Forestomach Fluid Research Articles

Determination of hematobiochemical and fore stomach fluid constituents of llama (Lama glama) living in Egypt

There are no available data regarding the hematology, serum biochemistry, and fore stomach fluid constituents of llama (Lama glama) in Egypt. This study aimed to establish normal reference values for blood and fore stomach fluid constituents of llama and determine the influence of sex and season on these parameters under Egyptian conditions. The study was performed on (n = 38; 22 female, 16 male; 1–7 years) apparently healthy llamas located in the Giza Zoo and private zoo in the Ismailia Governorate. Samples were collected in two seasons and divided into summer and winter samples. Differences in the mean and range values of packed cell volume, serum minerals, fore stomach fluid pH, and total protozoal count in Egypt were recorded. Sex and season had minimal effects on hematology and only erythrocyte count showed a significant (p < 0.05) increase in males compared with females. Regarding serum biochemistry, males showed significant (p < 0.05) increases in alanine transaminase and calcium levels, while globulin significantly (p < 0.05) increased in females. The influence of season on serum biochemistry was evident in alanine transaminase, total protein, albumin, and chloride which increased significantly (p < 0.05) in summer, while urea, bilirubin, and magnesium increased significantly (p < 0.05) in winter. Fore stomach fluid pH and ammonia showed significant (p < 0.05) increases in winter, while the total protozoal count increased significantly (p < 0.05) in summer and in males compared with females. The results obtained in this study can serve as reference values for the hematobiochemical and fore stomach fluid constituents of llama in Egypt.

Composition of the microbiota in forestomach fluids and feces of Japanese Black calves with white scours1

The objective of this study was to characterize the composition of the forestomach and fecal microbiota in Japanese Black calves with white scours. Forestomach fluid, feces, and peripheral blood were collected from healthy calves (n = 5; age 10 ± 2 d) and scouring calves (n = 5; age 10 ± 1 d) on the day on which white scours occurred. The pH and concentrations of VFA, lactic acid, and ammonia nitrogen (NH3–N) of the forestomach fluids were determined. Microbiota composition and gene copy numbers in the forestomach fluid and feces were analyzed by 454 pyrosequencing and quantitative real-time PCR (qPCR), respectively. The cytokine mRNA level in peripheral leukocytes was evaluated by qPCR. The pH of the forestomach fluid of the scouring calves tended to be higher than that of the healthy calves (P = 0.056). No significant difference was detected in the total VFA, lactic acid, or NH3–N concentrations in the forestomach fluids of the 2 groups. Firmicutes, Bacteroidetes, and Proteobacteria were the predominant phyla in the forestomach fluid and feces. At the genus level, the relative abundance of Oscillibacter in the forestomach fluid was significantly higher in the scouring calves (P < 0.05) and the relative abundance of Faecalibacterium in the feces was significantly higher than that in the forestomach in the healthy calves (P < 0.05). Furthermore, the bacterial diversity indices of feces were lower in the scouring calves. Quantitative PCR amplification using some of the primer pairs failed in the forestomach fluid and feces in both groups. These results suggested that fermentation in the forestomach may affect the occurrence of white scours, resulting in changes in the composition and diversity of the forestomach fluid and fecal microbiota in Japanese Black calves.

Physiological adaptations of ruminants and their potential relevance for production systems

ABSTRACT Herbivores face the dilemma that the level of feed intake is negatively related to factors that determine digestive efficiency, such as thoroughness of ingesta comminution by chewing, and retention of digesta in the digestive tract. Ruminants have evolved particular adaptations to solve this dilemma. Most ruminants share the characteristic of “digesta washing”: fluid moves through their digestive tract faster than particles, thus effectively washing very fine particles, such as bacteria, out of the digesta plug. As the forestomach is followed by auto-enzymatic digestion, this allows a continuous, increased harvest of microbes from the forestomach. True rumination only evolved twice, in the camelids and the true ruminants. These both evolved a density-dependent sorting mechanism based on physical separation of the digesta by the process of flotation and sedimentation, ensuring that the process of rumination is applied to large particles. Differences in this sorting mechanism might facilitate a faster digesta processing in true ruminants as compared with camelids. The hallmark of ruminant digestive anatomy is the omasum, in which the fluid required for both digesta washing and the reticular separation mechanism is re-absorbed. In ruminants of the tribe Bovini, the omasum has reached the largest size and this group has a particularly great forestomach fluid throughput. Increasing the degree of digesta washing even more should increase microbial harvest from the forestomach and reduce the susceptibility to acidosis. At the same time, it should result in a metabolic state of the microbiome more tuned towards biomass production and less towards methanogenesis. Enhancing the forestomach fluid throughput by selective breeding could represent a promising way to further advance the productivity of the ruminant digestive tract.

