The potential of tomato pomace as a feed ingredient in common carp (Cyprinus carpio L.) diet

Aquaculture dependency on component feed has increased attention to alternative feedstuffs for conventional ingredients such as fish meal, oil seeds and grains. The main aim of this study was to evaluate growth performance, nutrients digestibility and body composition in common carp (Cyprinus carpio) fed diet with different levels of tomato pomace. Four experimental diets were formulated with similar protein content: a control diet and three experimental diets with increasing tomato pomace levels (10%, 20% and 30%). Each diet was randomly assigned to triplicate 300 I tanks. Common carps with an initial weight of 16.50 +/- 0.7 g were randomly distributed in the experimental tanks. The experiment lasted for eight weeks. Results showed that 10% inclusion of tomato pomace significantly increased the final weight and specific growth rate (P < 0.05) of common carp compared to the control diet. Feed conversion ratio and weight gain were also improved after 10% tomato pomace diet was given to the experimental fish (P < 0.05). Dietary addition of 10% tomato pomace also improved apparent digestibility coefficients (ADCs) of dry matter and fat (P < 0.05). However, protein ADC was decreased with increasing of tomato pomace inclusion (P < 0.05). Body composition was not influenced by the tomato pomace inclusion (P > 0.05). Moreover, feeding on tomato pomace elevated plasma cholesterol concentration of the common carp (P > 0.05). We conclude that common carp can utilize the tomato pomace up to 30% with no negative impact on growth.