Microbiota associated with pacu Piaractus mesopotamicus larvae: live food and dietary probiotic effect

Abstract

Negative bacteria-larva interactions are known to cause low growth and survival rates in fish larviculture. Healthy microflora could increase the resistance of larvae against detrimental bacteria and inhibit growth of pathogenic microorganisms. Probiotic microorganisms are able to colonize the larvae gastrointestinal tract before the establishment of a native microflora provided by the environment. Probiotic dietary supplementation could change the host's intestinal microbiota and improve feed efficiency which influence the digestive processes. We will address in this study the role of first feeding for microbiota establishment of pacu Piaractus mesopotamicus. In addition, the morphophysiological development of digestive tract and early weaning in response to Bacillus spp. will be studied. Therefore, we will analyze the impact of live feed on the microbiota associated with pacu larvae. Additionally, we will analyze the effect of probiotic dietary supplementation with respect to weaning procedure, growth and survival, histology of the gastrointestinal tract, activity of digestive enzyme and microbial community in larvae. Thus, this study may indicate if live feed entail major changes to the composition of pacu larval microbiota. Moreover, our results will contribute to understand if diet is a good strategy for management of larval microbiota in aquaculture, and therefore if delivery of probiotics through live feed is the best strategy in larval stages. Further, this study may also produce relevant information to the culture of this and other fish species, as well as will provide alternatives to the use of medicines and antibiotics in aquaculture production. (AU)