Effects of chili pepper extract (Caspicum annum) on immune responses, hematology and growth of rainbow trout (Oncorhynchus mykiss)

Abstract

The present study was carried out to investigate the effect of chili pepper extract on the growth, blood parameters, and immune responses of rainbow trout (Oncorhynchus mykiss). Fish with an average initial weight of 9.38±0.01 (g) were fed with diets containing 0, 0.25, 0.5 and 1 (%) of pepper extract in for a month. Based on the results, the highest weight gain, percent of weight gain, specific growth rate and the least food convention ratio was observed in 0.5% treatment. After 15 days, significant changes were observed in all blood parameters among various feeding treatments, (except for globulin), so that 0.25% and 0.5% treatments showed significantly higher red and white blood cell counts, and Hb level compared to other groups (P<0.05). At the end of rearing period, the most concentration of total protein and HCT (%) were detected in 0.25% treatment. With increased time and the concentration of chili pepper extract, lysozyme and complement showed increasing trends and their highest levels were measured in those fish fed with 1% chili pepper extract at the end of rearing period (P<0.05). Regarding the presented results, the use of red pepper extract at 0.25 and 0.5 % is recommended to enhance the weight and immune system of rainbow trout fish against infectious agents.

Keywords

• blood parameters
• chili pepper
• growth rate
• immunity
• rainbow trout.