ABSTRACT
Intensification of aquaculture production leads to abiotic and biotic stresses, which are further induced by the impact of climate change. Thus, it is important to explore a combined strategy to alleviate multiple stresses in fish. In the present investigation, the removal of nitrogenous metabolites from aquaponics water was studied using products derived from five different locally available medicinal and aromatic plants (MAPs) namely banana stem (Musa Accuminata), Aloe vera, Mint (Minata sepicata), Indian beech/Pongameoil-tree/Karanj (Pongamia pinnatum), and Coat Button/Mexican daisy/Dagadipala (Tridax procrumbens) in the batch experiment for 24 h. A reduction of 91-94% in the ammonia level and 75-80% removal of nitrite-N in the treatments with products derived from mint, banana stem, and aloe vera has been observed. Mint product was also found to be bactericidal against fish pathogenic bacteria. Based on this dual function of mint, further study was conducted under wet-lab conditions to evaluate the possible protective role of the mint-based product in dry powder form against abiotic stresses caused by nitrogenous toxicants for 24 h and 45 days multiple stresses caused by nitrogenous toxicants in freshwater stocked with eight fingerlings of Pangasianodon hypophthalmus of the initial weight of 8 ± 0.5g for 24 h and 8.82 ± 0.75g for 45 days. The results revealed that mint-derived plant product has better anti-stress properties in terms of their bioremediation effectiveness in lowering ammonia and nitrite. Mint also improved the fish growth performance with better physiological responses and anti-oxidative status and reduced the cellular metabolic stress in fish reared under ammonia, as further indicated by reduced oxidative stress parameters, and tissue biochemical indices. Overall, mint showed its main properties as a growth promoter, and immune enhancer, where this medicinal plant product acts as a bioremediation and antibacterial agent to the host immune system. This has potential applications in the environmental and health management of aquaculture.
