Fermentation Characteristics Research Articles

Temperature-Dependent Metabolic Interactions Between Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus in Milk Fermentation: Insights from GC-IMS Metabolomics

Streptococcus (S.) thermophilus and Lactobacillus (L.) delbrueckii ssp. bulgaricus are widely used as a combined starter culture for milk fermentation, often at temperatures of 37°C and 42°C. To investigate the metabolic interplay between these 2 species during the fermentation process, this study examined the growth and fermentation characteristics of different S. thermophilus strains cocultured with L. delbrueckii ssp. bulgaricus ND02 at these 2 temperature conditions. Gas chromatography-ion mobility spectrometry (GC-IMS) metabolomics was employed to analyze changes in the milk metabolome during 3 key fermentation stages: initiation (F0, pH 6.50 ± 0.02), curdling (F1, pH 5.20 ± 0.02), and endpoint (F2, pH 4.50 ± 0.02). The results showed that 42°C fermentation promoted rapid bacterial growth, with significantly reduced fermentation time compared with 37°C. Interestingly, 37°C fermentation favored the enrichment of volatile fatty acids like 2-methylpropanoic acid, 3-methylbutanoic acid, and ethyl acetate. In contrast, 42°C fermentation led to increased levels of ketones such as acetone, 2-hexanone, 2-pentanone, and 2-heptanone. Sensory evaluation indicated that the 42°C fermented milk had higher overall scores. Discriminatory flavor metabolites were more abundant during the later fermentation stage (F1 to F2), while the underlying metabolic pathways became increasingly active. These findings provide insights into the dynamic changes in volatile metabolite profiles of fermented milk produced under different temperature and time conditions using varied starter culture combinations. The results are valuable for optimizing dairy fermentation processes and product quality.

Structural characterization, antioxidant activity, and fermentation characteristics of Flammulina velutipes residue polysaccharide degraded by ultrasonic assisted H2O2-Vc technique

Adhere to the concept of low-carbon environmental protection and turning waste into treasure, polysaccharides from Flammulina velutipes residue polysaccharide (FVRP) has been developed and possesses diverse bioactivities, comprising antioxidant, hypoglycemic, and relieving heavy metal damage, which still has the disadvantages of high molecular weight and low bioavailability. The current work is the first to prepare a degraded polysaccharide (FVRPV) from FVRP by ultrasonic assisted H2O2-Vc technique in order to reduce its molecular weight, thereby improving its activity and bioavailability. Our results found that the molecular weight and average particle size were declined, but the monosaccharide composition and characteristic functional group types of FVRPV had no impact. The structural changes of polysaccharides analyzed by XRD, Congo Red test, I2-KI, SEM, and methylation analysis indicated that the surface morphology and glycosidic bond composition of FVRPV possessed longer side chains and a greater number of branches with an amorphous crystal structure devoid of a triple helix configuration, and had experienced notable alterations after ultrasonic assisted H2O2-Vc treatment. Meanwhile, the in vitro antioxidant capacity of FVRPV had significantly increased compared to FVRP, implying ultrasonic assisted H2O2-Vc technique maybe a effective method to enhance the bioactivity of polysaccharides. In addition, the content of polysaccharide, reducing sugar, and uronic acid in FVRPV was significantly decreased, but antioxidant capacity of fermentation broth was stronger by in vitro human fecal fermentation. The 16S rDNA sequencing data displayed that FVRPV can enrich probiotics and reduce the abundance of pathogenic bacteria through different metabolic pathways mediated by gut microbiota, thereby exerting its potential probiotic effects. The interesting work provides a novel degraded polysaccharide by ultrasonic assisted H2O2-Vc technique, laying a foundation for developing FVRPV as a new antioxidant and prebiotic.

The anti-methanogenic efficacy of Asparagopsis armata: Could it be attributable solely to its bromoform content?

The seaweed Aspragopsis armata has been shown to be a successful intervention to mitigate methane (CH4) emissions from ruminants due to the content of halogenated components, including bromoform. Some groups have been exploring extracting or synthesizing bromoform to be used as a feed additive rather than using whole seaweed biomass. This study was conducted to understand the differences between whole A. armata biomass and bromoform in their ability to reduce CH4 production when included in ruminant diets. A series of in vitro experiments were conducted, with a control group consisting of a 50 % hay:50 % concentrate. A. armata biomass supplementation levels of 0.25 and 0.50 %, containing 0.0037 and 0.0077 mg bromoform on a dry matter (DM) basis, respectively, were evaluated. Bromoform was evaluated at 0.0018, 0.0036, and 0.0073 mg. The two highest levels of bromoform were comparable to the bromoform content in the seaweed biomass. Adding A. armata biomass led to significant reductions in CH4 yield (mL/g) of 62.5 and 95.6 %, respectively, without compromising in vitro fermentation characteristics. The addition of bromoform resulted in a decrease in the CH4 yield (mL/g) by 7.6, 23.0, and 59.6 %, respectively. In conclusion, while bromoform led to a dose-dependent reduction in CH4 production, A. armata has a greater effect at equivalent doses of bromoform, suggesting that the other components in the biomass, which were responsible for up to 40 % of the reduction, play a significant role in the anti-methanogenic efficiency of A. armata.

Effects of four kinds of improver on fermentation characteristics of gluten-free rice dough.

