Research Article
Imtiaz Ahmed and Amir Maqbo
Abstract
An 8-week feeding trial was conducted to study the effects of dietary protein levels on the growth, feed utilization and haemato-biochemical parameters of mirror carp, Cyprinus carpio specularis (1.50 ± 0.02 g; 4.5 ± 0.05 cm). Six casein-gelatin based isocaloric (367 kcal 100 g-1, gross energy) diets containing graded levels of dietary protein (25%-50% CP) were formulated. 20 fish were randomly stocked in triplicate groups in 75L circular trough fitted with continuous flow-through system and fed experimental diets at 4% BW/day at 0800 and 1700h. Maximum live weight gain (258%), best feed conversion ratio (FCR) (1.63) and protein efficiency ratio (PER) (1.53) were obtained in fish fed diet containing 40% dietary protein. However, quadratic regression analysis live weight gain, FCR, PER and body protein deposition (BPD) data indicated requirements for dietary protein at 43.5%, 41.6%, 34.7% and 37.3% of dry diet, respectively. Significantly higher whole body protein, low moisture and intermediate body fat contents were recorded at 40% protein containing diet (P<0.05). While minimum ash content was recorded at 25% protein level. The highest HIS value (3.39%) was observed at the lowest protein level. Significant differences were also observed in Hb, HCT and RBC values of different groups fed with varying levels of dietary protein (P<0.05). Whereas, no significant differences were observed in their WBC count except at 25% protein level, where higher WBC count was recorded (P>0.05). Based on the above results, it is recommended that 41.5% protein level would be useful for optimum growth and efficient feed utilization of this fish species.