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At least 19 recordsLinked to original sources

PubMed2025

Altered ruminal microbiome tryptophan metabolism and their derived 3-indoleacetic acid inhibit ruminal inflammation in subacute ruminal acidosis goats.

BACKGROUND: Subacute ruminal acidosis (SARA) is a digestive disorder that often severely jeopardizes the health and lactation performance of ruminants fed a high-energy diet. Different dairy ruminants exhibit varying degrees of inflammation accompanied by variations in the rumen microbiota when SARA occurs. Our understanding of the occurrence of SARA and varying degrees of rumen epithelial inflammation is lacking. Hence, we performed rumen metagenomic, metagenome-assembled genome and metabolomic analyses, with transcriptome and single-nucleus RNA sequence analyses, to explore the microbial mechanism of SARA occurrence and different degrees of inflammation. RESULTS: A total of 36 goats fed two diets with gradually increasing levels of rumen-degradable starch (RDS) were included in this study, and SARA goats fed 70% concentrate diets supplemented with whole corn (HGW-SARA) and SARA goats fed 70% concentrate diets supplemented with crushed corn (HGC-SARA) were identified. Moreover, 11 goats fed a control basal diet, named LGW-CON, were also included. Compared with those in the LGW-CON group, the rumen fermentation capacity was enhanced, accompanied by ruminal epithelial and systemic inflammation, in goats from HGW-SARA and HGC-SARA. Between them, HGC-SARA goats presented less inflammation. Notably, the ruminal inflammation-related pathways were increased only in the HGW-SARA group but not in the HGC-SARA group. Metagenomic analysis revealed that the β diversity of SARA goats was significantly different from that of LGW-CON goats. Ruminococcus significantly increased in both SARA groups, whereas Prevotella and Bacteroidales significantly decreased, which was accompanied by a decrease in cellulose and hemicellulose enzymes and an increase in lysozymes and lipopolysaccharide synthesis enzymes. Multi-omics analysis of the ruminal contents and tissues suggested that epithelial inflammation was caused by disturbed ruminal microbiome-induced Th17 cell differentiation and IL-17 signalling pathway activation. Comparative analyses between the HGW-SARA and HGC-SARA groups highlighted the importance of Selenomonas and Bifidobacterium, as well as bacterial tryptophan metabolism, in the production of 3-indoleacetic acid, which mitigated ruminal epithelial inflammation by modulating Th17 cells and inhibiting IL-17 signalling. Ruminal microbiota transplantation from HGW-SARA goats to healthy dairy goats and mice revealed the role of microbes in epithelial inflammation. Additionally, 3-indoleacetic acid supplementation reduced rumen inflammation and the IL-17 concentration in the serum, improved VFAs absorption, and enhanced milk production. CONCLUSIONS: This study unveiled that after SARA was induced by high-concentrate feeding, the rumen homeostasis was disrupted, and rumen fiber degradation capacity of dairy goats decreased, but the LPS synthesis capacity increased, and inflammation of the rumen epithelium was observed. However, the ruminal microbial species from the Bifidobacterium and Selenomonas genera and bacterial 3-indole acetic acid are pivotal in mitigating ruminal epithelial inflammation during SARA in dairy goats. This could potentially be attributed to the modulation of ruminal Th17 cell proportions and the inhibition of IL-17 signalling pathways. Video Abstract.

Rumen↗

PubMed2006

On the measurement of rumination: a psychometric evaluation of the ruminative response scale and the rumination on sadness scale in undergraduates.

Rumination is considered a specific cognitive vulnerability factor that is thought to play a prominent role in the maintenance of depressive symptoms. The present study investigated the psychometric properties of two measures of rumination, the ruminative response scale (RRS) and the rumination on sadness scale (RSS) in undergraduates (N=331). A joint factor analysis yielded three factors, 'rumination on causes of sadness', 'symptom-based rumination', and 'rumination on sadness'. The internal consistency of the rumination factors was good and the test-retest stability over a 6-month period of time was moderate. Support was also found for the construct validity of the rumination factors. Finally, the 'rumination on the causes of sadness' factor was found to moderate the relation between depression measured at baseline and at 6-month follow-up. More specifically, baseline depression was a strong predictor of future depression but this was particularly true for high ruminating individuals. Implications of the results and directions for future research are provided.

