Abstract
Supplementation of exogenous enzymes in chickens has been widely practiced, yet mechanisms responsible are not fully delineated. To investigate the effects of the dietary lysozyme on the growth performance and immunity of broiler chickens, a total of 120 one-day-old Ross 308 chicks were randomly allocated into four groups, each having three replicates (30 birds/group). The chicks were fed the starter (1–21 d) and grower (22–35 d) diets supplemented with 0 (control), 70 (LYZ70), 90 (LYZ90) and 120 (LYZ120) g of lysozyme 10%® per ton of basal diet for five weeks. The results revealed significant improvement in the growth performance and gut environment. There were significant decreases (P < 0.05 or 0.01) in the harmful fecal Coliform and Clostridia and an increase (P ˂ 0.05) in the beneficial Lactobacillus in the lysozyme-supplemented groups, especially in LYZ90. Moreover, the mRNA expressions of Cu, Zn-superoxide dismutase (SOD1), glutathione peroxidase (GSH-Px), interferon-gamma (IFN-γ), interleukin-10 (IL-10), and interleukin-18 (IL-18) were upregulated in response to lysozyme supplementation. In comparison to control, LYZ90 fed birds had a significant increase (P < 0.01) in the GSH-Px gene expression that enhances the antioxidant status of the gut. Expression of the biomarkers involved in the gut non-specific immunity indicated significant increases in the mRNA expression of INF-γ (P < 0.001), IL-10 (P < 0.001), and IL-18 (P < 0.05) in LYZ90 group. Also, serum globulin levels were significantly elevated (P ˂ 0.05) in lysozyme-supplemented groups. Histologically, the intestinal villi length and crypts depth were also enhanced (P ˂ 0.05) by dietary lysozyme supplementation. In conclusion, supplementation of broiler chickens with exogenous lysozyme, especially at 90 g of lysozyme per ton of basal diet dose rate, improved the growth performance, gut antioxidant status, and nonspecific immunity of broiler chickens.
Highlights
The intestinal microbiota has a great impact on host health, while its disturbances have been associated with various diseases [1]
Regarding the amount of lysozyme consumed by birds in lysozyme-supplemented groups, the individual bird consumed 0.557 mg of lysozyme per day in LYZ70, 0.711 mg in LYZ90, and 0.966 mg in LYZ120
Results of the IL-10 gene expression showed a significant increase in LYZ90 (P < 0.001) compared to control
Summary
The intestinal microbiota has a great impact on host health, while its disturbances have been associated with various diseases [1]. Gut microbial communities improve the animal health through the synthesis of vitamins, food digestion, and immunity. Antibiotics are the most potent factor leading to disturbances in the gut microbial community in human and animal [2]. Antibiotics have been used for many years in animal production. They can be used as growth promoters for broiler chickens because they control the growth of both the Gram-positive and Gram-negative bacteria in the gut [3]. The European Union has banned antibiotics’ supplementations in poultry flocks because of the potential human pathogens’ resistance toward certain antibiotics [4,5]. The poultry industry is increasingly in need of non-antibiotic alternatives to improve the gut health in commercial broiler chickens. Farmers have conveyed the use of alternative dietary supplements including probiotics, prebiotics, herbs, and exogenous enzymes instead of antibiotics [6,7,8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
