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PubMed2003

Detection of Escherichia coli O157:H7 in cattle feces using a polymerase chain reaction-based fluorogenic 5' nuclease (TaqMan) detection assay after secondary enrichment.

Currently, methods for recovering and identifying Escherichia coli O157:H7 from cattle feces are inconsistent and hindered by their inability to specifically and rapidly detect small numbers of organisms from this complex and highly variable matrix. A standard approach for isolating and characterizing E. coli O157:H7 from cattle feces was compared with a polymerase chain reaction (PCR)-based 5' nuclease assay specific for E. coli O157:H7 that included a secondary enrichment step. The PCR-based method proved a better indicator of the presence of the organism than the culture procedure. Retests indicated that the inclusion of a secondary enrichment step and the subsequent analysis by the 5' nuclease assay were reproducible and specific. Escherichia coli O157:H7 could be detected in fecal samples that were otherwise negative after a primary enrichment step, immunomagnetic separation, and plating onto sorbitol MacConkey agar plates containing cefixime and tellurite (CT-SMAC). In samples that were initially identified as culture positive but PCR negative, retesting of the culture isolates on CT-SMAC indicated that the sorbitol fermentation interpretations could frequently not be repeated in retests, whereas retesting using the 5' nuclease assay on the original samples demonstrated a high level of agreement with the initial PCR conclusions. These results indicate the necessity of confirmatory evaluation of isolates culturally recovered by standard cultural methods that involve the interpretation of CT-SMAC. The high level of disagreement between initial culture results and retests, and the high level of agreement between initial PCR results and retests, indicates the advantages of a gene-based detection system for identifying E. coli O157:H7 in cattle feces. Screening large numbers of fecal samples for E. coli O157:H7 would appear to be feasible by integrating the use of enrichment media in serial rounds of incubation with a PCR-based fluorogenic detection procedure in high throughput detection systems that had automated liquid-handling capabilities.

5'-Nucleotidase↗
PubMed2002

Extensive set of 16S rRNA-based probes for detection of bacteria in human feces.

For the detection of six groups of anaerobic bacteria in human feces, we designed seven new 16S rRNA-based oligonucleotide probes. This set of probes extends the current set of probes and gives more data on the composition of the human gut flora. Probes were designed for Phascolarctobacterium and relatives (Phasco741), Veillonella (Veil223), Eubacterium hallii and relatives (Ehal1469), Lachnospira and relatives (Lach571), and Eubacterium cylindroides and relatives (Ecyl387), and two probes were designed for Ruminococcus and relatives (Rbro730 and Rfla729). The hybridization conditions for the new probes were optimized for fluorescent in situ hybridization, and the probes were validated against a set of reference organisms. The probes were applied to fecal samples of 11 volunteers to enumerate their target bacterial groups. The Phasco741 and Veil223 probes both detected average numbers below 1% of the total number of bacteria as determined with the bacterial kingdom-specific Bact338 probe. The Ecyl387 probe detected about 1.4%, the Lach571 and Ehal1469 probes detected 3.8 and 3.6%, respectively, and a combination of the Rbro730 and Rfla729 probes detected 10.3%. A set of 15 probes consisting of probes previously described and those presented here were evaluated in hybridization with the fecal samples of the same volunteers. Together, the group-specific probes detected 90% of the total bacterial cells.

Bacteria↗
PubMed2006

Effect of ractopamine HCl supplementation on fecal shedding of Escherichia coli O157:H7 and Salmonella in feedlot cattle.

The effects of the beta-agonist ractopamine, recently approved for use in feedlot cattle to improve carcass quality and performance, on fecal shedding Escherichia coli O157:H7 and Salmonella in feedlot cattle was examined. In the first study, 20 feedlot steers and heifers were randomly assigned to receive ractopamine or no ractopamine (control) by way of oral bolus for 28 days. Fecal samples were collected daily, and shedding of E. coli O157:H7 determined. When examined during the entire 28-day experimental period, ractopamine decreased (P = 0.0006) the percentage of cattle shedding E. coli O157:H7 (58% vs. 42% for control and ractopamine treatments, respectively). A second study was conducted in a commercial feedlot facility in the southwestern United States. Eighteen pens of cross-bred beef heifers (approximately 100 head/pen and 9 pens/treatment) were randomly assigned to receive either 0 (control) or 200 mg ractopamine/head x d(-1). Fresh fecal samples (30/pen) were collected off the pen floor before ractopamine supplementation and again after approximately 28 days of ractopamine supplementation (within a few days of slaughter); the samples were cultured for E. coli O157:H7 and Salmonella. The percentage of animals shedding E. coli O157:H7 was decreased when data were pooled across replicates (P = 0.05) in ractopamine-treated cattle compared with controls. The percentage of animals shedding Salmonella tended to be higher (P = 0.08) with the ractopamine treatment when data were pooled across replicates. Although further research is required to confirm these results, the potential food safety implications of this research are intriguing.

