Fractional Degradation Rate Research Articles

In vivo collagen and mixed muscle protein turnover in 2 meat-type broiler strains in relation to woody breast myopathy

Two meat-type broiler strains, strain A and strain B, were reared in floor pens (25 birds/pen; 45 pens/strain) for pectoralis (P) major collagen and mixed muscle protein turnover (PT) study from 0–56 D using primary breeder nutrition and husbandry guidelines. Forty broilers (n = 10/strain for collagen PT; n = 10/strain for mixed muscle PT) were selected at each sampling age at day 21, 28, 35, 42, and 56 and infused with 1-13C proline (Pro) and 15N-phenylalanine (Phe) which are used as amino acid tracers for collagen and mixed muscle PT measurements, respectively. Muscle and plasma samples were collected, and enrichments of 1-13C Pro and 15N-Phe were determined using mass spectrometry. Fractional synthesis rate (FSR) and fractional degradation rate (FDR) were measured for collagen and mixed muscle using precursor-product principle. At day 42, after separating the sampled broilers as myopathy (woody breast [WB] score > 1) and nonmyopathy (WB = 0), plasma metabolites were screened for differential 3-methyhistidine (3-MH) expression for both strains. Data were analyzed using one-way ANOVA using t test. Results showed that collagen and mixed muscle FSR and FDR in pectoralis major decreased (P < 0.05) for both strains as the broilers aged. FSR for collagen and FDR for mixed muscle were higher for strain B than those for strain A (P < 0.05). Total collagen was higher (P < 0.05) for strain B. Differentially expressed 3-MH in plasma was higher (P < 0.05) for myopathy-affected broilers indicating greater muscle degradation occurring in myopathy-affected broiler types for both strains. 3-MH Expression in plasma was higher for strain B than for strain A. The research findings showing an increased collagen content per unit muscle weight in pectoralis major in strain B (than in strain A) could be due to higher mixed muscle FDR and increased collagen FSR occurring during the grow-out period. The increased degradation of muscle fibers and probable replacement of muscle-specific protein with connective tissue, mainly collagen, was an evident pathophysiological phenomenon occurring in myopathy-affected broilers.

Effects of dietary supplement sources on the rate and extent of in vitro ruminal degradation of alfalfa-based diets for cattle

Two ruminally cannulated steers [928 ± 25.5 kg body weight (BW)] were fed alfalfa hay at 2.0% of BW and served as donors of rumen fluid. Treatments were early-bud alfalfa (CON) or a combination [dry matter (DM) basis] of 80% early-bud alfalfa with 20% of corn silage (CS), brome grass hay (BGH), soybean hulls (SBH), beet pulp (BP), corn grain (CORN), dried corn distillers’ grains with solubles (DDGS), or wheat middlings (MIDD). Tubes were incubated at multiple time points over a 72 h period and assessed for rate and extent of digestion. Samples were run in duplicate and replicated over 3 d. The potential extent of DM and organic matter (OM) degradation increased (P &lt; 0.001) with CS, SBH, BP, CORN, and DDGS supplementation compared with CON. All supplements except MIDD decreased (P &lt; 0.001) the fractional rates of DM and OM degradation compared with CON, with BGH, SBH, and DDGS having the lowest rates. Supplementation of SBH had the lowest (P &lt; 0.001) initial rate of DM and OM degradation. These data indicate that SBH increases the extent of digestion while reducing the initial rate of degradation, suggesting that SBH has potential to reduce the incidence of frothy legume bloat.

Effect of sample size on kinetic parameters of roughage and concentrated feeds by a semi-automated in vitro gas production system

This study aimed to evaluate the effect of different amounts of incubated samples on the kinetic parameters of in vitro fermentation of roughage and concentrated food used for feeding ruminants. Samples were prepared using 200, 300, 400, and 500 mg of air-dried roughage and concentrated sample, ground to 1 mm, and placed in 120 mL glass flasks. Next, inoculum and McDougal solution were added, and the readings were obtained using a semi-automated pressure transducer up to 96 h after the beginning of the incubations. Gas production of the non-fibrous fraction increased linearly (P &lt; 0.05) for sugarcane, Marandu grass silage, corn silage, dried corn distillers’ grains with solubles, dried brewer’s yeast, bean residue, wet brewer’s grains, sunflower meal, and Jatropha meal; quadratically (P &lt; 0.05) for Napier grass silage and cottonseed meal; and cubically (P &lt; 0.05) for castor meal and soybean meal. The degradation rate of the non-fibrous fraction reduced linearly (P &lt; 0.05) for sugarcane, Napier grass silage, and castor meal; quadratically (P &lt; 0.05) for Marandu grass silage; and cubically (P &lt; 0.05) for corn silage, soybean meal, dried corn distillers’ grains with solubles, bean residue, and cottonseed meal. Gas production of the fibrous fraction increased linearly (P &lt; 0.05) for Napier grass silage, Marandu grass silage, corn silage, dried corn distillers’ grains with solubles, bean residue, wet brewer’s grain, cottonseed meal, and sunflower meal; quadratically ( &lt; 0.05) for Jatropha meal; and cubically (P &lt; 0.05) for sugarcane, castor meal, and soybean meal. The degradation rate of the fibrous fraction increased linearly (P &lt; 0.05) for Napier grass silage, dried corn distillers’ grains with solubles, dried brewer’s yeast, wet brewer’s grains; quadratically (P &lt; 0.05) for corn silage and castor meal; and cubically (P &lt; 0.05) for sugarcane, Marandu grass silage, and bean residue. The lag time reduced linearly (P &lt; 0.05) for castor meal and dried corn distillers’ grains with solubles; quadratically (P &lt; 0.05) for Napier grass silage; and cubically (P &lt; 0.05) for sugarcane, Marandu grass silage, corn silage, soybean meal, bean residue, cottonseed meal, sunflower meal, and Jatropha meal. Thus, our findings suggest that the kinetic parameters of in vitro fermentation were affected as a function of the amount of incubated sample.

