Volatile Fatty Acid Concentrations Research Articles

Non-protein nitrogen supplementation on in vitro fermentation profile, methane production, and microbial nitrogen synthesis in a corn silage-based substrate.

Non-protein nitrogen (NPN) supplements improve animal performance in backgrounding diets. However, there is scarce information regarding the effect of different NPN sources and combinations on ruminal fermentation profile. The current study aimed to evaluate the effect of different NPN sources and their combinations on in vitro fermentation, microbial N synthesis, and methane (CH4) production in a backgrounding diet. Incubations were conducted on three separate days for 24h using corn silage and cotton gin byproduct (70% and 30% of DM, respectively) as substrate. Treatments were control (without NPN), urea, and five different proportions of urea-biuret and nitrate (100:0, 75:25, 50:50, 25:75, and 0:100). Each treatment, except control, was formulated to be isonitrogenous and equivalent to 1% urea inclusion. Ruminal fluid was collected from two ruminally cannulated Angus crossbred steers fed ad libitum corn silage and cotton gin byproduct plus 100g of a urea-biuret-nitrate mixture. The concentration of volatile fatty acids (VFAs) and ammonia nitrogen (NH3-N) were determined at 12 and 24h of incubation. Final pH, in vitro dry and organic matter digestibility, total gas production, and concentration of CH4 were determined at 24h. The supplementation of NPN increased (P < 0.05) the concentration of NH3-N at 12 and 24h. Although NPN supplementation increased (P < 0.05) the concentration of total VFA and acetate at 12h, treatments did not differ (P > 0.05) at 24h. Supplementation of NPN increased (P < 0.05) the proportion of acetate at 12 and 24h but tended to reduce (P = 0.054) the proportion of propionate only at 12h. Digestibility and pH were not different (P > 0.05) among treatments. Increasing nitrates in the NPN supplement increased (P < 0.05) the proportion of acetate and reduced (P < 0.05) the proportion of butyrate at 12 and 24h. The supplementation of NPN increased (P < 0.05) microbial N synthesis. Furthermore, increasing nitrate proportion in the NPN supplement increased (P < 0.05) the microbial N synthesis and efficiency of N use. Supplementation of NPN did not modify (P > 0.05) total gas or CH4 production. However, increasing nitrate proportion in the NPN supplement linearly reduced (P < 0.05) CH4 production. Supplementation of NPN increased NH3-N concentration and microbial N while increasing the inclusion of nitrate decreased the production of CH4 and increased the microbial N synthesis in a corn silage-based substrate under in vitro conditions.

OPTIMIZATION AND VALIDATION OF LIQUID-LIQUID EXTRACTION (LLE) METHOD AND THE APPLICATION OF GAS CHROMATOGRAPHY WITH FID DETECTOR FOR THE DETERMINATION AND QUANTIFICATION OF VOLATILE FATTY ACIDS IN EFFLUENTS FROM ANAEROBIC REACTORS

Controlling the chemical parameters of the anaerobic digestion (AD) process is essential for the bioconversion of organic matter to methane; among these parameters include the presence and concentration of volatile fatty acids (VFAs). It is thus necessary to use efficient analytical methods that are capable of identifying and quantifying VFAs in reactor effluents in order to obtain an immediate response to their conditions. In this study, the liquid-liquid extraction (LLE) method was optimized and validated − through an adaptation of the official method, using acetone and KHSO4, and gas chromatography with flame ionization detector (GC-FID) was used for the determination of acetic, propionic, isobutyric, butyric, isovaleric and valeric acids present in the effluents. The limit of detection (LOD) and limit of quantification (LOQ) obtained were 1.2-2.5 mg L-1 and 1.9-3.7 mg L-1, respectively, for all analytes. These low LODs and LOQs are essentially important because the presence of isobutyric and isovaleric acids above 5.0 mg can be considered indicative of imbalances in AD. The proposed method, which presented satisfactory results with good repeatability (4.2-20.7%) and recovery (90.9-104.0%) rates, was applied for the analysis of effluent samples from three continuous stirred-tank reactors (CSTR).

The influence of virginiamycin on digestion and ruminal parameters under feedlot conditions.

