Ammonia Concentration In Rumen Fluid Research Articles

Effects of hybrid Broussonetia papyrifera silage on growth performance, visceral organs, blood biochemical indices, antioxidant indices, and carcass traits in dairy goats

The crude protein content of hybrid Broussonetia papyrifera silage (HBPS) is close to that of alfalfa hay. In the present study, we substituted alfalfa hay with HBPS in diets for Saanen dairy goats, and tested a possibility of using HBPS as a feedstuff to provide protein. Thirty male Saanen dairy goats (6-months old, body weight 18.85 ± 1.44 kg) were divided into three groups of 10, and randomly assigned to three diets: the control group (CN) fed the basal diet containing 600 g/kg (dry matter (DM) basis) of alfalfa hay, and the other two groups fed the diets with 33 % and 67 % of alfalfa hay being substituted with HBPS, so HBPS accounted for 198 g/kg (LB) and 402 g/kg (HB) of the diet respectively. The experiment lasted for 94 days. Compared with CN, feeding HBPS did not change feed intake, body weight gain, and the visceral organ coefficients (P > 0.05), but reduced the feed conversion ratio and the weight gain cost, particularly on the 198 g/kg HBPS diet (P < 0.05). Serum concentrations of total protein, albumin, and urea-nitrogen in both LB and HB groups and glucose in HB group decreased (P < 0.05), but their values remained within the normal range. Ammonia concentration in rumen fluid was reduced by feeding HBPS (P < 0.05). The serum activity of superoxide dismutase (SOD) was increased and the concentration of malondialdehyde (MDA) decreased (P < 0.05) in both LB and HB groups (P < 0.05), and the SOD activity in longissimus dorsi muscle (LDM) was increased only for LB treatment (P < 0.05). Feeding HBPS had no effect on the carcass traits and water holding capacity in LDM (P > 0.05). In conclusion, HBPS had similar effects to alfalfa hay on the growth performances, visceral organ development, and water holding capacity postmortem, but reduced the feed conversion ratio and the feed cost, and enhanced the antioxidant capacity of animals. Inclusion of 198 g/kg of HBPS in the diet would be a better choice for growing goats. Reduced ammonia concentration in the rumen, urea and protein concentrations in blood suggest dietary protein digestion in the gastrointestinal tract could be affected by feeding HBPS, which is worthy of further investigation.

Effect of grinding process of steam-rolled barley grain on plasma glucose and leucine kinetics and protein synthesis in sheep

ABSTRACTAn isotope dilution method of [U-13C]glucose and [l-13C]leucine was simultaneously conducted to determine the effect of grinding process of steam-rolled barley grain on rates of plasma glucose and leucine turnover and whole-body protein synthesis (WBPS) in sheep. Six adult sheep were assigned to two dietary treatments and the experiment utilized a crossover design for two 21-day periods. The experimental diet was consisted of mixed hay and steam-rolled barley grain (1:1 ratio). Barley grain was treated either with or without grinding (GR diet and SR diet, respectively). Sheep were fed isoenergetically and isonitrogenously in both the treatments. The primed-continuous infusion method of [U-13C]glucose and [1-13C]leucine was simultaneously performed on day 21. The pH and ammonia concentrations in rumen fluid decreased (P < 0.05) and concentrations of total VFA, acetate, propionate and n-butyrate increased (P < 0.05) after feeding. Rates of plasma glucose and leucine turnover and WBPS did not differ between the dietary treatments. It is likely that grinding process of steam-rolled barley grain did not influence plasma glucose and leucine kinetics and WBPS in sheep fed the diets of mixed hay and barley grain at 1:1 ratio.

Nutrient digestibility and rumen fermentation of Thai native purebred compared with Thai native x Lowline Angus crossbred beef cattle

