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Lysozyme as an alternative to antibiotics improves growth performance and small intestinal morphology in nursery pigs

W. T. Oliver, J. E. Wells
Journal of animal science 2013 v.91 no.7 pp. 3129-3136
N-glycoside hydrolases, antibiotics, antimicrobial properties, barrows, blood plasma, carbadox, copper sulfate, electrical resistance, feed intake, feed supplements, feeds, gilts, growth performance, ileum, immunoglobulin A, jejunum, lysozyme, males, sows, swine feeding, urea nitrogen, villi
Lysozyme is a 1,4-?-N-acetylmuramidase that has antimicrobial properties. The objective of this experiment was to determine if lysozyme in nursery diets improved growth performance and gastrointestinal health of pigs weaned from the sow at 24 d of age. Two replicates of 96 pigs (192 total; 96 males, 96 females) were weaned from the sow at 24 d of age, blocked by BW and gender, and then assigned to 1 of 24 pens (4 pigs/pen). Each block was randomly assigned 1 of 3 dietary treatments for 28 d: control (two 14 d phases), control + antibiotics (carbadox/copper sulfate), or control + lysozyme (100 mg/kg diet). Pigs were weighed and bled on d 0, 14, and 28 of treatment. Blood was analyzed for plasma urea nitrogen (PUN) and IgA. At 28 d, pigs were killed and samples of jejunum and ileum were collected and fixed for intestinal morphology measurements. An additional jejunum sample was taken from the median BW 12 pigs per treatment to determine trans-epithelial electrical resistance (TER). Pigs consuming antibiotics or lysozyme grew at a faster rate than control pigs (0.433 ? 0.009 and 0.421 ? 0.008 vs. 0.398 ?0.008 kg/d, respectively; P < 0.03), which resulted in heavier ending BW (20.00 ? 0.31, 19.8 ? 0.29, and 18.83 ? 0.32 kg, respectively; P < 0.03). Feed intake was not different (P > 0.48), but Gain:Feed was improved in pigs consuming antibiotics or lysozyme (0.756 ? 0.014, 0.750 ? 0.021, and 0.695 ? 0.019 kg/kg; P < 0.05). Immunoglobulin A (P < 0.03) and PUN (P < 0.01) increased during the experiment, regardless of dietary treatment (P > 0.48). Dietary treatment did not affect TER (P > 0.37), but gilts had lower TER compared to barrows (P < 0.04). No differences in villi height or crypt depth were observed in the ileum (P > 0.53). However, jejunum villi height was increased and crypt depth was decreased in pigs consuming antibiotics or lysozyme (P < 0.001), resulting in an increased villi height:crypt depth of 72% (P < 0.001). Thus, we concluded that lysozyme is a suitable alternative to carbadox/copper sulfate diets fed to pigs weaned from the sow at 24 d of age.