Intestinal Bacteria Communication: Can You Hear Me Now? – Dr. Noah Litherland, Vita Plus

Posted on February 23, 2017 in Starting Strong - Calf Care
By Dr. Noah Litherland, Vita Plus dairy youngstock technical specialist
Historically, we believed bacteria functioned as individual cells.  The discovery of intercellular communication among bacteria led to the realization that bacterial communities are capable of coordinated activity.  The “language” used for this intercellular communication is based on self-generated signal molecules called autoinducers.  When sufficient bacteria are present, autoinducer signals allow bacteria to sense a critical mass or quorum.  Communication allows bacterial populations to synchronize group behavior and coordinate multicellular functionality.

Quorum-sensing pathogens require a large enough population before they mount an attack.  Mounting an attack can include increasing in numbers, producing toxins that damage the host, and decreasing the number of normal protective microflora.

What does this mean for calves?  Since most pathogens only attack once they have reached a quorum, you can improve calf responsiveness by providing a nurturing environment for beneficial intestinal bacteria, minimizing exposure to pathogenic bacteria, and recognizing the first signs of sickness and providing supportive therapy (electrolytes and thermal care).  The following preventative steps will also help block quorum-sensing bacteria.

Increase host resistance
Maintain energy and protein balance to prevent a deficit in both nutrients.  This can be achieved by feeding nutritionally responsible amounts of milk or the correct milk replacer program for your calf’s environment.  Energy demand is dramatically increased when a calf is mounting an immune response.

Oxidative stress occurs when free radicals are produced by infection.  Free radicals can damage all components of cells, including DNA.  Important antioxidants include selenium and vitamin E.  Feeding selenium-amino acid complexes increases the bioavailability of selenium.

Timely and correct use of vaccinations also reduces the risk and severity of infection.

Competitive exclusion
The normal microflora inhabitants of the gastrointestinal (GI) tract serve a very important role in competing for nutrients and space with potential pathogens.  This competitive exclusion is the normal microflora’s way of saying “no vacancy” to pathogens.  The beneficial bacteria (bifidobacterium) prevent pathogens from forming communities and creating a quorum, decreasing the likelihood of them mounting an attack.

Bifidobacterium also have a symbiotic relationship with the host, promoting gut health.  For example, butyrate is an end-product of bacterial fermentation that stimulates blood flow and increases integrity of tight cell junctions.  Adjacent cells in the intestine are joined together by proteins that hold the cells together and serve as a barrier.  When this barrier breaks down, leaky gut occurs, increasing the risk for systemic infection.  Another example of symbiotic relationships in the GI tract is lactic acid-producing bacteria, which decrease the pH of intestinal contents and prevent pathogen growth.

Evaluate the consistency of calf manure.  Calf manure should be firm. If you observe loose manure from an otherwise healthy calf, it indicates the rate of passage is too fast and the nutrition program needs to be adjusted.  An excessively fast rate of passage will flush out bifidobacterium and open the door for pathogens.

Direct killing
Bacteria produce bacteriocins, which are toxins that inhibit the growth of similar or closely related bacterial strains.  These chemicals work like antibiotics to shift microbial community profiles.  Research into bacteriocins is ongoing, but they are thought to facilitate the introduction of beneficial bacteria or directly inhibit the invasion of pathogens.

Yeast cell wall contains sugar (manose) residues, which can aid in blocking Salmonella species and E. coli from attaching to the lining of the intestines so they cannot proliferate and produce toxins.

Both beneficial and detrimental bacteria communicate with each other through quorum sensing.  We can help our calves grow more efficiently and maintain their health by providing a nurturing environment for beneficial intestinal bacteria and minimizing exposure to pathogenic bacteria.

Category: Animal health
Starting Strong - Calf Care