Determination of mechanisms of action of active carbons as a feed additive

Abstract

Activated carbon's porous structure allows it to adsorb a substrates, products and catalysts from the environment thus modificated the biocatalysis processes in digestive tract. Active carbons are currently used to remove solvents from gas streams and for water purification; however, few studies have examined the mechanisms of action of active carbon during the biotransformation processes in the digestive tracks. The potential benefits of using activated carbon in feed are uncertain because both its chemical and physical properties can vary significantly depending on the type of carbonaceous feedstock. However, the use of active carbons as dietary supplements can also bring many benefits during biotransformation processes in the gastrointestinal tract. Active carbons can adsorb toxins from the gastrointestinal tract and reduce excessive intestinal gas accumulation. The study concerning the adsorption of bacteria and vitamins on the porous structure of various species of active carbons is an important factor to determine their mechanism of action in biocatalysis in digestive system. The use of properly modified activated carbons as feed additives may have a beneficial effect on the development and functioning of breeding animals in the future. The results of our research show that the active carbon obtained from beech (KB), which contained, on average, 14% oxygen content by weight adsorbed bacteria, such as E. coli and S. aureus, better than all the other active carbons tested. Moreover, the meso- and macropores of carbon seem to contribute little to bacterial adsorption by active carbons. The electron microscopy studies confirmed that the bacteria adhered mainly to the active carbon surface. Our results also indicate that the examined active carbons from beech (KB), coconut shells (TE50), and hard coal (RB2) do not adsorb (or adsorb with very limited efficiency) the vitamins that are routinely added to feed, such as A, B1, D, and K. Broilers fed with feed mixtures supplemented with activated carbon (KB) resulted in increases in the weight of the chickens (∼2%) after 14 days of application and 2% lower feed consumption (conversion) relative to a control sample. Our data indicate that modifying the surface area and elementary content of active carbon may affect its specificity and selectivity and its capacity to absorb particles used in veterinary, human pharmacy, and cosmetology.

Keywords: Active carbon; Adsorption; Bacteria; Biotransformation processes modification; Broilers; Catalyst sorption; Digestive track; Feed additives; Vitamins.