Fisheries Application and Research Center & Department of Aquaculture, Eğirdir Fisheries Faculty, Isparta University of Applied Sciences, Eastern Campus, 32260, Isparta, Turkey.
Mediterranean Fisheries Research Production and Training Institute, Beymelek Unit, Demre, Antalya, Turkey.
Fish Physiol Biochem. 2024 Dec;50(6):2357-2372. doi: 10.1007/s10695-024-01391-w. Epub 2024 Aug 10.
Expansion of economically viable turbot (Scophthalmus maximus) aquaculture depends on access to brackish-cold ground water sources in various parts of the world. Since brackish water sources can adversely affect the physiology and zoo technical performance of fish due to the burden of osmoregulation, dietary salt inclusion can alleviate the negative impacts of low-saline waters in several aquaculture species. This study investigated the effects of increasing dietary salt levels on the growth, feed utilization, body composition, and tissue fatty acid composition of juvenile turbot (initial live weight 120.3 ± 0.03 g/fish). Fish were fed five experimental diets supplemented with varying levels of sodium chloride (1.8-6.4%) or a control diet without salt. Each diet was tested in triplicate tanks for 9 weeks. Results showed that increasing dietary salt intake negatively impacted turbot performance, with significant reductions in weight gain, specific growth rate, and feed conversion ratio. Dry matter and ash content in the whole body and filet increased quadratically with increasing salt levels, whereas gill moisture and protein content decreased linearly. Furthermore, the nitrogen, lipid, and energy utilization efficiencies decreased with their respective intake and gain levels. Dietary salt significantly influenced the fatty acid profiles of gill, liver, and filet tissues. In the gill, monounsaturated fatty acids (16:1n-7, ΣMUFA) and n-6 PUFA (20:2n-6) increased, whereas EPA and DHA decreased. Liver ΣSFA (16:0, 18:0) increased, and n-3 PUFA (18:3n-3, 20:5n-3) decreased with increasing dietary salt. Filet saturated fatty acids (14:0, 15:0, 17:0) and n-6 PUFA (20:2n-6, 20:4n-6) increased, while n-3 PUFA (18:3n-3, EPA) decreased with dietary salt. DHA levels in filets showed a quadratic increase. Overall, this study shows that increasing dietary salt negatively impacts turbot growth, feed utilization, and tissue fatty acid composition in brackish water, highlighting the need for further studies on salinity management strategies for turbot aquaculture.
经济可行的大菱鲆（Scophthalmus maximus）养殖的扩张取决于在世界不同地区获得咸淡水源。由于低盐度水源会因渗透压负担而对鱼类的生理和养殖性能产生不利影响，因此在饲料中添加盐分可以减轻几种养殖鱼类低盐度水的负面影响。本研究探讨了增加饲料盐度对幼体大菱鲆（初始体重 120.3±0.03g/尾）生长、饲料利用、体组成和组织脂肪酸组成的影响。试验用 5 种实验饲料喂养鱼，饲料中分别添加了 1.8-6.4%的氯化钠或不含盐的对照饲料。每种饲料在 3 个重复水族箱中进行了 9 周的测试。结果表明，增加饲料盐度摄入会对大菱鲆的生长性能产生负面影响，体重增长率、特定生长率和饲料转化率显著降低。随着盐度的增加，鱼体和鱼片的干物质和灰分含量呈二次增加，而鳃水分和蛋白质含量呈线性降低。此外，氮、脂和能量利用率随其摄入量和增益水平的降低而降低。饲料盐度显著影响了大菱鲆鳃、肝和鱼片组织的脂肪酸谱。在鳃中，单不饱和脂肪酸（16:1n-7，ΣMUFA）和 n-6 PUFA（20:2n-6）增加，而 EPA 和 DHA 减少。随着饲料盐度的增加，肝脏ΣSFA（16:0、18:0）增加，n-3 PUFA（18:3n-3、20:5n-3）减少。鱼片饱和脂肪酸（14:0、15:0、17:0）和 n-6 PUFA（20:2n-6、20:4n-6）增加，而 n-3 PUFA（18:3n-3、EPA）减少。鱼片 DHA 水平呈二次增加。总的来说，本研究表明，在咸水中增加饲料盐度会对大菱鲆的生长、饲料利用和组织脂肪酸组成产生负面影响，突出了大菱鲆养殖中盐度管理策略进一步研究的必要性。
