Forestomach Contents Research Articles

Isolation of Bacteria from Freeze-Dried Samples and the Functional Characterization of Species-Specific Lactic Acid Bacteria with a Comparison of Wild and Captive Proboscis Monkeys.

Previously, we isolated a novel lactic acid bacteria species (Lactobacillus nasalidis) from the fresh forestomach contents of a captive proboscis monkey (Nasalis larvatus) in a Japanese zoo. In this study, we isolated two strains of L. nasalidis from the freeze-dried forestomach contents of a wild proboscis monkey inhabiting a riverine forest in Malaysia. The samples had been stored for more than six years. Phenotypic analysis showed that strains isolated from the wild individual had more diverse sugar utilization and lower salt tolerance than strains previously isolated from the captive counterpart. These phenotypic differences are most likely induced by feeding conditions; wild individuals consume a wide variety of natural food, unlike their zoo-raised counterparts that consume formula feed with sodium sufficiency. Since 16s rRNA sequences of L. nasalidis were detected in the previously created 16S rRNA libraries of wild, provisioned, and captive proboscis monkeys in Malaysia and Japan, L. nasalidis may be an essential bacterium of the foregut microbial community of the proboscis monkey. The currently established method for the isolation of gut bacteria from freeze-dried samples under storage will be applicable to many already-stored precious samples.

A note on common minke whale (Balaenoptera acutorostrata) diets in the Norwegian Sea and the North Sea

Visual observations and quantitative samples of forestomach contents were made of minke whales caught in the Norwegian Sea (15 visual observations in 1999, 8 in 2000 and 1 stomach sample) and North Sea (15 visual observations and 7 stomach samples, all from 1999). Prey species were identified, and from the forestomach samples, each prey’s relative contribution by weight to the diet was calculated. In the Norwegian Sea, the diet was dominated by Norwegian spring-spawning herring (100%). This was consistent with the large and dominant abundance of herring in the area. Observations and forestomach samples from the North Sea indicated a more varied diet, with sandeel (Ammodytes spp.) contributing 86.7% to the diet by weight, followed by mackerel (9.3%), whiting (2.4%), herring (1.1%) and Norway pout (0.5%). Haddock was observed in one stomach, but was not found in any of the samples. Sandeel occurred in all observed and four of the sampled stomachs. The domination of pelagic species in the diet strongly indicates pelagic feeding behaviour in both areas.

Relative abundance and size composition of prey in the common minke whale diet in selected areas of the northeastern Atlantic during 2000-04

A total of 210 common minke whales (Balaenoptera acutorostrata) were sampled in five different areas in the northeastern Atlantic during May-June 2000-04. Analysis of forestomach contents revealed a relatively mixed diet at the population level, whereas on an individual level, each whale had fed upon mainly one species. There were significant differences in diet composition between areas and some differences between years. The importance of krill in the Barents Sea increased with latitude and krill dominated the Spitsbergen diet. Capelin dominated the diet around Bear Island and contributed considerably to the diet along the coast of northern Norway. In the latter area, herring and haddock were also a great part of the diet. The diet in the Norwegian Sea consisted of mainly mature herring, while the diet in the North Sea was dominated by sand eels and mackerel. The minke whales were found to feed on a wide range of prey sizes, apparently determined by the availability of different size classes.

Scaling at different ontogenetic stages: Gastrointestinal tract contents of a marsupial foregut fermenter, the western grey kangaroo Macropus fuliginosus melanops

