In Vitro Dry Matter Disappearance Research Articles

84 Evaluating the effects of hind gut acidosis in sheep on rumen fermentation ex vivo

Abstract The objective was to determine the effect of hindgut acidosis in sheep on rumen fermentation ex vivo. Eleven ruminally and cecally cannulated ewes [body weight (BW) = 49 ± 4 kg] were assigned to one of two treatments: a constant infusion of deionized water (CON; 26 mL/kg BW per 24 h) or starch solution (STA; 3 g wheat starch/kg BW per 24 h) in the cecum to induce hindgut acidosis. Rumen fluid was collected from each ewe on the d before and four d after the start of cecal infusion for an ex vivo fermentation. There were four flasks for each ewe with two flasks per substrate. The two substrates were forage-based (FB; 40% grass hay pellet, 35% whole shell corn, 15% dried distiller’s grain, and 10% alfalfa cubes) and concentrate-based (CB; 75% whole shell corn, 15% dried distiller’s grain, and 10% alfalfa cubes). Flasks contained 2.5 grams of substrate and 150 mL of inoculum (2:1 ratio of McDougall’s buffer and rumen fluid). Four sealed ANKOM F57 bags were filled with 0.25g DM of substrate and placed into flasks to determine in vitro dry matter disappearance (IVDMD). The flasks were incubated at 39°C for 24 h, with sample aliquots collected at h 0, 8, and 24 to determine pH, volatile fatty acids (VFA), and ammonia. Data were analyzed using the MIXED procedure of SAS 9.4. For all response variables, values from the run before cecal infusion initiation were included in the model as a covariate. Ammonia, pH, and VFA were analyzed with the effects of treatment, time, and their interaction. For the CB substrate, there was no effect (P = 0.90) of cecal infusion on ammonia concentration; however, there was a time effect (P = 0.01) with h 24 having a greater ammonia concentration than h 8. For the FB substrate, there was a tendency for STA to have lesser (P = 0.10) ammonia than CON. There was no effect (P ≥ 0.78) of cecal infusion treatment on pH for both substrates; however, there was a time effect (P = 0.01) with pH decreasing over time. In both substrates, there were no effects (P ≥ 0.23) of cecal infusion treatment on IVDMD, VFA concentration, acetate, or propionate molar concentration. However, butyrate molar concentration tended to be less (P = 0.07) for STA ewes for the CB substrate. No treatment differences were observed in butyrate for the FB substrate (P = 0.35). Results indicate that induced hindgut acidosis in sheep did not affect rumen fermentation ex vivo.

87 Evaluating the effects of an amino acid-formulated diet on ruminal fermentation in vitro

Abstract The objective was to determine the effect of an amino acid-formulated diet on ruminal fermentation in vitro. While most amino acid-formulated diets focus on improving the amino acid composition of rumen undegradable protein, additional benefits to microbial fermentation within the rumen are unknown. The experiment was a completely randomized design with a factorial treatment arrangement (2 donor diets and 2 substrates). Four ruminally cannulated steers were fed one of two donor diets: control (CON; 55% dry rolled corn, 20% corn silage, 15% dry distiller’s grain, and 10% supplement) and amino acid-formulated (AAF; 51% dry rolled corn, 15% corn silage, 14% dry distillers grain, 10% heat-treated soybean meal, and 10% supplement). After a 30-d diet adaptation period, rumen fluid was collected and pooled by donor diet for the in vitro fermentation. Additionally, two different substrates were used to represent each donor diet. Flasks contained 2.5 g dry matter (DM) of substrate and 150 mL of rumen fluid mixture (2 McDougall’s buffer:1 rumen fluid). Treatments were evaluated in triplicate flasks in two replicated runs for a total of six observations per treatment. Four sealed Ankom F57 bags were filled with 0.25 g DM of substrate each to facilitate measuring in vitro DM disappearance (IVDMD). Flasks were incubated at 39°C with sample aliquots collected at h 0, 4, 8, 12, and 24 to determine pH, ammonia, and volatile fatty acids (VFA). Data were analyzed using the MIXED procedure of SAS 9.4 with a repeated measures analysis. Ammonia, pH, and VFA were analyzed with effects of donor diet, substrate, time, and all interactions. A treatment by hour interaction was detected (P < 0.01) for pH; fluid from steers fed CON was greater than AAF at h 4, 8, 12, and 24. A treatment by hour interaction was also detected (P = 0.02) for ammonia; fluid from steers fed CON was greater than AAF at h 24, but was not different at other time points. Total VFA was affected by hour (P < 0.01) as it increased over time, but substrate did not have an effect (P = 0.21). A treatment by hour interaction (P = 0.06) tended to be observed for molar proportions of acetate as AAF and CON were similar at h 0 but AAF was increasing greater than CON over time. A treatment by hour interaction was observed (P = 0.01) for molar proportions of propionate; at h 4 at 8, CON was greater than AAF. No effect (P ≥ 0.32) of donor diet, substrate or their interaction were observed on IVDMD. Overall, an amino acid-formulated diet for cannulated steers did impact ruminal fermentation in vitro, mostly altering molar proportions of volatile fatty acids and ammonia release from protein degradation.

