EFFECT OF FEEDING STRATEGY AND CARBOHYDRATE SOURCE ON CARBOHYDRATE UTILIZATION BY WHITE STURGEON (ACIPENSER-TRANSMONTANUS) AND HYBRID TILAPIA (OREOCHROMIS-NILOTICUS X OREOCHROMIS-AUREUS)

Two 8-week growth trials were conducted to determine the effect of con tinuous (CF) versus 2 meals day(-1) (MF) feeding and 30% starch versus 30% glucose diets on the carbohydrate utilization of 9.0-g white stur geon and 0.56-g hybrid tilapia. The two trials were conducted under si milar conditions except that sturgeon were kept at 18.5 degrees C in a flow-through system and tilapia were kept at 26 degrees C in a recirc ulating system. Significantly (P less than or equal to 0.05) higher sp ecific growth rate (SGR), feed efficiency (FE), protein efficiency rat io (PER), body lipid content and liver glucose-6-phosphate dehydrogena se (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) activities wer e observed in the CF than MF sturgeon. Only SGR, FE and PER were highe r in sturgeon fed the starch than the glucose diets. Only higher liver G6PDH and malic enzyme (ME) activities were observed in the CF than M F tilapia but higher SGR, FE, PER and liver G6PDH, 6PGDH and ME activi ties were observed in tilapia fed the starch diet than those fed the g lucose diet. This suggested that carbohydrate utilization by sturgeon was more affected by feeding strategy whereas tilapia was more affecte d by carbohydrate source. Furthermore, white sturgeon can utilize carb ohydrates better than hybrid tilapia regardless of feeding strategy an d carbohydrate source.