scholarly journals Absorption and intermediary metabolism of purines and pyrimidines in lactating dairy cows

2015 ◽  
Vol 113 (4) ◽  
pp. 560-573 ◽  
Author(s):  
Charlotte Stentoft ◽  
Betina Amdisen Røjen ◽  
Søren Krogh Jensen ◽  
Niels B. Kristensen ◽  
Mogens Vestergaard ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Degradation Products ◽  
Hepatic Metabolism ◽  
Intermediary Metabolism ◽  
Hepatic Tissue ◽  
N Metabolism ◽  
Net Fluxes ◽  
Purines And Pyrimidines ◽  
Microbial N ◽  
N Pool

About 20 % of ruminal microbial N in dairy cows derives from purines and pyrimidines; however, their intermediary metabolism and contribution to the overall N metabolism has sparsely been described. In the present study, the postprandial patterns of net portal-drained viscera (PDV) and hepatic metabolism were assessed to evaluate purine and pyrimidine N in dairy cows. Blood was sampled simultaneously from four veins with eight hourly samples from four multi-catheterised Holstein cows. Quantification of twenty purines and pyrimidines was performed with HPLC–MS/MS, and net fluxes were estimated across the PDV, hepatic tissue and total splanchnic tissue (TSP). Concentration differences between veins of fifteen purine and pyrimidine nucleosides (NS), bases (BS) and degradation products (DP) were different from zero (P≤ 0·05), resulting in the net PDV releases of purine NS (0·33–1·3 mmol/h), purine BS (0·0023–0·018 mmol/h), purine DP (7·0–7·8 mmol/h), pyrimidine NS (0·30–2·8 mmol/h) and pyrimidine DP (0·047–0·77 mmol/h). The hepatic removal of purine and pyrimidine was almost equivalent to the net PDV release, resulting in no net TSP release. One exception was uric acid (7·9 mmol/h) from which a large net TSP release originated from the degradation of purine NS and BS. A small net TSP release of the pyrimidine DP β-alanine and β-aminoisobutyric acid ( − 0·032 to 0·37 mmol/h) demonstrated an outlet of N into the circulating N pool. No effect of time relative to feeding was observed (P>0·05). These data indicate that considerable amounts of N are lost in the dairy cow due to prominent intermediary degradation of purines, but that pyrimidine N is reusable to a larger extent.

scholarly journals In vitro evaluation of Lactobacillus plantarum as direct-fed microbials in high-producing dairy cows diets

2019 ◽  
Vol 4 (1) ◽  
pp. 214-228 ◽  
Author(s):  
Hugo F Monteiro ◽  
Ana Laura J Lelis ◽  
Virginia L N Brandao ◽  
Andressa Faccenda ◽  
Andre S Avila ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Lactobacillus Plantarum ◽  
Lactate Concentration ◽  
Nutrient Digestibility ◽  
Co2 Production ◽  
Yeast Fermentation ◽  
Ruminal Fermentation ◽  
N Concentration ◽  
N Metabolism

Abstract The objectives of this study were: 1) to compare the effects of live yeast (LY), yeast fermentation product (YFP), a mix of Lactobacillus acidophilus and Propionibacterium freudenreichii (MLP), and Lactobacillus plantarum included as additives in dairy cows’ diets on in vitro ruminal fermentation and gas production (GP); and 2) to evaluate the effects of L. plantarum as direct-fed microbials (DFM) in dairy cows’ diets on in vitro ruminal fermentation, GP, nutrient digestibility, and N metabolism. Three experiments were carried out: Exp. 1 had the objective to compare all additives regarding ruminal fermentation parameters: an Ankom GP system was used in a completely randomized design, consisting of four 48 h incubations, and eight replications per treatment. There were eight treatments: a basal diet without additive (CTRL) or with one of the following additives: LY, YFP, MLP, or L. plantarum at four levels (% of diet Dry Matter (DM)): 0.05% (L1), 0.10% (L2), 0.15% (L3), and 0.20% (L4). In Exp. 2, a batch culture was used to evaluate ruminal fermentation, and CO2 and CH4 production using the same treatments and a similar experimental design, except for having 16 replications per treatment. Based on Exp. 1 and 2 results, Exp. 3 aimed at evaluating the effects of the L. plantarum on ruminal true nutrient digestibility and N utilization in order to evaluate the use of L. plantarum as DFM. The treatments CTRL, MLP, L1, and L2 were used in a replicated 4 × 4 Latin square design using a dual-flow continuous culture system. Data were analyzed using linear and nonlinear regression; treatment means were compared through contrasts, and L treatments in Exp. 1 and 2 were tested for linear, quadratic, and cubic effects. In Exp. 1, all treatments containing additives tended to reduce OM digestibility as well as reduced total volatile fatty acids (VFA) concentration and total GP. The YFP had greater OM digestibility than LY, and MLP treatment had greater total VFA concentration compared to L. plantarum treatments. In Exp. 2, additives reduced CO2 production, and there were no major differences in CH4. In Exp. 3, all additives reduced NH3-N concentration. In conclusion, pH and lactate concentration were not affected in all three experiments regardless of additive tested, suggesting that these additives may not improve ruminal fermentation by pH modulation; and L. plantarum may improve ruminal N metabolism when used as DFM in high-producing dairy cows’ diets, mainly by reducing NH3-N concentration.