Prominent ontogenetic changes of the gastrointestinal tract (GIT) should occur in mammals whose neonatal diet of milk differs from that of adults, and especially in herbivores (as vegetation is particularly distinct from milk), and even more so in foregut fermenters, whose forestomach only becomes functionally relevant with vegetation intake. Due to the protracted lactation in marsupials, ontogenetic differences can be particularly well investigated in this group. Here, we report body mass (BM) scaling relationships of wet GIT content mass in 28 in-pouch young (50 g to 3 kg) and 15 adult (16–70 kg) western grey kangaroos Macropus fuliginosus melanops. Apart from the small intestinal contents, in-pouch young and adults did not differ in the scaling exponents (‘slope’ in log-log plots) but did differ in the scaling factor (‘intercept’), with an implied substantial increase in wet GIT content mass during the out-of-pouch juvenile period. In contrast to forestomach contents, caecum contents were elevated in juveniles still in the pouch, suggestive of fermentative digestion of milk and intestinal secretion residues, particularly in the caecum. The substantial increase in GIT contents (from less than 1 to 10–20% of BM) was associated mainly with the increase in forestomach contents (from 25 to 80% of total GIT contents) and a concomitant decrease in small intestine contents (from 50 to 8%), emphasizing the shifting relevance of auto-enzymatic and allo-enzymatic (microbial) digestion. There was a concomitant increase in the contents-to-tissue ratio of the fermentation chambers (forestomach and caecum), but this ratio generally did not change for the small intestine. Our study not only documents significant ontogenetic changes in digestive morpho-physiology, but also exemplifies the usefulness of intraspecific allometric analyses for quantifying these changes.

Individual differences in behaviour and gut bacteria are associated in collared peccary (Mammalia, Tayassuidae).

We tested the hypothesis that the behaviour of an individual is associated with the diversity of its gut bacteria, using the collared peccary (Pecari tajacu) as a model. In all, 24 adult male collared peccaries received either low- (n = 12) or high-fibre diet (n = 12) to induce contrasting gut fermentation profiles. They were submitted to three short-term challenges, allowing us to rate the animals in a coping-style dimension named 'calmness'. At the end of the experimental period, we collected samples of peccaries' forestomach contents to characterize bacterial diversity. We found a significant positive association between individual 'calmness' z-scores and the bacterial evenness index in gut bacteria (and a similar trend with the Simpson's diversity index), suggesting a more homogeneous bacterial community of calmer individuals. We also found a positive association between fibres digestibility and gut bacterial diversity in the peccaries' forestomach, but no effect of the dietary fibre level. Gut bacteria evenness increases with 'calmness' z-scores, suggesting a more homogeneous bacterial community of calmer individuals, compared with the more heterogeneous of the most distressed ones. Our results also suggest associations between the digestibility of ADF with the gut bacterial diversity indices and with the relative abundance of the Actinobacteria phylum. Our data showed that the hosts' individual behavioural differences are potentially aligned with gut bacterial diversity. The behaviour-microbiota link is correlated with host feed efficiency and, ultimately, may have implications for animal health and welfare of farm animals.

Lactobacillus nasalidis sp. nov., isolated from the forestomach of a captive proboscis monkey (Nasalis larvatus).

Three strains (YZ01T, YZ02 and YZ03) of Gram-stain-positive, facultatively anaerobic rods were isolated from the forestomach contents collected from a captive male proboscis monkey (Nasalis larvatus) at Yokohama Zoo in Japan. Phylogenetic analysis of the 16S rRNA gene sequences revealed that these strains belonged to the genus Lactobacillus. Based on the sequence similarity of the 16S rRNA gene, Lactobacillus delbrueckii subsp. indicus JCM 15610T was the closest phylogenetic neighbour to YZ01T. Sequence analyses of two partial concatenated housekeeping genes, the RNA polymerase alpha subunit (rpoA) and phenylalanyl-tRNA synthase alpha subunit (pheS) also indicated that the novel strains belonged to the genus Lactobacillus. The average nucleotide identity and digital DNA-DNA hybridization (dDDH) between L. delbrueckii subsp. indicus and YZ01T were 85.9 and 31.4 %, respectively. The phylogenetic tree based on the whole genomic data of strains YZ01T, YZ02 and YZ03 suggested that these three strains formed a single monophyletic cluster in the genus Lactobacillus, indicating that it belonged to a new species. The DNA G+C content of strain YZ01T was 51.6 mol%. The major fatty acids were C16 : 0 and C18 : 1 ω9c. Therefore, based on phylogenetic, phenotypic and physiological evidence, strains YZ01T, YZ02 and YZ03 represent a novel species of the genus Lactobacillus, for which the name Lactobacillus nasalidis sp. nov. is proposed with the type strain YZ01T (=JCM 33769T=DSM 110539T).

