Protein and energy maintenance and optimum feed requirements are reported in the catfisb, Clarias batrachus (L.), fed a purified diet (40% CP; 1487-lkJ/lOOg) at 0 to 8% (BW/day) ration levels. Linear (/• = 0-985) increase was observed in daily average growth increment up to a ration level of 4% (BW/day), corresponding to6 03g protein/(kg'"' BW/day) and 224-26 kJ encrgy/Ckg**" BW/day). Maintenance requirements, obtained by regressing daily average growth increment to zero, were 0-942 g/(kg''*' BW/day) for protein and 36-02 kJ/Ckg"'* BW/day) for energy. Net gains in muscle protein and energy also depicted linear increase (r = 0 975) with feeding levels up to 6-03g protein/(kg'"' BW/day) and 224-26kJ energy/(kg'"' BW/day). On fitting the above data to regression equations, giving the amount of dietary protein and energy required to maintain a constant amount of body protein and energy, values of l-005g/{kg"" BW/day) and 42-11 kJ/(kg*"' BW/day) were obtained for protein and energy respectively. The optimum feeding rate for this species, as evident from specific growth rate and conversion efficiencies, appears to be 3% (BW/day) at 30 ± 2°C. Moisture and lipid contents in muscle were found to be significantly (P < 0-05) affected by the ration levels.

A 63-days indoor feeding trial was conducted to assess the growth performance of Labeo rohita fingerling (69.82±0.53 g) fed with three experimental diets containing black thorn, Kaempferia galanga as natural attractant, yeast as probiotic and their combination. Comparable feed consumption in groups fed with attractant (86.54 g) and combination of attractant and probiotic (85.17 g) compared to group fed probiotic only (74.10 g) were observed. Combined use of attractant and probiotic in the diet resulted in highest percent live weight gain (105.30%) compared to the individual inclusion of attractant (60.88%) and probiotic (72.63%). Comparison of feed conversion ratio (FCR) indicated better conversion when fed with the diet containing both the attractant and probiotic (3.69) compared to the other diets containing either probiotic (4.96) or attractant (5.20). Further, highest accretion of carcass protein was recorded in groups fed diet with combination of additives (254.79%), followed by attractant (193.03%) and probiotic (159.29%) alone. RNA/DNA ratio in both liver and muscle exhibited a significant (P<0.05), linear increase in groups fed diet with only probiotics followed by attractant alone, and the combination of both probiotics and attractant accordingly. Present study revealed better efficacy of feed supplemented with Kaempferia galanga in feed consumption, growth promotion and utilization in L. rohita fingerlings, as compared to that with probiotic.However, the combination of probiotics and attractant could confer the better results as compared to their individual dietary inclusion.