Probiotics（益生菌） 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 Marine¹ and Environmental Technology found that feeding probiotics to baby zebrafish accelerated their development and increased their chances of survival into adulthood². This research could help increase the success of raising rare ornamental³（装饰的） fish to adulthood. It also has implications for aquaculture, since accelerating the development of fish larvae⁴--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 genetic⁵ research because scientists can easily track changes in their development and the fish grow quickly. They also share many of the same genes⁶ as humans and can be used for studying cellular⁷ and physiological⁸ 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 colonize⁹ the gut¹⁰ 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 premature¹¹ 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 tract¹², preventing bad bacteria from taking over and promoting growth, including advancing the development of bone, vertebrae（脊椎）, and gonads（生殖腺）.

 

"If you have increased growth and survival from each batch¹³ 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（胃肠道） is maturing. They are still living off yolk¹⁴ 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 molecular¹⁵ 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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