Consumption of Lysozyme-Rich Milk Can Alter Microbial Fecal Populations

Department of Animal Science, University of California, Davis, California, USA.
Applied and Environmental Microbiology (Impact Factor: 3.67). 06/2012; 78(17):6153-60. DOI: 10.1128/AEM.00956-12
Source: PubMed


Human milk contains antimicrobial factors such as lysozyme and lactoferrin that are thought to contribute to the development of an intestinal microbiota beneficial to host health. However, these factors are lacking in the milk of dairy animals. Here we report the establishment of an animal model to allow the dissection of the role of milk components in gut microbiota modulation and subsequent changes in overall and intestinal health. Using milk from transgenic goats expressing human lysozyme at 68%, the level found in human milk and young pigs as feeding subjects, the fecal microbiota was analyzed over time using 16S rRNA gene sequencing and the G2 Phylochip. The two methods yielded similar results, with the G2 Phylochip giving more comprehensive information by detecting more OTUs. Total community populations remained similar within the feeding groups, and community member diversity was changed significantly upon consumption of lysozyme milk. Levels of Firmicutes (Clostridia) declined whereas those of Bacteroidetes increased over time in response to the consumption of lysozyme-rich milk. The proportions of these major phyla were significantly different (P < 0.05) from the proportions seen with control-fed animals after 14 days of feeding. Within phyla, the abundance of bacteria associated with gut health (Bifidobacteriaceae and Lactobacillaceae) increased and the abundance of those associated with disease (Mycobacteriaceae, Streptococcaceae, Campylobacterales) decreased with consumption of lysozyme milk. This study demonstrated that a single component of the diet with bioactivity changed the gut microbiome composition. Additionally, this model enabled the direct examination of the impact of lysozyme on beneficial microbe enrichment versus detrimental microbe reduction in the gut microbiome community.

