Comparative juvenile performance assessment of genetically improved Nile tilapia (Oreochromis niloticus L.) under commercial conditions in Bangladesh

摘要

Two on-farm juvenile performance trials were conducted at a hatchery in Bangladesh to compare a genetically improved strain of farmed Nile tilapia (GIFT) and a local strain (LS) produced by commercial operators. A 21-day early nursing trial was conducted in five replicate hapas followed by a 27-day advanced nursing trial in six replicate hapas. The mean feed conversion ratios (FCR), mean specific growth rates (SGR), mean individual final weights, mean production yields and mean survival rates were calculated for both strains. During the early nursing trial, GIFT fry survival rate and overall yield were significantly (p < 0.05) greater than LS values, which in contrast demonstrated better FCR and SGR. Improved performance was demonstrated in terms of FCR, SGR and yield for GIFT during the advanced nursing trial and mean final individual weights were 78 greater for GIFT than LS fish (2.26 g and 1.27 g respectively). Economic analysis indicated GIFT fish produced a net return 84 greater than that of LS fish at the end of the early nursing period, and by the end of the advanced nursing period, this difference had grown further such that GIFT generated a gross return over double that of LS. The results from a survey of tilapia grow-out farmers suggested producers from poor, medium and better-off backgrounds agreed GIFT performed better than traditional strains and is beneficial for aquaculture growth in Bangladesh. However, the results also indicate there may be a greater propensity for better-off farmers to appreciate the potential benefits of improved strains over poorer farmers.