Evaluating Zinc or Selenium Supplementation with Pomegranate Peel Extract in Rabbit Diet: Effects on Carcass Traits, Growth Performance, Antioxidant, and Immunological Responses

This study aimed to compare the single and combined effects of dietary supplementation of inorganic zinc (Zn) and selenium (Se) with pomegranate peel extract (PPE) on carcass characteristics, growth rate, antioxidative status, and immune responses of fattening rabbits. The trial lasted for 8 weeks, and the rabbits had an average weight of 587 ± 3.44 g at 5 weeks of age. The treatments included a control group (without supplementation), a PPE group with 200 mg PPE /kg diet, Zn and Se groups with diets fortified with 0.3 mg Se/kg diet and 100 mg Zn, respectively, a PPE+Zn group with both supplements and a PPE+Se group with both substances. The results demonstrate that the supplementation of Zn, Se, and PPE individually or in combination with the diets resulted in improved growth indices. Moreover, the FCR and protein efficiency ratio were enhanced by the supplementation. Slaughter traits and hematological parameters did not display significant alterations among the experimental groups. Serum ALT, AST, urea, total cholesterol, and LDL levels were reduced in the supplemented groups more than in the control group. Moreover, the supplemented groups revealed higher levels of serum immunoglobulin G and immunoglobulin A, along with a tendency towards increased glutathione peroxidase levels and decreased malondialdehyde levels. In conclusion, supplementing the diets of growing rabbits with Zn, Se, and PPE, either individually or in combination, has the potential to enhance growth performance, immune function, and overall health. Notably, no significant differences were observed between the effects of single and combination supplementation.