Composition of the microbiota in forestomach fluids and feces of Japanese Black calves with white scours.

The objective of this study was to characterize the composition of the forestomach and fecal microbiota in Japanese Black calves with white scours. Forestomach fluid, feces, and peripheral blood were collected from healthy calves ( = 5; age 10 ± 2 d) and scouring calves ( = 5; age 10 ± 1 d) on the day on which white scours occurred. The pH and concentrations of VFA, lactic acid, and ammonia nitrogen (NH-N) of the forestomach fluids were determined. Microbiota composition and gene copy numbers in the forestomach fluid and feces were analyzed by 454 pyrosequencing and quantitative real-time PCR (qPCR), respectively. The cytokine mRNA level in peripheral leukocytes was evaluated by qPCR. The pH of the forestomach fluid of the scouring calves tended to be higher than that of the healthy calves ( = 0.056). No significant difference was detected in the total VFA, lactic acid, or NH-N concentrations in the forestomach fluids of the 2 groups. Firmicutes, Bacteroidetes, and Proteobacteria were the predominant phyla in the forestomach fluid and feces. At the genus level, the relative abundance of in the forestomach fluid was significantly higher in the scouring calves ( < 0.05) and the relative abundance of in the feces was significantly higher than that in the forestomach in the healthy calves ( < 0.05). Furthermore, the bacterial diversity indices of feces were lower in the scouring calves. Quantitative PCR amplification using some of the primer pairs failed in the forestomach fluid and feces in both groups. These results suggested that fermentation in the forestomach may affect the occurrence of white scours, resulting in changes in the composition and diversity of the forestomach fluid and fecal microbiota in Japanese Black calves.

Microbial Community in the Forestomachs of Alpacas (Lama pacos) and Sheep (Ovis aries)

Four 2-yr old alpacas ((48±2.3) kg) and four 2-yr old sheep ((50±1.7) kg) were used to study the pH and microbial community of forestomach from alpacas (Lama pacos) and sheep (Ovis aries) fed fresh alfalfa as the sole forage at low altitude (793 m). The forestomach fluid was taken anaerobically via the esophagus. The electric pH meter and quantitative polymerase chain reaction systems were used to study the the pH and microbial community of forestomach. The results showed that the mean pH of forestomach fluid from alpacas was higher than that from sheep (P<0.01). The percentages of methanogens and Ruminococcus flavefaciens to total bacterial were lower in the forestomach of alpacas than that in the rumen of sheep, while the percentage of fungi and Fibrobacter succinogenes were higher. The percentage of protozoa was similar in the forestomach of alpacas and sheep. These differences can partly explain the reason that alpacas were lower methane production than sheep.

Molecular analysis of the bacterial microbiome in the forestomach fluid from the dromedary camel (Camelus dromedarius)

Rumen microorganisms play an important role in ruminant digestion and absorption of nutrients and have great potential applications in the field of rumen adjusting, food fermentation and biomass utilization etc. In order to investigate the composition of microorganisms in the rumen of camel (Camelus dromedarius), this study delves in the microbial diversity by culture-independent approach. It includes comparison of rumen samples investigated in the present study to other currently available metagenomes to reveal potential differences in rumen microbial systems. Pyrosequencing based metagenomics was applied to analyze phylogenetic and metabolic profiles by MG-RAST, a web based tool. Pyrosequencing of camel rumen sample yielded 8,979,755 nucleotides assembled to 41,905 sequence reads with an average read length of 214 nucleotides. Taxonomic analysis of metagenomic reads indicated Bacteroidetes (55.5 %), Firmicutes (22.7 %) and Proteobacteria (9.2 %) phyla as predominant camel rumen taxa. At a finer phylogenetic resolution, Bacteroides species dominated the camel rumen metagenome. Functional analysis revealed that clustering-based subsystem and carbohydrate metabolism were the most abundant SEED subsystem representing 17 and 13 % of camel metagenome, respectively. A high taxonomic and functional similarity of camel rumen was found with the cow metagenome which is not surprising given the fact that both are mammalian herbivores with similar digestive tract structures and functions. Combined pyrosequencing approach and subsystems-based annotations available in the SEED database allowed us access to understand the metabolic potential of these microbiomes. Altogether, these data suggest that agricultural and animal husbandry practices can impose significant selective pressures on the rumen microbiota regardless of rumen type. The present study provides a baseline for understanding the complexity of camel rumen microbial ecology while also highlighting striking similarities and differences when compared to other animal gastrointestinal environments.

