Effects of dietary paprika powder (Capsicum annum) on some growth performance, survival rate, and immunological parameters of zebrafish (Danio rerio)

One of the major objectives in the modern and sustainable aquaculture industry is to increase the feed efficiency and survival rate. The present study is aimed to investigate the effect of paprika powder on some growth performance and immunological parameters in zebrafish for a period of 56 days. In this study, a total of 480 zebrafish fry (initial weight of 0.05g and length of 1.71 mm) were randomly divided into 12 tanks and fed with 0 (control), 1, 2, and 3 g of paprika powder per 100 gram of feed. The results of the growth indices and survival rate indicated that the highest weight gain (0.42±0.02 g) and body weight increase (0.36±0.03 g) was observed in 3% of paprika powder (P<0.05).Immunological serum parameters including lysozyme, IgM, complement components (C3 and C4) which represented significant differences in comparison with the control group (P<0.05). The highest activity level of lysozyme was observed in 3% of paprika powder and the highest levels of C3 and IgM were measured in both 2% and 3% of paprika powder. Moreover, addition of paprika powder at different levels without any significant differences between the treatments increased C4 level compared to the control group (P<0.05). On the whole, dietary supplementation of paprika powder in zebrafish feed at the level of 3% led to the improvement of the growth performance as well as immunity modulation and probably can act as an immunostimulant.