VFA Concentration Research Articles

Modeling an acid-phase digester in BioWin with parameter optimization from site data

Organic acid digesters are reactors of growing interest for municipal nutrient recovery technologies, but the industry standard BioWin modeling software does not accurately predict their performance. A BioWin configuration using default parameters will over-predict volatile fatty acid production in an acid digester, yielding an unrealistically low pH. We have characterized the effects of parameters for local pH inhibition thresholds, growth and decay kinetics, and hydraulic residence times to successfully facilitate more accurate modeling of acid phase digestion reactors in BioWin. These changes show improvements in a range of treatment train models without affecting accuracy in other reactors. Results were calibrated against a municipal acid phase digester to accurately predict pH, VFA concentration, and gas production. In particular, an acid digester with a measured suspension pH of 5.14 was predicted by BioWin using default parameters to exist at pH 4.35 with highly sensitive biogas methane content, but our parameter changes were able to correct the predicted suspension pH and VFA concentrations over a range of values. We also demonstrate that several intuitive or traditional parameters a BioWin user may attempt, such as growth and fermentation kinetics, do not yield meaningful results. Refinements incorporated into BioWin should allow future operators to easily model acid digesters for their specific treatment trains or allow users to predict changes while testing new wastewater treatment technologies.

Effects of Black Soldier Fly oil and calcium soap supplementation on rumen fermentability of Garut Sheep

Fat is a source of energy for livestock, with low heat metabolic, but dietary fat had negative impact for rumen fermentation. Calcium soap can protect fat for ruminant. This study aimed to examine the characteristics of rumen fermentation in Garut sheep fed with suplements of BSF (Hermetia illucens) oil and BSF Calcium soap. This research used fifteen male Garut sheep with an average body weight of 29.90 ± 3.71 kg. This research used randomized block design consisting of three treatments and five replicates. The treatments were diet without supplementation BSF oil or Calcium soap (P1), diet with BSF oil suplementation 4% (P2) and diet with BSF Calcium soap suplementation 4% (P3). Data were analyzed using ANOVA and further test with Duncan test. The analysis showed that the rumen pH value, ammonia concentration, and protozoa population in the rumen were not affected by the treatments. Concentration of VFA and population of rumen bacteria were significantly (P<0.05) affected by the treatments. The total VFA concentration of P3 was significantly higher (P<0.05) than P1 and P2. Rumen bacteria population of P3 was significantly higher (P<0.05) than P1 and or P2. It can be concluded that supplementation of BSF Calcium soap improve rumen fermentation indicated by higher VFA concentration and bacteria population in the rumen.

Rumen microbiome response to sustained release mineral bolus supplement with low- and high-quality forages

IntroductionLimited forage quantity and quality are challenges faced in livestock production systems in semi-arid rangelands of the western United States, particularly when livestock face stressors such as cold weather or have increased nutritional requirements such as during pregnancy and lactation. To meet livestock nutrient requirements, producers frequently provide supplemental nutrition, however there is limited knowledge regarding the effects of these practices on the rumen microbiome in these environments.MethodsA study was conducted to evaluate changes in the rumen microbiome in response to high- and low- quality forage with sustained release mineral boluses. The study consisted of 16 ruminally-cannulated 2–3-year-old black angus cows fed high quality grass alfalfa hay or low-quality grass hay with a 90 or 180 day sustained release mineral bolus. Rumen samples were collected pre-feeding and 8 hours post feeding and bacterial 16S rRNA gene amplicons were sequenced from the rumen fluid.ResultsAlpha diversity as measured by Shannon’s diversity index decreased significantly over time (p&amp;lt;0.01) and averaged 5.6 pre-feeding and 5.4 post- feeding and was not significantly different between high- and low-quality forages or between mineral bolus types (p&amp;gt;0.05). Principal coordinates analysis (PCoA) of the Bray-Curtis dissimilarity matrix showed distinct grouping by feed quality and time but not by mineral bolus type. Bacteroidetes and Firmicutes were the dominant phyla in all treatments and significant increases (p&amp;lt;0.05) in the relative abundance of the family Lachnospiraceae and the genus Prevotella were observed in high quality forage diets. Rumen VFA and NH3-N concentrations were also strongly associated with the high-quality forage diet. Predictive functional profiling indicated that functions associated with methanogenesis were negatively correlated with feed quality.DiscussionThe results of this study suggest that mineral bolus type is unlikely to affect rumen bacterial community structure or function while forage quality can significantly alter community structure and predicted functions associated with methanogenesis and VFA production.