Animals↗
PubMedDate not supplied

[Qualitative microscopic evaluation of fecal fats. Comparative study].

Microscopical examination of stool fat is an easy laboratory procedure a long ago used as screening for steatorrhea. Quantitative analysis of stool fat is accepted as the best method to diagnose fat malabsorption, but stool collection and the laboratory technique are more difficult and time-consuming. The main objective of this work was performed to compare the accuracy of microscopical qualitative examination in the same fecal sample collected in 500 patients, 299 adults and 201 children, for the three days quantitative method. The diagnosis of steatorrhea was confirmed by chemical determination in 237 adults (stool fat values greater than 5 g) and 131 children (stool fat values greater than 2 g). From these 62 patients adults and 70 children were admitted as controls. The study showed that microscopical qualitative fat evaluation is highly comparable with findings obtained by chemical dosage. However, it is important to consider the use of two microscopic examination for each fecal sample, that must be carefully homogenized.

Adult↗
PubMed2002

Clostridium perfringens toxin types from wild-caught Atlantic cod (Gadus morhua L.), determined by PCR and ELISA.

Ninety-five fecal samples from Atlantic cod (Gadus morhua L.), caught along the northern Norwegian coast, were examined bacteriologically for occurrence of C. perfringens. Isolates were examined by polymerase chain reaction (PCR) for genes encoding the four lethal toxins (alpha, beta, epsilon, and iota) for classification into toxin types and for genes encoding enterotoxin and the novel beta2 toxin for further subclassification. In addition, a commercial enzyme-linked immunosorbent assay (ELISA) kit for detection of C. perfringens alpha, beta, and epsilon toxin was used. Clostridium perfringens could be isolated in 37 fecal samples (38.9%) from cod. All isolates were C. perfringens toxin type A (alpha toxin positive) as determined by PCR and also ELISA. In addition, in isolates from two cod (2.1%) the gene encoding for beta2 toxin was found (A, beta2) by PCR. Genes encoding for beta, epsilon, and iota toxins and enterotoxin were not found. This is the first detection of C. perfringens alpha and beta2 toxin in cod and of beta2 toxin in fish in general. The origin of this bacterium in cod is discussed.

Animals↗
PubMed2002

Detection and identification of oxalate-degrading bacteria in human feces.

BACKGROUND: Oxalate is detoxified (catabolized) via the action of two enzymatic proteins, formyl coenzyme A transferase (encoded by the frc gene) and oxalyl coenzyme A decarboxylase (encoded by the oxc gene), contained in the cytosol of Oxalobacter formigenes that colonizes the human intestinal tract. It is speculated that oxalate-degrading bacteria decrease oxalate absorption from the intestines and their absence in the gastrointestinal tract correlates with the formation of calcium-oxalate urolithiasis. METHODS: Two methods of detection and identification of this bacterial strain were studied in human fecal samples collected from Japanese subjects. Genomic DNA was isolated from bacterial culture, and specific 16S rDNA was amplified by polymerase chain reaction (PCR) followed by sequencing. The oxc gene was amplified directly from human feces by PCR using the specific primers. RESULTS: Oxalate-degrading bacteria were identified by comparing the sequences of 16S rDNA. The oxc gene was directly detected from human feces by PCR. It was ascertained that a combined PCR detection method using both 16S rDNA and the oxc gene allows for identification of O. formigenes in human fecal samples. CONCLUSION: This detection and identification method of oxalate-degrading bacteria using 16S rDNA and oxc gene should be applied in examination of clinical samples.

DNA, Bacterial↗
PubMed1989

Detection and preliminary studies of small double capsid virus.