This experiment aimed to assess the impact of virginiamycin on in vitro gas production dynamics, rumen kinetics, and nutrient digestibility in beef steers fed a grain-based diet. Nine ruminally cannulated British-crossbred steers (596 ± 49kg) were assigned to this experiment. Animals were housed in three pens (n = 3/pen) equipped with a Calan gate feed system and water troughs. Pens were enrolled in a 3 × 3 Latin square design containing three periods of 16 d, and a 5-d washout interval between periods. Dietary treatments consisted of virginiamycin (VM) administration at 0 (VM0), 180 (VM180), or 240mg/d (VM240). During days 15 and 16 of each period, about 600mL of rumen fluid and urine samples were collected before (0h), and at 4, 8, 12, and 16h after the morning feed (0730 hours), rumen inoculum was used to take pH and redox potential measurements immediately after collection using a portable pH and redox meter, and subsamples were taken for volatile fatty acids (VFA) and NH3-N analyses, and urine samples were composited daily and analyzed for creatinine and purine derivatives (PD) content to estimate microbial crude protein flow. During the 4-h post-morning feed rumen collection, rumen inoculum was utilized to perform in vitro gas production measurements. Fecal samples were collected on day 16 of each period to estimate nutrient digestibility using acid detergent insoluble ash as an internal marker. Animals were considered the experimental unit for the statistical analyses, and periods and squares were included as random variables. The total and rate of gas production were similar among treatments (P ≥ 0.17). The second-pool (i.e., fiber) gas production increased linearly as VM inclusion increased (P = 0.01), with VM240 being greater compared to VM180 and VM0 (7.84, 6.94, and 6.89mL, respectively). Ruminal pH linearly increased as VM increased, with VM240 being greater than VM0 and VM180 intermediate (5.90, 5.82, and 5.86, respectively; P = 0.03). The VFA concentrations did not differ (P ≥ 0.13), but the acetate-to-propionate ratio was the highest in VM240 (P = 0.005). Branched-chain VFA increased (P ≤ 0.03) while lactate concentrations decreased (P = 0.005) linearly with VM. The ruminal NH3-N concentration was the lowest in the VM0 (P = 0.006). The estimated absorbed PD, purine derivative to creatinine index, and microbial N flow increased linearly with VM (P ≤ 0.07). The provision of VM influenced rumen dynamics in a dose-dependent manner.

Corticotropin-releasing hormone and vasopressin challenge affects metabolic, hematologic, and rumen fermentation parameters of growing beef steers.

The objective of this study was to evaluate the impacts of stress challenge duration on metabolic, hematologic, and rumen fermentation parameters of beef steers. Thirty steers (416 ± 19kg) were used in a randomized complete block design with 2 blocks and 3 treatments. Treatments were intravenous injection of (1) saline at 0, 24, 48, and 72h (n = 10; control); (2) corticotropin-releasing hormone (CRH) and vasopressin (VP) at 0h and saline at 24, 48, and 72h (n = 10; acute); or (3) CRH and VP at 0, 24, 48, and 72h (n = 10; chronic). Serum samples were collected at various time points for analysis of serum chemistry and nonesterified fatty acids (NEFA). Whole blood was collected for analysis of complete blood count, and ruminal fluid was collected via oral lavage to evaluate volatile fatty acid (VFA) composition. Serum cortisol was greater (treatment × hour; P ≤ 0.01) for cattle receiving acute and chronic than control at 1h (P < 0.01) and greater for chronic than acute and control at 25, 26, 49, 50, 73, and 74h (P < 0.01). Similarly, there was a treatment × hour interaction (P < 0.01) for serum glucose concentrations such that cattle receiving acute and chronic had greater glucose at 1h than control (P < 0.01), and cattle receiving chronic had greater glucose at 25, 49, 73, and 74h than acute and control (P ≤ 0.04). Serum insulin concentrations were greater (treatment × hour P < 0.01) in chronic and acute than control at 1h (P < 0.01) and greater for chronic compared to acute and control at 25, 49, and 73h (P ≤ 0.01). Serum NEFA tended (P = 0.09) to be greater in stressed cattle compared to control. There was a treatment × hour interaction (P = 0.003) for total white blood cell count such that chronic had greater concentration than control at 72h (P < 0.01). Conversely, monocyte concentration was less (treatment × hour interaction P < 0.01) for chronic than acute and control at 144h (P < 0.01) and eosinophil concentration was greater (treatment × hour interaction P = 0.02) for chronic than control steers at 48h (P = 0.02) and greater for chronic than acute at 72 and 144h (P ≤ 0.03). Minimal differences were observed in VFA concentrations with the exception of acetate (treatment × hour interaction P = 0.05). These results demonstrate that administration of CRH and VP affects complete blood count and serum chemistry, and longer duration of treatment exposure prolongs the physiological responses to a stress challenge.

Effects of pellet starch levels in automatic milking systems on rumen fermentation, plasma metabolites, and milk production in mid-lactation cows.