Gas Kinetics, Rumen Characteristics, and In Vitro Degradability of Varied Levels of Dried and Fresh Cassava Leaf Top Fermented with Cassava Pulp

The purpose of this study was to determine the impact of different levels of dried cassava leaf top (DCT) and fresh cassava leaf top (FCT) fermented with cassava pulp (CS) on the nutritional value of silage, gas kinetics, rumen characteristics, and in vitro degradability. Dietary treatments were administered using a completely randomized design (CRD) with eight treatments and three replicate runs. The eight treatments were as follows: 1) CS fermented no additive (nA), 2) CS fermented with additives ( Saccharomyces cerevisiae , urea, molasses, and sugar) (CSA), 3) 95% CSA fermented with 5% DCT (5DCT), 4) 90% CSA fermented with 10% DCT (10DCT), 5) 85% CSA fermented with 15% DCT (15DCT), 6) 95% CSA fermented with 5% FCT (5FCT), 7) 90% CSA fermented with 10% FCT (10FCT), 8) 85% CSA fermented with 15% FCT (15FCT), respectively. After 21 days of fermentation, samples of the silages were taken for chemical analysis and utilized to examine the in vitro gas production and degradability. The results show that fermented CS with DCT at 5% to 10% DM had the highest increase in CP when compared to nA or CSA (p<0.05). In vitro dry matter disappearance (IVDMD) was significantly higher in CS fermented with 5% to 10% DCT (p<0.01), whereas CS fermented with FCT levels demonstrated lower IVDMD than the control group (p<0.01). The gas potential extent of gas production (p) and gas production from the insoluble fraction (b) did not differ significantly across treatments (p>0.05). However, the gas production from the immediately soluble fraction (a) was maximum when CS was fermented with 15DCT (p<0.05). Different treatments significantly affected the pH of the fermentation solution with the addition of 10DCT and 15DCT for 12 and 24 hours of incubation, respectively (p<0.01). After 12 hours of incubation, the population of protozoa was lowest when 5DCT and 10DCT were evaluated (p<0.01). In conclusion, CS fermented with DCT at a concentration of 5% to 10% can increase crude protein content, in vitro dry matter disappearance (IVDMD), and gas production from the immediately soluble fraction while decreasing the protozoa population.

Effect of Dietary Rumen-Degradable Starch to Rumen-Degradable Protein Ratio on In Vitro Rumen Fermentation Characteristics and Microbial Protein Synthesis.

Simple SummarySynchronizing the energy and nitrogen supply in the rumen was reported to improve feed efficiency; however, synchronization indicators were rarely reported. The present study was conducted using a batch culture technique to evaluate the optimal rumen-degradable starch (RDS) and rumen-degradable protein (RDP) ratio (SPR) for synchronizing the energy and nitrogen supply for dairy cows. The in vitro disappearance of dry matter and neutral and acid detergent fiber, gas production and microbial crude protein synthesis quadratically increased with increasing the SPR and peaked at 2.3. Although an in vivo study could be further needed, our results provided an optimal SPR range for dairy cows to synchronize the energy and nitrogen supply.The objective of this study was to investigate the effects of dietary rumen-degradable starch (RDS, g/kg of DM) to rumen-degradable protein (RDP, g/kg of DM) ratios (SPR) on in vitro rumen fermentation characteristics and microbial protein synthesis (MCPS). Treatments were eight diets with SPR of 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5 and 2.6 and were formulated to be isoenergetic, isonitrogenous, and isostarch. Substrates were anaerobically incubated in sealed culture vials (100 mL) for 6, 24 or 48 h. Three incubation runs were conducted within two consecutive weeks. With the increase of the dietary SPR, the gas production (GP), in vitro dry matter disappearance (IVDMD) and concentration of MCPS and total volatile fatty acids (TVFA) linearly increased after 6 h of incubation (p ≤ 0.01), whereas they quadratically increased and peaked at the SPR of 2.3 after 24 and 48 h of incubation (p < 0.05). In response to dietary SPR increasing, the in vitro neutral detergent fiber disappearance (IVNDFD) quadratically increased (p < 0.01), and the ammonia nitrogen (NH3-N) concentration linearly decreased (p < 0.01) after 6, 24 and 48 h of incubation. Based on the presented results, an SPR of 2.3 is recommended for formulating a diet due to its greatest IVDMD, IVNDFD, GP, TVFA and MCPS. However, as the results obtained are strictly dependent on the in vitro conditions, further in vivo studies are needed to verify our findings.

PSXII-15 Impacts of Forage Maturity and Apple Cider Vinegar Supplementation on Fermentation Parameters Using Ruminal Batch Culture

