A 30 days trial was conducted to evaluate the colour enhancement in sword tail through the supplementation of pigment produced from the bacteria in their diets. Sword tail fishes (1.2 ± 0.01g) were stocked in 70 litre crates at the rate of 20nos / crates in triplicates. Fishes fed with normal diet served as control (C) and diet supplemented with pigment (50mg/kg) isolated from the bacteria Exiguobacterium profundum (T1), Chryseobacterium joostei (T2), Staphylococcus pasteuri (T3), Staphylococcus arlettae (T4) served as treatments. The characteristic features of the pigments isolated from the four different bacteria were checked for antibacterial, total antioxidant activity and the reductive ability. E. profundum showed highest reductive (0.131) and antioxidant ability (406.5µg) whereas S. arletta and C. joostei showed higher antimicrobial activity (zone of inhibition – 30mm) against Aeromonas hydrophila. Significant difference was observed in water quality parameters except temperature between the experimental groups.Growth parameters showed significant difference between control and treatment. Highest carotenoid concentration (22.8µg/g) was found in fishes fed with pigments extracted from Staphylococcus pasteuri compared to other experimental groups. The present study proved the incorporation of bacterial pigments in the diets of sword tail enhanced the total carotenoid concentration.
Keywords:Pigments, Carotenoids, Sword tail and Colouration