  • Source
    • "The hLZ transgenic goats were developed to provide a source of milk with the protective properties of human milk to benefit the health of consumers of the milk. It is thought that lysozyme in human milk plays a role in establishing a beneficial gut microbiota (Lonnerdal, 2003) and when hLZ milk was fed to a human-relevant animal model (the pig), the fecal microbiota population was distinct from animals fed WT milk demonstrating that hLZ milk can indeed modulate gut microbial populations in a fashion similar to human milk (Maga et al., 2012). In these trials, pasteurized milk from mid lactation was fed to the animals, thus eliminating any role live bacteria would have had, and as these results show, there was no significant difference in the relative abundance of bacteria present at mid lactation between hLZ and WT milk nor was there any difference in milk components (Table 1) pointing to the direct activity of lysozyme in the intestinal tract or an indirect effect via some yet unidentified secondary metabolites present in the milk. "
    [Show abstract] [Hide abstract]
    ABSTRACT: To protect infants from infection, human milk contains high levels of the enzyme lysozyme, unlike the milk of dairy animals. We have genetically engineered goats to express human lysozyme (hLZ milk) in their milk at 68% the amount found in human milk to help extend this protection. This study looked at the effect of hLZ on bacteria in raw milk over time. As the microbial diversity of goats' milk has yet to be investigated in depth using next-generation sequencing (NGS) technologies, we applied NGS and clone library sequencing (CLS) to determine the microbiota of raw goat milk (WT milk) and hLZ milk at early, mid and late lactation. Overall, in WT milk, the bacterial populations in milk at early and mid lactation were similar to each other with a shift occurring at late lactation. Both methods found Proteobacteria as the dominant bacteria at early and mid lactation, while Actinobacteria surged at late lactation. These changes were related to decreases in Pseudomonas and increases in Micrococcus. The bacterial populations in hLZ milk were similar to WT milk at early and mid lactation with the only significant differences occurring at late lactation with the elevation of Bacillaceae, Alicyclobacillaceae, Clostridiaceae and Halomonadaceae.
    Full-text · Article · Apr 2015 · Food Microbiology
  • Source
    • "In addition studies in vivo have shown that feeding human lysozyme-containing transgenic goats' milk at 270 mg/l positively impacts GI morphology, serum metabolites, lymphocyte populations, and increases antiinflammatory cytokine expression in a porcine model (Brundige et al. 2008, 2010; Cooper et al. 2011). Consumption of the 270 mg/l hLZ-milk also has the ability to modulate the gut microbiota of healthy pigs, significantly increasing levels of Bifidobacteriaceae and Lactobacillaceae (Maga et al. 2012) and lowering levels of Escherichia coli in studies both in vitro and in vivo (Maga et al. 2006b, c). Pharming Group BV, a Dutch-based biotechnology company, has used genetic engineering to produce a herd of transgenic cows that express approximately 1·5–2·0 g/l recombinant human lactoferrin (rhLF) in their milk, a concentration within the range normally secreted in human milk (van Berkel et al. 2002). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Lactoferrin and lysozyme are antimicrobial and immunomodulatory proteins produced in high quantities in human milk that aid in gastrointestinal (GI) health and have beneficial effects when supplemented separately and in conjunction in human and animal diets. Ruminants produce low levels of lactoferrin and lysozyme; however, there are genetically engineered cattle and goats that respectively secrete recombinant human lactoferrin (rhLF-milk), and human lysozyme (hLZ-milk) in their milk. Effects of consumption of rhLF-milk, hLZ-milk and a combination of rhLF-and hLZ-milk were tested on young pigs as an animal model for the GI tract of children. Compared with control milk-fed pigs, pigs fed a combination of rhLF and hLZ (rhLF+hLZ) milk had a significantly deeper intestinal crypts and a thinner lamina propria layer. Pigs fed hLZ-milk, rhLF-milk and rhLF+hLZ had significantly reduced mean corpuscular volume (MCV) and red blood cells (RBCs) were significantly increased in pigs fed hLZ-milk and rhLF-milk and tended to be increased in rhLF+hLZ-fed pigs, indicating more mature RBCs. These results support previous research demonstrating that pigs fed milk containing rhLF or hLZ had decreased intestinal inflammation, and suggest that in some parameters the combination of lactoferrin and lysozyme have additive effects, in contrast to the synergistic effects reported when utilising in-vitro models.
    Full-text · Article · Dec 2013 · Journal of Dairy Research
  • Source
    • "Livestock genetically engineered to produce milk containing human milk antimicrobial components have the potential to readily supply milk that can improve human health. Previous work using the pig a target animal model for human health has established that the hLZ transgene product functions as intended when consumed (Cooper et al. 2011, 2013; Maga et al. 2012). Here we report that the hLZ transgene product behaved similarly in a non-target organism as histological differences found in both pre-weaning and post-weaning kid goats raised on hLZ milk were similar to those found in the target organism (pigs) and thus indicate that the hLZ transgene product has stable and consistent effects. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Risk assessment in transgenic plants is intrinsically different than that for transgenic animals; however both require the verification of proper transgene function and in conjunction, an estimate of any unintended effects caused by expression of the transgene. This work was designed to gather data regarding methodologies to detect pleiotropic effects at the whole animal level using a line of transgenic goats that produce the antimicrobial protein human lysozyme (hLZ) in their milk with the goal of using the milk to treat childhood diarrhea. Metabolomics was used to determine the serum metabolite profile of both the host (lactating does) and non-target organism (kid goats raised on control or hLZ milk) prior to weaning (60 days), at weaning (90 days) and 1 month post-weaning (120 days). In addition, intestinal histology of the kid goats was also carried out. Histological analysis of intestinal segments of the pre-weaning group revealed significantly wider duodenal villi (p = 0.014) and significantly longer villi (p = 0.028) and deeper crypts (p = 0.030) in the ileum of kid goats consuming hLZ milk. Serum metabolomics was capable of detecting differences over time but revealed no significant differences in metabolites between control and hLZ fed kids after correction for false discovery rate. Serum metabolomics of control or hLZ lactating does showed only one significant difference in an unknown metabolite (q = 0.0422). The results as a whole indicate that consumption of hLZ milk results in positive or insignificant intestinal morphology and metabolic changes. This work contributes to the establishment of the safety and durability of the hLZ mammary-specific transgene.
    Full-text · Article · Nov 2013 · Transgenic Research
Show more