Effects of dietary pyridoxine on growth and biochemical responses of Labeo rohita fingerlings exposed to endosulfan

Abstract

A sixty-day experiment was carried out to study the effect of dietary pyridoxine (PN) on growth performance, RNA/DNA ratio and some biochemical parameters of Labeo rohita fingerlings exposed to sub-lethal dose of endosulfan (1/10th of 96h static non-renewal LC50=0.2ppb) to assess the role of pyridoxine in ameliorating the negative effects of endosulfan. Two hundred seventy fingerlings (6.5±0.26g) were randomly distributed into six treatments in triplicates (15fish/tank). Five iso-nitrogenous (35.45–35.75% crude protein) purified diets were prepared with graded levels of pyridoxine. Six treatment groups were T0 (10mg PN+without endosulfan), T1 (0mg PN+endosulfan), T2 (10mg PN+endosulfan), T3 (50mg PN+endosulfan), T4 (100mg PN+endosulfan) and T5 (200mg PN+endosulfan). Weight gain (%), specific growth rate (SGR), tissue glycogen, and protease activity were significantly (P<0.05) higher in pyridoxine fed groups compared to their non-pyridoxine fed counterpart. Protease activity was positively correlated (R2=0.931) with (%) weight gain. Glucose-6-phosphate dehydrogenase (G6PDH) activity was significantly (P<0.05) higher in non-pyridoxine fed group and decreased in pyridoxine fed counterparts. There were no significant (P>0.05) effect of dietary pyridoxine on feed conversion ratio (FCR), protein efficiency ratio (PER), survival, gastro-somatic index (GSI), hepato-somatic index (HSI) and liver and muscle DNA levels of L. rohita fingerlings. RNA levels, both in liver and muscle, increased significantly (P<0.05) in pyridoxine fed groups. A positive correlation was observed between growth and RNA levels, both in liver (R2=0.91) and muscle (R2=0.88). RNA/DNA ratio showed a third order polynomial relationship with dietary pyridoxine, both in liver (Y=−0.014x3+0.1613x2−0.5333x+0.7933, R2=0.987) and muscle (Y=−0.0407x3+0.4763x2−1.6358x+2.4667, R2=0.9345). The overall results obtained in present study indicated that dietary pyridoxine supplementation at 100 or 200mg PN/kg diet ameliorates the negative effects of endosulfan and restores optimal growth of L. rohita fingerlings.