Particulate Markers Research Articles

COMPARATIVE DIGESTION AND DIGESTA KINETICS IN SHEEP AND CATTLE

Increasing the level of intake increased the rate of passage of fluid and particulate markers in cows and sheep. At high intake levels cows had lower digestion values and faster liquid turnover rates than sheep. Rumen liquid volume did not change with increasing intake in a high concentrate diet. Key words: Cattle, sheep, digestion, markers kinetics

EFFECTS OF APPLICATION PROCEDURE, pH AND MICROBIAL GROWTH ON RETENTION OF YTTERBIUM OR CERIUM BY BROME HAY

Factors affecting binding of Yb or Ce by forage particles were measured. Retention of markers was low regardless of application procedure (spray or soak). Live incubation media and acidic environment resulted in further marker displacement. The use of Yb or Ce as particulate markers may not be appropriate. Key words: Markers, cerium, ytterbium, rate of passage

A comparison of particulate markers for the estimation of digesta flow from the abomasum of sheep offered chopped oaten hay

Five sheep with simple cannulae in the rumen and abomasum were given a diet of chopped oaten hay at 95-98% of ad libitum intake from continuously moving belts. Flows of digesta from the abomasum were estimated by a double marker method by reference to 51Cr-EDTA as the fluid marker, and either 103Ru-P, lignin, or acid insoluble ash (AIA) as the particulate marker. Estimates were also made by reference to lignin as a single marker. Estimates of the weight of digesta leaving the abomasum daily were unaffected by the choice of particulate marker when used with 51Cr-EDTA, but were 25% lower when lignin was used alone. The estimated flows of dry matter and acid detergent fibre (ADF) were dependent upon the choice of markers. Compared with estimates of ADF flow given by 51Cr-EDTA and lignin, estimates given by AIA were lower (-24.6%) and those given by 103Ru-P were higher (+26.2%). Lignin alone gave estimates 1.6% higher. Observations on the distribution of 103Ru-P in digesta dry matter indicated a markedly higher concentration on fine than on large particles. It is concluded that lignin may be preferable to 103Ru-P as a particulate marker when certain coarsely chopped roughages are given to sheep, and when samples of digesta from the abomasum are obtained through a simple cannula.

Kinetics of [103Ru]phenanthroline and dysprosium particulate markers in the rumen of steers.

Two rumen cannulated steers consuming 5.5 kg air-dry lucerne (Medicago sativa) hay/d given at two-hourly intervals were used to study the kinetics in the rumen of the two particulate markers, 103Ru-labelled Tris-(1, 10-phenanthroline) ruthenium II chloride ([103Ru]P) and dysprosium (Dy). Provision of markers was achieved by allowing the steers to eat separated stems of the hay on to which had been sprayed solutions of the markers. The intake of large-particle (retained by a 3.2 mm mesh screen) dry matter (DM) in boluses and the rumen large-particle pool size measured by emptying the rumen were used to calculate the turnover rate-constant of this pool (1.02 and 1.19/d for steers A and B respectively). The decline with time of both [103Ru]P and Dy associated with large-particle DM in raft digesta was best described by two-compartmental kinetics. The first compartment apparently reflected a combination of the processes of mixing of labelled particles throughout the rumen contents, physical migration of marker from the labelled hay, and physical breakdown of large particles to small particles. The disappearance with time of [103Ru]P and Dy associated with small particles from the raft, ventral digesta and faeces from 3 to 8 d was well described by a single kinetic compartment with a rate constant similar to that of the second compartment of the large particles from the raft. [103Ru]P was rapidly distributed through both the raft and ventral digesta of the rumen. This observation, taken together with measurements of migration of [103Ru]P, suggested that on entering the rumen much of the [103Ru]P did not remain associated with the original feed material. The majority (63-64%) of Dy entered the raft digesta and mixed only slowly through the rumen contents. Some Dy (18-27%) apparently migrated rapidly from large particles and to small particles immediately after ingestion and there was also evidence for some slow migration from small to large particles. When used under the conditions described for this experiment neither [103Ru]P nor Dy was satisfactory as a marker to trace the passage through the rumen of a particular meal.