Abstract Grassfed dairy production systems often rely on alternative diet supplements such as apple cider vinegar (ACV) to improve productivity. The objectives of this study were to 1) compare rumen fermentative patterns resulting from diets consisting of forages harvested at mature and vegetative stages, and 2) evaluate the effects of ACV supplementation on fermentation metrics of vegetative forage mixtures using ruminal batch culture, performed as two different experiments. In each experiment, treatments were arranged as a randomized design with three periods per experiment. In experiment 1, 15 mL tubes were supplemented with 1.0 g DM of either vegetative 50% red clover + 50% orchardgrass (VEG) or mature 50% red clover + 50% orchardgrass (MAT). Tubes were inoculated with a 3:1 buffer: rumen fluid mixture (12 mL) and incubated at 39ºC under anerobic conditions for 48 h. In experiment 2, tubes received either 1.0 g DM VEG substrate only or 1.0 g DM VEG substrate + 0.125 mL ACV. Samples were collected at 0, 1, 2, 4, 6, 8, 12, 18, 24, and 48 h, pooled, and analyzed for carbohydrates (WSC), pH, in vitro DM disappearance (IVDMD), methane (CH4), and ammonia N (NH3-N). Data were analyzed using PROC GLIMMIX of SAS at P ≤ 0.05. The VEG treatment produced more CH4 than the MAT treatment (4.98 mg/ dL v. 2.87 mg/ dL; P &amp;lt; 0.0001); however, CH4 from the VEG treatment was not affected by ACV. Tubes receiving VEG had greater WSC (2.39 mg/mL v. 1.56 mg/mL; P ≤ 0.05), IVDMD (81.7% v. 77.3%; P ≤ 0.05), and mean pH compared with those receiving MAT. Tubes receiving MAT had greater concentrations of NH3-N (P &amp;lt; 0.01) compared with tubes receiving VEG. Fermentation metrics of VEG tubes were not affected by ACV; however, considerations need to be made for forage maturity.

Effects of País grape marc inclusion in high and low forage diets: ruminal fermentation, methane production and volatile fatty acids

The objective of this study was to evaluate the effects of the inclusion of País grape marc (GM) in high (HF) and low forage (LF) ruminant diets on rumen methane (CH4) production and fermentation parameters in an in vitro (batch) culture. Experimental treatments replaced forage for GM at increasing concentrations (0, 10%, 20% dry matter [DM]) in the incubation substrates. Gas production (GP) and CH4 production were measured at 6, 12 and 24 h of incubation and in vitro DM disappearance, volatile fatty acids (VFA) and ammonia nitrogen (NH3-N) were determined at 24 h. The inclusion of 10% and 20% of GM reduced NH3-N concentrations (p < 0.001) by 48% and 58% respectively, and GM20 inclusion reduced BCVFA concentrations (p = 0.049) by 21% for HF and by 11% LF. Inclusion of 20% GM reduced the percentage of CH4 in gas (p = 0.038), CH4 production (p = 0.004) and CH4 yield (p = 0.027), but leads to a reduction of in vitro dry matter disappearance (IVDMD) (p < 0.001), gas production (p < 0.001) and total VFA (p = 0.001). In conclusion, in batch culture conditions, partial substitution of fibre sources by País GM in high and low fibre diets has the potential to reduce NH3-N concentrations and CH4 production and yield with a reduction of IVDMD. HIGHLIGHTS País GM reduces up to 58% in vitro NH3-N rumen concentrations regardless of forage level in the diet. Partial substitution of fibre sources with País GM reduces methane production by up to 15%. Partial substitution of forage sources with País grape marc has the potential to improve livestock systems sustainability.

Comparing the Effects of a Pine (Pinus radiata D. Don) Bark Extract with a Quebracho (Schinopsis balansae Engl.) Extract on Methane Production and In Vitro Rumen Fermentation Parameters

Simple SummaryLivestock production systems are responsible for 37 and 64% of total anthropogenic methane (CH4) and ammonia (NH3) overall planet emissions, respectively. Due to the growing demand for meat and milk, mitigating their environmental impact is a major concern. A novel tannin-rich phenolic extract from radiata pine bark (PBE) has the potential to reduce CH4 and NH3 nitrogen (NH3-N) production and modulate rumen fermentation but has not been compared with other commercial phenolic extracts. This study compared PBE with a quebracho extract (QTE). Both extracts decreased butyrate proportion, CH4, total volatile fatty acids, NH3-N production, and increased acetate proportion. Inclusion of QTE increased the propionate proportion but decreased DM disappearance. Results indicate that PBE has the potential to contribute to sustainable livestock production; however, further in vivo studies are needed to verify our results.The aim of this study was to compare the effects of a pine (Pinus radiata D. Don) bark extract (PBE) with a quebracho (Schinopsis balansae Engl.) extract (QTE) on methane (CH4) production and in vitro rumen fermentation parameters. A forage diet supplemented with PBE or QTE (0, 2 and 4% dry matter (DM) basis) was incubated for 24 h to determine in vitro DM disappearance (IVDMD), CH4, volatile fatty acids (VFA), and ammonia nitrogen (NH3-N) production. Differences were analyzed using Tukey’s test, orthogonal contrasts, hierarchical clustering heatmap (HCH), and principal component analysis (PCA). Both extracts (4% DM) decreased butyrate (Bu; p = 0.001), CH4 (p = 0.005), total VFA (p < 0.001), and NH3-N (p = 0.006) production and increased acetate (Ac; p = 0.003) without affecting the partitioning factor (p = 0.095). Propionate (Pr; p = 0.016) was increased, whereas IVDMD (p = 0.041) was decreased with QTE (4% DM). The inclusion of QTE (2% DM) decreased CH4 production (p = 0.005) and the (Ac + Bu)/Pr ratio (p = 0.003), whereas PBE (2% DM) decreased the NH3-N (p = 0.006) and total VFA production (p < 0.001). The HCH and PCA indicate a negative correlation (r = −0.93; p < 0.001) between CH4 production and tannins. In conclusion, PBE shares many of the effects generated by QTE on ruminal fermentation, although the magnitude of these effects depends on concentration. The PBE could be used as an additive in ruminant diets to reduce CH4 and NH3-N production without reducing IVDMD or increasing propionate, but further in vivo studies are required to clarify its effects on animal production.

