Studies on the in situ nitrogen degradability corrected for bacterial contamination of concentrate feeds in steers.

Beckers, Yves; Thewis, André; Maudoux, B.; François, Ετιεννε

doi:10.2527/1995.731220x

Cited by 28 publications

(18 citation statements)

References 37 publications

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“…Given the high extent of microbial contamination of the bag residues, correction of apparent N disappearance for microbial N estimated by feed 15 N dilution resulted in higher values of N degradability. Differences between apparent and corrected values were larger with LC than with EC ryegrass, confirming previous observations indicating that microbial contamination of the bag residues is greater as the nitrogen content of the feed incubated is lower (Varvikko and Lindberg, 1985;Beckers et al, 1995;Dixon and Chanchai, 2000). In spite of the apparent important proportion of microbial 15 N in total 15 N determined in the bag residue, the quantity of feed 15 N incorporated into bacterial cells did not affect the assessment of the contamination values based on the forage 15 N dilution (Table 3).…”

Section: Extent Of Microbial Contamination and Effect On Protein Degrsupporting

confidence: 88%

“…Protein degradability may be underestimated because part of the considered undegraded nitrogen is of microbial origin. The extent of microbial contamination may be variable depending on a number of factors, such as incubation time, type of feedstuff incubated and marker used for the identification of microbial and feed nitrogen fractions (Varvikko and Lindberg, 1985;Beckers et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

“…15 N can be used as a suitable and reliable marker either to label feed protein (Varvikko and Lindberg, 1985;Wanderley et al, 1999) or, more frequently, amino acids synthesized de novo by ruminai microorganisms and incorporated into the microbial protein (Beckers et al, 1995;Dixon and Chanchai, 2000). The technique based on feed 15 N dilution following incubation in the rumen of labelled feed takes into account all the microorganisms attached to the feed particles remaining in the nylon bag, and may result in accurate and reliable estimations of microbial N in the incubation residues.…”

Section: Introductionmentioning

confidence: 99%

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Effect of feed 15N incorporation into solid-associated bacteria on the in situ nitrogen degradability of 15N labelled Italian ryegrass

Kamoun¹,

López

Beckers

et al. 2007

Animal Feed Science and Technology

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The objective of this study was to examine the effect of microbial contamination of the incubation residue on the in situ nitrogen degradability of Italian ryegrass. Microbial nitrogen in the bag residues was estimated by the feed 15 N dilution procedure, and the incorporation of feed 15 N into the adherent bacteria was assessed after isolating a bacterial pellet and determining its 15 N enrichment. Isotopically labelled Italian ryegrass (fertilized with 15 NH 4 15 NO 3 ) was harvested either in spring (early cut) or in summer (late cut). Forages were incubated in the rumen of two steers for 6, 24 and 48 h. The proportion of microbial N per unit of total N in the bag residue increased with incubation time, ranging from 184 to 853 mg microbial N/g total N at 6 and 48h, respectively.15 N enrichment in the bacterial pellet was highest after 6 h of incubation (3.6 mg 15 N/g N) and then declined steadily (0.8mg 15 N/gN in 48-h residues). Microbial 15 N represented up to 0.422 g/g total 15 N in the bag residue, but the incorporation of feed 15 N into bacterial N did not account for more than 57 mg/g 15 N incubated, this incorporation rate decreasing progressively with incubation time. Correction of apparent N disappearance for microbial N resulted in higher values of N degradability, especially for the late cut grass. A further correction considering the amount of microbial 15 N had little effect on the estimation of corrected N degradability values. Therefore, some of the feed 15 N is incorporated into bacterial N, but this fraction has a minor effect on the estimation of total microbial N in the bag residue by the feed 15 N dilution approach, and hence on the estimation of corrected degradability values. Abbreviations:ADF, acid detergent fibre; D c , N disappearance corrected for microbial contamination; D c* , N disappearance corrected for the microbial contamination and for the amount of 15 N of microbial origin; EC, early cut grass; LC, late cut grass; NDF, neutral detergent fibre; N i , nitrogen incubated in the bag; N r , nitrogen remaining in the bag residue after incubation; N m , microbial nitrogen in the bag; N SAB, nitrogen in solid-associated bacteria; SAB, solid-associated bacteria

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Section: Extent Of Microbial Contamination and Effect On Protein Degrsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of feed 15N incorporation into solid-associated bacteria on the in situ nitrogen degradability of 15N labelled Italian ryegrass

Kamoun¹,

López

Beckers

et al. 2007

Animal Feed Science and Technology

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“…Considering current mean diet contents of OM and total lipids of both bacteria types together with those of The equation derived from current and previous data of this team is also supported by that obtained (Figure 2) using mean diet values (n = 41) of 15 N enrichment in LAB and SAB obtained in cows (Martin et al 1994;Yang et al 2001;Ahvenjärvi et al 2002; Reynal et al 2005; Brito et al 2006, Ipharraguerre et al 2007), steers (Firkins et al 1987;Beckers et al 1995; Kamoun et al 2014), sheep (Chicunya and Miller 1999, Martín-Urúe et al 1998, Ramos et al 2009González et al 2012), and in vitro (Ranilla et al …”

Section: Resultssupporting

confidence: 65%

“…Considering current mean diet contents of OM and total lipids of both bacteria types together with those of and González et al (2012), performed with identical procedures, the close correlation coefficient recorded (0.741; n = 26; p < 0.001) show also the previously indicated relation. Merry and McAllan (1983) The equation derived from current and previous data of this team is also supported by that obtained (Figure 2) using mean diet values (n = 41) of 15 N enrichment in LAB and SAB obtained in cows (Martin et al 1994;Yang et al 2001;Ahvenjärvi et al 2002;Reynal et al 2005;Brito et al 2006, Ipharraguerre et al 2007), steers (Firkins et al 1987;Beckers et al 1995;Kamoun et al 2014), sheep (Chicunya and Miller 1999, Martín-Urúe et al 1998, Ramos et al 2009González et al 2012), and in vitro (Ranilla et al 2000;Carro and Miller 2002). The independent term of this equation was also not different from 0 (p = 0.162).…”

