NOV 08, 2017 1:24 PM PST

Use of Probiotics in Aquaculture Reduces Antibiotic-Associated Mortality

WRITTEN BY: Sarah Hertrich

Over the last several decades the growth of the aquaculture industry has accelerated. Aquaculture can be defined as the farming of aquatic organisms by intervening in the rearing process which results in the enhancement of production. Aquaculture has helped to increase the production of food as well as increase the availability of aquaculture byproducts in the pharmaceutical industry.

Researchers from Brown University and the University of Rhode Island suggest a probiotic solution for deaths associated with prophylactic use of antibiotics in fisheries. Credit: Aquaculture Coalition

Outbreaks in aquaculture associated with viral, bacterial and fungal infections have resulted in devastating economic losses worldwide. Control of aquatic diseases has relied mainly on the use of chemical additives and antibiotics. Unfortunately, the increased use of antibiotics has had significant public health impacts by promoting the persistence of antibiotic-resistant bacteria in the environment.

A recent study published in mSystems, discusses the effects of antibiotic use on the aquaculture microbiome. Use of antibiotics in mammals, particularly humans and mice, has been found to disrupt the host microbiome by decreasing microbial diversity. Decreasing microbial diversity reduces the number of “good” bacteria in the microbiome which can help fight off the “bad” bacteria, also known as “colonization resistance”. Therefore; repeated antibiotic treatment can lead to recurrent drug-resistant infections.

Interestingly, previous studies have shown that transferring healthy microflora from the intestine of a healthy individual to the intestine of an unhealthy individual can help to restore the diversity of the host microbiome and prevent infection in the unhealthy individual. Until now, there has been very little research on colonization resistance in aquaculture. Scientists have hypothesized that the use of probiotics could help reduce the number of antibiotic-associated infections in aquaculture as well.

In this study, researchers determined the effects of antibiotics on the mortality of black mollie fish, which were selected due to their ability to live in a wide range of environmental conditions and ability to eat a variety of different diets. Fish were acclimated to sterilized seawater and placed into 4 treatment environments: (1) probiotics only; (2) no treatment (control), (3) antibiotics plus probiotics and (4) antibiotics only. Antibiotics were administered daily from days 1-13 and probiotics were administered daily from days 8-13. All 4 treatment groups were challenged on day 13 with a known aquaculture pathogen, Vibrio anguillarum, to determine the effects of the various treatments on mortality rates. After 48 days, microbial communities within each fish tank were collected and assessed using whole genome sequencing.

The authors of the study found that antibiotic treatment significantly increased black mollie mortality. They were also able to identify two specific probiotic bacterial species able to colonize black mollie and able to reverse the effects of the antibiotics. These two probiotic species, Phaeobacter inhibens S4Sm and Bacillus pumilus RI06-95Sm, were resistant to antibiotics and could help fight off the challenge bacteria through colonization resistance.

Authors of this study suggest that use of probiotics can help to restore aquaculture microbiome diversity, particularly following treatment with cycles of antibiotics. Use of probiotics may also help boost the number of “good” bacteria in the microbiome which can help fight off infection.

Sources: mSystems, ISRN Microbiology

About the Author
  • I am a postdoctoral researcher with interests in pre-harvest microbial food safety, nonthermal food processing technologies, zoonotic pathogens, and plant-microbe interactions. My current research projects involve the optimization of novel food processing technologies to reduce the number of foodborne pathogens on fresh produce. I am a food geek!
You May Also Like
DEC 04, 2019
Clinical & Molecular DX
DEC 04, 2019
Genetic platform takes the guesswork out of catching infections
A physician is faced with 3 patients: an elderly person with a chronic cough, a child being wheeled out of surgery and a young mother with a high fever. Ho...
DEC 05, 2019
Earth & The Environment
DEC 05, 2019
Scientists Get a Closer Look at "The Plastisphere"
Plastic litter is a global problem, and some of the tiniest culprits are not visible to the naked eye. These microplastics have infiltrated the world's...
DEC 09, 2019
Microbiology
DEC 09, 2019
A Single-Celled Organism That Seems to Make Choices
A protist has been captured on video 'changing its mind.'...
DEC 20, 2019
Neuroscience
DEC 20, 2019
Are Migraines Caused by Unhealthy Gut Bacteria?
Research is increasingly pointing towards the importance of the gut-brain axis in regulating our health. Not only has the health of our gut bacteria, or mi...
JAN 06, 2020
Microbiology
JAN 06, 2020
Microbes May Offset Some of the Negative Impacts of Ocean Microplastics
About 70 percent of the trash in the ocean is made of plastic. There is so much plastic in our oceans, it's thought to have entered our food chain....
JAN 27, 2020
Microbiology
JAN 27, 2020
Microbes in Household Dust May Be Spreading Antibiotic Resistance
Bacteria live in household dust, and sometimes a few of those microbes are pathogenic or carry genes that confer resistance to antibiotics....
Loading Comments...