Influence of Dietary Protein Content on Growth Performance, Feed Efficiency, Condition Factor, and Length-Weight Relationship in Cyprinus Carpio During the Summer Season

An investigation was carried out to explore the effect of dietary protein on growth, feed utilization efficiency, condition factor, and length-weight relationships in common carp (Cyprinus Carpio). 3600 C. carpio were sourced from a Mosul fish hatchery and transported to a private farm in Khanki township, where they were divided into four groups of 900 each. Following a day of acclimation, the fish were placed in 4× 4× 3m water culture ponds and fed diets with different protein concentrations (T1: 30%, T2: 28%, T3: 30%, and T4: 35%) for 90 days.  From each group, twenty fish were selected for data collection. Results indicated that the growth parameters, such as daily weight gain, total weight gain, weight gain rate, relative growth rate, metabolic growth rate, and specific growth rate, were higher in fish fed a 28% protein diet (T1) compared to other protein concentrations (T1: 30%, T3: 26%, and T4: 35%). Nutrient utilization parameters, including daily feed consumption, total feed consumption, daily protein consumption, and total protein consumption, were elevated in fish fed with 35% protein (T3). T2 exhibited a significantly higher feed efficiency ratio and protein productive value compared to other diets. The feed conversion ratio was markedly decreased in fish fed a 28% protein diet (T2). Fulton condition factor and modified condition factor were significantly elevated (P< 0.05) with a 28% protein diet (T2), while the relative condition factor decreased. The length- weight relationships indicated isometric growth in T3 (26, 35%), allometric positive growth in T2 (28%), and negative growth in T1 (30%). In conclusion, the study highlighted the superior growth performance and nutrient utilization efficiency in common carp when fed a 28% protein diet (T2).