Influence of protein content of broodstock diets on larval quality and performance in Nile tilapia, Oreochromis niloticus (L.)

Abstract

Performance of mature Nile tilapia females reared on three isocaloric, purified, diets of 10, 20 and 35% crude protein (CP), for a minimum period of 4 months, in relation to fertilizability, hatchability and larval quality was investigated. Care was taken to minimize the influence of males on egg and larval quality, and to ensure that the results reflect the nutritional history of the brooding females. The eggs of females reared on the 10% CP diet were not fertilized. The means of the number of eggs per spawn, egg diameter and percent fertilizability were 359 ± 31 and 398 ± 39, 2.29 ± 0.05 and 2.31 ± 0.05 mm, and 79.8 ± 4.2 and 83.8 ± 3.9 for females fed on 20 and 35% CP diets, respectively. The differences between the diets for the above parameters were not significant. However, the percent hatchability (20% CP 41.7 ± 5.1; 35% CP 68.7 ± 3.6) of the eggs and the percentage of normal larvae (20% CP 41.8 ± 4.4; 35% CP 59.8 ± 2.8) from the females on 35% CP diet were higher (P