Effect of sample size on kinetic parameters of roughage and concentrated feeds by a semi-automated in vitro gas production system

This study aimed to evaluate the effect of different amounts of incubated samples on the kinetic parameters of in vitro fermentation of roughage and concentrated food used for feeding ruminants. Samples were prepared using 200, 300, 400, and 500 mg of air-dried roughage and concentrated sample, ground to 1 mm, and placed in 120 mL glass flasks. Next, inoculum and McDougal solution were added, and the readings were obtained using a semi-automated pressure transducer up to 96 h after the beginning of the incubations. Gas production of the non-fibrous fraction increased linearly (P &lt; 0.05) for sugarcane, Marandu grass silage, corn silage, dried corn distillers’ grains with solubles, dried brewer’s yeast, bean residue, wet brewer’s grains, sunflower meal, and Jatropha meal; quadratically (P &lt; 0.05) for Napier grass silage and cottonseed meal; and cubically (P &lt; 0.05) for castor meal and soybean meal. The degradation rate of the non-fibrous fraction reduced linearly (P &lt; 0.05) for sugarcane, Napier grass silage, and castor meal; quadratically (P &lt; 0.05) for Marandu grass silage; and cubically (P &lt; 0.05) for corn silage, soybean meal, dried corn distillers’ grains with solubles, bean residue, and cottonseed meal. Gas production of the fibrous fraction increased linearly (P &lt; 0.05) for Napier grass silage, Marandu grass silage, corn silage, dried corn distillers’ grains with solubles, bean residue, wet brewer’s grain, cottonseed meal, and sunflower meal; quadratically ( &lt; 0.05) for Jatropha meal; and cubically (P &lt; 0.05) for sugarcane, castor meal, and soybean meal. The degradation rate of the fibrous fraction increased linearly (P &lt; 0.05) for Napier grass silage, dried corn distillers’ grains with solubles, dried brewer’s yeast, wet brewer’s grains; quadratically (P &lt; 0.05) for corn silage and castor meal; and cubically (P &lt; 0.05) for sugarcane, Marandu grass silage, and bean residue. The lag time reduced linearly (P &lt; 0.05) for castor meal and dried corn distillers’ grains with solubles; quadratically (P &lt; 0.05) for Napier grass silage; and cubically (P &lt; 0.05) for sugarcane, Marandu grass silage, corn silage, soybean meal, bean residue, cottonseed meal, sunflower meal, and Jatropha meal. Thus, our findings suggest that the kinetic parameters of in vitro fermentation were affected as a function of the amount of incubated sample.

EFFECTS OF REPLACING LOW STARCH BY-PRODUCTS FOR BARLEY GRAIN ON in situ RUMEN DEGRADABILITY AND in vitro GAS PRODUCTION PROPERITES OF A TOTAL MIXED RATION

This study was conducted to study the effects of different sources of low starch by-products substituted for barley grain on in situ rumen degradability and in vitro gas production properties of a total mixed ration. The experimental treatments consisted of 370 g/kg roughages and 630 g/kg concentrates. The total mixed diets contained 100 g /kg dry matter (DM) barley grains (BG, control diet), sugar beet pulp (SBP, treatment 2), wheat bran (WB, treatments 3), or dried citrus pulp (DCP, treatment 4). In the first experiment, the experimental diets were evaluated for in-situ rumen degradability by the nylon bag technique. In the second experiment, treatments were evaluated for in vitro gas production parameters. Data were analyzed as a completely randomized design. The data on in situ experiment indicated that non-soluble degradation fraction (b), the fractional degradation rate (c) and potential degradability (a+b) were not affected by the diets (P&gt;0.05). However, soluble degradable fraction (a) was highest for a diet with DCP (P&lt;0.05). The in vitro gas production data showed there were no significant differences among treatments for gas produced at different times of incubation (P&gt;0.05). Besides, the potential gas production (b), and OMD did not differ among treatments (P&gt;0.05). But, the fractional rate of gas production (c) was lowest for diet with DCP (P&lt;0.05). Still, SCFA varied among various treatments (P&lt;0.05), and it was higher for DCP treatment than other groups. It concluded that replacing low starch by-products, such as dried citrus pulp and sugar beet pulp, for up to 10% of diet DM instead of barley grain can improve the DM digestibility of a total mixed ration without any adverse effect on ruminal fermentation in ruminants.