Polyclonal antibodies inhibit growth of key cellulolytic rumen bacterial species.

Antibodies targeting specific bacterial species could allow for modification of the rumen microbial population to enhance rumen fermentation. However, there is limited knowledge of targeted antibody effects on rumen bacteria. Therefore, our objective was to develop efficacious polyclonal antibodies to inhibit the growth of targeted cellulolytic bacteria from the rumen. Egg-derived, polyclonal antibodies were developed against pure cultures of Ruminococcus albus 7 (anti-RA7), Ruminococcus albus 8 (anti-RA8), and Fibrobacter succinogenes S85 (anti-FS85). Antibodies were added to a cellobiose-containing growth medium for each of the three targeted species. Antibody efficacy was determined via inoculation time (0 h and 4 h) and dose response. Antibody doses included: 0 (CON), 1.3 × 10-4 (LO), 0.013 (MD), and 1.3 (HI) mg antibody per ml of medium. Each targeted species inoculated at 0 h with HI of their respective antibody had decreased (P < 0.01) final optical density and total acetate concentration after a 52 h growth period when compared with CON or LO. Live/dead stains of R. albus 7 and F. succinogenes S85 dosed at 0 h with HI of their respective antibody indicated a decrease (≥ 96%; P < 0.05) in live bacterial cells during the mid-log phase compared with CON or LO. Addition of HI of anti-FS85 at 0 h in F. succinogenes S85 cultures reduced (P < 0.01) total substrate disappearance over 52 h by at least 48% when compared with CON or LO. Cross-reactivity was assessed by adding HI at 0 h to non-targeted bacterial species. Addition of anti-RA8 or anti-RA7 to F. succinogenes S85 cultures did not affect (P ≥ 0.45) total acetate accumulation after 52 h incubation, indicating that antibodies have less of an inhibitory effect on non-target strains. Addition of anti-FS85 to non-cellulolytic strains did not affect (P ≥ 0.89) OD, substrate disappearance, or total VFA concentrations, providing further evidence of specificity against fiber-degrading bacteria. Western blotting with anti-FS85 indicated selective binding to F. succinogenes S85 proteins. Identification by LC-MS/MS of 8 selected protein spots indicated 7 were outer membrane proteins. Overall, polyclonal antibodies were more efficacious at inhibiting the growth of targeted cellulolytic bacteria than non-targeted bacteria. Validated polyclonal antibodies could serve as an effective approach to modify rumen bacterial populations.

Pengaruh Substitusi Silase Rumput Kume dengan Fodder Jagung Hidroponik Terhadap Konsumsi dan Kecernaan Karbohidrat, Konsentrasi Vollatile Fatty Acid dan Kadar Glukosa Darah Kambing Kacang Jantan

This aim of this research is to determine the effect of substitution of sorghum plumosum silage with hydroponic corn fodder on carbohydrate intake and digestibility, VFA concentration and blood glucose levels of male kacang goats. This study used 3 male goats under one year of age and body weight between 13,5-17,1 kg. The research method used latin square design with 3 periods and 3 treatments, consisting of FCG0: 70% kume grass silage + 30% concentrate, FCG1: 35% kume grass silage + 35% corn fodder + 30% concentrate, FCG2: 20% kume grass silage + 50% corn fodder + 30% concentrate. The parameters analyzed were carbohydrate intake, carbohydrate digestibility, VFA concentration and blood glucose levels. The result as follows that: then means carbohydrates consumption (g/h/d) FCG0: 245,99069±161,85, FCG1: 185,55441±61,14, FCG2: 260,90534±70,35. Carbohydrates digestibility (%) FCG0: 60,17990±16,93, FCG1: 66,39760±4,04, FCG2: 82,29166±5,45. VFA concentration (mM) FCG0: 101,386±34,25, FCG1: 124,043±17,85, FCG2: 98,778±14,80. Blood glucose levels (mg/dl) FCG0: 59,66333±4,46, FCG1: 59,80667±13,59, FCG2: 62,86667±3,16. The analysis results showed that the treatments had no significant effect (P&gt;0,05) on carbohydrate intake and digestibility, VFA concentration and blood glucose levels. The conclusion of this study is that feed 20% of sorghum plumosum silage with 50% of hydroponic corn fodder give the same response with 70% of sorghum plumosum silage of male kacang goats.