Adolescent↗

PubMed1990

Ruminal fermentation pattern, bacterial population and ruminal degradation of feed ingredients as influenced by ruminal ammonia concentration.

The effects of ruminal ammonia concentration on bacterial numbers, fermentation pattern and degradation of feed ingredients in the rumen were examined with three nonlactating Holstein cows fitted with ruminal cannulas. Cows were fed twice daily a complete mixed diet (90% whole plant oat silage and 10% concentrate mixture) containing 11.1% CP on a DM basis. Ammonium bicarbonate (NH4HCO3) was infused continuously into the rumen at levels of 0, 95, 190 or 280 g/d. Infusion of NH4HCO3 linearly increased (P less than .05) the concentrations of ruminal ammonia and blood urea N. Total VFA concentrations and mixed bacterial numbers also were increased (P less than .05) by NH4HCO3 infusion. Infusions of NH4HCO3 increased (P less than .05) butyrate and decreased (P less than .05) isobutyrate and isovalerate proportions. Infusion of NH4HCO3 increased (P less than .05) rate of degradation of soybean meal DM but did not (P greater than .05) influence degradation characteristics of fish meal and barley grain. In conclusion, supplementation of N by continuous infusion of NH4HCO3 appeared to stimulate bacterial growth and fermentation but it did not influence extent of ruminal degradation of selected feed ingredients.

Ammonia↗

PubMed1976

Relationship between ruminal ammonia and nonprotein nitrogen utilization by ruminants. III. Influence of intraruminal urea infusion on ruminal ammonia concentration.

In three trials, we studied the effect of incremental amounts of intraruminally infused urea on mean ruminal ammonia concentration of steer fed at 2-h intervals. Basal rations contained these percentages of crude protein and total digestible nutrients (dry matter basis); Trial I, 11.1 and 81; Trial II, 6.0 and 54; Trial III, 6.5 and 58. Mean ruminal ammonia concentration reached 5 mg ammonia nitrogen/100 ml rumen fluid at crude protein equivalents of 12.0, 9.3, and 9.4% in I, II, and III. Once ruminal ammonia began to accumulate, there was a linear relationship between intake of urea and mean concentration of amino acids of plasma, serving as an indirect measure of amino acid absorption from the intestine, was not increased by increased intake of urea in III. Results of this experiment support the concept from in vitro data that microbial protein synthesis is unaffected by ruminal ammonia concentration in excess of 5 mg ammonia nitrogen/100 ml rumen fluid.

Amino Acids↗

PubMed1991

Effects of animal-to-animal exchange of ruminal contents on the feed intake and ruminal characteristics of fed and fasted lambs.

Four Suffolk x Hampshire wether lambs averaging 55 kg with permanent ruminal cannulas were used in a 4 x 4 Latin square design to determine the effects of exchange of ruminal contents between fed and fasted lambs on subsequent DMI and ruminal characteristics. Lambs were fed a pelleted 70% roughage diet at 2% of BW for 17 d. During each period of the Latin square two lambs were deprived of feed and water for 3 d. At the end of the fasting period ruminal contents from one fed and one fasted lamb were exchanged. Lambs were then given ad libitum access to feed for 8 d, during which DMI, feeding pattern, and ruminal characteristics were monitored. Measurements of ruminal volume determined by total collection and indigestible marker (lithium sulfate) suggested that only about 50% of total ruminal contents were actually exchanged. Fasted lambs had lower (P less than .05) DMI, ruminal fermentative capacity, ruminal DM weight, and ruminal DM percentage than fed lambs during the first 4 d of realimentation. Exchange of ruminal contents did not (P greater than .10) affect DMI, feeding pattern, ruminal fluid pH, ruminal fermentative capacity, ruminal contents DM percentage, ruminal nucleic acid concentration, or VFA. Dosing fasted lambs with ruminal contents from nonfasted lambs reduced (P less than .05) ruminal liquid volume, dry weight of ruminal contents, and propionate concentration. Results of this trial are interpreted to indicate that although decreased ruminal function is a factor in the low feed intakes of fasted ruminants, the possibility of increasing postfast feed intake via improved ruminal function is limited because other metabolic factors may play a more important role.

Animals↗

PubMed1987

Interrelationships among voluntary intake, eating and ruminating behavior and ruminal motility of heifers fed corn silage.

