Nutritional programmnig of Gilthead Seabream ("Sparus aurata") during weaning for better utilization of low fish meal and fish oil diets along on-growing

Abstract

The present study examined the effect of early nutritional programming either during embryonic phase or during metamorphosis. To affect nutrient intake during these two periods either broodstock or early weaning diets were modified and their effects studied on sea bream performance, lipid metabolism, gene expression and response after a feeding challenge of the juveniles. Specific genes such as those involved in essential fatty acids metabolism, were markedly affected by the nutritional programing at both developmental windows. Far instance an up regulation of delta-6 desaturase gene expression was obtained when fish was conditioned with moderate levels of vegetable oils, whereas extreme conditioning diets inhibited the expression. Despite it was potentially possible to condition fish during metamorphosis, the larvae were very sensitive during this period and high mortalities occurred during the treatment. When fishes were programmed through broodstock nutrition, a very high survival rate was obtained. Even extreme conditioning produced reliable survival rates. After different conditioning during the embryonic period, ali fish were fed standard commercial diets far three months and, afterwards, challenged with diets containing either fishmeal and fish oil or vegetable meals and oils. Fish whose parents had been fed with higher vegetable oils showed a significantly better growth when fed with diets containing vegetable meals and oils. Thus, a significant positive effect of the nutritional programming was observed in lipid metabolism response as well as a better utilization of the feeds.