The passage of digesta markers through the gut of a folivorous marsupial, the koalaPhascolarctos cinereus

The passage of particulate and solute digesta through the alimentary tract of koalas fed the mature foliage ofEucalyptus punctata was investigated using radioisotopic markers. The solute marker was retained for longer than the particulate marker, the mean retention times of both markers (213 h and 99 h respectively) being longer than has been reported in most other mammals. Both the pattern of excretion in faeces of orally administered markers and data from a slaughter experiment indicated that the principal site of marker retention was the highly developed caecum/proximal colon which appeared to function as a single mixing compartment. An undettermined physiological mechanism caused solutes and fine particles of digesta to be selectively retained in the caecum/proximal colon. It is suggested that this caused the particulate marker to distribute in two pools situated in parallel producing a marker excretion curve different from any reported in other mammals. It is postulated that the rate of clearance of dietary fibre from the hindgut would be maximized by this mechanism and that this in turn would elevate the upper limit to intake of food, and hence digestible nutrient, by koalas. Such an adaptation would partially compensate for the physiological constraints on nutrient acquisition from fibrous diets imposed by small body size and thus may be important in enabling the koala to utilize a diet avoided by most other small herbivores.

Utilization of Bamboo by the Giant Panda

Two giant pandas were used to assess the utilization of bamboo as a feedstuff. Three 1-week-long digestion trials were conducted during which feed intake and fecal output were recorded. Passage of digesta was measured from both fluid and particulate markers administered at feeding. Results indicate that the giant panda, although highly specialized for the consumption of bamboo, is a very inefficient digester of bamboo. The pandas consumed up to 6% of body weight in dry matter per day, with bamboo dry matter digestibility averaging less than 20%. Apparent digestion coefficients for the structural carbohydrates of bamboo (27% for hemicellulose and 8% for cellulose) indicate that, unlike most herbivores, pandas do not rely heavily on the microbial degradation of plant material to fulfill their nutritional requirements. Additionally, the passage of digesta through the gastrointestinal tract of the panda was extremely rapid, with complete clearance of markers in less than 12 hours. The giant panda seems to have specialized to a feed source high in plant fiber without extensive modification of the digestive tract by selectivity in feeding, effective mastication, ingestion of large quantites, digestion of cellular contents rather than cell walls and rapid fecal excretion of the undigested residue.giant panda bamboo digestion gastrointestinal tract

Application of 14 MeV neutron activation analysis to the determination of Ce and Sm markers in biological materials

The rare-earth elements are very suitable multiple particulate markers for the investigation of matter flow in the gastro-intestinal tract of animals by means of the indicator activation method. A rapid determination of cerium and samarium in biological samples is possible with the aid of a 14 MeV neutron generator. The activity of139mCe has to be corrected for the interferences of28Al and143mSm. For the determination of samarium the radionuclides155Sm and153Sm are used. In order to increase the specific activity of these nuclides, which are produced mainly by means of nuclear reactions with thermal neutrons, the samples are irradiated inside a polyethylene moderator block. The deviation from the linearity of the calibration curve for samarium is discussed.

Sites of Organic Acid Production and Patterns of Digesta Movement in the Gastro-Intestinal Tract of the Raccoon

Twelve raccoons were used to assess the movement of fluid and particulate digesta through their gastrointestinal tract and to determine the diurnal variations in organic acid levels for the various segments of the tract. Fluid and particulate markers were administered at the time of meal feeding. Animals were killed at given intervals after the administration of markers. The gastrointestinal tract was removed and divided into seven segments for measurement of markers, pH, volatile fatty acids (VFA) and lactic acid content. The results indicate a rapid transit of the digesta through the entire gastrointestinal tract, with a mean retention time of less than 24 hours for all fluid and particulate markers. Particulate markers up to 2 cm in length were passed rapidly, with limited retention within the tract, much unlike animals with greater gut complexity. The apparent requirements for gut complexity and digesta retention presumably necessary for digestion by gut microflora were not evident in the raccoon. However, even in the absence of these characteristics, microbial fermentation of the ingesta occurred, as evidenced by the levels of organic acids produced. Colonic VFA concentrations achieved levels comparable to levels observed in the ruminants' foregut and the large intestine of the pony. Lactic acid was found throughout the entire gastrointestinal tract.

