Probiotics Help Fish Grow up Faster and Healthier

A new study suggests the use of probiotics that are often referred to as friendly bacteria can increase the success of raising rare ornamental fish to adulthood.

The study conducted by scientists at the Institute of Marine and Environmental Technology showed how the use of probiotics, the live micro-organism that are similar to beneficial micro-organisms found in the human gut, is not only good for humans but also for fishes.

On feeding probiotics to the baby zebrafish, they noticed acceleration in their development and it also increased their chances of survival into adulthood.

Tiny zebrafish are often used in genetic research because scientists can easily track changes in their development and the fish grow quickly. Apart from this, they also share many of the same genes as humans and can be used for studying cellular and physiological processes and their impact on humans.

"This is really exciting," said Jacques Ravel, a leading genomic scientist studying the role of the human microbiome in health and disease at the University of Maryland School of Medicine Institute for Genome Sciences. "Knowing you can colonize the gut of a zebrafish with a probiotic strain and improve its development becomes an interesting model for us to study the beneficial effect of probiotics in children and adults."

In this experiment the researchers used a probiotic strain Lactobacisllus rhamnosus that is found in yogurt. When the fish consumed this, the probiotic, which entered through their gills, settled in their gastrointestinal tract preventing bad bacteria from taking over and promoting growth, including advancing the development of bone, vertebrae and gonads.

"If you have increased growth and survival from each batch of hundreds of thousands of eggs that is a huge benefit," said study co-author Dr. Allen Place of the Institute of Marine and Environmental Technology.

Probiotics helped the zebrafish get through the uncertainties when their gastrointestinal tract was maturing. Probiotics increased their survival rate from 70 percent to 90 percent.

"We did not anticipate the enhancement in maturation," said Place. "When you look at various molecular markers of stress, the overall stress in the fish that were treated with the probiotic were lower--which may be the reason for the development."

The study was published in the September issue of PLOS ONE.