Effect of substituting grass-clover silage with maize silage for dairy cows on nutrient digestibility, rumen metabolism, enteric methane emission and total carbon footprint

The aim of this experiment was to determine the optimal ratio between maize silage and grass-clover silage in lactating dairy cow diets. The evaluation was based on nutrient digestibility, rumen metabolism and total carbon footprint (CF). Carbon footprint included enteric methane emission and CF from feed production, transportation, processing, and C sequestration in the soil, based on a Life Cycle Assessment (LCA) approach. Four diets varying in proportions of grass-clover silage and maize silage (100:0, 67:33, 33:67, and 0:100 on dry matter (DM) basis, respectively) were fed ad libitum to 4 lactating Holstein cows (a fifth cow was involved later in the study) fitted with ruminal, duodenal, and ileal canulae in a 4 × 4 Latin square design. Nutrient digestibility was measured using chromium oxide and titanium oxide as flow markers, and methane and CO2 emissions were measured in open-circuit respiration chambers on 5 consecutive days for each cow in each period. Data were analyzed with treatment and period as fixed effects and cow as random effect. DM intake (DMI) increased linearly (P = 0.01) with increased proportion of maize silage in the feed ration. Under the conditions in the present study, diets had only minor effects on digestibility of nutrients and there was no influence on rumen pH. Total VFA concentration decreased linearly with increased level of maize silage, but there were only minor effects on molar proportions of VFAs in the rumen. However, there was a linear increase in duodenal flow of microbial DM with increasing level of maize silage. The cows produced 30.7, 29.4. 28.4, and 26.2 L of methane/kg of DMI on diets 100:0, 66:33, 33:66, and 0:100, respectively (P = 0.02 for linear effect), which is equivalent to a 15% decrease, when all grass-clover silage was replaced by maize silage. Despite the significant reduction in enteric methane emission with increased proportion of maize silage, only a 4% decrease in total CF per kg DMI was found, when including CF from feed production, transportation, processing, manure, energy use and C sequestration in the soil, when using a LCA approach. If direct Land Use Change (LUC) or indirect LUC was included in estimation of CF, the reduction in CF when replacing all grass-clover silage was also 4–6%. However, the total CF was highly dependent on assumptions related to yield of grass-clover and maize.

Layer Inoculation as a New Technology to Resist Volatile Fatty Acid Inhibition during Solid-State Anaerobic Digestion: Methane Yield Performance and Microbial Responses

Solid-state anaerobic digestion is easily inhibited by high volatile fatty acid induced by high total solids, although it is a promising technology. Previous studies on volatile fatty acid inhibition mainly focused on total solid content, co-digestion substrates, and external additives. The present study proposed a new inoculation method named layer inoculation and compared it to premixing inoculation in the solid-state anaerobic digestion of pig manure and maize straw. The results showed that the cumulative CH4 yields from layer inoculation (211.5 mL/g-VS) were 5.64 times more than premixing inoculation (37.5 mL/g-VS) under a low inoculation ratio (25%), with the values of total volatile fatty acid being greater than 30.0 mg/g. The concentrations of total VFAs and acetic acid from layer inoculation decreased dramatically during days 18–43. Layer inoculation also showed wider specific methane yield peaks and shorter startup times than premixing inoculation. Methanosphaerula and Methanothrix were the most dominant genera, while the genus Methanosphaerula did not correlate with volatile fatty acids, pH, or total ammonia nitrogen. The hydrogenotrophic methanogen pathway was predominant during solid-state anaerobic digestion; the shift from hydrogenotrophic to acetoclastic occurred in premixing inoculation, and it was stable in layer inoculation (61.20–68.88%). Overall, layer inoculation can effectively enhance methane production under high volatile fatty acid concentrations compared with premixing inoculation.

Deeper insights into the synergy of material transformation, microbial network, and energy balance during pilot thermophilic and mesophilic dry anaerobic digestion systems

