Effect of concentrates in a hay diet on the contribution of anaerobic fungi, protozoa and bacteria to nitrogen in rumen and duodenal digesta in sheep

Faichney, GJ; Poncet, C.; Lassalas, Bernadette; Jouany, J.P.; Millet, Liliane; Doré, J.; Brownlee, A.

doi:10.1016/s0377-8401(96)01059-0

Cited by 46 publications

(37 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Some studies have reported similar ratios of RNA:N (McAllan, 1982) or purine:N (Czerkawski, 1976;Volden et al, 1999) in rumen bacteria and protozoa, while other studies have indicated lower ratios in protozoa (Ling and Buttery, 1978;Arambel et al, 1982;Firkins et al, 1987;Stokes et al, 1991;Kanjanapruthipong and Leng, 1998). Protozoa can contribute to proportionately between 0.10 and 0.40 of MP supply (Harrison et al, 1979;Steinhouretal., 1982;Puma et al, 1988Puma et al, , 1992Punia andLeibholz, 1994;Faichney et al, 1997), and therefore lower purine:N ratios identified in protozoa (Firkins et al, 1987; Kanjanapruthipong cited by Kanjanapruthipong and Leng, 1998), tentatively suggests that exclusive use of bacterial purine:N ratios would underestimate microbial N flow.…”

Section: Purine Content Of Rumen Microbesmentioning

confidence: 99%

Estimation of microbial protein supply in ruminant animals based on renal and mammary purine metabolite excretion. A review

Shingfield¹

2000

J. Anim. Feed Sci.

View full text Add to dashboard Cite

The potential of mammary and renal purine metabolite excretion as a technique for the assessment of microbial protein supply in ruminant animals is reviewed. Data reported in the literature tends to support the validity of the assumptions of the technique that purines entering the duodenum are essentially microbial in origin and that following metabolism, purine catabolites (collectively allantoin, hypoxanthine, uric acid and xanthine) are quantitatively recovered in urine. The most convincing experimental evidence suggests that secretion of purine metabolites in milk is of little value for the assessment of microbial protein supply due a mumal correlation with milk yield. In contrast, use of urinary purine metabolite excretion does appear to provide estimates of microbial protein supply that, are in general, consistent with values derived using standard in vivo procedures. However, the accuracy of this approach is largely dependent on obtaining representative samples of rumen microbes and the ability to account for variations in non-renal excretion and endogenous purine losses. In conclusion, urinary purine metabolite excretion appears to represent a valid noninvasive procedure to assess relative differences, rather than quantitative estimates of microbial protein supply in ruminant animals.

show abstract

Section: Purine Content Of Rumen Microbesmentioning

confidence: 99%

Estimation of microbial protein supply in ruminant animals based on renal and mammary purine metabolite excretion. A review

Shingfield¹

2000

J. Anim. Feed Sci.

View full text Add to dashboard Cite

show abstract

“…The application of molecular biology techniques to the study of microorganisms in complex environments like the rumen is an exciting new area of research with the main focus falling on the bacterial populations through the use of probes derived from the nucleotide sequences of prokaryotic 16s ribosomal (r) RNA genes (for a review, see Mackie, 1996). Quite recently, the development of oligonucleotide probes specific for nucleic acids from anaerobic fungi has provided the opportunity for a more precise determination of both the total fungal biomass and also the proportions of specific fungal subpopulations within the rumen (Faichney et al 1991;Don5 et al 1993;Brownlee et al 1996;Millet et al 1996;Faichney et al 1997). The oligonucleotide probes, which were based on the DNA sequence of the eukaryotic 18s rRNA gene (18s rDNA) or on the varying internal transcribed spacer regions between the different rRNA genes (Brownlee, 1994), have been.directed at hybridizing to either rRNA or rDNA.…”

Section: Fungal Biomass Measurementmentioning

confidence: 99%

The role of anaerobic gut fungi in ruminants

1998

View full text Add to dashboard Cite

Anaerobic chytridiomycete fungi are found in the gastrointestinal tracts of sheep, cattle and goats, as well as in many other domesticated ruminant and nonruminant herbivores and a wide variety of wild herbivorous mammals. They are principally found associated with the fibrous plant particles of digesta and as free swimming zoospores in the fluid phase. The presence of large fungal populations in animals consuming mature pasture or diets largely composed of hay or straw together with the production of highly active fibre degrading enzymes lead to' the belief that anaerobic fungi may have a significant role to play in the assimilation of fibrous feeds by ruminants. While many early studies focused on anaerobic fungi because of their unusual biology and metabolism, the large part of subsequent research has emphasized the biotechnological potential of their cellulases, xylanases and phenolic esterases. In recent years, the extent of the contribution of anaerobic fungi to the nutrition of ruminants has also been established through studies of fungal populations in the rumen and the dietary factors which influence them, as presented in this review. Further, we discuss the evidence supporting an important contribution of anaerobic fungal populations in the rumen to feed intake and digestion of poor quality feed by domesticated ruminants. In conclusion, the review explores some different methods for manipulating fungi in the rumen for increased feed intake and digestion.