The aim of this study was to evaluate whether the starch levels in pellets fed to cows in automatic milking systems (AMS) affect subacute ruminal acidosis (SARA) occurrence and metabolite parameters. Twenty-four lactating cows (124.4 ± 49.9 days in milk) were studied in a crossover design with two periods of 21 days each and two treatment groups-a control group fed AMS pellets containing 30.0% of starch dry matter (DM) and an experimental group fed AMS pellets containing 23.5% of starch DM. All cows received the same partial mixed ration (PMR). The 1-hr mean ruminal pH in both groups decreased over 4 hr after feeding on PMR but recovered by the next morning. The ruminal pH was unaffected by either treatment, and both groups developed SARA. The groups had no significant differences in the concentrations of ruminal volatile fatty acids, lipopolysaccharides, plasma acute-phase proteins, other metabolites, and hormones. The milk yield and composition were not different in both groups. Feeding low-starch pellets in the AMS did not contribute to the risk of SARA occurrence in cows and had no additive effects on rumen fermentation, plasma metabolites, or milk production.

Investigating the effect of supplementing different levels of Isochrysis galbana on in vitro rumen fermentation parameters.

This study aimed to investigate the effect of supplementing Isochrysis galbana (I. galbana) at levels of 0 (control), 1, 2, 3, 4, and 5 (g/100 g DM) of the diet on the gas production kinetics, methane production, rumen fermentation parameters, and relative microbial population in vitro. Supplementation of I. galbana at high level (5g/100 g DM) caused a significant decrease in total gas production (p < 0.05). High supplementation rates (4 and 5g/100 g DM) decreased CH4 production relative to the control by 18.4% and 23.2%, respectively. Although rumen ammonia nitrogen (N-NH3) and total volatile fatty acids (VFA) concentrations were affected by dietary treatments, but the VFA profile did not changed. The relative proportion of protozoa and methanogenic archaea as well as Anaerovibrio lipolytica, Prevotella spp., Ruminococcus flavefaciens, and Fibrobacter succinogenes were decreased significantly as a result of microalgae supplementation. However, the relative abundance of Ruminococcus albus, Butyrivibrio fibrisolvens and Selenomonas ruminantium were significantly increased (p < 0.05), related to the control group. As well, the pH was not affected by dietary treatments. It was concluded that I. galbana reduced in vitro CH4 production and methanogenic archaea that its worth to be investigated further in in vivo studies.

Feeding limestone buffer to limit-fed dairy steers fed a high inclusion rate of distiller grains.

The study objective was to evaluate dietary limestone buffer inclusion rates for impacting nutrient digestibility and excretion when growing dairy cattle are fed high distiller grains with solubles (DDGS) limit-fed ration. The hypothesis was that feeding more limestone buffer would offset a low rumen pH when feeding a high DDGS inclusion rate. Five ruminally cannulated Holstein and Brown Swiss steers were used in a crossover design having 2-wk periods to evaluate high and low buffer inclusion rates when limit-fed. Treatments were similar in ingredient composition being: 1) 40% DDGS at 0.80% high CaCO3 buffer inclusion (HIGH) and 2) 40% DDGS with 0.25% low CaCO3 buffer inclusion (LOW) with the remaining ration consisting of grass hay with minerals and vitamins. Rations were limit-fed at 2.50% of body weight (BW) using Calan feeding doors with steers being weighed every 2wk with ration amounts adjusted accordingly. Rumen fluid was collected via the ruminal cannula at the start and end of each period for pH, ammonia-n, and volatile fatty acid (VFA)s. Fecal grab samples were collected at the end of each period for measurement of total-tract nutrient digestibility. There were no treatment-by-period interactions (P > 0.10) for any of the growth parameters measured. Gains in frame growth parameters were similar (P > 0.10) for steers fed both rations. BWs and gains were similar (P > 0.10) for steers fed both rations. Steers fed the LOW ration demonstrated a numeric improvement in average daily gain combined with a tendency (P < 0.06) for lower dry matter intake resulting in an improved (P < 0.01) feed efficiency (gain:feed) compared with steers fed the HIGH ration. Steers fed HIGH demonstrated greater (P < 0.01) ruminal ammonia-N and isovalerate concentrations compared with steers fed the LOW buffer ration. Steers fed both buffer inclusion rates were similar (P > 0.10) for ruminal pH and remaining VFAs concentrations. Steers fed both buffer inclusion rates were similar (P > 0.10) in DM and organic matter digestibilities. Limit-feeding a high DDGS inclusion rate ratio combined with a low buffer inclusion rate improved feed efficiency while maintaining growth performance. The study hypothesis was rejected in that feed efficiency can be enhanced when feeding a high DDGS ration by feeding a low calcium carbonate buffer.

Effect of wheat middling incorporation into wet corn distillers grains with solubles on apparent diet digestibility and ruminal fermentation characteristics in growing and finishing diets.

