Studies on the control of pathogenic Aeromonas hydrophila in crystal red shrimp (Caridina logemanni) using lactic acid bacteria (Pediococcus acidilactici)

• Main Authors: Chen, Guan-Xuan, 陳冠軒
• Other Authors: Lee, Kuo-Kau
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/7q5x94

碩士 === 國立臺灣海洋大學 === 水產養殖學系 === 106 === This study aimed to investigate bacterial disease of ornamental shrimp, Caridina logemanni, which occured during stress phases due to false husbandry and acclimation to environmental changes caused by transportation. We attempted to feed Pediococcus acidilactici orally to be an intestinal probiotic to regulate immunity of the host and to reduce the risk of infection by a common pathogen, Aeromonas hydrophila. Shrimps used in this study were purchased from different breeders all over Taiwan and the bacterial pathogens were isolated from moribound shrimps during husbandry and after transportation. There were several strains of A. hydrophila identified using biochemical tests, 16S rRNA sequencing and histological sections, and the pathogenicity of the bacteria was evaluated by immersion challenge tests. Histopathological observation revealed that the foregut, midgut gland and midgut of the shrimps infected by A. hydrophila exhibiting aggregation of bacterial cells, a large amount of necrotic epithelial cells stripping and accompanied with different degrees of inflammatory responses. Two strains of lactic acids bacteria, P. acidilactici, were confirmed by the identification methods as mentioned above. Followed by employing the in-vitro co-culture test with A. hydrophila and supplementing the bacteria with feed to shrimps to evaluate the potential of using these bacteria as the probiotics. The results showed that P. acidilactici strain La0707 had better bacteriostatic abilities than strain Lp0709. Shrimps used the feed supplemented with P. acidilactici strain La0707 1010 CFU/g continuously in 3 weeks, had the relative percentage survival up to 75%. From the present results, it is suggested not to use frozen blood worm as food for shrimps since it maybe contaminated with A. hydrophila. The use of P. acidilactici as probiotics may prevent crystal red shrimp from infection caused by A. hydrophila.