Influence of Feeding an All Plant Ingredients Containing Diet at Different Levels on Growth and Digestive Enzyme Activity of Pond Raised Indian Major Carps

Abstract

A 150 days feeding experiment was conducted in Indian major carps (IMCs) in poly-culture ponds to study their growth and digestive enzymes activity in response to feeding only plant ingredients containing diet, at different levels. Twelve earthen ponds of 0.06 ha were allocated for the experiment. Carp juveniles were stocked at a ratio of 35: 35: 30 of Catla: Rohu: Mrigal with a stocking density of 3500 fish/ha. Fish were fed on an all plant ingredients containing diet at 1.0, 1.5, 2.0 and 2.5% of their biomass in each pond. Triplicate ponds were allocated under each feeding level. The final body weight and net biomass gain were significantly (P<0.05) influenced by the dietary treatments. In all the three species of carps the highest (P<0.05) growth was obtained at 2% feeding level, and thereafter the growth was plateaued. Fish grew the lowest at 1.0% feeding level. Protease, amylase and lipase activities were studied in the three parts of the gastrointestinal tract. For all the species the amylase activity was the highest (P<0.05) in anterior intestine (AI), followed by middle intestine (MI) and posterior intestine (PI). In AI of catla and rohu the protease activity was significantly higher (P<0.05) at 1% feeding level in comparison to that in other dietary treatments. In mrigal and catla the highest lipase activity was determined in AI when fed at 1% level. The digestive enzyme amylase, protease and lipase activities found maximum with 1% feeding level. The study indicated that the best growth of IMC was obtained when fed at 2% of their body weight in pond aquaculture condition.