Six heifers (1/4 Brahman X 1/4 Jersey X 1/2 Angus, 290 kg average weight) with ruminal, duodenal and ileal cannulae given ad libitum access to corn silage with or without 100 mg monensin X head-1 were used to determine interrelationships among behavior, ruminal motility and intake. Voluntary intake was positively related (P less than .001) to eating time, duration of the main morning meal and daily mastication time. Intake was negatively related to unitary times [min X g dry matter-1 X (kg body weight X 75)-1] of eating (P less than .05), rumination (P less than .001), mastication (P less than .001), unitary number of rumination boli (P less than .001), and latency time between termination of morning meal and onset of rumination (P less than .05). Both daily and unitary eating and ruminating time were positively related (P less than .001) to daily and unitary mastication time and unitary number of strong cranio-dorsal ruminal contractions. Positive relationships (P less than .01) were found between mean duration of daily meals, main evening meal and unitary eating time, and between mean duration of rumination periods and unitary ruminating time. Daily and unitary number of rumination boli and mean duration of one bolus were positively related (P less than .01) to unitary ruminating time. Interrelationships between intake, eating and ruminating activities and associated cranio-dorsal ruminal motility were all influenced (P less than .01) by individual heifer, which indicates potential in identifying individuals with better than average mastication behavior and ruminal motility.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1998

Biochemical and ribotypic comparison of Actinomyces pyogenes and A pyogenes-like organisms from liver abscesses, ruminal wall, and ruminal contents of cattle.

OBJECTIVE: To isolate Actinomyces pyogenes and A pyogenes-like (APL) organisms from the ruminal wall and ruminal contents of cattle and compare them with isolates from liver abscesses from the same animals, using ribosomal DNA restriction fragment length polymorphism analysis or ribotyping. PROCEDURE: Specimens of liver abscesses, ruminal walls, and ruminal contents were collected from 59 cattle at slaughter. All beta-hemolytic, pinpoint colonies that were gram positive, pleomorphic rod-shaped, and catalase negative, and that hydrolyzed casein and gelatin were presumptively identified as A pyogenes and were characterized biochemically, using an identification kit. The isolates that resembled A pyogenes but fermented mannitol or raffinose, or both, were called APL organisms. Isolates from the ruminal wall and ruminal contents were compared with liver abscess isolates from the same animal by use of ribotyping. RESULTS: Actinomyces pyogenes and APL organisms were isolated more frequently from the ruminal wall than from ruminal contents. Ruminal isolates of A pyogenes and APL had biochemical characteristics similar to those of the isolates from liver abscesses. Among 6 sets of isolates (4 A pyogenes and 2 APL), 2 isolates from liver abscesses had ribopatterns identical to the corresponding ruminal wall isolates. Also, the APL organisms isolated from the ruminal content matched with the corresponding liver abscess isolates for both sets of specimens tested. CONCLUSIONS: The ruminal wall may be the niche for A pyogenes and APL organisms in the rumen. The genetic similarity, on the basis of ribotyping among isolates from liver abscesses, the ruminal wall, and ruminal contents of the same animal suggests that A pyogenes and APL organisms that cause liver abscesses originate from the rumen.

Abscess↗

PubMed1994

Ruminal microbiology, biotechnology, and ruminant nutrition: progress and problems.

Present methods for manipulating ruminal fermentation that involve microbial biotechnology include dietary ionophores, antibiotics, and microbial feed additives. Developments in recombinant DNA technology mean that future methods will have a much wider scope. It has been suggested that genetically engineered ruminal microorganisms will be used in future to improve ruminal fermentation. Several technical objectives must be achieved before that will be possible. First, methods for inserting foreign or modified genes into ruminal microorganisms and ensuring their efficient expression must be developed. Broad host range plasmids and transposons have been used successfully to introduce new DNA into ruminal bacteria, as have shuttle vectors constructed as chimeras of plasmids from ruminal species and Escherichia coli. Although so far only antibiotic resistance markers have been transferred, the prospects for introducing other genes into selected ruminal bacteria are excellent. Second, the expression of the gene product(s) should be known to be nutritionally useful in vivo. A few examples of this type of benefit have been demonstrated, and many more proposed, including polysaccharidases for improving fiber digestion, methods for improving the amino acid composition of ruminal bacteria, and breakdown of plant toxins. Third, the difficulty that has been examined least, yet may prove most difficult to overcome, is that mechanisms have to be found for introducing and maintaining the new strain in the mixed ruminal population. Factors governing the survival of new strains in vivo are ill-understood, and attempts to select in favor of added new organisms have so far been unsuccessful. Because of the last obstacle, it may be advantageous, at least in the short term, to use nonruminal organisms, such as Saccharomyces cerevisiae, rather than indigenous ruminal species as a vehicle for implementing the benefits of recombinant DNA technology to ruminal fermentation. Yeast is already in widespread use as a feed additive, so no enrichment is necessary; and its genetics are already well known. Alternatively, adding particular enzymes to the diet may achieve some of the objectives described above, with the advantage that the manipulation could be achieved without the release of a recombinant microorganism.

