양식 넙치용 습사료의 친환경적 개선을 위한 키토산 코팅제의 개발

Most aquacultural farms have been using moist pellet (MP) feeds for growing cultured fish. However MP feeds have several serious problems, because of weak bind capacity of MP feed itself, including rapid collapse of the formation in salt water, feed loss, frequent occurrence of pathogenic fish diseases and environmental pollution. In order to overcome this situation in the farms we tried to coat MP feeds with natural biopolymer solutions to enhance binding capacity of MP feeds. Chitosan was the most effective biopolymer which improved suppression rate of collapse in salt water and floating rate of MP feeds on the surface of salt water. In addition chitosan-agar complexed bipolymer increased the coating efficiency by about 50% in suppression rate of MP feed collapse in salt water, compared to non-coated MP feeds. Besides coating MP feeds with chitosan-based biopolymer protected the growth of pathogenic fish bacteria such as vibrio spp., Edwardia tarda and streptococcus spp. separated from Japanese flounder fish and increased oxidation stability against rancidity of the feeds during five days of storage. From the results chitosan-based biopolymer might be an effective coating material for environmental-friendly improvement of fish MP feeds in aquacultural farms.