Two separate cross-over experiments were conducted to evaluate the effects of incorporating wheat middlings into wet corn distillers grains with solubles (WDGS) on apparent diet digestibility and ruminal fermentation characteristics in growing and finishing diets. In experiment 1, four ruminally cannulated heifers (313 ± 42.9kg) were limit fed a high-energy growing diet that included WDGS (CON) or WDGS + wheat middlings (CON + WM) at 40% of diet dry matter (DM). The diet also contained (DM basis) 39.5% dry-rolled corn, 7.5% supplement, and 13% warm-season grass hay. In experiment 2, four ruminally cannulated Holstein steers (321 ± 17.4kg) were fed a finishing diet that included WDGS (CON) or WDGS + wheat middlings (CON + WM) at 30% of diet DM. The diet also contained (DM basis) 60.3% dry-rolled corn, 2.7% supplement, and 7.0% warm-season grass hay. Experiments consisted of two 15-d periods that were conducted concurrently. Each period included 10 d of diet adaptation, 4 d of fecal collection, and 1 d of ruminal fluid collection. Fecal samples were collected on days 11 to 14 of each period and composite samples were analyzed for chromium to estimate apparent diet digestibility. On day 15, ruminal fluid samples were collected prior to feeding and again at 2, 4, 6, 8, 12, 18, and 24-h post-feeding. In experiment 1, DM, organic matter (OM), neutral detergent fiber (NDF), and acid detergent fiber (ADF) intake did not differ (P ≥ 0.11) between diets; however, starch intake was greater (P = 0.03) for heifers fed CON + WM compared with CON. Apparent DM, OM, NDF, and starch digestibilities were similar between diets (P ≥ 0.13), but feeding CON + WM tended to lead to lesser (P = 0.06) apparent ADF digestibility. Ruminal pH and total volatile fatty acid concentrations did not differ between diets (P ≥ 0.16); however, ruminal ammonia concentrations tended to be less (P = 0.09) for CON + WM compared with CON. In experiment 2, DM intake did not differ (P = 0.65) between diets. Apparent DM digestibility was greater (P = 0.01) for CON + WM compared with CON but the difference was small. Intake and apparent digestibility of OM, NDF, ADF, and starch did not differ (P ≥ 0.25) between diets. Ruminal ammonia concentrations were lesser (P = 0.03) while ruminal pH was greater (P = 0.02) for CON + WM compared with CON. Overall, incorporation of wheat middlings into WDGS had minimal impacts on feed intake, apparent diet digestibility, and ruminal fermentation characteristics when fed to growing and finishing cattle.

Almond hulls and shells as an alternative fiber source in limit-fed growing beef cattle diets.

Almond hulls and shells are a by-product of almond production that can be incorporated as a feed ingredient in beef cattle diets. Three experiments were conducted to determine the effects of hammermill screen size on almond hull and shell bulk density and inclusion of ground or non-ground almond hulls and shells in limit-fed growing diets on growth performance, diet digestibility, and ruminal fermentation characteristics of beef cattle. In experiment 1, almond hulls and shells were ground with a laboratory-scale hammermill using no screen, a 11.1-mm screen, a 19.1-mm screen, or a 25.4-mm screen. Each screen-size treatment was ground at three separate time points (n= 3 replications/treatment). Grinding almond hulls and shells with no screen increased bulk density by 111% and minimized proportions of fine particles; therefore, almond hulls and shells ground using no screen were included as a treatment in the following experiments. In experiment 2, 364 steers (initial body weight [BW]: 257± 20.7kg) were blocked by truckload (n = 4), stratified by BW, and assigned to pen within block. Pens were randomly assigned to 1 of 4 experimental diets (n= 10 pens/treatment). The control diet (CON) contained (DM basis) 39.5% dry-rolled corn, 7.5% supplement, 40% wet-corn gluten feed, and 13% prairie hay. Non-ground (13AH) or ground (13GAH) almond hulls and shells replaced prairie hay and were fed at 13% of diet DM or non-ground almond hulls and shells were fed at 26% of diet DM and replaced 13% prairie hay and 13% dry-rolled corn (26AH). Diets were limit-fed at 2.2% of BW daily (DM basis) for 56 d. Overall average daily gains (ADG) were greater (P ≤ 0.05) for CON, 13AH, and 13GAH compared with 26AH. In addition, ADG from days 14 to 56 were greater (P= 0.03) for 13GAH and tended to be greater (P = 0.09) for 13AH compared with CON. Experiment 3 was a 4 × 4 replicated Latin square in which 8 ruminally cannulated heifers (initial BW = 378 ± 44.0kg) were fed diets from experiment 2. Apparent dry matter digestibility did not differ (P = 0.21) among treatments. Total ruminal volatile fatty acid concentrations were greater (P ≤ 0.03) for 13GAH and 13AH compared with 26AH and tended (P = 0.06) to be greater for 13GAH compared with CON. Overall, almond hulls and shells can be utilized as an alternative to prairie hay in limit-fed growing diets without negatively influencing rates of gain or diet digestibility.

