Ruminal fermentation, microbial growth and amino acid flow in single-flow continuous culture fermenters fed a diet containing olive leaves

• Published in: Journal of animal physiology and animal nutrition 2010-04, Vol.94 (2), p.227-236
• Main Authors: Molina-Alcaide, E, Martín-García, A.I, Moumen, A, Carro, M.D
• Format: Article
• Language: English
• Subjects: Amino Acids - chemistry; amino acids flow; Animals; Bioreactors; Fermentation; Goats; Hordeum vulgare; Male; Nitrogen; Olea; Olea - chemistry; olive leaves; Plant Leaves - chemistry; Rumen - metabolism; Rumen - microbiology; rumen fermentation; ruminal fermentation; Sheep; single-flow continuous-culture fermenters
• ISSN: 0931-2439; 1439-0396
• DOI: 10.1111/j.1439-0396.2008.00905.x

Six single-flow continuous culture fermenters were used to determine fermentation profile, microbial growth and amino acid (AA) flow promoted by olive leaves supplemented with barley grains and faba beans (OLSUP), and alfalfa hay (AH). Two incubation runs were carried out with three fermenters inoculated with ruminal fluid from wethers and three from goats. The inoculum source did not affect (p = 0.059 to 0.980) any of the parameters. Daily volatile fatty acid (VFA) production and carbohydrate digestibility were greater (p = 0.009 and 0.024, respectively) for AH, therefore the pH values were lower (p = 0.015) than for OLSUP. Acetate was greater (p < 0.001) and isobutyrate, isovalerate and caproate lower (p < 0.001 to 0.006) for AH with greater acetate/propionate (p = 0.014) and 'VFA/digested carbohydrate' (p = 0.026) ratios. Daily microbial N flow and efficiency were greater (p = 0.016 and p = 0.041) for diet AH. Individual AA flows were greater (p < 0.001 to 0.016) for AH, but microbial essential AA proportion was greater for OLSUP (p = 0.015). The results indicate that OLSUP promoted lower bacterial growth and AA flow than AH, which could have been partially due to a limitation of N availability to ruminal microbes.