THE EVALUATION OF ARTHROSPIRA PLATENSIS BIOACTIVITY AND THEIR DIETARY SUPPLEMENTATION TO NILE TILAPIA VEGETARIAN DIET ON GROWTH PERFORMANCE, FEED UTILIZATION, BODY COMPOSITION AND HEMATO-BIOCHEMICAL PARAMETERS

The present study aimed to identify the carotenoid content and evaluate the antioxidant activities of spirulina, Arthrospira platensis (in vitro), and the effect of its supplementation to a vegetarian diet on growth performance, feed utilization, body proximate composition and physiological status of Nile tilapia, Oreochromis niloticus (in vivo). The carotenoid content of spirulina was identified by UPLC-MS/MS and showed that trans and cis beta-carotene were the major carotenoids (88.3%) followed by beta-cryptoxanthin and zeaxanthin. The antioxidant activity of spirulina was determined in water and crude carotenoid extracts by 2,2-diphenyl-1-pieryhydrazyl (DPPH) scavenging assay, both extracts showed a significant free radical scavenging capacity. In addition, Nile tilapia fry (0.83 +/- 0.01 g) was fed a vegetarian diet supplemented with different levels of spirulina for 12 weeks. The results revealed that the highest growth performance and nutrient utilization were recorded with 0.5% spirulina and the peak response determined at 0.63%-0.65% using polynomial second order regression. Also, the hemoglobin content improved in a quadratic regression model with the peak at 0.67% spirulina. Plasma total protein and lipid contents increased significantly with spirulina levels over 0.50%. Moreover, the aminopeptidase activities and glucose level decreased significantly with increasing spirulina levels. The current study recommended the supplementation of the Nile tilapia vegetarian diet with spirulina at levels of 0.63-0.65% for better growth performance and physiological status.

Automated summary

The study identified the carotenoid content and antioxidant activities of spirulina, as well as its effect on growth performance of Nile tilapia. The results showed that supplementation of 0.63-0.65% spirulina in vegetarian diet improved growth performance and physiological status of the fish.