133 Porcine in vitro degradation and fermentation characteristics of heat-pretreated and multi-enzyme-supplemented soybean hulls

Abstract A study was conducted to determine effects of pretreating and supplementing soybean hulls with multi-enzyme on porcine in vitro digestion and fermentation characteristics. Treatments were untreated and heat-pretreated (160 °C and 70 psi for 20 min) soybean hulls without or with multi-enzyme in a 2 × 2 factorial arrangement. The multi-enzyme supplied 2,800 U of cellulase, 1,800 U of pectinase, 400 U of mannanase, 1,000 U of xylanase, 600 U of glucanase, and 200 U of protease/kilogram of feedstuff. Feedstuffs were subjected to in vitro digestion with porcine pepsin and pancreatin, followed by in vitro fermentation for 72 h. Accumulated gas production was recorded and modeled to estimate kinetics of gas production. On DM basis, untreated and pretreated soybean hulls contained 10.4 and 10.6% CP, and 63.2 and 49.5% ADF, respectively. Pretreatment and multi-enzyme supplementation did not interact on in vitro digestibility of DM (IVDDM). Untreated and pretreated soybean hulls did not differ in IVDDM (24.8 vs. 25.7%). Multi-enzyme increased (P &amp;lt; 0.05) IVDDM of soybean hulls by a mean of 45.5%. Pretreatment and multi-enzyme unaffected total gas production. Pretreatment and multi-enzyme interacted (P &amp;lt; 0.05) on fractional rate of degradation such that the fractional rate of degradation for pretreated soybean hulls was greater (P &amp;lt; 0.05) than that of untreated soybean hulls when soybean hulls were supplemented with multi-enzyme (0.045 vs. 0.062 h-1), but not when soybean hulls were unsupplemented with multi-enzyme (0.053 vs. 0.059 h-1). In conclusion, multi-enzyme supplementation increased IVDDM, implying that the multi-enzyme used in the study can be used to enhance utilization of soybean hulls. Heat pretreatment increased the rate of fermentation of multi-enzyme-supplemented soybean hulls, implying that the rate of fermentation of soybean hulls in the hindgut of pigs can be enhanced by a combination of heat pretreatment and multi-enzyme supplementation.

PSVIII-7 In vitro fermentation of different dietary fibers selectively changed sow gut microbiota composition

Abstract In vitro fermentation experiments with modified starch 1 (MS1), modified starch 2 (MS2), guar gum (GG), xanthan gum (XG), konjac flour (KF), wheat brain (WB), and inulin (I) were conducted for 48 h to investigate the effects on gilt gut microbiota. Fecal examples were obtained from three gilts; the fermentation kinetics parameters were analysed in Logistic-Exponential (LE) model such as the final asymptotic gas volume (Vf, ml/g), initial fractional rate of degradation at t-value=0 (FDR0, h-1), fractional rate of gas production at particular time (k, h-1) and half-time to asymptote (T1/2, h). Samples were collected after fermentation for short chain fatty acids (SCFAs) and 16S rDNA microbial analysis. MS1, MS2, and I had the highest Vf (P &amp;lt; 0.01). The k of GG and I were significant higher (P &amp;lt; 0.01). FDR0 of MS2, GG, and I were the lowest following KF, MS1, WB, and XG, successively (P &amp;lt; 0.01). T1/2 of MS1, KF, WB, and GG were lower (P &amp;lt; 0.01). MS1, MS2, and GG produced more acetate (P &amp;lt; 0.05) and total SCFAs (P &amp;lt; 0.01), and butyrate produced by MS2 was significant higher (P &amp;lt; 0.01). The microbiota composition changed dramatically after fermentation, decreasing bacteria abundance and alpha-diversity (P &amp;lt; 0.01). The relative abundance of phyla Firmicutes and Bacteroidetes decreased, while phyla Spirochaetes, Proteobacteria, Kiritimatiellaeota, and Fusobacteria were selectively promoted by DF. The LEfSe analysis showed Proteobacteria, Gammaproteobacteria, and Aeromonadales were enriched in MS1 treatment; Clostridiales, Clostridia, and Anaerosporobacter were enriched in MS2 treatment; Bacteroidales, Bacteroidia, and Bacteroidetes were enriched in GG treatment; Ruminococcaceae and Ruminococcaceae_UCG_013 were enriched in XG treatment; Lachnospiraceae, Lachnospiraceae_NK4A136_group, and Ruminiclostridium were enriched in KF treatment; Enterobacteriales, Enterobacteriaceae, and Lactobacillales, were enriched in I treatment. In conclusion, different type of DFs may play a specific role in gilt gut microbiota changing and composition.

