Effects of feeding frequency on growth, survival, body composition and size variation in long whiskers catfish, Mystus gulio (Hamilton, 1822) fry reared in net cage system

Abstract

Two consecutive experiments (60-day duration each) were conducted to evaluate the effects of four distinct feeding frequencies on growth performance, feed conversion efficiency, survival, size heterogeneity, body composition and economic returns in the long-whiskers catfish, Mystus gulio fry. Four treatments of one (FF1), two (FF2), three (FF3) and four (FF4) daily feeding frequencies were tested in brackishwater net cages (2×1×1 m) stocked with M. gulio fry at 300 number per cage, and fed with a diet at 5–15% of biomass daily. Results exhibited significantly higher growth, protein efficiency ratio, and lower FCR (P < 0.05) in FF3 and FF4 in comparison to FF1 and FF2. In both the experiments, fish in FF3 and FF4 treatments had higher survival rates of 89.6 ± 2.5 and 85.0 ± 2.4%, and 90.4 ± 2.4 and 88.7 ± 2.2%, respectively. Total number of shooters segregated was significantly the highest (P < 0.05) in FF1 (10.67 ± 0.57 and 11.33 ± 1.00) followed by that in FF2, FF3 and FF4. Harvested M. gulio fingerlings in FF2, FF3 and FF4 contained higher organic matter, crude protein and lipid contents (P < 0.05) compared to that of FF1. FF3 and FF4 had markedly elevated gross return, net return and benefit–cost ratio. This study suggests that three times feeding daily is adequate and appropriate for M. gulio fry reared in brackishwater net cages.