Partial or total replacement of dietary fish oil with alternative lipid sources in silvery-black porgy (Sparidentex hasta)

Abstract

An eight-week feeding trial was conducted to evaluate the effects of partial (50%) or total (100%) replacement of dietary fish oil with alternative lipid sources in silvery-black porgy. Seven isonitrogenous (50%) and isolipidic (20%) experimental diets were formulated namely: FO (fish oil), CO (canola oil), SO (sunflower oil), T (tallow), FC (fish oil+canola oil, 50:50), FS (fish oil+sunflower oil, 50:50) and FT (fish oil+tallow, 50:50). Fish fed the T and FT diets statically had lower final weight, weight gain and specific growth rate than other groups (P<0.05); Fish fed FT diet had the highest feed conversion ratio (P<0.05). Fish fed the CO and SO diets had the highest and the lowest whole body and muscle protein content, respectively (P<0.05). Fillet and liver n−9 monounsaturated fatty acids, n−6 and n−3 poly unsaturated fatty acids were highest in fish fed the CO, SO and FO, respectively (P<0.05). Apparent digestibility coefficient of protein and lipid, hemolytic and bactericidal activities were lowest in fish fed the T diet (P<0.05). From the above results, it is suggested that the vegetal oil sources are recommended for total and partial replacement of FO in silvery-black porgy diets, whereas tallow is not advisable as an alternative lipid source in this species. Statements of relevanceIt is essential to introduce alternative lipid sources, to meet increasing global demands of aquafeeds for the sustainability of aquaculture industry. Thus, the aim of present study was to provide insight into the possibility of the use of alternative lipid sources in diet for silvery-black porgy juveniles by evaluating the growth performance, feed utilization, body composition and hemato-immunological parameters.