Ruminal Metabolism Research Articles

Evaluation of Trace Element Levels and Antioxidant Metabolism in Cattle with Cutaneous Papillomatosis

Background: Cutaneous papillomas are benign proliferative neoplasms. The aetiology and pathogenesis of the disease are very complex. Papillomatosis lesions can be detected anywhere on the body, frequently appearing on the surface of the head, neck, teats, udder, external genital mucosa and upper part of the gastrointestinal tract. The disease is not life threatening but due to loss of productivity, owners often cull animals with papillomatosis. The relationships between trace elements, heavy metals and cancer are still researching. The aim of this study was the evaluation of the relationships between trace elements and antioxidant metabolism, and cutaneous papillomatosis, in cattle.Materials, Methods & Results: Eleven cattle with cutaneous papillomatosis and 10 healthy cattle constituted the study group and control group, respectively. Clinical examinations were performed on all animals. Blood samples were collected and Cr, Cu, Fe, Mg, Mn, Se, Zn, As, B, Ni, Si and Co levels were determined. The analyses were conducted with an inductively coupled plasma-optical emission spectrophotometer. In addition, catalase (CAT), glutathione (GSH), malondialdehyde (MDA) and ceruloplasmin (Cp) concentrations were measured. The Ni, Si and MDA levels of the study group were significantly higher than those of the control group (P < 0.05) but the Se levels of the study group were significantly lower than in the control group (P < 0.05). The normality of the data was determined with the Shapiro-Wilk Test and the Independent Samples t-Test or Mann-Whitney U test was used for statistical comparison of the groups.Discussion: Trace elements are essential components of biological systems. The levels of trace elements, such as Cu, Co, I, Se, Zn and Mn, which are affected by grazing activity, influence ruminants’ reproductive performance and other production parameters. The elements Al, As, Cr, Ni and Sn are also presumed to be essential for ruminant metabolism, although sufficient research data are not available. In the present study, Cr, Cu, Fe, Mg, Mn, Zn, As, B and Co levels were not significantly different between the papilloma and control groups. Se is an important trace element for skin health. This study revealed a mean serum Se level in animals with papillomatosis that was significantly lower than in the healthy group. Although the mode of anticancer activity of Se is not clear, some factors, such as antioxidant protection, improved immune system surveillance, carcinogen detoxification, modulation of cell proliferation and inhibition of tumour cell invasion and angiogenesis, are important. Ni is classified as a toxic heavy metal. In addition, it could be carcinogenic to humans. Ni level was two times higher in the papillomatosis group than in the healthy animals, in the present study. This result may indicate that Ni has a role in the genesis of papillomatosis in cattle. Si injection can cause inflammation, granulomas and cancer. There are few reports about Si levels in animals and the significant difference in the Si levels in cattle with cutaneous papillomatosis reported in this study may be a new indicator for the disease. The skin contains antioxidant molecules that include GSH, alpha-tocopherol or vitamin E, ascorbic acid or vitamin C, glutathione peroxidases, glutathione reductase, glutathione S-transferases (GSTs), superoxide dismutases (SODs), CAT and quinine reductase. There is strong interaction between ROS and/or their oxidant products and antioxidant molecules in the skin. In this study, although MDA levels were higher in the study group than in the control group, there was no significant difference between the groups in their CAT levels, and also in the GSH and CP levels. In conclusion, these results may evidence the systemic effects of papillomatosis on trace element levels and on oxidant metabolism in cattle.

Influence of supplementing a methionine derivative, N-acetyl-l-methionine, in dairy diets on production and ruminal fermentation by lactating cows during early to mid lactation

The present study investigated production responses and ruminal fermentation characteristics of lactating dairy cows when supplemented with N-acetyl-l-Met (NALM) as a source of rumen-protected Met in metabolizable protein (MP)-deficient (MPD) or MP-adequate diet (MPA). Eight lactating dairy cows (53 ± 10.4 d in milk, average ± standard deviation) were blocked by parity and days in milk, and the experiment was performed in a replicated 4 × 4 Latin square design. Within each square, cows were randomly assigned to a sequence of 4 diets during each of the four 21-d periods (14 d of treatment adaptation and 7 d of data collection and sampling). A 2 × 2 factorial arrangement was used; MPD or MPA was combined without or with NALM: MPD without NALM, MPD with NALM (MPD+NALM), MPA without NALM, and MPA with NALM (MPA+NALM). A NALM product was supplemented in the MPD+NALM and the MPA+NALM at 30 g/cow per d. Supplementation of NALM did not affect dry matter intake (DMI) and milk yield regardless of MP concentration. In addition, supplementing NALM resulted in a similar milk true protein concentration and yield. In contrast, NALM supplementation increased milk fat concentration and yield and 3.5% fat-corrected milk yield and tended to increase energy-corrected milk yield regardless of MP difference. Additionally, trends were observed for increased 3.5% fat-corrected milk yield/DMI and energy-corrected milk yield/DMI, and the positive effects were greater under the MPA than the MPD diet, resulting in trends toward interactions between MP and NALM. Dietary treatments had similar effects on ruminal fermentation characteristics and microbial protein yield. Plasma concentration of Met increased under the MPD but not the MPA diet, leading to an MP × NALM interaction. Overall results in the current study suggest that NALM exerted a minor influence on ruminal metabolism, but increased milk fat concentration, resulting in increases in milk fat yield and feed efficiency. Yet, potential effects of NALM on intermediary metabolism between the gastrointestinal tract, the liver, and the mammary gland need to be explored to understand utilization efficiency for production of dairy cows.

