The Escherichia coli-expressed human lysozyme (EHL), a new source of lysozyme that is different from egg white lysozyme and the human lysozyme expressed in the milk of transgenic animals, has not been investigated extensively. We evaluated the effects of dietary supplementation of EHL on growth performance, nutrient digestibility, fecal microbiota, fecal score, and hematology indicators in weaning pigs. A total of 150 21-d-old weaning pigs [(Landrace × Yorkshire) × Duroc] were randomly allotted to 3 treatments according to the initial body weight (6.73 ± 0.01 kg) for a 35-d trial (phase 1, d 1–7; phase 2, d 8–21; phase 3, d 22–35). Each treatment had 10 replicate pens with 5 pigs (mixed sex) per pen. Dietary treatments consisted of a basal diet (CON), and a basal diet supplemented with 2.5 mg/kg antibiotic growth promoter complexes (AGP) or 1 g/kg EHL. Body weight on d 35 (P = 0.001), average daily gain during d 22–35 (P < 0.001) and 1–35 (P = 0.001), gain to feed ratio during d 22–35 (P < 0.001), growth rate during d 22–35 (P < 0.001) and 1–35 (P = 0.002), and apparent dry matter digestibility (P = 0.044) in feeding weaning pigs with AGP or EHL containing diet were higher, whereas fecal score during d 1–7 (P = 0.002) and fecal coliform bacteria counts (P = 0.022) were lower than those fed with the control diet. Moreover, weaning pigs fed the diet supplemented with EHL had a higher gain to feed ratio during d 1–35 (P = 0.030) than the CON group. Supplementing AGP to the diet of weaning pigs led to a decrease of fecal lactic acid bacteria counts (P < 0.001) compared with those fed with EHL containing diet or the control diet. However, hematology indicators did not differ among all dietary groups. Therefore, EHL has the potential to be used as an alternative to antibiotics due to the comparable effects with AGP on the growth performance, nutrient digestibility, hematology indicators, fecal score, and fecal coliform bacteria counts, however, unlike AGP, EHL did not inhibit fecal lactic acid bacteria counts.
Key Words: Escherichia coli-expressed human lysozyme, fecal microbiota, weaning pig.
Presented at the 9th Symposium on Gut Health in Production of Food Animals, St. Louis, USA, 2021. For information on the next edition, click here.