Effect of dietary supplementation with recombinant human lysozyme on growth performance, antioxidative characteristics, and intestinal health in broiler chickens.

Lysozyme is often used as a feed additive to act as an antibacterial protein that boosts the immune system of livestock and poultry while protecting against pathogens. To investigate the effects of recombinant human lysozyme (rhLYZ) from Pichia pastoris and chlortetracycline on broiler chicken's production performance, antioxidant characteristics, and intestinal microbiota, a total of 200, 1-d-old male Arbor Acres broiler chickens (46.53 ±â€…0.42 g) were selected for a 42-d experiment. Dietary treatments included a basal diet of corn-soybean meal supplemented with either 0 mg/kg (CON), 50 mg/kg aureomycin (ANT), 20 mg/kg rhLYZ (LOW), 60 mg/kg rhLYZ (MEDIUM), or 180 mg/kg rhLYZ (HIGH). Compared with CON, MEDIUM diet increased (P < 0.05) average daily gain (67.40 g) of broilers from day 22 to 42. In the early (1.29) and overall phases (1.69), MEDIUM led to a reduction (P < 0.05) in the feed conversion ratio of broiler chickens. Furthermore, in comparison to the CON and ANT, MEDIUM exhibited reduced (P < 0.05) levels of INF-γ and tumor necrosis factor-α in the serum. In the cecum, the abundance of Monoglobus and Family_XIII_AD3011_group was lower (P < 0.05) in the MEDIUM treatment compared to CON. Overall, supplementation of 60 mg/kg of rhLYZ improved growth performance, nutrient utilization efficiency, and serum immune function, while also influencing the composition of intestinal microbiota. This suggests lysozyme's potential to replace antibiotic additives in feed.

The aim of this study was to explore the effects of recombinant human lysozyme (rhLYZ) produced from Pichia pastoris and chlortetracycline on broiler chicken performance, antioxidant properties, and gut microbiota. A 42-d experiment was conducted, involving 200 1-d-old male Arbor Acres broiler chickens. We provided different diets: a standard diet (CON), a diet with 50 mg/kg aureomycin (ANT), a diet with 20 mg/kg rhLYZ (LOW), a diet with 60 mg/kg rhLYZ (MEDIUM), or a diet with 180 mg/kg rhLYZ (HIGH). The results showed that, compared to the control group, the MEDIUM group significantly increased the average daily gain of broilers to 67.40 g from day 22 to 42. Additionally, the MEDIUM group exhibited a reduced feed conversion ratio during both the early and overall growth stages of the chickens. Furthermore, serum levels of INF-γ and tumor necrosis factor-α were lower in the MEDIUM group compared to both the CON and ANT groups. In the cecum, the abundance of Monoglobus and Family_XIII_AD3011_group was also lower in the MEDIUM treatment compared to the CON group. Overall, supplementation with 60 mg/kg of rhLYZ improved growth performance, nutrient utilization efficiency, and serum immune function in broiler chickens while also influencing the composition of their intestinal microbiota. This suggests the potential of lysozyme as a replacement for antibiotic additives in feed.