Effect of common mallow (Malva sylvestris) dietary supplementation on growth performance, digestive enzyme activities, haemotological and immune responses of common carp (Cyprinus carpio)

The present study was designed to assess the effect of common mallow (Malva sylvestris) extract diet in common carp (Cyprinus carpio) health parameters such as growth performance, digestive enzyme activity, hematological profile, and immunological responses. In addition, we evaluated the possibility of controlling A. hydrophila infection in common carp during the common mallow extract diet (CM). Diets of common carp were supplemented with three different concentrations (0.1, 0.5, and 1 g kg−1) of common mallow extract. They were fed with common mallow diet for 45 days. At the end of feeding, 0.1 g kg−1 CM diet group showed higher final weight and SGR (p ˂ 0.05), whereas the 0.5 g kg−1 CM diet group showed significantly (p ˂ 0.05) lower FCR rate. The digestive enzyme activity experiment was showed that amylase and lipase activity significantly increased (p ˂ 0.05) in 0.5 g kg−1 CM diet. No hematological parameters changed in all experimental groups. Only 0.1 g kg−1 showed significantly decreased level of red blood cell. In immunological response experiment, serum lysozyme activity, nitroblue tetrazolium reduction, and myeloperoxidase activity significantly increased in different doses of common mallow diet during the 45 days. Result of challenge test with A. hydrophila showed that survival rate in 0.5 and 1 g kg−1 CM diet was significantly lower compared to control. The results elucidated that the CM diet could support nonspecific immune system and growth promoter in common carp. Hence, common mallow can be used in semi-intensive and intensive common carp culture.