A Phytobiotic Supersupplement From Murraya koenigii Improves Growth, Physiological Health, Skin Colour and Pattern in a Wild Ornamental Fish (Oreichthys crenuchoides) Under Captivity.

Ornamental fish sector is one of the fastest growing industries in the world with an estimated market value of 18-20 billion USD. Despite its global economic significance, it suffers from several issues notably, high-cost carotenoids, inadequate seed production and antimicrobial resistance (AMR). The existence of multifaceted problems needs an integrated multifunctional solution. The phytobiotics of Murraya koenigii (PMK), also called as curry leaf is known for its diverse bioactive compounds with rich flavonoids and carotenoids, and can be a silver bullet in dealing with the multidimensional issues in ornamental fish sector. The multifunctionality of the selected phytobiotics was assessed in drapefin barb, Oreichthys crenuchoides which is known for its non-chromatic nature with prominent reticulate melanin patterns. The PMK was administered orally at 0, 5, 10, 15 and 20 g/kg diet for 60 days. At the end of the trial, a significant difference was noted in the growth performance and feed utilisation efficiency in PMK-administered groups. The protease and lipase activities were increased significantly by the action of PMK, with the highest enzyme activity recorded at 5 g/kg group and the amylase activity was dropped in all PMK groups, facilitating an improved nutrient assimilation. The PMK regulated liver health, which was evident by the declined levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) activities in the liver and muscle. Further, haematological profile reflected the enhancement of aerobic metabolism and immunity by PMK. PMK also exhibited antimicrobial activity against selected pathogens. Despite the carotenoid content and mild greenish-yellow tinge on the skin, no significant skin colour changes were observed in chromaticity analysis. Instead, the reticulate patterns in O. crenuchoides became prominent due to the rich flavonoid content in PMK. Finally, the performance index and integrated biomarker response (IBR) index pointed out that 10 g/kg PMK as an effective dose of administration to O. crenuchoides considering its efficacy.