Non-gelatinized corn supplemented with [alpha]-amylase at sub-optimum protein level enhances the growth of Labeo rohita (Hamilton) fingerlings

A feeding trial was conducted for 60 days to delineate the effect of both gelatinized and non-gelatinized corn with or without supplementation of exogenous [alpha]-amylase at two level of protein 35% (optimum) and 27% (sub-optimum) on growth, tissue composition and protein sparing effect of carbohydrate in the diet of Labeo rohita fingerlings. Three hundred and sixty fingerlings (average weight 10.00±0.15 g) were randomly distributed in 12 treatment groups with two replicates for each. Twelve semi-purified diets containing either 35% or 27% CP were prepared with different levels of [alpha]-amylase (0, 50, 100 and 150 mg kg[superscript [-]1]) and starch type [gelatinized (G)[solidus]non-gelatinized, (NG)] viz. T₁ (NG, 35% CP, 0 mg kg[superscript [-]1][alpha]-amylase), T₂ (G, 35% CP, 0 mg kg[superscript [-]1][alpha]-amylase), T3 (NG, 27% CP, 50 mg kg[superscript [-]1][alpha]-amylase), T₄ (NG, 35% CP, 50 mg kg[superscript [-]1][alpha]-amylase), T₅ (G, 27% CP, 50 mg kg[superscript [-]1][alpha]-amylase), T₆ (G, 35% CP, 50 mg kg[superscript [-]1][alpha]-amylase), T₇ (NG, 27% CP, 100 mg kg[superscript [-]1][alpha]-amylase), T₈ (NG, 35% CP, 100 mg kg[superscript [-]1][alpha]-amylase), T₉ (G, 27% CP, 100 mg kg[superscript [-]1][alpha]-amylase), T₁₀ (G, 35% CP, 100 mg kg[superscript [-]1][alpha]-amylase), T₁₁ (NG, 27% CP, 150 mg kg[superscript [-]1][alpha]-amylase) and T₁₂ (NG, 35% CP, 150 mg kg[superscript [-]1][alpha]-amylase). The fish were acclimatized to the experimental condition for 24 days during which control diet (NG, 35% CP) was fed. Weight gain percentage, specific growth rate, protein efficiency ratio and apparent net protein utilization of NG corn-fed groups at 42.43% were significantly higher (P<0.05) than the same level of G corn-fed groups. We conclude that 42.43% NG corn supplemented with 50 mg [alpha]-amylase kg[superscript [-]1] feed at sub-optimum level of CP (27%) significantly enhanced the growth and protein in L. rohita fingerling. Addition of dietary [alpha]-amylase to G corn had no added advantage on growth of L. rohita fingerling.