Urea Metabolism and Regulation by Rumen Bacterial Urease in Ruminants – A Review

Abstract Urea is used as non-protein nitrogen in the rations of ruminants as an economical replacement for feed proteins. Urea transferred from the blood to the rumen is also an important source of nitrogen for rumen microbial growth. It is rapidly hydrolyzed by rumen bacterial urease to ammonia (NH3) and the NH3 is utilized for the synthesis of microbial proteins required to satisfy the protein requirements of ruminants. Urea has commonly become an accepted ingredient in the diets of ruminants. In recent decades, urea utilization in ruminants has been investigated by using traditional research methods. Recently, molecular biotechnologies have also been applied to analyze urea-degrading bacteria or urea nitrogen metabolism in ruminants. Combining traditional and molecular approaches, we can retrieve better information and understanding related to the mechanisms of urea metabolism in ruminants. This review focuses on urea utilization in ruminants and its regulation by rumen bacterial urease in the host. The accumulated research provides foundations for proposing further new strategies to improve the efficiency of urea utilization in ruminants.

In vitro ruminal biohydrogenation of eicosapentaenoic (EPA), docosapentaenoic (DPA), and docosahexaenoic acid (DHA) in cows and ewes: Intermediate metabolites and pathways

A great deal of uncertainty still exists about intermediate metabolites and pathways explaining the biohydrogenation (BH) of 20- and 22-carbon polyunsaturated fatty acids (PUFA). Therefore, this study was conducted to provide further insight into the ruminal metabolism of 20:5 n-3 (EPA), 22:5 n-3 (DPA), and 22:6 n-3 (DHA), the main n-3 PUFA present in the marine lipids used in dairy ruminant feeding, and to examine potential differences between bovine and ovine. To meet this aim, we investigated the 20- and 22-carbon metabolites accumulated during in vitro incubation of EPA, DPA, and DHA with rumen inocula from cows and ewes. The PUFA were added at a dose of 2% incubated dry matter and digesta samples were analyzed after 24 h of incubation using complementary gas-liquid chromatography of fatty acid methyl esters and gas chromatography-mass spectrometry of 4,4-dimethyloxazoline derivatives. Results suggested that the main BH pathway of EPA and DPA would proceed via the reduction of the double bond closest to the carboxyl group (cis-5 in EPA and cis-7 in DPA); curiously, this mechanism seemed of much lower importance for DHA. Thus, DPA would not be a major intermediate product of DHA and their BH might actually follow separate pathways, with the accumulation of numerous unique metabolites in each case. A principal component analysis supported this hypothesis, with a clear separation between PUFA treatments in the score and loading plots. Within EPA and DPA groups, cow and ewe samples loaded separately from each other but not distant. No conjugated 20:5, 22:5, or 22:6 isomer compatible with the initial product of EPA, DPA, or DHA metabolism, respectively, was identified in the ruminal digesta, although this would not unequivocally exclude their transient formation. In this regard, results from DPA incubations provided the first indication that the metabolism of this very long chain PUFA may involve the formation of conjugated double bond structures. The BH of EPA, DPA, and DHA resulted in the appearance of several tentative trans-10-containing metabolites, showing a general trend to be more abundant in the digesta of ewes than in that of cows. This finding was speculated to have some relationship with the susceptibility of dairy sheep to marine lipid-induced milk fat depression. Differences in the relative proportion of intermediate products would also suggest an influence of ruminant species on BH kinetics, with a process that would likely be slower and less complete in cows than in ewes.