Prediction of in vivo organic matter digestibility of beef cattle diets from degradation parameters estimated from in situ and in vitro incubations

AbstractThe objective of this meta-analysis study was to develop and validate equations estimated from in situ and in vitro methods to predict in vivo ruminal digestibility of organic matter (OM) of beef cattle diets. The database was composed of individual data of 23 diets from six experiments. Information collected from these studies was: in vivo digestibility and degradation parameters of OM calculated from in situ and in vitro incubations. The values of estimated times for the in situ and in vitro incubations to access in vivo digestibility of OM, and differences between degradation at 24, 48 and 72 h (in situ and in vitro) and in vivo digestibility were analysed in a model that included the fixed effects of forage neutral detergent fibre level. Thereafter, a multiple stepwise regression was carried out using OM digestibility as a dependent variable and degradation parameters (A = water-soluble fraction; B = potentially degradable water-insoluble fraction; and kd = degradation rate of fraction B) as independent variables. Equation validation was performed using data from a seventh experiment that have the same methods than previous studies. Stepwise regression results showed that the kd contributed significantly in most of the algorithms derived to predict in vivo digestibility. Validation analysis showed that equations developed from both in vitro and in situ incubations accurately estimated the in vivo digestibility of OM (P &gt; 0.05). Our results suggest that equations developed to estimate OM digestibility showed both precision and accuracy; however, in situ method presented better results than in vitro.

Evaluation of different inclusion levels of dry live yeast impacts on various rumen parameters and in situ digestibilities of dry matter and neutral detergent fiber in growing and finishing beef cattle.

This study evaluated the effects of supplementing dry live yeast (LY; Saccharomyces cerevisiae) on in vitro gas production (IVGP) fermentation dynamics, pH, and CH4 concentration at 48 h, and in situ rumen parameters and digestibility of DM (DMD) and NDF (NDFD) of growing cattle during 3 feeding phases: grower (GRW) for 17 d (38% steamed-flaked corn; SFC), transition (TRANS) for 15 d (55.5% SFC: 1.2 Mcal/kg NEg), and finisher (FIN) for 13 d (73% SFC: 1.23 Mcal/kg NEg). Twenty British-crossbred, ruminally cannulated steers (183 kg ± 44 kg) 6 mo of age were blocked by weight into 5 pens containing Calan gate feeders and received a control (CON) diet (17.2% CP, 35.8% NDF, 86.7% DM) without LY on days -12 to 0. After that, animals were randomly assigned to treatments (TRT), 5 animals per TRT: CON or LY at inclusion rates of 5 g/d (LY1), 10 g/d (LY2), or 15 g/d (LY3) top dressed every morning at 0800 for 45 d. The DMD and NDFD were assessed during 7 separate collection days using in situ nylon bags containing 5 g of GRW, TRANS, or FIN diets, incubated at 1200 for 48 h. Protozoa counts (PC) were determined during 5 collection periods. Data were analyzed as a repeated measure within a randomized complete block design, assuming a random effect of the pen. For GRW, TRT altered the total gas production of the nonfiber carbohydrate (NFC; P = 0.045) and the fractional rate of degradation (kd) of the fiber carbohydrate (FC) pool (P = 0.001) in a cubic pattern (P ≤ 0.05): LY2 had the most gas production and fastest kd. TRT also influenced DMD (P = 0.035) and NDFD (P = 0.012) with LY2 providing the greatest digestibility. For TRANS, TRT tended to affect the NFC kd (P = 0.078) and influenced pH (P = 0.04) and DMD (P < 0.001) in which LY2 yielded the fastest kd, highest pH, and greatest DMD. For FIN, there was an effect of TRT on total gas production (P < 0.001) and kd (P = 0.004) of the NFC pool, FC kd (P = 0.012), in vitro CH4 concentration (P < 0.001), PC (P < 0.001), DMD (P = 0.039), and NDFD (P = 0.008). LY1 had the highest PC and provided the greatest DMD and NDFD. LY2 had the fastest kd of both the NFC and FC pools and had the least CH4 concentration. LY3 had the greatest NFC gas production. No specific dose-response pattern was observed, but 10 g/d provided the most beneficial result for all diets. We concluded that supplementation with LY affected IVGP as well as ruminal parameters and digestibilities.

Effects of Gas Production Recording System and Pig Fecal Inoculum Volume on Kinetics and Variation of In Vitro Fermentation using Corn Distiller's Dried Grains with Solubles and Soybean Hulls.