The present study investigated the synergistic characteristics between abiotic and biotic transformation with a view to improving the methane production efficiency of thermophilic and mesophilic sequencing batch dry anaerobic digestion (SBD-AD). The pilot scale experiment consisted of a lignocellulosic material based on a mixture of corn straw and cow dung. A leachate bed reactor was used for an AD cycle of 40 days. Several distinct differences are reflected in biogas (methane) production and VFA concentration and composition. A combination of first-order hydrolysis and a modified Gompertz model determined that the holocellulose (cellulose + hemicellulose) and maximum methanogenic efficiency at thermophilic temperatures were increased by 112.03 % and 90.09 %, respectively. Additionally, the methane production peak was extended by 3–5 days in comparison with that at mesophilic temperatures. The microbial community exhibited vastly different functional network relationships under the two temperature conditions (P < 0.05). The data indicate that Clostridales and Methanobacteria had preferable synergistic effects and that the metabolism of hydrophilic methanogens is necessary for the conversion of VFA to methane during thermophilic SBD-AD. The effect of mesophilic conditions on Clostridales was relative weakened, and acetophilic methanogens were mainly present. Moreover, simulation of the full-chain and operational strategy of SBD-AD engineering resulted in a decrease in heat energy consumption of 21.4–64.3 % at thermophilic temperatures and 30.0–90.0 % at mesophilic temperatures from winter to summer. Furthermore, the total net energy production of thermophilic SBD-AD was increased by 105.2 % in comparison with that at mesophilic temperatures, demonstrating strengthened energy recovery. Overall, raising the SBD-AD temperature to thermophilic levels has considerable application value for improving the treatment capacity of agricultural lignocellulosic waste.

In Vivo Digestibility and In Vitro Fermentation of High Dietary Fiber Forages in Growing Pigs’ Diets

The pig farming industry is constantly challenged to seek low-cost ingredients that fulfill animal requirements. In this study, two summer forage brassica meals were assessed as sources of dietary fiber in growing pigs by in vivo digestibility and in vitro fermentation experiments. The control diet included corn, soybean meal, and wheat middlings. The experimental diets replaced wheat middlings (15%) with turnip (Brassica rapa) roots or fodder rape (Brassica napus) whole plant meal, respectively. All diets were elaborated to be iso-nitrogenous and iso-energetic. The turnip diet had a greater digestibility rate for gross energy (p = 0.020). The ash digestibility was greater for the rape diet and intermediate for the turnip diet, with the lowest value for the control diet (p = 0.003). When incubating pure brassica forages, only gas production at 72 h was greater for the turnip than rape diet (p = 0.04). No differences (p &gt; 0.05) in the in vitro gas production parameters were observed among the diets. The pure fermentation of turnip increased the VFA concentration and propionate molar proportion, whereas acetate was reduced (p &lt; 0.05), which resulted in a trend towards a greater propionate molar proportion with the inclusion of turnip in the diet (p = 0.067). The inclusion of 15% of turnip meal increased the in vivo energy digestibility and tended to modify the fermentation parameters, increasing the molar proportion of propionate, whereas the inclusion of whole plant fodder rape did not affect the in vivo digestibility or in vitro fermentation compared with the control diet.

Comparation of moist heating and formaldehyde protein protection methods and their impact on dairy ration fermentability and digestibility

Improving protein efficiency has become the main target in dairy farming. The feeding strategy for high-producing cows is directed by optimizing non-protein nitrogen utilization while maintaining post-ruminal digested bypass protein. Soybean and soybean meal are protein sources with high biological value but are highly degradable, so they must be protected. This study aimed to compare the effect of moist heating and formaldehyde treatments as a method for protecting protein to increase rumen bypass protein. Parameters observed include fermentation profile (rumen pH, NH3, total VFA, protozoa, and total bacteria population) and nutrient digestibility. Treatments tested were an unprotected diet as control (C1), moist heating protected protein (C2), and formaldehyde protected protein (C3). Data were subjected to ANOVA using Randomized Block Design followed by orthogonal contrasts. The results showed that both moist heating and formaldehyde treatments (C2 and C3) reduced NH3 and total VFA concentration (p<0.05) without affecting rumen pH, protozoa, and total bacteria count (p>0.05). Dry matter and organic matter did not affect by the treatments. In conclusion, both moist heating and formaldehyde methods could be used to protect feed protein and improve bypass protein in the dairy ration.

Finisher lamb growth and rumen fermentation responses to the plane of nutrition and naturally occurring coccidiosis.

