Bacterial Population in Intestines of Litopenaeus vannamei Fed Different Probiotics or Probiotic Supernatant

Abstract

The interactions of microbiota in the gut play an important role in promoting or maintaining the health of hosts. In this study, in order to investigate and compare the effects of dietary supplementation with HC-2 (HC-2), NRW-2, or the bacteria-free supernatant of a HC-2 culture on the bacterial composition of , Illumina sequencing of the V1-V2 region of the 16S rRNA gene was used. The results showed that unique species exclusively existed in specific dietary groups, and the abundance of Actinobacteria was significantly increased in the intestinal bacterial community of shrimp fed with the bacteria-free supernatant of an HC-2 culture compared with the control. In addition, the histology of intestines of the shrimp from the four dietary groups was also described, but no obvious improvements in the intestinal histology were observed. The findings in this work will help to promote the understanding of the roles of intestinal bacteria in shrimps when fed with probiotics or probiotic supernatant.

Effect of mannan oligosaccharides on the microbiota and productivity parameters of Litopenaeus vannamei shrimp under intensive cultivation in Ecuador

“…The promotion of changes in the composition of the intestinal microbiota is a key component of the case for using MOS as prebiotics, but this aspect has also been one of the least developed. The composition of the microbiota of shrimp under control conditions is consistent with previous research on this species, agreeing that Proteobacteria is the dominant phylum, with relative abundance levels between 28 and 70% [44][45][46][47][48][53][54][55][56][57] . Other phyla showing high abundance under control conditions were Bacteroidetes (22%) and Actinobacteria (11%), whose values matched those in some of the previous studies; however, overall, those studies showed variable relative abundance levels.…”

“…The effect of the inclusion of MOS on the microbiota of shrimp is reflected in the relative abundance at the phylum level, with the predominance of Actinobacteria over Proteobacteria and without any previous background about the displacement of the phylum Proteobacteria by the phylum Actinobacteria in association with a dietary intervention in this species. However, using NGS, it has been reported for L. vannamei that dietary supplementation with the supernatant from the bacterial strain HC-2 46 or with cornstarch as a source of carbohydrates 45 leads to changes associated with increases in Actinobacteria and Firmicutes, respectively, without affecting the position of Proteobacteria as the dominant phylum.…”

“…For cultivated crustaceans such as L. vannamei, information on the functionality and structuring of microbiota is very limited. Latterly, advances in NGS have allowed develop research on crustaceans microbiota, as recently addressed in some studies [44][45][46][47][48] . These investigations have been based on modulating the L. vannamei microbiota through nutritional challenges in laboratory conditions.…”

Exploring the influence of surface proteins on probiotic activity of Lactobacillus pentosus HC-2 in Litopenaeus vannamei midgut via Label-free quantitative proteomic analysis

“…In the present study, the changes in the intestinal microvilli and the folding of the digestive epithelium varied between dietary groups, and obvious improvement in intestinal histology was observed after shrimp fed with the normal probiotic HC-2, and the intestinal tissue was not damaged after the shrimp were challenged by V. parahaemolyticus E1. These results are similar to the findings of Merrifield et al (2010) [33], who found that Pediococcus acidilactici - fed fish had significantly longer microvilli than other groups of fish, but are contrary to the findings of Sha et al (2016) [20], who reported that dietary HC-2 didn’t improve the intestinal morphology of L. vannamei . These differently phenomena may be attributable to the bacteria concentration used in the dietary is too low (10 7 CFU/g) than in this work (5×10 8 CFU/g), which hinder the HC-2 to be the dominant microflora in the shrimp intestines to improve the intestinal morphology.…”

“…The histology determine was carried out as described in Sha et al (2016) [20]. Five shrimps were freely selected from each treatment group upon termination of the feeding and challenge experiments and sampled the midguts to dissect and fix (60% absolute ethanol, 30% trichloromethane, 10% acetic acid) for 19 h. Following, the fixed tissues were dehydrated in ascending concentrations of alcohol (70, 80, 95, and 100%), cleared in toluene, embedded in paraffin, and sectioned at 10 μ m with a rotary microtome.…”