Differential expression of immune‐related genes in Pacific white shrimp, Litopenaeus vannamei, previously reared in biofloc and challenged with Vibrio harveyi

Abstract

This study aimed to evaluate possible modification of some immune‐related genes (hemocyanin, alpha2‐macroglobulin, prophenoloxidase and penaeidin3a) at the transcriptional level and signs of disease and mortality in Litopenaeus vannamei previously reared in biofloc and challenged with different Vibrio harveyi densities (103–108 CFU per ml). Gene expression was up‐ or downregulated based on bacterial density, indicating that defence mechanisms were activated to remove the pathogen. The genes analysed were not affected in the control group (without bacteria) or in the 103 CFU per ml group. The prophenoloxidase gene was expressed in the 104 CFU per ml group, whereas transcripts of the alpha2‐macroglobulin gene were detected in the 105 and 106 CFU per ml groups. However, the penaeidin3a and hemocyanin genes were upregulated in the 107 and 108 CFU per ml groups, in which signs of disease and mortality in shrimp were evident. These results suggest that the genes involved in the shrimp immune response fluctuate according to pathogen density, and when this density increases (e.g. 107 and 108 CFU per ml), the activated disease tolerance and defence mechanisms are inefficient. For this reason, disease and mortality were observed in the shrimp regardless of the previous condition of the biofloc.

Carbon sources improve water quality, microbial community, immune‐related and antioxidant genes expression and survival of challenged Litopenaeus vannamei Postlarvae in biofloc system

“…Our results indicate that the hemocyanin gene expression in the hepatopancreas significantly increased in the SCB treatment more than in the RS and RB treatments, and a significant difference was observed between 1.5 and 3 months. Similarly, Aguilera‐Rivera et al (2019) found that L. vannamei cultured in biofloc and infected with Vibrio harveyi exhibited an increase in the hemocyanin gene.…”

Impact of dietary administration of Arthrospira platensis free-lipid biomass on growth performance, body composition, redox status, immune responses, and some related genes of pacific whiteleg shrimp, Litopenaeus vannamei

“…The first strand cDNA was generated at 59°C for 50 min. Then, the designed primers designated in this experiment, including the Peroxiredoxin ( Prx ), Prophenoloxidase ( PPO1 ), p53-like protein isoform delta ( p53 ), and hemocyanin subunit L5 ( L5H ) genes, were presented in Table 2 and prepared for q-RT-PCR estimation, which was conveyed into a fluorometric iQ5 thermocycler (Bio‐Rad ® ) following the Aguilera‐Rivera et al [ 51 ] guidelines and applying the gene β ‐actin as the housekeeping gene [ 52 ].…”

“…At the end of the feeding trial, three equal pools of independent samples of each five L. vannamei shrimp (whole animals) were collected, washed twice with PBS (137 mM NaCl, 2.7 mM KCl, 8 mM Na 2 HPO 4 , 1.46 mM KH 2 PO 4 , and pH 7.4), and stored in RNA later 1 reagent (Sigma-Aldrich 1 ; 1w:5v) at-20˚C as ascribed by the procedure of Goncalves et al [50]. The total RNA extraction and quantitative real-time PCR followed the method of Aguilera-Rivera et al [51]. Briefly, the TRIzol reagents protocol (TRIzol © ; Life Technologies) was applied to extract the total amount of RNA then the obtained extraction was quantified at 260 and 280 nm using a NanoDrop spectrophotometer (Thermo Scientific).…”