Physical characteristics of forestomach contents from two nondomestic small ruminants, the blackbuck (Antilope cervicapra) and the Arabian sand gazelle (Gazella subgutturosa marica)

Rumen content stratification and the degree of dissociation of particle and fluid retention in the reticulorumen differ between ‘moose-type’ and ‘cattle-type’ ruminant species. These differences are not strictly linked to diet, except for a seeming limitation of ‘moose-type’ ruminants to a browsing niche. Nevertheless, these differences can be plausibly linked to other observed differences in ruminants, such as the intraruminal papillation pattern, or the size of the omasum. However, many of the corresponding measures are still only available for a restricted number of species. Here, we investigated the dry matter (i.e., the inverse of the moisture) concentration in forestomach contents of 10 blackbuck (Antilope cervicapra) and 7 Arabian sand gazelle (Gazella subgutturosa marica), and quantified the rumen papillation pattern. The blackbucks had distinct rumen contents stratification, with more moisture in ventral than in dorsal contents (difference 3.6% units, P < 0.001), whereas this difference was much less pronounced in the sand gazelles (0.6% units, P = 0.227). While reticulum contents were particularly moist in both species, omasum contents were particularly dry in sand gazelles, but did not differ in moisture from rumen contents in the blackbuck. This species is an outlier among ruminants due to its extremely small omasum. The intraruminal papillation pattern did not differ between blackbucks and sand gazelles and showed a surface enlargement factor (SEF) in the dorsal rumen of 27–28% of the SEF in the Atrium ruminis. Compared to data on digesta retention in the same species, the findings are in line with the overall concept of a high fluid throughput causing a distinct stratification of rumen contents and intraruminal papillation, and necessitating a large omasum for fluid re-absorption. However, the data also show that individual species may not correspond to all the assumptions of the concept, suggesting taxon-specific differences between species. Reasons for these differences cannot be linked to a dietary grass-browse spectrum, but may lie in evolutionary contingency.

Endosymbiotic Ciliated Protozoan Biota of Dromedary Camels and Domestic Cattle in Tunisia.

Species concentration and composition of endosymbiotic ciliates were investigated in the forestomach contents of 12 dromedary camels (Camelus dromedarius) and the ruminal contents of 16 domestic cattle (Bos taurus taurus) living in Ben Gardane, Tunisia. Sixteen species and 8 morphotypes, belonging to 8 genera, were identified from dromedary camels, and 18 species and 13 morphotypes, belonging to 8 genera, were identified from domestic cattle. This is the first report on the endosymbiotic ciliated protozoan biota of dromedary camels and cattle living in Tunisia. The mean density (± SD) of ciliates in the forestomach samples of dromedary camels and the ruminal samples of domestic cattle was 65.4 ± 69.4 × 104 cells mL-1 and 54.2 ± 55.8 × 104 cells mL-1, respectively. Diplodinium cameli and Blepharoconus krugerensis were detected for the first and second time, respectively, from the ruminal contents of cattle. Caloscolex camelinus and B. krugerensis were studied in detail with a scanning electron microscope.

Ciliated Protozoan Fauna in the Forestomach of Dromedary Camels (Camelus dromedarius) in Libya.

Species composition and distribution of ciliated protozoa obtained from the forestomach of 20 dromedary camels living in Zawiya, Libya were examined. Nineteen species and 10 morphotypes belonging to eight genera were identified. The mean number of ciliates was 54.2 ± 32.9 × 104 cells ml-1 in the forestomach contents, and the mean number of ciliate species per host was 6.5 ± 2.9. Entodinium and Epidinium were the main genera, as these ciliates were found consistently at higher proportions than those of the other genera. In contrast, Ophryoscolex and Polyplastron were only observed at low frequencies. Diplodinium rangiferi, Entodinium ellipsoideum, E. simulans, and Polyplastron multivesiculatum were new endosymbionts recorded from camels.

Differences down-under: alcohol-fueled methanogenesis by archaea present in Australian macropodids.

