Probiotic bacteria may prevent haemorrhagic septicaemia by maturing intestinal host defences in Brazilian native surubins

Abstract

The farming of hybrid surubins in Brazil has been affected by bacterial diseases. To avoid this problem, the development of prophylactics such as probiotics has proved to be a promising tool against bacterial outbreaks. This study evaluated the dietary supplementation with lactic acid bacterium Weissella cibaria and its probiotic action in the intestinal tract focusing the hemato-immunological parameters, histology and electron microscopy. A total of 96 fish were maintained in a recirculation system and divided into 12 tanks, two treatments (supplemented and unsupplemented fish) and six replicates. Fish were fed supplemented commercial diet with W. cibaria for a period of 45 days, and the unsupplemented fish were with commercial feed without probiotic. The numbers of red blood cells, thrombocytes and lymphocytes were higher in supplemented fish after 45 days (P < 0.05). The percentage of phagocytosis, the agglutination titre and the total immunoglobulin concentration were higher in fish fed probiotic. Fish fed supplemented diet presented increased length and width of the intestinal villi, the number of goblet cells and villi's perimeter. The probiotic W. cibaria was capable of colonizing and benefitting the surubins' gastrointestinal tracts, improving intestinal health and the hemato-immunological parameters of fish.