Rice is commonly utilized as a wheat bread substitute due to its low allergenicity. However, rice bread faces challenges in processing efficiency and the formation of a cohesive gel network structure, resulting in suboptimal taste Hence, this study compared four improvers-trypsin, whey protein (WPC), hydroxypropyl methyl cellulose (HPMC), and molecularly distilled monoglycerides (GMSs). The impacts of the four improvers on the processing attributes of rice dough were comprehensively assessed across fermentation, moisture content analysis, rheology, heat stability, and pasting characteristics. The findings indicated that the incorporation of trypsin, HPMC, and WPC resulted in 107%, 61%, and 1% increases in gas production of fermented rice dough, respectively, while reducing the regrowth values to 564.00±7.21, 176.67±0.58, and 611.00±3.61cP. Notably, the air-holding capacity of HPMC-fermented rice dough exhibited a 7% enhancement. All four types of improvers raised the enthalpy of melting (ΔH) and the difference in melting point (ΔT) of fermented rice doughs, with trypsin enhancing ΔH by 44% and ΔT by 40%. GMS, HPMC, and WPC increased the degree of water incorporation in fermented doughs. This study could serve as a benchmark for enhancing the fermentation attributes of rice dough and establish a groundwork for the future advancement of gluten-free dietary options. PRACTICAL APPLICATION: The thorough analysis conducted in this experiment provides a theoretical framework for rice dough preparation during the fermentation process, addressing the dietary needs of individuals with coeliac disease and those following a gluten-free diet. This study also paves the way for the development of improved gluten-free rice products in future research pursuits.

Effect of konjac glucomannan on gut microbiota from hyperuricemia subjects in vitro: fermentation characteristics and inhibitory xanthine oxidase activity.

The disorder of uric acid metabolism is closely associated with gut microbiota and short-chain fatty acids (SCFAs) dysregulation, but the biological mechanism is unclear, limiting the development of uric acid-lowering active polysaccharides. Konjac glucomannan (KGM) could attenuate metabolic disturbance of uric acid and modulate the gut microbiota. However, the relationship between uric acid metabolism and gut microbiota is still unknown. In this study, The fecal samples were provided by healthy volunteers and hyperuricemia (HUA) patients. Fecal samples from healthy volunteers was regarded as the NOR group. Similarly, 10% HUA fecal suspension was named as the HUA group. Then, fecal supernatant was inoculated into a growth basal medium containing glucose or KGM, and healthy fecal samples were designated as the NOR-GLU and NOR-KGM groups, while HUA fecal samples were designated as the HUA-GLU and HUA-KGM groups. All samples were cultured in an anaerobic bag system. After fermentation for 24 h, the samples were collected for further analysis of composition of intestinal microbiota, SCFAs concentration and XOD enzyme activity. The results showed that KGM could be utilized and degraded by the gut microbiota from HUA subjects, and it could modulate the composition and structure of their HUA gut microbiota to more closely resemble that of a healthy group. In addition, KGM showed a superior modulated effect on HUA gut microbiota by increasing Megasphaera, Faecalibacterium, Lachnoclostridium, Lachnospiraceae, Anaerostipes, and Ruminococcus levels and decreasing Butyricicoccus, Eisenbergiella, and Enterococcus levels. Furthermore, the fermentation solution of KGM showed an inhibitory effect on xanthine oxidase (XOD) enzyme activity, which might be due to metabolites such as SCFAs. In conclusion, the effect of KGM on hyperuricemia subjects was investigated based on the gut microbiota in vitro. In the present study. It was found that KGM could be metabolized into SCFAs by HUA gut microbiota. Furthermore, KGM could modulate the structure of HUA gut microbiota. At the genus level, KGM could decrease the relative abundances of Butyricicoccus, Eisenbergiella, and Enterococcus, while Lachnoclostridium and Lachnospiraceae in HUA gut microbiota were significantly increased by the addition of KGM. The metabolites of gut microbiota, such as SCFAs, might be responsible for the inhibition of XOD activity. Thus, KGM exhibited a superior probiotic function on the HUA gut microbiota, which is expected as a promising candidate for remodeling the HUA gut microbiota.

Various steaming durations alter digestion, absorption, and fermentation by human gut microbiota outcomes of Polygonatum cyrtonema Hua polysaccharides.

Different steaming durations dramatically alter the structure of Polygonatum cyrtonema polysaccharides (PCPs). This study aimed to compare characteristics of digestion, absorption, and fermentation by gut microbiota across four representative PCPs from different steaming durations (0, 4, 8, and 12 h), each with unique molecular weights and monosaccharide profiles. Chemical composition of the four PCPs was analyzed. Digestibility was evaluated using an in vitro saliva-gastrointestinal digestion model. Absorption characteristics were assessed with a Caco-2 monolayer model, and impacts on gut microbiota composition and short chain fatty acid (SCFA) levels were analyzed using in vitro fermentation with human gut microbiota. Longer steaming durations altered the chemical profiles of PCPs, reducing carbohydrate content (84.87-49.58%) and increasing levels of uronic acid (13.99-19.61%), protein (1.07-5.43%), and polyphenols (0.05-2.75%). Four PCPs were unaffected by saliva digestion but showed enhanced gastrointestinal digestibility, with reducing sugar content rising from 4.06% (P0) to 38.5% (P12). The four PCPs showed varying absorption characteristics, with P0 having the highest permeability coefficient value of 9.59 × 10-8 cm/s. However, all PCPs exhibited poor permeability, favoring gut microbiota fermentation. The four PCPs altered gut microbiota composition and elevated SCFA production, but levels declined progressively with longer steaming durations. All PCPs significantly increased the abundance of Bacteroidota, Firmicutes, and Actinobacteriota, making them the dominant bacterial phyla. Additionally, all PCPs significantly increased the abundance of Bifidobacterium, Prevotella, and Faecalibacterium compared to the control group, which, along with Bacteroides, became the dominant microbiota. Increasing the steaming duration led to a reduction in Prevotella levels, with PCPs from raw rhizomes showing the highest relative abundance at 24.90%. PCPs from moderately steamed rhizomes (4 h) led to a significant rise in Faecalibacterium (7.73%) among four PCPs. P8 and P12, derived from extensively steamed rhizomes (≥8 h), exhibited similar gut microbiota compositions, with significantly higher relative abundances of Bacteroides (20.23-20.30%) and Bifidobacterium (21.05-21.51%) compared to P0 and P4. This research highlights the importance of adjusting steaming durations to maximize the probiotic potential of P. cyrtonema polysaccharides, enhancing their effectiveness in modulating gut microbiota and SCFA levels.

