Effects of Catecholamines on Gut Microflora and Potential for Beta- Adrenergic Agonists to Impact Ruminal Fermentation

Abstract

Catecholamines are produced by chromaffin cells of the adrenal medulla and adrenergic and dopaminergic neurons from tyrosine. Catecholamines regulate many vital physiological and metabolic responses because of the location of receptors. The impact of catecholamines is not limited to mammals; direct effects of natural catecholamines on bacteria have been researched extensively to understand the potential impact of these compounds on bacterial infections in humans. Catecholamines have increased the growth of bacteria, virulence-associated factors, and adhesins and increased biofilm formation. Beta-adrenergic agonists are similar in structure and pharmacological properties to natural catecholamines. Beta-adrenergic agonists enhance performance of finishing cattle during the final days prior to harvest. Responses to beta-adrenergic agonists include increased average daily gain, improved feed efficiency, and increased carcass lean. These responses have been observed as a direct effect to the animal; however, a review of the literature suggests that the response to beta-adrenergic agonists also could be mediated by a direct or indirect effect on ruminal microorganisms. Ractopamine hydrochloride increased fermentation in vitro, particularly with increased amounts of degradable intake protein. Inclusion of ractopamine hydrochloride in vivo decreased ruminal concentrations of ammonia and amino acid. The rumen is host to a large population of diverse microorganisms, and a direct impact of a synthetic catecholamine on the microbial population could potentially alter fermentation and the ruminant performance. Reviewing literature on catecholamines and their direct impact on microorganisms could lead to improved decisions regarding dietary supplementation of beta-adrenergic agonists, threreby increasing the growth performance response in ruminants.

Effect of Supplementation with Saccharomyces Boulardii on Academic Examination Performance and Related Stress in Healthy Medical Students: A Randomized, Double-Blind, Placebo-Controlled Trial

“…It is unlikely, however, that such catecholamines increase pulse rates as they are poorly orally absorbed [62]. On the other hand, catecholamines released in the gastrointestinal tract may stimulate the growth of other microorganisms contributing to microbiota alterations [63]. Fourthly, West and al.…”

Effects of feeding dry-rolled corn-based diets with and without wet distillers grains with solubles and zilpaterol hydrochloride on performance, carcass characteristics, and heat stress in finishing beef steers1

“…Another explanation for decreased DMI when feeding βAA could be the similarities they share with endogenous catecholamines such as norepinephrine and epinephrine. Catecholamines affect gut motility and secretory responses in mammals (Walker and Drouillard, 2012). When gut motility is altered, it affects ruminal retention time of feedstuffs and subsequently can alter ruminal digestibility.…”

“…When gut motility is altered, it affects ruminal retention time of feedstuffs and subsequently can alter ruminal digestibility. Intensity and frequency of ruminal contractions are decreased when βAA are fed (Walker and Drouillard, 2012). Ruminal contractions are the mechanism in which digesta is mixed within the rumen, which aids the microbial populations with digestion.…”

Symposium review: Microbial endocrinology—Why the integration of microbes, epithelial cells, and neurochemical signals in the digestive tract matters to ruminant health

“…Little is known concerning the neurohormonal innervation of the alimentary tract, although the ruminal epithelium does not possess the neurohormonal signaling circuitry that is present in the intestinal mucosa (Kitamura et al, 1987;Kitamura et al, 1993;Teixeira et al, 1998). There are, however, a few examples of research involving neuroendocrine-based applications such as the use of beta-adrenergic agonists to improve gain and efficiency in ruminants during the final days prior to harvest (Walker and Drouillard, 2012). As such, we do not know how microbial endocrinology concepts might apply to the ruminal microbial environment.…”