Molar Proportions Of Isovalerate Research Articles

Effect of feeding calcium gluconate embedded in a hydrogenated fat matrix on performance, gastrointestinal fermentation, ruminal morphology, carcass merit, and meat quality for finishing beef heifers

Twenty-one beef heifers were used in a randomized complete block design lasting 206 ± 8 day (mean ± SD) to evaluate dry matter intake (DMI), growth, and gastrointestinal tract and carcass characteristics with increasing dose of dietary hydrogenated fat-embedded calcium gluconate (HFCG). Dietary treatments included HFCG included at: 0.0% (CON), 0.09% (CG09), or 0.18% (CG18) DM. Heifers were fed individually and fecal samples were collected on d 171 and 192. Gastrointestinal tissue, digesta, carcass merit, and meat quality and sensory characteristics were assessed after slaughter. Data were analyzed to determine the linear and quadratic effects of HFCG dose. DMI, average daily gain (ADG), and G:F were not affected ( P ≥ 0.08) by dose of HFCG. Gastrointestinal fermentation was minimally affected, while quadratic responses ( P = 0.03 and 0.01, respectively) were observed for jejunal digesta pH and the molar proportion of isovalerate in colonic digesta where both increased and then decreased as HFCG dose increased. Carcass ( P ≥ 0.30), meat quality ( P ≥ 0.06), and sensory characteristics ( P ≥ 0.21) were not affected by dose of HFCG. We conclude that feeding HFCG to finishing beef heifers did not affect DMI, growth, gastrointestinal fermentation parameters, or carcass merit, meat quality, and palatability.

Effects of yeast culture supplementation on lactation performance and rumen fermentation profile and microbial abundance in mid-lactation Holstein dairy cows

The continuous trend for a narrowing margin between feed cost and milk prices across dairy farms in the United States highlights the need to improve and maintain feed efficiency. Yeast culture products are alternative supplements that have been evaluated in terms of milk performance and feed efficiency; however, less is known about their potential effects on altering rumen microbial populations and consequently rumen fermentation. Therefore, the objective of this study was to evaluate the effect of yeast culture supplementation on lactation performance, rumen fermentation profile, and abundance of major species of ruminal bacteria in lactating dairy cows. Forty mid-lactation Holstein dairy cows (121 ± 43 days in milk; mean ± standard deviation; 32 multiparous and 8 primiparous) were used in a randomized complete block design with a 7-d adaptation period followed by a 60-d treatment period. Cows were blocked by parity, days in milk, and previous lactation milk yield and assigned to a basal total mixed ration (TMR; 1.6 Mcal/kg of dry matter, 14.6% crude protein, 21.5% starch, and 38.4% neutral detergent fiber) plus 114 g/d of ground corn (CON; n = 20) or basal TMR plus 100 g/d of ground corn and 14 g/d of yeast culture (YC; n = 20; Culture Classic HD, Cellerate Yeast Solutions, Phibro Animal Health Corp.). Treatments were top-dressed over the TMR once a day. Cows were individually fed 1 × /d throughout the trial. Blood and rumen fluid samples were collected in a subset of cows (n = 10/treatment) at 0, 30, and 60 d of the treatment period. Rumen fluid sampled via esophageal tubing was analyzed for ammonia-N, volatile fatty acids (VFA), and ruminal bacteria populations via quantitative PCR amplification of 16S ribosomal DNA genes. Milk yield was not affected by treatment effects. Energy balance was lower in YC cows than CON, which was partially explain by the trend for lower dry matter intake as % body weight in YC cows than CON. Cows fed YC had greater overall ruminal pH and greater total VFA (mM) at 60 d of treatment period. There was a contrasting greater molar proportion of isovalerate and lower acetate proportion in YC-fed cows compared with CON cows. Although the ruminal abundance of specific fiber-digesting bacteria, including Eubacterium ruminantium and Ruminococcus flavefaciens, was increased in YC cows, others such as Fibrobacter succinogenes were decreased. The abundance of amylolytic bacteria such as Ruminobacter amylophilus and Succinimonas amylolytica were decreased in YC cows than CON. Our results indicate that the yeast culture supplementation seems to promote some specific fiber-digesting bacteria while decreasing amylolytic bacteria, which might have partially promoted more neutral rumen pH, greater total VFA, and isovalerate.