Inclusion of copaiba oil (Copaifera sp.) as additive in supplements for cattle on pasture

SUMMARY This study analyzed the effect of including copaiba oil as an additive for cattle supplemented on pasture, during the dry season. Four crossbred steers, castrated, with 245 ± 25 kg, aged about 18 months, fitted with permanent rumen cannula; were randomly assigned to a 4×4 Latin square. All animals were housed in individual paddocks (0.3 ha), uniformly covered with Brachiaria brizantha cv Marandu, with through and drinking fountain; and were given a concentrate at 500g/100 kg BW containing 380 g/kg crude protein (%DM). The copaiba oil was added to the supplement as a spray, in the proportions of 0, 0.5; 1.0 and 1.5 g/kg DM intake. Spraying supplementation was performed daily at the time of supply of the supplement. Data of intake and digestibility of nutrients, ruminal pH; ruminal ammonia nitrogen, and microbial protein synthesis were tested by analysis of variance and polynomial regression, adopting a significance level of 5%. The inclusion of copaiba oil quadratically affected total dry matter intake (P=0.030) and CP digestibility (P=0.043), without altering ruminal metabolism (P>0.05) and microbial protein synthesis (P>0.05) of the animals kept on pasture.

A Review on the Role of Chromium Supplementation in Ruminant Nutrition—Effects on Productive Performance, Blood Metabolites, Antioxidant Status, and Immunocompetence

With the increase in the global herd, the use of metabolic modifiers has become an important area for many researchers looking for a supraphysiological diet to improve production parameters. For improving the performance of high yielding cows, the optimal balance of all nutrients including microminerals is important. Chromium (Cr) is one of the important micronutrients which plays an important role in metabolism of ruminants. Experimental studies have found that Cr could change performance, immune responses, glucose and fatty acid metabolism, and antioxidant status in dairy cows. In some studies, Cr supplementation improved dry matter intake, milk production, and milk composition of dairy cows in the early, mid, or late stage of lactation. Also, in some studies, performance of growing animal, immune response, and some blood parameters responded positively to Cr supplementation. In conclusion, the effects of Cr supplementation on performance of ruminants are inconsistent; however, its long-term effects on health, productivity, immune system, and antioxidant activity of ruminants still need to be investigated.

Effects of chronic dexamethasone administration on hyperglycemia and insulin release in goats

BackgroundDexamethasone (Dex), a synthetic glucocorticoid, is among the most commonly used drugs worldwide in animals and humans as an anti-inflammatory and immunosuppressive agent. GC has profound effects on plasma glucose level and other metabolic conditions. However, the effect of prolonged use of Dex on glucose metabolism in ruminants is still unclear.ResultsTen goats were randomly assigned to two groups: the control goats were injected with saline, and the Dex-treated goats were intramuscularly injected daily for 21 d with 0.2 mg/kg Dex. The results showed that plasma glucose and insulin concentrations were significantly increased after Dex administration (P < 0.05). Additionally, the content of hepatic glycogen was also markedly increased in Dex-treated goats (P < 0.01), while the content of glycogen in dorsal longissimus was unchanged by Dex (P > 0.05). The expression of several key genes, involved in blood glucose regulation, was detected by real-time PCR in the small intestine, skeletal muscle and liver. The expression of glucose transporter type 2 (GLUT2), sodium-glucose transporter 1 (SGLT1) and sodium-potassium ATPase (Na-K/ATPase) in the small intestine were generally increased by Dex, and GLUT2 mRNA expression was significantly up-regulated (P < 0.05). In liver, the expression of genes involved in gluconeogenesis including glucose-6-phosphatase catalytic subunit (G6PC), cytosolic form of phosphoenolpyruvate carboxykinase (PCK1) and pyruvate carboxylase (PC), were significantly down-regulated by Dex. However, the protein expression levels of PCK1 & PCK2 were significantly increased by Dex, suggesting a post-transcriptional regulation. In dorsal longissimus, the mRNA expression of genes associated with gluconeogenesis and the insulin signaling pathway were generally up-regulated by Dex, but the mRNA expression of two markers of muscle atrophy, namely F-box protein 32 (FBXO32/Atrogin1) and muscle RING-finger protein 1 (MuRF1), was not altered by Dex.ConclusionsTaken together, these results indicate that chronic administration of a low dosage of Dex induces hyperglycemia mainly through gluconeogenesis activation in the goat liver.

Effects of gallic acid on in vitro rumen fermentation and methane production using rumen simulation (Rusitec) and batch-culture techniques

