Aquatic environmental risk assessment of chitosan/silver, copper and carbon nanotube nanocomposites as antimicrobial agents.

Despite the potential antimicrobial and water purification benefits of chitosan-based nanocomposites, there are growing concerns regarding the hazards of leached nanoparticles (NPs) to the in-contact circumference. The antibacterial performance of the nanocomposites of chitosan with silver and copper NPs and carbon nanotubes was assessed with an emphasis on their impact on fish health. The minimal inhibitory concentrations of each preparation and the growth curves of Aeromonas hydrophila exposed to different nanocomposites were measured. Five groups of Oreochromis niloticus were exposed to chitosan nanocomposites for three weeks. A combination of a low concentration of the NPs in the chitosan matrix improved their antimicrobial properties. However, aqueous exposure to these materials still had hazardous effects on fish health. Experimental groups of O. niloticus exposed to these nanocomposites exhibited oxidative stress, tissue DNA fragmentation and higher expression of pro-inflammatory and immune-related genes such as TNF-α and IL1ß. Various pathological tissue alterations were observed in gills, liver, spleen and intestine. Exposure to some of the prepared nanocomposites led to significant DNA damage in hepatic cells with a marked increase in the apoptotic index.

Preparation and immunological evaluation of inactivated avian influenza virus vaccine encapsulated in chitosan nanoparticles.

Efficacy maximization of inactivated avian influenza vaccine using safe adjuvants was investigated. Chitosan nanoparticles were prepared by ionic gelation method with average size of 150 nm and their Zeta potential was 11.5 mV. After encapsulation of avian influenza vaccine, the average size was 397 nm and Zeta potential was 4.29 mV. The highest HI antibody titer results were shown in chicken group vaccinated with inactivated avian influenza virus AIV-chitosan followed by the group vaccinated with inactivated AIV-chitosan nanoparticles then the group vaccinated with oil inactivated AIV vaccine, on using chicken antigen at 2 weeks post second vaccination. Upon using duck antigen, the highest HI antibody titers were shown in chicken group vaccinated with inactivated AIV oil emulsion vaccine followed by chicken group vaccinated with AIV-chitosan nanoparticles then the group vaccinated with AIV-chitosan. Chicken in the group vaccinated with AIV-chitosan nanoparticles induced the best results of lymphocyte proliferation assay. The results of phagocytic activity percentage and phagocytic index of AIV-chitosan nanoparticles and AIV-chitosan groups at 3 days post first vaccination were increased significantly in comparison with other groups, whereas at 14 days post first vaccination, group vaccinated with AIV-chitosan nanoparticles showed significant increase in phagocytic activity percentage and phagocytic index.

Assessment of the immune-modulatory and antimicrobial effects of dietary chitosan on Nile tilapia (Oreochrmis niloticus) with special emphasis to its bio-remediating impacts.

Fish, pathogen and environment are three counterparts who are sharing the same circle of life. To keep fish up to their optimal health, environment should be competently improved and pathogen count/virulence should be seized. Using of bioactive immunostimulants to achieve these objectives is the hypothesis under assessment. Thus, the present study was performed to evaluate the use of shrimp shells derived chitosan as an immunostimulant as well as preventive regime against Aeromonas hydrophila infection of Nile tilapia and to assess its antibacterial/aquatic bio-remediating effects. Results achieved by feeding 1% chitosan as preventive/therapeutic regimes have revealed a remarkably enhanced several innate immunological parameters (e.g., Phagocytic activity/index, NBT, Lysozyme activity and ACH50), increased resistance against A. hydrophila and strikingly improved water quality compared to the 0.5 and 2% chitosan containing diets. Conclusively, experimental results suggest the commercial usage of chitosan as an efficient immunostimulant and bio-remediating agent in aquaculture.