Effects of chitosan and its derivative added to water on immunological enhancement and disease control.

BACKGROUND: An immune system is a system of biological structures and processes within an organism that protects against diseases by identifying and killing pathogens and tumor cells. Development of novel natural immune enhancers is an urgent issue. METHODS: In experiment 1, Newcastle disease antibody titer, levels of IL-6, IL-10 and IFN-γ, and changes in CD3(+), CD4(+) and CD8(+) cells were analyzed. In experiment 2, diarrhea, respiratory symptoms and mortality of broilers were measured. RESULTS: In experiment 1, the results showed that the immune response, such as Newcastle disease antibody and CD4(+) T cells, would be significantly activated by feeding with chitosan and its derivative during 27 days. In experiment 2, the results demonstrated that diarrhea, respiratory symptoms and the mortality of the commercial medicine treatment group were decreased, with infection days increased. However, the mortality of broilers was significantly decreased, while feed intake and weight gain of the birds were significantly increased in the group treated with chitosan and its derivative as compared with other groups. CONCLUSION: Chitosan and its derivative have strong potential in immune enhancement and disease control, and can be used as a feed additive.

Synthesis and characterization of collagen/hyaluronan/chitosan composite sponges for potential biomedical applications.

Cells, scaffolds and growth factors are three main components of a tissue-engineered construct. Collagen type I, a major protein of the extracellular matrix (ECM) in mammals, is a suitable scaffold material for regeneration. Another important constituent of the ECM, hyaluronic acid (hyaluronan, HA), has been used for medical purposes due to its hydrogel properties and biodegradability. Chitosan is a linear polysaccharide comprised of beta1- to beta4-linked d-glucosamine residues, and its potential as a biomaterial is based on its cationic nature and high charge density in solution. This study was conducted to evaluate the characteristics of scaffolds composed of different ratios of type I comb collagen and chitosan with added HA in order to obtain the optimum conditions for the manufacture of collagen-hyaluronan-chitosan (Col-HA-Ch; comprising collagen, HA and chitosan mixed in different ratios: 10:1:0, Col10HACh0; 9:1:1, Col9HACh1; 8:1:2, Col8HACh2; 7:1:3, Col7HACh3; 6:1:4, Col6HACh4; and 5:1:5, Col5HACh5) composite porous scaffolds. Microstructural observation of the composite scaffolds was performed using scanning electron microscopy. The mean pore diameters ranged from 120 to 182microm and decreased as the chitosan composition increased. All scaffolds showed high pore interconnectivity. Swelling ratio measurements showed that all specimens could bind 35- to 40-fold of physiological fluid and still maintain their form and stability. For tensile strength, the optimal ratio of collagen and chitosan was 9:1. Thermal stability was investigated using a differential scanning calorimeter and showed that Col5HACh5 and Col6HACh4 were significantly more stable than the other groups. In enzymatic sensitivity, a steady increase in the biostability of the scaffolds was achieved as the chitosan concentration was increased. In biocompatibility testing, the proliferation of the fibroblasts cultured in Co-HA-Ch tri-copolymer scaffolds was high. Overall, we observed the 9:1:1 mixing ratio of collagen, hyaluronan and chitosan to be optimal for the manufacture of complex scaffolds. Furthermore, Col-HA-Ch tri-polymer scaffolds, especially Col9HACh1, could be developed as a suitable scaffold material for tissue engineering applications.