Two experiments were conducted to investigate the effects of adding gallic acid (GA) to ruminant diets on long- and short-term in vitro rumen fermentation and methane (CH4) production, and to test possible interactions between GA and ethanol on fermentation. The first experiment was conducted using the rumen simulation technique (Rusitec), as a completely randomised block design with four replications and the following four doses of GA: 0, 5, 10 and 20 mg GA/g dry matter (DM). Ethanol was used in all treatments to increase the solubilisation of GA in rumen fluid. The experimental period lasted 16 days, of which the first 7 days were for adaptation and the subsequent 9 days were for sampling. The second experiment was a 48-h batch-culture incubation conducted as a completely randomised design with a 4 (GA dose; 0, 10, 20, and 40 mg GA/g DM) × 2 (with or without ethanol) arrangement of treatments. In the Rusitec experiment, addition of GA up to 20 mg/g DM did not affect DM disappearance (DMD), organic matter (OM) disappearance, neutral detergent-fibre disappearance (NDFD), acid detergent-fibre disappearance (ADFD) or starch disappearance (P &amp;gt; 0.05), but crude protein disappearance was linearly decreased (P = 0.04) from 78.3% to 72.0%. Daily gas production and CH4 production expressed as mL/g DM and mL/g DMD were not affected by addition of GA (P &amp;gt; 0.05). Addition of GA up to 20 mg/g DM increased butyrate and isovalerate production (P &amp;lt; 0.05) and tended to increase isobutyrate (P = 0.09) and decrease heptanoate production (P = 0.07). In the batch-culture experiment, adding GA up to 40 mg/g DM linearly increased 48-h DMD, NDFD and ADFD (P &amp;lt; 0.05) and decreased (P &amp;lt; 0.05) CH4 expressed as mL/g DMD, mL/g NDFD and mL/g ADFD. Methane production was decreased after 24 h and 48 h only when GA was added at 10 mg/g DM without ethanol. Fermentation liquid pH and concentration of ammonia-nitrogen (ammonia-N) were also reduced (P &amp;lt; 0.05) with an increasing concentration of GA. Treatments with ethanol notably enhanced 48-h DMD, NDFD, ADFD, gas production (mL/g DM, mL/g OM or mL/g DMD), CH4 production (mL/g DM, mL/g DMD or mL/g NDFD), total volatile fatty acid concentration, the acetate:propionate ratio, acetate, valerate, isovalerate and caproate molar proportions (P &amp;lt; 0.01) and decreased propionate, butyrate and isobutyrate molar proportions (P &amp;lt; 0.01). Significant dose of GA × ethanol interaction was observed only for acetate molar proportion (P = 0.03). In conclusion, our study suggests that the beneficial effects of GA on feed digestion and CH4 production may be short term, while improvements in N metabolism may be sustained over the long term. It may be useful to conduct long-term in vivo studies using a range of diets and doses to verify whether GA can be used as a feed additive to mitigate enteric CH4 production and improve N metabolism of ruminants.

Effects of Condensed and Hydrolyzable Tannins on Rumen Metabolism with Emphasis on the Biohydrogenation of Unsaturated Fatty Acids.

The hypothesis that condensed tannins have higher inhibitory effect on ruminal biohydrogenation than hydrolyzable tannins was tested. Condensed tannin extract from mimosa (CT) and hydrolyzable tannin extract from chestnut (HT) or their mixture (MIX) were incorporated (10%) into oil supplemented diets and fed to rumen fistulated sheep. Fatty acid and dimethyl acetal composition of rumen contents and bacterial biomass were determined. Selected rumen bacteria were analyzed by quantitative real time PCR. Lower ( P < 0.05) rumen volatile fatty acids concentrations were observed with CT compared to HT. Moreover, lower concentration ( P < 0.05) of Fibrobacter succinogenes, Ruminococcus flavefaciens, Ruminococcus albus, and Butyrivibrio proteoclasticus were observed with CT compared to HT. The extension of biohydrogenation of 18:2n-6 and 18:3n-3 did not differ among treatments but was much more variable with CT and MIX than with HT. The trans-/ cis-18:1 ratio in bacterial biomass was higher ( P < 0.05) with HT than CT. Thus, mimosa condensed tannins had a higher inhibitory effect on ruminal metabolism and biohydrogenation than chestnut hydrolyzable tannins.

Effect of dietary fish oil supplements alone or in combination with sunflower and linseed oil on ruminal lipid metabolism and bacterial populations in lactating cows