Simple SummaryVarious in vitro methodologies have been developed and used to estimate the digestibility of feed ingredients, such as corn distillers dried grains with solubles (cDDGS) and soybean hulls (SBH) which contain high concentrations of dietary fiber. This study evaluated two in vitro gas production recording systems (manual vs. automated) and two initial fecal inoculum volumes (30 vs. 75 mL) on the parameters of in vitro fermentation of cDDGS and SBH. The results showed that the use of 75-mL inoculum volume with 0.5 g substrate tended to reduce the variation of measurements compared to the 30-mL inoculum volume with 0.2 g substrate regardless of the gas production recording system. These findings suggest that using larger inoculum volume with more substrate increases the precision of measurements. Furthermore, the automated system decreases labor for conducting the assay.An experiment was conducted to investigate the effect of inoculum volume (IV), substrate quantity, and the use of a manual or automated gas production (GP) recording system for in vitro determinations of fermentation of corn distillers dried grains with solubles (cDDGS) and soybean hulls (SBH). A 2 × 2 × 2 factorial arrangement of treatments was used and included the factors of (1) ingredients (cDDGS or SBH), (2) inoculum volume and substrate quantity (IV30 = 0.2 g substrate + 30 mL inoculum or IV75 = 0.5 g substrate + 75 mL inoculum), and (3) GP recording system (MRS = manual recording system or ARS = automated recording system). Feed ingredient samples were pre-treated with pepsin and pancreatin, and the hydrolyzed residues were subsequently incubated with fresh pig feces in a buffered mineral solution. The GP recording was monitored for 72 h, and the kinetics were estimated by fitting data using an exponential model. Compared with SBH, cDDGS yielded less (p < 0.01) maximal gas production (Gf), required more time (p < 0.02) to achieve half gas accumulation (T/2), and had less (p < 0.01) fractional rate of degradation (µ) and in vitro fermentability of dry matter (IVDMF). Using the ARS resulted in less IVDMF (p < 0.01) compared with MRS (79.0% vs. 81.2%, respectively). Interactions were observed between GP recording system and inoculum volume and substrate quantity for Gf (p < 0.04), µ (p < 0.01), and T/2 (p < 0.04) which implies that increasing inoculum volume and substrate quantity resulted in decreased Gf (332 mL/g from IV30 vs. 256 mL/g from IV75), µ (0.05 from IV30 vs. 0.04 from IV75), and T/2 (34 h for IV30 vs. 25 h for IV75) when recorded with ARS but not MRS. However, the recorded cumulative GP at 72 h was not influenced by the inoculum volume nor recording system. The precision of Gf (as measured by the coefficient of variation of Gf) tended to increase for IV30 compared with IV75 (p < 0.10), indicating that using larger inoculum volume and substrate quantity (IV75) reduced within batch variation in GP kinetics. Consequently, both systems showed comparable results in GP kinetics, but considering convenience and achievement of consistency, 75 mL of inoculum volume with 0.5 g substrate is recommended for ARS.

Chemical composition and in vitro ruminal fermentation of pigeonpea and mulberry leaves

Mulberry and pigeonpea trees are two widely distributed trees in southwest regions of China, and grow well in summer and winter season respectively. The present study is to investigate the nutritive value of mulberry and pigeonpea leaves by using in vitro ruminal fermentation. Pigeonpea leaves were harvested in February, October, November and December, while mulberry leaves were harvested in May, July, September, October. Comparisons of chemical composition, kinetics of in vitro gas production, methane production, dry matter degradation and VFA production of pigeonpea and mulberry leaves were performed by using in vitro ruminal batch culture system. Pigeonpea and mulberry leaves had crude protein varying from 186 to 208 and 209 to 269 g/kg dry matter, respectively, and neutral detergent fiber ranging from 395 to 456 and 252 to 336 g/kg dry matter, respectively. In vitro fermentation indicated that pigeonpea leaves had lower in vitro dry matter degradation and theoretical maximum of gas production, but greater initial fractional rate of degradation and acetate to propionate ratio in comparison with mulberry leaves. Meanwhile, harvest time influenced the acetate to propionate ratio of both leaves. In conclusion, pigeonpea and mulberry leaves have protein content larger than 180 g/kg dry matter, and can be alternative protein resource for ruminants. In addition, harvest time significantly affect the fermentation pathway of these two leaves.

Physico-chemical properties of purified starch affect their in vitro fermentation characteristics and are linked to in vivo fermentation characteristics in pigs

Fermentation characteristics and short-chain fatty acid (SCFA) production of purified starch sources differing in physico-chemical properties and in vitro digestion kinetics were investigated using an in vitro porcine model. Four starch sources (rapidly digestible, RD; moderately rapid digestible, MRD; moderately slow digestible, MSD; and slowly digestible, SD) were used. These starch sources were previously fed to growing pigs to determine their net portal appearance (NPA) of SCFA and glucagon-like peptide-1 (GLP-1) and fecal SCFA. Samples were incubated in a buffered mineral solution inoculated with pig feces. Gas production was measured for 72 h and fermentation kinetics were modeled. The fermented solution was analyzed for SCFA at the end of the fermentation. The SD had the greatest (P < 0.05) lag time (2.7 h) while RD to MSD did not differ (mean 2.3 h). Total gas production was greatest (P < 0.05) for MSD (239 ml/g sample) followed by RD, MRD, and SD (236, 226 and 219 ml/g sample, respectively). The fractional rate of degradation was greatest (P < 0.05) for RD (0.19/h), intermediate for MRD and MSD (0.17/h) and lowest for SD (0.11/h). Starch types did not differ (P = 0.749) in total SCFA production (5.8–6.0 mmol/g sample). Amylose content and crystallinity of starches was correlated to in vitro fermentation kinetics, total gas production, and SCFA profile. For example, fractional rate of degradation was negatively correlated with amylose content (r = −0.90, P < 0.001). Butyrate content from starch fermentation was associated with increased in vitro fractional rate of degradation and total gas production and in vivo fermentation metabolites and NPA of SCFA and GLP-1. In conclusion, physico-chemical properties and in vitro digestion kinetics of starch affect in vitro fermentation characteristics and SCFA production and are associated with NPA of SCFA and GLP-1 in pigs. Thus, the in vitro fermentation model can serve to screen starch sources to determine their fermentation characteristics in pigs.

