Influence of varying dietary lipid levels on growth,feed conversion and chemical composition of meat and liver of the juvenile blackfin Sea Bream,Acanthopagrus berda (Forsskal 1775)

This paper reports the effects of different dietary lipid concentrations on growth,food conversion and product (meat) quality of blackfin sea bream acanthopagrus berda (mean body weight 10.2±0.5 g) juveniles which were collected from sonari channel,hawksbay,karachi and were brought to the laboratory. fish were acclimatized for 10 days. subsequently,they were placed in rectangular glass tanks (150 liters each). six fish were stocked in each tank with three replications. fish were fed four isonitrogenous (42% protein) diets of different lipid levels (15%,20%,25% and 30%) for 60 days. fish fed diet of 20% lipid showed considerable weight gain,high specific growth rate (sgr) and low feed conversion ratio (fcr) values. fish body protein concentration remained consistent though liner relationship was found between body lipid and lipid level in the diets. the hepatosomatic index (hsi) was directly proportional to the concentration of lipid in diets. generally,the nutrients like protein,lipid and ash in the fish meat were not significantly influenced by the lipid levels. no substantial changes in total quantity of saturates were noted in liver of the fish. similarly,the monounsaturated fatty acid were only partially affected. no important differences were shown in total monoenes. the over-all poly unsaturated fatty acids (pufas) were significantly increased as lipid level increased. the n-3/n-6 was found to be reduced from 5.4 to 2.3 among fish fed diets of 15% and 30% lipid levels. based on the biological data,it was estimated that optimal level of lipid for a. berda weighing from 10.2 g and 56.3 g was 20%. copyright 2015 zoological society of pakistan.