Effects of dietary lipid source on egg and larval quality of Nile tilapia, Oreochromis niloticus (L.).

Abstract

This study investigated the effects of dietary lipid sources on reproductive performance of Nile tilapia for three consecutive spawnings with the goal of replacing dietary fish oil with palm oil. In this study tilapia were fed solely with the selected experimental diet during their entire life, from onset of exogenous feeding until termination of spawning. Three isonitrogenous (40% crude protein), isoenergitic (20 KJg) experimental diets were made containing either 10% cod liver oil (CO), palm oil (PO) or mixed palm and cod liver oil (9:1 ratio; PO&CO) using soybean protein concentrate as the protein source. In addition a commercial trout diet was used as a control. The influence of dietary lipid on spawning intervals, fecundity, relative fecundity (egg number per unit weight), egg size, fertilisation and hatching rate and larval quality was investigated. Dietary lipid sources had no significant effect on egg diameter, egg volume and egg dry weight. However, relative fecundity was significantly (P 0.05). Similar results were observed for egg weight to body weight ration (EW: BW) and inter spawning interval (ISI) for fish fed diet 4. Moreover, total fecundity (number of eggs produced per fish) obtained from fish fed the mixed oil diet (PO & CO) was significantly (P<0.05) higher than for those fed the palm oil and control diets. This study suggests that palm oil can replace fish oil with no negative effect on egg and larval quality in O. niloticus.