Weaning is a highly stressful event because mammals at this time experience significant alterations of intestinal morphology and physiological functions, and a shift in intestinal microbiome   because of changes in diet and social and environmental life conditions. For example, piglets suffer from significant intestinal microbiota disruption at weaning, including a decrease of Lactobacillus, and a loss of microbial diversity, whereas the increase of Clostridium spp., Prevotella spp. or facultative anaerobes such as Escherichia coli.
       Recently, a team of researchers from the Institute of Subtropical Agriculture, Chinese Academy of Sciences (ISA), Third Military Medical University，Yangzhou University，and University of Texas Health Science find that melatonin shows significant beneficial effects in weanling stress. Melatonin supplementation significantly improves the body weight gain and intestinal morphology for mice suffering from weanling stress.
       More importantly, melatonin supplementation reshapes the intestinal microbiota by increasing the relative abundance of Lactobacillus and intestinal metabolism. “That’s amazing because we can use melatonin to prevent or alleviate other intestinal disorders associating with the dysbiosis of intestinal microbiota, like diarrhea and inflammatory bowel diseases” said Wenkai Ren, a PhD student in ISA. Indeed, further experiment shows that melatonin significantly reduces (by about 60 %) the bacterial load of enterotoxigenic Escherichia coli (ETEC) in weanling mice.
       This research was supported by funding from National Key R&D Program (2016YFD0501201), Key Programs of frontier scientific research of the Chinese Academy of Sciences (QYZDY-SSW- SMC008), National Natural Science Foundation of China (31330075, 31372326, 31672433) and the Youth Innovation Promotion Association CAS.
       The result has been published in the Journal of Pineal Research with the title of “Melatonin alleviates weanling stress in mice: involvement of intestinal microbiota” The details could be found at https://www.ncbi.nlm.nih.gov/pubmed/28875556

Contact: Yin Yulong
        E-mail: yinyulong@isa.ac.cn
        Institute of Subtropical Agriculture, Chinese Academy of Sciences

       Figure 2. The composition of intestinal microbiota after melatonin supplementation in weanling mice.(Image by REN Wenkai)