Palm oil is of great potential as one of the sustainable alternatives to fish oil(FO) in aquafeeds.In this present study,five isonitrogenous diets(32% crude protein) with elevated palm oil levels of 0%,2%,4%,6% and 8% were used during an 8-week feeding trial to evaluate its effects on RNA/DNA ratio and lipoprotein lipase(LPL) and Myo D m RNA expressions in muscle of Oreochromis niloticus.The results showed that RNA,DNA content as well as ratio of RNA to DNA were significantly affected(P < 0.05),in each case the highest was recorded in fish group subjected to 6% palm oil level.There was a strong positive correlation between nucleic acid concentration(RNA concentration and RNA:DNA ratio) and specific growth rate(SGR),protein efficiency ratio(PER),while a negative correlation existed between nucleic acid concentration(RNA concentration and RNA:DNA ratio) and feed conversion ratio(FCR).The m RNA expressions of LPL and Myo D in muscle were not significantly affected by the different palm oil levels,although the highest expression was observed in fish fed with 6% palm oil level.There also existed a strong positive correlation between the m RNA expression of LPL,Myo D and SGR,PER,while their correlation with FCR was negative.In conclusion,elevated palm oil affected the RNA,DNA concentration as well as RNA/DNA ratio significantly,although the m RNA expression of LPL and Myo D were not affected significantly by elevated palm oil levels. Palm oil is of great potential as one of the sustainable alternatives to fish oil (FO) in aquafeeds. In this present study, five isonitrogenous diets (32% crude protein) with elevated palm oil levels of 0%, 2%, 4% 6% and 8% were used during an 8-week feeding trial to evaluate its effects on RNA / DNA ratio and lipoprotein lipase (LPL) and Myo D m RNA expressions in muscle of Oreochromis niloticus. The results showed that RNA, DNA content as well as ratio of RNA to DNA were significantly affected (P <0.05), in each case the highest was recorded in fish group subjected to 6% palm oil level. There was a strong positive correlation between nucleic acid concentration (RNA concentration and RNA: DNA ratio and specific growth rate (SGR), protein efficiency ratio (PER), while a negative correlation existed between nucleic acid concentration (RNA concentration and RNA: DNA ratio) and feed conversion ratio (FCR) and Myo D in muscle were not significantly affected by the different palm oi l levels, although the highest expression was observed in fish fed with 6% palm oil level. Here also strong a positive correlation between the m RNA expression of LPL, Myo D and SGR, PER, while their correlation with FCR was negative. conclusion, elevated palm oil affected the RNA, DNA concentration as well as RNA / DNA ratio significantly, although the m RNA expression of LPL and Myo D were not affected significantly by elevated palm oil levels.