Growth and body composition of rohu (Labeo rohita) fed diets containing oilseed meals:: partial or total replacement of fish meal with soybean meal

A 56-day feeding trial was conducted to evaluate growth, feed utilization and body composition of fingerling rohu, Labeo rohita (4.5 +/- 0.2 cm; 2.58 +/- 0.04 g), fed five isonitrogenous (350 g kg(-1) crude protein) and isoenergetic (15.7 kJ g(-1) metabolizable energy) diets in which the main protein contributors were: diet I, fish meal (FM); diet II, soybean meal (SBM); diet III, groundnut meal (GNM); diet IV, equal amounts of SBM, GNM and canola meal (CM); diet V, equal amounts of FM, SBM, GNM and CM. Fish were stocked in triplicate groups of 25 fish held in 70 L flow-through tanks (water volume 55 L) and fed twice daily (0900 and 1700 hrs) to apparent satiation. Fish fed diet I exhibited the highest (P < 0.05) values for live weight gain and specific growth rate (% per day). Feed conversion and protein efficiency ratio were better (P < 0.05) in fish-fed diets I and II. Fish-fed diet II exhibited lower (P < 0.05) fat and ash contents in carcass. Based on these findings, a 70-day trial (Experiment II) was conducted with six diets fed under the same conditions where FM was incrementally replaced with SBM. Fingerling L. rohita (6.7 +/- 0.4 cm; 4.07 +/- 0.02 g) were used for the study. Crystalline L-methionine was added to diets containing more than 250 g kg(-1) SBM. This second study showed no significant (P > 0.05) variation in growth, feed utilization and carcass composition for fish fed the different diets. In conclusion, SBM was more effective than GNM or CM, as FM was replaced in feeds for fingerling L. rohita and could completely replace FM when supplemented with methionine and fortified with minerals under the conditions of this study.