Effects of Microalgae on Nutrigenomics and Stress Biomarkers in Koi Carp, Cyprinus Carpio, (LINNAEUS, 1758) Raised in Aquaponic System

Abstract

This study evaluated the dietary effects of freshwater microalga, Spirulina platensis on the growth performance, nutrient utilisation and stress biomarkers in Koi carp, Cyprinus carpio fingerlings raised in aquaponic system with fluted pumpkins. Five feeds were formulated with different inclusion levels of spirulina at 0, 25, 50, 75 and 100% each representing treatment 1 (control), 2, 3, 4 and 5 respectively. The aquaponic system used is a pyramid Nutrient Film System (NFT) using a Poly Vinyl Chloride base with a small hole made for plant to float placed in a small disposable plastic filled with growth media and conventionally used Gravel (granite stones) which was used as control to support the plants for the plant to grow. The result showed that were significant differences (P<0.05) in the growth and nutrient utilization parameters with treatment 4 with 75% spirulina inclusion having the best protein efficiency ratio, feed conversion and feed efficiency ratios. The results from the stress biomarker analysis indicated that Spirulina platensis reduced liver stress and enhances liver function in Cyprinus carpio fingerlings, as evidenced by the decreasing ALT and AST levels in the liver of fish with spirulina diets.