Abstract
Wheat grass juice (WGJ) is an extract of young wheat plantlets (Triticum aetivum L.) used worldwide for its health related properties. In this study, the following feeds containing WGJ were tested on common carp (Cyprinus carpio L.): Control (C), WGJ1% (V1), WGJ2% (V2) and WGJ4% (V3) w/w. Fish with an average initial weight of 102 g/individual were grown in a recirculating aquaculture system. The results showed that WGJ had stimulatory effects on growth performance. Accordingly, final body weight increased by 11% at V1, 39% at V2 and 23% at V3, while other indices (feed conversion ratio, specific growth rate, relative growth rate, protein efficiency ratio, and condition factor) were unaffected. Body composition analyses revealed a significant decrease in fat content at V2 and a significant increase in collagen and ash at the same variant, while the protein content was unmodified. Regarding the blood profile, significant increases in the content of albumin, globulin, total protein, and calcium were recorded in the variants with WGJ. The positive results of WGJ on carp can be attributed to its biochemical composition, which is rich in chlorophyll (4.71 mg mL(-1)), total phenols (164 µg mL(-1) gallic acid equivalents), and high antioxidant activity (67% inhibition of DPPH 2,2-diphenyl-1-picrylhydrazyl). The results suggest WGJ can be used as a promising feed additive for common carp.