The objective of the present study was to investigate the interaction of plane of nutrition and naturally occurring coccidiosis on finisher lamb growth performance, FAMACHA score, and rumen volatile fatty acid profile. The study included 30 Suffolk, Dorset or Suffolk x Dorset lambs and were divided into 2 groups based on their initial body weight and assigned to 2 feeding groups differing in dietary energy intake to create lambs representing divergent growth curves due to differing nutritional management. Lambs with naturally occurring coccidiosis and healthy lambs were present in both feeding groups making a 2 × 2 factorial arrangement of treatments, (a) high plane of nutrition (HPN) lambs with no clinical coccidiosis diagnosis (HPNH), (b) HPN lambs with clinical coccidiosis (HPNC), (c) low plane of nutrition (LPN) lambs with no clinical coccidiosis diagnosis (LPNH), (d) LPN lambs with clinical coccidiosis (LPNC). Body weight and FAMACHA scores were recorded once every 2 weeks. On d 65 of feeding, lambs were slaughtered, and rumen fluid samples were collected and analyzed for volatile fatty acid concentrations. All response variables were analyzed statistically using a linear mixed effects model with fixed effects for plane of nutrition, health status, and a random effect for initial body weight nested within the pen. The total and average weight gain were not associated with planes of nutrition, health status, or the interaction. Health status had an impact on FAMACHA© score (P = 0.047) and concentration of isobutyrate (P = 0.037) and tended to affect total VFA (P = 0.085) and acetate (P = 0.071) concentrations. The interaction between the plane of nutrition and the health status tended to affect butyrate concentration (P = 0.058). These data support the conclusion that coccidiosis infection impacted on rumen fermentation in a manner independent of the plane of nutrition; however, the translation of these rumen level impacts did not translate to the production responses.

TEA SAPONIN MODULATES IN VITRO RUMEN FERMENTATION PROFILE AND REDUCES METHANE PRODUCTION: A META-ANALYSIS

Saponins are secondary plant metabolites binding hydrophobic non-sugar components that can reduce ruminant methane (CH4) production. Previous studies revealed that tea saponin is one of the common sources of saponins used to reduce enteric CH4 production. However, the effect of different levels of dietary tea saponin on rumen fermentation remains inconclusive. This study aimed to investigate the effect of tea saponin on in vitro rumen fermentation and methane production through a meta-analysis approach. A total of 6 articles were selected and included in the meta-analysis database, continued by the statistical analysis using SAS software through mixed model formula. The results showed that tea saponin levels lowered in vitro organic matter degradability (IVOMD) and in vitro dried matter degradability (IVDMD; P=0.01) by a linear response. Furthermore, increased tea saponin levels in the diet reduced enteric CH4 emission expressed as CH4/DM substrate and CH4/IVOMD by a quadratic (P=0.01) and a linear response (P=0.04), respectively. Increased tea saponin levels also tended to decrease gas production linearly (P=0.08). Tea saponins inclusion also decreased pH levels linearly (P=0.04) but increased NH3 quadratically (P=0.01). Moreover, total VFA concentration in the rumen also raised quadratically, followed by the increased acetate (C2) and propionate (C3) proportion by a linear response (P&lt;0.05). As a result, the C2/C3 ratio was decreased in a linear response (P=0.01) by the increased tea saponin levels, where the protozoa population was also diminished by a quadratic response (P=0.01). In conclusion, tea saponin levels directly reduced enteric CH4 production by diminishing microbial populations.

Optimization and modelling of volatile fatty acid generation in a leachate bed reactor for utilization in microbial fuel cells

AbstractVolatile fatty acid (VFA)‐rich leachate generated from acidogenesis of kitchen waste in a leach bed reactor (LBR) was utilized in an earthen microbial fuel cell (EMFC) to generate electricity. Effects of organic loading rate (OLR, 5–10 g VS/L·day) and pH (5–7) on LBR enumerated optimized parameters of OLR (10 g VS/L·day) and pH (5.74) to obtain total VFA (TVFA) of 7.7 ± 0.3 g/L in the leachate, with maximum contribution from acetic acid. Leachate obtained from the LBR was fed to the EMFC with varying OLR (2–7 kg COD/m3·day). The highest power density of 0.76 W/m3 (at OLR 7 kg COD/m3·day) was obtained with higher VFA content in the leachate. A neural network based on the Levenberg–Marquard function effectively predicted chemical oxygen demand and TVFA removal. This study establishes LBR as a techno‐economic method to obtain useful substrate for EMFC. Furthermore, the response modelling of EMFC demonstrates the potential of utilizing machine learning in biological treatment.

Effect of replacing cottonseed meal with canola meal on growth performance, blood metabolites, thyroid function, and ruminal parameters of growing lambs