In vivo absorption, in vitro digestion, and fecal fermentation properties of non-starch polysaccharides from Chinese chestnut kernels and their effects on human gut microbiota

Non-starch polysaccharides are major bioactive components in chestnuts, and can serve as water-soluble polysaccharides with potential prebiotic properties. This study aims to establish an in vitro digestion and fermentation model to reveal the digestive and fermentative characteristics of Non-starch polysaccharides from chestnut kernels (NSPCK). The results indicated that under simulated digestion, NSPCK was partially digested in gastric juice but remained significantly undigested in saliva and intestinal juice, demonstrating considerable resilience against hydrolysis. After digestion, NSPCK still exhibited stable rough, lamellar, and porous structure and maintained strong antioxidant capacity. Animal experiments revealed positive effects of NSPCK on blood lipid level, and colon tissue of mice. Moreover, NSPCK enhanced the accumulation of short-chain fatty acids during fermentation, particularly acetic acid, propionic acid, and butyric acid. Furthermore, NSPCK intervention increased the abundance of beneficial bacteria such as Lactobacillus and Bifidobacterium, and at the same time reduced that of harmful bacteria such as Enterococcus.

PSXIII-3 Regrowth interval and propionic acid effects on warm-season grass silage nutritive value and fermentation characteristics

Abstract Warm-season perennial grass species are the main forages preserved as silage or haylage by livestock producers in Florida; however, the nutritive value and silage fermentation parameters are often less than desirable. The objective of this study was to investigate the effects of regrowth interval, propionic acid, and forage species on silage nutritive value and fermentation parameters. The study was conducted in Ona, FL in July and August 2021 and 2022. Treatments were the factorial combination of three forage species [Jiggs bermudagrass (Cynodon dactylon L.), ‘Camello’ brachiariagrass (Urochloa spp.), or Spain guineagrass (Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs)], two regrowth intervals (3 or 6 wk), and propionic acid [0.5% or 0 (control)], distributed in a randomized complete block design with 4 replicates. Forage was harvested and immediately packed into a mini-silo at a density of approximately 190 kg DM/m3. Camello and Spain had less DM (24 vs. 30%; P < 0.01), CP (8.0 vs. 10.7%; P < 0.01), but greater NDF (70 vs. 68%; P < 0.01), ADF (41 vs. 38%; P < 0.01), and in vitro digestible OM concentration (57 vs. 52%; P = 0.04) than Jiggs. There were no differences in fermentation characteristics among species. Forage harvested at 3-wk regrowth interval had less DM (24 vs. 29%; P < 0.01), NDF (68 vs. 71%; P < 0.01), ADF (38 vs. 40%; P < 0.01) but greater CP (10.8 vs. 8.3%; P < 0.01) and in vitro digestible OM (56 vs. 52%; P = 0.03) than 6 wk. There was no effect (P > 0.05) of regrowth interval on fermentation characteristics. Forage treated with propionic acid had greater DM (27 vs. 25%; P < 0.01), CP (9.6 vs. 9.0%; P < 0.01), lactic acid (4.3 vs. 3.1%; P < 0.01), and propionic acid concentrations (1.8 vs 0.1%; P < 0.01) but decreased pH (4.2 vs. 4.6; P < 0.01), ammonia (12 vs. 18% CP; P < 0.01), acetic acid (1.5 vs. 2.0%; P < 0.01), and butyric acid concentrations (0.2 vs. 1.5%; P < 0.01). Propionic acid affected bacterial population abundance by decreasing Clostridium (0.6 vs. 5.3%; P < 0.01) and Enterobacteria (3.0 vs. 11.1%; P < 0.01) and increasing Lactobacillus (45.0 vs. 32.7%; P = 0.04) and Bacillus (0.35 vs. 0.15%; P < 0.01). Forage species and regrowth interval were influential on silage nutritive value while propionic acid improved fermentation characteristics.

PSVIII-8 The impact of foliar fungicide application on barley silage fermentation characteristics and performance of lactating dairy cows

Abstract Forages are an important component in dairy cow diets and barley silage is the primary forage source in western Canada and parts of the USA. Foliar fungal diseases can infect barley, thereby causing leaf damage and a loss of yield and quality. The objectives were to determine the effects of foliar fungicide application on two barley forage varieties, one resistant (CDC Fraser) and the other susceptible (Claymore) to foliar fungal disease, on silage ensiling characteristics and feed intake, milk production and composition, ruminal pH, and nitrogen (N) balance in dairy cows. Multiparous Holstein cows [n = 12; mean (ays in milk (DIM) = 40 ± 17; mean body weight (BW) = 720 ± 26 kg] at the start of the experiment) were used in a replicated 4 × 4 Latin square design with a 2 × 2 factorial arrangement of dietary treatments. Experimental periods were 25 d, with 18 d of dietary adaptation and 7 d of sample and data collection. Test diets were: 1) fungicide-treated Claymore silage (CF); 2) untreated Claymore silage (CNF); 3) fungicide-treated CDC Fraser silage (FF); and 4) untreated CDC Fraser silage (FNF) as the major source of forage. Forage yields were 1.86 (FNF), 1.46 (CNF), 1.17 (FF), and 1.35 (CF) t dry matter (DM)/ha, likely reflective of the low rainfall during the growing season. Experimental silages were similar in crude protein (mean = 14.0%; DM basis), ammonia (mean = 1.95%), and total volatile fatty acid (mean = 9.25%) concentrations. CDC Fraser silage had greater lactic acid concentration (P < 0.001) but decreased pH (P = 0.01) and acetic acid concentration (P < 0.01) than Claymore silage. Silage aNDF contents (DM %) were similar in FF and FNF, but greater in CNF than CF (interaction; P < 0.05). Without fungicide application, barley variety had no effect on silage starch content (DM %), whereas with fungicide application, Claymore had a greater silage starch content than CDC Fraser (interaction; P < 0.05). Dry matter intake, milk yield, and milk composition were unaffected by diet (P > 0.05). Total tract nutrient digestibility was unaffected by diet (P > 0.05). Intake of N, and urinary and fecal N excretion, total N excretion, milk N, and apparent N balance (expressed as g/d or % of N intake) were unaffected by diet (P > 0.05). Ruminal short-chain fatty acid (SCFA) concentrations and pH were unaffected by diet (P > 0.05); however, total SCFA concentration was similar in CF and CNF but was greater in FNF than FF (interaction; P < 0.05). Valerate concentration was similar in FF and FNF but greater in CF than CNF (interaction; P < 0.05). Foliar fungicide application on barley, regardless of variety susceptibility to fungal diseases, did not negatively affect silage quality or dairy cow performance.