Animal Nutritional Physiological Phenomena↗

PubMedDate not supplied

Effects of intake level of a mixed diet on chewing activity and on particle size of ruminated boli, ruminal digesta fractions and faeces of steers.

This study evaluated the effects of intake of a mixed diet on chewing activity during eating and rumination and the relationship between the chewing activity and the particle size of the ruminated boli, ruminal digesta fractions and faeces in steers. Six ruminally cannulated steers received a mixed forage/concentrate diet (68:32, dry matter basis). The diet was offered twice daily at approximately 1, 1.5 and 2 times the estimated maintenance energy requirements (low, medium and high intake, respectively) in a repeated 3 x 3 Latin square design. The rumens were emptied manually and samples of the ruminated boli and of the ruminal upper strata were collected at four different times throughout the day. The dry matter weight distribution of the total amount of recovered particles was determined by a wet-sieving procedure. Numerically, the effect of intake on the mean particle sizes of the different materials was small. However, the mean particle size was reduced by almost nine tenths from their size at intake of the mixed diet (4.78 mm) to defecation (0.51 mm). The total number of minutes chewing and eating and ruminating increased as the intake level increased. When related to 1 kg of dry matter intake, only the eating and chewing times were significantly longer for the high as compared to the medium intake. Rumination patterns were examined using a cosinor model. Data indicated that the average amount of time spent ruminating also increased as the intake level increased. The overall pattern of rumination was not impaired by higher intake levels. The amount of large (> or = 4 mm) particles that escaped per minute of rumination time between 3 and 7.5 h postfeeding was similar for all the intake levels. It was concluded that an active breakdown process occurred in the rumen which could cope with the higher intake levels of the mixed diet over the range of 1 to 2 times the maintenance energy requirement level.

Animal Feed↗

PubMed1987

Effects of monensin on voluntary intake, eating and ruminating behavior and ruminal motility in heifers fed corn silage.

Eating and ruminating behavior and associated ruminal motility of six heifers (1/4 Brahman X 1/4 Jersey X 1/2 Angus, 290 kg average weight) given ad libitum access to corn silage with or without 100 mg monensin X head-1 X d-1 were examined according to a two-period crossover design. There was no effect (P greater than .05) of monensin on level of intake, daily and unitary eating, ruminating and masticating times [min X g dry matter-1 X (kg body weight X 75)-1], duration or number of these activity periods, duration of main meals or latency time for onset of rumination following cessation of main eating activities. With the monensin treatment, daily numbers of normal boli and total boli were decreased (P less than .05) and mean duration of one rumination bolus cycle was longer (P less than .05). Analysis of covariance indicated relationships between intake of corn silage and duration of the main morning meal, duration or number of rumination boli and total ruminal contractions were affected (P less than .01) by monensin. Frequency and unitary number of strong cranio-dorsal ruminal contractions were similar for both treatments. During eating, number of contractions per minute was about twice (2.55/min) that during idling and rumination activity (1.43/min and 1.22/min, respectively). The unitary daily number of contractions was negatively (P less than .05) related to level of intake. Total daily ruminal contractions were slightly reduced (-3.96%, P greater than .05) by monensin. Results are interpreted to suggest that monensin indirectly affects rumination through a lowered motility and thereby affects turnover, gut fill and intake.

Animals↗

PubMed2004

Effect of sodium laurate on ruminal fermentation and utilization of ruminal ammonia nitrogen for milk protein synthesis in dairy cows.