The objective was to clarify the impact of replacing cottonseed meal with canola meal (CM) on growth performance, blood metabolites, thyroxin function, and ruminal parameters of growing lambs. Twenty-four growing Barki male lambs (4–5 months of age) were assigned randomly into four equal groups (6 lambs each). Four dietary treatments were the control group with 0% CM (CON) and three experimental groups where CM replaced 25% (CN1), 50% (CN2), and 75% (CN3) of cottonseed meal. There were no dietary effects (P > 0.05) on the lambs’ feed intake, average daily gain, and feed conversion ratio of the lambs. The dietary CM linearly decreased the concentrations of serum total proteins (P = 0.003), albumin (P = 0.010), globulin (P = 0.011), AST (P = 0.041), and urea (P = 0.001) in growing lambs. The levels of ALT and creatinine, however, were not significantly affected by dietary treatments (P > 0.05). Furthermore, serum triiodothyronine, thyroxine, and electrolyte concentrations were similar (P > 0.05) in different dietary groups. Dietary treatments significantly affected the values of ruminal pH and ammonia at 0 h (P = 0.003 and 0.048, respectively) and 3 h (P = 0.033 and P = 0.006, respectively) postfeeding. The CN3 group showed significantly higher concentrations of ruminal ammonia at 0 and 3 h postfeeding. Furthermore, dietary CM (CN3) significantly reduced the ruminal pH values at 0 and 3 h postfeeding. Meanwhile, dietary treatments did not affect the concentration of total VFAs in the ruminal fluid. In conclusion, CM can replace the cottonseed meal (up to 75%) in lamb diets without compromising their growth performance, thyroid function, and ruminal fermentation parameters.

Effects of different concentrations of butyrate on microbial community construction and metabolic pathways in anaerobic digestion

Investigating the effect of butyric acid concentration on anaerobic digestion systems in complex systems is important for the efficient degradation of butyric acid and improving the efficiency of anaerobic digestion. In this study, different loadings of butyric acid with 2.8, 3.2, and 3.6 g/(L·d) were added to the anaerobic reactor. At a high organic loading rate of 3.6 g/(L·d), methane was efficiently produced with VBP (Volumetric Biogas Production) of 1.50 L/(L·d) and biogas content between 65% and 75%. VFAs concentration remained below 2000 mg/L. Metagenome sequencing revealed changes in the functional flora within different stages. Methanosarcina, Syntrophomonas, and Lentimicrobium were the main and functional microorganisms. That the relative abundance of methanogens exceeded 35% and methanogenic metabolic pathways were increased indicated the methanogenic capacity of the system significantly improved. The presence of a large number of hydrolytic acid-producing bacteria also indicated the importance of the hydrolytic acid-producing stage in the system.

Effects of substitution of millet straw for corn silage and alfalfa hay on lactation performance, ruminal fermentation, and blood metabolites in late-lactation Holstein dairy cows

The study was conducted to evaluate the effect of replacing dietary corn silage (CS) and alfalfa hay (AH) with millet straw (MS) on the production performance and the ruminal fermentation patterns of Holstein cows in late lactation. For this purpose, forty-eight multiparous Holstein dairy cows blocked by milk yield (32 ± 3.2 kg/d) and days in milk (179 ± 19 d) were randomly allocated to one of four treatments. The diets were formulated with a forage-to-concentrate ratio of 48:52 [dry matter (DM) basis] and contained the same concentrate mixtures, with different forage sources (on a DM basis): (1) Control (60% CS, 40% AH, and 0% MS; on 100% roughage); (2) LMS (54% CS, 36% AH, and 10% MS), (3) MMS (48% CS, 32% AH, and 20% MS), and (4) HMS (42% CS, 28% AH, and 30% MS). The dry matter intake and milk yield were lower in the HMS diet than those in the Control, LMS, and MMS diets (P < 0.01), whereas there was no difference in the Control, LMS, and MMS diets. Compared with the Control diet, 4% FCM, milk protein yield, and N conversion ratio decreased in the MMS and HMS diets (P < 0.01), whereas no difference between the Control and LMS diets was found. Besides, cows fed the HMS diet had lower milk fat yield, lactose percentage, and feed efficiency than those in the Control and LMS diets (P < 0.05), with no difference between the Control, LMS, and MMS diets. The percentage of milk fat and protein was not affected by the diets. Compared with the Control diet, the total VFA concentration was decreased, whereas the ammonia-N concentration was increased in the HMS diet (P < 0.05), with no difference between the Control, LMS, and MMS diets. The molar proportion of acetate and the ratio of acetate to propionate were lower (P < 0.01), while the molar proportion of propionate was higher in the Control diet than that in the MMS and HMS diets (P < 0.01), with no difference between the LMS and MMS diets. Compared with the Control, the apparent digestibility of DM, CP, NDF, and ADF was decreased, while the blood urea nitrogen concentration was increased in the HMS diet (P < 0.05), with no differences in the Control, LMS, and MMS diets. Thus, it was concluded that it is feasible to use MS as a fiber source for late-lactation dairy cows. However, considering the milk production performance and the feed digestibility, the replacement of CS and AH with MS should not exceed 20% of the roughage.