Fish oil (FO) alters ruminal biohydrogenation causing trans fatty acid (FA) intermediates to accumulate, but the effects of 18-carbon polyunsaturated FA supply on ruminal long-chain FA metabolism and microbial communities in cattle fed FO are not well established. Four cows fitted with rumen cannula were used in a 4 × 4 Latin square with 21-d experimental periods to evaluate the effects of FO alone or in combination with plant oils high in 18:2n-6 or 18:3n-3 on rumen microbial ecology and flow of FA at the omasum. Treatments comprised a basal grass silage-based diet containing no additional oil (control) or supplements of FO (200 g/d) or FO (200 g/d) plus 500 g/d of sunflower oil (SFO) or linseed oil (LFO). Flow of FA was determined using the omasal sampling technique. The relative abundance of key biohydrogenating bacteria was assessed by quantitative PCR on 16S rRNA genes in omasal digesta. Fish oil-supplemented treatments increased the amounts of trans-18:1, trans-18:2, and 20- to 22-carbon polyunsaturated FA escaping the rumen. Relative to the control, oil supplements had no effect on the amount of 18:0 leaving the rumen, but LFO decreased the flow of 18:0 at the omasum compared with SFO. Both SFO and LFO increased trans-18:1 relative to FO, whereas LFO resulted in the highest trans-18:2 and 20- to 22-carbon FA flow. Supplements of FO plus plant oils shifted biohydrogenation toward trans-10 18:1 formation. Compared with FO alone, the ruminal metabolism of 22:6n-3 in the rumen of lactating cows is more extensive on diets containing higher amounts of 18-carbon polyunsaturated FA. However, the biohydrogenation of 22:5n-3 was less extensive in LFO than SFO, but showed no difference between FO and diets containing plant oils. Ruminal outflow of 20:5n-3 was not altered when plant oils were added to FO. Alterations in the amount of intermediates at the omasum or ruminal biohydrogenation pathways were not accompanied by major changes in analyzed bacterial populations. In conclusion, dietary supplements of FO alone or in combination with plant oils increase the amount of biohydrogenation intermediates containing 1 or more trans double bonds escaping the rumen, which may have implications for host metabolism and the nutritional quality of ruminant foods.

Air-Dried Brown Seaweed, Ascophyllum nodosum, Alters the Rumen Microbiome in a Manner That Changes Rumen Fermentation Profiles and Lowers the Prevalence of Foodborne Pathogens.

The use of Tasco (air-dried Ascophyllum nodosum) as a feed supplement for ruminants has been reported to affect rumen fermentation and reduce Escherichia coli O157:H7 shedding in feces, but the mode of action behind this phenomenon is unclear. In this study, the effects of four Tasco levels (0, 1, 3, and 5%) on rumen microbiota and rumen/fecal E.coli O serogroups in rams were investigated. Rumen total bacteria and archaea were linearly reduced (P < 0.001) and protozoa were linearly increased (P < 0.001) by increasing levels of Tasco. The relative abundances of seven bacterial species and one protozoal species differed among Tasco levels. With Tasco, 14 predicted metabolic pathways were enriched while only 3 were suppressed. A lower ruminal butyrate concentration is possibly associated with enrichment of the "butanoate metabolism" pathway in Tasco-fed rams. The ruminal total E.coli population was linearly reduced (P < 0.001) by Tasco. Supplementation with Tasco only completely eliminated O121 in the rumen and feces, and higher levels of Tasco (3 and 5%) reduced fecal shedding of serogroups O45, O103, and O111 even though these serogroups were present in the rumen. Our results suggest that Tasco effectively reduced pathogenic E.coli but had only minimal impacts on rumen fermentation in rams. IMPORTANCE Maintaining product safety and reducing the carbon footprint of production are two sustainability goals of the livestock industry. The objective of this study was to study the impact of Tasco, a product derived from the brown macroalga Ascophyllum nodosum, on the rumen microbiome and its function. The inclusion of Tasco altered both rumen and fecal microbiota levels without affecting rumen fermentation. Tasco reduced fecal Escherichia coli populations and specifically reduced the prevalence of Shiga toxin-producing E.coli O45, O103, O111, and O121 in feces. The findings of this study highlight the application of Tasco as a potential feed additive to reduce pathogen shedding in rams without interfering with ruminal metabolism.

Investigation of ruminant xenobiotic metabolism in a modified rumen simulation system (RUSITEC).

The approving agencies for plant protection agents request xenobiotic metabolism and residue studies in rats, farm animals and plants (e.g. EU regulation 1107/2009) according to OECD guidelines. The specific intestinal physiology of ruminants might lead to specific residues, which should be investigated very carefully. Specific aspects of xenobiotic metabolism in ruminants may arise, which are investigated by performing additional in vivo studies. The aim of the present work is to asses a modified rumen simulation system (RUSITEC) for such studies in vitro. Rumen constituents from sheep were incubated over 8 days. Physiological parameters followed by monitoring the pH (6.70 ± 0.07), the redox potential (301 mV ± 30 mV), the microbial composition and determination of β-glucosidase activity. After anequilibration period of three to four days the fermenters were probed with 14C-labelled triazolederivatives, i.e.common metabolites of azole fungicides. Only triazole-alanine was cleaved to 1,2,4-triazole, while triazole-acetic acid and triazole-lactic acid remained stable up to 96 h. Moreover, glycosides are often determined as the main residues in the plants. This analysis showed, that the two glucosides octyl-β-D-glucopyranoside and polydatin were both rapidly cleaved in this rumen in vitro system. These data showed that the modified RUSITEC system is stable, viable and maintained metabolic capacity over a longer period (at least 8 days). This makes many animal experiments obsolete and lead to a significant contribution of the 3R (refine, reduce, replace). The modification of the RUSITEC system enables safe routine use for unlabeled but also for radioactive labelled compounds.

