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In tests to evaluate the effect of beneficial bacteria on the immune system, microbiologist Gloria Solano-Aguilar administers a probiotic treatment to a young pig. Click the image for more information about it.

Beneficial Bacteria Boost Intestinal Health

By Rosalie Marion Bliss
November 17, 2006

A probiotic supplement was found to stimulate the immune system and improve nutrient absorption in two separate animal studies recently conducted by Agricultural Research Service (ARS) scientists. Probiotics are living microorganisms that, when added to foods or dietary supplements in sufficient numbers, can benefit the consumer in one or more ways.

The studies were led by microbiologist Gloria Solano-Aguilar with the ARS Nutrient Requirements and Functions Laboratory, one of seven research units at the Beltsville (Md.) Human Nutrition Research Center. Solano-Aguilar received funding from Nestlé Nutrition of Glendale, Calif.

Healthy animals and humans benefit every day from trillions of natural intestinal bacteria. These friendly bacteria help keep "bad" bacteria from gaining a foothold that could lead to illness or disease. In the first study, the common probiotic strain Bb 12 was fed to three pregnant sows, while a placebo treatment was fed to three pregnant control sows. The scientists then fed the same Bb 12 treatment to half of each sow's litters, resulting in four experimental groups.

Solano-Aguilar studied gene expression patterns in tissue taken from each animal's lymph nodes, liver, spleen and intestine. She also studied the animals' intestinal contents. The team then compared the gene expression patterns in the pigs from all four groups. The probiotic was found to induce innate immune activity in the colon where the probiotic was in highest concentration.

In a separate study, half of a group of test pigs were treated with the Bb 12 probiotic before all of the test pigs were exposed to a worm infection. The researchers then compared the response to infection of the group of pigs that received the probiotic treatment with the response of those that did not receive the treatment. Preliminary results show better response to the infection—and improved nutrient absorption—in the group of pigs that were supplemented with the probiotic treatment prior to the infection.

Read more about the studies in the November/December 2006 issue of Agricultural Research magazine.

ARS is the U.S. Department of Agriculture's chief scientific research agency.