title: Effects of a specific blend of essential oils on apparent nutrient digestion, rumen fermentation and rumen microbial populations in sheep fed a 50:50 alfalfa hay:concentrate diet.
abstract: OBJECTIVE
  An experiment was conducted to investigate the effects of a specific mixture of essential oils (MEO), containing thyme, clove and cinnamon EO, on rumen microbial fermentation, nutrient apparent digestibility and blood metabolites in fistulated sheep.
  
  
  METHODS
  Six sheep fitted with ruminal fistulas were used in a repeated measurement design with two 24-d periods to investigate the effect of adding MEO at 0 (control), 0.8, and 1.6 mL/d on apparent nutrient digestibility, rumen fermentation characteristics, rumen microbial population and blood chemical metabolites. Animals were fed with a 50:50 alfalfa hay:concentrate diet.
  
  
  RESULTS
  Ruminal pH, total volatile fatty acids (VFA) concentration, molar proportion of individual VFA, acetate: propionate ratio and methane production were not affected with MEO. Relative to the control, Small peptides plus amino acid nitrogen and large peptides nitrogen concentration in rumen fluid were not affected with MEO supplementation; while, rumen fluid ammonia nitrogen concentration at 0 and 6 h after morning feeding in sheep fed with 1.6 mL/d of MEO was lower (p<0.05) compared to the control and 0.8 mL/d of MEO. At 0 h after morning feeding, ammonia nitrogen concentration was higher (p<0.05) in sheep fed 0.8 mL/d of MEO relative to 1.6 mL/d and control diet. Ruminal protozoa and hyper ammonia producing (HAP) bacteria counts were not affected by addition of MEO in the diet. Relative to the control, no changes were observed in the red and white blood cells, hemoglobin, hematocrit, glucose, beta-hydroxybutyric acid, cholesterol, total protein, albumin, blood urea nitrogen and aspartate aminotransferase and alanine aminotransferase concentration. Apparent total tract digestibility of dry matter, crude proten, organic matter, and neutral detergent fiber were not influenced by MEO supplementation.
  
  
  CONCLUSIONS
  The results of the present study suggested that supplementation of MEO may have limited effects on apparent nutrient digestibility, ruminal fermentation and protozoa and HAP bacteria count, blood cells and metabolites.
authors.affiliation: Department of Animal Science, Faculty of Agriculture, University of Kurdistan, Sanandaj, Kurdistan, P.O. Box: 416, Iran.
authors.forename: N
authors.initials: N
authors.lastname: Khateri
authors.affiliation: Department of Animal Science, Faculty of Agriculture, University of Kurdistan, Sanandaj, Kurdistan, P.O. Box: 416, Iran.
authors.forename: O
authors.initials: O
authors.lastname: Azizi
authors.affiliation: Department of Animal Science, Faculty of Agriculture, University of Kurdistan, Sanandaj, Kurdistan, P.O. Box: 416, Iran.
authors.forename: H
authors.initials: H
authors.lastname: Jahani-Azizabadi
keywords: Apparent Digestibility; Essential Oils; Hyper Ammonia Producing Bacteria; Rumen Fermentation; Sheep