Characterization of dairy cow rumen bacterial and archaeal communities associated with grass silage and maize silage based diets.

The objective of the present study was to characterize the rumen bacterial and archaeal communities in dairy cows fed different ratios of maize silage (MS) and grass silage (GS), and place the findings in the context of ruminal fermentation as well as previously reported methane (CH4) emissions. Rumen fluid from 12 rumen cannulated dairy cows was collected after 10 and 17 days of feeding one of four diets, all of which had the same roughage to concentrate ratio of 80:20 based on dry matter (DM). Roughage in the four diets (GS100, GS0, GS67, GS33) consisted of either 1000 g/kg DM GS (GS100), 1000 g/kg DM MS (GS0), or a mixture of both silages in different proportions [667 g/kg DM GS and 333 g/kg DM MS (GS67); 333 g/kg DM GS and 677 g/kg DM MS (GS33)]. Total volatile fatty acid (VFA) concentrations and the molar proportions of the ruminal VFA were not affected by diet. Only the molar proportion of isovalerate was affected by time, being lower on day 17 than on day 10. Bacterial and archaeal concentrations were not affected by diet but increased from day 10 to day 17. The bacterial community composition was affected by diet, time and diet × time, whereas the archaeal community composition was only affected by diet. Several bacterial and archaeal genus level groups were associated with diet, but not with time. Analysis indicated the increased use of hydrogen by succinate and lactate producing bacteria is likely to at least partially explain the previously reported lower CH4 emissions from MS fed dairy cows. Furthermore, time had a significant effect on both bacterial and archaeal concentrations, and also bacterial community composition. This indicates that the rumen microbiota had not stabilized after 10 days of feeding the experimental diets.

Influence of increasing doses of a yeast hydrolyzate obtained from sugarcane processing on in vitro rumen fermentation of two different diets and bacterial diversity in batch cultures and Rusitec fermenters

Live yeast cultures and yeast hydrolyzates can be used as rumen fermentation modifiers, but their effects and mode of action are different. Whereas the effects of live yeast cultures on rumen fermentation are well documented, yeast hydrolyzates have received much less attention. The influence of a yeast hydrolyzate from Saccharomyces cerevisiae, obtained after ethanol production from sugarcane (YHS), on in vitro rumen fermentation was investigated using both batch cultures and Rusitec fermenters inoculated with ruminal fluid from sheep. Batch cultures (300mg dry matter (DM)) with two mixed diets (AHC, 0.5:0.5 alfalfa hay:concentrate; BSC, 0.15:0.85 barley straw:concentrate) as substrate were supplemented with increasing doses of YHS (0, 3.3, 6.7, 10.0 and 13.3ml/l) and incubated for 16.5h at 39°C. Supplementation of increasing amounts of YHS to AHC-cultures increased (P<0.05) linearly total volatile fatty acid (VFA) production and butyrate molar proportion, and decreased (P<0.001) acetate proportion and acetate:propionate ratio. In contrast, only subtle effects of YHS on NH3-N concentrations and molar proportions of isovalerate and caproate were observed for the BSC diet. Longer-term effects of YHS supplementation on rumen fermentation of AHC diet were investigated using four Rusitec fermenters in a cross-over experimental design with two 14-day incubation periods. Fermenters were given daily 30g of diet DM, and in each period half of them were supplemented daily with 5ml of YHS (10.0ml/l) Supplementing with YHS did not affect (P>0.05) total VFA production, lactate concentrations, DM and aNDFom disappearance or enzymatic activities (amylase, xylanase and carboxymethylcellulase). Compared with the unsupplemented fermenters, YHS treatment increased (P<0.001) NH3-N concentrations and molar proportions of propionate and butyrate at the expense of acetate, and decreased (P<0.001) acetate:propionate ratio. In addition, YHS supplementation tended (P<0.07) to reduce CH4/total VFA ratio and to increase microbial growth in the liquid phase of the fermenters. The automated ribosomal intergenic spacer analysis (ARISA) of samples taken on days 3, 8 and 14 of incubation from solid and liquid content of fermenters revealed that YHS supplementation increased (P<0.02) bacterial diversity in the liquid phase and tended to increase (P<0.08) it in the solid phase. The results indicate that YHS at a dose of 10ml/l may be a useful dietary additive for ruminants, because it promoted a shift in fermentation toward propionate production, reduced the CH4/total VFA ratio and increased microbial growth with a 50:50 alfalfa hay:concentrate diet.