Toxic effects of imidacloprid combined with arsenic: Oxidative stress in rat liver

2018 ◽  
Vol 34 (10) ◽  
pp. 726-735 ◽  
Author(s):  
Lakshay Mahajan ◽  
Pawan Kumar Verma ◽  
Rajinder Raina ◽  
Shilpa Sood
Keyword(s):  
Drinking Water ◽  
Oral Administration ◽  
Dose Rate ◽  
Hepatic Metabolism ◽  
Protein Product ◽  
Hepatic Damage ◽  
Hepatic Tissue ◽  
Control Group ◽  
Group I ◽  
Neonicotinoid Insecticide

Imidacloprid (IMI), a newer neonicotinoid insecticide, induces oxidative insult to hepatocytes due to the formation of reactive metabolites during hepatic metabolism. The present study aimed to determine the potentiating effect of arsenic (As) on IMI-induced hepatic damage in Wistar rats. Rats, randomly divided into eight groups with six in each, were subjected to daily oral administration for 28 days. Group I served as control; group II received IMI at the dose rate of 16.9 mg/kg body weight; groups III, IV, and V received As at the dose rate of 50, 100, and 150 ppb, respectively, in drinking water; groups VI, VII, and VIII received both IMI (16.9 mg/kg) and As in drinking water at the rate of 50, 100, and 150 ppb, respectively. Repeated oral administration of IMI or As resulted in significant ( p < 0.05) elevation of plasma phosphatases, transferases, hepatic malondialdehyde, and advanced oxidation protein product levels, but significantly ( p < 0.05) decreased levels of total proteins, thiols, and activities of antioxidant enzymes that indicate oxidation-induced hepatotoxicity. These findings were further corroborated by histological alterations in hepatic tissue of IMI or As-administered rats. The coadministration of both IMI and As in rats produced more severe alterations in these parameters in hepatic tissue. Reduced antioxidant indices and increased hepatic damage biomarkers with pronounced histopathological alterations in hepatic tissue after combined exposure to toxicants indicate potentiating toxic effect of As on IMI-induced hepatotoxicity.

Evaluation of linseed meal for dairy cows: Interaction with grain source on forestomach and whole-tract digestion

1996 ◽  
Vol 76 (2) ◽  
pp. 209-214 ◽  
Author(s):  
P. H. Robinson ◽  
G. R. Khorasani ◽  
J. J. Kennelly
Keyword(s):  
Dairy Cows ◽  
Crude Protein ◽  
Latin Square ◽  
Canola Meal ◽  
Linseed Meal ◽  
Protein Meal ◽  
Protein Status ◽  
Alfalfa Silage ◽  
Pool Sizes ◽  
N Pool

