Abstract
Hepcidin regulates iron homeostasis and host-defense mechanisms, while the hepcidin-like protein, Tilapia hepcidin (TH)2-3, functions as an antimicrobial peptide (AMP). Since AMP dietary supplements may be used as alternatives to antibiotics in livestock, we tested the effects of recombinant (r)TH2-3 as a dietary supplement in grouper aquaculture. rTH2-3 was produced by a Pichia pastoris expression system and exhibited thermostability and broad-spectrum antimicrobial activity. The feed conversion ratio and feed efficiency were determined in Epinephelus lanceolatus (grouper) fed with rTH2-3-supplemented diet for 28 days. In addition, grouper showed enhanced superoxide dismutase (SOD) activity after rTH2-3 feeding compared to regular-diet-fed fish. Gut microbiota analysis revealed that microbial diversity was enhanced by feeding grouper with 1% rTH2-3. After challenging grouper with Vibrio alginolyticus, differential regulation of immune-related genes in the liver and spleen was observed between the TH2-3 and regular-diet groups, including for genes associated with antimicrobial and pro-inflammatory functions, complement components, and major histocompatibility complex (Mhc). These findings suggest that overall immunity was improved. Thus, our results suggest long-term supplementation with rTH2-3 may be beneficial for aquacultured grouper. The beneficial effects of the supplement are likely based on changes in the commensal microbial community as well as immunomodulation.
Highlights
Antibiotic abuse may lead to multidrug-resistant bacteria and antimicrobial-resistant infections, making inappropriate use of antibiotics an important issue in industrial farming, such as aquaculture[1]
The results show that 1% methanol was sufficient to maximally induce recombinant TH2-3 (rTH2-3), as evidenced by a strong signal from the 6×His tag antibody (Fig. 1b, bottom)
For large-scale production of rTH2-3, an overnight culture of a small volume of yeast was moved to a fermenter for amplification (Fig. 2a)
Summary
Antibiotic abuse may lead to multidrug-resistant bacteria and antimicrobial-resistant infections, making inappropriate use of antibiotics an important issue in industrial farming, such as aquaculture[1]. Dietary supplementation with various AMPs has been reported to enhance host bacterial resistance, growth performance, and the gut microbe community. We have reported that a recombinant version of fish-derived Epinecidin-1 may be used as a feed additive to improve bacterial resistance and enhance immune-related gene expression[8,21,22]. Together, these studies show that AMP-based dietary supplementation can have beneficial effects in a wide variety of animals. We investigated the growth performance, bacterial gut microbiota, and immune-related gene profiles upon V. alginolyticus challenge
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
