Evaluation of Houttuynia cordata Thunb. leaf extract on growth performance, feed utilization, and hematological indices of hybrid catfish (Clarias macrocephalus × Clarias gariepinus)

Abstract

This research evaluates the effects of Houttuynia cordata thunb. leaf extract on growth performance, feed utilization and the hematological indices of Hybrid catfish (Clarias macrocephalus × Clarias gariepinus). Four groups of fish were divided and given a basal diet (control group) as well as the extract solution, which was sprayed into the commercial fish feed (30% crude protein) in the amounts of the extract, 50, 70 and 100 ml/kg feed, then fed to the experimental fish for 90 days. Dominant results for the growth indices were found on days 15 and 30 of the experimental period. A significantly increased level (p < 0.05) of average daily growth (ADG), specific growth rate (SGR), feed efficiency (FE) and protein efficiency ratio (PER), as well as the lowest feed conversion rate (FCR), were found in fish fed with H. cordata extract at 70-ml/kg feed on day 15. While on day 30, it was revealed that the ADG, SGR, and PER were at their highest values in fish fed 50 ml/kg. Meanwhile, the survival rate was significantly different only at the end of the experiment (day 90) and was at its highest rate in the group fed 100 ml/kg. The highest total red blood cell levels (RBC) were observed in groups fed 70 and 100 ml/kg of feed over 30 days while the highest RBC levels on day 60 were found in groups that were fed 50 and 70 ml/kg. Total white blood cell (WBC) levels were at the highest significant value (p < 0.05) in fish fed 70 ml/kg on days 30, 60, and 90 when compared with the control group. Hematocrit percentage (Htc) showed only a significant difference on day 30 and the highest level was observed in fish fed 70 ml/kg. Fish fed 50 and 70 ml/kg of feed had a significantly affected increase in lymphocyte, monocyte, eosinophil, basophile, and neutrophil levels but thrombocyte levels fluctuated. Based on our findings, we can assert that H. cordata leaf extract is suitable for application in the fingerling nursing step. This was especially seen during the first 30 days of the experiment, which showed that significantly higher values of growth indices could be achieved. Moreover, the extract should be looked at further in terms of its application for immune stimulation in fish, because different white blood cell types were increased by H. cordata leaf extract.