Effects of replacing soybean meal with canola meal differing in rumen-undegradable protein content on ruminal fermentation and gas production kinetics using 2 in vitro systems

Previous research indicated that there were significant differences in rumen-undegradable protein (RUP) among canola meals (CM), which could influence the nutritional value of CM. The objectives of this study were to (1) evaluate the effects of feeding CM with different RUP contents on ruminal fermentation, nutrient digestion, and microbial growth using a dual-flow continuous culture system (experiment 1) and (2) evaluate ruminal gas production kinetics, in vitro organic matter (OM) digestibility, and methane (CH4) production of soybean meal (SBM) and CM with low or high RUP in the diet or as a sole ingredient using a gas production system (experiments 2 and 3). In experiment 1, diets were randomly assigned to 6 fermentors in a replicated 3 × 3 Latin square. The only ingredient that differed among diets was the protein supplement. The treatments were (1) solvent-extracted SBM, (2) low-RUP solvent-extracted CM (38% RUP as a percentage of crude protein), and (3) high-RUP solvent-extracted CM (50% RUP). Diets were prepared as 3 concentrate mixtures that were combined with 25% orchardgrass hay and 15% wheat straw (dry matter basis). Experiments 2 and 3 had the same design with 24 bottles incubated 3 times for 48 h each. During the 48-h incubation, the cumulative pressure was recorded to determine gas production kinetics, in vitro OM digestibility, and CH4 production. In experiment 1, N flow (g/d), efficiency of N use, efficiency of bacterial N synthesis, total volatile fatty acids (mM), and molar proportion of acetate, propionate, and isobutyrate were not affected by treatments. There were tendencies for a decrease in ruminal NH3-N and an increase in molar proportion of butyrate for the SBM diet compared with both CM diets. The molar proportion of valerate was greater in both CM diets, whereas the molar proportion of isovalerate and total branched-chain volatile fatty acids was lower for the CM diets compared with the SBM diet. In experiments 2 and 3, the SBM diet had a greater gas pool size than both CM diets. The SBM diet increased in vitro OM digestibility; however, it also tended to increase CH4 production (mM and g/kg of DM) compared with both CM diets. Based on the results of this study, CM with RUP varying from 38 to 50% of crude protein does not affect ruminal fermentation, nutrient digestion, and microbial growth when CM is included at up to 34% of the diet.

Effects of Momordica charantia polysaccharide on in vitro ruminal fermentation and cellulolytic bacteria

Four levels of Momordica charantia polysaccharide (MCP) supplements (0, 0.1, 0.3, 0.6 mg/ml) were designed to investigate the effects of MCP on ruminal fermentation and cellulolytic bacteria in vitro. The pH, ammonia-N (NH3-N) and volatile fatty acids (VFA) were measured at 6, 24, 48 h, whilst the cellulolytic bacteria population was determined at 6 and 24 h. The 0.6 mg/ml MCP inclusion decreased the theoretical maximum of gas production and the half-life. The NH3-N concentration was decreased by MCP at all doses at 24 h. The MCP inclusion increased the concentration of total VFA at 24 and 48 h and the acetate to propionate ratio, the molar proportion of isovalerate at 6 h, while decreased that of isobutyrate at 24 h and that of isovalerate, valerate at 24 and 48 h, respectively. The relative abundances of Ruminococcus albus and Ruminococcus flavefaciens were decreased at 6 h, while that of Butyrivibrio fibrisolvens was increased at all times of incubation and that of Fibrobacter succinogenes reached the greatest value at 0.6 mg/ml MCP supplementation at 24 h. This study demonstrated that the MCP had the ability to enhance the total VFA production, modulate the rumen fermentation pathway and influence the number of cellulolytic bacteria population.