This article reports the detection of small double capsid virus and results of preliminary studies on its morphology, serology and relationship to gastroenteritis. A kind of small virus particles with morphological characteristics was found in fecal samples of 3 of 23 infants with autumn gastroenteritis. The average diameter of this virus particles is 34.1 +/- 1.1 nm, possessing core, double capsids and spoke-like capsomers. It can be differentiated from other viruses in morphology. Correlated antigenicity exists among 3 strains of the virus but not among other studied viruses and this virus. The titer of the antibody to small double capsid virus in convalescent phase-sera of 2 patients was more than 4-fold as high as that in control sera. This virus was absent in fecal samples of recovered patients as well as in those of normal infants. These show that small "double layer like" capsid virus might be one of the etiological agents of acute gastroenteritis.

Antibodies, Viral↗
PubMed2001

Shiga toxin-producing Escherichia coli in beef heifers grazing an irrigated pasture.

Shiga toxin-producing Escherichia coli (STEC) produce toxins that have been associated with several human illnesses. E. coli O157:H7 is the most well-studied STEC and was first associated with consumption of improperly cooked ground beef in 1982. E. coli O157:H7 is not the only foodborne STEC because other STEC serotypes are also associated with human illnesses. The objective of this study was to assess prevalence of STEC in 23 yearling beef (Angus) heifers grazing an irrigated grass pasture in spring (April), summer (July), fall (October), and winter (December) of 1999. A total of 86 fecal samples were rectally collected and were subjected to microbiological testing for the presence of STEC. Nine E. coli isolates from five heifers (one in spring and fall and three in winter) were toxic to Vero cells. Of these isolates, four were E. coli O157:H7, two belonged to the serogroup O6, one O39:NM, one O113:H-, and the final isolate was untypable. The STEC prevalence rate in our herd ranged from 4% (spring) to 15% (winter). Based on detecting both O157:H7 and non-O157:H7 STEC in our heifers, it is clear that screening fecal samples should not be limited to E. coli O157:H7. Identification of STEC-positive cattle prior to slaughter should help in reducing the risk of beef contamination with such foodborne pathogens if pre- and/or postharvest control measures are applied to such animals.

Animals↗
PubMedDate not supplied

Speciation of mercury excreted in feces from individuals with amalgam fillings.

Investigators established methods for the analysis of total mercury (Hg-total), oxidized mercury and mercury bound to sulfhydryl groups (Hg-S), mercury vapor (Hg0), and mercury from amalgam particles (APs) in fecal samples. Two individuals consumed mercury as a mercury-cysteine complex mercury vapor, and mercury from amalgam particles, and the cumulative excretion of mercury in feces was followed. Investigators found that 80% of the mercury from amalgam particles and mercury bound to sulfhydryl groups was excreted, but only 40% of the mercury vapor was excreted. Speciation of mercury excreted in feces from 6 individuals with a moderate loading of amalgam fillings showed that most of the mercury originating from the fillings consisted of oxidized mercury, which was probably bound to sulfhydryl-containing compounds. The proportion of amalgam particles in fecal samples from these individuals was low, and it did not exceed 26% of the total amount of mercury excreted.

Adult↗
PubMed2005

Bovine feces from animals with gastrointestinal infections are a source of serologically diverse atypical enteropathogenic Escherichia coli and Shiga toxin-producing E. coli strains that commonly possess intimin.

Shiga toxin-producing Escherichia coli (STEC) and enteropathogenic E. coli (EPEC) cells were isolated from 191 fecal samples from cattle with gastrointestinal infections (diagnostic samples) collected in New South Wales, Australia. By using a multiplex PCR, E. coli cells possessing combinations of stx1, stx2, eae, and ehxA were detected by a combination of direct culture and enrichment in E. coli (EC) (modified) broth followed by plating on vancomycin-cefixime-cefsulodin blood (BVCC) agar for the presence of enterohemolytic colonies and on sorbitol MacConkey agar for the presence of non-sorbitol-fermenting colonies. The high prevalence of the intimin gene eae was a feature of the STEC (35 [29.2%] of 120 isolates) and contrasted with the low prevalence (9 [0.5%] of 1,692 fecal samples possessed STEC with eae) of this gene among STEC recovered during extensive sampling of feces from healthy slaughter-age cattle in Australia (M. Hornitzky, B. A. Vanselow, K. Walker, K. A. Bettelheim, B. Corney, P. Gill, G. Bailey, and S. P. Djordjevic, Appl. Environ. Microbiol. 68:6439-6445, 2002). Forty-seven STEC serotypes were identified, including O5:H-, O8:H19, O26:H-, O26:H11, O113:H21, O157:H7, O157:H- and Ont:H- which are known to cause severe disease in humans and 23 previously unreported STEC serotypes. Serotypes Ont:H- and O113:H21 represented the two most frequently isolated STEC isolates and were cultured from nine (4.7%) and seven (3.7%) animals, respectively. Fifteen eae-positive E. coli serotypes, considered to represent atypical EPEC, were identified, with O111:H- representing the most prevalent. Using both techniques, STEC cells were cultured from 69 (36.1%) samples and EPEC cells were cultured from 30 (15.7%) samples, including 9 (4.7%) samples which yielded both STEC and EPEC. Culture on BVCC agar following enrichment in EC (modified) broth was the most successful method for the isolation of STEC (24.1% of samples), and direct culture on BVCC agar was the most successful method for the isolation of EPEC (14.1% samples). These studies show that diarrheagenic calves and cattle represent important reservoirs of eae-positive E. coli.