Extent of particulate marker (samarium, lanthanum and cerium) movement from one digesta particle to another.

SUMMARY An in vitro and in vivo experiment was performed to determine the extent of movement of samarium (Sm), cerium (Ce), and lanthanum (La) from the original feedstuff upon which they were adsorbed to other feed particles. The rare-earth elements were demonstrated to be tenaciously bound to the particulate phase, with essentially none of the element occuring in the liquid phase. When Sm, Ce and La were adsorbed onto grain, 92.6% of the elements remained with the grain after a 24 hr incubation period in vitro. When Sm, Ce and La were adsorbed onto hay, 99.2% of the elements remained associated with the hay after a 24 hr incubation period. Four rumen fistulated cows were fed Sin, Ce and La treated hay (1 g of element applied per .9 kg of hay) for 5 days. At the beginning of the sixth day, unmarked hay was fed and removed from the rumen every 6 hr for 24 hours. At 6, 12, 18 and 24 hr, 4.4, 5.8, 5.9 and 10.1% of the rare-earth elements on a ppm basis were detected on particulate fractions other than the one upon which they were originally placed. Possible reasons for the small amount of marker movement are discussed. Rare-earth elements can be used as multiple or simultaneous markers of ration ingredients as they pass

Effects of cold exposure on digestion, microbial synthesis and nitrogen transformations in sheep.

1. Six closely shorn sheep were given brome grass (Bromus inermis) pellets at the rate of 59 or 98 g dry matter (dm)/h and maintained at ambient temperatures of 2–5° and 22–25° for 35 d. Measurements of digestion, rate of passage of digesta, and nitrogen transformations were made during the last 13 d of temperature exposure.2. Cold exposure at the lower level of intake reduced the apparent digestibility of dm and organic matter (om) approximately 0.055 units. Apparent digestibility of dm and om was further decreased approximately 0.03 units with the higher level of food intake in the cold. Apparent N digestibility was significantly depressed from 0.62 to 0.59–0.60 for sheep exposed to cold at both levels of intake.3. Exposure of sheep to cold resulted in a decrease in the turnover time of the particulate marker, 103Ru, from 19 h to 10.12 h in the rumen, a decrease in rumen volume, and a significant increase in dm and om which escaped digestion in the stomach. Volatile fatty acid and methane production in the rumen were highly correlated with the amount of om digested in the stomach. Methane production in the rumen comprised 0.81 of total production in warm sheep, and 0.68–0.74 of total production in cold-exposed sheep.4. More om and non-ammonia-N were apparently digested in the intestines of sheep exposed to cold than in warm sheep at the same food intake, but the apparent digestibilities in the intestines of dm, om and non-ammonia-N leaving the abomasum did not change significantly between treatments. The retention time of 103Ru in the intestines was 17.18 h in sheep given 59 g dm food/h at both exposure temperatures, but was reduced to 12 h for cold-exposed sheep given 98 g dm/h. Methane production in the postruminal tract was increased at the higher food intake, but there was no difference between warm and cold-exposed sheep at the same food intake.5. The rate of irreversible loss of plasma urea and rumen ammonia was measured by infusion of [15N]urea and [15N]ammonium chloride. Exposure to cold reduced the irreversible loss of plasma urea from 0.85 to 0.75–0.77 g N/g N intake, and the irreversible loss of rumen ammonia from 0.66 to 0.57–0.61 g N/g N intake. The transfer of plasma urea-N to the rumen ammonia pool was significantly greater (9.5 g N/d) in the cold-exposed sheep than the value (7.3 g N/d) in warm sheep.6. The efficiency of microbial synthesis in the rumen was increased in cold-exposed sheep, and was related to the amount of N recycled through the rumen ammonia pool from intraruminal sources. The effect of dilution rate and fermentation patterns on efficiency of microbial synthesis is discussed.

The effect of diuretics on the faecal excretion of water and electrolytes in horses.