Effects of elemental magnesium and magnesium oxide on hydrogen, methane and volatile fatty acids production in in vitro rumen batch cultures

This study aimed to examine the hypothesis that extra molecular hydrogen (H2) produced by elemental magnesium (Mg) could alter rumen fermentation and methanogenesis in in vitro batch incubation. As elevated Mg2+ may exert negative effects on rumen fermentation, magnesium oxide (MgO) was also included for comparison. Mulberry leaf and corn grain had contrast chemical composition and thus were selected as substrates for incubation. Both elemental Mg and MgO were supplemented at two levels, i.e. 0.625 and 1.25 mmol/bottle. The in vitro incubation was performed for 48 h to measure gas production (GP), H2 gas (gH2) and methane gas (gCH4) production, dissolved H2 and CH4 concentrations, and volatile fatty acids (VFA) production. Elemental Mg or MgO supplementation increased (Plinear < 0.001) Mg2+ concentration and pH in comparison to the control without supplements. There was no statistical difference (P> 0.05) in ruminal Mg2+ concentration between MgO and elemental Mg supplementation. Elemental Mg increased (P < 0.001) gH2 and gCH4 production, dissolved H2 and CH4 concentrations, in comparison to the control and MgO supplementation. Elemental Mg and MgO supplementation had lower (Plinear < 0.001) initial fractional rate of degradation, fractional rate of gas production, GP and VFA concentration than the control. Elemental Mg supplementation decreased (P < 0.05) GP and acetate molar percentage and increased (P < 0.001) propionate molar percentage, in comparison to the control and MgO supplementation. In summary, high Mg2+ concentration (> 5.5 mM) inhibits ruminal fermentation. Extra H2 produced by elemental Mg supplementation has a biological function to inhibit rumen fermentation, enhances ruminal methanogenesis and shifts the fermentation pathway from acetate to propionate production.

In Vitro and In Situ Degradation Characteristics and Rumen Fermentation Products of Moringa oleifera Harvested at Three Different Ages

Besides the beneficial agronomic properties such as drought tolerance and high biomass production, the high crude protein content of Moringa oleifera (Moringa) makes it comparable to the other high quality forages. This study aimed to evaluate whether Moringa can be an appropriate substitute for alfalfa as a ruminant feed. The study consisted of 4 treatments, namely Moringa leaves harvested at 30 (M30), 40 (M40), and 50 (M50) days after pruning, and alfalfa (Medicago sativa) hay as a control. Simultaneously, their organic matter digestibilities and fermentation characteristics were analyzed by in vitro gas production technique and rumen dry matter and protein degradability kinetics were analyzed by using the nylon bags (in situ) procedure. The results of in vitro study revealed that the potential cumulative gas production for Moringa sample harvested at 30 days after pruning was higher than that of alfalfa while the rate of gas production and the concentrations of ammonia and volatile fatty acids (VFA) in Moringa were similar to alfalfa. Moringa harvested at different times had higher in vitro organic matter digestibility (IVOMD) and metabolizable energy (ME) content as compared with alfalfa. Despite the apparent higher soluble fraction (a) and the fractional degradation rate (c) in the Moringa samples of various ages than those for alfalfa, the differences were not significant. However, in situ potentially degradable fraction (b) for DM and CP of Moringa harvested at different ages were higher than those of alfalfa (P<0.05). The in vitro fermentation and in situ degradation parameters suggested high similarities in the kinetics of gas production (i.e. a, b, and c) and DM degradation pattern among the three different cutting ages of Moringa and nutritionally they were comparable to alfalfa. In conclusion, alfalfa could be replaced with Moringa leaves in diet of ruminant animal without any adverse effect.