Effects of Branched-chain Amino Acids on In vitro Ruminal Fermentation of Wheat Straw.

This study investigates the effects of three branched-chain amino acids (BCAA; valine, leucine, and isoleucine) on the in vitro ruminal fermentation of wheat straw using batch cultures of mixed ruminal microorganisms. BCAA were added to the buffered ruminal fluid at a concentration of 0, 2, 4, 7, or 10 mmol/L. After 72 h of anaerobic incubation, pH, volatile fatty acids (VFA), and ammonia nitrogen (NH3-N) in the ruminal fluid were determined. Dry matter (DM) and neutral detergent fiber (NDF) degradability were calculated after determining the DM and NDF in the original material and in the residue after incubation. The addition of valine, leucine, or isoleucine increased the total VFA yields (p≤0.001). However, the total VFA yields did not increase with the increase of BCAA supplement level. Total branched-chain VFA yields linearly increased as the supplemental amount of BCAA increased (p<0.001). The molar proportions of acetate and propionate decreased, whereas that of butyrate increased with the addition of valine and isoleucine (p<0.05). Moreover, the proportions of propionate and butyrate decreased (p<0.01) with the addition of leucine. Meanwhile, the molar proportions of isobutyrate were increased and linearly decreased (p<0.001) by valine and leucine, respectively. The addition of leucine or isoleucine resulted in a linear (p<0.001) increase in the molar proportions of isovalerate. The degradability of NDF achieved the maximum when valine or isoleucine was added at 2 mmol/L. The results suggest that low concentrations of BCAA (2 mmol/L) allow more efficient regulation of ruminal fermentation in vitro, as indicated by higher VFA yield and NDF degradability. Therefore, the optimum initial dose of BCAA for in vitro ruminal fermentation is 2 mmol/L.

Altering Soluble and Potentially Rumen Degradable Protein for Prepubertal Holstein Heifers

Four prepubertal Holstein heifers, average age 184±2.1 d and 169.1±15.8kg of body weight, fitted with rumen cannulae were used to evaluate effects of altering the soluble CP and potentially rumen degradable protein fractions of diets containing 16% CP and 71.5% TDN. Parameters studied included rumen ammonia, volatile fatty acid production, N balance, total tract apparent digestibility, and urinary excretion of purine derivatives in a 4×4 Latin square design with a 2×2 factorial arrangement of treatments. Heifers were fed treatment rations containing 62.1±0.8g CP /Mcal ME at 2.0% BW with altered soluble CP fractions (AB1) (33.6 or 40.6% of CP) and potentially rumen degradable protein fractions (B2 B3) (20.9 or 28.2% of CP). Increased intake of AB1 increased rumen ammonia and decreased total volatile fatty acid concentrations with molar proportions of isovalerate and isobutyrate decreased. Increased intake of B2B3 tended to increase volatile fatty acid concentrations, increased molar proportions of propionate, and decreased the acetate to propionate ratio. Nitrogen utilization was not affected by increased intake of AB1 or B2B3, although increased intake of AB1 tended to increase urine urea excretion. Increasing solubility (40.6 versus 33.6% AB1) of dietary CP when feeding a 16% CP and 71.5% TDN ration, decreased total volatile fatty acid concentrations and molar proportions of isovalerate and isobutyrate. Feeding 62.1±0.8g CP/Mcal ME with increased potentially rumen degradable protein (28.2 versus 20.9% B2B3) at 2.0% BW affected rumen fermentation but did not affect DM digestibility or N utilization.

