Volatile Fatty Acid Profile Research Articles

A growing-finishing diet formulated to reduce the soybean meal does not compromise the growth performance, health, behaviour and gut health of Italian heavy pigs

Soy contributes to the environmental impact of Italian pork production. This study aimed to evaluate the effect of a reduced soybean meal (SBM) and crude protein (CP) finishing diet on growth performance, health, behaviour and gut health of Italian heavy pigs. 1920 pigs (35.6 kg body weight; (BW)) balanced by sex and BW were assigned to the control diet (CO), or the treated diet (TRT) formulated by reducing SBM by 31%, 67% and 69% (replaced by pea and sunflower meal) in 3 feeding phases, respectively, and 1.2% CP in the third phase. 251 pigs were individually weighed at d11, d94 and d181. Feed intake (FI), behavioural indices and air gases at pen-level were monitored monthly. Faecal samples (20/pigs/group) for microbiota, ammonia and volatile fatty acids (VFAs) and hair for stress biomarkers were collected. Diet did not affect final BW, faecal ammonia, cortisol and dehydroepiandrosterone. From d11–d94, the CO group had higher gain to feed (G:F) (p = .007), favourable faecal VFAs profile and a lower environmental ammonia (p < .0001). From d10–d181, the TRT diet increased the ADG (p = .04) and G:F (p = .01), reduced FI (p < .0001) and the lesions score index at d102 (p = .03) and promoted Methanobrevibacter (d94; padj. = 0.013) and Clostridium sensu stricto (d181; padj. = 0.001). Overall, the TRT diet combined with the stress of the transport and acclimatisation to the farm may limit the growth of pigs in the initial period, but it can increase their growth in the long term. Concluding, replacing 56% of SBM with sustainable alternatives seems promising for heavy pig.

Bioefficiency of microencapsulated hemp leaf phytonutrient-based extracts to enhance in vitro rumen fermentation and mitigate methane production.

The objective was to assess the supplementation with microencapsulation of hemp leaf extract (mHLE) utilized as a rumen enhancer on in vitro rumen fermentation and to enhance the bioavailability of active compounds for antimicrobial action, particularly in protozoa and methanogen populations. The feed treatments were totally randomized in the experimental design, with different levels of mHLE diet supplemented at 0, 4, 6 and 8% of total DM substrate and added to an R:C ratio of 60:40. During fermentation, gas kinetics production, nutrient degradability, ammonia nitrogen concentration, volatile fatty acid (VFA) profiles, methane production, and the microbial population were measured. The supplemented treatment at 6% of total DM substrate affected reductions in gas kinetics, cumulative gas production, and volatile fatty acid profiles, especially the acetate and acetate to propionate ratio. Whereas propionate proportion and total volatile fatty acid concentration were enhanced depending on the increase of nutrients in vitro dry matter degradability (IVDMD) after 12 h of post-fermentation at a R:C ratio of 60:40 (P < 0.05). Consequently, mHLE addition resulted in optimal ruminal pH and increased nutrient degradability, followed by ammonia nitrogen concentrations (P < 0.05), which were enhanced by dominant cellulolytic bacteria, particularly Ruminococcus albus and Ruminococcus flavefaciens, which showed the highest growth rates in the rumen ecology. Therefore, mHLE, a rich phytonutrient feed additive, affected the methanogen population, reduced the calculated methane production and can be a potential supplement in the ruminant diet.

Effects of Formaldehyde-Treated Feed on Rumen Metabolism and Blood Biochemistry in Lambs: A Review

This review evaluates the impact of formaldehyde treatment on feed for lambs, focusing on its effects on rumen metabolism and blood biochemical indicators. Formaldehyde is commonly used as a feed additive to improve nutritional efficiency and preserve feed quality. This review synthesizes data from various studies to assess how formaldehyde-treated feed influences rumen fermentation parameters, including volatile fatty acid (VFA) production, rumen pH, and microbial activity. Additionally, the review examines the effects of formaldehyde treatment on key blood biochemical markers such as glucose, urea nitrogen, and liver enzymes. Studies indicate that formaldehyde treatment can enhance the stability and digestibility of feed, potentially improving nutrient utilization and overall animal performance. The preservation of protein and reduction in feed spoilage are highlighted as significant benefits, contributing to more consistent rumen function and metabolic efficiency. However, the impact on rumen microbial populations and VFA profiles shows mixed results, with some studies reporting improved microbial efficiency and others noting minimal changes. The review also discusses potential adverse effects, including alterations in blood biochemical parameters. While formaldehyde treatment generally maintains or improves key indicators like blood glucose and protein levels, excessive use may lead to concerns such as elevated urea nitrogen levels and potential liver enzyme disruptions, the review concludes that formaldehyde-treated feed can be a valuable tool in optimizing feed efficiency and lamb health, provided it is used judiciously. Future research is recommended to further elucidate the long-term effects on rumen microbiota and metabolic processes, ensuring balanced benefits without compromising animal welfare.

Effects of Active Dry Yeast Supplementation in In Vitro and In Vivo Nutrient Digestibility, Rumen Fermentation, and Bacterial Community.