Effects of different starch diets on growth performance, intestinal health andfaecal microbiota of growing pigs.

This experiment was conducted to investigate the effects of different starch source diets on growth performance, intestinal health, and, microbiota of growing pigs. Eighteen healthy "Duroc × Landrace × Yorkshire" pigs (50 ± 0.61 kg, Castrated boar) were randomly divided into three groups with six replicates and one pig per replicate. The pigs in the three treatments were fed diets prepared with cassava flour (CF), rice bran (RB)andsorghum flour (SF), respectively, and the nutritional levels of the three treatments were the same. The experiment lasted for 28 days. The results showed that pigs in the RB group had significantly increased average daily gain (ADG, p < 0.05) compared with pigs in CF and SF groups. Compared with pigs in the CF group, the final body weight (FBW) of growing pigs in the RB group was increased and the ratio of feed to gain (F: G) was decreased (p < 0.05). There was no significant difference between FBW and F: G between the SF group and the other two groups. Compared with the CF group, the RB group significantly increased the jejunum amylase activity (p < 0.05), and there was no significant difference between the SF group and the other two groups. Compared with growing pigs in the CF group and SF group, the duodenal villus height and villus height/crypt depth ratio of growing pigs in the RB group were significantly increased (p < 0.05). The concentrations of acetic acid, propionic acid, and total VFA in the colon and caecum of piglets in the SF group were significantly increased (p < 0.05) compared to piglets in CF and RB groups, and there was no significant difference between the CF group and RB group. Compared with the RB group, caecal butyric acid concentration was significantly increased in SF and CF groups (p < 0.05). Seven dominant phyla were identified at the phylum level, among which Firmicutes, Bacteroidotaand Spirochaetota were dominant phyla, accounting for 74.18%, 14.87% and6.56% of the RB grouprespectively. Cassava flour group accounted for 80.22%, 9.64% and3.71%; Accounting for 65.33%, 17.34% and13.07% of the SF group. Through the comparative analysis of microbial differences among the treatment groups, it was found that at the phylum level, compared with the SF group, the abundance of Synergistota in the diet of the CF group and the diet of the RB group was significantly increased (p < 0.05). The abundance decreased significantly (p < 0.05). The quantity of Desulfobacterota in the RB group was significantly higher than that in the CF group (p < 0.05). In conclusion, compared with sorghum starch and cassava starch, RB starch can improve the activity of digestive enzymes and villus height in the small intestine of growing pigs and promote the growth of pigs by protecting the intestinal health of growing pigs.

Fast Protein and Metabolites (Nucleotides and Nucleosides) Liquid Chromatography Technique and Chemical Sensor for the Assessment of Fish and Meat Freshness

Fast protein and metabolite liquid chromatography (FPLMC) was introduced years ago to enable the easy separation of high-molecular compounds such as proteins from small molecules and the identification of the low-molecular substances. In this paper, the method is applied for the rapid evaluation of freshness and monitoring the aging of animal meat and fish. A novel chromatographic sensor was developed with a deep UV LED-based photometric detection unit (255–265 nm), an original flow cuvette and registration scheme; the processing of a chromatogram with the sensor takes approximately 15 min. Strict isochronism between the elution of ATP metabolites, mainly hypoxanthine (Hx) and inosine monophosphate (IMP), and the time of maturation of meat or fish, was discovered. A new freshness index H* = [Hx]/[IMP] was introduced, which is proportional to the instrumental delay time in the FPMLC chromatograms: the H* index &lt; 0.5 indicates the presence of inosine monophosphate (IMP) and the high quality of the meat or fish. Reasonably strong correlations were revealed between data obtained by FPMLC and total volatile basic nitrogen TVB-N (for fish) or volatile fatty acids VFA (for meat) content. Moreover, putative nucleotide salvage and an increase in the concentration of IMP were observed in fish after heat treatment using the FPMLC sensor and NMR technique.

GPR120 Gene expression and activity in subcutaneous and intramuscular adipose tissues of Angus crossbred steers.