show abstract

“…Previously, rRNA genes were used for quantification of protozoa biomass 34,35 , but rRNA levels may vary dramatically during various life stages although the protozoa population does not undergo any change. Thus rDNA has been proposed as a specific and precise marker that can be accurately quantified by quantitative real time PCR [17][18][19] .…”

Section: Discussionmentioning

confidence: 99%

Analysis of Community Structure and Species Richness of Protozoa-Enriched Rumen Metagenome from Indian Surti by Shotgun Sequencing

et al. 2016

View full text Add to dashboard Cite

The present study applies metagenomics to characterize the diversity and relative abundance of protozoa residing in the rumen of Indian Surti buffalo (Bubalus bubalis). To increase protozoa representation in the metagenome, protozoa enrichment was performed by density sedimentation and confirmed by quantitative real time PCR. The highly enriched metagenome sample was subjected to shotgun sequencing by Ion Torrent PGM which resulted in 10,303,375 reads totalling 1.6 gigabases. The taxonomic profile obtained by comparison with SILVA SSU database showed predominance of the class Litostomatea (99.78%) followed by Coccidia (0.10%) and Aconoidasida (0.06%). At the genus level Isotricha (48.06%) followed by Polyplastron (9.90%), Dasytricha (9.87%) and Eudiplodinium (7.47%) were predominant. The taxonomic assignment based on protein coding regions showed discrepancy with the SSU-based assignments, possibly due to the absence of most eukaryotic genomes in public databases. According to the SEED subsystems annotation database, genes for protein metabolism were the most abundant followed by genes for RNA metabolism, regulation and cell signalling. The present study offers a preliminary snapshot of diversity, functional potential and relative abundance of protozoa within the Indian Surti buffalo rumen and also expands our knowledge of these unicellular eukaryotes present in the rumen ecosystem.Keywords: Buffalo rumen, metagenome, protozoa enrichment, quantitative real time PCR, shotgun sequencing.RUMEN, one of the most diverse ecosystems in nature, harbours a complex consortium of interdependent anaerobic prokaryotes, protozoa, fungi, bacteriophages and methanogens. These act synergistically to convert lignocellulosic feeds into volatile fatty acids serving as an energy supplement for host ruminants 1 . Owing to the complexity of rumen ecosystem and the intricate interactions among various microbial groups within the rumen, it is difficult to decipher a precise role for each microorganism. Despite the fact that rumen microbiomes have been studied extensively, a majority of them have focussed on domain bacteria, because of their numerical abundance and metabolic diversity 2 , thus leaving rumen fungi, archaea, bacteriophages and protozoa underexplored.Rumen protozoa, besides contributing nutrients 3 to the host animal, help in digesting carbohydrate and protein containing feedstuff by secretion of various saccharolytic and proteolytic enzymes 4,5 in microbial protein turnover 6 , modulation of bacterial populations 7-9 and association with methanogens 8,10 . Numerous species of ciliates occupy the rumen, where they constitute about half of the total microbial biomass 11 . Although bacterial species play a vital role in digestion, protozoa are reported to digest 25-50% of the total fibre 12 . The polymorphic nature and complexity in cultivation of protozoa, has hampered the assessment of their taxonomy within the rumen ecosystem.Traditionally, microscopy has been the preferred method for identifying and enumerating protozoal ...

show abstract

Effect of concentrates in a hay diet on the contribution of anaerobic fungi, protozoa and bacteria to nitrogen in rumen and duodenal digesta in sheep

Cited by 46 publications

References 24 publications

Estimation of microbial protein supply in ruminant animals based on renal and mammary purine metabolite excretion. A review

Estimation of microbial protein supply in ruminant animals based on renal and mammary purine metabolite excretion. A review

The role of anaerobic gut fungi in ruminants

Analysis of Community Structure and Species Richness of Protozoa-Enriched Rumen Metagenome from Indian Surti by Shotgun Sequencing

Contact Info

Product

Resources

About