In vitro fermentation characteristic and digestibility of dairy ration supplemented with Aspergillus oryzae inoculum

In vitro experiment has been carried out to study the effect of Aspergillus oryzae inoculum (AOI) supplementation on dairy cow rations. The observed effects include the digestibility of crude protein, NDF, dry matter and organic matter in the in vitro digestive system of the ration using rumen-buffer fluid mixture. The Experiment design using complete randomize design (CRD) consist of four treatments: Control (Commercial dairy feed), C2 (Commercial dairy feed + 2 g AOI), C4 (Commercial dairy feed + 4 g AOI) and C8 (Commercial dairy feed + 8 g AOI). The additional administration of 2, 4 and 8 grams of AOI/kg rations showed a significant difference (p<0.05) of the total volatile fatty acid content. However, the ratio of acetate/propionate (A/P) was reduced significantly. The highest increase in protein, fiber and dry matter digestibility was shown by C4 treatment (supplementation of 4 g AOI/kg ration). Based on the results of this in vitro study, the supplementation of AOI to dairy cow rations improves the digestibility of nutrients in feed.

Investigations of morphological development, digestive enzymes and microbiome of the gastrointestinal tract in goat kids from birth to adulthood

ABSTRACT The development of gastrointestinal tracts in goats after birth is critical for establishment of digestion and absorption function, growth, immunity and health of adults. However, this process from birthday to adulthood is lacking. This study was conducted to determine the anatomical, morphological, physiological and microbiome development of the gastrointestinal tract of Leizhou goats. The weights of rumen, reticulum, omasum and abomasum increased with age. The weights of each intestinal segment increased with age. The length and width of rumen papilla, muscular thickness, cuticle thickness and wall thickness were significantly increased with developmental stage. Consistently, the villus length and width and crypt depth of the small intestine increased significantly with age. The volatile fatty acids (VFAs) concentration in both rumen and caecum increased with ages. Specifically, VFAs were not detected at birthday rumen, while they showed in caecum. The activities of digestive enzymes in both rumen and caecum had a similar pattern with VFAs. The microbial diversity and composition were distinct between the rumen and caecum after birth. We observed a rapid influx of microbes in rumen and caecum at birthday and gradually changed from 1 month of age to adulthood. This study provides insights into feeding and health maintenance strategies.

Enzyme production mechanism of anaerobic fungus Orpinomyces sp. YF3 in yak rumen induced by different carbon source

In order to investigate the enzyme production mechanism of yak rumen-derived anaerobic fungus Orpinomyces sp. YF3 under the induction of different carbon sources, anaerobic culture tubes were used for in vitro fermentation. 8 g/L of glucose (Glu), filter paper (Flp) and avicel (Avi) were respectively added to 10 mL of basic culture medium as the sole carbon source. The activity of fiber-degrading enzyme and the concentration of volatile fatty acid in the fermentation liquid were detected, and the enzyme producing mechanism of Orpinomyces sp. YF3 was explored by transcriptomics. It was found that, in glucose-induced fermentation solution, the activities of carboxymethyl cellulase, microcrystalline cellulase, filter paper enzyme, xylanase and the proportion of acetate were significantly increased (P < 0.05), the proportion of propionate, butyrate, isobutyrate were significantly decreased (P < 0.05). The results of transcriptome analysis showed that there were 5 949 differentially expressed genes (DEGs) between the Glu group and the Flp group, 10 970 DEGs between the Glu group and the Avi group, and 6 057 DEGs between the Flp group and the Avi group. It was found that the DEGs associated with fiber degrading enzymes were significantly up-regulated in the Glu group. Gene ontology (GO) function enrichment analysis identified that DEGs were mainly associated with the xylan catabolic process, hemicellulose metabolic process, β-glucan metabolic process, cellulase activity, endo-1,4-β-xylanase activity, cell wall polysaccharide metabolic process, carbohydrate catabolic process, glucan catabolic process and carbohydrate metabolic process. Moreover, the differentially expressed pathways associated with fiber degrading enzymes enriched by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were mainly starch and sucrose metabolic pathways and other glycan degradation pathways. In conclusion, Orpinomyces sp. YF3 with glucose as carbon source substrate significantly increased the activity of cellulose degrading enzyme and the proportion of acetate, decreased the proportion of propionate, butyrate and isobutyrate. Furthermore, the degradation ability and energy utilization efficiency of fungus in the presence of glucose were improved by means of regulating the expression of cellulose degrading enzyme gene and participating in starch and sucrose metabolism pathway, and other glycan degradation pathways, which provides a theoretical basis for the application of Orpinomyces sp. YF3 in practical production and facilitates the application of Orpinomyces sp. YF3 in the future.