Adhesins, Bacterial↗
PubMed2003

Use of PCR for direct detection of Campylobacter species in bovine feces.

This study reports on the use of PCR to directly detect and distinguish Campylobacter species in bovine feces without enrichment. Inhibitors present in feces are a major obstacle to using PCR to detect microorganisms. The QIAamp DNA stool minikit was found to be an efficacious extraction method, as determined by the positive amplification of internal control DNA added to bovine feces before extraction. With nested or seminested multiplex PCR, Campylobacter coli, C. fetus, C. hyointestinalis, and C. jejuni were detected in all fecal samples inoculated at approximately 10(4) CFU g(-1), and 50 to 83% of the samples inoculated at approximately 10(3) CFU g(-1) were positive. At approximately 10(2) CFU g(-1), C. fetus, C. hyointestinalis, and C. jejuni (17 to 50% of the samples) but not C. coli were detected by PCR. From uninoculated bovine feces, a total of 198 arbitrarily selected isolates of Campylobacter were recovered on four commonly used isolation media incubated at three temperatures. The most frequently isolated taxa were C. jejuni (152 isolates) and C. lanienae (42 isolates), but isolates of C. fetus subsp. fetus, Arcobacter butzleri, and A. skirrowii also were recovered (</=2 isolates per taxon). Considerable variability was observed in the frequency of isolation of campylobacters among the four media and three incubation temperatures tested. With genus-specific primers, Campylobacter DNA was detected in 75% of the fecal samples, representing an 8% increase in sensitivity relative to that obtained with microbiological isolation across the four media and three incubation temperatures tested. With nested primers, C. jejuni and C. lanienae were detected in 25 and 67% of the samples, respectively. In no instance was DNA from either C. coli, C. fetus, or C. hyointestinalis detected in uninoculated bovine feces. PCR was more sensitive than isolation on microbiological media for detecting C. lanienae (17%) but not C. jejuni. Campylobacters are a diverse and fastidious group of bacteria, and the development of direct PCR not only will increase the understanding of Campylobacter species diversity and their frequency of occurrence in feces but also will enhance the knowledge of their role in the gastrointestinal tract of livestock and of the factors that influence shedding.

Animals↗
PubMed2003

Reverse transcription-PCR assays for detection of bovine enteric caliciviruses (BEC) and analysis of the genetic relationships among BEC and human caliciviruses.

Two genetically distinct bovine enteric caliciviruses (BECs) have been identified: the norovirus (NLV) Jena and Newbury Agent-2 (NA-2) BECs, which are genetically related to human noroviruses, and the Nebraska (NB) BECs, which is related to sapoviruses and lagoviruses but may also represent a new calicivirus genus. The prevalence of these two BEC genotypes in cattle is unknown. Although reverse transcription-PCR (RT-PCR) primers for human NLV recognize NLV-BECs, the genetic relationships between NLV from humans and the NLV-BECs commonly circulating in cattle is undefined. In the present study, veal calf fecal samples were assayed for enteric caliciviruses by using six RT-PCR primer sets designed for the detection of human NLVs or BECs. Caliciviruses genetically related to the NLV-BEC Jena and NA-2 strains or to the recently characterized NB BEC strain were identified in three of four and four of four sampled veal herds, respectively. Extended 3'-terminal genome sequences of two NLV-BECs, designated CV95-OH and CV186-OH, encoding the RNA-dependent RNA polymerase (RdRp; open reading frame 1 [ORF-1]), VP1 (ORF-2), and VP2 (ORF-3) genes were determined. Phylogenetic and sequence identity analyses of each genome region demonstrated these viruses to be most closely related to the NLV-BEC Jena and NA-2 strains. In initial testing, the human P289-P290 (P289/290) primer set was found to be the most sensitive for calicivirus detection. However, its failure to identify all positive fecal pools (as determined by other assays) led us to design two new primer sets, CBECU-F/R and NBU-F/R, for the sensitive and specific detection of NLV-BEC (NLV-BEC Jena and NA-2) and BEC-NB-like viruses, respectively. The RT-PCR assays with the new primers were compared against other primer sets, including P289/290. Composite results of the tests completed by using the new assays identified 72% (54 of 75) of veal calf fecal samples as positive, with 21 of 21 sequenced reaction products specific for the target RdRp gene. The same design strategy used for the new BEC assays may also be applicable to the design of similar assays for the detection of human caliciviruses (HuCVs). Our data support the genetic relationship between NLV-BECs and NLV-HuCVs but with the NLV-BECs comprising two clusters within a third NLV genogroup.

