EFFECTS OF CARBOHYDRATE SOURCES ON THE GROWTH, BODY COMPOSITION, INTESTINAL SHORT CHAIN FATTY ACIDS AND LIVER GLYCOGEN OF LEMON FIN BARB HYBRID

The requirement of dietary carbohydrate in fish and crustaceans is still controversial and not completely understood. Understanding the ability of the fish species in utilising carbohydrate is the basis for appropriate feed formulation. In the natural environment, most fish and crustaceans have limited access to carbohydrate sources which are not well adapted to the digestive system for complete metabolism at high levels of dietary carbohydrate. It is believed that the capacity to utilise different carbohydrate sources varies among fish species.

A 60-day feeding trial was conducted to determine the best dietary carbohydrate source for lemon fin barb hybrid fingerlings. Triplicate groups of fish (1.2 ± 0.05 g) were fed twice a day until apparent satiation with five isocaloric (17 kJ g^-1), isonitrogenous (30% protein) and isolipidic (4%) test diets containing 35% carbohydrate from corn, tapioca and sago starches, and wheat and rice flour as carbohydrate sources. At the end of the experiment, the growth, feeding efficiencies, whole body proximate composition, intestinal short chain fatty acids and liver glycogen were measured. The weight gain, specific growth rate, protein efficiency ratio feed conversion ratio and survival were unaffected by the dietary carbohydrate source (P< 0.05). The optimal feed conversion ratio (1.48) and the best protein efficiency ratio (Table 1) were achieved using corn and tapioca starch. The whole body lipid, protein content, carbohydrate, HIS and VSI were also unaffected by the dietary carbohydrate source. No significant difference was found in the intestinal butyric acid among treatments, although acetic acid and propionic acid were higher in fish fed the corn and tapioca starch diets, respectively. The current study showed the high ability of the hybrid to optimally utilise different carbohydrate sources.