Effect of crossbreeding and dietary neutral detergent fiber (NDF) levels on feed intake, nutrient digestibility, rumen parameters and nitrogen retention of beef cattle

This experiment sought to evaluate the influence of varying levels of neutral detergent fiber (NDF) in the diet on feed intake, nutrient digestibility, rumen conditions, and nitrogen retention in crossbred cattle. Beef cattle aged 18 months were organized into groups using a 2x (4x4) Latin square design. The NDF levels investigated were 47%, 51%, 55%, and 59% of dry matter (referred to as NDF47, NDF51, NDF55, and NDF59 treatments, respectively). While dry matter (DM) consumption per 100 kg body weight (BW) did not exhibit significant differences between treatments, Charolais crossbred cattle (2.16 kg DM) demonstrated higher intake than Black Angus crossbred cattle (2.04 kg DM). Metabolizable energy intake in Charolais crossbred cattle significantly differed from that in Black Angus crossbred cattle (17.6 and 16.7 MJ/100 kg BW, respectively). Regarding NDF treatments, NDF47 did not differ from NDF51 and NDF55, but it was significantly higher (P&lt;0.05) than the NDF59 treatment (18.1, 17.3, 17.1, and 16.0 MJ/100 kg BW, respectively). Although dry matter and organic matter digestibility did not significantly differ between Charolais and Black Angus crossbred cattle, variations were noted among treatments (P&lt;0.05). Specifically, DM digestibility of NDF47 (62.8%) was significantly higher than NDF59 (55.4%), with no significant differences observed for NDF51 (59.8%) and NDF55 treatments (58.9%). Rumen pH, N-NH3, and total volatile fatty acid concentrations at 0h and 3h post-feeding did not exhibit significant differences (P&gt;0.05) in this study. However, nitrogen retention in Black Angus crossbred cattle was significantly lower than in Charolais crossbred cattle (0.124 and 0.166 g/kg BW, respectively). Across treatments, nitrogen retention values were numerically higher (P&gt;0.05) in NDF47, NDF51, NDF55, and NDF59 treatments (0.166, 0.148, 0.139, and 0.126 g/kg BW, respectively). In summary, this study determined that Charolais crossbred cattle displayed increased feed intake, crude protein digestibility, and nitrogen retention compared to Black Angus crossbred cattle. Furthermore, a dietary NDF level of 55% was suggested as suitable for practical use in terms of feed utilization by farmers. Keywords: Forage, crossbreeding, rumen fermentation, and ruminant. Abbreviations: DM: dry matter, OM: organic matter, CP: crude protein, NDF: neutral detergent fiber and ME: metabolic energy, BW: body weight. NDF

Response of rumen microorganisms to pH during anaerobic hydrolysis and acidogenesis of lignocellulose biomass

Rumen microorganisms can efficiently degrade lignocellulosic wastes to produce volatile fatty acids (VFAs). pH is a key factor in controlling the type and yield of VFAs by affecting the microorganisms involved in rumen fermentation. However, the effects of different pH on rumen microbial diversity, communities, and mechanisms are unclear. In this study, the hydrolysis and acidogenesis of corn straw and diversity, communities, and mechanisms of rumen microorganisms were explored at different initial pHs. Results showed that the highest hemicellulose, cellulose, and lignin degradation efficiency of corn straw was 55.2 %, 38.3 %, and 7.01 %, respectively, and VFA concentration was 10.2 g/L at pH 7.0. Low pH decreased the bacterial diversity and increased the fungal diversity. Rumen bacteria and fungi had different responses to initial pHs, and the community structure of bacteria and fungi had obviously differences at the genus level. The core genera Succiniclasticum, Treponema, and Neocallimastix relative abundance at initial pH 7.0 samples were significantly higher than that at lower initial pHs, reaching 6.01 %, 1.61 %, and 5.35 %, respectively. The bacterial network was more complex than that of fungi. pH, acetic acid, and propionic acid were the main factors influencing the bacterial and fungal community structure. Low pH inhibited the expression of functional genes related to hydrolysis and acidogenesis, explaining the lower hydrolysis and acidogenesis efficiency. These findings will provide a better understanding for rumen fermentation to produce VFAs.

