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This study was conducted to determine whether the macroalgae Ulva papenfussi and Ulva nematoidea could be alternatives for preventing Litopenaeus vannamei vibriosis caused by the bacterium Vibrio parahaemolyticus. Phytochemical screening was performed on methanolic extracts to qualitatively determine the main groups of bioactive compounds, previous to an in vitro antibacterial test against V. parahaemolitycus. Phenols, polyphenols, flavonoids, and the high presence of carbohydrates were found in both macroalgae. U. papenfussi showed more presence of lipids and alkaloids than U. nematoidea. Macroalgae extracts prepared (v:v) with a 1:1 methanol: dichloromethane solvent was used for the in vitro test using the disc diffusion method (MDD). Filter paper discs impregnated with 1.0, 1.5, 2.0, 3.0, and 4.0 mg of the extracts showed antibacterial activity against V. Parahaemolitycus in a dose-dependent manner in both macroalgae. The inhibition zone varied significantly (p < 0.05) from 8.33 ± 0.12 to 11.41 ± 0.73 mm for 1 to 3 mg of extract levels, respectively. In conclusion, both macroalgae have antibacterial activity in their crude extracts against this bacteria. It is suggested to evaluate it as a feed additive for L. vannamei. This study is the first report on a phytochemical screening and antibacterial activity of these macroalgae against V. parahaemolyticus. [ABSTRACT FROM AUTHOR]

We observed the presence of follicular cells (FC) in the ovaries of Penaeus subtilis (n = 1198), which led us to classify the development of germ cells into six phases: oogonia, previtellogenic oocytes, primary and secondary vitellogenic oocytes, mature oocytes and atretic oocytes. The FC changes their shape according to the development of germ cells and showed a different distribution along the ovary, which allowed differentiating vitellogenic oocytes into primary and secondary. We also observed that the postovulatory follicles (POF) are composed of follicular cells. The presence of POF in penaeids ovaries is rarely reported, but allows the differentiation between spent and resting stages, commonly grouped in reproductive biology research. Furthermore, observation of ovarian lining was useful to differentiate immature females from females that had spawned at least once. Thus, ovarian development was classified into six stages: immature, early developing, advanced developing, ripe, spent and resting. The distribution and shape variations of FC, ovarian lining features and presence of POF were considered crucial for the classification of ovarian maturation stages. The methods developed here may improve estimates of their reproductive cycle, size at first maturity and spawning season, which are important variables in future studies of the reproductive dynamics. [ABSTRACT FROM AUTHOR]

ABSTRACT This study describes the larval development of the Venerid bivalve mollusc Anomalocardia brasiliana 'berbigao' under laboratory conditions. The clams were collected at Mangue Seco beach (Pernambuco, northeastern Brazil) and [...]

ABSTRACT The culture of the indigenous pink shrimp Farfantepenaeus brasiliensis was investigated in the Patos Lagoon estuary in southern Brazil. The study analyzed the effects of stocking density on growth [...]

Shrimp research has been focused on the development of feeds with minimal levels of fishmeal, as well as using alternative, lower cost protein sources. The study objective was to evaluate the performance of the Pacific white shrimp Penaeus vannamei fed with four different protein‐based extruded diets [plant‐based (AP), 8% poultry by‐product meal (PM8), 8% fishmeal (FM8) and 12% fishmeal (FM12)] while cultured in two independent trials with clear water and biofloc type systems. Additionally, the pellet durability index (PDI) and hardness of these diets were determined. Results from the clear water experiment showed that the shrimp fed with PM diet had the lowest final individual weight, biomass (g) and weight gain (g), and the poorest feed conversion ratio (FCR). It was observed that the shrimp fed with AP, FM8 and FM12 diets had significantly higher weight gain than shrimp offered the PM8 diet. Results from the biofloc experiment showed that shrimp fed with AP diet had the lowest biomass (g), weight gain (g) and thermal growth coefficient and the poorest FCR. No significant differences in survival rate were observed among the four diets in both experiments. The extruded diets showed high PDI when measured using the tumbling box and the Holmen tester. Additionally, the pellet hardness showed no significant differences among the four diets. The low inclusion of fishmeal, as well as the use of alternative protein sources in these diets, did not adversely affect the final weight, weight gain and percent weight gain of P. vannamei. [ABSTRACT FROM AUTHOR]