Comparison of growth performance of F6, F7 and F8 of GIFT strain Oreochromis niloticus

Tilapia is one of the major fish species cultured in the world; genetic improvement of tilapia is very important. Growth performance of GIFT strain of Nile tilapia Oreochromis niloticus was checked by communal testing in concrete ponds. F6, F7 and F8 were compared from seedling in 2004. The averages of daily body weight gain of F6, F7 and F8 were 1.07, 1.12 and 1.47 gd-1, respectively, after raised for 114 days. After correcting the bias (which may caused by the weight because F8 was bigger in weight than F7 and F6 at the beginning), the body weight gain rate of F6, F7 and F8 was 1.13, 1.18 and 1.36 gd-1, respectively. Variation coefficient of body weight of F8 was lower than F7 by 6.29%, and lower than F6 by 7.95%. Growth equation of F8 was: y=40.313x－61.670 (R2=0.8783，R=0.9513).