Effects of dietary Bacillus subtilis and Shewanella algae in expression profile of immune-related genes from hemolymph of Litopenaeus vannamei challenged with Vibrio parahaemolyticus.

B. subtilis and S. algae effects in growth, survival and innate immunity were assessed on L. vannamei juveniles. During 60 days, shrimp were reared in three treatments: Bs, fed with 106 CFU of B. subtilis per gram of commercial feed, Sa, fed with 106 CFU of S. algae per gram of commercial feed and Control (without bacterial addition). Then, the animals were subjected to a V. parahaemolyticus challenge. For this purpose, four treatments were established: Control (shrimp not submitted to probiotic treatments), Vibrio (Vibrio challenged shrimp), Vibrio + Bs (Bs challenged shrimp) and Vibrio + Sa (Sa challenged shrimp). Shrimp hemolymph was sampled 45-days after rearing and 24 h post-challenge for quantification of prophenoloxidase (proPO), lipopolysaccharide and ß-1,3-glucan-binding protein (LGBP) and hemocyanin (HEM) transcripts by qPCR. Moreover, shrimp final weight and survival were also verified. B. subtilis administration enhanced shrimp growth and improved proPO, LGBP and HEM expression levels before and after challenge. After 60-days of feeding, Sa final weight was higher than the Control, whereas Vibrio + Sa cumulative mortality after 48 h of Vibrio challenge was lower than Vibrio group. These results could be correlated with the proPO and LGBP up regulation in Vibrio + Sa compared to Vibrio group, protecting L. vannamei from the bacterial infection. Together, these results suggest the probiotic potential of B. subtilis e S. algae in the modulation of immune-related genes as a tool to control V. parahaemolyticus infection inside shrimp.

Technical efficiency analysis of marine shrimp farming (Litopenaeus vannamei) in biofloc and conventional systems: A case study in northeastern Brazil.

Shrimp farming has a great ecological, economic, and social importance in northeastern Brazil. Although the conventional farming system is widely used, biofloc technology (BFT) system has been developed to reduce environmental impacts and optimizing the production. Thus,the present study evaluated the technical efficiency of production cycles of Litopenaeus vannamei in conventional and BFT systems.We analyzed 48 production cycles in the conventional system in 2013 and 2014 and 9 cycles in the BFT system in 2014 through data envelopment analysis (DEA). The inputs corresponded to the population density (post-larvae m-2), amount of feed (kg ha-1 cycle-1), labor (man ha-1) and power supply (HP ha-1), whereas the yield (kg ha-1 cycle-1) was considered the output. The results indicated four production cycles (7.0%) technically efficient, three in the conventional system and one in the BFT. By comparing the productive systems, there was significant difference in their mean scores of technical efficiency. There was a greater influence of the management inefficiency on the conventional system, while the production scale reduced the average scores of technical efficiency in the BFT system. These results may help to improve the development of sustainable L. vannamei farming in both systems by reducing waste and increasing profits.

Coliform risk assessment through use of the clam Anomalocardia brasiliana as animal sentinel for shellfish harvesting areas in Brazil's northeast.

Outbreaks of food-borne diseases related to consumption of contaminated shellfish have been reported in many countries, but not in Brazil, possibly due to deficient reporting. Here we investigated the suitability of the clam Anomalocardia brasiliana as an animal sentinel for coliform monitoring in shellfish harvesting areas of Brazil's northeast. Samples of shellfish meats (40 clams per sample; n = 8 per collection) were collected at random from April 2009 through March 2010 in the bay area of Mangue Seco (state of Pernambuco). The numbers of thermotolerant coliforms were analyzed through the most probable number technique, and these contamination levels were tentatively correlated with the precipitation recorded on the day of sampling or 24 to 48 h beforehand. A. brasiliana shellfish meats from local retail shops (250 g per sample/ n = 3 per market) sold frozen were also investigated from August 2010 through June 2011. We found that the highest coliform contamination levels were correlated with recent rainfall events, limited to 24 h before sampling. However, irrespective of the rainfall level, the mean contamination above the Brazilian legal threshold of < 3 × 10(2) MPN/ 100 g for shellfish harvesting areas ranged from 18.7 to 93.7 % of samples analyzed monthly. Additionally, a large number of samples obtained from retail shops were also highly contaminated by coliforms during rainy periods, and therefore were not proper for human consumption. We conclude that A. brasiliana can be successfully used to monitor the contamination levels of coliforms in shellfish harvesting areas in Brazil's northeast coast.