Effect of Blending Cashew Apple (Anacardium occidentale L.) and Aonla (Emblica officinalis Gaertn.) Juice on Fermentation of Wine

A Completely Randomized Design (CRD) was employed to assess nine different treatment combinations, varying in juice ratios and fermentation conditions. The study aimed to evaluate the effects of blending cashew apple and aonla juices on the quality and fermentation characteristics of the resulting wine. While studying the chemical composition of cashew apple and aonla juice, cashew apple juice had a maximum value for T.S.S., reducing sugars, total sugars and pH. Aonla aonla juice had a maximum value for titratable acidity, ascorbic acid and tannin content. The T.S.S. of must was adjusted to 24 ºBrix and pH kept natural. The T.S.S. and pH was found to be decreased during fermentation of must. The treatment T5 i.e. 60 % cashew apple: 40 % aonla juice (6.13 ºBrix) recorded lowest T.S.S. and T9 i.e. 20 % cashew apple: 80 % aonla juice (10.53 ºBrix) recorded highest T.S.S. at 12th day of fermentation. The lowest pH recorded in treatment T9 i.e. 20 % cashew apple: 80 % aonla juice (2.10) and highest recorded in T1 i.e. 100 % cashew apple juice (3.38) at 12th day of fermentation. On the other hand, titratable acidity of must was found to be increased during fermentation of must. The minimum titratable acidity was found in treatment T1 i.e. 100 % cashew apple juice (0.62 %) and maximum was recorded in T9 i.e. 20 % cashew apple: 80 % aonla juice (1.74 %) at 12th day of fermentation. The yeast count increases rapidly until the 3rd day (1524 x 103) and after that yeast count subsequently declined until the fermentation reaches the 12th day (36.07 x 103), irrespective of treatments. At the end of fermentation (12th day) highest yeast count was recorded by treatment T5 i.e. 60 % cashew apple: 40 % aonla juice (60 x 103) and lowest yeast count was recorded by treatment T9 i.e. 20 % cashew apple: 80 % aonla juice (21 x103). Wine recovery from must ranged between 73.86 and 83.20 per cent. As a result, treatment T5 (60 % cashew apple juice: 40 % aonla juice) showed better fermentation among all other treatments.

PSXI-11 In vitro rumen fermentation characteristics of rumen fluid obtained from grain-fed and grass-fed farmed American Bison

Abstract The objective of this pilot study was to examine the impact of diet type on in vitro rumen fermentation characteristics using rumen fluid collected from grain-fed and grass-fed American Bison (Bison bison). Rumen fluid was collected from 6 farmed American Bison at a commercial slaughter facility. At the time of slaughter, 3 grain-fed heifers (< 3 yr) were randomly selected for rumen fluid collection. On a separate day, 3 grass-fed cows (>3 yr) were randomly selected for rumen fluid collection. Rumen fluid was collected from each animal by obtaining rumen contents and filtering the rumen fluid from the digesta. For a given collection day, rumen fluid from the 3 animals was combined with McDougall’s buffering solution to generate rumen fluid buffer solution (RFB). The RFB was added to each pre-weighed digestion vessels (DV) containing no substrate (blanks) or 0.5 g of ground substrate (grain-based diet or forage-based diet). After filling, the DV were capped with one-way valves and incubated for 0, 12, 24, 48, and 72 h. At the end of each incubation period, DV were centrifuged, and supernatant was removed and analyzed for VFA concentrations. The remaining pellet was dried at 60°C for 24 h to determine dry matter digestibility (DMD). Descriptive statistics were used to describe DMD characteristics for rumen fluid collected from bison from each production system. Linear, quadratic, and cubic responses were analyzed for DMD. Linear, quadratic, and cubic contrasts were used to examine DMD over time. In vitro DMD increased quadratically (P < 0.05) for grain-fed bison and linearly (P < 0.05) for grass-fed bison over time. Final 72 h DMD was 84.5% ± 0.05 and 70.0% ± 0.11 for grain-fed and grass-fed bison, respectively. Final molar proportions of acetate, propionate, isobutyrate, and butyrate were 55.3% ± 0.01, 25.8% ± 0.002, 1.9% ± 0.01, and 17.0% ± 0.001 for grain-fed bison and 31.0% ± 0.02, 41.2 ± 0.02, 3.9% ± 0.01, and 23.2% ± 0.01 for grass-fed bison. Molar proportions of all VFA exhibited a cubic response (P < 0.05) over time for rumen fluid collected from both grain-fed and grass-fed bison. These data provide a preliminary insight into in vitro rumen fermentation characteristics of bison from different production systems.