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.

Feed intake, forestomach fluid volume, dilution rate and mean retention of fluid in the forestomach during water deprivation and rehydration in camels ( Camelus sp.)

Camels were deprived of water for 11 days. Before and during water deprivation and during rehydration changes in body weight, feed and water intake were measured. Using the liquid marker Cr-EDTA forestomach fluid volume, mean fluid retention and fluid dilution in the forestomach were estimated. At the eleventh day of water deprivation hay intake had decreased to only 9.6% of controls, dilution rates had decreased to 31%, mean retention time of fluid in the forestomach had increased to 189%. At the end of dehydration flow of saliva of 2 l/h mainly contributed to the still rather high dilution rates. Thereby buffering capacity and flow of fluid into the forestomach for microbial digestion as well as the outflow from the forestomach were maintained. At the beginning of rehydration camels drank 97 l within a few minutes, and animals thereby replaced all the water lost. Following this first huge water intake water is rapidly absorbed from the forestomach, and forestomach volume decreased again to dehydration values. At the third day of rehydration control values were reached again. Although feed intake decreased dramatically during water deprivation, functions of the forestomach can be maintained sufficiently mainly due to saliva inflow. This explains the mostly rapid recovery of camels when water is available again.

Methane emission by alpaca and sheep fed on lucerne hay or grazed on pastures of perennial ryegrass/white clover or birdsfoot trefoil

Based on the knowledge that alpaca (Lama pacos) have a lower fractional outflow rate of feed particles (particulate FOR) from their forestomach than sheep (San Martin 1987), the current study measured methane (CH4) production and other digestion parameters in these species in three successive experiments (1, 2 and 3): Experiment 1, lucerne hay fed indoors; Experiment 2, grazed on perennial ryegrass/white clover pasture (PRG/WC); and Experiment 3, grazed on birdsfoot trefoil (Lotus corniculatus) pasture (Lotus). Six male alpaca and six castrated Romney sheep were simultaneously and successively fed on the forages either ad libitum or at generous herbage allowances (grazing). CH4 production (g/day) (using the sulphur hexafluoride tracer technique), voluntary feed intake (VFI), diet quality, and protozoa counts and volatile fatty acid concentrations in samples of forestomach contents were determined. In addition, feed digestibility, energy and nitrogen (N) balances and microbial N supply from the forestomach (using purine derivatives excretion) were measured in Experiment 1.Diets selected by alpaca were of lower quality than those selected by sheep, and the voluntary gross energy intakes (GEI, MJ) per kg of liveweight0·75 were consistently lower (P&lt;0·001) for the alpaca than for the sheep (0·74 v. 1·36, 0·61 v. 1·32 and 0·77 v. 2·53 on lucerne hay, PRG/WC and Lotus, respectively). Alpaca and sheep did not differ (P&gt;0·05) in their CH4 yields (% GEI) when fed on lucerne hay (5·1 v. 4·7), but alpaca had a higher CH4 yield when fed on PRG/WC (9·4 v. 7·5, P&lt;0·05) and Lotus (6·4 v. 2·7, P&lt;0·001). When grazing on Lotus, the sheep had very high protozoa counts in their forestomach contents, compared with those with the other forages and those in the alpaca. On lucerne hay and Lotus, but not on PRG/WC, the alpaca had higher (P&lt;0·01) acetate/propionate ratio in their forestomach fluid than sheep. When fed on lucerne hay, alpaca and sheep did not differ (P&gt;0·05) in diet N partition or microbial N yield, but alpaca had higher (P&lt;0·05) neutral detergent fibre digestibility (0·478 v. 0·461) and lower (P&lt;0·01) urinary energy losses (5·2 v. 5·8 % GEI) than sheep. It is suggested that differences between these species in forestomach particulate FOR might have been the underlying physiological mechanism responsible for the differences in CH4 yield, although the between-species differences in VFI and diet quality also had a major effect on it.

Chitinolytic bacteria in the minke whale forestomach.