212 The Effects of Propionibacterium Acidipropionici P169 in an in Vitro Ruminal Acidosis Model

Abstract The objective was to evaluate the effect of Propionibacterium acidipropionici P169 (PA) concentration on fermentation characteristics in a ruminal acidosis in vitro model. Ruminal acidosis is a common metabolic disorder in feedlot cattle characterized by a low rumen pH. The experiment included 5 treatments in a completely randomized design. Treatments included a negative control (NCON), 5 × 105 colony forming units (CFU) PA (PA5), 5 × 106 CFU PA (PA6), 5 × 107 CFU PA (PA7), and a positive control with greater forage inclusion (PCON). Flasks for NCON, PA5, PA6, and PA7 contained 8.75 g of substrate (70% corn, 15% DDG, 15% silage) while substrate for PCON flasks contain additional silage (40% corn, 15% DDG, 45% silage). Treatments were run in duplicate and the experiment was replicated 3 times. All flasks included 175 mL of inoculum (4 McDougall’s buffer:1 rumen fluid). Flasks were incubated at 39◦C for 36 hours and sample aliquots were collected every 4 hours. The MIXED procedure of SAS 9.4 was used for statistical analysis with a repeated measures analysis. A treatment by hour interaction (P &amp;lt; 0.01) was observed for pH; at hour 8, PCON was the least and PA5 was the greatest. From 20 to 36 h, PCON had the greatest pH. There was no treatment by hour interaction (P = 0.99) observed for redox potential. However, treatment affected (P &amp;lt; 0.01) redox potential with PCON being greater than PA6, PA7, and NCON, with PA5 being intermediate. In vitro dry matter disappearance (IVDMD) tended (P = 0.09) to be affected by treatment; PA5, PA6, and PA7 were greater than PCON. In conclusion, Propionibacterium acidipropionici P169 concentrations affected IVDMD, pH, and redox in a ruminal acidosis in vitro model.

The In Vitro Digestion and Fermentation Characteristics of Feedstuffs Inoculated With Cecal or Colic Fluid of Dezhou Donkey

The present study was conducted to evaluate the in vitro dry matter disappearance (IVDMD) and fermentation characteristics of 6 fibrous feedstuffs incubated with donkey cecal or colic microorganisms. The fibrous feeds were corn straw, wheat straw, peanut vine, peanut shell, wheat shell and wheat bran (WB), which are commonly applied in large-scale donkey farms in China. After 48 hours fermentation, the highest IVDMD occurred in WB, and the lowest occurred in peanut shell (P < .05) regardless what inoculum applied. The IVDMD was positively correlated with OM (R = 0.42, P < .01), CP (R = 0.76, P < .01) and EE (R = 0.56, P < .01), while it was negatively correlated with NDF (R = 0.75, P < .01) and ADF (R = 0.79, P < .01). In terms of volatile fatty acids (VFAs), the greatest net VFA production also occurred in WB (P < .05). The acetate and branched-chain volatile fatty acid proportions were greater in the colon culture fluids than in caecum (P < .05), but the propionate proportions were lower in colon than in caecum (P < .05). This resulted in an increase in the ratio of acetate to propionate in colon culture fluids. In summary, based on the highest IVDMD, net VFA production and CP content occurring with the lowest contents of both NDF and ADF, WB had the highest nutritive value compared to other fibrous substrates. The extent of feed degradation and fermentation depended mainly on the nature of the incubated feedstuffs. Nevertheless, further study is required to investigate these fibrous feeds on hindgut fermentation and in vivo nutrient digestibility.

PSXIV-6 País grape marc (Vitis vinifera, País) inclusion in concentrate diets reduces ammonia nitrogen but not methane production in an in vitro batch culture

Abstract País Grape (Vitis vinifera L.) is an ancestral variety used in Chilean wine industry. It has a higher content of proanthocyanidins than commercial varieties such as Carmenère or Pinot Noir, resulting in País grape marc (PGM) with high contents of condensed tannins. As such, PGM inclusion in ruminant diets would have the potential to reduce enteric methane (CH4) emissions and decrease urinary N excretion. The objective of this study was to evaluate the effects of substitution of mixed hay (MH) with PGM in a high concentrate diet [65% dry matter (DM)] on in vitro dry matter disappearance (IVDMD), ruminal fermentation parameters, gas and CH4 production. Treatments were: T1 (Control) = 20% MH, 15% corn silage, 65% concentrate; T2 = 10% MH, 10% PGM, 15% corn silage, 65% concentrate; T3 = 20% PGM, 15% corn silage, 65% concentrate. The study was a randomized complete design with 3 treatment and 3 replicates, incubated for 24 h at 39º C. Data were compared by Tukey test and polynomial contrasts. There was a linear reduction in NH3-N (P = 0.001) as dietary PGM increased. Inclusion of PGM reduced NH3-N by 50% when added at 10% DM, and 71.7% at 20% DM. However, there also was 4% reduction in IVDMD (P ≤ 0.001) and gas production (P = 0.012) in the 20% GM diet. There were no treatment effects (P ≥ 0.05) on CH4 production or yield. Fermentation efficiency determined by the partition factor increased linearly (P = 0.013) as PGM inclusion increased, suggesting that it increases organic matter to be degraded. Based on this study it could be concluded that PGM is an alternative source of fiber for ruminants on concentrate diets, as it can result in improved rumen fermentation efficiency and a substantial reduction in ruminal ammonia nitrogen concentration (NH3-N).

