Authors
1
Department of Fisheries, Faculty of Marine Natural Resources, Khorramshahr University of Marine Science and Technology, Khorramshahr, Khouzestan, Iran.
2
South Iran Aquaculture Research Institute, Iranian Fisheries Science Institute (IFSRI), Agricultural Research Education and Extension Organization (AREEO), Ahwaz, Iran
3
Department of Pathobiology, Faculty of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran
10.22092/ijfs.2025.134846
Abstract
A six-week investigation was conducted to examine the interactive influences of dietary lipid sources and soybean lecithin (SBL) levels on some physiological responses of Asian seabass (Lates calcarifer) juveniles (50.2±2.3 g). A research design containing three SL levels, including 0, 2 and 4%, and four lipid sources, including fish oil (FO), vegetable oils (VO, canola and soybean oils; 1:1), rendered animal fats (RAF, lamb and poultry oil; 1:1), and their mixture (MIX) (FO, VO, and RAF; 1:1:1). Based on this twelve experimental groups were designed as follow, 1) FO (FO without SBL), 2) FO+2 (FO+2% SBL), 3) FO+4 (FO+4% SBL), 4) VO (VO without SBL), 5) VO+2 (VO+2% SBL), 6) VO+4 (VO+4% SBL), 7) RAF (RAF without SBL), 8) RAF+2 (RAF+2% SBL), 9) RAF+4 (RAF+4% SL), 10) MIX (MIX without SBL), 11) MIX+2 (MIX+2% SBL) and 12) MIX+4 (MIX+4% SBL). Asian seabass juveniles were distributed into thirty-six 300-L container (15 fish in each replicate) filled with 220 L of sea water (45.0±0.5 g/L). The experimental diets were offered to fish three times daily (27.1±1.2°C). The lowest final weight was in VO group and the highest growth performance were in FO+2, RAF+2, RAF+4, MIX +2 and MIX+4 groups (p<0.05). In addition, feed intake (FI) and feed conversion ratio (FCR) ratio decreased in fish fed VO diet, but SL supplementation increased FI and FCR values (p<0.05). The amounts of n-3 / n-6 polyunsaturated fatty acids (PUFA) ratio, long chain-PUFA in fish fed diets containing FO increased. Plasma total protein and globulin in fish fed FO, VO+2 and RAF+4 were higher than those fed VO and RAF+2 diets. The highest and lowest plasma alternative complement activities were in FO+2 and VO groups, respectively (p<0.05). The fish fed with VO and RAF+2 diets had the highest and lowest plasma triglycerides levels, respectively. The highest and lowest plasma cholesterol were in RAF and FO+4, respectively. The findings of this investigation showed that dietary FO replacement with mixture of various lipid sources and SBL supplementation at 2% can improve growth, fatty acid profile and humoral immune responses in L. calcarifer juveniles.
Keywords
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