Four Holstein cows in midlactation were fed one of four totally mixed rations differing in grain source (ground barley or cracked corn) and protein meal (solvent-extracted linseed meal or canola meal) in a 12-wk 4 × 4 Latin square experiment. Diets were 10% second-cut alfalfa silage, 50% whole crop oat silage and 40% mixed concentrate on a DM basis. Intake of DM, OM, NDF, starch and crude protein were not influenced by grain source or protein source within grain. Forestomach and whole-tract digestion of these same components were not influenced by treatments, except forestomach digestion of starch which was higher on barley versus corn based diets. Rumen pool sizes of total ingesta DM OM, and NDF were not influenced by treatment, although the rumen pool of NDF tended (P = 0.10) to be higher on barley-based diets. The rumen NAN pool was higher on barley-based diets and this primarily reflected a numerically higher bacterial N pool. Duodenal flow of NAN, bacterial N, residual N and AA protein were also unaffected by treatment although the AA profile of duodenal protein was influenced by both grain source in the diet and source of protein within grain source. Based upon all these results, solvent extracted linseed and canola meals appear to be broadly equivalent as high DIP sources for dairy cows. In addition, animal protein status calculations suggest that the performance of the cows was limited by supplies of DIP on all diets indicating that linseed and canola meals were truly equal as high DIP protein sources for dairy cows. Key words: Canola meal, linseed meal, amino acid, duodenum

Flow of microbial and non-microbial N fractions entering the omasal canal in dairy cows

2001 ◽  
Vol 2001 ◽  
pp. 150-150
Author(s):  
S. Ahvenjärvi ◽  
A. Vanhatalo ◽  
P. Huhtanen
Keyword(s):  
Dairy Cows ◽  
Sampling Technique ◽  
Small Contribution ◽  
Feed Ingredients ◽  
Lactating Dairy Cows ◽  
Protein Supply ◽  
Ruminal Protein Degradability ◽  
N Fractions ◽  
Microbial N

In order to provide accurate estimates of protein supply for lactating dairy cows, the effect of feed ingredients on ruminal protein degradability as well as microbial protein synthesis must be determined. The omasal sampling technique coupled with a triple marker method allows the determination of N flow from the reticulorumen with relatively small contribution from endogenous sources (Ahvenjärvi et al., 2000). The objective of the current study was to assess the contribution of microbial and non-microbial fractions to the total flow of N leaving the rumen of lactating dairy cows fed typical feed ingredients.

scholarly journals Nitrogen and carbon flows between the caecum, blood and rumen in sheep given chopped lucerne (Medicago sativa) hay

1986 ◽  
Vol 55 (2) ◽  
pp. 313-332 ◽  
Author(s):  
R. M. Dixon ◽  
J. V. Nolan
Keyword(s):  
Gastrointestinal Tract ◽  
De Novo ◽  
Specific Radioactivity ◽  
Compartment Model ◽  
Urea Hydrolysis ◽  
Irreversible Loss ◽  
Rumen Microbes ◽  
Made In ◽  
Microbial N ◽  
N Pool