A crossover design trial with 4 ruminally and duodenally cannulated lactating dairy cows was conducted to study the effect of sodium laurate on ruminal fermentation, nutrient digestibility, and milk yield and composition. The daily dose of sodium laurate (0, control or 240 g/cow, LA) was divided in 2 equal portions and introduced directly into the rumen through the cannula before feedings. Ruminal samples (29 in 114 h) were analyzed for fermentation variables and protozoal counts. Sodium laurate had no effect on ruminal pH and total and individual volatile fatty acids concentrations. Ruminal ammonia concentration, ammonia N pool size, and the irreversible loss of ammonia N were unaffected by treatment. Compared to control, protozoal counts were reduced by 91% by LA. Carboxymethylcellulase and xylanase activities of ruminal fluid were decreased (by 40 and 36%, respectively), and amylase activity was not affected by LA compared with control. Flow of microbial N to the duodenum was reduced by LA. Dry matter intake and apparent total tract digestibility of dry matter, organic matter, crude protein, neutral detergent fiber, and acid detergent fiber were not different between the 2 treatments. Milk yield, fat-corrected milk yield, milk fat and protein concentrations and yields, and milk urea N content were not affected by treatment. Sodium laurate did not affect transfer of ruminal ammonia-15N into bacterial or milk protein. In conclusion, LA at approximately 0.3% of the rumen weight reduced ruminal protozoal population and had a negative effect on fibrolytic activities of ruminal fluid and microbial protein flow to the intestine. Treatment had no other significant effects on ruminal fermentation, total tract digestibility, or transfer of ruminal ammonia-15N into milk protein.

Ammonia↗

PubMed2005

Breathing frequency in ruminants: a comparative analysis with non-ruminant mammals.

In cattle, sheep and goats, during resting conditions, breathing frequency (f) greatly exceeds the value expected for their body weight (W, kg) from the allometric curve of other land mammals. It was postulated that this was the effect of the production of CO2 during rumen fermentation. If this were the case, a high f should be a general characteristic of ruminants. Measurements of f have been obtained in 106 awake and resting animals of 56 species, of which 30 were non-ruminant land mammals, and 26 were ruminants. The ruminant species comprised 15 Bovidae (B), 6 Cervidae (CR), 3 Camelidae (CM), and 2 Giraffidae (G). Additional data of 14 species were available from the literature. The allometric function (f, breaths/min; W, kg) for non-ruminant species was f=53W(-0.251) and not different between males and females. The allometric curve remained unaltered with the inclusion of the 11 species of CR, CM and G, but it was greatly modified by the B species. The significantly higher f in ruminants, as a group, was contributed by B (P<0.001), whereas the f of CR, CM and G did not differ significantly from the non-ruminant values. We conclude that the high f of cattle and other domestic ruminants is a characteristic shared by many other species of the Bovidae family, but is not a general feature of ruminants. Out of various possibilities, it seems most probable that the tachypnea of Bovidae is in response to the elastic load imposed on the respiratory system by the rumen, the size of which exceeds that of other families of ruminants.

Animals↗

PubMed1997

Ribotyping to compare Fusobacterium necrophorum isolates from bovine liver abscesses, ruminal walls, and ruminal contents.

Restriction fragment length polymorphism analysis of rRNA genes was employed to genetically compare Fusobacterium necrophorum subsp. necrophorum and F. necrophorum subsp. funduliforme isolates from multiple abscesses of the same liver and isolates from liver abscesses, the ruminal wall, and ruminal contents from the same animal. Four livers with multiple abscesses and samples of ruminal contents, ruminal walls, and liver abscesses were collected from 11 cattle at slaughter. F. necrophorum was isolated from all liver abscesses, nine ruminal walls, and six ruminal content samples. Chromosomal DNA of the isolates was extracted and single or double digested with restriction endonucleases (EcoRI, EcoRV, SalI, and HaeIII); then restriction fragments were hybridized with a digoxigenin-labeled cDNA probe transcribed from a mixture of 16S and 23S rRNAs from Escherichia coli. EcoRI alone or in combination with EcoRV yielded the most discriminating ribopatterns for comparison. Within the subspecies multiple isolates from the same liver were indistinguishable based on the ribopattern obtained with EcoRI. The hybridization patterns of liver abscess isolates were concordant with those of the corresponding isolates from ruminal walls in eight of nine sets of samples. None of the six ruminal content isolates matched either the liver abscess isolates or the ruminal wall isolates. The genetic similarity between the isolates from liver abscesses and ruminal walls supports the hypothesis that F. necrophorum isolates of liver abscesses originate from the rumen.

