An experimental analysis of the effects of dietary lipid sources and feeding ration on the reproductive performance, egg and larval quality of Nile tilapia, Oreochromis niloticus (L.)

This study investigates the effects of dietary lipid sources on the growth and reproductive performance of Nile tilapia over three consecutive spawnings. Fish were reared using three experimental diets, with the goal of replacing dietary fish oil with palm oil. Three experimental diets and a commercial trout diet was used as the control. The effect of dietary lipid on the growth performance, spawning interval, fecundity, relative fecundity (number of eggs per unit weight), egg size, egg fertilization and hatching rate in addition to an assessment of larval quality was investigated. Growth was significantly (p<0.05) influenced by the source of dietary lipid used. The source of the dietary lipid, however, had no significant effect on the diameter of the eggs, as well as their volume or dry weight. Despite this, relative fecundity was found to be significantly different between fish fed experimental diets and those fed the control diet; there was no difference between those fed the PO and mixed PO: CO diets (p>0.05). Similar results were observed for the egg to body weight ratio (EW: BW) and the inter-spawning interval (ISI) for the fish fed control diet (diet 4). The total fecundity (number of eggs produced per fish) obtained from the fish fed the mixed oil diet (PO: CO) was significantly higher (p<0.05) than from those fed the palm oil and control diets. This study suggests that palm oil can replace fish oil in diets fed to O. niloticus with no subsequent negative effects on the eggs and larval quality.