Abiotic and biotic stress alleviating effects of the medicinal and aromatic plant-derived product on striped catfish Pangasianodonhypophthalmus.

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.

Sources, distribution and risk assessment of polycyclic aromatic hydrocarbons in the mangrove sediments of Thane Creek, Maharashtra, India.

The sources, distribution and risk assessment of polycyclic aromatic hydrocarbons (PAHs) were investigated in the mangrove sediments of Trombay and Vashi, along the Thane Creek, Maharashtra, India, for a period of 6 months. The results showed that the concentration of Æ©15 PAHs ranged from 902.58 to 1643.60 and from 930.69 to 1158.30 ng g(-1) in Trombay and Vashi, respectively. Trombay showed significantly higher PAH concentration (p < 0.05) than Vashi. The four carcinogenic PAHs, (benzo(b)fluorathene, benzo(k)fluorathene, Indeno(1,2,3-cd)pyrene and dibenz(a,h)anthracene) accounted for maximum concentration of the total PAHs. Specific PAH diagnostic indices and the molecular index indicated the presence of both pyrolytic and petrogenic sources with the predominance of pyrolytic origin. A positive correlation (r = 0.736, p < 0.05) existed between the benzo(k)fluorathene level and total PAHs, suggesting the use of this compound as a potential molecular marker for PAH pollution in mangrove sediment. Assessments of potential environmental risks associated with PAHs in this study revealed that the sediment was moderately polluted with high molecular weight PAHs. The study reports the baseline data that can be used for regular monitoring of contamination level considering the heavy industrialization and urbanization along the creek and its coastal region.