PSIII-7 Effects of Saccharomyces cerevisiae fermentation product on total tract digestibility, ruminal fermentation, and plasma metabolome of beef steers fed a finishing diet

Abstract Saccharomyces cerevisiae fermentation product (SCFP) has been widely studied; however, its mode of action on high-concentrate diets has not been fully elucidated. This study evaluated the impact of SCFP on total tract digestibility, fecal excretions of N, P, Zn, and Cu, rumen fermentation, and plasma metabolome of finishing beef steers. Ruminally cannulated Holstein steers [n = 8; body weight (BW) = 580 ± 29.2 kg] were enrolled in a crossover design study with 25-d treatment periods and a 24-d washout period. Steers were fed ad libitum a finishing diet consisting of 20% corn silage and 80% concentrate (on DM basis). Steers were blocked based on initial BW and randomly assigned to two treatments in period 1 and switched to the other treatment in period 2. The treatments were CON (Control, basal diet only) and SCFP (basal diet top-dressed with 12 gּ steer-1ּ ּ d-1 SCFP, NaturSafe, Diamond V, Cedar Rapids, IA). Feed and fecal samples were collected during d 22 to 24 for determination of digestibility. Blood was collected before morning feeding on d 25. Plasma samples were analyzed for metabolome with liquid chromatography-mass spectrometry (LC-MS). Rumen fluid was collected via the rumen cannula at 0, 4, 8, and 12 h post-morning feeding on d 25 and analyzed for pH, volatile fatty acids (VFA), and NH3-N. Performance and ruminal fermentation characteristics data were analyzed using the GLIMMIX procedure of SAS 9.4. Metabolomic data analysis was conducted with Metaboanalyst 6.0. Supplementing steers with SCFP reduced DMI (10.6 vs. 11.4 kg/d, P = 0.05) without affecting (P > 0.05) average daily gain, feed efficiency, and digestibility of organic matter, crude protein, and neutral detergent fiber. Treatment did not affect (P > 0.10) fecal excretions of N, P, Cu, and Zn. Feeding SCFP increased ruminal pH (6.29 vs. 6.01, P = 0.01), numerically reduced concentrations of NH3-N (5.01 vs 6.25 mM, P = 0.16), and total VFA (96.8 vs. 102.5 mM, P = 0.15). SCFP also reduced the ruminal molar proportion of butyrate (11.2 vs. 12.8 molar %, P = 0.01) and tended to increase those of isobutyrate (1.03 vs. 0.90, molar %, P = 0.06) and isovalerate (2.62 vs. 2.29, molar %, P = 0.10). Supplementation of SCFP enriched (P ≤ 0.05) purine metabolism, amino sugar and nucleotide sugar metabolism, and lysine degradation pathways in the plasma. Additionally, tryptophan metabolism and pyrimidine metabolism pathways tended to be enriched (0.05 < P ≤ 0.10) by SCFP. Our findings indicate that feeding SCFP improved the ruminal pH of finishing cattle, which may be beneficial for preventing subacute ruminal acidosis in feedlot cattle. Additionally, SCFP enriched several important plasma nitrogen metabolism pathways, potentially associated with microbial nitrogen metabolism in the rumen, warranting further research.

PSXIII-19 Levels of multicarbohydrase complexes on digestibility and rumen fermentation characteristics for feedlot cattle

Abstract Feeding exogenous enzymes has the potential to increase the digestibility of nutrients and modify rumen fermentation in diets for feedlot cattle, on the other hand, the effect of the inclusion of corn ethanol co-products on nutrient digestibility is still controversial. We hypothesized that the supplementation of enzyme complex improves nutrient digestibility and increases ruminal pH of feedlot cattle receiving a finishing diet and the inclusion of DFS (corn dry bran/fiber plus distillers solubles) has no effect on rumen fermentation and nutrients digestibility. The objective of this study was to evaluate the use of doses of multicarbohydrase complexes and the inclusion of DFS on nutrient digestibility and rumen fermentation. Ruminally cannulated Nellore steers [n = 30; Initial body weight (BW) = 250 kg] were used in a randomized complete block design in a 2 × 3 factorial arrangement. Factor 1 was defined by the inclusion of DFS [15% or 45% of dry matter (DM)], and factor 2 was the doses of multicarbohydrase complexes (0, 0.75 and 1.0 g/10 kg of DM). The diets contained 8.5% sugar cane bagasse, 44 or 73% ground flint corn, 15 or 45% DFS, 0.5 or 1.5% urea and 2% mineral mix plus monensin with the respective enzyme complex doses. The digestibility assessment was carried out based on the assessment of nutrient consumption (offered and non-consumed feed) and total feces production on d 18 to 22 of the study. Ruminal fluid collection was carried out on d 23 of the study, every 3 h, and samples were analyzed to determine ruminal fluid pH, volatile fatty acids (VFA) proportion and ammonia nitrogen concentration. Orthogonal contrasts were performed to evaluate the effects of enzyme complex doses with a significance level of 5%. Two contrasts were tested to compare: 1) 0 g of enzyme vs. inclusion of enzyme, and 2) 0.75 g of enzyme vs. 1.0 g. There was an interaction (P ≤ 0.05) for protein digestibility. The inclusion of multicarbohydrase complexes increased crude protein (CP) digestibility in diets with 45% DFS, with no effect on diets containing 15% DFS. Feeding the enzyme complex increased (P ≤ 0.05) the ether extract digestibility. Feeding 45 vs 15% DFS had no effect on the digestibility of nutrients (P ≥ 0.05). There was no DFS inclusion and doses of enzymes interaction for ruminal fermentation variables. The DFS inclusion did not affect the VFA and ruminal ammonia; however, the inclusion of 45% DFS increased the ruminal pH (6.40 vs. 6.23). The doses of multicarbohydrase complexes did not affect the ruminal pH, VFA and ammonia concentration; however, decreased the acetate:propionate ratio. In conclusion, the enzyme complex had minor effects on nutrient digestibility but improved rumen fermentation, while feeding 45% DFS in the diet had no effect on nutrient digestibility and increased rumen pH.

