Measurement of protozoa, using phosphatidyl choline, and of bacteria, using nucleic acids, in the duodenal digesta of sheep fed chaffed lucerne hay (Medicago sativaL.) diets

1984 ◽  
Vol 102 (1) ◽  
pp. 33-44 ◽  
Author(s):  
A. John ◽  
M. J. Ulyatt

SummaryThe use of phosphatidyl choline (PC) as a marker of protozoa in duodenal digesta was examined in sheep fed chaffed lucerne hay (Medicago sativaL.; 330–950 g organic matter/day) either once daily or hourly.PC was present in rumen protozoa (N:PC-P = 185±6·4) but was not detected in rumen bacteria. Dietary intake of PC was less than 5% of the daily passage of PC from the stomach (7·49 mg PC-P/day). A comparison of the SA of PC-P in protozoa and in duodenal digesta of sheep given a continuous intraruminal infusion of32P-orthophosphate showed that the proportion of dietary PC-P in duodenal digesta was negligible.The limitations and validity of PC as a marker of protozoa in duodenal digesta are discussed. The daily passage of protozoal N from the stomach (1·38 ± 0·125 g/day) estimated with PC was not affected by frequency of feeding but protozoal N yield (4·96 ± 0·509 g/kg organic matter apparently digested) declined with increasing feed intake.The SA of DNA-32P, RNA-32P and readily extractable phospholipid-32P (REPL-32P) in rumen protozoa, bacteria and duodenal digesta were similar, showing that the DNA, RNA and REPL-P in duodenal digesta were of microbial origin. A method is described for the estimation of bacterial REPL-P and bacterial N in duodenal digesta using DNA, RNA or DAPA as markers.The calculated total microbial REPL-P (bacterial plus protozoal) in digesta using DNA or RNA as markers was in close agreement with values obtained by direct measurement. It was estimated that protozoa contributed 22 and 14% of microbial REPL-P and microbial N, respectively. Bacterial REPL-P and bacterial N values estimated with DAPA as the marker were higher than values obtained with DNA or RNA. These results are discussed with regard to the use of these markers.

2012 ◽  
Vol 109 (10) ◽  
pp. 1765-1778 ◽  
Author(s):  
Abdelhafid Keli ◽  
Genaro Olmos ◽  
Antonio de Vega ◽  
José A. Guada

An experiment was carried out to examine the effect of increasing the proportion of Wimmera ryegrass hay in a lucerne hay-based diet on net transfer of nutrients to the intestine, and on the disappearance ofn-alkanes in the reticulo-rumen and the hindgut of sheep. Following a latin square design, four adult ewes were fed 1:0, 0·33:0·67, 0·67:0·33 and 0:1 proportions of legume and grass. Increasing the proportion of ryegrass in the diet linearly decreased the intake of DM (P= 0·017), organic matter (P= 0·021) and N (P= 0·001). However, neutral-detergent fibre intake was not affected (P= 0·148), nor was its digestibility coefficient (P>0·10). Diet had no effect on duodenal flows of nutrients (P>0·10), although the proportion of N intake (NI) recovered at the duodenum as non-NH3N (NAN) increased linearly withLolium rigidumin the diet (P= 0·002). Full recovery of NI as NAN was achieved at NH3concentrations in the rumen below 110 g/l. Microbial N contribution to NAN varied in a quadratic manner (P< 0·05) with the proportion of grass in the diet, although efficiency of microbial synthesis was not affected (P>0·10). Duodenal recovery of consumedn-alkanes was not affected by diet and was complete for those present in higher concentrations in the forages. Isolated rumen bacteria contained significant amounts ofn-alkanes, contributing to the duodenal flow of these hydrocarbons in variable proportions depending on the diet consumed.


1995 ◽  
Vol 74 (5) ◽  
pp. 617-634 ◽  
Author(s):  
Jan Dijkstra ◽  
Seerp Tamminga

A previously described mathematical model, that simulates the metabolic activities of rumen bacteria and protozoa, was used to examine the contribution of protozoa to neutral-detergent fibre (NDF) degradation in the rumen of cattle. Comparisons between predicted and experimentally observed NDF degradation showed general agreement. Further simulations were performed with diets containing variable proportions of concentrate (between 0 and 1 kg/kg diet DM) and at intake levels ranging between 5·3 and 21·0 kg DM/d. The simulated protozoal contribution to NDF degradation was 17–21% at the lowest intake level. Except for the all-concentrate diets, raising the feed intake level reduced this contribution to 5–3% at the highest intake level. The changes in contribution of protozoa to NDF degradation were related to variations in the fibrolytic bacteria: protozoa value and the NDF-degrading activities of protozoa predicted by the model. In simulations where dietary NDF levels were reduced and starch and sugar levels were increased independently, protozoal contribution to NDF degradation generally increased. These differences were reflected also in the generally increased protozoal contribution to NDF degradation predicted in response to a decreased roughage:concentrate value. The contribution of protozoa also generally declined in response to added N. These changes in predicted protozoal contribution to NDF degradation resulting from dietary variations provided possible explanations for the differences in rumen NDF degradation observed when animals are defaunated.