1. The effect on plasma, urinary and faecal electrolytes of frusemide and hydrochlorthiazide was measured in ponies, mean weight 180 kg. 2. The rapid loss in urine of large quantities of sodium had only a small effect on plasma sodium concentration. 3. Faecal sodium excretion was increased substantially after the administration of frusemide. 4. Frusemide increased faecal potassium during the 48 h following administration and faecal water in the 24/48 h period. It also produced a hypopotassaemia. 5. Hydrochlorthiazide increased faecal chloride during the 24 h after administration. 6. Frusemide increased the intestinal transit time of both liquid (polyethylene glycol) and particulate (Cr2O3) markers.

The effect of cold exposure of sheep on digestion, rumen turnover time and efficiency of microbial synthesis

1. Six closely shorn sheep were given brome grass (Bromus inermis) pellets at 1 h intervals and maintained at ambient temperatures of −1 to 1° and 18–21° for 28 d. Measurements of digestion were made during the last 10 d of temperature exposure.2. Cold exposure resulted in a reduction in apparent dry matter (DM) digestibility from 0·482 to 0·450, and of apparent digestibility of organic matter (OM) from 0·511 to 0·477. Neither apparent digestibility nor retention of nitrogen was affected.3. Apparent digestibility of OM in the rumen decreased from 0·300 to 0·242 with cold exposure, and was highly correlated with turnover time in the rumen of 108Ru, which was used as a particulate marker.4. The efficiency of microbial synthesis (g N incorporated into microbial cells/kg OM apparently digested) was correlated with the dilution rate of the solute marker (51Cr) and with the turnover time of the particulate marker (103Ru) in the rumen.5. Digestion in the intestine of DM and OM accounted for significantly more of apparent digestion in the whole gastrointestinal tract for sheep kept in the cold than for sheep kept in the warm. The apparent digestibilities of DM and OM entering the intestines were similar in sheep on both treatments, but significantly more non-ammonia-N was digested in the intestines of cold-exposed sheep.6. The influence of dilution rate of rumen fluid on the efficiency of synthesis of microbial cells in the rumen is discussed.

In vitro fusion of Acanthamoeba phagolysosomes. I. Demonstration and quantitation of vacuole fusion in Acanthamoeba homogenates.

Fusion of phagolysosomes (PLs) has been demonstrated to occur in vitro. Two separate cell homogenates of the ameba Acanthamoeba sp. (Neff) were prepared, each rich in PLs labeled with distinctive particulate markers. Portions of each were incubated together in vitro and fusion occurred as evidenced by the appearance of PLs containing both types of markers. Fusion was confirmed by electron microscopy, including serial sectioning. The membranes of fused vacuoles excluded the dye eosin Y. Surviving cells in the homogenates were not responsible for the observed fusion. Fusion was obtained using either synthetic markers (polystyrene and polyvinyltoluene latex) or biological markers (autoclaved yeast cells and glutaraldehyde-fixed goat red blood cells), or a combination of both. The specificity of PL fusion in vivo appeared to be maintained in vitro. As determined by light and electron microscopy, the fusion reaction was dependent on time and temperature, and on the initial presence of membrane around both marker particles. A minimum of 10% of the vacuoles fused by 10 min of incubation at 30 degrees C, and no rupture of the vacuoles was detected during this time. After 10 min of incubation, vacuole rupture began and fusion ceased. At a constant initial vacuole concentration, the extent of PL fusion in vitro was quantitatively reproducible. This appears to be a promising system for further investigation of membrane fusion in the lysosomal system.

Animal‐based methods of determining herbage intake and quality under grazing conditions

Abstract The better techniques used to quantify intake of pasture by ruminants require faeces excretion to be quantified. Chromium EDTA is a better marker for this purpose than is Cr2O3 as it can be analysed for more accurately and rapidly. In calculating faeces Excretion constantly infused Cr EDTAor ruthenium tris chloride, a particulate marker, requires less sampling of faeces for similar accuracy than when 12 hourly doses of Cr EDTA or Cr2O3 are administered per rumen. Under conditions where the mean retention time of a marker varies in the gut, faeces bags are the only way of accurately quantifying faeces excretion. After faeces excretion has been quantified, intake can be estimated by measuring digestibility of the ingested herbage in various ways. Suggestions are given when lignin and in vitro digestion are used for this purpose, which may increase the accuracy of intake measurements. The most accurate method of measuring digestibility at present involves using ruminants fitted with oesophageal fist...