1. Experiments involving 15N and 14C tracers were made in sheep consuming 800 g air-dry chopped lucerne (Merlicugo sativa) hay/d and providing 20.4 g N/d to study N and C flows within the caecal digesta and between the caecum, blood and rumen.2. Continuous infusions of 15N tracers were made into the caecal ammonia, blood urea and rumen NH3 pools. The concentration and enrichment of caecal digesta NH3-N, caecal microbial N, caecal digesta non-urea. non-ammonia-N (NU-NAN), faecal NU-NAN, blood urea-N, rumen digesta NH3-N and rumen bacterial N were estimated at intervals during the infusions. A three-pool open-compartment model was solved to estimate N flows between the caecal digesta NH3-N, blood urea-N and rumen digesta NH3-N pools.3. The rate of irreversible loss from the caecal digesta NH3-N pool was 2.17 (SE 0.623) g N/d. On average 0.9 (SE 0.56) g N/d of caecal digesta NH3-N was derived from blood urea and 0.1 (SE 0.08) g caecal digesta NH3-N/d was apparently derived from the fermentation of undigested rumen microbes in the caecum. The amount of NH3-N produced by proteolysis and deamination of dietary and endogenous N was 1.1 (SE 0.13) g/d.4. There was net incorporation of 0.56 (SE 0.306) g caecal digesta NH3-N/d into caecal microbes. The microbial U synthesized de novo in the caecum was not determined, but 2.9 (SE 0.52) g microbial N/d of both rumen and caecal origin flowed out of the caecum and constituted 0.48 of the NU-NAN flow. The majority (mean 0.83 (SE 0.044)) of this microbial N was excreted in faeces.5. On average 1.8 (SE 0.80) g caecal digesta NH3-N/d were absorbed. Of this NH3-N, 0.92 (SE 0.054) was converted to blood urea, contributing 0.10 (SE 0.031) of blood urea-N. Only 0.012 (SE 0.0041) of rumen digesta NH3-N and 0.005 (SE 0, 0009) of rumen bacterial N were derived from caecal digesta NH3-N.6. Infusions of 14C tracers were made into the caecal digesta bicarbonate, blood bicarbonate, rumen digesta bicarbonate and blood urea pools, and samples were obtained at intervals to determine the specific radioactivity of each pool. A four-pool open-compartment model was solved to estimate C flows between these pools.7. The rate of irreversible loss of blood urea estimated with [14C]urea (17.1 (SE 1.18) g N/d) was greater (P < 0.01) than that estimated with [15N]urea (14.0 (SE 0.87) g N/d).8. Transfer of blood urea to the caecal digesta estimated with 14C tracers (1.4 (SE 0.61) g N/d) was greater (P < 0.01) than that estimated with I5N tracers (0.9 (SE 0.56) g N/d). The estimate of transfer of blood urea to the rumen digesta was also greater with 14C tracers (P < 0.05; 1.7 (SE 0.15) and 1.2 (SE 0.19) g N/d respectively). The urea hydrolysed in the gastrointestinal tract other than in the rumen digesta pool and the caecal digesta pool was 0.56 of total urea hydrolysis when estimated with 14C tracers, or 0.69 when estimated with 15N tracers. Results from previous acute experiments suggested that with three of the four observations made in three sheep in the present experiment the transfer of blood urea to the caecal digesta could have occurred entirely via ileal digesta. Similarly, urea transfer to the rumen digesta could have occurred entirely via saliva.

scholarly journals The Effect of Bovine Somatotropin and Diet on Somatotropin Binding Sites in Hepatic Tissue of Lactating Dairy Cows

1997 ◽  
Vol 80 (6) ◽  
pp. 1085-1091 ◽  
Author(s):  
J.A. Newbold ◽  
R.B. Heap ◽  
C.G. Prosser ◽  
R.H. Phipps ◽  
F. Adriaens ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Binding Sites ◽  
Bovine Somatotropin ◽  
Hepatic Tissue ◽  
Lactating Dairy Cows

Effect of combined acetylmethionine, cyanocobalamin and α-lipoic acid on hepatic metabolism in high-yielding dairy cow

2016 ◽  
Vol 83 (4) ◽  
pp. 438-441 ◽  
Author(s):  
Enrico Fiore ◽  
Laura Perillo ◽  
Giuseppe Piccione ◽  
Matteo Gianesella ◽  
Silvia Bedin ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Lipoic Acid ◽  
Hepatic Metabolism ◽  
Repeated Measure ◽  
Control Group ◽  
Nonesterified Fatty Acids ◽  
Measure Analysis ◽  
Repeated Measure Analysis ◽  
And Control ◽  
Experimental Group

The aim of the study reported in this Research Communication was to investigate the effect of a combined acetylmethionine, cyanocobalamin and α-lipoic acid treatment, on some metabolic parameters of early lactating high-yielding dairy cows. Thirty cows were randomly divided into two groups: experimental group (EG, n = 20) and control group (CG, n = 10). EG received 20 ml of treatment and CG received 20 ml of placebo. The treatments were administered for seven times every 2 d. Blood samples were collected from all cows at 3 time points: 10 ± 2, 30 ± 2 and 50 ± 2 d postpartum. Glucose, β-hydroxybutyrate (BHB), nonesterified fatty acids (NEFA), triglycerides, total cholesterol (TC), alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamiltransferase (GGT), total bilirubin (TB), conjugated bilirubin (CB), total proteins (TP), globulins, albumin and urea concentrations were determined. Two-way repeated measure analysis of variance was applied. Significant differences in the values of glucose, BHB, NEFA, triglycerides, TC, AST and urea were found between EG and CG. Moreover, the increased glucose, TC, ALT, GGT, TP and globulins, and the reduced BHB, NEFA, AST, triglycerides, TB, CB and urea concentrations were evident in both groups, but the changes were more pronounced in EG. Our findings indicate that our treatment positively influenced liver metabolism in high-yielding dairy cows.

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