Colostrum and milk provide a complete diet for the neonate. In ruminants, colostrum is also the sole source of initial acquired immunity for the offspring. Milk therefore plays an important role in mammalian host defense. In colostrum, the concentration of immunoglobulins is particularly high, with IgG being the major immunoglobulin class present in ruminant milk, in contrast to IgA being the major immunoglobulin present in human milk. Immunoglobulins are transported into mammary secretions via specialized receptors. In addition to immunoglobulins, both colostrum and milk contain viable cells, including neutrophils and macrophages, which secrete a range of immune-related components into milk. These include cytokines and antimicrobial proteins and peptides, such as lactoferrin, defensins, and cathelicidins. Mammary epithelial cells themselves also contribute to the host defense by secreting a range of innate immune effector molecules. A detailed understanding of these proteins and peptides offers great potential to add value to the dairy industry. This is demonstrated by the wide-ranging commercial applications of lactoferrin derived from bovine milk. Knowledge of the immune function of milk, in particular, how the gland responds to pathogens, can be used to boost the concentrations of immune factors in milk through farm management practices and vaccination protocols. The latter approach is currently being used to maximize yields of bovine milk-derived IgA directed at specific antigens for therapeutic and prophylactic use. Increasingly sophisticated proteomics technologies are being applied to identify and characterize the functions of the minor components of milk. An overview is presented of the immune factors in colostrum and milk as well as the results of research aimed at realizing this untapped value in milk.

The aim of the study was to compare the compositions of the fecal microbiotas of infants fed goat milk formula to those of infants fed cow milk formula or breast milk as the gold standard. Pyrosequencing of 16S rRNA gene sequences was used in the analysis of the microbiotas in stool samples collected from 90 Australian babies (30 in each group) at 2 months of age. Beta-diversity analysis of total microbiota sequences andLachnospiraceaesequences revealed that they were more similar in breast milk/goat milk comparisons than in breast milk/cow milk comparisons. TheLachnospiraceaewere mostly restricted to a single species (Ruminococcus gnavus) in breast milk-fed and goat milk-fed babies compared to a more diverse collection in cow milk-fed babies.Bifidobacteriaceaewere abundant in the microbiotas of infants in all three groups.Bifidobacterium longum,Bifidobacterium breve, andBifidobacterium bifidumwere the most commonly detected bifidobacterial species. A semiquantitative PCR method was devised to differentiate betweenB. longumsubsp.longumandB. longumsubsp.infantisand was used to test stool samples.B. longumsubsp.infantiswas seldom present in stools, even of breast milk-fed babies. The presence ofB. bifidumin the stools of breast milk-fed infants at abundances greater than 10% of the total microbiota was associated with the highest total abundances ofBifidobacteriaceae. WhenBifidobacteriaceaeabundance was low,Lachnospiraceaeabundances were greater. New information about the composition of the fecal microbiota when goat milk formula is used in infant nutrition was thus obtained.

The gastrointestinal microbiota plays an important role in maintaining host health by preventing the colonization of pathogens, fermenting dietary co

Inappropriate responses to normal intestinal bacteria may be involved in the development of Inflammatory Bowel Diseases (IBD, e.g. Crohn's Disease (CD), Ulcerative Colitis (UC)) and variations in the host genome may mediate this process. IL-10 gene-deficient (Il10-/-) mice develop CD-like colitis mainly in the colon, in part due to inappropriate responses to normal intestinal bacteria including Enterococcus strains, and have therefore been used as an animal model of CD. Comprehensive characterization of changes in cecum gene expression levels associated with inflammation in the Il10-/- mouse model has recently been reported. Our aim was to characterize changes in colonic gene expression levels in Il10-/- and C57BL/6J (C57; control) mice resulting from oral bacterial inoculation with 12 Enterococcus faecalis and faecium (EF) strains isolated from calves or poultry, complex intestinal flora (CIF) collected from healthy control mice, or a mixture of the two (EF·CIF). We investigated two hypotheses: (1) that oral inoculation of Il10-/- mice would result in greater and more consistent intestinal inflammation than that observed in Il10-/- mice not receiving this inoculation, and (2) that this inflammation would be associated with changes in colon gene expression levels similar to those previously observed in human studies, and these mice would therefore be an appropriate model for human CD.