Effect of either once or twice daily concentrate supplementation of wheat straw on voluntary intake and digestion in sheep

Eighteen mature Merino ewes were used to study the effect of either once or twice daily concentrate supplementation of wheat straw on voluntary intake and diet digestibility. Diets consisted of wheat straw, fed as the only feed (S0) or supplemented with 0.450 kg of concentrate per day (850 g cracked barley grain, 120 g soya-bean meal and 30 g vitamin–mineral supplement per kg of concentrate) given either in a meal (S1) or in two equal meals (S2). Concentrate supplementation tended ( P<0.10) to reduce the daily intake of wheat straw (mean values 13.8, 10.4 and 11.3 g dry matter (DM) per kg live weight for S0, S1 and S2 diets, respectively), but total dry matter (DM) intake and apparent DM digestibility were increased ( P<0.01). Apparent digestibility of the diet and digestible organic matter (OM) intake were unaffected ( P>0.05) by the frequency of concentrate feeding. Rumen fermentation were studied using three rumen-cannulated Merino sheep in a 3×3 Latin square design. Concentrate supplementation decreased ( P<0.01) ruminal pH (mean values of 6.79, 6.03 and 5.98 for S0, S1 and S2, respectively) and increased ( P<0.05) ammonia–N concentration (40.0, 132.1 and 168.3 mg/l for S0, S1 and S2, respectively). Total volatile fatty acids (VFA) concentrations and molar proportions of butyrate, isovalerate and valerate were increased by concentrate feeding ( P<0.001, 0.05, 0.001 and 0.05, respectively), whereas the proportions of acetate and isobutyrate were decreased ( P<0.05). Increasing the concentrate feeding frequency to twice daily did not affect ( P>0.05) ruminal pH, ammonia–N or VFA concentrations, but increased ( P<0.01) the molar proportion of isovalerate (0.832 and 1.135% for S1 and S2, respectively). Concentrate supplementation decreased ( P<0.05) the in situ degradation rate of both wheat straw neutral-detergent fibre and concentrate crude protein (CP), but the pattern of concentrate feeding did not affect ( P>0.05) the in situ degradation of either wheat straw or concentrate.

Effect of Casein Infusion in the Rumen, Duodenum or Both Sites on Factors Affecting Forage Intake and Performance of Dairy Cows Fed Red Clover-Grass Silage

Four lactating dairy cows were used in a balanced 4 × 4 Latin square design to examine the effects of casein infusion in the rumen, duodenum, or both on the intake of red clover-grass silage, chewing behavior, diet digestion, microbial protein synthesis, rumen fermentation, digestion, and passage kinetics, milk production, and milk composition. Duodenal infusion increased eating time, silage intake, rumen neutral detergent fiber pool, yields of milk, protein, and lactose, and concentration of milk protein, and tended to decrease that of milk fat. Ruminal infusion tended to decrease eating time, and increased significantly microbial protein synthesis, rumen ammonia-N concentration, molar proportions of isovalerate and valerate, digestion rate of digestible neutral detergent fiber, passage rate of indigestible neutral detergent fiber, and milk urea content, and decreased rumen neutral detergent fiber pool. Silage intake, and yields of milk, protein, and lactose were highest when casein was simultaneously infused in both sites.

Effects of a bacterial inoculant and propionic acid on preservation of high-moisture ear corn, and on rumen fermentation, digestion and growth performance of beef cattle

Studies of aerobic stability, digestion and growth performance were conducted with steers to determine the mode of action of a bacterial inoculant in altering the feeding value of ensiled high-moisture ear corn (HMEC); a comparison was made with propionic acid (PA) treated HMEC (10 g kg–1 fresh matter). The inoculant consisted of Lactobacillus plantarumand Enterococcus faecium, and was applied as an aqueous solution to provide 104 colony-forming units (cfu) per gram of HMEC. Inoculation of HMEC was not as effective as PA in improving aerobic stability, as assessed by changes in populations of yeasts and moulds. However, steers fed inoculated HMEC gained 11% more weight (P &lt; 0.05) than animals fed untreated HMEC, and 9% more (P &lt; 0.10) than those fed PA-treated material. There were no effects of treatment on food intake or digestion of organic matter (OM). At 4 h after feeding, rumen pH and molar proportions of isovalerate were greater (P &lt; 0.05) with inoculated than untreated or PA-treated HMEC. Treatment differences in aerobic stability of HMEC did not account for the responses in growth performance. It appears that improvements in growth rate of beef cattle fed inoculated HMEC may be related to pH and/or the production of iso-acids in the rumen. Key words: Beef cattle, high-moisture ear corn, inoculant, propionic acid, growth rate, rumen fermentation