The Australian macropodids (kangaroos and wallabies) possess a distinctive foregut microbiota that contributes to their reduced methane emissions. However, methanogenic archaea are present within the macropodid foregut, although there is scant understanding of these microbes. Here, an isolate taxonomically assigned to the Methanosphaera genus (Methanosphaera sp. WGK6) was recovered from the anterior sacciform forestomach contents of a Western grey kangaroo (Macropus fuliginosus). Like the human gut isolate Methanosphaera stadtmanae DSMZ 3091(T), strain WGK6 is a methylotroph with no capacity for autotrophic growth. In contrast, though with the human isolate, strain WGK6 was found to utilize ethanol to support growth, but principally as a source of reducing power. Both the WGK6 and DSMZ 3091(T) genomes are very similar in terms of their size, synteny and G:C content. However, the WGK6 genome was found to encode contiguous genes encoding putative alcohol and aldehyde dehydrogenases, which are absent from the DSMZ 3091(T) genome. Interestingly, homologs of these genes are present in the genomes for several other members of the Methanobacteriales. In WGK6, these genes are cotranscribed under both growth conditions, and we propose the two genes provide a plausible explanation for the ability of WGK6 to utilize ethanol for methanol reduction to methane. Furthermore, our in vitro studies suggest that ethanol supports a greater cell yield per mol of methane formed compared to hydrogen-dependent growth. Taken together, this expansion in metabolic versatility can explain the persistence of these archaea in the kangaroo foregut, and their abundance in these 'low-methane-emitting' herbivores.

Ciliate protozoa of the forestomach of llamas (Lama glama) from locations at different altitude in Argentina.

This study describes the diversity and concentration of the protozoal population from the forestomach of llamas in Argentina at three altitudinal locations. Protozoal diversity was studied in samples from eight llamas from Hurlingham (Buenos Aires, 43 m altitude), four from Tilcara (Jujuy, 2465 m altitude) and six llamas from Cieneguillas (Jujuy, 3800 m altitude). The total concentrations of protozoa in the forestomach contents were 7.9, 9.1 and 4.1 cells x 10⁴ ml^-1 in Hurlingham, Tilcara and Cieneguillas, respectively (P&gt;0.05). Entodinium spp. represented 97.9, 92.3 and 71.4% of the protozoal community in Hurlingham, Tilcara and Cieneguillas, respectively, and the remaining protozoa belonged to the Eudiplodinium genus. Entodinium spp. were identified as E. caudatum (mostly morphotype dubardi), E. longinucleatum, E. parvum, E. bovis, E. exiguum, E. dubardi, and a minor presence of E. bimastus (in three animals) and E. ovibos (in one animal). In regards to the rest of protozoal species, Eudiplodinium maggii is the first reported host record for the genus in llamas. This species was present in the forestomach of 14 out of 18 llamas tested, and in one case it was the unique protozoal species. The vestibuliferids, Dasytricha and Isotricha were absent from the forestomach of llamas. Similarly, other species such as those from the Caloscolex genus, Diplodinium cameli and Entodinium ovumrajae, commonly found in Old World Camelids, were also absent from llamas.

Investigation of a new acetogen isolated from an enrichment of the tammar wallaby forestomach.