PSXIII-4 Effects of “País” grape marc on in vitro methane production and ruminal fermentation parameters of a forage diet

Abstract Grape marc (GM) is a viticulture by-product used as cattle supplement in periods of shortage of conventional feed sources. It contains fats, high concentrations of polyphenols and has been reported to reduce enteric methane (CH4) emissions. In-vitro batch culture was used to study the effects of substitution of mixed hay (MH) for a traditional Chilean variety (Vitis vinifera “País”) of GM on in vitro dry matter disappearance (IVDMD), rumen fermentation parameters (short chain fatty acids, pH, partitioning factor), gas and CH4 production in a 60% forage diet (dry matter, DM). The study was a randomized complete design with 3 treatments and 3 replicates, incubated for 24 h at 39º C. Treatments were: T1 (Control): 20% MH, 40% corn silage, 40% concentrate; T2 = 10% MH, 10% GM, 40% corn silage, 40% concentrate; T3 = 20% GM, 40% corn silage, 40% concentrate. Means were compared with the Tukey test (P &amp;lt; 0.05), and polynomial contrasts. Substitution of MH with GM significantly reduced ammonia nitrogen (NH3-N) by 50% (P &amp;lt; 0.05), although it did not affect IVDMD, gas production or other rumen fermentation parameters (P &amp;gt; 0.05). Total CH4 (mg) linearly decreased (P = 0.013) as concentrations of GM increased. Methane production (mg/g DM incubated) and yield (mg/g DM digested) decreased linearly (P = 0.002 and P = 0.003, respectively) as inclusion of GM increased. Inclusion of GM at 20% reduced CH4 production by 19% and CH4 yield by 16.4%. These results indicate that partial substitution of dietary fiber sources with traditional Chilean País GM in high fiber diets is a viable feeding alternative, and can decrease environmental impact (lower CH4 and ammonia emissions) of ruminant livestock, without negatively affecting rumen fermentation parameters.

PSI-8 Evaluating the Effects of Individual Eating Rates of Feedlot Heifers on Ruminal Fermentation Using an Ex vivo Model

Abstract The objective was to determine if the eating rate of individual feedlot heifers affects ruminal fermentation using an ex vivo model. Differences in eating rate could affect ruminal fermentation and predispose an animal to be susceptible to metabolic disorders. From a contemporary group of Simmental × Angus heifers (n = 90; BW = 323 kg), 14 heifers were selected for divergent individual eating rates. During the initial 30 d on the finishing diet, a GrowSafe feed intake system was used to identify the heifers with the 7 fastest (7.60 kg DM / h; 9.25 kg DMI in 1.2 h) and 7 slowest (1.38 kg DM / h; 9.24 kg DMI in 6.7 h) eating rates. Prior to feeding, rumen fluid was collected via esophageal tubing 1 d after intake evaluation period. Each rumen fluid sample was mixed with McDougall’s buffer and a common feed substrate (similar to finishing diet). Then the samples were incubated for 24 and 48 h. In vitro dry matter disappearance (IVDMD), pH, volatile fatty acids (VFA), and ammonia were measured following incubation. The MIXED procedure of SAS 9.4 was used for statistical analysis. No eating rate by incubation time interactions (P ≥ 0.11) were observed. Although heifer eating rate did not affect (P = 0.65) IVDMD, values were greater (P &amp;lt; 0.01) at 48 h compared with 24 h. While time affected pH as it decreased (P &amp;lt; 0.01) from 24 to 48 h, heifer eating rate did not affect (P = 0.84) pH. Eating rate had no effect (P ≥ 0.10) on ammonia, total VFA, and molar proportions of acetate, propionate, isobutyrate, butyrate, valerate, and isovalerate at 24 h. Overall, the results indicated individual eating rates of feedlot heifers did not affect ruminal fermentation using an ex vivo model.

Feeding Value Assessment of Substituting Cassava (Manihot esculenta) Residue for Concentrate of Dairy Cows Using an In Vitro Gas Test.