We hypothesized that media long-chain fatty acids (LCFA) would more greatly depress cyclic adenosine monophosphate (cAMP), glycerol, and free fatty acid (FFA) concentrations in subcutaneous (s.c.) adipose tissue than in intramuscular (i.m.) adipose tissue via G protein-coupled receptor 120 (GPR120). The GPR120 receptor binds to LCFA, which reduces cAMP production, thereby causing a depression in lipolysis. Fresh ex vivo explants of s.c. and i.m. adipose tissue from the fifth to eighth longissimus thoracic rib muscle section of 8, 22-mo-old Angus crossbred steers were transferred immediately to 6-well culture plates containing 3 mL of Krebs-Henseleit buffer/Hepes/5 mM glucose. Samples were preincubated with 0.5 mM theophylline plus 10 μM forskolin for 30 min, after which increasing concentrations of acetate or propionate (volatile fatty acids, VFA) (0, 1, 5, and 10 mM) in the absence or presence of 100 µM oleate (18:1n-9) or 100 μM palmitate (16:0) (LCFA) were added to the incubation media and incubated an additional 30 min. Main effects of adipose tissue depot (i.m. vs. s.c) and VFA (acetate vs. propionate) for adipose tissue concentrations of forskolin-stimulated cAMP were P = 0.747 and P = 0.106, respectively. The addition of LCFA to the media depressed adipose tissue concentrations of cAMP (P = 0.006) (LCFA main effects). The Tissue × VFA × LCFA interaction was not significant for any dependent variable (P ≥ 0.872). Therefore, concentrations of cAMP, glycerol, and FFA were analyzed separately for i.m. and s.c. adipose tissue by split-plot analysis. Concentrations of cAMP, glycerol, or FFA in i.m. and s.c. adipose tissue were not affected by increasing concentrations of VFA (P ≥ 0.497). Media LCFA had no effect on i.m. adipose tissue cAMP (P = 0.570) or glycerol (P = 0.470) but depressed i.m. adipose tissue FFA (P < 0.001). In s.c. adipose tissue, LCFA decreased concentrations of cAMP (P = 0.042) and glycerol (P = 0.038), but increased FFA concentration (P = 0.026). Expression of GPR120 (P = 0.804) and stearoyl-CoA desaturase (P = 0.538) was not different between s.c. adipose tissue and i.m. adipose tissue. The binding of VFA to the GPR43 receptor depresses cAMP production, thereby attenuating lipolysis, but GPR43 mRNA was undetectable in those adipose tissue samples. These results provide evidence for functional GPR120 receptors in s.c. adipose tissue but question the role of GPR43 in the accumulation of adipose tissue lipids in growing steers.

Effects of adding ruminal propionate on dry matter intake and glucose metabolism in steers fed a finishing ration.

The objective of this experiment was to determine if supplying additional propionate to the rumen alters dry matter intake (DMI), feeding behavior, glucose metabolism, and rumen fluid metabolites in steers fed a finishing diet. Ruminally cannulated steers (n = 6) were fed a finishing diet ad libitum. Steers were randomly assigned to one of three treatments in a 3 × 6 Latin rectangle design with three 15 d periods. Treatments of no Ca propionate (Control), 100 g/d (Low), or 300 g/d (High) were ruminally dosed twice daily. Individual intake was measured using an Insentec feeding system. Pre-feeding blood samples were collected on day 7 and rumen fluid samples were collected on day 13. An intravenous glucose tolerance test (IVGTT) was conducted on day 14 and liver biopsies were collected on day 15. Liver samples were analyzed for expression of genes involved in gluconeogenesis. Data were analyzed using a mixed model with period, treatment, day, and their interaction included, with day and minute within period as a repeated measure and steer as a random effect. Meal size (P = 0.049), meal frequency (P = 0.046), and DMI (P < 0.001) were decreased in High steers. Day 7 plasma glucose (P = 0.23) and lactate (P = 0.47) were not affected by treatment, but insulin was decreased (P = 0.008) and non-esterified fatty acids were increased (P = 0.044) in the High treatment compared with the Control. Rumen fluid lactate was decreased (P = 0.015) in the High treatment compared with the Low treatment. Total VFA concentrations did not differ (P = 0.88) between treatments. There was treatment × time interaction for proportions of acetate and propionate (P < 0.001) and the acetate:propionate ratio (P = 0.005). The effect on acetate was due to a decrease in the High treatment 2 h after dosing the treatment. Propionate proportions were greater in the High treatment than the Control at all time points and differed from the Low except at 0 h. Propionate treatments had no major effects on the glucose and insulin parameters observed in the IVGTT other than a tendency (P = 0.09) for an increased insulin time to peak. These data indicate that exogenous propionate decreases DMI but the decrease in propionate from fermentation due to reduced DMI might negate the supply of exogenous propionate in VFA supply to the animal. Mechanisms other than hepatic oxidation of propionate might be responsible for DMI regulation.