Animals↗
PubMed1986

[Viral and bacterial shedding in calves raised under commercial conditions].

Etiological, clinical, and epizootiological studies were carried out with newborn calves on two cow complexes of 500 animals each, raised under industrial conditions. Virologic and bacteriologic investigations of a total of 300 fecal samples taken from both calves and dams on the day of calving up to the 10th day as well as on the 20th and 30th day revealed that in 90 per cent of the cases there were rotaviruses. With calves that remained with the cows up to the 72nd hour 30 to 50 per cent of the rotaviruses were found from the second to the tenth day, and with calves that were separated from their dams immediately after calving rotaviruses were found at more advanced age too. Bacteriologically, as many as 92 strains of Escherichia coli were established as isolated from the fecal samples studied. Antigen K99 was demonstrated with 3.26 per cent of the strains. It was concluded that both with regard to the numbers of the E. coli strains isolated and to the period during which these were found the bacterium prevailed in calves that did not suck directly from their dams in the first days following calving.

Animals↗
PubMed1989

Distribution of persistent Salmonella typhimurium infection in internal organs of swine.

Experiments were conducted to establish a persistent Salmonella typhimurium infection in convalescent swine, and to determine rate of shedding and distribution of the organism in internal organs. Naturally farrowed Salmonella-free pigs (n = 37) were orally exposed to S typhimurium when 7 to 8 weeks old. Fecal samples, tonsillar scrapings, and rectal swab specimens were examined bacteriologically for S typhimurium at weekly intervals after exposure until necropsy (maximum of 28 weeks after exposure). Necropsies of 1 to 4 randomly selected pigs were conducted at 2, 4, and 7 days and at 2, 4, 6, 8, 12, 16, 20, 24, and 28 weeks after exposure. The following internal organs were examined bacteriologically for S typhimurium: liver, spleen, kidney, gallbladder, heart, lung, and stomach; segments of the intestinal tract with corresponding lymph nodes; lymph nodes from lymphocenters of the head and neck, thoracic and abdominal cavities, pelvic wall, and thoracic and pelvic limbs. Fecal samples were 83 to 100% culture-positive up to postexposure (PE) week 22, then varied from 14 to 67% positive until PE week 28. At least 60% of tonsillar swab specimens and 50% of rectal swab specimens were culture-positive up to PE week 20, after which they varied from 0 to 70% positive until PE week 28. At necropsy, S typhimurium was recovered most frequently from tonsils (93.5% positive), followed by segments of the intestinal tract from caudal portion of jejunum to rectum (71% recovery from cecum), and mandibular (54.8%) and ileocolic (45.2%) lymph nodes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

[Incidence and origin of Clostridium difficile in neonatology].

The epidemiology of Clostridium difficile was studied prospectively in 101 newborn infants by screening of fecal samples collected in the first or second day of life and in the fourth or fifth one. A vaginal swab and a stool specimen were collected from mothers before delivery. Environmental cultures were obtained from selected sites in the ward, while colonization of intestinal tract and contamination of the hands were evaluated in the personnel. C. difficile was isolated from the feces of 13 infants (13%); colonization rate was higher in infants delivered by cesarean section, but the difference was not significant. Intestinal carriage was demonstrated in two mothers (2%); the baby of one colonized mother was positive for C. difficile. All vaginal swabs were negative. Fecal samples of 2 nurses (18%) were positive; none of the environmental cultures yielded C. difficile. It was concluded that the mothers are not the sources of their infants' organisms and that the contamination of the environmental surfaces is the most likely explanation for the spread of C. difficile in the hospital setting.