1984 ◽  
Vol 102 (1) ◽  
pp. 45-57 ◽  
Author(s):  
A. John

SummaryCell mass (dry matter per cell) and cell composition (concentrations of DNA, RNA, phospholipids, total N, a-dextran, diaminopimelic acid and 18 common amino acids) of rumen bacteria were measured at various times after feeding sheep chaffed lucerne hay (Medicago sativaL.) once daily. Cell composition was measured with sheep fed once hourly. Total DNA and RNA pool sizes in the rumen were also measured.While cell composition was not affected by level of feed intake (700 gv. 1050 g dry matter/day), total DNA, RNA and D.M. pool sizes in the rumen increased with increasing feed intake. With sheep on the once daily feeding regimen relative rumen pool sizes in rumen digesta at various times after feeding were: RNA, 4 > 14 > 0 h; DNA, 4 and 14 > 0 h; D.M. 4 > 14 > 0 h. With the hourly feeding regimen pool sizes were similar to the averaged daily values for sheep fed once daily.When sheep were fed once daily bacterial cell mass, DNA and phospholipid concentrations peaked at 12–14 h after feeding and subsequently decreased to the 0 h value. RNA concentration was maximal at about 4 h after feeding and declined to near the 0 h value at about 14 h. RNA concentrations in bacteria were highly correlated with gas production rates by whole rumen digesta. The ratio RNA:DNA was highest shortly after feeding, decreased to below the 0 h value at about 14 h and then increased to the 0 h value. The relative concentrations of a-dextran in bacteria were: 4 > 14 > 0 h. Cell composition witli sheep fed hourly tended to reflect the averaged daily values for sheep fed once daily.These results are discussed with regard to changes in estimated fermentation rate and pool size of bacteria in the rumen. It is suggested that changes in average composition (DNA, RNA, total N and RNA: DNA ratio) of mixed rumen bacteria reflect changes in the average growth rate of the population.


2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 172-172
Author(s):  
Ricardo M Garcia ◽  
Morgan T Thayer ◽  
Kayla M Mills ◽  
Jacob A Richert ◽  
Katharine G Sharp ◽  
...  

Abstract Lactating sows (N=140, York x Landrace) were used to evaluate the effects of a liquid prototype (LIQP) and dry (XPC®; Diamond V) Saccharomyces cerevisiae feed additives on sow and litter performance. Sows were fed a common gestation diet (0.55% SID-Lysine) until d112 of pregnancy and then allotted to lactation treatments: 1) Control diet (CON; 1.00% SID-Lysine), 2) CON +15 mL of LIQP from d112 to weaning (LIQ), 3) CON +0.20% of XPC from d112 to weaning (DRY), and 4) DRY +15 mL of LIQP from d112 to d7 post-farrowing (D+L). The LIQP was given once daily using an oral dose gun and XPC was included in the feed. Immunoglobulin concentrations were estimated on colostrum samples using Brix refractometer and piglet d 1 serum immunocrit ratio and plasma IgA and IgG. Daily sow water intake and daily feed intake (DFI) from d112 of gestation to d7 post-farrowing and weekly feed intake (ADFI) were recorded. There were no treatment effects on sow BW, backfat, or loin depth (P &gt;0.05) although sows from LIQ group had numerically smaller BW reductions compared to CON sows (4.9% vs 7.2%, P=0.19). LIQ sows had greater DFI and CON lower DFI during week 1 of lactation (P=0.04) as well as ADFI for weeks 2, 3, and overall lactation period (P&lt; 0.01) with DRY and D+L sows being intermediate. Water intake, immunoglobulins, and litter performance did not differ among treatments (P &gt;0.05) although pigs from LIQ sows, compared to CON, had numerically increased weaning (6.14 vs 5.82kg, P &gt;0.05) and litter weights (63.2 vs 60.1kg, P &gt;0.05). LIQ sows had 0.7 d reduced wean-to-estrus interval (P&lt; 0.001) and tended to have greater conception rates (P=0.07). In conclusion, LIQ supplementation of lactating sows improves feed intake, allowing sows to keep body reserves, and have better subsequent rebreeding performance.


1990 ◽  
Vol 41 (4) ◽  
pp. 791 ◽  
Author(s):  
FJ Hart ◽  
J Leibholz

Six Friesian steers (300 kg liveweight) were prepared with rumen and abomasal cannulae, and fed three artificially dried grasses at three levels of organic matter (OM) intake and at two stages of maturity. The grasses were paspalum (Paspalum dilatatum), oats (Avena sativa) and kikuyu (Pennisetum clandestinum). The apparent digestion of organic matter (OM) in the whole tract decreased with increasing maturity for all grasses. The proportion of OM digested in the rumen was greater for paspalum and kikuyu than oats, and increased with advancing maturity for paspalum and kikuyu. Microbial nitrogen flow from the rumen was 26 and 25 g/kg of OM apparently digested in the rumen for paspalum, 32 and 36 for oats and 25 and 14 for the early and late maturity kikuyu. The true degradation of grass protein in the rumen was between 0.70 and 0.80 for all three grasses, at all three feed intakes and for both stages of maturity of the grasses. Total rumen pool size was less for oats than paspalum or kikuyu. The retention time of particles and fluid in the rumen increased with decreasing feed intake for oats.