ABSTRACTThe aim of this study was to compare voluntary feed intake, nutrient digestibility, and rumen fermentation of Thai native and Thai native x Lowline Angus crossbred beef cattle fed with different diets. Three different diets consisting of ad libitum rice straw (RS), ad libitum RS supplemented with 0.5% body weight (BW) concentrate (RS+C), and ad libitum Pangola grass hay (PH). The experiment was conducted as 3 × 3 replicated Latin square design with a factorial arrangement of dietary treatment and breed. It was found that Thai native and Thai native x Lowline Angus crossbred beef cattle had comparable roughage intake, BW change, nutrient digestibility, and all parameters from rumen fluid. Cattle fed with different type of feed showed similar roughage intake, BW change, and number of protozoa and fungal zoospore in rumen fluid. However, nutrient intake and digestibility of cattle supplemented with concentrate were higher than those fed the roughage alone. Accordingly, concentration of total volatile fatty acid and proportion of propionic acid in rumen fluid of cattle received concentrate was higher than cattle fed only RS (P < .05) but not for cattle fed with PH. Moreover, the PH-fed group had a higher ammonia concentration in rumen fluid than did the RS-fed group (P < .05). Therefore, the two breeds of beef cattle showed comparable feed response while supplementation of concentrate at 0.50% BW was a useful alternative feeding pattern.

Accuracy of the estimates of ammonia concentration in rumen fluid using different analytical methods

The accuracy of two different methods in measuring the ammonia nitrogen (N-NH3) concentration in rumen fluid were evaluated: a catalyzed indophenol colorimetric reaction (CICR) and the Kjeldahl distillation (KD). Five buffered standard solutions containing volatile fatty acids, true protein, and known ammonia concentrations (0, 3, 6, 12, and 24 N-NH3 mg/dL) were used to simulate rumen fluid. Different ratios (10:1, 7.5:1, 5:1, 2.5:1, 1:1, 1:2.5, 1:5, 1:7.5, and 1:10) of a potassium hydroxide solution (KOH, 2 mol/L) to standard solutions were evaluated by the KD method. The accuracy of each method was evaluated by adjusting a simple linear regression model of the estimated N-NH3 concentrations on the N-NH3 concentrations in the standard solutions. When the KD method was used, N-NH3 was observed to be released from the deamination of true protein (P&lt;0.05), and an incomplete recovery of N-NH3 was observed (P&lt;0.05), except for 7.5:1 and 5:1 ratios of KOH solution to standard solutions (P&gt;0.05). The estimates of the N-NH3 concentration obtained by the CICR method were found to be accurate (P&gt;0.05). After the accuracy evaluation, ninety-three samples of rumen fluid were evaluated by the CICR and KD methods (using the 5:1 ratio of KOH solution to rumen fluid sample), assuming that the CICR estimates would be accurate. The N-NH3 concentrations obtained by the two methods were observed to be different (P&lt;0.05) but strongly correlated (r = 0.9701). Thus, it was concluded that the estimates obtained by the Kjeldahl distillation using a 5:1 ratio of KOH solution to rumen fluid sample can be adjusted to avoid biases. Furthermore, a model to adjust the N-NH3 concentration is suggested.

Effect of feeding dehydrated and ensiled tanniferous sainfoin (Onobrychis viciifolia) on nitrogen and mineral digestion and metabolism of lambs

The effects of tanniferous sainfoin on digestion and metabolism have been investigated in 12 lambs in an incomplete cross-over design (n = 6). Effects of condensed tannins (CT) were evaluated by comparing dehydrated and ensiled sainfoin treated with and without polyethylene glycol (PEG). Dehydrated and ensiled grass-clover mixtures served as controls. The lambs were fed the treatment diets, including a mineral supplement, for 21 d. During the last 7 d excreta, rumen fluid and blood were sampled. The CT of sainfoin decreased rumen fluid ammonia concentration (p < 0.001) and increased the plasma concentration mainly of essential amino acids (p < 0.001). Body retention of phosphorus, calcium and magnesium was lower with sainfoin compared to PEG-treated sainfoin (p < 0.05). Sainfoin without PEG resulted in lower digestibilities of organic matter and neutral detergent fibre than sainfoin with PEG and the grass-clover mixture (p < 0.001). Ensiling of sainfoin led to the lowest N-retention. In conclusion, the reduction in ruminal ammonia and urine-N losses by sainfoin CT did not improve N-retention.