Simple SummaryCassava (Manihot esculenta) residue is a by-product of cassava processing. Although it contains residual nutrients, it is highly perishable. Decayed cassava residue pollutes the environment and leads to major losses in feed. If cassava residue could be utilized as a dairy cow feedstuff, these problems could be solved. Our study showed that cassava residue is a good alternative to concentrate in the feed of Holstein cows. Furthermore, our data demonstrate the efficacy of the application of cassava residue as a feed for dairy cows and could help solve the shortage of feed resources in China.The feeding value of replacing concentrate with cassava (Manihot esculenta) residue in the feed of Holstein cows was confirmed using an in vitro gas test. The treatments consisted of 0% (control, CON), 5%, 10%, 15%, 20%, 25%, and 30% inclusion of cassava residue in fermentation culture medium composed of buffer solution (50 mL) and filtrated rumen fluid (25 mL). The parameters analyzed included the kinetics of gas production and fermentation indexes. Forty-eight hours later, there were no significant differences on in vitro dry matter disappearance (IVDMD), pH, and microbial crude protein (MCP) content among treatments (p > 0.05). However, the “cumulative gas production at 48 h” (GP48), the “asymptotic gas production” (A), and the “maximum gas production rate” (RmaxG) all increased linearly or quadratically (p < 0.01). The GP48 was significantly higher in the 25% treatment compared to the other treatments, except for the 30% (p < 0.01). The A was significantly larger in the 25% treatment compared to the other treatments, except for the 20% and 30% (p < 0.01). The RmaxG was distinctly larger in the 25% treatment compared to other treatments (p < 0.01); moreover, the “time at which RmaxG is reached” (TRmaxG) and the “time at which the maximum rate of substrate degradation is reached” (TRmaxS) were significantly higher in the 25% treatment than the CON, 20%, and 30% treatments (p < 0.01). Additionally, the content of ammonia-N (NH3-N) in all treatments showed linearly and quadratically decreases (p < 0.01), whereas total volatile fatty acid (VFA), iso-butyrate, butyrate, and iso-valerate contents changed quadratically (p = 0.02, p = 0.05, p = 0.01, and p = 0.02, respectively); all of these values peaked in the 25% treatment. In summary, the 25% treatment was associated with more in vitro gas and VFA production, indicating that this cassava residue inclusion level may be used to replace concentrate in the feed of Holstein cows. However, these results need to be verified in vivo.

Effect of replacement of soybean meal with rice gluten meal on in vitro fermentation characteristics of total mixed ration

An in vitro study was conducted to assess the effect of using rice gluten meal as a substitute of soybean meal (SBM) in ruminant diet. The SBM comprising 12.5% whole diet [total mixed ration (TMR)] was substituted by rice gluten meal (RGM) on w/w basis at 0, 25, 50, 75 and 100% level. In vitro dry matter disappearance (IVDMD), organic matter disappearance (IVOMD), net gas production, methane production and fermentation efficiency of TMRs was assessed. The chemical composition of TMRs revealed decrease in total ash, acid detergent fiber and total carbohydrate contents and increase in organic matter, crude protein, ether extract, neutral detergent fiber, acid detergent lignin, hemicellulose, neutral detergent insoluble crude protein and acid detergent insoluble crude protein contents with increase in RGM in TMRs. No significant difference in net gas production, IVDMD and IVOMD was observed between the TMR treatments having graded levels of RGM and control. The NH3-N in TMRs declined with increase in RGM and was highest (P<0.05) in control. The relative proportion of propionic acid and isovaleric acid was highest in TMR 3 (50% RGM replacing SBM); whereas relative proportion of butyric acid was lowest in TMR 3. CH4 production showed decline with increase in RGM in TMRs beyond 25% level replacing SBM. The H-recovery was lowest in control TMR. The hydrogen consumed via CH4 as compared to the hydrogen consumed via VFA was lowest in TMR 3. The fermentation efficiency was highest in TMR 3. Thus, RGM could replace up to 100% of soybean meal in TMR of ruminants without any adverse effect on nutrient digestibility which is equivalent to 12.5% of whole dietary dry matter.

Chemical composition and nutritional value of leaves and pods of Leucaena leucocephala, Prosopis laevigata and Acacia farnesiana in a xerophilous shrubland

The objective of this study was to determine the nutritional value of three leguminous trees heavily selected by goats in a xerophilous shrubland. Chemical composition and in vitro dry matter disappearance (IVDMD) of leaves and pods from leucaena (Leucaena leucocephala), mesquite (Prosopis laevigata), and huisache (Acacia farnesiana) is presented. Crude protein (CP) ranged from 17.3% for leaves of huisache to 21.9% for leucaena. The neutral detergent fiber (NDF) content ranged from 39.0 to 40.3 with no difference among fodder threes. Across tree species, mean IVDMD was 61.6% for pods and 52.2% for leaves. IVDMD for leaves was highest (p &lt; 0.01) for leucaena (54.9%) and lowest for huisache (47.3%). Condensed tannins in an acetonic extract were highest for leaves of huisache (45.3 mg CE/g DM) and lowest for mesquite (25.9 mg CE/g DM). Pods and leaves of huisache presented the highest number of secondary metabolites, mainly related to hydroxybenzoic acid and flavonols; leucaena and mesquite presented mainly flavonols and anthocyanins. It was concluded that leaves and pods of leucaena, mesquite, and huisache constitute valuable forages for ruminant livestock due to their low fiber, high CP levels, moderate in vitro fermentation characteristics and high mineral content.

