Immunohematological parameters of rainbow trout (Oncorhynchus mykiss) fed supplemented diet with different forms of barberry root (Berberis vulgaris)

In this experiment, the effect of barberry root powder and methanol extract on the growth and immunohematological parameters of rainbow trout (Oncorhynchus mykiss) was studied. A total of 306 rainbow trout fingerlings (15.55 ± 0.76 g) were fed for 8 weeks with six experimental diets: control (C), BRP10 (10 g kg⁻¹ of barberry root powder), BRP20 (20 g kg⁻¹ of barberry root powder), BRE250 (250 mg kg⁻¹ of barberry root extract), BRE500 (500 mg kg⁻¹ of barberry root extract), and oxytetracycline OTC30 (30 g kg⁻¹). The results indicated BRE250, BRE500, and OTC30 had significantly higher weight gain (93.04, 92.52, and 90.48 g, respectively) compared with other dietary treatments (P < 0.05). The highest levels of WBC (26.5 × 10³), RBC (1.8 × 10⁶), HB (9.47 g dl⁻¹), MCHC (22.19 g dl⁻¹), lymphocytes (67.67%), lysozyme (65.67), and ACH50 (139) in fish fed BRE500 diet were observed (P < 0.05). Also, inhibition zone appeared with the barberry against Aeromonas hydrophila in vitro. Totally, it is suggested that the BRE500 diet can be used as a natural stimulant of growth and immunity in the aquaculture industry.