Nutrient metabolism in the rumen and milk production in cows fed on grass-silage and fresh grass based diets

The main objective of this experiment was to quantify and compare the flows of nitrogen (N), microbial N (MN) and amino acids (AA) to the small intestine of lactating dairy cows on fresh grass and grass-silage based diets. Four cows fitted with rumen and duodenal cannulae were subjected to the following four treatments in a Latin Square design, (1) grass offered ad libitum (G), (2) grass offered ad libitum+4 kg of a by-product based concentrate (C) per head per day (G4), (3) wilted silage offered ad libitum+C (W4) and (4) unwilted silage offered ad libitum+C (UW4). The double marker technique was used to measure flows to the duodenum with Yb and Co as the solid and liquid phase markers, respectively. Purines were used as microbial markers. Total dry matter (DM), organic matter (OM) or N intakes did not differ significantly between treatments. Flows of N, NAN, MN, lysine or methionine were not significantly different between G and G4. Flow of N was significantly higher on G4 compared to W4 ( P<0.05) and UW4 ( P<0.001). Flow of N on W4 was significantly higher than on UW4 ( P<0.01). Non-ammonia N (NAN) and non-ammonia non-microbial N (NANMN) flows were higher on G4 compared to W4 ( P<0.05) and UW4 ( P<0.001), and the flow of NAN was significantly higher on W4 compared to UW4 ( P<0.01). There was no significant difference between treatments in the quantity of MN flowing per kg of organic matter apparently digested (OMAD) or organic matter truly digested (OMTD) in the rumen but flow on UW4 was numerically lower than on the other treatments. Flows of total AA were significantly higher on G4 compared to UW4 ( P<0.01). Lysine and methionine flows as a proportion of total AA were not significantly different between G4, W4 and UW4 or between G and G4 ( P>0.05). Propionic acid concentrations were significantly higher, while acetic acid concentrations were significantly lower on G4 compared to W4 and UW4 ( P<0.01) while concentrations were not significantly different between G and G4 ( P>0.05). Ammonia concentrations in rumen fluid on W4 and UW4 were substantially higher than the concentrations on G4. It is concluded that in general flows to the duodenum of N and AA are higher on a fresh herbage based diet than on an unwilted grass-silage based diet. Wilted silage results in improved flows of MN compared to unwilted silage.

Efficacy of plant extracts rich in secondary constituents to modify rumen fermentation

Three plant extracts with different secondary constituents were simultaneously evaluated in an eight fermenter rumen simulation technique (Rusitec) for their effects on ruminal fermentation pattern. Specifically, a Yucca schidigera extract containing the saponin compound sarsaponin was supplied at three concentrations (1, 20 and 100 mg sarsaponin/kg dry matter (DM)) and was compared to a Castanea sativa wood extract containing hydrolysable tannins (0.5 and 2.5 g tannins/kg) and pure sulphonate-free lignin (2.5 g/kg). The supplements were added to a basal diet (grass silage, barley grain, grass hay) with a low crude protein (CP) content. These diets were compared to the same, unsuppplemented basal diet (control) and to a diet with additional soybean meal providing protein according to recommendations for dairy cow diets. The control diet and the soybean meal diet differed in rumen fluid ammonia concentration by 15% (13.6 mmol/l versus 16.0 mmol/l). Relative to the control diet, the high doses of the saponin-rich and the tannin-rich extract reduced the rumen fluid ammonia level by up to 21%. There was a tendency for elevated levels of apparent protein degradation during 48 h of fermentation, suggesting that the effect of the extracts on ammonia probably did not result from suppression of microbial protein degradation. Bacterial and protozoal counts in rumen fluid were not influenced by dietary treatments. Substantive effects of the saponin-rich and tannin-rich products on ruminal nitrogen metabolism were observed only at doses exceeding those recommended by the manufacturers.

Effects ofFusarium-toxincontaminated wheat in ruminant nutrition

An experiment was carried out to examine the effects of aFusarium-contaminated wheat grain as a component of the concentrate portion (10 mg deoxynivalenol and 0.76 mg zearalenone, ZON, per kg dry matter) on performance of growing bulls, and on carry over of ZON into tissues and body fluids. In a second study, rumen physiological parameters were investigated in wethers equipped with rumen fistulae. Moreover, the influences of a detoxifying agent (Mycofix®, MP, Biomin GmbH, Herzogenburg, Austria) were considered as an additional experimental factor beside the contamination of the wheat (uncontaminated control wheat,Fusarium-toxincontaminated wheat).The fattening experiment with bulls (n=14 per treatment) covered the live weight range between 244 kg and 460 kg. Daily dry matter intake and live weight gain (kg per animal and day) were 7.40, 7.52, 7.51 and 7.49 and 1.367, 1.296, 1.380 and 1.307 for bulls fed the unsupplemented control wheat, the supplemented control wheat, the unsupplemented andFusarium toxin contaminated wheat and the supplementedFusarium toxin contaminated wheat, respectively. Concentration of ZON and its metabolites in edible tissues were lower than the detection limits of the applied HPLC-method.The results of the rumen physiological investigations revealed that the molar ratios of short chained volatile fatty acids and ammonia concentration in rumen fluid remained unchanged in response to dietary treatments whereas the addition of MP to the diets buffered the postprandial decrease in rumen pH.