The effect of protected soybean groats and soybean oil as feed supplement on total gas production

The study evaluated the influence protected soybean groats and soybean oil as feed supplement on total gas production. Protected feed supplement was produced from soybean groats protected by formaldehyde and soybean oil, through two protection methods, namely saponification and microencapsulation. The experiment consisted of three treatments i.e. P0: basal diet (control); P1: basal diet + 5 % protected feed supplement and P2: basal diet + 10 % protected feed supplement. Each treatment was repeated 10 times. The observed variables were total gas production for 48 hours, gas production from fraction a and b, and degradation rate of fraction b (c value). Data were analyzed by analysis of variance. Protected soybean groats and soybean oil decreased of total gas production for 48 hours P<0,05), but did not affect gas production from fraction a, fraction b and the degradation rate of fraction b (c value). It can be concluded that the effect of supplementation of soybean groats and soybean oil decreased total gas production in the rumen and did not affect gas production from fraction a, fraction b and degradation rate of fraction b (c value) and could strategically be used to decrease methane emission from rumen fermentation in vitro.

Dietary Methionine Restriction Upregulates Endogenous H2 S via miR-328-3p: A Potential Mechanism to Improve Liver Protein Metabolism Efficiency in a Mouse Model of High-fat-diet-induced Obesity.

Dietary methionine restriction (MR) promotes multifaceted health benefits. Moreover, lower rate of protein synthesis by dietary MR is associated with life span extension. The goal of this work is to explore how dietary MR would affect protein metabolism in a mouse model of high-fat-diet-induced obesity (DIO). DIO mice (male C57BL/6) are subjected to dietary MR for 22weeks. High-throughput sequencing technology, qRT-PCR analysis, and the dual luciferase reporter assay are performed to verify that MiR-328-3p directly targets cystathionine γ-lyase (CSE) to modulate endogenous H2 S production. Moreover, indicators of endogenous H2 S, fractional synthesis rate (FSR), fractional growth rate (FGR), fractional degradation rate (FDR), and protein retention efficiency (PRE) are analyzed. MR results in an increase in endogenous H2 S to relieve oxidative stress and ER stress to improve protein homeostasis and metabolic efficiency in DIO mice. Results show that dietary MR increases endogenous H2 S production via miR-328-3p. Furthermore, these results suggest the potential involvement of endogenous H2 S on the efficiency of protein metabolism in dietary MR.

Improvement of in vitro ileal dry matter digestibility by non-starch polysaccharide degrading enzymes and phytase is associated with decreased hindgut fermentation

Efficacy of 11 non-starch polysaccharide (NSP) degrading enzymes (NSP-EZ) was evaluated when added to wheat middlings (WM) or corn distillers dried grains with solubles (cDDGS) using in vitro enzymatic digestion followed by fecal fermentation. For the in vitro enzymatic digestion, NSP-EZ and phytase (10,000 FTU/g) solution were added to WM and cDDGS samples at 20 times of the suppliers’ recommended doses. After enzymatic digestion, the hydrolyzed residues were filtered, dried, and pooled for subsequent inocubation in a buffered mineral solution with feces from pigs fed corn and soybean meal based diets. Gas production during fermentation was measured for 72 h, and its kinetics were analyzed by fitting data to an exponential model. The fermentation residues were filtered, and the supernatant was analyzed for concentration of VFA. Addition of NSP-EZ increased (P > 0.05) digestibility of dry matter (3.2%) and energy (4.2%) and solubilization of glucose and protein in WM, but not in cDDGS. During fermentation, the hydrolysis residue from WM treated with NSP-EZ had less (P < 0.05) maximal gas production, greater time to reach half asymptote, and less concentration of SCFA compared with WM control. Fermentation of WM resulted in greater (P < 0.05) disappearance of dry matter (IVFDM) than WM with added NSP-EZ. but there were no differences among cDDGS with or without NSP-EZ. The NSP-EZ containing xylanase activity had a lower (P < 0.01) fractional rates of degradation at T/2 (μT/2) and tended (P = 0.073) to have a lower IVFDM in WM compared with those without xylanase activity. In summary, exogenous NSP-EZ increase in vitro ileal digestibility of dry matter and GE in WM, but decreased fermentation of WM enzymatic residues. These results imply that fiber structure of WM may be modified by NSP-EZ, which may result in partial degradation during small intestine hydrolysis, but fiber in hydrolysis residues appears to be resistant to subsequent microbial fermentation.

In vitro investigation of the ruminal digestion kinetics of different nitrogen fractions of 15N-labelled timothy forage.

An in vitro method based on 15N-labelled forage nitrogen (N) was developed to study ruminal N metabolism of soluble N (SN), insoluble N (ISN) and neutral detergent insoluble N (NDIN) fractions of timothy forage. Timothy grass was grown on replicated experimental plots with one plot receiving 15N-labelled and the other unlabelled N fertilizer. Harvested grass was preserved as dried grass or as formic acid treated or untreated silage. The intact forages and their corresponding N fractions were incubated in buffered rumen fluid in vitro to determine degradation parameters based on the 15N fluxes between labelled feed N and ammonia N pools. A high percentage (25–38%) of 15N-labelled ammonia disappeared from ammonia N pool during the first 15 min of incubation. Microbial uptake of dried grass SN fraction was higher than of silage SN fractions. Fractional degradation rates of SN from formic acid treated silage, untreated silage and dried grass during the first 6 hours of incubation were 0.145, 0.125 and 0.115 /h, respectively. By the end of the incubation period (28 h), 69, 66 and 43%, of the SN fraction of formic acid treated silage, untreated silage and dried grass, respectively were recovered as ammonia. The percentage of ISN fractions degraded to ammonia N were 9, 34 and 27%, respectively. Based on the changes in 15N-labelled ammonia N pool in blank incubation and appearance of 15N to ammonia N pool from 15N-labelled NDIN fractions, it was estimated that a significant portion of microbial lysis occurred when incubations were carried out for longer than 20 hours. With dried grass the contribution of ammonia N for microbial N synthesis was greater than with silages. Use of 15N-labelled forages together with this in vitro method is a promising technique for determining soluble N degradation parameters, but it requires further development to be used for determining degradation parameters of insoluble N fractions and work with whole feeds.

