Evaluation of the effects of pumpkin seed extract (Cucurbita pepo) on growth factors, serum immune factors, and resistance to Yersinia ruckeri in rainbow trout (Oncorhynchus mykiss)

Previous research has studied the effects of Cucurbita pepo extract on aquatic growth and health parameters. The present study aims to investigate the effects of C. pepo extracts on some blood factors and growth indices of rainbow trout, as well as the resistance of fish to Yersinia ruckeri. A total of 750 rainbow trout, with an average weight of 40-120 g, were randomly selected. The daily amount of feed required was calculated as a function of fish weight and water temperature. The indices of white blood cell (WBC), red blood cell (RBC), and lymphocyte counts were calculated. SPSS version 26 was used for statistical analysis. The results indicated that there was a significant difference between the experimental and control groups in the case of SGR, FCR, and SR, as well as, in hematological parameters, including WBC and RBC, but there was no significant difference between the two groups in the number of rainbow trout lymphocytes (P>0.05). C. pepo extract was effective on rainbow trout IgM and lysozyme levels, and there was a significant difference between the two groups (P<0.05). C. pepo extract was effective on the bactericidal rate of rainbow trout and there was a significant difference between the two groups (P<0.05). The results of this study provide a new perspective on the use of pumpkin seed (C. pepo) extract as a medicinal plant to improve hematological parameters, growth markers and immune response of rainbow trout (Oncorhynchus mykiss).