Presently, the shrimp consumers are afraid of the antibiotic residue problem. Because, the farmer lack the knowledge to use the antibiotics. Therefore, the by convincing exporter shrimp and the farmers were loss a lot of money. Thai government is urgently solving this problem, the farmer to use the natural products instead of the antibiotics. But the farmers are no response. Because of, the most important bacterial disease in shrimp is vibriosis (Karunasagar, et. al. 1994). The farmer used the antibiotics to kill or prevent the Vibrio spp. However,they know some natural products that can be use to control bacteria. Razdan and Pettersson (1994) reported chitosan could react with the cell wall and reduce the growth of bacteria. The chitosan is produced from chitin which is extracted from crab and shrimp shell (Roberts, 1992). Chitosan is a non-toxic, biocompatible and biodegradable natural polymer. The food, drugs, and cosmetic industry use the chitosan in a composition of their products. Therefore, chitosan should be safe for use to stop the bacterial diseases of shrimp.
The objective of this study was to