## 1 Introduction  
The white shrimp (_Litopenaeus vannamei_) is a widely cultured crustacean in the Pacific Ocean and is considered one of the dominant shellfish in world aquaculture with a global production of 300 metric tons [1; 2; 3; 4; 5; 6; 7]. The culture of _Litopenaeus vannamei_ (_L. vannamei_) is widely extended due its adaptability to different environmental conditions. Currently, several factors could threaten the production of _L. vannamei_: (1) the culture expansion has a negative impact on the environment, caused by farm effluents, (2) the high density during production has increased disease outbreaks in ponds and (3) emergence of antibiotic resistant pathogens given the continual use of these compounds during the culture [3; 4; 8; 9].  
One of the strategies used to improve the production in _L. vannamei_, is microbiome manipulation through nutritional management or by the inclusion of probiotics. In this sense, the microorganisms that inhabit the host are capable of producing digestible molecules that improve growth, health status, life-span and the resistance to biotic and abiotic factors in different of shellfish species [2; 9; 10; 11; 12]. The digestive functions in several species of decapods are performed by the hepatopancreas; in this organ the interaction among bacteria and the host allows the absorption of different types of substrates [3; 4; 10; 12; 13; 14].  
The function of the microbiome has been largely unknown, recent advances using next generation sequencing techniques along with function prediction software have allowed visualization of some of the complex trophic networks between the host organism and the microbiome [15; 16; 17; 18]. Previous studies of Peneids have focused on the microbiome composition in different stages of development, where the phyla _Proteobacteria_, _Bacteroidetes_, _Firmicutes_ and _Actinobacteria_ were in high abundance throughout all the developmental stages of _L. vannamei_[2; 3; 4; 10; 19]. In this sense, changes in the microbiome structure have been reported during _L. vannamei_ culture, where the presence of the _Commonadaceae_ family appeared when live feed was provided [2].  
Other type of studies in _L. vannamei_ have focused on the influence of probiotics in growth variables [20; 21], physiological response [22], nutritional aspects [23], in the transcript profile in different tissues and in the response to different viral pathogens [4; 6; 24]. All the aforementioned studies were able to identify how the development, health status and the culture conditions influence the microbiome composition and the gene expression in _L. vannamei_. Although the information regarding the microbiome function in _L. vannamei_ is reduced, there is only one report on this species which was performed in the hepatopancreas of adult individuals of _L. vannamei_ in culture conditions [25] where the presence of host and microbiome transcripts were related to the nutrient uptake and the response to abiotic and biotic stress.  
Given that the microbiome is highly dynamic, it is important to elucidate its role during different developmental stages in _L. vannamei_, in order to identify how the conditions of each stage of development shapes the microbial communities and how these communities interact with host transcripts. The objective of the present study was to determine the role of the metabolically active bacterial communities during the development of _L. vannamei_ in larval, juvenile and adult stages. This study represents the first report regarding the functional role of the microorganisms and the possible interactions during the development of _L. vannamei_.