Piglets treated with the enzyme lysozyme grew just as fast as piglets treated with in-feed antibiotics, according to studies by the US Agricultural Research Service (ARS).
The studies compared the growth rates and weight gains of 1,200 piglets fed one of three feeding regimens: standard corn/soybean meal; standard corn/soybean meal with lysozyme; standard corn/soybean meal with antibiotics chlortetracycline and tiamulin hydrogen fumarate.
Piglets fed lysozyme- or antibiotic-treated feeds grew approximately 12% faster than untreated pigs, even when stocked in uncleaned pens that presented an indirect immune challenge. Necropsies revealed that both of the treated groups also had longer villi in the gastrointestinal tract, which absorb nutrients from feed.
These results, which were published in Journal of Animal Science, suggest that lysozyme may provide a natural alternative to antibiotics used to improve feed efficiency and growth in pigs, the article stated.
“Finding safe and effective alternatives to traditional antibiotics will give swine producers viable options in the event that removal of traditional antibiotics is needed,” said William Oliver, lead author and physiologist with the ARS US Meat Animal Research Center in Clay Center, Nebraska.
Lysozyme, discovered in 1921 by Alexander Fleming, occurs naturally in mucus, saliva, tears and other bodily fluids of humans and animals. Today the antimicrobial properties of egg-white lysozyme are used in wine- and cheese-making.