Adult↗
PubMed1999

The use of avoparcin as a growth promoter and the occurrence of vancomycin-resistant Enterococcus species in Norwegian poultry and swine production.

This study documents a strong and statistically significant association between the use of the glycopeptide avoparcin as a growth promoter in Norwegian poultry production and the occurrence of vancomycin-resistant Enterococcus species (VRE). Avoparcin was approved as a feed additive for broilers and turkeys in Norway in 1986 and was banned from June 1, 1995. In a survey conducted in Norway between June, 1995 and March, 1997, VRE were isolated from fecal samples from 106 out of 109 poultry houses previously exposed to avoparcin (97%) and from six out of 33 poultry houses never exposed to avoparcin (18%) (RR = 5.35). Samples from previously exposed poultry houses were collected in three time periods. The proportion of positive samples remained high (96-98%), in all three time periods indicating a persistence of vancomycin resistance among enterococci for more than a year and a half after the withdrawal of avoparcin. VRE were also isolated from six out of 10 poultry farmers living on farms previously exposed to avoparcin, and from none of 16 farmers living on farms never exposed to avoparcin. Moreover, VRE were isolated from 68 out of the 225 broiler carcasses investigated (30%). The resistance to vancomycin was a high-level type (MIC > or = 256 microg/ml) mediated by the vanA gene. For comparison, VRE could only be isolated from two out of 147 fecal samples from Norwegian flocks of swine (1%). Because avoparcin never has been used in Norwegian swine production, this observation strengthens the association between the use of avoparcin in animal husbandry and the occurrence of VRE.

Animal Husbandry↗
PubMed2002

Transfer of the pheromone-inducible plasmid pCF10 among Enterococcus faecalis microorganisms colonizing the intestine of mini-pigs.

A new animal model, the streptomycin-treated mini-pig, was developed in order to allow colonization of defined strains of Enterococcus faecalis in numbers sufficient to study plasmid transfer. Transfer of the pheromone-inducible pCF10 plasmid between streptomycin-resistant strains of E. faecalis OG1 was investigated in the model. The plasmid encodes resistance to tetracycline. Numbers of recipient, donor, and transconjugant bacteria were monitored by selective plating of fecal samples, and transconjugants were subsequently verified by PCR. After being ingested by the mini-pigs, the recipient strain persisted in the intestine at levels between 10(6) and 10(7) CFU per g of feces throughout the experiment. The donor strain, which carried different resistance markers but was otherwise chromosomally isogenic to the recipient strain, was given to the pigs 3 weeks after the recipient strain. The donor cells were initially present in high numbers (10(6) CFU per g) in feces, but they did not persist in the intestine at detectable levels. Immediately after introduction of the donor bacteria, transconjugant cells appeared and persisted in fecal samples at levels between 10(3) and 10(4) CFU per g until the end of the experiment. These observations showed that even in the absence of selective tetracycline pressure, plasmid pCF10 was transferred from ingested E. faecalis cells to other E. faecalis organisms already present in the intestinal environment and that the plasmid subsequently persisted in the intestine.

Animals↗
PubMed2006

Models for estimating digesta passage kinetics in the gastrointestinal tract of the horse.

Fecal samples were collected to evaluate mathematical models to describe the kinetics of digesta passage in the segments of the equine gastrointestinal tract and to compare the passage kinetics of hay and oats. Four Norwegian Cold-blooded trotters (cecally cannulated, approximately 500 kg of BW) were fed Cr-mordanted hay and Yb-marked oats with their morning meal. The meal consisted of 2 kg of hay and 1 kg of oats processed as ground, pelleted, extruded, or micronized. Each horse was fed each type of oats on different days of collection, after a 5-d adaptation period, in a 4 x 4 Latin square design. Fecal samples were collected 5, 6, 7, 8, 9, 10, 11, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 48, and 52 h after administration of the marker dose. The samples were analyzed for Cr and Yb, and values were plotted using 1- and 2-compartment nonlinear passage models and an algebraic model. The 1-compartment G4 model and the 2-compartment G4G1 model showed an equally good fit to the observed excretion curves, based on low mean square error and SE. The excretion curves for hay (Cr) and oats (Yb) showed a striking similarity, and there seemed to be no difference in retention time between hay and oats in the horse. The mixing compartments in the horse are believed to be the cecum or both the cecum and the right ventral and dorsal segments of the colon, but further research in this area is needed to make a final conclusion.

Animal Feed↗