Wheat and Barley Grass Juice Addition to a Plant-Based Feed Improved Growth and Flesh Quality of Common Carp (Cyprinus carpio)

SIMPLE SUMMARY: Several plant extract additives are being increasingly used in aquaculture for their positive effects on fish growth and immunity. Plant extract additives are called phytogenics. The chemical composition of the additives influences their biological activity. The plant extracts used in this study were wheat grass juice and barley grass juice. Their inclusion in a plant-based diet for common carp improved growth performance and flesh quality. The positive effects of the plant extracts could be attributed to their contents of unsaturated fatty acids, essential amino acids, sugars and organic acids. ABSTRACT: Phytogenics are plant extract additives used for their bioactive properties. The objective of this study was to assess the effect of plant extracts, wheat grass juice (WGJ) and barley grass juices (BGJ) addition to fish diet on growth and meat quality of common carp. Fish (51 ± 33 g initial weight) were fed for four weeks with three plant-based diets: (1) control feed (Con), (2) control feed supplemented with 2% WGJ (Con+WGJ), and (3) control feed supplemented with 2% BGJ (Con+BGJ). The results showed that the inclusion of the two juices in the plant-based feed stimulated the growth and improved meat quality by lowering the fat and ash content. Feed conversion ratio and condition factor were not affected. There were no significant differences in Fe and Zn contents of meat; however, Cu decreased, while Mn was lower in the Con+WGJ group and higher in the Con+BGJ group compared to Con. A high content of unsaturated fatty acids (FA, oleic acid and linoleic acid) and desirable ratios of saturated/unsaturated FA (0.27–0.29) and Ω6/Ω3 (2.5–2.78) were found in all groups. The juices were characterized in terms of lipid profile and polar compounds by GC-MS technique. The observed positive effects can be attributed to the rich composition of juices that included unsaturated FA, amino acids, sugars and organic compounds.