Effect of natural (carrot and beetroot) and artificial pigments (astaxanthin) on growth, blood indices, and colour changes in skin, tissue and blood in the diet of rainbow trout (Oncorhynchus mykiss)

A 30-day experiment was carried out to comparison the effect of carrot and beetroot as natural pigments and synthetic astaxanthin on growth performance, hematological parameters, and tissue color in rainbow trout fingerlings. 150 juvenile rainbow trout with initial mean weight of 21.44 ± 1.25g fed diets containing 50 and 100 mg/kg carrot; 100 mg/kg beetroot; 100 mg/kg synthetic astaxanthin and a control diet. Body weight increasing and specific growth rate were higher in fish fed the diet containing 100 mg beetroot than those of the control diet. Hematological study including red blood cell, white blood cell, hematocrit and hemoglobin showed significant differences between treatments (p