Addition of polyvinyl alcohol (PVA) to lactated Ringer’s solution (LRS) prevents equine embryos from adhering to plastic search dishes after initial recovery

To assess the impact of protein on fermentation by equine cecal microorganisms, cecal fluid from 4 cecally cannulated horses was used to inoculate fermentation bottles containing buffer, forage, and supplemental protein. In experiment 1, sodium caseinate (SC) provided 0, 0.5%, 1%, 2%, or 4% additional crude protein (CP) to bottles containing alfalfa or native warm-season prairie grass hay. Bottles were equipped with continuous gas pressure monitors and placed into a shaking incubator for 48 hours at 39°C. Cultures with alfalfa had greater (P < .0001) in vitro dry matter disappearance (IVDMD), neutral detergent fiber disappearance (NDFD), acid detergent fiber disappearance (ADFD), cumulative gas production, and total volatile fatty acid (VFA). Sodium caseinate increased gas production (P ≤ .05) and decreased pH (P < .003) in cultures with grass hay. Sodium caseinate at 1%, 2%, or 4% additional CP increased IVDMD, NDFD, and ADFD (P < .01), while 4% additional CP also increased total VFA (P < .01). For experiment 2, SC, fishmeal, soybean meal (SBM), whey, porcine blood plasma, and L-lysine hydrochloride were added to supply 2% additional CP to cultures with grass hay. All protein sources decreased pH and increased IVDMD, NDFD, and ADFD (P ≤ .01), with the largest effects elicited by SC, L-lysine, and whey (P ≤ .05). Total VFA (P ≤ .04) and gas (P ≤ .05) production increased with L-lysine, whey, SC, SBM, and fishmeal. While protein supplementation had minimal effects on cultures containing alfalfa, it altered fermentation of grass hay, more notably with more soluble protein sources.

Effects of Sodium Caseinate and Varying Protein Sources on In Vitro Fermentation of Forages by Mixed Equine Cecal Microorganisms

To assess the impact of protein on fermentation by equine cecal microorganisms, cecal fluid from 4 cecally cannulated horses was used to inoculate fermentation bottles containing buffer, forage, and supplemental protein. In experiment 1, sodium caseinate (SC) provided 0, 0.5%, 1%, 2%, or 4% additional crude protein (CP) to bottles containing alfalfa or native warm-season prairie grass hay. Bottles were equipped with continuous gas pressure monitors and placed into a shaking incubator for 48 hours at 39°C. Cultures with alfalfa had greater (P < .0001) in vitro dry matter disappearance (IVDMD), neutral detergent fiber disappearance (NDFD), acid detergent fiber disappearance (ADFD), cumulative gas production, and total volatile fatty acid (VFA). Sodium caseinate increased gas production (P ≤ .05) and decreased pH (P < .003) in cultures with grass hay. Sodium caseinate at 1%, 2%, or 4% additional CP increased IVDMD, NDFD, and ADFD (P < .01), while 4% additional CP also increased total VFA (P < .01). For experiment 2, SC, fishmeal, soybean meal (SBM), whey, porcine blood plasma, and L-lysine hydrochloride were added to supply 2% additional CP to cultures with grass hay. All protein sources decreased pH and increased IVDMD, NDFD, and ADFD (P ≤ .01), with the largest effects elicited by SC, L-lysine, and whey (P ≤ .05). Total VFA (P ≤ .04) and gas (P ≤ .05) production increased with L-lysine, whey, SC, SBM, and fishmeal. While protein supplementation had minimal effects on cultures containing alfalfa, it altered fermentation of grass hay, more notably with more soluble protein sources.

Effects of inclusion of purple prairie clover (Dalea purpurea Vent.) with native cool-season grasses on in vitro fermentation and in situ digestibility of mixed forages

BackgroundIncorporation of legume species into native North American pastures is considered an effective method to increase native pasture productivity and improve the nutritive value of forage. This study evaluated the effects of inclusion of purple prairie clover (PPC, Dalea purpurea Vent.), a native legume forage, with native cool-season grasses on the in vitro fermentation and in situ digestibility of mixed forages.MethodsWhole plant PPC and mixtures of cool-season grasses were harvested when the PPC reached the vegetative (VEG), full flower (FL) and seedpod (SP) stages, and were combined in ratios (DM basis) of 0:100, 25:75, 50:50, 75:25 and 100:0 at each maturity. In vitro ruminal incubations using these mixtures were conducted for 48 h to determine gas production (GP), in vitro DM disappearance (IVDMD), total volatile fatty acids (VFA) and ammonia-N production. Mixtures of forages harvested when the PPC reached the FL stage and 50:50 mixture of forages harvested at VEG, FL and SP stages were incubated in the rumen of three heifers for 0, 2, 6, 12, 24, 48, 72 and 96 h to determine in situ degradabilities of DM, neutral detergent fibre (aNDF) and crude protein (CP).ResultsContents of aNDF and ADF increased (P < 0.01), while CP decreased (P < 0.001) as PPC matured. Concentrations of extractable condensed tannins in PPC ranked as FL > VEG > SP (P < 0.05). Regardless of PPC proportions in the mixture, GP decreased (P < 0.05) with increasing PPC maturity. Increasing PPC proportions linearly increased (P < 0.001) GP, IVDMD and total VFA at VEG, but linearly decreased (P < 0.001) them at SP. Irrespective of PPC maturity, ammonia-N production linearly increased (P < 0.01) with increasing proportions of PPC and the concentration was higher (P < 0.05) at VEG than at FL and SP stages. Increasing proportion of PPC at either maturity linearly increased (P < 0.001) molar percentage of acetate (A) and branched-chain VFA, but linearly decreased (P < 0.001) molar percentage of propionate (P), resulting in a linearly increase (P < 0.001) in the A:P ratio. Increasing FL PPC in the mixture linearly and quadratically (P < 0.01) increased a (soluble fraction), but linearly and quadratically decreased (P < 0.01) b (potentially degradable fraction) for DM and aNDF, resulting in linear (P < 0.05) and quadratic (P < 0.01) increases in DM and aNDF maximum potential degradabilities (a + b). Effective degradabilities of DM and aNDF were also linearly and quadratically increased (P < 0.05), and CP was quadratically increased (P < 0.05) with increasing FL PPC, with the greatest effective degradability being observed with ratios between 50:50 and 75:25. Ruminal maximum potential degradabilities of DM and aNDF decreased (P < 0.001) as the forage matured. Effective degradability of DM ranked as VEG > FL > SP (P < 0.001), whereas the effective degradability of aNDF was similar between VEG and FL and both were greater (P < 0.01) than SP.ConclusionsInclusion of vegetative PPC in a mixed forage diet resulted in the greatest digestibility and incorporation of PPC before seedpod stage with native grasses had a positive effect on ruminal fermentation. Effects of PPC on ruminal digestion depend on both the stage of maturity and its proportion in mixed legume-grass pastures. Pastures containing 50% of PPC in full flower stage would likely provide the greatest quality diet to grazing ruminants subject to potential animal selectivity.

