Benefits of Using Probiotics / Prebiotics in Cattle Feed

By: Heather Smith Thomas

p8Use of probiotics and prebiotics in animal feeds has been shown to benefit digestion,animal performance and the immune system. The microbe population of the rumen must be healthy and in appropriate numbers/balance for proper digestion of feed, and health of the animal. Probiotics are products that contain living microorganisms—bacteria and/or yeasts. Prebiotics are non-digestible sugars that play a beneficial role in aiding “good” microbes and protecting against the “bad” ones.    

Kyle Newman, PhD, microbiologist and lab director at Venture Laboratories in Kentucky says that at first glance it might seem counterproductive to use probiotics in the feedlot, thinking in terms of acidosis, because many probiotics are lactic acid bacteria. “But probiotics seem to prime the digestive system so there’s not much chance of problems with acidosis; the rumen can handle it better. In addition, the lactic acid produced by probiotic bacteria is normally in a form more utilizable by the host animal,” he says.

“When lactic acid is there, in a tolerable form, it can be gluconeogenic. Certain rumen bacteria can convert lactic acid into propionic acid, which can be used by the host animal for energy,” says Newman.

“The most widely studied use of probiotics is how these ‘good bacteria’ play musical chairs with bad bacteria and crowd them out so they cannot cause disease in the host. A lactobacillus product that Dr. Mindy Brashears developed at Texas Tech in her many feedlot studies reduces the numbers of E. coli O157:H7 in the gut. This E. coli is not a problem for cattle, but bad when it gets into human food,” he says. If there are more “good” bacteria and fewer “bad” bacteria, this reduces risk for meat contamination with pathogens like E. coli and Salmonella. 

Dr. Brashears, Director of the International Center for Food Industry Excellence, has done extensive research on ways to reduce harmful pathogens in pre or post-harvest animals. “The product we developed recently came to market, but the research work and development has been going on for at least 15 years,” says Brashears. 

“We isolated various strains of lactobacillus and evaluated commercially available probiotics. We tried to find the best lactic acid bacteria that would kill Salmonella and E. coli in the lab. Then we did tests to see if these bacteria would actually survive in the animal (resistance to digestive acids, bile, etc.) and how it behaved in rumen contents and fecal material. At the University of Nebraska we conducted pathogen-inoculated cattle studies,” she says.  

“In 2000, I transferred to Texas Tech and was able to do a large scale cattle study. There have been more than 25 studies on this product. We did some of the first studies, to show that it killed E. coli O157:H7 in the digestive tract and on the hide, in the research feedlot with 5 cattle per pen, and then in commercial feed yards with large pens of cattle,” says Brashears.

“We found 50 to 80% reduction of E. coli O157H7 on the hides, and in the fecal material. Actual reduction varies from study to study depending on the season, the prevalence of the pathogen, etc. but we always get a significant reduction,” she says.

“Not all probiotics reduce food-borne pathogens in the live animal. We evaluated several other strains that did not result in pathogen reductions. You can’t just take any probiotic and feed it and expect results,” she explains.

“This particular strain, called NP51, survives in the GI tract to do this job. The product should be fed daily,” says Brashears. In recent studies this product has also been proven to reduce Salmonella in the lymph nodes of cattle.

Newman explains that prebiotics may help feed the beneficial microbes that are already in the gut or may provide inert material that has some beneficial effect on the animal. “Sometimes we mix probiotics and prebiotics together. In other instances we may use the prebiotic by itself, but the good bacteria must already be there,” he says.

“The most prominent prebiotics on the market are the mannan oligosaccharides (MOS). They do many amazing things in the body, but they don’t feed the good guys. They have mannose sugar in a complex form that prevents bad bacteria from using it as an energy source, but many bad bacteria are attracted to mannose. The path­o­gens stick to it, like flies on fly-paper, and it takes them on through the tract–preventing them from colonizing the animal and causing disease,” says Newman.

Many different probiotics and prebiotics are available on the market. In the next issue of FEED-LOT, we will look at several studies on various products and how they have been found to benefit livestock in the feedyard.    

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