Studies on the relationship of saliva to rumen function of sheep on low feed intakes
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Abstract:
Seven in vivo experiments are reported in which the effects of diverting alkaline mixed saliva from the actively fermenting contents of the rumen of anaesthetized and conscious sheep fed on a standard ration were studied for periods up to 6 hr. The absence of various quantities of saliva (225–1349 ml) was associated with profound alterations in the rumen environment: rumen liquor volatile fatty acid (V.F.A.) levels were consistently and substantially elevated, and rumen pH levels depressed. These changes in the rumen environment began about 40–60 min after saliva diversion commenced, and were sustained long after such values for the control animals had inflected towards fasting levels. Rumen movements were recorded in two experiments. Rumen movement was reduced, but not entirely suppressed, some 60 min after the minimal pH values obtained. It is suggested that this reduction in rumen movement was a consequence of depressed pH values. The rumen pH-rumen V.F.A. relationship was, in six such cases, altered but the strength of this relationship was not significantly changed. It was concluded that these effects on rumen pH-V.F.A. levels and relationship were due, directly or indirectly, to the changed buffering or osmotic regime, or both, of the saliva-depleted rumen liquor. Implications of these findings are discussed in the light of rumen physiology and the field use of oesophageally fistulated sheep.Keywords:
Volatile fatty acids
The aim of this study was to test the effect of different yeast fermented liquid on the rumen fermentation in vitro. The eight different yeast fermented liquid were added to the rumen fluid of dairy goats with substrate. And the group only contained the substrate was as control. The effects of 8 yeast fermented liquid on the rumen fermentation were analyzed by measuring the p H of culture fluid, concentration of NH3-N, BCP and VFA in vitro. The results showed that XR4, SC18 and YJ2 reduced the concentration of NH3-N(P0.05) and SC18, YN7 and YJ2 increased the rumen BCP concentrations significantly(P 0.05). YJ2 and YL5 increased the total content of VFA significantly and stabilized the p H of culture fluid. In conclusion SC18, YJ2 and YN7 may promote the rumen fermentation significantly.
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Volatile fatty acids
Flora
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Volatile fatty acids
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Abstract Absorption of volatile fatty acids (VFA) from the rumen of calves 3 to 5 days old was investigated to determine if the ability to assimilate the acids is inherent in the rumen epithelium. The effects of advancing age and diet on VFA transport were examined in calves 6 weeks old fed either solely on milk or on milk and pasture. Absorption was measured by changes in the veno–arterial VFA concentration difference of the rumen after the introduction of test solutions into the fasted, emptied, and rinsed forestomach of anaesthetised animals. Significant increases in the veno–arterial VFA concentration difference of the rumen (P <0.01) were noted in the three groups of calves after the introduction of the acids into the rumen. These increases were similar in the three groups of animals. No differences in VFA assimilation rates were detected between the two groups of older calves. Endogenous sources of circulating VFA and rapid removal of assimilated acids from the peripheral circulation were indicated.
Volatile fatty acids
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Volatile fatty acids
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An experimental study was carried out to investigate the concentrations of volatile (VFA), ammonia and microbial protein production of rumen fluid in sheep given fedd during the day and at night. This study used 12 fat-tailed rams aged 12-18 months and weighed 24,12 ± 25 kg (CV = 10,51%). The rams were fed a complete feed containing 16.64% protein and 68,33% total digestible nutrients (TDN). The rams were allocated into a completely randomised design with 3 treatments and 4 replications. The treatments applied were: T1: day time feeding (6.00 hrs – 18.00 hrs); T2: night time feeding (18.00 hrs – 6.00 hrs); and T3: day and night time feedings (6.00 hrs – 6.00 hrs). The parameters observed were dry matter intake (DMI), rumen VFA concentration, rumen ammonia concentration, rumen rmicrobial protein production and the efficiency of rumen microbial protein production. The results showed that feeding time did not significantly affect (P>0.05) all the parameters observed. Dry matter intake, VFA concentration, ammonia concentration, the microbial protein production of rumen fluid and the efficiency of microbial protein production were 1,073g/d, 49.69 mmol; 4.77 mg N/100 ml, 12,111 g/d and 19.96 g per kg digestible organic matter intake (DOMI), respectively. It is concluded that feeding time did not affect DMI, condition of rumen fluid and rumen microbial protein production in sheep.
Volatile fatty acids
Ammonia production
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ABSTRACT It is now generally accepted that the fermentation of carbohydrates in the rumen gives rise to the formation of large amounts of the lower volatile fatty acids ; but the fact that these acids are absorbed in considerable amounts and at different rates from the rumen into the blood stream has made it clear that in vitro studies of the fermentation processes are necessary in order to ascertain the actual quantities in which they are made available to the ruminant.
Volatile fatty acids
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The rates of production of acetic, propionic, and butyric acids in the normal rumen of a sheep have been measured from the decline in specific activity of these acids in the rumen after introduction of their sodium salts, labelled with 14C. Polyethylene glycol was introduced into the rumen to permit measurement of the rumen volume. The rates of production were: acetic acid 99 m-moles/hr, propionic 44 m-moles/hr, and butyric 21 m-moles/hr.
Volatile fatty acids
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Experiments were conducted to determine the effects of various compounds in an in vitro rumen fermentation system. Antibiotics, steroids, thiamine inhibitors, sulfonamides, a nitrofuran, antihistamines, antibacterials, antifungals, antiprotozoals and miscellaneous compounds were studied in vitro utilizing a hay-grain substrate and inoculum from a steer fed a hay-grain diet. Volatile fatty acids (VFA) were determined following a 6-hr, fermentation period. In general, the antibacterials, antifungals and the antiprotozoals had the most dramatic effects. Bis-[3-tert-butyl-4-(3-dimethylaminopropoxy)-6-methylphenyl]-sulfide dihydrochloride (Su-14,276), 3-{6-Tert-butyl-4-(1-[5-tert-butyl-4-(3-dimethylaminopropoxy)-o-tolyl]-butyl)-m-toloxy}-N, N-di-methyl-propylamine dihydrochloride (Su-15,-412), and 2-[p-(p-chloro-α,α-dimethylbenzyl)-phenoxy]-triethylamine (Su-11,445) increased propionic acid thus lowering the A:P ratio while not affecting total VFA production. These compounds reduced protozoal activity. In contrast to these, 4, 7-phenanthroline-5, 6-dione inhibited VFA production and reduced1 protozoal activity.
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