Effect of spawning month, dietary protein and pond protection on fry production of the Nile tilapia, Oreochromis niloticus

Abstract

The practical work of the present experiments was carried out at the World Fish Center, Abbassa, Abou Hammad, Sharkia, Egypt. The experiment aimed to investigate the effect of spawning month (April and May), dietary protein level (25 or 35%) and protection of spawning tanks (covering or uncovering of the spawning tanks) on fry production and average fry weight of the Nile tilapia. The obtained results can be summarized as follow:-Fry production/tank were found to be 6462 and 19082/tank during the two months April and May, 10719 and 14824/tank for the two dietary protein levels, 25 and 35% and 16428 and 9115 fry/tank for the covered and uncovered tanks, respectively and the differences in fry production due to the effect of spawning month, dietary protein content and tank protection were significant.-Averages of individual fry weight as affected by month, dietary protein levels and pond protection were found to be 0.025 and 0.016 g during the two months April and May, 0.021 and 0.019 g for the two dietary protein levels, 25 and 35% and 0.018 and 0.023 g for the covered and uncovered tanks, respectively. Spawning month and tank protection significantly affected individual fry weight while dietary protein levels had no significant effect on fry weight.-The interaction between the studied factors affected individual fry weight of the Nile tilapia indicated that the highest average individual fry weight was recorded for fish group raised in covered tanks and received the lower protein content during April. On the other hand, the lowest average individual fry weight was recorded for broodfish raised in an uncovered tanks and received the higher protein level (35%) in May.

EVALUATION OF EARLY MATURITY ASPECTS OF TWO EGYPTIAN NILE TILAPIA (Oreochromis niloticus) STRAINS: ABBASSA IMPROVED AND MANZALA COMMERCIAL WITHIN A DIALLEL CROSSING

“…Gonad weight was highly correlated with GSI in both males and females (0.96 and 0.97, respectively). These results are in agreement with Sultan et al (2011) who reported significant and positive correlation coefficients between tilapia body length and ovary weight (0.51); body length and GSI (0.39); body weight and ovary weight (0.61); body weight and GSI (0.42). The current results indicate that whenever males and females body weight or length increase, the gonads weight and GSI will be also increased.…”

Role of dietary L-carnitine supplements on improving of reproductive performance of Nile tilapia (Oreochromis niloticus)

“…This indicated that, the fry number produced per fish for diet contained 600 mg L-carnitine/kg diet was better than those of other treatments. Soltan et al, (2012) reported that, Dietary protein and L-carnitine has been found to influence seed production in tilapia. An increase in egg production with an increase in L-carnitine levels has been reported for Nile tilapia, O. niloticus (Santiago, et al, 1985) and Taiwanese red tilapia (Chang et al, 1988).…”