Effect of Pomegranate Peel on Physiological Status and some Growth Parameters of the Nile tilapia, Oreochromis niloticus

Pomegranate peel, a by-product of fruit processing, can be repurposed as a dietary supplement in fish feed. This study investigated the physiological status of the Nile tilapia and evaluated the effects of pomegranate peel supplementation on their physiological and growth performance. The experiment was conducted at the Central Laboratory for Aquaculture Research (CLAR) of the Agriculture Research Center in Egypt. The Nile tilapia (Oreochromis niloticus) fingerlings were sourced from a farm in Sharkia Governorate, Egypt. A total of 450 fish were used in the experiment—225 for immediate use and 225 fingerlings stored as reserves (average weight: 0.75 ± 0.1g). The fish were randomly distributed into 15 glass aquaria (100L each), divided into four treatment groups and one control group. Pomegranate fruits (Punica granatum) were collected from the Agriculture Research Center. The fruits were peeled, washed, and dried in a forced-air oven at 40 °C for 36 hours. The dried pomegranate peel was incorporated into the diet at different concentrations: T1 (0.5g/ kg), T2 (0.1g/ kg), T3 (1.0g/ kg), and T4 (2.0g/ kg). All groups, including the control, were fed six days per week. Water quality was maintained under optimal conditions for tilapia rearing. Key parameters such as crude protein, crude fat, moisture content, and ash levels in the fish were analyzed. Results indicated that erythrocyte count, hematocrit, and hemoglobin levels were optimal at a supplementation rate of 1%. Leucocyte count increased proportionally with pomegranate peel concentration in the diet, up to 1%. The optimal level of supplementation for enhancing serum IgM was also 1%. Additionally, weight gain (WG) and feed conversion ratio (FCR) were improved with a 1% pomegranate peel dietary additive.