The objective of this study was to evaluate,in purified diets, the effects of different levels of crude fiber on the apparentdigestibility and gastrointestinal transit rate in Nile Tilapia. Five circularfishbowls (250 L) with a closed system of water filtering, replenishment andheat for feeding and five digestibility fishbowls with individual filteringreplenishment and heat system were used. Thirty-two fishes, averaging initialweight of 30.65 ± 0.50 were used. A completely randomized design withfive levels of crude fiber (2.5, 5.0, 7.5, 10.0, and 12.5%) and five replicateswas used. It was concluded that increasing levels of crude fiber in purifieddiets significantly affect the apparent digestibility of dry matter, crude proteinand ether extract. Levels up to 5.0% crude fiber did not reduce the apparentdigestibility of dry matter and crude protein and levels up to 7.5% crude fiberdid not reduce the apparent digestibility of ether extract of purified dietin Nile tilapia. However, the increase of dietary crude protein significantlyreduce the gastrointestinal transit rate.
