Morinda citrifolia L. (Noni) dietary supplementation ameliorates fluoride toxicity in the freshwater fish, Cyprinus carpio L.

Abstract

Fluoride is the organic and inorganic compound of the element fluorine, has detrimental effect to all animals including fish at higher concentration. Ground water with elevated concentration of fluoride is a major global problem including India. On the other hand, Morinda citrifolia (also called ‘Noni’ in Polynesia) is a medicinal plant, has antioxidative, anti-inflammatory and immunostimulatory properties. The ameliorating effect of M. citrifolia fruit extract dietary supplementation against fluoride induced toxicity on the growth performance, haematological parameters, and fluoride accumulation in the muscular tissue was investigated in the freshwater fish, Cyprinus carpio L. for 35 days in triplicate. One hundred and twenty acclimated C. carpio fingerlings were randomly allocated into five experimental groups (Groups I, II, III, IV and V) each with 24 fish divided into three replicates (eight fish/replicate). Group I (Control) and II (Toxic control or negative control) were provided with basal/control diet, whereas groups III, IV, and V were provided with 0.25% (2.5 g/kg), 0.50% (5.0 g/kg) and 0.75% (7.5 g/kg) M. citrifolia fruit extract supplemented diet respectively. All groups except for group I were exposed to 10% of the LC50 of fluoride. Selected growth and haematological parameters were estimated. The fluoride content in the muscular tissue of fish was also estimated following SPADNS method. Results revealed that exposure of sublethal concentration of fluoride significantly (P <0.05) reduced the growth performance and haematological parameters in Gr. II (toxic control) compared to the Gr. I (control). However, M. citrifolia dietary supplementation significantly (P <0.05) improved fluoride induced alteration of growth performance and haematological parameters of fish in the groups III, IV and V compared to Gr. II. Morinda citrifolia fruit extract dietary supplementation also significantly (P <0.05) decreased the accumulation fluoride in the muscular tissue of fish in groups III, IV and V compared to the Gr. II (toxic control). In conclusion, M. citrifolia dietary supplementation ameliorates the fluoride toxicity by preventing the accumulation of fluoride in the muscular tissue of the fish. The M. citrifolia dietary supplementation at 0.25% showed the best response, hence it is considered as the optimum dose.