PSXII-16 Effect of including sugar cane molasses on rumen fermentation characteristics in young beef finishing heifers

Abstract In ruminant animals, the use of molasses has benefits related to improved voluntary intake and increased production of short-chain fatty acids (SCFA) in the rumen, especially butyrate. Butyrate is closely related to gastrointestinal tract health, as it may contribute to the increase in the absorption area of the ruminal epithelium and improve the utilization of diet components, resulting in improved voluntary intake and immune response capacity in stressful situations, such as weaning. Hence, our objective was to assess the effect of sugar cane molasses on rumen fermentation characteristics in young beef finishing heifers. Newly weaned Nellore × Red Angus heifers (n = 12) averaging 238 ± 5.1 kg body weight (BW), were used. All heifers were housed in individual pens with concrete floors, covered feeders, and drinkers. The basal diet was 50 % concentrate, and consisted of corn silage, sorghum silage, ground corn, soybean meal, urea, and a mineral premix. The diet was provided twice daily at 0700 and 1600 h, allowing up to 10% in orts (as fed). The following treatments were evaluated: control (no addition of powdered molasses) or addition of 50 g/kg of diet [dry matter (DM) basis] of powdered molasses. The experiment lasted for a total of 80 d, including a 14-d adaptation period. On d 68 and 76, rumen fluid samples were collected both before and 4 h after the morning feeding using an oral probe coupled to a vacuum pump. The initial fluid samples were discarded to prevent saliva contamination. The rumen fluid was filtered through four layers of cheesecloth, and then pH was measured. Subsequently, samples were taken and stored in an ultra-freezer (-80°C) for subsequent SCFA analysis. The data were subjected to analysis of variance using the GLM procedure of SAS 9.4 (α = 0.05). Providing molasses increased ruminal pH compared with control heifers (P < 0.032). Adding molasses did not affect SCFA concentration (P > 0.90). Conversely, we detected an effect of molasses on SCFA molar proportion. The molar proportion of both acetate (P < 0.013) and butyrate (P < 0.012) were greater in heifers fed molasses than with controls. On the other hand, dietary molasses addition decreased (P < 0.001). the propionate molar proportion. This resulted in an increased (P < 0.002) acetate-to-propionate ratio in heifers fed diets containing molasses. In conclusion, providing sugar cane molasses enhances rumen fermentation characteristics in young beef finishing heifers.

157 Microbial inoculant effects on limpograss silage

Abstract Warm-season perennial grasses are the main forage sources preserved as silage or haylage by livestock producers in subtropical and tropical regions; however, the nutritive value and silage fermentation parameters are often less than desirable. Microbial inoculants have been used to improve grass silage nutritive value and fermentation characteristics with inconsistent results. The objective of this study was to investigate the effects of a microbial inoculant on nutritive value and fermentation parameters of ‘Gibtuck’ limpograss (Hemarthria altissima) silage. Treatments were silage treated with SiloSolve FC (68.1 billion CFU/g, Lactobacillus lactis and Lactobacillus buchneri) or control (no microbial inoculant) distributed in a complete randomized design with 10 replicates. The inoculant level used was 0.5 g/Mg of forage. The experiment was conducted in Ona, FL in May 2023. Twenty 4 × 4 m plots of established limpograss were harvested at 15-cm stubble height with 58-d regrowth interval. The forage was chopped to a particle size ranging from 10 to 18 mm, placed into mini-silos (PVC pipes with rubber), and sealed immediately. The inoculant was applied with a hand sprayer before ensiling. The silos were opened after 60 d for analysis. There was no difference (P > 0.05) between the inoculant and control treatments on DM concentration (25%), DM recovery (96%), NDF (67%), and NFC concentrations (14%); however, silage treated with inoculant had greater CP (8.5 vs. 8.0%; P = 0.03), IVTD (56 vs. 54%; P = 0.01), and NDFD (53 vs. 51%, P = 0.02) and lesser ADF concentrations (38 vs. 40%; P = 0.02) than control. The inoculant did not affect (P > 0.05) silage pH (4.2) and lactic acid concentrations (1.5%) but resulted in greater acetic acid (2.5 vs. 2.0%; P = 0.01), propionic acid (1.6 vs. 1.0%, P < 0.01), and total acid concentrations (5.6 vs. 5.0%; P = 0.04), and decreased butyric acid (0 vs. 0.2%; P < 0.01), isobutyric acid (0.1 vs. 0.4%; P < 0.01), and NH3-N concentrations (4.4 vs. 5.3% N; P < 0.01). Aerobic stability (140 h), mold (1.1 log cfu/g) and yeast (2.2 log cfu/g) count were not affected (P > 0.05) by the inoculant treatment. At the genus level, there was no difference (P > 0.05) in relative abundance of Lactobacillus (85%), Enterobacter (4.0%), Enterococcus (1.8%), and Weissella (0.2%) between inoculant and control, but silage treated with inoculant had less Clostridium (1.0 vs. 2.3%, P = 0.04), Pediococcus (0.2 vs. 0.3%, P = 0.03) and greater relative abundance of Lactococcus (2.8 vs. 0.5%, P < 0.01) and Bacillus (0.2 vs. 0.1%, P = 0.01). At the species level, the inoculant was effective to increase the relative abundance of Lactococcus lactis (from 0.02 to 0.48, P = 0.002) and Lactobacillus buchneri (from 1.4 to 1.9, P = 0.03). SiloSolve FC is a promising microbial inoculant to be used in warm-season grass silage in subtropical and tropical regions.

