DIETARY CARBOHYDRATE LEVEL ON GROWTH PERFORMANCE OF SPECKLED CATFISH, PSEUDOPLATYSTOMA CORUSCANS

摘要

Carbohydrates are a relatively inexpensive and a readily available source of energy to many fish species. However, some controversy persists about the beneficial effects of the inclusion of carbohydrates in fish diets. The objective of the present work was to evaluate the performance of juvenile speckled catfish Pseudoplatystoma ooruscans ("surubim") fed diets containing varying levels of carbohydrates. Two hundred and eighty eight fingerling of speckled catfish (1.84 +- 0.06g) were stocked in 60-L net cages, placed in a 12-m~3 concrete tank, under a water reuse system, in a completely randomized design. Fish were fed until apparent satiation twice a day (18hOOm and 22hOOm), for 60 days, with isonitrogenous and isoenergetic diets, with increasing levels of carbohydrates: 9%, 13%, 17%, 21%, 25%, 29%. Weight gain and specific growth ratio increased with increased levels of dietary carbohydrate. Fish fed the -diet containing 29% CHO showed the highest values for weight gain and specific growth ratio.Although feed intake was not affected by dietary carbohydrate level, fish fed with 25 and 29% CHO presented better feed utilization than fish fed g 13% CHO. Viscera somatic index and intraperitoneal fat index were affected by dietary carbohydrate level and decreased with increasing dietary carbohydrate. Speckled catfish can be raised on diets containing up to 29% total carbohydrates.