In vitro fermentation and in situ rumen degradation kinetics of summer forage brassica plants

The aim of the present study was to assess and compare the nutrient concentration, the in vitro fermentation and the in situ rumen degradation characteristics of Brassica rapa ssp. rapa L. (turnips) and Brassica napus ssp. biennis L. (forage rape). Five varieties of each species were established in three field replicates and were organised in a randomised complete-block nested design. All varieties were harvested and further analysed for chemical composition, in vitro gas-production kinetics, volatile fatty acid (VFA) production and in situ degradation kinetics of dry matter (DM) and crude protein. Turnips showed higher ash, total sugars, raffinose, sucrose, glucose and fructose concentrations (P &amp;lt; 0.001) than did forage rape. Turnip varieties differed in their sucrose, glucose, fructose and total soluble sugar concentration (P &amp;lt; 0.001), whereas rape varieties differed in their neutral detergent fibre concentration (P = 0.004) and digestible organic matter on a DM basis (P &amp;lt; 0.01). Regarding DM-degradation parameters, turnips had a higher soluble fraction ‘a’ (P &amp;lt; 0.01) and a lower insoluble, but potentially degradable fraction ‘b’ (P &amp;lt; 0.01) than did rape, but the fractional degradation rate ‘c’ (0.18/h) was similar to that of rape. Rates of gas production were slightly higher (P = 0.018) for turnip than for rape. No effects for brassica species nor for varieties within species were detected (P &amp;gt; 0.05) for total in vitro VFA production, as well as for the relative proportions of acetate, propionate, butyrate, branch chained VFA and the actetate:propionate ratio. Our study showed that most of the differences that were observed in terms of chemical composition and degradation kinetics did not result in differences in in vitro fermentation products.

Protein value and degradation characteristics of pulp fibre fractions from screw pressed grass, clover, and lucerne

Biorefinery of grassland plants may enable the production of feed for both ruminants and monogastrics at the same time. The pulp fibre fraction from twin-screw processed white clover, red clover, lucerne, and perennial ryegrass, is a major side-stream commonly considered of low value. However, it maintains a crude protein (CP) fraction of which a high proportion is expected to be fibre-associated. The pulp is expected to be suitable as forage for ruminants but knowledge of the feed value is limited.The objectives of this study were to assess the protein degradation in the rumen and the protein value of pulp compared to the original plant material, and to study the protein distribution among fibre fractions in order to evaluate the pulp as a source of forage for dairy cows.The ash concentration in the pulp was 51.1–72.3 g/kg DM compared to 86.3–104 g/kg DM in the original plant, while the in vitro digestible organic matter (DOM) in dry matter (DM) did not decrease significantly in pulp (532–689 g/kg DM) compared to plant (564–694 g/kg DM). Neutral detergent fibre (aNDF) concentration was higher in pulp (529–694 g/kg DM) than in original plant (342–503 g/kg DM), while the CP concentration of the aNDF from pulp (77.8–186 g/kg aNDF) did not differ from the concentration found in the plant aNDF (74.7–137 g/kg aNDF). Furthermore, the total amino acid (AA) concentration increased in pulp (825 g/kg CP) compared to original plant (768 g/kg CP), and the individual concentration of all essential AA in DM increased.The in situ rumen degradation of CP showed that the potentially degradable fraction was not different between plant (889–953 g/kg) and pulp (817–939 g/kg), although the fractional rate of degradation was lower in the pulp (0.093–0.109 h−1) than in the plant (0.113–0.192 h−1). Thus effective degradability (ED) of CP was lower in pulp (579–647 g/kg) than in plant (657–786 g/kg) increasing rumen escape protein (REP). The intestinal digestibility of REP was similar, thus a higher proportion of the pulp CP (225–256 g/kg) was digested in the intestine compared to plant CP (125–190 g/kg). The indigestible neutral detergent fibre (INDF) proportion of aNDF was not different between plant (88.1–422 g/kg aNDF) and pulp (85.3–460 g/kg aNDF).This study demonstrated that pulp from twin-screw pressing of white clover, red clover, lucerne, and perennial ryegrass has a protein concentration and value for ruminants, which is similar to the original plant material.