AUTHOR=Chang Yaqi , Mei Jia , Yang Ting , Zhang Zhenyu , Liu Guangmang , Zhao Hua , Chen Xiaoling , Tian Gang , Cai Jingyi , Wu Bing , Wu Fali , Jia Gang 

TITLE=Effect of Dietary Zinc Methionine Supplementation on Growth Performance, Immune Function and Intestinal Health of Cherry Valley Ducks Challenged With Avian Pathogenic Escherichia coli

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.849067

DOI=10.3389/fmicb.2022.849067

ISSN=1664-302X

ABSTRACT=<p>This study was carried out to evaluate the effects of supplemental zinc methionine (Zn–Met) on growth performance, immune function, and intestinal health of meat ducks challenged with avian pathogenic <italic>Escherichia coli</italic> (APEC). A total of 480 1-day-old Cherry Valley male ducks were randomly assigned to 8 treatments with 10 replicates, each replicate containing 10 ducks. A 4 × 2 factor design was used with four dietary zinc levels (0, 30, 60, 120 mg Zn/kg in the form Zn–Met was added to the corn–soybean basal diet) and challenged with or without APEC at 8-days-old ducks. The trial lasted for 14 days. The results showed that a dietary Zn–Met supplementation significantly increased body weight (BW) of 14 days and BW gain, and decreased mortality during 7–14-days-old ducks (<italic>p</italic> &lt; 0.05). Furthermore, dietary 30, 60, 120 mg/kg Zn–Met supplementation noticeably increased the thymus index at 2 days post-infection (2 DPI) and 8 DPI (<italic>p</italic> &lt; 0.05), and 120 mg/kg Zn–Met enhanced the serum IgA at 2 DPI and IgA, IgG, IgM, C3 at 8 DPI (<italic>p</italic> &lt; 0.05). In addition, dietary 120 mg/kg Zn–Met supplementation dramatically increased villus height and villus height/crypt depth (<italic>V</italic>/<italic>C</italic>) of jejunum at 2 DPI and 8 DPI (<italic>p</italic> &lt; 0.05). The <italic>TNF-</italic>α and <italic>IFN-</italic>γ mRNA expression were downregulated after supplemented with 120 mg/kg Zn–Met in jejunum at 8 DPI (<italic>p</italic> &lt; 0.05). Moreover, dietary 120 mg/kg Zn–Met supplementation stimulated <italic>ZO-3</italic>, <italic>OCLN</italic> mRNA expression at 2 DPI and <italic>ZO-2</italic> mRNA expression in jejunum at 8 DPI (<italic>p</italic> &lt; 0.05), and improved the MUC2 concentration in jejunum at 2 DPI and 8 DPI (<italic>p</italic> &lt; 0.05). At the same time, the cecal <italic>Bifidobacterium</italic> and <italic>Lactobacillus</italic> counts were increased (<italic>p</italic> &lt; 0.05), and <italic>Escherichia coli</italic> counts were decreased (<italic>p</italic> &lt; 0.05) after supplemented with Zn–Met. In conclusion, inclusion of 120 mg/kg Zn–Met minimizes the adverse effects of APEC challenge on meat ducks by improving growth performance and enhancing immune function and intestinal health.</p>