Search

The presence of diseases caused by virus and bacteria pose a threat to the capture and commercialization of shrimp, and may cause significant economic damage. Nocturnal monthly sampling were conducted to detect the presence of IHHNV, WSSV, and NHP in San Andres Lagoon in Tamaulipas, Mexico, an important coastal ecosystem due to its shrimp fishery and the existence of shrimp farms in the area. Polymerase chain reaction (PCR) analysis in the shrimp tissue did not detect the presence of IHHNV, however, WSSV was detected, as well as NHP during July and August, when low salinities and high temperatures were recorded. [ABSTRACT FROM AUTHOR]

Shrimp is one of the main aquaculture species in the world. Different viruses affect them, which causes serious mortality to economically important species, such as Penaeus monodon, Litopenaeus vannamei and L. stylirostris, among others. White spot syndrome virus or WSSV is a highly lethal, stress-dependent virus, which belongs to the family Nimaviridae, genus Whispovirus. Three WSSV virus isolates were first detected in 1992 in Thailand, Taiwan and China. Later, a fourth isolate of the virus was detected in the Americas in 1999. This virus has a large circular double-stranded DNA genome with different sizes (292.9–307.2 kb), where the diverse isolates show differences in virulence. This virus infects a wide range of aquatic crustaceans by vertical and horizontal transmission, with different mortality results. The spread of infection between regions may be due to infected shrimp and carriers such as other crustaceans, seabirds, aquatic arthropods or other vectors. The aim of this work is to describe the current knowledge on the status, transmission, pathology, isolation, control and genomic characteristics of WSSV. [ABSTRACT FROM AUTHOR]

Shrimp aquaculture is an important industry that experiences significant losses fromVibriospecies, especially at the larval and juvenile stages. Proteinaceous virulence factors, including alkaline proteases, metalloproteases, cysteine proteases and alkaline serine proteases, have been identified as important elements inVibriopathogenesis. This review summarizes current knowledge regarding the principal pathogenicVibriospecies in shrimp, with emphasis on relevant exotoxins and their modes of action, principal characteristics and molecular database. This pathogenic factors and their relation with other molecules produced by microorganisms may be help to understand the virulence mechanisms present inVibriostrain. [ABSTRACT FROM AUTHOR]

Baker''s yeast Saccharomyces cerevisiae is a potential supplement in shrimp feeds, but there are few data on yeast survival after feed manufacturing processes. Dry, active yeast cells, agglomerated in spheres of different sizes (100–200 and 800–1600 μm) were incorporated into feeds processed by a commercial pellet mill or in the laboratory using a meat grinder, in order to check their resistance to the process, storage, immersion in seawater, and their effect on the pellet stability in seawater. Total counts (cells seen alive by microscopy evaluation) and viable yeast counts (colony forming units on malt agar plates) were determined in feed samples at different stages of the process. Pelleting had no significant effect on total yeast counts but decreased the viable yeast numbers about 10-fold. The laboratory process was more destructive with a 105-fold decrease for both total and viable yeast counts. Immersing the feed pellets in seawater further reduced the yeast number but only by less than 10-fold. Fine yeast spheres (<200 μm) had a slightly better overall resistance and survival than large yeast spheres (>800 μm). Pellet stability in seawater was not affected by the inclusion of the yeast agglomerates. [Copyright &y& Elsevier]