Evaluation of milk replacer supplemented with lysine and methionine in combination with glutamate and glutamine in dairy calves

ABSTRACTThis study aimed to evaluate performance, gut health and metabolic changes in dairy calves receiving milk replacer supplemented with lysine and methionine with 0.6% or 1% AminoGut (10% Glutamate and 10% Glutamine). Forty-five Holstein calves were blocked and distributed in the treatments: (1) Control: no supplementation; (2) Lys, Met, AminoGut 0.6%; (3) Lys, Met, AminoGut 1%. Animals were individually housed, with free access to water and concentrate. Milk replacer (6 L/d) was fed until the eighth week of life. Feed intake and faecal score were monitored daily. Calves were weighted and measured weekly. Blood samples were collected every other week to determine metabolites. Supplementation did not affect the performance nor the metabolism of calves. There was no effect of supplementation for faecal score. An age effect was observed for most of the variables, mainly as a response of starter intake and consequent shift from a pre to a functional ruminant metabolism. The supplementation of the milk replacer with lysine and methionine in association with 0.6% or 1% AminoGut had no effect on performance, gut health nor metabolism of dairy calves. More important than the fine adjustment of amino acid requirements is the adoption of practices to improve starter intake.

Ruminal acidosis: strategies for its control

Ruminal acidosis in ruminants is a metabolic disorder of gastrointestinal origin, which occurs in animals by high feed intake of cereal grains diets, which affect the performance. According to clinical manifestations it can be classified as: a) acute lactic acidosis in which there is prolonged exposure to ruminal pH≤5.0 that triggers a systemic acidosis, with clinical manifestations and changes in biochemical patterns, starting the first twelve hours of ruminal acidosis and it takes 48 to 120 hours to reestablish, b) subacute ruminal acidosis (SARA), has no clinical manifestations, rumen pH decreases in a range of 5.5 to 5.0 and is held for 111 to 180 minutes in 24 hours, this decrease causes an imbalance in the ruminal metabolism, as well as the fluid balance. Ruminal acidosis can be prevented by the addition of sodium bicarbonate in the ration, the use of zootechnic additives as Saccharomyces cereviseae and Megasphaera elsdenii as well as essential oils (cinnamaldehyde and eugenol). It is also important to consider the forage/concentrate ratio, the forage particle size, the NDF content of the ration, as well as the cereal’s rate of degradation in the rumen. The objective of this review was to address the ruminal acidosis pathophysiology, the effects this cause on animal welfare and control strategies to minimize the detrimental impact on animal production.

539 Evaluation ofBrassica carinatameal on ruminal metabolism and nutrient digestibility of beef cattle

Brassica carinatais a new oilseed crop in Florida with the potential of producing high-quality biodiesel for use as jet biofuel. A high-protein meal (∼40% CP) is obtained as a byproduct of oil extraction; however, this meal has not been tested as a potential protein supplement for cattle. A duplicated 4 × 4 Latin square design was used to determine the effects of supplementation withB. carinatameal on ruminal fermentation, digestibility, and blood profile in beef cattle consuming bahiagrass hay (Paspalum notatum), compared with frequently used protein supplements. Eight Angus crossbred steers (473 ± 119 kg initial BW) were randomly allocated to 8 pens, over 4 periods of 28 d each. Within period, steers were assigned to one of four treatments: 1.62 kg/d cottonseed meal (CSM), 2.15 kg/d dry distillers grains with solubles (DDGS), 1.39 kg/dB. carinatameal pellets (BCM), or 1.17 kg/d soybean meal (SBM), supplemented daily, on an isonitrogenous basis. Steers had ad libitum access to bahiagrass hay and water. Intake was measured using the GrowSafe system. Following a 14 d adaptation, feed and fecal samples were collected twice daily for 4 d to determine apparent total tract nutrient digestibility using iNDF as an internal marker. Blood and ruminal fluid samples were collected every 3 h, during a 24 h period, to analyze blood urea nitrogen (BUN) and glucose in plasma, as well as pH, NH3-N, and VFA concentrations in ruminal fluid. Data were analyzed using PROC MIXED of SAS with repeated measures. Model included the fixed effects of treatment, time, treatment × time, square, and period, and the random effects of steer (square) and steer (treatment). No effect of treatment (P>0.05) was observed for pH, NH3-N, or glucose concentration. An effect of treatment (P<0.01) was observed for BUN, with steers receiving SBM having greater concentrations. There was no effect of treatment (P>0.05) on total VFA concentrations. Steers consuming CSM had greatest acetate molar proportion, and greater acetate to propionate ratio when compared with DDGS and BCM. Steers consuming DDGS had greatest molar proportions of butyrate and greater molar proportions of propionate compared with SBM and CSM. There was no effect of treatment (P>0.05) on DMI or apparent total tract digestibility of DM, OM, CP, NDF, or ADF.Brassica carinataperformed similarly to commonly used protein supplements, excluding VFA profile, indicating its viability as a protein supplement for beef cattle.