22 Effects of trace mineral source and chromium propionate supplementation on rumen fermentation, growth performance, and carcass characteristics in finishing beef steers

Abstract Crossbred beef steers [n = 400; body weight (BW) = 370 ± 8 kg] were used to evaluate the effects of trace mineral (TM) source and chromium propionate (Cr) on rumen fermentation characteristics, plasma glucose and mineral concentrations, performance, and carcass characteristics in feedlot steers fed a steam-flaked corn-based finishing diet. Steers were blocked by initial BW and randomly assigned within block to 1 of 4 treatments (10 steers/pen) with 10 pens per treatment. The experimental design was a randomized complete block design with a 2 x 2 factorial arrangement of treatments. Factors included: 1) TM source [sulfate or hydroxychloride (IntelliBond] Cu, Mn, and Zn TM supplemented at 18, 40, and 90 mg/kg DM, respectively) and 2) with or without supplemental Cr (KemTRACE) at 0.0 or 0.25 mg/kg DM. Steers were individually weighed on d -1 and 0 and every 28 d throughout the experiment. Jugular blood samples and rumen contents were collected from 10 steers per treatment on d 28 and 84 of the experiment for plasma glucose and TM concentration and volatile fatty acid analysis, respectively. On d 154 of the experiment, steers were harvested at a commercial abattoir and carcass data was collected. Data were analyzed on a pen mean basis for a randomized complete block design using PROC MIXED of SAS. There was no TM source by Cr supplementation interactions for any of the response variables measured, therefore only main effects are reported. Overall ADG (P = 0.03) and gain:feed (P = 0.02) were greater in steers receiving supplemental Cr when compared with steers not supplemented with Cr. Hot carcass weight (P = 0.04), dressing percentage (P = 0.01), longissimus muscle area (P = 0.03), and USDA yield grades (P = 0.04) were greater in steers receiving hydroxychloride TM compared with steers receiving sulfate TM. Steers supplemented with Cr had a greater dressing percentage (P = 0.01) and longissimus muscle area (P = 0.04) compared with steers not supplemented with Cr. On d 28 of the experiment, ruminal acetate concentrations were lesser (P = 0.01) and ruminal propionate concentrations tended to be greater (P = 0.12) in steers receiving hydroxychloride TM compared with steers receiving sulfate TM. Steers supplemented with Cr had greater ruminal acetate concentrations (P = 0.04) and plasma glucose concentrations (P = 0.05) on d 28 of the experiment when compared with non-supplemented controls. These data indicate the Cr supplementation and TM source can influence feedlot steer performance, carcass characteristics, and rumen fermentation characteristics.

287 Effects of crude glycerin supplementation of beef cattle grazing wheat pasture on forage intake and characteristics of rumen fermentation

Abstract Crude glycerin (CG), mainly composed of glycerin, is a by-product of biodiesel production. Glycerin can be utilized as a substrate of gluconeogenesis by either rapid fermentation to propionate in the rumen or can be directly absorbed through the rumen epithelial wall, resulting in the conversion to glucose in the liver. Therefore, CG supplementation may increase the energy intake of cattle grazing wheat pasture. Ruminally cannulated Angus-crossbred cows [n = 9; 564.4 ±101.6 kg initial body weight (BW)] grazing wheat pasture were utilized in a split-plot design with the objective of evaluating the effects of CG supplementation and forage maturity on forage intake and rumen fermentation characteristics. Treatment was the main plot, and stage of forage maturity was the subplot. Treatments were unsupplemented control (CON) and crude glycerin supplementation (SUP; 37.2% glycerin, DM basis) dosed at 0.11% BW (DM basis). Supplementation levels correspond to 5% of the diet, assuming forage intake of 2.2% of BW on a DM basis. The stages of wheat maturity pasture were March (MAR; vegetative stage) and April (APR; early reproductive stage). Cows grazed a single wheat pasture and were supplemented directly through the rumen cannula twice daily at 0700 and 1900 h. Forage intake in kg/d and as % of BW was greater (P = 0.04) for SUP than CON. Ruminal pH, ammonia, and VFA concentrations, as well as proportions of VFAs, were not affected by CG supplementation (P ≥ 0.34; Table 1). However, ruminal pH (5.77 and 5.99 ± 0.049) and ammonia concentration (0.67 and 3.37 ± 0.307 mM) were greater, while total VFA concentration (136.3 and 110.8 ± 5.23 mM) was less (P = 0.01) for APR compared with MAR. Acetate, propionate, and butyrate molar proportions, as well as acetate: propionate ratio, were not affected (P ≥ 0.27) by the stage of wheat pasture maturity. Results indicate that crude glycerin used as an ingredient in supplementation strategies for cattle grazing wheat pasture may increase cattle energy intake without negatively affecting forage intake and ruminal fermentation.

488 Evaluation of the newly developed value-added blended fat stimulated feed product (BFSFP): Comparison with commercial protein and energy feeds on invitro fermentation characteristics

Abstract This study aimed to compare the nutritional fractions of a newly developed blended fat stimulated feed product (BFSFP) with traditional feed sources as barley grain and canola meal in terms of DM digestibility, neutral detergent fiber (NDF) digestibility, and volatile fatty acids (VFA) using the in vitro batch culture method. Data were analyzed using “Mixed Procedure” of SAS software (SAS Institute, Inc., 2004) using a Completely Randomized Design (CRD). The CRD model assumption test was carried out using Proc Univariate with Normal and Plot option. Multi treatment comparison was carried out using Tukey’s method. Significance was declared at P < 0.05 and tendency at 0.05 < P < 0.10. In terms of NDF digestibility, the newly developed BFSFP was not significantly different from the commercial protein feed [i.e., canola meal and energy feeds (barley)]. At 6 h of incubation the NDF digestibility was 4.98% while the NDF digestibility of barley was 15.32% and canola meal was 9.70%. Similarly at 48 h of incubation NDF digestibility of BPSFP was 45.95% which was not significantly different from barley feed having digestibility 47.22% and canola meal 45.68%. Moreover, in terms of dry matter digestibility (DMD) the BFSFP was significantly different from commercial barley and canola meal. At 6 h of incubation the dry matter digestibility of BFSFP was 46.31% which was greater than canola meal (42.13%) but less than barley (55.19%) at P > 0.05. However, at 48 h of incubation the BFSFP (73.98%) was significantly less from both canola meal (80.04) and barely (90%) at P > 0.05. In terms of VFA, BFSF had an intermediate acetate proportion (48.89 mol/100 mol) compared with canola meal and barley feed (50.35 and 45.90 mol/100 mol), respectively P > 0.05. Propionate was greater for barley feed (29.39 mol/100 mol) than BFSF and canola meal (25.43 and 23.19), respectively P > 0.05. Butyrate was similar for BFSFP and barley feed (13.00 mol/100 mol) and greater than canola meal (10.97 mol/100 mol) at P > 0.05. BFSFP showed an intermediate total VFA concentration (60.12 mMol/L) compared with barley feed (65.69 mMol/L) and canola meal (56.15 mMol/L) at P > 0.05.

