Emiko Shinozaki Mendes

A multi-season survey for infectious myonecrosis in farmed shrimp, Litopenaeus vannamei, in Pernambuco, Brazil.

Infectious myonecrosis (IMN), caused by infectious myonecrosis virus (IMNV), is the disease of greatest impact on shrimp farming in the northeast region of Brazil. The occurrence of IMN remained restricted to northeastern Brazil until 2006, when its presence was also confirmed in Indonesia. To determine the occurrence and evolution of IMN in Litopenaeus vannamei farmed along the coast of the state of Pernambuco, Brazil, histopathological examinations were performed on 60 samples collected from four farms in both predominant seasons in the northeastern region: dry and wet seasons. Samples made up of ten specimens were collected monthly from each pond. Histopathological results were associated to wet-mount exams and rearing performance data. Lesions suggestive of IMN (coagulative necrosis, hemocytic infiltration in the musculature, ectopic spheroids in the lymphoid organ) were identified in all the farms, with a higher occurrence during the dry season. Longer rearing periods and higher stocking densities were the variables with the most significant influence (p<0.05) in the occurrence of IMN.

Coliform accumulation in Amphibalanus amphitrite (Darwin, 1854) (Cirripedia) and its use as an organic pollution bioindicator in the estuarine area of Recife, Pernambuco, Brazil

Samples of water and barnacles Amphibalanus amphitrite were collected from Recife, Brazil, to assess if it accumulates total (TC) and thermotolerant coliforms (TTC) related with sewage pollution. The Most Probable Number (MPN) values and the standard procedures for examination of shellfish were used. Comparatively with the water samples, the highest coliform values came from the barnacles, with TC values ranging from < 3.0 x 10(3) to > 2.4 x 10(6) MPN.g-1, and TTC ranging from > 2.4 x 10(3) to 2.9 x 10(5) MPN.g-1. Barnacles accumulate the TC Ewingella americana, and the TTC Escherichia coli, Enterobacter gergoviae, Enterobacter aerogenes, and Enterobacter sakazakii. The results provided an indication of the level of organic contamination at the sampling locations and that this species could be a good organic pollution bioindicator.

AVALIAÇÃO DE POTENCIAL PROBIÓTICO FRENTE À INFECÇÃO EXPERIMENTAL POR VÍBRIOS EM PÓS-LARVAS DE CAMARÃO MARINHO

Bacillus spp. have been used against diseases caused by bacteria that affect cultured shrimp, providing beneficial effects on the host shrimps by altering their microbial community, and improving zootechnical indexes. The objective of this work was to evaluate the effects of a diet supplemented with Bacillus cereus—a bacterium with probiotic potential—on post-larvae Litopenaeus vannamei shrimps grown in laboratory. The experiment lasted for fifteen days and consisted of six treatments—control (T1), probiotic (T2), Vibrio parahaemolyticus (VP) (T3), probiotic and VP (T4), V. alginolyticus (VA) (T5), and probiotic and VA (T6). The survival rate, weight gain, colonization capacity of the probiotic bacteria, pathogen count, and histopathological lesions were evaluated. There was no significant difference (p≥0.05) in survival between treatments. The groups with pathogens and without probiotics presented lower weight gain. The result of the Bacillus cereus count in the treatments T2, T4 and T6 were significantly different (p<0.05), the probiotic bacteria were more aggressive in competing for space and nutrients when compared to V. parahaemolyticus than when compared to V. alginolyticus. Animals fed with the probiotic presented lower counts of these pathogens than those fed without the probiotic (p<0.05). No histopathological lesions were found in the organs and tissues of the shrimps. Bacillus cereus showed a high colonizing capacity in post-larvae shrimps, causing a significant reduction of pathogens, probably by secreting antimicrobial substances and the competitive exclusion, which justifies their use as probiotic bacteria.

Hiperplasia em túnicas de artérias coronárias de beijupirás criados em sistema offshore

The coronary lesions have been reported in species of anadromous fish with similar characteristics as those observed in human atherosclerosis, but not in farmed fish without interference of reproductive patterns. This study aimed to describe coronary lesions in beijupira (Rachycentron canadum) farmed in an offshore system, in 54 specimens collected along an eight month cultivation period. Samples of heart tissue of fry and juveniles were subjected to histopathological analysis and transmission electron microscopy (TEM) for visualization of coronary lesions, the histology slides were stained using hematoxylin-eosin, periodic acid Schiffh, alcian blue, and reticulin of Gomori. Examinations performed by light microscopy showed arterial lesions characterized by hyperplasia of the intima and media tunics, respectively in 29.63% and 79.63 % of the animals, with reduced lumen. In TEM changes in the structure of the coronary endothelium and thickening of the basement membrane, proliferation of fibroblasts and collagen fibers, with subendothelial accumulation of lipid material, cellular debris adhering to the basement membrane and presence of pinocytotics vesicles and isolated lysosomes were observed. It has been found that the Rachycentron canadum fish species farmed in captivity develop arterial lesion of the chronic inflammatory degenerative type.