Abdel-Ghany Heba M, Salem Mohamed El-S, Ezzat Altaf A, Essa Mohamed A, Helal Amr M, Ismail Rania F, El-Sayed Abdel-Fattah M
National Institute of Oceanography and Fisheries, NIOF, Cairo, Egypt.
National Institute of Oceanography and Fisheries, NIOF, Cairo, Egypt.
J Therm Biol. 2021 Feb;96:102833. doi: 10.1016/j.jtherbio.2020.102833. Epub 2021 Jan 13.
This study evaluated the effects of different levels of dietary lipids on the growth performance, feed utilization, body composition and cold tolerance of Nile tilapia (Oreochromis niloticus) fingerlings (7.33 ± 0.12 g fish). Four isonitrogenous (275 g kg crude protein), isocaloric (18.5 MJ kg) diets containing a mixture of fish oil and corn oil (1:1 ratio) at different levels (70, 85, 110 and 130 g kg) were prepared and fed to Nile tilapia reared at a fixed water temperature 25 ± 1 °C for two months. After the feeding trial, the fish were exposed to a cold challenge. The best growth rates and feed utilization were achieved at 70 and 85 g kg dietary lipid, whereas the lowest results were recorded at higher lipid levels (110 and 130 g kg). The ability of Nile tilapia to survive the acute cold stress was significantly improved as the lipid level increased from 70 to 110 g kg and decreased with further increase in lipid levels. During the cold stress, saturated fatty acids (SFA) significantly decreased, while unsaturated fatty acids (UFA) tended to increase. Thus, this study demonstrates, to a certain level, that high dietary lipid levels have a positive effect on the cold tolerance of Nile tilapia fingerlings.
本研究评估了不同水平的日粮脂质对尼罗罗非鱼（Oreochromis niloticus）幼鱼（体重7.33±0.12克）生长性能、饲料利用率、鱼体组成和耐寒性的影响。制备了四种等氮（粗蛋白含量275克/千克）、等热量（18.5兆焦/千克）的日粮，这些日粮含有不同水平（70、85、110和130克/千克）的鱼油和玉米油混合物（比例为1:1），并投喂给在25±1℃固定水温下饲养两个月的尼罗罗非鱼。饲养试验结束后，对鱼进行冷应激挑战。日粮脂质水平为70和85克/千克时，生长率和饲料利用率最佳，而在较高脂质水平（110和130克/千克）时，结果最差。随着脂质水平从70克/千克增加到110克/千克，尼罗罗非鱼在急性冷应激下的存活能力显著提高，而随着脂质水平进一步增加则下降。在冷应激期间，饱和脂肪酸（SFA）显著降低，而不饱和脂肪酸（UFA）则趋于增加。因此，本研究在一定程度上表明，高日粮脂质水平对尼罗罗非鱼幼鱼的耐寒性有积极影响。
