Nutritional studies in the seed production of fish - XV. Effect of nutritional composition of diets on chemical components of red sea bream broodstock and eggs produced.

Abstract

A study was conducted to obtain some basic data necessary for biochemical evaluation of egg quality by investigating a relationship between composition of diets for broodstock and chemical components of eggs produced. Both broodstock and eggs produced by broodstock, which had been fed on various diets with different nutritional quality for more than 5 months, were analysed for fatty acids, minerals, and proximate composition. There was no marked difference in proximate composition due to the difference of the nutritional quality of diets in both male and female muscles and livers except for the male broodstock fed on either the low-protein or the EFA-deficient diet where the protein content decreased and the lipid content inreased. The protein and lipid contents were higher and the water content was lower in the ovary from broodstock given the cuttlefish meal diet. Mineral composition in both broodstock tissues and eggs showed no difference, in general, even in the phosphorus content of vertebrae and eggs from the broodstock given the phosphorus-deficient diet. In the eggs produduced by the broodstock fed on the low-protein diet a slightly high moisture content and a low protein content were observed. The fatty acids in eggs were greatly affected by dietary fatty acids supplied to broodstock. The proportion of ω3 HUFA and was high in the eggs of the broodstock given the diet containing a high level of ω3 HUFA and was low in the eggs from the EFA-deficient fish, the percentage of 18:2ω6 being higher in the latter eggs due to dietary 18:2ω6 in corn oil, although a relationship between quality of eggs and their fatty acid distribution was not evident in this experiment.