Development of rumen metabolism and ruminal epithelium in lambs.

The concentrations of volatile fatty acids and the development of rumen epithelium and microflora adhered to rumen wall in suckling lambs were observed. Total VFA concentration increased with age. The differences between the 1st (28.5 mmol.l-1) and 4th week of age (78.7 mmol.l-1) and between 6th (82.1 mmol.l-1 and 10th week of age (117.4 mmol.l-1) were significant (p < 0.01). The highest molar proportion of acetic acid (71.2 mol%) was observed in 1 week-old lambs and the highest molar proportion of propionic acid in 6 week-old lambs (20.8 mol%). Length and surface characteristics of papillae changed dramatically over the 10-week period. In samples from 1-week and 4-week-old lambs, the papilla surface was relatively smooth and epithelial cells were relatively thin and flat. In samples from 6-week and 10-week-old lambs the tissue topography was typically rough. In the 1-week-old lambs the cocci, single rods and short rods in pairs were present at very low population levels. At 4 weeks the epimural community became notably more complex and bacteria were present at a higher population level. The dominant morphotype at 6 weeks was a rod-shaped end-on attached bacterium. The epimural microflora became the most complex at 10 weeks.