Lasting effects of monensin on rumen and caecal fermentation in sheep fed a high grain diet

Eventual adaptation of rumen fermentation to monensin feeding has been studied in two rumen and caecal fistulated sheep fed 150 g of hay and 500 g of concentrates at 9.00 h and 16.00 h. After a control period of 23 days, a dose of 60 mg of monensin was infused for 6 days. This period was followed by a 29 day period during which 50 mg were administered. Monensin was introduced into the rumen as an aqueous suspension, just prior to feeding (with the 60 mg dose: before the morning feeding; with the 50 mg dose: 25 mg twice daily before each feeding). The following rumen fermentation parameters were determined in vivo: methane expelled through the fistula for 6 h per day, pH, total volatile fatty acids (VFA) concentration, molar proportions of VFA, lactate and ammonia concentration in rumen fluid sampled 2 h after monensin administration, and in sacco degradability of hay (24 h). In vitro incubations of 24 h were carried out with caecal contents sampled continuously from one sheep between 9.30 h and 10.00 h. Methane production in the rumen (in vivo) and in the caecum (in vitro) was decreased by monensin feeding. The molar proportion of propionate in the rumen was increased, while acetate and butyrate percentages were sometimes lowered. Total VFA concentration was not significantly decreased while ammonia concentration was lowered. Production of propionate in the caecum in vitro was stimulated by monensin administration while methanogenesis and acetate production were inhibited. The in sacco degradability of hay (dry matter) was not affected by monensin administration. These modifications of rumen and caecum fermentation persisted as long as monensin was given, indicating that on a high grain diet, no adaptation of rumen fermentation to the ionophore was observed. On the other hand, the incubations with caecal contents showed clearly that monensin caused analogous and persistent changes in fermentation pattern in the lower gastro-intestinal tract also.

Nitrogen digestion and metabolism in sheep consuming diets containing contrasting forms and levels of N.

Nitrogen kinetics were studied in six sheep (45-55 kg live weight) consuming either a high-N grass silage or a low-N dried grass made from swards of perennial ryegrass (Lolium perenne). The diets were fed hourly at a level of 600 g dry matter/d and supplied 19.5 and 11.0 g N/d respectively. The amounts of organic matter (OM) consumed and flowing at the duodenum and ileum and excreted in the faeces were similar (P greater than 0.05) with both diets. Each diet supplied 23 g digestible OM/d per kg live weight 0.75, which was sufficient to maintain body-weight. There were no differences (P greater than 0.05) between diets in rumen fluid volume, fractional outflow rate of fluid from the rumen, total concentration of volatile fatty acids or molar proportion of acetate in the rumen. The pH and molar proportion of propionate in rumen fluid were higher (P less than 0.01), and molar proportion of butyrate lower (P less than 0.001) when the silage was given. There was a net loss of N (4.0 g/d) between mouth and duodenum when the silage was consumed but a net gain (5.5 g/d) when the dried grass was consumed. As a result, total non-ammonia-N (NAN) flow at the duodenum did not differ (P greater than 0.05) between diets. Rumen microbial NAN flow at the duodenum, based on 15N as the marker, also did not differ (P greater than 0.05) between diets but the efficiency of microbial N synthesis in the rumen (g/kg OM apparently digested) was higher (P less than 0.05) with the dried grass. When the sheep were consuming silage they had a higher concentration of ammonia in rumen fluid (P less than 0.01), a higher rate of irreversible loss of ammonia from the rumen (P less than 0.05) and a higher rate of absorption of ammonia across the rumen wall (P less than 0.01). The rate of absorption was found to be more closely related to the unionized ammonia concentration in rumen fluid (r2 0.85) than to the total ammonia concentration (r2 0.36). Endogenous N entry into the forestomachs was calculated to be 5.5 g/d when the silage was given and 9.4 g/d when the dried grass was given, of which 1.7 and 3.5 g/d respectively were in the form of urea. Thus, approximately 4-6 g N/d were derived from non-urea materials.(ABSTRACT TRUNCATED AT 400 WORDS)

Urea synthesis and degradation in sheep given pelleted-grass diets containing flaked barley.