Section: Discussionsupporting

confidence: 53%

Potenciación de la respuesta productiva en rumiantes mediante el empleo de proteínas protegidas

Royón¹

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SUMMARY XIThe main objective of this thesis project was to increase the protein efficiency in ruminant diets by using protected protein (sunflower meal and spring pea), and improving the prediction of microbial protein supply.Commercial sunflower meal (SFM) and spring pea (SP) were treated with 4 N solutions (200 mL/kg) of malic acid (268.2 g/L) or orthophosphoric acid (130.6 g/L). Daily, two fractions of 12.5 kg of one of these meals were successively sprayed with the tested acid solution in a concrete mixer using a sprayer. Both fractions were then mixed and allowed to rest for 1 h at room temperature. The blend was then dried in a forced air oven at 120 ºC for 1 h. Then the oven was turned off and the treated material was left in the oven overnight. During the drying process, the material was stirred every 30 min during the first 2 h and then every 60 min for the subsequent 5 h. This process was repeated until the amounts of treated flour needed for the different trials performed.In the first experiment (chapter 3), ruminal and intestinal digestion trials were conducted to study the effects of the application of these acid solutions and heat to protect proteins of SFM and SP against ruminal degradation using three wethers fitted with rumen and duodenum cannulae. The ruminal digestion study was carried out in three experimental periods in which the wethers were successively fed three isoproteic diets including SFM and SP, untreated or treated with malic or orthophosphoric acids. The experimental periods of 21 days included successively: 10 days of diet adaptation, SFM and SP particle ruminal transit study (days 11-14) and ruminal nylon-bag incubations (days 15-21). The meals incubated in each experimental period were those corresponding to the associated diet. Rumen bacteria were labelled from days 11 to 21 by continuous intra-ruminal infusion of a 15 N source and the rumen was emptied at the end of in situ incubations in each period to isolate solid adherent bacteria and liquid associate bacteria. The intestinal digestion trial was conducted twenty days after the end of the ruminal studies to eliminate the 15 N enrichment in the digesta. The tested samples XII were composite samples obtained pooling the different ruminally undegraded residues to be representative of the chemical composition of the ruminally undegraded fraction (RU).Wethers were fed the untreated diet to determine the intestinal digestibility of untreated and treated meals using the mobile nylon bag technique. In addition, protein in untreated and treated meals and their 0 h, composite and intestinally undigested samples were extracted and subjected to electrophoresis to determine the digestion site of the different protein fractions.Estimates of the RU and its intestinal digestibility of dry matter, organic matter (only for RU), crude protein (CP) and starch (only in SP) were obtained considering ruminal microbial contamination and particle comminution and outflow rates. When corrected for the microbial contamination taking place in the rume...

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Ruminal use of undegraded‐feed soluble protein and accuracy of the estimations of the nutrient content in ruminal bacteria

et al. 2020

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BACKGROUND: The possible escape from the rumen of undegraded-feed soluble proteins (SP) was investigated using nitrogen-15 ( 15 N) infusions (25 mg) in three rumen and duodenum cannulated wethers. Animals were fed three isoproteic diets differing in SP content and including protein concentrates either untreated (control) or treated with solutions of either malic acid (MHT) or orthophosphoric acid (OHT) and heat. RESULTS: Compared with control, MHT and OHT diets reduced ruminal concentrations of ammonia-nitrogen (NH 3 -N) by 35.9% (P = 0.007), non-ammonia nitrogen (NAN) by 36.8% (P = 0.007), and SP-nitrogen (SP-N) by 45.2% (P = 0.072) over the post-feeding period. Both NAN and SP-N were lower (P ≤ 0.040) for OHT than for MHT diet. The 15 N enrichment of NAN and SP-N did not vary either among diets or with time, and both values were closely related (R 2 = 0.965; P < 0. 001). Estimations, either using solid-associated bacteria (SAB) or liquid-associated bacteria (LAB) as a reference, indicated that 0.983 and 0.894 of SP-N (values averaged across diets) was of microbial origin, respectively, which would indicate a practically negligible ruminal escape of feed SP-N. Values of 15 N-enrichment in SAB and LAB fitted well to previously published SAB-LAB relationships, indicating a 22% underevaluation of the N supply from SAB when only LAB is used as a reference.CONCLUSION: Both the negligible ruminal escape of feed SP and the underevaluation of the bacterial nutrient supply as a consequence of the use of LAB as the only bacterial reference should be considered to improve ruminant protein feeding systems. Industry Data were analysed using the PROC MIXED of SAS version 9.3. 24 Characteristics of MFRL (pH, N fractions, proportions of microbial origin and 15 N enrichments) were analysed as repeated measures. The statistical model included diet, sampling time and

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Studies on the in situ nitrogen degradability corrected for bacterial contamination of concentrate feeds in steers.

Cited by 28 publications

References 37 publications

Effect of feed 15N incorporation into solid-associated bacteria on the in situ nitrogen degradability of 15N labelled Italian ryegrass

Effect of feed 15N incorporation into solid-associated bacteria on the in situ nitrogen degradability of 15N labelled Italian ryegrass

Potenciación de la respuesta productiva en rumiantes mediante el empleo de proteínas protegidas

Ruminal use of undegraded‐feed soluble protein and accuracy of the estimations of the nutrient content in ruminal bacteria

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