Comparison of growth performance among the late selected generations of F13-F15 of NEW GIFT strain of Nile tilapia (Oreochromis niloticus)

Abstract:

Growth performance of NEW GIFT strain of Nile tilapia（Oreochromis niloticus）from F13 to F15 was compared at Experimental Station for Fish Germplasm of Shanghai Ocean University for 67 days in 2011. The results showed that: (1) The body weights of F13-15 at the end of the experiment was 195.7g, 213.4g, 218.3g, respectively. Analysis of variance showed that growth rate of F14 and F15 were significantly faster than F13 (P<0.05), but no significant difference was detected between F14 and F15 (P=0.483). (2) The averages of daily body weight gain of F13-15 of the total experiment periods were 2.39 g/d, 2.61 g/d, 2.74 g/d respectively. F15 was 4.98% higher than F14, and F14 was 9.21% higher than F13.The average improvement of growth rate per generation was 7.10%. It could be considered that selection response to growth performance of F13~F15 of NEW GIFT strain was about 7.10%. (3) The variation coefficients of body weight of F13-15 were 6.33%, 4.87%, 1.60% respectively at the end of the experiment, namely F13>F14>F15, which suggested that the variation coefficient decreased with selection progress. It is conjectured that genetic improvement of NEW GIFT strain never stopped in the course of continuous selection. There is a certain distance from the selection limit.