Sites of Organic Acid Production and Pattern of Digesta Movement in the Gastrointestinal Tract of Geese

Sixteen geese were used to assess the movement of fluid and particulate digesta through their gastrointestinal tracts and to determine the diurnal variation in organic acid levels for the various segments of the tract. Fluid (polyethylene glycol and chronium-labeled ethylenediaminetetraacetic acid) and particulate markers (2 and 5 mm long) were administered with the meal. Animals were killed at given intervals after the administration of markers. The gastrointestinal tract was divided into nine segments for measurement of markers, pH, volatile fatty acids (VFA), and lactic acid contents. The data indicated a rapid evacuation of fluid marker from the foregut (crop, ventriculus, and proventriculus), while particulate markers were retained for extended periods of time. Retention of fluid marker was observed only within the cecum. Retrograde movement of particulate marker was demonstrated from the duodenum to ventriculus and proventriculus. Retrograde movement of fluid marker was observed from the cloaca to the colon, cecum, and distal third of the small intestine. However, particulate marker showed no retrograde movement in these segments of tract. Highest VFA levels were observed in the cecum. Retention of digesta and production of VFA within the colon were less than those noted for the dog, pig and pony. Lactic acid comprised less than 10% of the organic acids present in the gastrointestinal tract and were at their highest levels in the proximal and mid small intestine.

Sites of Organic Acid Production and Pattern of Digesta Movement in the Gastrointestinal Tract of Swine

Twelve swine were used to assess the movement of fluid and particulate digesta through their gastrointestinal tracts and to determine the diurnal variations in organic acid levels for various segments of the tract. Animals were fed twice daily at 12-hour intervals. Fluid (polyethylene glycol and chromium-labeled ethylenediamine-tetraacetic acid) and particulate markers (2 mm OD, and 2 mm and 1 and 2 cm long) were administration of markers. The gastrointestinal tract was divided into 12 segments for measurements of markers, pH, volatile fatty acids (VFA), and lactic acid (LA) contents. The data indicated a rapid evacuation of the fluid and the smaller particles from the stomach and their relatively rapid passage through the small intestine and cecum. There was, however, prolonged retention of both fluid and particulate markers first in the ascending and then in the descending colon. Larger particles (2 cm) were retained in the stomach throughout much of the 60-hour experimental period. LA levels were observed 8 hours postfeeding. The highest levels of VFA in gastric contents averaged 20 mmoles/liter. Gastrointestinal pH values showed significant changes with time postfeeding only within the stomach, where they did not reflect the changes in LA of VFA concentrations. VFA constituted 92% of the organic acids present in the large intestine. Their concentrations varied markedly with time (150-230 mmoles/liter), but the VFA at all times constituted the major anions in the large intestinal contents. The results demonstrated that digesta can be retained for prolonged periods of time in that swine stomach and colon. The high concentrations of organic acids also indicated that substantial degrees of microbial digestion of carbohydrates occurred at both sites.

Comparison of spot and continuous sampling for estimating duodenal digesta flow in sheep

Abstract The flow of duodenal digesta in sheep fed a diet of chopped dried grass was measured either by continuous 24-hour or spot sampling. Continuous samples were taken from sheep with re-entrant cannulae given chromic oxide paper (Cr2O3) as a flow-correction marker. Spot samples were taken from sheep with re-entrant or T-shaped (simple) cannulae given 103Ru-phenanthroline and 51Cr-EDTA as particulate and liquid phase markers respectively. No significant differences were obtained between the mean 24-hour flows of dry matter or liquid digesta measured by the two techniques, but spot sampling gave more variable results. Diurnal variations of duodenal digesta flow and marker concentrations in the continuously fed sheep showed that 103Ru-phenanthroline, 51Cr-EDTA, and PEG were more closely associated with their respective digesta phases than was Cr2O3.