Utilização do probiótico Lactococcus lactis na larvicultura do jundiá Rhamdia quelen

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências Agrárias, Programa de Pós-Graduação em Aquicultura, Florianópolis, 2017.

Access type:openAccess
Publication Date:2017
Main Author: Spanghero, Emília Carolina Alencar de Medeiros
Advisor: Zaniboni Filho, Evoy
Co-advisor: Mouriño, José Luiz Pedreira
Document type: Master thesis
Online Access:https://repositorio.ufsc.br/handle/123456789/185543
English abstract:Abstract : Aquaculture is the main source of production to increase the supply of fish, and the Rhamdia quelen jundiá is included in this context, as it stands out for its great economic importance for the southern region of Brazil. It is widely used in fish farms, being considered a very promising species for cultivation. However there are some obstacles in your larviculture. A strategy to increase its production may come through the use of healthier larvae, which present better survival and satisfactory growth, from the use of probiotic supplemented in the feeding. The objective of this study was to evaluate the effects of the inclusion of the probiotic strain Lactococcus lactis on the larvae of the jundiá Rhamdia quelen. The larvae were distributed in boxes with 10 L (20 larva.L-1) in water recirculation system coupled with biological filter, in salinized water (2 g.L-1) and controlled temperature. Each experimental unit received constant aeration and was submitted to the photoperiod of 12 h. The fish were fed four times daily with the daily equivalent of 20% of live biomass for 21 days, being submitted to three treatments: 1- Ration (R); 2- Ration + Lactococcus lactis (RP) (bacterium + MRS culture medium); 3- Ration + supernatant of the Lactococcus lactis (RS) culture. At the end of the experimental period, the zootechnical performance, resistance to stress by exposure to saline water and air, and possible morphostructural changes of intestinal tract and intestinal microbiota were evaluated. When exposed to resistance tests, there was no difference between the treatments (p> 0.05) in relation to the survival of fish submitted to stressors. There was histomorphometric similarity of the intestines of the fish (p> 0.05) submitted to the different alimentary treatments. The larvae supplemented with probiotic in their diets presented higher survival (p <0.05) when compared to the other treatments. Additionally, larvae receiving a diet supplemented with probiotic L. lactis had intestines with lower vibrios colonization and higher concentration of lactic acid bacteria. The added diet of L. lactis was able to colonize the intestinal tract of jundia larvae, resulting in increased survival and induced reduction in growth of unwanted bacterial groups.