Abstract
The utilization of stearic acid (SA) and corn starch (Cs) or dextrin (Dx) as energy sources for Macrobrachium rosenbergii (de Man) juveniles, and the effect of increasing dietary SA and digestible energy levels on weight gain, survival, lipid class and fatty acid profiles of the whole body of prawns were determined in a 60-day feeding experiment in a randomized complete block design. The diets contained fixed amounts of carbohydrate (30%) and protein (35%), and increasing levels of SA (0, 2, and 7%) which resulted in an increase of gross energy (14.4, 15.3, 17.2 MJ/kg diet).
Regardless of SA level, Cs and Dx were both utilized effectively for energy by M. rosenbergii juveniles. Regardless of carbohydrate sources, increase in dietary amount of SA resulted in significantly higher content of SA and 18:1 n-(9+11) in the body of prawns, both in the neutral and polar lipid fractions. Weight gains of the prawns were higher in the diets with 2%, then 0%, followed by 7% SA. This indicated that SA were utilized for growth but the contribution was low as energy sources.
The result of the present study showed that M. rosenbergii juveniles utilized SA as an energy source but the contribution of SA as energy source was lower than that of carbohydrates.
