Effects of dietary lipid level on growth, survival and body composition of Brazilian codling (Urophycis brasiliensis Kaup, 1858)

Abstract

The aim of this study was to determine the influence of lipid level in formulated feeds on growth, survival, hepatosomatic index (HSI) and proximate composition of liver and muscle in Brazilian codling. Three different experimental diets (40% crude protein) were made using 3%, 6% and 10% of fish oil, obtaining 5%, 8% and 11% of crude lipid, respectively. Daily feeding rate was kept at 3% of fish body weight. At the end of the 40 day trial, the fish were weighed and samples from muscle and liver were taken. The highest weight gain was obtained at the lowest dietary lipid level. The lowest survival rate and greater HSI was found in the group fed with the highest lipid level. Significant differences (P<0.05) in terms of growth, survival and hepatosomatic index were observed between the groups. The group with higher lipid levels showed larger pale livers. Liver protein, lipid and water content in this group were significantly different (P<0.05) to those of fish fed the other diets. Muscle protein content was significantly lower (P<0.05) in fish fed the highest lipid level compared with the other treatments. No significant differences (P<0.05) in ash content in both organs and in lipid and water content in the muscle were found among treatments. It is concluded that the more suitable dietary lipid levels for Brazilian codling growth and survival might be around 5%.