BackgroundForestomach fermentation in Australian marsupials such as wallabies and kangaroos, though analogous to rumen fermentation, results in lower methane emissions. Insights into hydrogenotrophy in these systems could help in devising strategies to reduce ruminal methanogenesis. Reductive acetogenesis may be a significant hydrogen sink in these systems and previous molecular analyses have revealed a novel diversity of putative acetogens in the tammar wallaby forestomach.ResultsMethanogen-inhibited enrichment cultures prepared from tammar wallaby forestomach contents consumed hydrogen and produced primarily acetate. Functional gene (formyltetrahydrofolate synthetase and acetyl-CoA synthase) analyses revealed a restricted diversity of Clostridiales species as the putative acetogens in the cultures. A new acetogen (growth on H2/CO2 with acetate as primary end product) designated isolate TWA4, was obtained from the cultures. Isolate TWA4 classified within the Lachnospiraceae and demonstrated >97% rrs identity to previously isolated kangaroo acetogens. Isolate TWA4 was a potent hydrogenotroph and demonstrated excellent mixotrophic growth (concomitant consumption of hydrogen during heterotrophic growth) with glycerol. Mixotrophic growth of isolate TWA4 on glycerol resulted in increased cell densities and acetate production compared to autotrophic growth. Co-cultures with an autotrophic methanogen Methanobrevibacter smithii revealed that isolate TWA4 performed reductive acetogenesis under high hydrogen concentration (>5 mM), but not at low concentrations. Under heterotrophic growth conditions, isolate TWA4 did not significantly stimulate methanogenesis in a co-culture with M. smithii contrary to the expectation for organisms growing fermentatively.ConclusionsThe unique properties of tammar wallaby acetogens might be contributing factors to reduced methanogen numbers and methane emissions from tammar wallaby forestomach fermentation, compared to ruminal fermentation. The macropod forestomach may be a useful source of acetogens for future strategies to reduce methane emissions from ruminants, particularly if these strategies also include some level of methane suppression and/or acetogen stimulation, for example by harnessing mixotrophic growth capabilitiesElectronic supplementary materialThe online version of this article (doi:10.1186/s12866-014-0314-3) contains supplementary material, which is available to authorized users.

Microbial diversity in forestomach and caecum contents of the greater long-tailed hamster Tscherskia triton (Rodentia: Cricetidae)

The mammalian gastrointestinal tract has evolved to facilitate food utilisation. Hamsters within the subfamily Cricetinae (Rodentia, Cricetidae) have a compartmentalised stomach consisting of a forestomach and a glandular stomach. The role of the forestomach in hamsters has long been discussed. In this study, we evaluated the microflora and volatile fatty acid contents of the large forestomach and caecum of a greater long-tailed hamster (Tscherskia triton). The estimated bacterial biodiversity in the forestomach based on 16S rRNA library sequencing analyses was low (sequence n=226, Shannon index H′=2.12) compared to that in the rumen of ruminants. In contrast, the bacterial diversity in the caecum was very high (n=259, H′=4.45), and comparable to that of other hindgut fermenters. The forestomach bacterial flora was dominated by Lactobacillus spp. (179/226 clones), and high concentrations of lactic acid were observed in the forestomach. These results indicate that the forestomach does not function like the rumen of ruminants, but that lactic acid fermentation does take place in this compartment. The caecum is thought to play a more important role in food digestion via fermentation by symbiotic microbes than the forestomach. When all cloned 16S rRNA gene sequences (n=485) were grouped into operational taxonomic units (OTUs) with 97% similarity, the majority of clones isolated from the forestomach contents were also present in the caecum (85.4%), although fewer clones isolated from the caecum contents shared OTUs with clones from the forestomach (19.3%). Based on these results, we hypothesise that bacteria were transferred from the caecum to the forestomach by coprophagy.

Detection of fiber-digesting bacteria in the forestomach contents of llamas (Lama glama) by PCR

The high fibrolytic activity and large biomass of strictly-anaerobic bacteria that inhabit the rumen makes them primarily responsible for the degradation of the forage consumed by ruminants. Llamas feed mainly on low quality fibrous roughages that are digested by an active and diverse microflora. The products of this fermentation are volatile fatty acids and microbial biomass, which will be used by the animals. The aim of this study was to detect the three major fiber-digesting anaerobic bacteria in the forestomach contents of llamas by PCR. In this study, we detected Ruminococcus albus, Ruminococcus flavefaciens and Fibrobacter succinogenes in the forestomach contents of eight native llamas from Argentina.