1. Three sheep fitted with rumen and oesophageal cannulas were given hourly the following diets in successive experiments: 1000 g pelleted-grass cubes/d (diet A) and 700 g pelleted-grass cubes plus 300 g flaked barley/d (diet B).2.During the final week of each 4-week dietary regimen, a balance trial was conducted and on separate days each sheep was continuously infused with [14C]urea and NaH14CO3 intravenously and NaH14CO3 intraruminaily. C transfer rates between blood urea, blood bicarbonate and rumen bicarbonate pools were calculated from the specific radioactivity of urea and bicarbonate sampled and isotope infusion rate during each experimental period. In the same period, an oral infusion of 51Cr-EDTA was maintained and salivary flow rate and composition determined from samples collected from the oesophageal fistula.3. The inclusion of flaked barley in the pelleted-grass diet significantly (P &lt; 0·01) increased the apparent digestibility of organic matter (0·069), apparently digestible organic matter intake and nitrogen balance, and increased the efficiency cf dietary N utilization from 0·059 (diet A) to 0·290 (diet B). Increased N balance was the result of a significant (P) &lt; 0·01 reduction in urinary urea excretion.4. The rumen fluid of sheep given diet A had higher pH and bicarbonate concentrations but lower butyric acid concentrations than that of sheep given diet B. There was no significant effect of diet on total volatile fatty-acid or ammonia concentrations in rumen fluid, or on osmolaiity and rumen fluid dilution rate. The irreversible loss of bicarbonate from rumen fluid was markedly increased when flaked barley was included in the diet, with most of the loss occurring directly from rumen fluid.5. Sheep given diet A had higher salivary secretion rates (18·8 l/d) than those given diet B (12·7 l/d), and with the exception of urea, there was no effect of diet on the concentrations of total N, protein N, alpha;-amino-N, uric acid-N or bicarbonate in saliva. Urea concentrations in saliva were significantly correlated (r20·64) with blood urea concentrations, but not with salivary flow rate. Salivary secretions contributed 2·2 and 1·4 gN/d to the rumen of sheep given diets A and B respectively, with urea forming only 45–33% of the total N secreted.6. When flaked barley was included in the pelleted-grass diet, there was a significant (P &lt; 0·01) decrease in urea synthesis rate (diet A 20·0 g N/d, diet B 9·7 g N/d), a significant increase in amount (diet A 2·3 g N/d. diet B 3·0 g N/d) and proportion (diet A 0·024, diet B 0·57) of recycled urea degraded in the rumen. The permeability of the rumen wall to urea was also significantly increased in sheep given the flaked barley diet (diet A 1·35 g N/d, diet B 2·45 g N/d).7. A model of urea metabolism in sheep given each diet is described, and the mechanisms by which flaked barley inclusion increased urea recycling to the rumen and the efficiency of dietary N utilization are discussed.

EFFECTS OF VOLATILE FATTY ACID TREATMENT ON THE PROTECTION OF PROTEIN IN THE RUMEN

The increase of ammonia in rumen fluid in response to a single dose of protein supplement was used to assess microbial degradation of proteins in the rumen of sheep and cattle held without feed for about 16 h. The administration of 300 g of soybean meal and promine (50:50) pellets (9.4-mm diam) via the rumen fistula of sheep resulted in a rectilinear increase in ammonia concentration in rumen fluid over a 5-h period. The rates of increase of rumen ammonia from isonitrogenous amounts of untreated and 20% volatile fatty acid (VFA)-treated protein pellets were 9.4 and 1.5 mM/h, respectively. The decrease in the rate of protein degradation was proportional to the amount of VFA incorporated and the size of particles in the supplement. When a protein supplement containing common feed ingredients (soybean meal, herring meal and ground barley) was treated with 15% VFA and fed in meal form or as pellets to sheep and cows, the rumen ammonia was maintained for about 10 h at a lower concentration than that after feeding untreated preparations. Treatment of proteins with VFA may be useful in protecting proteins from microbial degradation in the rumen and allowing provision of supplemental protein to the lower digestive tract.