Probiotics like those found in yogurt are not only good for people --
they are also good for fish. A new study by scientists at the Institute
of Marine and Environmental Technology found that feeding probiotics to
baby zebrafish accelerated their development and increased their chances
of survival into adulthood.
This research could help increase the success of raising rare
ornamental fish to adulthood. It also has implications for aquaculture,
since accelerating the development of fish larvae--the toughest time for
survival--could mean a more efficient and safe system for bringing fish
to the dinner table. Tiny zebrafish are often used in genetic
research because scientists can easily track changes in their
development and the fish grow quickly. They also share many of the same
genes as humans and can be used for studying cellular and physiological
processes and their impact on human disease. "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." He and his
colleagues are currently looking into the effect of Lactobacillus rhamnosus probiotics on the gut development of premature infants. In the zebrafish experiment, researchers added Lactobacillus rhamnosus,
a probiotic strain sometimes used in yogurt, to the zebrafish water.
The fish drank the probiotic through their gills, and it landed 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 touch-and-go time when their gastrointestinal
tract is maturing. They are still living off yolk with which they are
born, and it is during this weaning period when most mortality occurs.
Adding probiotics to the water increases the survival rate of zebra fish
larvae from 70% to 90%. "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."
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