Minke whales consume large amounts of pelagic crustaceans. Digestion of the prey is initiated by indigenous bacteria in a rumen-like forestomach system. A major structural component of the crustacean exoskeleton is chitin, the beta-1,4-linked polymer of N-acetyl-D-glucosamine. The exoskeletons appear to dissolve completely in the non-glandular forestomach. Bacteria in the forestomach fluid of six krill-eating minke whales were enumerated and isolated using an anaerobic habitat-simulating culture medium. Median viable population densities ranged between 6.0 x 10(6) and 9.9 x 10(9) bacterial cells per mL forestomach fluid. Bacterial isolates (n = 44) cultured from the forestomach fluid of one minke whale mainly resembled strains of Eubacterium (25%), Streptococcus (18%), Clostridium (14%), and Bacteroides (11%). As much as 12% of the bacterial isolates were chitinolytic, while beta-N-acetylglucosaminidase activity was demonstrated in 54% of the isolates, and utilisation of N-acetyl-D-glucosamine was observed in 73%. The chitinolytic isolates resembled strains of Bacteroides, Bacteroidaceae, Clostridium, and Streptococcus. Scanning and transmission electron microscopy of partly digested krill from the minke whale forestomach revealed bacteria close to and inside the chitinous exoskeleton. The bacterial chitinase may act on the chitinous crustacean exoskeletons, thereby allowing other bacteria access to the nutritious soft inner tissues of the prey, and thus initiating its degradation and fermentation.

Chitinolytic bacteria in the minke whale forestomach

Minke whales consume large amounts of pelagic crustaceans. Digestion of the prey is initiated by indigenous bacteria in a rumen-like forestomach system. A major structural component of the crustacean exoskeleton is chitin, the β-1,4-linked polymer of N-acetyl-D-glucosamine. The exoskeletons appear to dissolve completely in the non-glandular forestomach. Bacteria in the forestomach fluid of six krill-eating minke whales were enumerated and isolated using an anaerobic habitat-simulating culture medium. Median viable population densities ranged between 6.0 × 106and 9.9 × 109bacterial cells per mL forestomach fluid. Bacterial isolates (n = 44) cultured from the forestomach fluid of one minke whale mainly resembled strains of Eubacterium (25%),Streptococcus (18%), Clostridium (14%), and Bacteroides (11%). As much as 12% of the bacterial isolates were chitinolytic, while β-N-acetylglucosaminidase activity was demonstrated in 54% of the isolates, and utilisation of N-acetyl-D-glucosamine was observed in 73%. The chitinolytic isolates resembled strains of Bacteroides, Bacteroidaceae, Clostridium, and Streptococcus. Scanning and transmission electron microscopy of partly digested krill from the minke whale forestomach revealed bacteria close to and inside the chitinous exoskeleton. The bacterial chitinase may act on the chitinous crustacean exoskeletons, thereby allowing other bacteria access to the nutritious soft inner tissues of the prey, and thus initiating its degradation and fermentation.Key words: chitinase, β-N-acetylglucosaminidase, cetacea, symbiotic microbial digestion.

Na transport in sheep rumen is modulated by voltage-dependent cation conductance in apical membrane.

The effects of clamping the transepithelial potential difference (PDt; mucosa reference) have been studied in sheep rumen epithelium. Pieces of ruminal epithelium were examined in Ussing chambers, in a part of the experiments combined with conventional intracellular recordings. After equilibration, the tissue conductance (Gt) was 2.50 +/- 0.09 mS/cm(2), the potential difference of the apical membrane (PD(a)) was -47 +/- 2 mV, and the fractional resistance of the apical membrane (fRa) was 68 +/- 2% under short-circuit conditions. Hyperpolarization of the tissue (bloodside positive) depolarized PDa, decreased fRa, and increased Gt significantly. Clamping PDt at negative values caused converse effects on PDa and fRa. All changes were completely reversible. The determination of individual conductances revealed that the conductance of the apical membrane increased almost linearly with depolarization of PDa. The PD-dependent changes were significantly reduced by total replacement of Na. These observations support the assumption of a PD-dependent conductance in the apical membrane that permits enhanced apical uptake of Na even at depolarized PDa. This mechanism appears to be important for the regulation of osmotic pressure in forestomach fluid.

Ciliate protozoa in the forestomach of the dromedary camel, (Camelus dromedarius), in Egypt, with description of a new species.

