Crude palm oil as a fish oil replacer in the diet of hybrid lemon fin barb (Barbonymus gonionotus ♀× Hypsibarbus wetmorei ♂) larvae

Hybrid lemon fin barb is developed in Malaysia, crossing silver barb (Barbonymus gonionotus, ♀) and lemon fin barb (Hypsibarbus wetmorei, ♂). To control the over-exploitation of tasty wild lemon fin barb, the wild fish crossed with silver barb by the Malaysian Department of Fisheries. Our recent findings proved that the hybrid larvae show high tolerance to bacterial diseases. Therefore, hybrid lemon fin barb would be a good candidate for tropical aquaculture. In the present study, the effects of increasing the dietary replacement level of fish oil (FO) with crude palm oil (CPO) were investigated for the larval stage of this fast-growing and delicious carp species. Three days after hatching, hybrid larvae were randomly allocated to fifteen ۵-L tanks at the rate of ۵۰ larvae L-۱. Five micro diets were formulated to contain ۰, ۲۵, ۵۰, ۷۵ and ۱۰۰% dietary replacement levels of FO with CPO levels. After ۲۰ days of the feeding trial, dietary replacement of FO with CPO was not affected (p>۰.۰۵) survival and growth of hybrid lemon fin barb larvae. The body tissues of hybrid larvae fed CPO consisted of low (p<۰.۰۵) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) compared to those of larvae fed dietary FO. Partial replacement of FO with CPO in the diets of hybrid lemon fin barb showed no lipid vacuoles in the liver and gut during the challenge test against A. hydrophila. In conclusion, total replacement of FO with CPO is noticeable in the larviculture of hybrid lemon fin barb considering the health status of larvae, ۷۵% replacement of dietary FO with CPO would be more suitable. However, enzyme activities lowered in the early larval period with dietary CPO may be because CPO contains high saturated fatty acids.

Keywords:

Hybrid lemon fin barb , Local carps , Fish oil , Crude palm oil and lipid deposition