Nutrient Intake and Digestibility of Cotton Gin Trash Treated with Hypochlorite Oxidant or Extruded

Bernard, J.K., Woldeghebriel, A. and Mueller, T.C. 2001. Nutrient intake and digestibility of cotton gin trash treated with hypochlorite oxidant or extruded. J. Appl. Anim. Res., 19: 165–176. To determine the effect of hypochlorite oxidant and extrusion on nutrient intake and digestibility of gin trash (GT) and compare GT with pelleted cottonseed hull (PCSH), two trials were conducted. Treatments included PCSH, untreated (CONT), predigested with a hypochlorite oxidant (PD), extruded (EXT) and predigested and extruded (P&E) byproduct. Five Holstein heifers were used in a 5 × 5 Latin square design and fed diets containing 25% GT or PCSH. Dry matter (DM) intake of heifers was not different among treatments but intake of diets containing GT was 17% lower than PCSH. Apparent digestibility of DM, OM, and NDF was similar for all treatments; however, ADF digestibility was lowest for PCSH compared to CONT, PD and P&E. Ruminal NH3-N concentration was highest for P&E compared to PCSH, CONT and PD. Extrusion decreased molar proportions of acetate (A) and increased propionate (P) resulting in lower A:P ratios. Molar proportions of butyrate was greatest for CONT and P&E and molar proportions of isovalerate was greatest for PCSII and PD. Concentrations of plasma urea-N (PUN) and glucose were not different among treatments. In situ digestibility of DM and NDF was greatest for GT compared to PCSH. Treatment of GT with the mixed oxidant or extruding the GT did not improve DM or NDF digestibility at 48 and 96 h compared to CONT. All GT treatments were digested equally at 192h. Extrusion improved bulk density of GT by 63% but did not improve DM intake or apparent digestibility. Extruding the material treated with the mixed oxidant in the current study appeared to eliminate any potential increase in apparent digestibility compared with the PD byproduct. This may in part be attributed to the potential loss of solublized components resulting in increased concentration of less digestible fraction in the remaining material.

The effects of intraruminal infusions of sucrose and xylose on nitrogen and fibre digestion in the rumen and intestines of cattle receiving diets of grass silage and barley

Two male cattle (live weight 240 kg) fitted with rumen and simple T-piece duodenal cannulas were given a basal diet of 12 kg of silage (227 g/kg DM, 25.7 g N/kg DM), 1 kg of rolled barley and 100 g of mineral mixture. In addition to the basal diet, 0, 450 or 900 g/d of either sucrose or xylose was continuously infused intraruminally. The amount of organic matter (OM) entering the duodenum (P &lt; 0.001) and excreted in the faeces (P &lt; 0.01) was linearly increased with the increased sugar infusion. The proportion of digestible OM apparently digested in the rumen averaged 0.694, and did not differ (P &gt; 0.05) with the level or type of sugar. Rumen ammonia concentration and molar proportions of isovalerate were decreased (P &lt; 0.001) with increased sugar level. The decrease in the ammonia concentration was slightly less (P &lt; 0.05) with xylose than with sucrose. Molar proportions of acetate, propionate and butyrate were not affected by the sugar level but sucrose produced a lower (P &lt; 0.05) proportion of acetate and higher (P &lt; 0.01) proportion of butyrate than did xylose. There was a net loss of N (11.6g/d) between the mouth and duodenum when the basal diet was consumed alone but a net gain (21.6 g/d) with the high level of sugar infusion. Microbial N flow at the duodenum, measured on the basis of RNA purine bases, increased linearly (P 0.05) for sugar levels of 0, 450 and 900 g/d, respectively. The amount of microbial N produced was closely related to rumen ammonia concentration (r—0.86; P &lt; 0.001) and outflow of water at the duodenum (r 0.83; P