Effects of feeding rate on growth, feed utilization and body composition of a tropical bagrid catfish

A 10 week experiment was conducted to determine the effects of feeding rate on growth, feed utilization and body composition of the tropical bagrid ca tfish, Mystus nemurus. Catfish fingerlings with an average initial body wei ght of 12 g were fed a practical diet (36.2% protein, 16.5 kJ/g diet) at ra tes of 1, 2, 2.5, 3, 3.5, 4 or 5% of their body weight (BW) per day in two equal meals. Water temperature was approximately 29 degrees C throughout th e experiment. Percent weight gain increased almost Linearly with increasing feeding rates up to 2.5% BW/day beyond which no significant (P > 0.05) imp rovement in weight gain was observed. The specific growth rate of catfish f ed rations of 1% BW/day was 0.72%/day and this increased significantly to a n average of 1.39%/day for catfish fed 2.5% BW/day and beyond. Feed utiliza tion did not differ significantly (P > 0.05) between fish fed 1.0 to 2.5% B W/day but decreased when rations were increased to 3.0% BW/day and above. F eed efficiency ratio was 0.79 for catfish fed 1.0% BW/day compared to a rat io of 0.27 for fish fed at 5% BW/day. Catfish fed 1.0% BW/day had the lowes t condition factor, hepato- and viscerosomatic indices, but the highest car cass to body weight ratio. These fish also had lower proportions of whole b ody dry matter, lipid and protein, carcass dry matter and lipid, and viscer al dry matter and lipid than fish in other groups. There were no significan t differences in either condition indices or relative body composition of f ish fed rations of 2.0 to 5.0% BW/day. Based on the growth, feed efficiency and body composition data obtained, a feeding rate of 2.5% BW per day is r ecommended for M nemurus fingerlings raised at 29 degrees C.