Effect of extracellular polymeric substances removal and re-addition on anaerobic digestion of waste activated sludge

Extracellular polymeric substances (EPS) play a key role in anaerobic digestion of excess sludge. The influence of EPS removal and re-addition on sludge anaerobic digestion were investigated by batch experiment. The results showed that both EPS removal and re-addition improved sludge anaerobic digestion, the cumulative methane production increased by 14.9 % and 50.4 %. EPS removal promoted sludge hydrolysis and acidification, the soluble chemical oxygen demand (SCOD) and volatile fatty acids (VFAs) concentration increased by 31 % and 29 %. The re-addition of EPS increased the substrate of sludge fermentation, resulting in 1.64 and 1.77 times higher SCOD and VFAs concentration than that of control group. In addition, EPS contained lots of electrochemically active substances, and re-adding EPS increased the electron transfer system activity in anaerobic digestion by 164 %, which enhanced significantly methane production. Both removal and re-addition of EPS altered the microbial community structure in anaerobic digestion, the bacteria with hydrolysis and acidification functions were enriched, such as Chloroflexi and Desulfobacterota. Methanobacterium and Methanosaeta were the dominant methanogens in anaerobic digestion systems, and their relative abundance were increased by removing and re-adding EPS.

Influence of adding sage leaves on growth performance, nutrient digestibility, and rumen fermentation in Awassi lambs

This study was conducted to determine the effect of adding different levels of sage leaf powder (SLP) to the diet of local Awassi lambs on growth performance, feed intake, digestibility and rumen fermentation. Sixteen Awassi male lambs 4-5 months of age were randomly distributed into four treatment groups: no feed additive (SLP0), 5g (SLP5), 10g (SLP10) and 15 g (SLP15) of sage leaves powder/kg of dry matter (DM) were added to the diet. Results revealed that adding SLP did not affect feed intake. However, growth performance, dry matter and organic matter digestion were recorded higher significances (P≤0.05) in lambs fed SLP5 and SLP10 than in lambs fed SLP15 and SLP0. Total volatile fatty acids concentrations were significantly increased (P≤0.05) in lambs fed SLP5 than other lambs. In conclusion, the addition of SLP at 5g/kg DM in the diet of Awassi lambs improved growth performance and nutrient digestibility with a positive effect on ruminal fermentation. Keywords: Salvia officinalis; Awassi lambs; Growth performance; Nutrient digestibility; Rumen fermentation

Rumen fermentation of meal-fed sheep in response to diets formulated to vary in fiber and protein degradability.

The concentration of volatile fatty acid (VFA) provides an imprecise view of VFA dynamics due to the confounding effects of fluid pool size and dynamics. Determination of VFA flux using isotope is expensive and a complex methodology. Therefore, a rapid and affordable approach to explore VFA dynamics may allow comprehensive characterization of VFA availability. The objective of this study was to explore the use of VFA dynamics generated by meal feeding to derive time-series rates of VFA apparent appearance and disappearance driven by different protein and fiber sources. Six ruminally cannulated wethers were fed diets containing timothy hay or beet pulp (TH and BP) and soybean meal (SBM) or heated soybean meal (HSBM). Diets were, TH + HSBM; TH + SBM; BP + HSBM; and BP + SBM and the experimental design was a partially replicated 4 × 4 Latin Square. Concentrations of VFA and polyethylene glycol (PEG) in rumen fluid samples were estimated. Concentrations of PEG were used to estimate fluid passage and volume to calculate VFA mass, and fluid-mediated exit. Maximum apparent appearance rate (mmol/h), the rate of apparent appearance decline (mmol/mmol/h), mean apparent appearance flux (mmol/h), mean apparent disappearance (mmol/h), and apparent disappearance rate (mmol/mmol/h) were estimated by deriving a 1 pool model for each VFA on a mass basis where appearance was assumed to follow an exponential decay pattern and disappearance followed mass-action kinetics. Statistical analyses were conducted using a linear mixed effect regression with fixed effects for fiber source, protein source, and their interaction, as well as random effects for animal and period. Rumen fluid volume (L) was greater in HSBM diets (P = 0.033) and fluid passage (%/h) was greater in SBM diets (P = 0.048). Concentrations (higher acetate and butyrate, P = 0.002 and 0.004, respectively) and molar proportions (higher valerate, P = 0.035) of VFA were affected only by fiber source; however, protein source and fiber source interacted to significantly influence apparent appearance rates and absorption rates of many major VFA. On a flux basis, HSBM supported significantly elevated mean disappearance of propionate (P = 0.033). This data demonstrates that time-series evaluation of fermentation dynamics, including fluid dynamics and VFA concentrations can be used to estimate apparent appearance and disappearance of VFA. Although further work is needed to confirm the alignment of these estimates with measurements of VFA supplies to the animal, this modeling approach may provide a simpler way to better understand the kinetics of rumen.

Microencapsulated Sodium Butyrate Alleviates Immune Injury and Intestinal Problems Caused by Clostridium Perfringens through Gut Microbiota.

