Effect of dietary protein and lipid levels on Growth, Body composition and biological and reproductive performances of adult Yellow fin sea bream , Acanthopagrus latus

A study was conducted to determine the effects of dietary protein and lipid levels on growth, feed utilization and reproductive performance and biochemical composition of Acanthopagrus latus broodstock. Nine diets representing a combination of three protein levels (40, 50 and 60%) and three lipid levels (15, 20 and 25%) were tested with three replicates in 1140 L cylindrical tanks. Each replicate was stocked with 10 fish with a sex ratio of 1:1 and the average weights were 415g and 236g for females and males respectively. Fish were fed to satiation, twice daily. The growth of females was not significantly affected (P >0.05) protein and lipid levels but growth of males was significantly affected (P<0.05) by dietary protein and lipid levels. Except of protein and lipid efficiency ratios, feed utilization performances of A. latus broodstock was significantly influenced by dietary protein and lipid levels. Reproductive performances of A. latus broodstock was significantly affected by dietary protein and lipid levels, except of buoyant eggs and fertilization rate percentages. Egg dimension, hatchling and 3 day-old larvae were significantly (P<0.05) affected by dietary protein and lipid levels. Body crude protein and lipid concentration were significantly (P<0.05) affected by dietary protein and lipid levels. Protein and lipid concentration of newly hatch and 3 daypost hatching larvae varied significantly (P<0.05), whereas only the crude lipid content of the egg varied significantly (P<0.05) with the change of dietary protein and lipid levels. The ratio essential amino acid to non-essential amino acid of carcass, egg, newly hatched and 3 days post hatching larvae were significantly influenced by dietary protein and lipid levels. Fatty acid profile of carcass, liver, egg, hatchling and 3 days post hatching larvae was generally affected by dietary protein and lipid levels. The present study revealed that the best biological and reproductive performance of Acanthopagrus latus broodstock could be achieved at 60% dietary protein and 20% dietary lipid concentration.

Iranian Fisheries Science Research Institute

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