154 Forage intake, digestibility, and ruminal fermentation characteristics of beef cows supplemented with a Bacillus-based probiotic

Abstract The aim of this study was to evaluate the influence of a Bacillus-based probiotic supplementation on intake, digestibility, and ruminal fermentation parameters of beef cows consuming a low-quality forage diet (7.0% CP, 60% NDF, 39% ADF, DM basis). Ruminally fistulated Angus × Hereford cows [n = 15; age = 6.1 ± 1 yr; body weight (BW) = 655 ± 57] were used in two identical complete randomized designs, housed in individual pens with water, and forage intake monitored daily. Treatments consisted of 1) 500 g of protein supplement (dry distillers grain + mineral mix) without probiotic (CON n = 15), and 2) 500 g of protein supplement + 3 g of a probiotic containing Bacillus licheniformis and B. subtilis (BOV; n = 15; 2.2 ×109 CFU of the mixture/g; Bovacillus, Novonesis, Hørsholm, Denmark). Each experimental period lasted 33 d, consisting of 21 d of adaptation, 12 d of collection, and 30 d of wash-out between periods. From d 22 to 26, fecal samples were collected to determine intake and nutrient digestibility using titanium dioxide as an indigestible marker. On d 27, ruminal fluid was collected at h 0 (before feeding), 4, 8, 12, 16, and 20 post-feeding to evaluate short-chain fatty acid (SCFA) and N-NH3 concentration. From d 28 to 32, hay samples (4 g) were fitted in Dracon bags and incubated in the rumen for 0, 12, 24, 48, 72, 96, and 120 h to determine nutrient digestibility. Cows receiving BOV had greater (P < 0.001) dry matter intake compared with the CON group (Table 1). Also, cows supplemented with BOV had greater (P < 0.02) dry matter and protein digestibility and a tendency (P ≤ 0.07) for greater NDF and ADF forage digestibility compared with CON. A tendency was also detected (P = 0.09) for the degradability of forage dry matter, which was improved in BOV vs. CON. No effects were observed on rumen fermentation characteristics (P ≥ 0.14; Table 2).). In conclusion, adding bacillus-based probiotics enhanced the intake, nutritional digestibility, and degradability of beef cows fed medium-quality forage diets.

483 DMI, gastrointestinal tract fermentation and permeability, and white blood cell responses in beef heifers provided post-ruminal yeast cell wall extract following feed restriction

Abstract The objectives of this study were to 1) evaluate gastrointestinal fermentation characteristics and permeability, and white blood cell concentrations as beef heifers recovered from a feed restriction (FR) challenge, and 2) determine whether post-ruminal provision of a yeast cell wall extract (YCW) modulated responses. Ruminally cannulated beef heifers (n = 8) were used in a 2 × 2 crossover design. Treatments (TRT) included an abomasal infusion of a placebo (PLC; maltodextrin) or YCW derived from Saccharomyces cerevisiae (2 g/dose) infused at 0600 and 1800 h. Heifers were subject to 5-d of FR (offering 30% of ad libitum DMI) followed by five 5-d recovery phases (REC1, REC2, REC3, REC4, and REC5). Daily DMI, and rumen, fecal, and blood samples were collected on d 5 of FR, REC1, REC3, and REC5 with an additional collection on d 2 of REC1. Total gastrointestinal and post-ruminal permeability were measured using a ruminal dose of Cr-EDTA and an abomasal dose of Co-EDTA, respectively, during FR, REC1, REC3, and REC5 with concurrent urine collection. Data were analyzed to determine the effects of YCW provision, day, and the 2-way interaction. There were no TRT or TRT×day effects for any variables except DMI (interaction, P = 0.04), where DMI did not differ during the FR challenge; however, heifers provided YCW had a greater increase by REC1 compared with PLC heifers without any means differing. DMI progressively increased from FR, to REC1, REC2, and REC5. Ruminal acetate concentration increased (P < 0.01) from FR (45.4 mmol/L) to REC1 d5 (60.1 mmol/L) and increased further to REC3 (67.3 mmol/L) with no change thereafter (68.3 mmol/L in REC5). Ruminal propionate concentration increased (P < 0.01) from FR (14.5 mmol/L) to REC1 d2 (27.7 mmol/L) and was not different thereafter. Similarly, butyrate concentration increased (P < 0.01) from FR (7.9 mmol/L) to REC1 (d 5; 15.0 mmol/L) and was not different thereafter. Fecal acetate, propionate, and butyrate concentrations were not affected by day (P ≥ 0.12). Total gastrointestinal and post-ruminal permeability were greatest during FR (P < 0.01; 2.6% and 2.2% of the infused marker was excreted in urine, respectively) and decreased to 1.6% and 1.1%, respectively, in REC3 followed by an increase in REC5 for total (2.0% of infused) but not post-ruminal (1.0% of infused) permeability. The concentration of neutrophils (P < 0.01) was greatest on REC1 d2 (4.84 ×106 μmol/mL) and eosinophil concentration (P < 0.01) was greatest during FR (0.53 ×106 μmol/mL), least on d 2 of REC1 and increased on d 5 of REC1 but was not different thereafter. WBC (P < 0.01) gradually decreased (P = 0.02) from FR and REC1 d2 to REC3 and REC5. Post-ruminal provision of YCW may accelerate increases in DMI early in the recovery from FR, yet treatment did not modulate ruminal or fecal SCFA, blood concentrations, or gastrointestinal permeability.