Bacterial Colonization of the Equine Gut; Comparison of Mare and Foal Pairs by PCR-DGGE

Abstract

Horses, like all animals, are born without the symbiotic microbes that occupy the gastrointestinal tracts of mature animals. As grazing animals, horses rely on these microbes to fully utilize the grasses and other cellulosic feeds that they consume. Thus, colonization of the foal's gastrointestinal tract must occur between birth and weaning. The feces of nine mare and foal pairs were sampled from the day of parturition until 12 weeks of age, and the samples were analyzed by polymerase chain reaction amplification of the bacterial 16S rRNA gene and denaturing gradient gel electrophoresis (PCR-DGGE). The gels from feces of day (d) 0 foals had no or very few (x = 3, n = 6) bands, which indicates that species richness was low. The number of bands increased during the first 4 days of life, and by d 14 the foals and mares had similar numbers of bands (x = 28, n = 23). Some bands were present in young foals, but not in mares or in foals on d 42 or d 84, which indicated succession of bacterial species. When the PCR-DGGE profiles were compared with Dice's algorithm, all mare-foal pairwise similarities on d 14 and later were as great as the pairwise similarities between mares. These results are consistent with the idea that foals are born with a sterile gut, colonization proceeds rapidly, and a mature microbial community is present in the first few weeks of life.

Development of the faecal microbiota in foals

“…However, despite the clear importance of the intestinal microbiota, our understanding of the colonisation and development of this complex ecosystem is woefully inadequate; most investigations of the foal's intestinal microbiota have focused in the pathophysiology of foal heat diarrhoea and have typically involved bacterial culture [8][9][10], a method that provides only a very superficial assessment of the microbiota [11]. Culture-independent methods have been used to monitor temporal changes in bacterial profiles from foals [12,13], but while such methods are suitable for the detection of population membership changes, they lack taxonomic classification to determine what the changes are. Recently, next generation sequencing has been used to provide detailed characterisation of the equine faecal microbiota, but study of foals has been limited to investigation of changes in the intestinal microbiota of foals at 2 timepoints [14].…”

Identification of a Core Bacterial Community within the Large Intestine of the Horse

“…In horses it is apparent that the microbiome of the hind gut changes rapidly in early life from birth up until 56 days of age [9] and even in adult animals may not be stable. Indeed recent work using terminal restriction fragment length polymorphism demonstrated a statistically significant (P<0.001) bacterial community in the gut after a ten week period in six ponies fed a constant high fibre based diet [10].…”

Effect of Two Different Commercial DNA Extraction Kits on the Bacterial 16S Ribosomal RNA Gene Denaturing Gradient Gel Electrophoresis Profile of Arabian Gelding Feces

“…This was relatively 2) were more similar than between mares and some mare-foal pairs in a prior study [27]. In humans, it is believed that not only diet but also age and lifestyle influence gut microbial composition [40], which may be reflected in the large differences seen between fecal bacterial DGGE profiles of human individuals [40] as compared to the geldings in the present study.…”

“…Denaturing Gradient Gel Electrophoresis (DGGE) [3,[18][19][20] is a relatively low-cost PCR-based molecular fingerprinting technique for evaluating genetic diversity in a bacterial M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT 3 community and has been used to characterize bacterial community changes in the feces of dogs [21,22], mice [23], sheep [24], humans [25,26], and horses [8,20,27].…”