Make your own free website on Tripod.com

Aquaculture Vol. 164 (1-4) pp. 337-349
Mortalities of pond-cultured juvenile shrimp, Penaeus monodon, associated with dominance of luminescent vibrios in the rearing environment
a C.R. Lavilla-Pitogo
a E.M. Leaño
a M.G. Paner
a , Aquaculture Department, Southeast Asian Fisheries Development Center, , Tigbauan 5021, Iloilo, Philippines
Abstract:    Severe mortalities due to luminescent vibrios occurred in pond-cultured Penaeus monodon juveniles particularly in the first 45 days of culture. Luminescent vibriosis epizootics led to reduced shrimp production due to mortalities and slow growth of affected stocks. Monitoring of bacterial population in the rearing water of several ponds was conducted from the time the ponds were flooded with water until 60 days of culture to understand the course of infection. Results showed that the occurrence of mortalities was preceded by a shift of the bacterial profile of the rearing water in infected ponds, notably the dominance of luminescent vibrios. Comparison of bacterial load in the rearing water and water source (river or open sea) showed elevated luminescent Vibrio counts in the former at 12 days to 3 weeks after initial entry of water. Histopathology of affected shrimps showed the hepatopancreas as the target organ of infection where severe inflammatory responses in the intertubular sinuses were seen. © 1998 Elsevier Science B.V. All rights reserved.


Aquaculture Vol. 164 (1-4) pp. 351-358
Control of luminous Vibrio species in penaeid aquaculture ponds

a D.J.W. Moriarty
a , Department of Chemical Engineering, The University of Queensland, , Qld 4072, Australia
Abstract:    A crisis has arisen in the prawn industry in many regions with the onset of disease, with Vibrio spp. being important major causal factors. The value of adding selected strains of Bacillus as probiotic bacteria to control the Vibrio is shown by comparing farms in Indonesia using the same water sources, which contained luminous Vibrio strains. The farms that did not use the Bacillus cultures experienced almost complete failure in all ponds, with luminescent Vibrio disease killing prawns before 80 days of culture were reached. In contrast, a farm using the probiotics was culturing prawns for over 160 days without problems, by using Bacillus at abundances of about 1×104 to 1×105/ml. The bacterial species composition was different in the pond water on the two farms and demonstrates that it is possible to change bacterial species composition and improve prawn production in large water bodies. Vibrio numbers, especially luminous Vibrio numbers were low in ponds where a large abundance of specially selected Bacillus species was maintained in the water column. Vibrio numbers were also low in sediments and no luminous Vibrio occurred in sediments where the probiotic Bacillus were used. © 1998 Elsevier Science B.V. All rights reserved.