Microencapsulated sodium butyrate (MS-SB) is an effective sodium butyrate additive which can reduce the release of sodium butyrate (SB) in the fore gastrointestinal tract. In this study, we assess the protective effects and mechanisms of MS-SB in Clostridium perfringens (C. perfringens)-challenged broilers. Broiler chickens were pre-treated with SB or MS-SB for 56 days and then challenged with C. perfringens three times. Our results indicate that the addition of MS-SB or SB before C. perfringens infection significantly decreased the thymus index (p < 0.05). Serum IgA, IgY, and IgM concentrations were significantly increased (p < 0.05), while pro-inflammatory IL-1β, IL-6, and TNF-α were significantly decreased (p < 0.05) under MS-SB or SB supplementation. Compared with SB, MS-SB presented a stronger performance, with higher IgA content, as well as a lower IL-1β level when normal or C. perfringens-challenged. While C. perfringens challenge significantly decreased the villus height (p < 0.05), MS-SB or SB administration significantly increased the villus height and villus height/crypt depth (V/C ratio) (p < 0.05). Varying degrees of SB or MS-SB increased the concentrations of volatile fatty acids (VFAs) during C. perfringens challenge, where MS-SB presented a stronger performance, as evidenced by the higher content of isovaleric acid and valeric acid. Microbial analysis demonstrated that both SB or MS-SB addition and C. perfringens infection increase variation in the microbiota community. The results also indicate that the proportions of Bacteroides, Faecalibacterium, Clostridia, Ruminococcaceae, Alistipes, and Clostridia were significantly higher in the MS-SB addition group while, at same time, C. perfringens infection increased the abundance of Bacteroides and Alistipes. In summary, dietary supplementation with SB or MS-SB improves the immune status and morphology of intestinal villi, increases the production of VFAs, and modulates cecal microbiota in chickens challenged with C. perfringens. Moreover, MS-SB was more effective than SB with the same supplemental amount.

Kinetic Model of Anaerobic Digestion from Chicken Manure and Thai Rice Noodle Wastewater in Continuous Reactors

&lt;p&gt;A kinetic model was used to describe the anaerobic co-digestion of chicken manure (CM) and Thai rice noodle wastewater (TRNW) in continuous reactors. This research investigated the effects of mixing interval and hydraulic retention time (HRT) on methane production and other related kinetic parameters. Experiments were carried out in three identical reactors with different mixing conditions: 1) without mixing, 2) mixing every 6 hours, and 3) mixing every 12 hours. Each reactor was operated at HRT of 10, 20, and 30 days, respectively. The anaerobic co-digestion was conducted at room temperature (28-30 ºC). The results showed that the co-digestion provided suitable initial conditions for anaerobic microorganisms in terms of pH level (7.1 ± 0.04), alkalinity (3,420 ± 20.00 mg/LasCaCO3), and volatile fatty acid (VFA) concentration (480 ± 10.00 mg/LasCH3COOH). The co-digestion of the mixing interval of every 12 hours and HRT of 10 days provided the highest methane production potential with an average of 261 mLCH4/gCOD. The model was validated statistically and can provide beneficial information for designing co-anaerobic wastewater treatment plants in the mixing interval and HRT suitable for biogas production.&lt;/p&gt;&#x0D;

Effects of microbial deodorizer on pig feces fermentation and the underlying deodorizing mechanism

Microbial deodorization is a novel strategy for reducing odor in livestock and poultry feces. Herein, 12 strains of ammonia (NH3) and 15 hydrogen sulfide (H2S) removing bacteria were obtained with a removal efficiency of 65.20–79.80% and 34.90–79.70%, respectively. A novel bacteria deodorant named MIX (Bacillus zhangzhouensis, Bacillus altitudinis, and Acinetobacter pittii at a ratio of 1:1:2) were obtained. MIX can shorten the temperature rising stage by 2 days and prolong the thermophilic stage by 4 days. The ability of MIX to remove NH3, H2S, and volatile fatty acids (VFAs) and the underlying removal mechanism were analyzed during pig feces fermentation. MIX can significantly reduce the concentrations of NH3 and H2S by 41.82% and 66.35% and increase the concentrations of NO3−–N and SO42− by 7.80% and 8.83% (P < 0.05), respectively, on the 25th day. Moreover, the concentrations of acetic, propionate, iso-valerate, and valerate were significantly reduced. The dominant bacteria communities at the phylum level were Firmicutes, Proteobacteria, Bacteroidetes, and Spirochaetes. B. zhangzhouensis and B. altitudinis could convert NH4+–N to NO3−–N, and A. pittii could transfer H2S to SO42−. This study revealed that bacteria deodorant can reduce the concentrations of NH3, H2S, and VFAs in pig feces and increase those of NH4+, NO3−, and SO42− and has excellent potential in deodorizing livestock and poultry feces composting.