Exploring the biological activity of condensed tannins and nutritional value of tree and shrub leaves from native species of the Argentinean Dry Chaco.

Tropical tree or shrub leaves are an important source of nutrients for ruminants and a potential source of biologically active compounds that may affect ruminal metabolism of nutrients. Therefore, eight woody species from the native flora of Argentinean Dry Chaco, rich in secondary compounds such as condensed tannins (CT), were assessed for their nutritional value, CT fractions and in vitro true digestibility of dry matter, as well as biological activity (BA). Differences among species were found in contents of total phenol, protein-precipitating phenols (PPP), bound proteins to PPP (BP) and BP/PPP (P < 0.0001). The BP/PPP ratio reveals differences among species in potential BA as indicated by protein precipitation. The major CT of each species were isolated and purified for use as a standard. Although Schinopsis balansae had the most (P ≤ 0.05) total CT (19.59% DM), Caesalpinia paraguariensis had greater (P ≤ 0.05) BA with the most PPP (530.21% dry matter). Larrea divaricata, at 0.97, followed by Acacia aroma, at 0.89, had CT with the highest (P ≤ 0.05) BP/PPP ratios, followed by Prosopis alba (0.59). There were differences in nutritive value and bioactivity among species. Those with the greatest CT were not necessarily those with the most BA. Caesalpinia paraguariensis, S. balansae and L. divaricata were the most promising species as native forage CT sources. Cercidiurm praecox (20.87% CP; 18.14% acid detergent fiber) and Prosopis nigra (19.00% CP; 27.96% acid detergent fiber) showed the best (P ≤ 0.05) nutritive values. According to their nutritive traits, these species might be complementary in grass-based ruminant diets. © 2017 Society of Chemical Industry.

Changes in the rumen bacterial microbiome of cattle exposed to ponderosa pine needles.

Consumption of ponderosa pine needles, as well as needles and bark from a number of other trees, can cause abortions in cattle. The abortifacient compounds in these trees are labdane resin acids, including isocupressic acid and agathic acid. Previous research has demonstrated that cattle conditioned to pine needles metabolize the labdane resin acids more quickly than naïve cattle. The results from that study indicated that changes had occurred in the rumen of conditioned cattle. Therefore, in this study, the changes that occurred in the rumen bacterial microflora of cattle during exposure to ponderosa pine needles were evaluated. Cattle were dosed with ground pine needles twice daily for 7 d. Rumen samples were collected on d 0, 3, 7, and 14 (7 d after treatment stopped) and ruminal bacterial microbiome analyses were performed. There were 372 different genera of bacteria identified in the rumen samples. Principal coordinate analysis indicated that there was a significant difference in the rumen bacterial composition between the time points. There were 18 genera that increased in abundance from d 0 to d 7. Twenty three genera decreased in abundance from d 0 to d 7. The results from this study demonstrated that exposure of cattle to pine needles caused a clear shift in the rumen microbiome composition. In general, this shift lasted less than 1 wk post exposure, which indicates that any prophylactic treatment to manipulate the ruminal metabolism of the abortifacient compounds in pine needles would need to be continuously administered to maintain the necessary microbial composition in the rumen.

&lt;i&gt;In situ &lt;/i&gt;ruminal degradability of protein feeds with distinct physical forms: a meta-analysis

In ruminant livestock, rumen undegradable protein (RUP) derived from the diet and microbial protein synthesized in the rumen are essential for animal survival, maintenance, growth, production, and reproduction. RUP is influenced by diet composition, physical form, and ruminal metabolism. Here, we aimed to evaluate the ruminal degradability of protein feeds with different physical forms (meal versus grain) through a meta-analysis study. A database, composed of 45 treatments from 12 studies carried out in Brazil, was evaluated to compare the degradability of soybean, sunflower, canola, and flaxseed grains with the meal forms of soybean, peanut, sunflower, cottonseed, and corn gluten. The degradation parameters of dry matter did not differ significantly between meals and grains. However, the effective degradability of crude protein at a passage rate of 2% per hour was higher in meals than in grains. Overall, it was concluded that meal protein might be more degradable in the rumen of animals on an energy intake lower than the maintenance. Keywords : Concentrated feed, metabolism, passage rate, processing, ruminants

Effects of the interaction of forage and supplement type on digestibility and ruminal fermentation in beef cattle.