The composition of ciliates obtained from the forestomachs of eleven dromedary (one-humped) camels in Egypt was examined. As a result, eight genera containing 24 species with 11 forms were identified. Of them, one species was concluded to be new, then described as Dasytricha kabanii n. sp. This new species was clearly distinguished from D. ruminantium, the other species of the genus, by its lack of somatic cilia on the posterior one-fifth of the body surface. Entodinium nanellum and Epidinium ecaudatum f. caudatum were found in all camels examined. Although the percentage composition of respective species varied with the individual camel, the rate of Entodinium spp. was high in general. Total ciliate density in forestomach fluid was 1.9 x 10(5)/ml on average. Ciliate composition in Egyptian camels was similar to that in Bactrian camels, Camelus bactrianus, in China reported previously. However, more Entodinium species were detected from Egyptian camels than from Bactrian camels.

Chitinolytic bacteria in the minke whale forestomach

Minke whales consume large amounts of pelagic crustaceans. Digestion of the prey is initiated by indigenous bacteria in a rumen-like forestomach system. A major structural component of the crustacean exoskeleton is chitin, the β-1,4-linked polymer of N-acetyl-D-glucosamine. The exoskeletons appear to dissolve completely in the non-glandular forestomach. Bacteria in the forestomach fluid of six krill-eating minke whales were enumerated and isolated using an anaerobic habitat-simulating culture medium. Median viable population densities ranged between 6.0 × 10 6 and 9.9 × 10 9 bacterial cells per mL forestomach fluid. Bacterial isolates ( n = 44) cultured from the forestomach fluid of one minke whale mainly resembled strains of Eubacterium (25%), Streptococcus (18%), Clostridium (14%), and Bacteroides (11%). As much as 12% of the bacterial isolates were chitinolytic, while β-N-acetylglucosaminidase activ- ity was demonstrated in 54% of the isolates, and utilisation of N-acetyl-D-glucosamine was observed in 73%. The chitinolytic isolates resembled strains of Bacteroides, Bacteroidaceae, Clostridium, and Streptococcus. Scanning and transmission electron microscopy of partly digested krill from the minke whale forestomach revealed bacteria close to and inside the chitinous exoskeleton. The bacterial chitinase may act on the chitinous crustacean exoskeletons, thereby allowing other bacteria access to the nutritious soft inner tissues of the prey, and thus initiating its degradation and fer - mentation.

Production rates of volatile fatty acids in the minke whale (Balaenoptera acutorostrata) forestomach.

Minke whales (Balaenoptera acutorostrata) have developed a compartmentalized stomach system, which includes a non-glandular forestomach containing high concentrations of indigenous bacteria. The forestomach contents serve as microbial substrate, and samples were collected from five adult minke whales eating capelin (Mallotus villosus) and crustaceans (Thysanoessa sp.). Chemical analysis of the forestomach contents revealed that they consisted of crude protein (650 (SD 58) g/kg DM), lipid (330 (SD 77) g/kg DM) and water-soluble carbohydrates (53.3 (SD 7.3) g/kg DM). The contribution of energy from volatile fatty acids (VFA), produced by forestomach bacterial fermentation, to the total energy budget was estimated. The forestomach concentration of VFA ranged from 13.2 to 68.5 mmol/l, and the pH was 5.83 (SD 0.41). VFA pool size ranged from 72.8 to 638.1 mmol and represented from 0.169 to 2.107 kJ/kg live weight (W)0-75. Maximal recorded forestomach VFA production rate was 1694 mmol/h in one capelin-eating minke whale with 42.6 litres of forestomach fluid. Energy from VFA produced by forestomach fermentation represented 6-107 kJ/kg (W)0-75 per d, which accounts for only 0.9-16.9% of the average daily energy expenditure of minke whales. This study suggests that the bacterial fermentation in the minke whale forestomach varies, depending on the volume and the quality of substrate available, influencing fermentation rates and concentration of VFA. Due to the small relative size of the forestomach, the contribution of VFA to the daily energy requirement in minke whales would be of less importance than in ruminants even when assuming the same production rate of VFA as in a ruminant.