Animal Feed↗

PubMed1989

Effects of a monensin ruminal delivery device on daily gain, forage intake and ruminal fermentation of steers grazing irrigated winter wheat pasture.

Two trials evaluated the effects of a monensin ruminal delivery device (MRDD) on steers grazing winter wheat pasture. In Trial 1, 60 Hereford steers (initial wt 238.5 kg) grazed a 21.9-ha paddock of Vona-variety winter wheat for 112 d. Steers were assigned to either MRDD or control (C) treatments in a randomized complete block design. In Trial 2, eight ruminally cannulated steers (avg wt 234.4 kg) grazed a 2.4-ha paddock of Vona-variety wheat and were assigned randomly to either MRDD or C treatments. Three 11-d collection periods were conducted during early February, early March and early April. Chromic oxide was dosed to determine fecal output, and ruminal samples were collected on d 6 of each period. Nylon bags containing ground wheat forage were incubated ruminally beginning on d 8. In Trial 1, steers with MRDD tended (P less than .11) to gain more weight than C steers (.44 vs .38 kg/d). In Trial 2, wheat forage intake, in situ DM disappearance, ruminal pH, ruminal ammonia concentrations and ruminal proportions of acetate and total VFA concentrations were not affected by treatment. Ruminal proportions of propionate were increased (P less than .05) slightly by MRDD (20.3 and 19.2 mol/100 mol for MRDD and C, respectively). Butyrate proportions in ruminal samples were decreased (P less than .05) by MRDD during March but not in other sampling periods. Ruminal fluid chlorophyll concentration was less (P less than .05) for MRDD-treated vs C steers during early March but was greater (P less than .10) for MRDD-treated steers during early April. The MRDD shows promise as a method of supplying monensin to cattle grazing winter wheat forage.

Animal Feed↗

PubMed1984

[Feeding behavior, rumination, reticulo-ruminal fermentation and plasma volatile fatty acids, compared in goats and sheep; influence of the diet].

Two-year old Alpine she-goats (n = 3) and Texel ewes (n = 3) were compared as to eating behaviour, rumination and volatile fatty acids (VFA) in rumen and blood. The animals were fed once daily with two different proportions (20 and 80%) of barley and hay. Dry matter intake was fixed at 48 g D.M/kg P0.75 per day. In similar feeding and environmental conditions, eating behaviour and rumination of goats and sheep did not differ much: the goats tended to eat faster and there were more rumination periods in the sheep. Latency time, mean duration of rumination periods, daily rumination time and circadian pattern of rumination did not differ significantly between the two species (fig. 1). With both diets we observed a higher VFA concentration and a lower acetate/propionate ratio in the rumen of the ewes; however, rumen pH was lower only in those eating the 80% barley ration (fig. 2). Blood VFA in the jugular vein did not differ between sheep and goats (fig. 3). The proportion of cereals and hay in the diets affected rumen fermentation and rumination pattern in both species. With a higher concentrate/roughage ratio, rumen and plasma VFA increased, while the pH and acetate/propionate ratio in the lumen juice, the number of rumination periods and daily rumination time decreased. When the animals were fed the 80% barley ration, there was practically no rumination in the first 9 h after the single meal. During this time, rumen pH was minimal and VFA levels in the rumen and blood were maximal.

Animal Feed↗

PubMed1981

Silage intake, rumination and pseudo-rumination activity in sheep studied by radiography and jaw movement recordings.

1. The eating and ruminating activity of four rams given long-chopped silage ad lib. in two daily meals was studied by jaw movement recordings. The events of rumination and pseudo-rumination were observed by fluoroscopy and by cineradiography. 2. The rate of eating was highest at the beginning of the main meal and then declined gradually. 3. The silage intake level was low. 4. The swallowed silage did not accumulate at the cardiac region but was forced into the dorsal sac of the rumen by the contractions of the reticulum and cranial sac of the rumen. For regurgitation the solid particles had to return via the ventral and cranial sac of the rumen into the reticulum. 5. Liquid reticular contents with floating solid particles were aspirated into the oesophagus during the maximum of the regurgitation contraction of the reticulum. 6. The rumination activity during the day presented a high proportion of pseudo-rumination cycles whereas during the night the rumination became progressively normal. 7. Pseudo-rumination was caused by delayed return of the fibrous silage particles into the reticulum. Thus in pseudo-rumination the regurgitated material consisted predominantly of fluid containing only a small quantity of solid particles. 8. The results explain why long-chopped silage intake is associated with pseudo-rumination, a lower breakdown of particles and a waste of digestion time.