Forestomach pH in hunted roe deer (Capreolus capreolus) in relation to forestomach region, time of measurement and supplemental feeding and comparison among wild ruminant species

There is a debate whether supplemental feeding of deer bears the risk of inducing health problems, in particular acidosis. Here, the pH values of forestomach contents of free-ranging roe deer (Capreolus capreolus) shot in areas with and without supplemental winter feeding were compared. pH was similar in the dorsal and ventral rumen, but lower at these sites than in the Atrium ruminis, where it was again lower than in the reticulum; this pattern corresponds to expectations based on differences in the presence of saliva at the different sites of the forestomach. pH was lower with increasing time that elapsed between death of the animal and measuring pH in unsupplemented animals and was lower in unsupplemented animals in May/June than later in the year. Animals with supplemental winter feeding had significantly lower rumen pH (5.5) than animals without food supplementation (5.7). These data suggest that supplemental feeding of roe deer has the potential to lower forestomach pH. Although pH values measured in supplemented animals in this study would be considered indicative of rumen acidosis in domestic cattle, they are within the range previously measured in various free-ranging Odocoilid species, including roe deer; were of a similar magnitude as the May/June values of unsupplemented roe deer in this study; and must be considered with respect to potentially rapid declines in pH between death of the animal and pH measurement. Given methodological problems, analyses of literature data from free-ranging wild ruminants provide little evidence for a systematic variation of rumen pH with feeding type and body mass, but lead to the hypothesis that some New World cervids, including the roe deer, might either naturally have lower pH values than other ruminants or rumen contents whose pH drops rapidly after death.

Archaea in the foregut of macropod marsupials: PCR and amplicon sequence-based observations

To investigate, using culture-independent techniques, the presence and diversity of methanogenic archaea in the foregut of kangaroos. DNA was extracted from forestomach contents of 42 kangaroos (three species), three sheep and three cattle. Four qualitative and quantitative PCR assays targeting the archaeal domain (16S rRNA gene) or the functional methanogenesis gene, mcrA, were used to determine the presence and population density of archaea in kangaroos and whether they were likely to be methanogens. All ruminal samples were positive for archaea, produced PCR product of expected size, contained high numbers of archaea and high numbers of cells with mcrA genes. Kangaroos were much more diverse and contradictory. Fourteen kangaroos had detectable archaea with numbers 10- to 1000-fold fewer than sheep and cattle. Many kangaroos that did not possess archaea were positive for the mcrA gene and had detectable numbers of cells with this gene and vice versa. DNA sequence analysis of kangaroos' archaeal 16S rRNA gene clones show that many methanogens were related to Methanosphaera stadmanae. Other sequences were related to non-methanogenic archaea (Thermoplasma sp.), and a number of kangaroos had mcrA gene sequences related to methane oxidising archaea (ANME). Discrepancies between qualitative and quantitative PCR assays for archaea and the mcrA gene suggest that the archaeal communities are very diverse and it is possible that novel species exist. Archaea (in general) were below detectable limits in many kangaroos, especially Red kangaroos; when present they are in lower numbers than in ruminants, and the archaea are not necessarily methanogenic. The determination of why this is the case in the kangaroo foregut could assist in reducing emissions from other ecosystems in the future.

Physical characteristics of rumen contents in two small ruminants of different feeding type, the mouflon ( Ovis ammon musimon) and the roe deer ( Capreolus capreolus)

In domestic ruminants, the stratification of forestomach contents – the results of flotation and sedimentation processes – is an important prerequisite for the selective particle retention in this organ. A series of anatomical and physiological measurements suggests that the degree of this stratification varies between browsing and grazing wild ruminants. We investigated the forestomach contents of free-ranging mouflon and roe deer shot during regular hunting procedures. There was no difference between the species in the degree by which forestomach ingesta separated according to size due to buoyancy characteristics in vitro. However, forestomach fluid of roe deer was more viscous than that of mouflon, and no difference in moisture content was evident between the dorsal and the ventral rumen in roe deer, in contrast to mouflon. Hence, the forestomach milieu in roe deer appears less favourable for gas or particle separation due to buoyancy characteristics. These findings are in accord with notable differences in forestomach papillation between the two species. In roe deer, particle separation is most likely restricted to the reticulum, whereas in mouflon, the whole rumen may pre-sort particles to a higher degree. The results suggest that differences in forestomach physiology may occur across ruminant species.