Beneficial effect of Rhodopseudomonas palustris on in vitro rumen digestion and fermentation.

As a member of photosynthetic bacteria, Rhodopseudomonas palustris, which has extraordinary metabolic versatility, has been applied as one of potential probiotics in feed industry. To explore whether R. palustris can increase rumen microbial viability and thus improve microbial fermentation, a 2×5 factorial experiment was conducted to evaluate the effect of R. palustris at dose rates of 0, 1.3, 2.6, 3.9, 5.2×106 cfu/ml on ruminal fermentation of two representative total mixed rations (HY, a ration for high-yield (>32 kg/d) lactating cows; LY, a ration for low-yield (<25 kg/d) lactating cows). After a 48 h in vitro rumen incubation, both rations resulted in different fermentation characteristics. The HY in comparison with LY group presented greater in vitro dry matter disappearance (IVDMD), cumulative gas production (GP48) and total volatile fatty acids (VFA, P<0.01). Increasing R. palustris addition linearly increased IVDMD (P<0.01) and GP48 (P<0.05), and the IVDMD increment in response to R. palustris addition was greater in LY than HY group (6.4% vs 1.4%). Meanwhile, increasing R. palustris addition also linearly enhanced microbial protein synthesis and increased total VFA production (P<0.01), especially in LY group (up to 21.5% and 24.5% respectively). Unchanged acetate and declined propionate in molar percentage were observed in response to the R. palustris addition. Furthermore, increasing R. palustris addition altered fermentation gas composition in which molar O2 proportion in headspace of fermentation system was linearly reduced by 46.1% in LY and 32.9% in HY group, respectively (P<0.01), and methane production in both ration groups was enhanced by 1.9-4.1% (P=0.02). In summary, the R. palustris addition exhibited high potential for promoting the growth of rumen microorganism and enhancing microbial fermentation towards non-glucogenic energy supply by maintaining an anaerobic environment to microbe equilibrium.

372 Effect of rumen fluid collection methodology on extent and variance of in vitro dry matter disappearance and interaction with substrate and incubation time

Abstract The objective was to evaluate the interaction of rumen fluid collection methodology, substrate, and incubation time on the extent and variance of in vitro dry matter disappearance (IVDMD). A 4×2×2 factorial design was used to test the interaction between rumen fluid collection methodology, substrates (hay and silage), and incubation time-points (24 and 48 h). Four methods of rumen fluid collection were evaluated: stomach tube (TUBE), suction strainer through rumen cannula (STRN), ruminal contents collected through cannula and squeezed through cheesecloth (SQZ), and ruminal contents blended for 1 minute and squeezed through cheesecloth (BSQZ). Four replications of each treatment were used and repeated in three periods. A methodology by substrate interaction (P &lt; 0.01) was observed for pH; hay had a greater pH than silage and the magnitude of this difference was greatest for STRN. A tendency for a methodology by substrate interaction (P = 0.06) was observed for ammonia. For TUBE ammonia was greater (P &lt; 0.01) with hay while substrate did not affect ammonia for BSQZ, SQZ and STRN. A methodology by time interaction was observed (P &lt; 0.01) for ammonia; TUBE was least at 24 h, but TUBE and BSQZ were lesser (P ≤ 0.01) than STRN and SQZ at 48 h. A tendency for a methodology by substrate interaction (P = 0.08) was observed in IVDMD; silage had greater IVDMD than hay and the magnitude of this difference was greatest for TUBE. Collection methodology affected (P &lt; 0.01) IVDMD. The greatest IVDMD was observed for STRN (64.7%), with BSQZ (59.1%) and SQZ (57.7%) being intermediate and TUBE (54.3%) being the least. A tendency for a methodology by substrate interaction (P = 0.11) was observed for variation in IVDMD; silage had greater variation than hay for TUBE. Rumen fluid collection methodology affects IVDMD and may depend on substrate.