β‐Carotene of Arthrospira platensis versus vitamin C and vitamin E as a feed supplement: Effects on growth, haemato‐biochemical, immune‐oxidative stress and related gene expression of Nile tilapia fingerlings

Microalgae are one of the most important sources of natural bioactive compounds, especially those revealing antioxidant activity such as β‐carotene. Thus, this study was to compare the effects of dietary Vitamin C (L‐ascorbic acid) or Vitamin E (α‐tocopherol) with β‐carotene extracted from Arthrospira platensis on Nile tilapia (Oreochromis niloticus) on growth, feed utilization, blood indices, antioxidant activity, non‐specific immunological indices and related gene expression. Three hundred and sixty apparent healthy Nile tilapia (5.80 ± 0.286 g) were randomly distributed into four groups. Four isonitrogenous and isoenergetic diets were performed. A control diet was compared against three experimental diets supplemented with Vitamin C (0.5 mg kg−1 diet), Vitamin E (1 g kg−1 diet) or β‐carotene (0.5 g kg−1 diet) for 10 weeks. According to the results, there was no significant difference in feed intake (p > 0.05) between experimental diets. Dietary Vitamins C and E and β‐carotene significantly (p