Physical characteristics of rumen contents in four large ruminants of different feeding type, the addax ( Addax nasomaculatus), bison ( Bison bison), red deer ( Cervus elaphus) and moose ( Alces alces)

Based on morphological and physiological observations, it has been suggested that differences exist in the degree that reticuloruminal (RR) contents are stratified between various ruminant species. However, the occurrence of stratification has hardly been measured in non-domestic species. Forestomach contents of free-ranging moose ( n = 22) and red deer (24) shot during regular hunting procedures, and of captive (but 100% forage fed) addax (6) and bison (10) culled for commercial or management purposes were investigated. There was no difference between the species in the degree by which RR ingesta separated according to size due to buoyancy characteristics in vitro. However, RR fluid of moose was more viscous than that of the other species, and no difference in moisture content was evident between the dorsal and the ventral rumen in moose, in contrast to the other species. Hence, the RR milieu in moose appears less favourable for gas or particle separation due to buoyancy characteristics. These findings are in accord with notable differences in RR papillation between the species. In moose, particle separation is most likely restricted to the reticulum, whereas in the other species, the whole rumen may pre-sort particles in varying degrees; a possible explanation for this pattern is a hypothetically lesser saliva production and fluid throughput in moose. The results suggest that differences in RR physiology may occur across ruminant species. The RR sorting mechanism should be considered a dynamic process that is better measured by its result — the significantly smaller particle size in the distal digestive tract when compared to the RR — than by regional differences in particle size within the RR.

Investigations on the stratification of forestomach contents in ruminants: an ultrasonographic approach

The degree of stratification in the reticulorumen contents is considered a major explanatory factor for other morphological and physiological differences between ruminant feeding types. However, information on reticulorumen (RR) contents is usually gathered from dead animals or indirect such as passage kinetics. We hypothesized that, although the contents of the gastrointestinal tract can usually not be evaluated by ultrasonography, the three typical layers of stratified RR contents (gas dome, fibre mat, fluid) can be demonstrated by this technique. In three domestic cows, the gas dome in the cows’ rumens could be demonstrated sonographically by reverberation lines running in parallel to the line demarcating the rumen mucosa, as is typical for the sonographic image of large, gas-filled spaces. More ventrally, the area behind the rumen mucosa showed typical pattern indicating gaseous inclusions, corresponding to the fibre mat inside the rumen. Further ventrally, in two of the animals, the area behind the demarcation line appeared dark without reverberation lines, as is typical for large fluid-filled spaces. When the technique was applied to a captive, habituated, browse-fed moose, no gas dome could be demonstrated, supporting the hypothesis that the reticulorumen contents of browsers are less stratified. The results of this study indicate that sonography represents a useful tool for the demonstration of RR contents stratification in live animals.

Spontaneous poisoning by larvae of Perreyia flavipes (Pergidae) in sheep

From a flock of 175 Texel sheep 25 animals died after consumption of a sawfly larvae subsequently identified as Perreyia flavipes. The disease occurred in June-July 2006 on a farm located in the county of Encruzilhada do Sul, Rio Grande do Sul, Brazil. Although there were 11 cattle in the same paddock, none of them was affected. High numbers of compact masses containing up to 150 larvae were scattered in the paddock where the animals were grazing. Most affected sheep showed severe apathy during 24-36 h before death, but weakness, muscular tremors and depression were also observed. Necropsy was performed on six sheep and the main macroscopic lesions were hemorrhages in the subcutaneous tissues, endocardium, gallbladder wall, and abomasal mucosa. In all animals was found hydrothorax, hydropericardium, ascites, and mild jaundice. Edema in the abomasal folds, mesentery, perirenal tissues, and gallbladder wall were also seen. The livers were yellowish with disseminated pinpoint hemorrhages in the parenchyma and had an enhanced lobular pattern. Perreyia flavipes larval body fragments and heads were found in the forestomach contents of the six sheep. Feces were scant, dry and formed balls coated by mucus and streaks of blood. Similar contents were also present at the end of the cecum. Prominent microscopic lesions included severe and diffuse periacinar or massive necrosis of hepatocytes associated with multifocal random hemorrhages. Diffuse necrosis of lymphoid follicles in lymph nodes and Peyer's patches, lymphoid depletion and necrosis in germinative centers of the spleen, and diffuse vacuolization in the renal tubular epithelia were also seen.