1972 ◽  
Vol 27 (1) ◽  
pp. 39-50 ◽  
Author(s):  
J. C. Macrae ◽  
M. J. Ulyatt ◽  
P. D. Pearce ◽  
Jane Hendtlass

1. In two experiments, sheep prepared with a rumen cannula and with re-entrant cannulas in the duodenum and ileum were continuously fed on diets of dried grass, dried grass plus formalin-treated casein, or dried grass plus untreated casein. Paper impregnated with chromic oxide was given once daily via the rumen fistula.2. In ten 24 h collections of digesta entering the duodenum and eleven 24 h collections of digesta reaching the ileum of sheep given dried grass, there were highly significant correlations between the 24 h flows of Cr marker and the corresponding flows of dry matter, organic matter, nitrogen, gross energy, hemicellulose and cellulose (P < 0.01) at both sites.3. Daily amounts of non-ammonia N and of individual amino acids entering and leaving the small intestine and of total N excreted in faeces and urine are given.4. Net retention of supplementary N was 36% when the supplement was administered as formalin-treated casein, but only 17% when it was administered as untreated casein.5. Formalin treatment of casein significantly increased the daily amounts of non-ammonia N entering the small intestine (P < 0.01) and the amounts of non-ammonia N apparently absorbed therein (P < 0.05).6. Apparent absorption of amino acids from the small intestine was significantly greater (P < 0.05) with treated casein than with untreated casein. There were relative increases in the small amounts of several free amino acids measured, including taurine, in the ileal digesta of sheep receiving the treated casein supplement.


2020 ◽  
Vol 12 (22) ◽  
pp. 9363
Author(s):  
Maristela C. Morais ◽  
Marcos Siqueira-Neto ◽  
Henrique P. Guerra ◽  
Lucas S. Satiro ◽  
Amin Soltangheisi ◽  
...  

Environmental benefits from bioenergy production derived from sugarcane crop residues (straw) can be lost by soil organic matter depletion resulting from excessive straw removal rates from fields. Soil organic carbon stock is the core for sustaining soil health, supporting nutrient cycling, and sequestering carbon dioxide. To find out that how much sugarcane straw can be removed from the field to produce bioenergy without changes in soil C concentrations, we investigated effects of straw removal rates (total, moderate, and no removal of sugarcane straw) on soil carbon and nitrogen fractions in an Oxisol and an Ultisol in southeastern Brazil for two years. Soil C and N fractions were affected by increased rates of straw removal at the second year. In the Oxisol, total straw removal decreased labile and microbial-C by ~30% and soil C stock by 20% compared to no straw removal. No removal decreased microbial-N and total N stock by ~15% and ~20%, respectively. In the Ultisol, no straw removal resulted in increases in C stock by >10% and labile and microbial-C by ~20% related to total straw removal. Total straw removal showed more microbial-N (~10%) and total-N stock (~25%) compared to no straw removal. The moderate straw removal intensity (i.e., 8 to 10 Mg ha−1 of straw) may control the straw-C release to soil by straw decomposition. This study suggests that excessive straw removal rates should be avoided, preventing SOM depletion and consequently, soil health degradation. Moderate straw removal seems to be a promising strategy, but long-term soil C monitoring is fundamental to design more sustainable straw management and bioenergy production systems.


2019 ◽  
Vol 16 (18) ◽  
pp. 3543-3564 ◽  
Author(s):  
Ines Bartl ◽  
Dana Hellemann ◽  
Christophe Rabouille ◽  
Kirstin Schulz ◽  
Petra Tallberg ◽  
...  

Abstract. Estuaries worldwide act as “filters” of land-derived nitrogen (N) loads, yet differences in coastal environmental settings can affect the N filter function. We investigated microbial N retention (nitrification, ammonium assimilation) and N removal (denitrification, anammox) processes in the aphotic benthic system (bottom boundary layer (BBL) and sediment) of two Baltic Sea estuaries differing in riverine N loads, trophic state, geomorphology, and sediment type. In the BBL, rates of nitrification (5–227 nmol N L−1 d−1) and ammonium assimilation (9–704 nmol N L−1 d−1) were not enhanced in the eutrophied Vistula Estuary compared to the oligotrophic Öre Estuary. No anammox was detected in the sediment of either estuary, while denitrification rates were twice as high in the eutrophied (352±123 µmol N m−2 d−1) as in the oligotrophic estuary. Particulate organic matter (POM) was mainly of phytoplankton origin in the benthic systems of both estuaries. It seemed to control heterotrophic denitrification and ammonium assimilation as well as autotrophic nitrification by functioning as a substrate source of N and organic carbon. Our data suggest that in stratified estuaries, POM is an essential link between riverine N loads and benthic N turnover and may furthermore function as a temporary N reservoir. During long particle residence times or alongshore transport pathways, increased time is available for the recycling of N until its eventual removal, allowing effective coastal filtering even at low process rates. Understanding the key controls and microbial N processes in the coastal N filter therefore requires to also consider the effects of geomorphological and hydrological features.


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