Successive changes in the epimural bacterial community of young lambs as revealed by scanning electron microscopy

Abstract

Scanning electron microscopy was used to determine the time of initial colonization of the rumen epithelium of young lambs and successive changes with time in the morphological composition of the epimural community. Tissue samples were obtained from two groups of lambs at 1, 2, 4, 6, 8, and 10 weeks of age. Comparisons were made with the epimural communities observed at 12 well-distributed sites in the rumen of a mature wether. Epimural bacteria were already present on the epithelium at 1 week of age. The morphological composition of the epimural community changed with age, with the pattern of succession being similar in both groups of lambs. A total of 24 morphotypes were distinguished by scanning electron microscopy; 17 were rod shaped, 4 were cocci, 2 were spiral, and 1 was filamentous. These morphotypes were further subdivided into: (i) those persisting after their initial colonization in young lambs and present in the adult (7 morphotypes), (ii) those seen only in the adult (2 morphotypes), and (iii) those present only in young lambs (15 morphotypes). The seven morphotypes present in both the lamb and the adult could be considered indigenous members of the epimural community. Several morphotypes appeared restricted in their colonization to certain regions of the papillae, suggesting the presence of microhabitats within the epithelial habitat. Two rod-shaped bacteria were repeatedly seen specifically attached to one another, suggesting an interspecific association.

Manipulating rumen microbiome and fermentation through interventions during early life: a review

“…In addition to the colonization pattern of the different microbial groups in the rumen, special attention should be paid to the microbial community associated to the rumen wall. Stewart et al (1988) stated that the epimural bacterial community is established shortly after birth and soon reaches concentration equivalent to those in the adult while the diversity of this community seem to change with age ( Mueller et al, 1984a ; Rieu et al, 1990 ). Mueller et al (1984a) described 24 morphological types of bacteria associated to the rumen wall in 1- to 10-week old lambs by using scanning electron microscopy, although only seven types, found in both the lamb and the adult, could be considered indigenous members of the epimural community.…”

Isolation and identification of adherent epimural bacteria during succession in young lambs

“…Samples. Tissue samples were obtained from four sites in the rumens of two groups of six lambs each (groups 1 and 2) at 1, 2, 4, 6, 8, and 10 weeks of age as described previously (19). By using these sampling times, two samples were obtained during the preruminant stage, three during the transitional stage, and one during the ruminant stage; the stage of development was determined by measurements of relative wet tissue weights of stomach compartments.…”

“…Thus, in an effort to describe the succession pattern and identify the indigenous members of the epimural community of the sheep rumen, an initial scanning electron microscopy (SEM) examination of the epimural community in a mature wether was conducted, and a combination of SEM and bacterial isolation was used to study the successive changes which occur in the epimural bacterial community from its establishment until it reaches climax. The results of the SEM examination, which describe successive morphological changes in the epimural community with time, were reported separately (19). The results of the isolation study, which describe the successive changes in generic composition of the epimural community, are presented here.…”

Efecto de la alimentación en la fase de lactancia sobre la eficiencia de utilización del alimento en el período posdestete y su relación con la microbiota del tracto digestivo, el estatus oxidativo e inmunológico en el ganado ovino = Effects of early feed restriction during the post-weaning period on feed efficiency, gastrointestinal microbiota, anti-oxidant status and immunity parameters of lambs

“…Adherida al epitelio del tracto gastrointestinal se encuentra una compleja comunidad bacteriana, denominada microbiota epimural, que se establece en los corderos desde los primeros días de vida (Mueller et al, 1984). Las bacterias que colonizan las mucosas están en íntimo contacto con el hospedador e interaccionan con él, de modo que participan activamente en la respuesta del sistema inmunitario (Chowdhury et al, 2007).…”

“…Las bacterias colonizan el tracto gastrointestinal inmediatamente después del nacimiento , diferenciándose a nivel del rumen en tres subpoblaciones que incluyen la asociada al líquido ruminal, la del contenido sólido y la adherida al epitelio o epimural (Li et al, 2012). La comunidad bacteriana epimural del rumen de los corderos alcanza en poco tiempo concentraciones similares a las de los adultos, mientras que su diversidad experimenta cambios significativos durante las primeras semanas de vida (Mueller et al, 1984, Rieu et al, 1989. A la microbiota epimural del rumen se le atribuyen importantes funciones como la utilización del oxígeno (Cheng et al, 1979), la hidrólisis de la urea (Wallace et al, 1979) y el reciclaje de tejido epitelial (McCoard et al, 2017), pudiendo también estar involucrada en el metabolismo de aminoácidos ) y de los ácidos grasos volátiles (Chen et al, 2012).…”