Lysozyme is a natural antibiotic that could provide an alternative piglet treatment in diets to improve growth and feed efficiency, according to a report in today’s American Society of Animal Science “Taking Stock” e-newsletter written by Sandra Avant of USDA’s Agricultural Research Service.

ARS scientists at the U.S. Meat Animal Research Center (USMARC) in Clay Center, NE, found that piglets fed lysozyme performed as well as those given a traditional antibiotic. Lysozyme is an enzyme with antimicrobial properties, and is found in the tears, saliva and mucus of animals as well as humans.

In an initial study led by physiologist William Oliver in the USMARC Nutrition Research Unit, 10-day-old pigs were weaned and divided into three groups. Pigs were put on a milk replacer diet that included granulated lysozyme, neomycin and oxytetracycline, or no antibiotic or lysozyme treatment. The 48 animals were weighed after two weeks.

The growth rate was similar in pigs given lysozyme compared with those on regular antibiotics, and both lysozyme and antibiotics decreased pathogen shedding.

Oliver and microbiologist James Wells, in the USMARC Meat Safety and Quality Research Unit, also examined lysozyme’s effects on growth development and gastrointestinal health of 24-day-old pigs.

A total of 192 pigs—96 males and 96 females—were weaned and separated into groups. Animals were randomly assigned to one of three groups that were fed either a dry pellet diet containing lysozyme, carbadox plus copper sulfate or no treatment. After 28 days, analyses revealed that lysozyme was as effective as antibiotics in increasing growth performance, improving feed efficiency and enhancing gastrointestinal health.

ARS is the chief intramural scientific research agency of the U.S. Department of Agriculture (USDA). These findings, published in the Journal of Animal Science, support the USDA priority of promoting international food security.