Animal Feed↗

PubMed1995

Influence of altering ruminal degradation of soybean meal protein on in situ ruminal fiber disappearance of forages and fibrous byproducts.

The objective was to determine the effects of altering ruminal CP degradation of soybean meal (SBM) by roasting (Exp. 1) on ruminal characteristics and extents of in situ disappearance of DM, OM, and fiber components (Exp. 2). A control diet (8.2% CP) containing oat hulls, corn silage, starch grits, ammoniated corn cobs, and molasses was supplemented to 17.1% CP with unroasted SBM (SBM-0) or SBM roasted at 165 degrees C for 75, 150, or 210 min (SBM-75, SBM-150, and SBM-210, respectively). In Exp. 1, SBM was incubated for 0, 2, 4, 8, 12, 16, and 24 h in the rumen of two steers that were fed the SBM-0 diet. Extents of ruminal CP degradation and rates of N disappearance decreased (P < .05) linearly with increasing roasting time of SBM. In Exp. 2, five ruminally cannulated steers were used in a 5 x 5 Latin square design and were fed the five diets listed above during five 11-d periods. On d 11, five substrates (alfalfa hay, orchardgrass hay, corn silage, soy hulls, and wheat straw) were incubated in the rumen for 24 h. Extents of in situ disappearance of DM, OM, and fiber (NDF, ADF, cellulose, hemicellulose, and total dietary fiber) were analyzed as a split-plot design. No substrate x diet interaction (P > .05) was observed for any of the measurements evaluated. Extents of in situ disappearance (24 h) of DM, OM, and fiber were highest (P < .05) when the control diet was fed and were lowest (P < .05) when the SBM-0 diet was fed. Decreasing the availability of SBM protein in the diet by roasting increased (P < or = .10) extents of in situ disappearance of DM, OM, and fiber linearly. These extents were similar for steers fed the control diet or the diet containing SBM-210. Ruminal concentrations of NH3 N, branched-chain VFA, and valerate were highest (P < .05) and ruminal pH lowest (P < .05) when the SBM-0 diet was fed. Results indicated a rapid ruminal fermentation of both protein and readily available carbohydrates of SBM (resulting in pH below 6.0) during the first 4.5 h after feeding the SBM-0 diet. Making both protein and readily available carbohydrates of SBM more slowly fermentable by roasting slowed early fermentation processes, maintained higher ruminal pH, and encouraged earlier and faster ruminal fiber digestion.

Animal Feed↗

PubMed2000

Amino acid flux in ruminal and gastric veins of sheep: effects of ruminal and omasal injections of free amino acids and carnosine.

The possibility of free amino acid (FAA) and peptide absorption across the ruminant stomach wall was studied in multicatheterized wethers fed every 12 h. During the last third of the feeding cycle, two intraruminal or intraomasal injections of solutions containing increasing amounts of Ser, Gly, Val, Met, Phe, Lys, and carnosine were successively performed. Before injections, a net uptake of each of these FAA was measured in the ruminal and the gastric veins. The ruminal injections produced a linear increase in ruminal FAA concentration. The highest ruminal concentrations (observed with 3 g of FAA and carnosine) ranged between 5 and 14 mM. After ruminal injections, Ser (P < .05), Gly (P < .05), Val (P < .05), Met (P < .10), and Lys (P < .10) uptake decreased and carnosine net release linearly increased (P < .05), suggesting absorption across the ruminal epithelium. Owing to the low net flux generated by high ruminal concentration, the ruminal epithelium permeability to these molecules seemed to be low. After omasal injections, net flux of injected FAA were not modified, suggesting a low permeability of the gastric epithelia to FAA. Carnosine net release linearily increased (P < .05) with increasing level of carnosine injection, indicating the possibility of dipeptide absorption at the gastric level. This study demonstrated in vivo that the stomach epithelia possess the capacity to absorb FAA and small peptides; however, the permeability of these epithelia to these molecules seemed limited.

Absorption↗