broodstocks developed from phase III to phase V were smaller in magnitude than those in muscle or liver. It is therefore suggested that the lipid preferentially transferred to ovary from muscle during the reproductive season, and the PUFAs, such as DHA, EPA, 16:4n−3 and ARA, were selectively transferred to, and conserved in, the ovaries of silver pomfret broodstocks.