The objectives of this research were to test interactions of supplement type, liquid versus dry, and forage type, hay versus corn stover, on digestibility and ruminal metabolism of beef cattle. Ruminally fistulated steers were fed in a replicated 4 × 4 Latin square with a 2 × 2 factorial arrangement of treatments: 1) hay with liquid supplement, 2) hay with dry supplement, 3) corn stover with liquid supplement, and 4) corn stover with dry supplement. The liquid supplement was molasses and glycerin based (23.3% CP and 1.63 Mcal/kg NEm) whereas the dry supplement was ground corn based (16.8% CP and 1.81 Mcal/kg NEm). Each period, steers were adapted to diets for 14 d and samples were collected for 8 d. In situ disappearance was determined by a 24-h incubation of Dacron bags, containing soybean hulls, in the rumen. There were no interactions ( ≥ 0.25) of supplement and forage type on DMI, apparent total tract digestibility, or ruminal pH. There was a tendency ( = 0.08) for a forage × supplement type interaction for in situ NDF disappearance (ISNDFD). There were no differences in ISNDFD in steers fed hay, but liquid supplement increased ISNDFD in steers fed corn stover. There were no main effects ( ≥ 0.12) of supplement type on DMI, apparent total tract or in situ digestibility, or ruminal pH. There was a supplement × hour interaction ( = 0.04) for acetate concentrations. Although no effect occurred at 0 h after feeding, at 3 and 6 h after feeding, acetate concentrations were reduced in steers fed liquid supplements when compared with those fed dry supplements. In addition, there was a supplement × hour ( = 0.02) interaction for butyrate concentrations, where at all time points, butyrate concentrations increased ( ≤ 0.01) in steers fed liquid supplements when compared with those fed dry supplements. Steers fed hay had increased DMI ( < 0.01) and apparent total tract NDF digestibility ( = 0.07) when compared with steers fed corn stover, regardless of supplement type. At 0, 1.5, and 18 h after feeding, ruminal pH was greater ( ≤ 0.01) in cattle consuming corn stover when compared with those fed hay, regardless of supplement type. However, steers fed hay had increased ( < 0.01) concentrations of acetate and total VFA compared with steers fed corn stover, regardless of supplement. Feeding liquid supplement increased ISNDFD when steers were fed corn stover; however, these changes were not associated with differences in total tract digestibility. Regardless of forage type fed, the liquid supplement increased ruminal butyrate concentrations.

Dietary n-6:n-3 Fatty Acid Ratios Alter Rumen Fermentation Parameters and Microbial Populations in Goats.

Revealing the ruminal fermentation patterns and microbial populations as affected by dietary n-6:n-3 PUFA ratio would be useful for further clarifying the role of the rumen in the lipid metabolism of ruminants. The objective of the present study was to investigate the effects of dietary n-6:n-3 PUFA ratios on fermentation characteristics, fatty acid (FA) profiles, and microbial populations in the rumen of goats. A total of twenty-one goats were randomly assigned to three dietary treatments with different n-6:n-3 PUFA ratios of 2.27:1 (low ratio, LR), 5.01:1 (medium ratio, MR), and 10.38:1 (high ratio, HR). After 100 days of feeding, all goats were slaughtered. Dietary n-6:n-3 PUFA ratios had no effect (P > 0.05) on rumen pH and NH3N concentration. Goats fed HR diet had lower (P < 0.05) propionate and total volatile fatty acids and higher (P < 0.05) butyrate compared with those fed the MR and LR diets. The proportion of C18:0 decreased (P < 0.05) as dietary n-6:n-3 PUFA ratios increased. The proportions of C18:1 trans-11, C18:2n-6, cis-9 trans-11 CLA, and C20:4n-6 were greater in the HR goats compared with the MR and LR goats. Lowering dietary n-6:n-3 PUFA ratios enhanced (P < 0.05) the proportion of C18:3n-3 and total n-3 PUFA in the rumen fluid of goats. The populations of R. albus and R. flavefaciens decreased (P < 0.05) as the n-6:n-3 PUFA ratios increased in diet. Diet had no effect (P > 0.05) on the ruminal populations of F. succinogenes, total bacteria, methanogens, total protozoa, Entiodinium, and Holotrich. The population of B. fibrisolvens was lower (P < 0.05) in the LR goats compared with the MR and HR goats. It was concluded that HR would increase the concentration of cis-9 trans-11 CLA and C18:1 trans-11 in the rumen. However, LR whould decrease the B. fibrisolvens population, which is involved in the BH process in the rumen. Further research is needed to evaluate the potential role and contribution of rumen microbiome in the metabolism of FA in the rumen.