Direct estimation of the extent of contamination of food residues by microbial matter after incubation within synthetic fibre bags in the rumen

Mathers, John C.; Aitchison, E. M.

doi:10.1017/s0021859600034675

Cited by 66 publications

(43 citation statements)

References 6 publications

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“…As previously observed [9,16,34], the microbial contamination of FM was very low. This fact, together with the higher concentrations of amino acids in crude protein in FM than in SAB, showed that amino acid corrections from microbial contamination were practically null for this feed.…”

Section: Discussionsupporting

confidence: 82%

In situ rumen degradation of amino acids from different feeds corrected for microbial contamination

et al. 2001

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-Variations of the amino acid profile produced by rumen actions were established for fish meal (FM), corn grain (CG), corn gluten feed (GF), dehydrated beet pulp (DBP), and lucerne hay (LH), using the nylon bag technique. The effects of degradation of soluble or insoluble proteins were measured by rumen incubations at 0 h (washout value) and 16 h, respectively. Rumen incubations were performed on four cannulated wethers and the microbial contamination of incubated residues was corrected using a continuous 15 N-intraruminal infusion and solid associated bacteria isolates as the reference sample. The results showed that rumen degradation of both soluble and insoluble proteins produced changes in the amino acid profile, which were not uniform among feeds. Differences between feed and insoluble protein amino acid composition were limited for FM and DBP, important for GF and LH, and intermediate for CG. Differences between insoluble and undegraded protein amino acid composition were also limited for FM, GF, DBP, and LH and important in CG. The results showed that the amino acid profile in the undegraded protein and in the whole feed should be close for FM, DBP and LH. On the contrary, in CG, important variations are expected, since both solubility and degradability effects produced changes with the same tendency for most of the essential amino acids. In particular, our results showed a great decrease in the lysine content of the undegraded protein, which increases the lysine deficiency of this feed. This decrease of lysine was also evidenced in GF.rumen degradation / amino acid profile / microbial contamination / 15 N Résumé -Dégradation ruminale in situ des acides aminés de différents aliments, corrigée par la contamination microbienne. Les variations produites par les actions ruminales sur le profil des acides aminés de la farine de poisson (FP), du grain de maïs (GM), du gluten feed de maïs (GF), de la pulpe de betterave deshydratée (PBD) et du foin de luzerne (FL) ont été déterminées par la J. González et al. 254

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Section: Discussionsupporting

confidence: 82%

In situ rumen degradation of amino acids from different feeds corrected for microbial contamination

et al. 2001

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“…The bags were incubated in two incubation series, on different days, for periods of 2, 4, 8, 16 and 24 h. All the bags of each incubation series were placed simultaneously in the rumen just before animals were offered the first meal of the morning (9:00 h). The specifications of the bags and incubations are in agreement with those of the INRA (14,9 vs. 20,8 % ; P < 0,01), pendant que la fraction insoluble potentiellement dégradable a résultée similaire (79,0 vs. 79,2 %). Au contraire, le taux de dégradation a été supérieur pour les AAT (11,5 vs. 8,4 % .…”

Section: Methodssupporting

confidence: 72%

“…This technique is also the most currently used to study amino acid degradation. However, true degradation values are always biased by the microbial contamination of incubated feed residues [4,14].…”

Section: Introductionmentioning

confidence: 99%

Rumen effective degradability of amino acids from soybean meal corrected for microbial contamination

et al. 2000

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-Rumen degradation kinetics and effective degradability of individual amino acids, total analysed amino acids (TAA) and crude protein (CP) of soybean meal were measured on four rumencannulated wethers using the nylon bag technique. Microbial contamination of the incubated residues was corrected using a continuous 15 N intraruminal infusion and isolated solid associated bacteria as a reference sample. TAA showed a lower soluble fraction (14.9 vs. 20.8%; P < 0.01), a similar insoluble-degradable fraction (79.0 vs. 79.2%) and a higher degradation rate (11.5 vs. 8.4% . h -1 ; P < 0.05) than CP. As a consequence, effective degradability was similar for TAA and CP (74.7 vs. 75.7%). Degradability values of individual amino acids varied moderately (range: ±6% of TAA degradability). Valine, isoleucine, leucine, alanine, aspartic acid and tyrosine showed significantly lower degradability than TAA, while the opposite effect was observed for histidine, threonine and glutamic acid. Degradability of individual amino acids was related to their soluble fraction (r = 0.877; P < 0.001).amino acids degradability / soybean meal / microbial contamination Résumé -Dégradabilité ruminale, corrigée par la contamination microbienne, des acides aminés du tourteau de soja. Les cinétiques de dégradation ruminale et la dégradabilité théorique des acides aminés individuels, des acides aminés totaux analysés (AAT) et des matières azotées totales (MAT) du tourteau de soja ont été établies par la méthode des sachets de nylon sur quatre béliers fistulés dans le rumen. Les résultats ont été corrigés en fonction de la contamination microbienne des résidus, moyennant l'infusion en continu de 15 N dans le rumen et l'emploi comme référence d'un échantillon de bactéries adhérentes isolées du rumen. Les AAT ont été moins solubles que les MAT Reprod. Nutr. Dev. 40 (2000) 579-586 579

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“…A great source of error with this method is the microbial contamination of feed particles within the artificial fibre bags, which results in an underestimation of CP degradation (Mathers and Aitchison, 1981;Südekum, 2005). Only few studies for quantifying this microbial contamination have been carried out and most in situ estimates of ruminal CP degradation simply neglect this microbial contamination.…”

Section: Introductionmentioning

confidence: 99%

“…Mehrez and Ørskov (1977) used diaminopimelic acid (DAPA), Mathers and Aitchison (1981) 35 S, and Varvikko and Lindberg (1985) 15 N and DAPA as microbial markers.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of microbial contamination of protein during ruminal <i>in situ</i> incubation of feedstuffs

Krawielitzki¹,

Schmidt²,

Voigt³

et al. 2006

J. Anim. Feed Sci.

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The aim of this study was to determine the dynamics of bacterial contamination of feedstuffs during ruminal in situ incubation and to quantify the effects of bacterial contamination on the ruminal in situ degradation of crude protein (CP). Two different approaches using 15 N as a marker were followed, namely: 1. ] and t denotes the incubation time (h). The A max values of most cereals ranged from 32 to 38% of the residue N. For roughages and straw, A max reaches 45 to 100%. A max , but not C, is significantly positively influenced by the NDF content in feedstuffs (P=0.049). The CP content of feedstuffs negatively affects C (P=0.006). The proportion of bacterial CP of total CP within the in situ bag residues was used to correct the apparent CP degradation rate. This correction was numerically lowest for protein concentrates and grains (0 to 3%) and highest for roughages (up to 50%). In conclusion, correction of ruminal protein degradation for bacterial contamination is necessary, especially for roughages. For cereal grains and protein concentrates it seems to be irrelevant.

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Direct estimation of the extent of contamination of food residues by microbial matter after incubation within synthetic fibre bags in the rumen

Cited by 66 publications

References 6 publications

In situ rumen degradation of amino acids from different feeds corrected for microbial contamination

In situ rumen degradation of amino acids from different feeds corrected for microbial contamination

Rumen effective degradability of amino acids from soybean meal corrected for microbial contamination

Dynamics of microbial contamination of protein during ruminal <i>in situ</i> incubation of feedstuffs

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