Digestion of Herring by Indigenous Bacteria in the Minke Whale Forestomach

Northeastern Atlantic minke whales (Balaenoptera acutorostrata) have a multichambered stomach system which includes a nonglandular forestomach resembling that of ruminants. Bacteria from the forestomachs of herring-eating whales were enumerated and isolated in an anaerobic rumen-like culture medium (M8W medium). The total viable population of anaerobic bacteria ranged from 73 x 10 to 145 x 10/ml of forestomach fluid (n = 4). Lactobacillus spp. (19.7%), Streptococcus spp. (35.9%), and Ruminococcus spp. (12.8%) were the most common of the bacterial strains (n = 117) isolated by use of M8W medium from the forestomach fluid population of two minke whales. Most of the isolates stained gram positive (93.2%), 62.4% were cocci, and all strains were strictly anaerobic. The population of lipolytic bacteria in one animal, enumerated by use of a selective lipid medium, constituted 89.7% of the viable population. The total viable population of anaerobic bacteria in freshly caught and homogenized herring (Clupea harengus) ranged from 56.7 to 95.0 cells per gram of homogenized prey (n = 3) when M8W medium was used. Pediococcus spp. (30.6%) and Aerococcus spp. (25.0%) were most common of the bacterial strains (n = 72) isolated from the homogenized herring. Most of the bacterial strains were gram positive (80.6%), and 70.8% were cocci. Unlike the forestomach bacterial population, as many as 61.1% of the strains from the herring were facultatively anaerobic. All bacterial strains isolated from the prey had phenotypic patterns different from those of strains isolated from the dominant bacterial population in the forestomach, indicating that the forestomach microbiota is indigenous. Scanning electron microscopic examinations revealed large numbers of bacteria, surrounded by a glycocalyx, attached to partly digested food particles in the forestomach. These data support the hypothesis that symbiotic microbial digestion occurs in the forestomach and that the bacteria are indigenous to minke whales.

Probe for collection of ruminal fluid in juvenile cattle and cows

In order to avoid saliva contamination, forestomach fluid used for diagnostic purposes should be collected from the ventral sac of the rumen. For adult cattle, instruments are commercially available. In juvenile cattle there are no instruments available that are tested for these purposes. Tolgyesi and Goots used Kaltenbock's probe to collect ruminal fluid in adult cattle. This instrument was developed for the treatment of foamy bloat. It is obtainable in two different sizes for use in adult and juvenile cattle. We modified the model for juvenile cattle and tested it in juvenile cattle and cows for the collection of ruminal fluid.

Seasonal changes of ingesta mean retention time and forestomach fluid volume in indigenous camels, cattle, sheep and goats grazing a thornbush savannah pasture in Kenya

SUMMARYThe study was carried out in northern Kenya in 1984–87. Forestomach volumes and digesta retention times were measured using Cr-EDTA or Co-EDTA as fluid markers and Ce-labelled particles or Cr-mordanted particles as paniculate phase markers.Mean retention times of fluid and of particles were longer in the dry season than in the green season in all four animal species. The increase of particle mean retention time, as a percentage of the values in the green season, was highest in sheep (46%), followed by cattle (27%), goats (22%) and camels(18%). Forestomach volumes were also greater in the dry than in the green season; the increase was again highest in sheep (55%), followed by cattle (31%), goats (29%) and camels (28%). Outflow rates of fluid from the forestomach and the selectivity factor, by which small particles were retained longer in the forestomach than fluid, did not differ significantly between the seasons.It is suggested that the increase of forestomach volumes is an effective adaptation to dry-season pasture conditions. It enables the animals to retain feed particles longer in the forestomach and so improve fibre digestion when feed quality is low. Cattle and sheep, which depend on a poor quality diet, improve fibre digestion in this way in the dry season more effectively than camels and goats. Camels and goats, on the other hand, were able to select a diet of such quality, even in the dry season, that their need to augment fibre digestion was reduced.

Forestomach fluid volume and retention of fluid and particles in the gastrointestinal tract of the camel (Camelus dromedarius).

SummaryThe mean retention time of fluid in the forestomach of the camel is significantly shorter than of particles, 13.9 versus 48.8 hours. Particles of 2–3 cm have slightly longer retention times than particles of 1–2 mm. In the intestine retention times of fluid, large and small particles are similar (30.9–37.7 hours). The forestomach volume of the camel depends on the water content of the feed.ZusammenfassungDie Retentionszeit der Flüssigkeit (13,9 Std.) in den Vormägen der Kamele ist signifikant kürzer als die der Partikel. Die mittlere Verweilzeit von Partikeln betrug 48,8 Stunden. 2–3 cm lange Partikel haben längere Verweilzeiten als 1–2 mm lange. Die Passagezeiten durch den Darm sind etwa gleich lang für Flüssigkeit, für kleine und für große Partikel (30,9–37,7 Std.). Das Vormagenvolumen der Kamele hängt vom Wassergehalt des Futters ab.