Rumen protozoa are rich in polyunsaturated fatty acids due to the ingestion of chloroplasts

Sharon A. Huws, Eun J. Kim, Alison H. Kingston-Smith, Michael R. F. Lee, Stefan M. Muetzel, Alan R. Cookson, Charles J. Newbold, R. John Wallace, Nigel D. Scollan*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

29 Citations (Scopus)

Abstract

Within this study, we investigated whether the polyunsaturated fatty acids (PUFA)-rich nature of rumen protozoa is a consequence of ingestion of PUFA-rich chloroplasts. Four Hereford x Friesian steers were offered hay [low 18:3 (n-3) and low chlorophyll concentration] followed by freshly cut perennial ryegrass [high 18:3 (n-3) and high chlorophyll concentration] for 16 days. On the 14th and 16th days, rumen protozoa as well as attached and planktonic bacteria were fractionated 1 h before (-1 h), 2 and 6 h postfeeding, and their fatty acid concentrations determined. Protozoa fractionated from fresh grass-fed steers were richer (P <0.05) in PUFA, except conjugated linoleic acid, for all time points compared with those from hay-fed steers. Protozoal density was higher (P <0.05) for grass compared with hay. Entodinomorphid abundance was 3.4 times higher on fresh grass (P <0.01) compared with hay. Confocal microscopy and transmission electron microscopy confirmed that Epidinium spp. were commonly saturated with intracellular cytoplasmic chloroplasts. These data suggest that engulfment of chloroplasts is a major contributor to the high 18:3 (n-3) concentration of protozoa.

Original languageEnglish
Pages (from-to)461-471
Number of pages11
JournalFEMS Microbiology Ecology
Volume69
Issue number3
DOIs
Publication statusPublished - Sep 2009

Keywords

  • chloroplast
  • STEARIC-ACID
  • DUODENAL FLOW
  • LOLIUM-PERENNE
  • planktonic and attached bacteria
  • BACTERIAL FRACTIONS
  • QPCR
  • WATER-SOLUBLE CARBOHYDRATE
  • VACCENIC ACID
  • rumen protozoa
  • DGGE
  • CONJUGATED LINOLEIC-ACID
  • CHEMICAL-COMPOSITION
  • fatty acid
  • DAIRY-COWS
  • RUMINAL BACTERIA

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