Institute of Marine Sciences, University of Dar es Salaam, P.O Box 668, Zanzibar, Tanzania.
Department of Aquaculture Development, Ministry of Livestock and Fisheries, P.O Box 670, 40404, Dodoma, Tanzania.
Sci Rep. 2021 May 27;11(1):11147. doi: 10.1038/s41598-021-90505-y.
Five introduced strains of Nile tilapia (Oreochromis niloticus) were tested for growth performance both in fresh- and brackish-water (2 salinity units) environments for 56 days. The BIG NIN, GIFT, Chitralada, "Ruvu Farm" and Silver YY strains with initial mean average weight (± standard error) of 96.4 ± 6.90 g, 104.1 ± 7.19 g, 137.2 ± 7.21 g, 53.2 ± 6.98 g and 95.3 ± 7.11 g, respectively were used. Individuals were tagged and pooled in hapas (12 m × 8.5 m × 2 m each), aligned into different ponds (20 m × 20 m each). Stocking density of 5 fish/m and 350 g/kg crude protein diet were used. Overall, the average weight gain for GIFT strain was 7.5%, 32%, 45% and 86.5% higher than BIG NIN, Chitralada, "Ruvu Farm" and Silver YY strains, respectively, across both environments. All strains performed significantly better (p < 0.05) when reared in brackish-water than their respective counterparts in freshwater, except for the BIG NIN strain. The morphometric correlations for all strains in both environments ranged from moderate (0.50) to strong positive (0.92). The GIFT strain demonstrated superior growth and genotype by environment interaction was weak and not important to be prioritized in breeding programs.
五种引进的尼罗罗非鱼（Oreochromis niloticus）品系在淡水和半咸水环境（2 个盐度单位）中进行了为期 56 天的生长性能测试。BIG NIN、GIFT、Chitralada、“Ruvu Farm”和 Silver YY 这五个品系的初始平均体重（±标准误差）分别为 96.4±6.90 g、104.1±7.19 g、137.2±7.21 g、53.2±6.98 g 和 95.3±7.11 g。个体被标记并放入围网（每个 12 m×8.5 m×2 m）中，排列在不同的池塘（每个 20 m×20 m）中。使用的放养密度为 5 尾/米和 350 g/kg 粗蛋白饲料。总体而言，GIFT 品系在两个环境中的平均增重比 BIG NIN、Chitralada、“Ruvu Farm”和 Silver YY 品系分别高 7.5%、32%、45%和 86.5%。所有品系在半咸水中的表现都明显优于在淡水中的表现（p<0.05），除了 BIG NIN 品系。所有品系在两个环境中的形态相关系数从中度（0.50）到强正相关（0.92）不等。GIFT 品系表现出卓越的生长性能，且基因型与环境互作较弱，在选育计划中不重要。
