Studies on Growth Responses of Fish During Chronic Exposures of Nickel and Manganese
2006
Muhammad Javed
Three fish species viz. Catla catla, Labeo rohita and Cirrhina mrigala were exposed to sub-lethal concentrations of nickel and manganese for 30 days. During these trials, fish were fed to satiation daily with the feed having Digestible Energy (DE) of 2.90 Kcal g<SUP>-1</SUP> and 35% Digestible Protein (DP). 30-day sub-lethal exposure stress of metals to the fish caused no mortality. However, average weight, fork and total length increments of three fish species varied significantly during nickel and manganese chronic exposures. Catla catla were significantly more sensitive to manganese than nickel toxicity. During stress of both nickel and manganese, both Labeo rohita and Cirrhina mrigala exhibited decrease in their weights. However, this chronic stress did not exert any significant effect on feed intake of fish while the responses of three fish species were significantly variable. Chronic exposure of metals to both Catla catla and Labeo rohita exerted significant impact on the accumulation of nickel, followed by that of manganese in their bodies.
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