This study assessed the impact of active dry yeast (ADY) on nutrient digestibility and rumen fermentation, using both in vitro and in vivo experiments with lambs. In vitro, ADYs were incubated with rumen fluid and a substrate mixture to assess gas production, pH, volatile fatty acid (VFA) profiles, and lactate concentration. In vivo, Hu lambs were randomly assigned to five dietary treatments: a control group and four groups receiving one of two dosages of either Vistacell or Procreatin7. Growth performance, nutrient digestibility, rumen fermentation parameters, and bacterial community composition were measured. Pro enhanced the propionate molar proportion while it decreased the n-butyrate molar proportion. Vis reduced the lactate concentration in vitro. In the in vivo experiment, Vis increased the propionate molar proportion and the Succinivibrionaceae_UCG-001 abundance while it decreased the n-butyrate molar proportion and the Lachnospiraceae_ND3007 abundance. Additionally, Vis showed a greater impact on improving the NDF digestibility and total VFA concentration in vivo compared to Pro. Overall, the effects of ADYs on rumen fermentation were found to vary depending on the specific ADY used, with Vis being the most suitable for lamb growth. It was observed that Vis promoted propionate fermentation and Succinivibrionaceae_UCG-001 abundance at the expense of reduced n-butyrate fermentation and Lachnospiraceae_ND3007 abundance. Importantly, differences were noted between the outcomes of the in vitro and in vivo experiments concerning the effects of ADYs on rumen fermentation, highlighting the need for caution when generalizing batch culture results to the in vivo effects of ADYs.

Assessing the potential of olive mill solid waste as feedstock for methane and volatile fatty acids production via anaerobic bioprocesses

The extensive production of olive mill solid waste (OMSW) from olive oil industry in the Mediterranean basin claims effective treatments and valorization strategies. This study aims to elucidate the potential of anaerobic digestion (AD) and anaerobic fermentation (AF) to convert pre-treated OMSW into biogas (CH4) and volatile fatty acids (VFA), respectively. The two thermal treatment conditions (65 °C and 180 °C) that are being implemented in the industry that manages the OMSW were tested. Comparing the two treatments aims to demonstrate the influence on the AD process of the degree of solubilization and degradation of the metabolites produced from the same substrate. AD of OMSW treated at low-temperature (65 °C) exhibited similar methane yields (195 ± 8 mL CH4/g volatile solid (VS)) to raw OMSW. AD of the solid phase (SP) after high-temperature treatment with acid addition at 180 °C resulted in methane yields comparable to raw OMSW while the liquid phase (LP) exhibited low methane yields (85 ± 10 mL CH4/g VS). Nevertheless, LP/180 °C exhibited the highest VFA bioconversion at 27.6 %, compared to less than 10 % for SP/180 ºC, SP/65 °C, and raw OMSW. The VFA profile showed notable variations with thermal treatment temperatures. Propionic acid dominated at SP/65 °C, while acetic acid became the primary VFA at 180 °C. Furthermore, significant degradation rates of phenolic compounds and furans were observed during the final day of both anaerobic processes. Overall, these findings suggest that AD is more suitable for raw OMSW, treated at low temperature and SP at high temperature, while AF offers a promising alternative for high-temperature-treated LP.

Microbial community dynamics and volatile fatty acid production during anaerobic digestion of microaerated food waste under different organic loadings

This study examined the effects of microaeration pretreatment and varying organic loading rates (OLRs) on volatile fatty acids (VFAs) production from food waste (FW) via anaerobic digestion process. FW was pretreated with 6 mL O2/g VS and digested at OLRs ranging from 10 to 25 g/L VS. Microaeration pretreatment increased the VFA yield to 7.4 g/L, whereas without pretreatment, it was 5.19 g/L, with butyrate as the dominant VFA (92 % at 25 g/L OLR) due to Firmicutes enrichment. A relatively high OLR initially increased VFA production but later favored propionate without pretreatment. Microbial analysis revealed that aerobic conditions promoted lactic acid bacteria such as Lactobacillus, increasing lactic acid production, whereas anaerobic conditions promoted Prevotella and butyrate producers such as Clostridium, which specialize in acetate and butyrate production. This study highlights that microaeration and an optimal OLR can increase and stabilize VFA yields, modulating the microbial community for tailored VFA profiles that are useful in biofuel and biochemical applications.

Assessing the effects of high-carvacrol oregano oil on rumen microbial fermentation, gas production, and methane production in vitro

The objective of this in vitro study was to assess the effects of high-carvacrol oregano oil (ORE; 50 g/kg oregano oil, 800-802 g/kg carvacrol), on microbial fermentation and CH4 production. In the experiment (a complete randomized block design), treatments included a negative control (CTL, no additive), a positive control (monensin, MON, 10 mg/L), and ORE (20, 40, 80, 120, 200, 160, and 1000 mg/L). Compared with CTL, MON shifted (p &lt; 0.05) volatile fatty acid (VFA) profile from acetate and butyrate to propionate production, thereby reducing (p &lt; 0.05) CH4 production (-26%). Monensin decreased (p &lt; 0.05) NH3 and branched-chain VFA concentrations. Of the doses evaluated, only the highest dose (1000 mg/L) affected ruminal microbial fermentation and CH4 production. At this dose, ORE reduced (p &lt; 0.05) gas production, total VFA, acetate, propionate and NH3 concentrations, and CH4 production (-22%). The reduced gas production and total VFA is an indication of feed digestion inhibition. These results suggest that ORE may decrease CH4 production and improve ruminal N utilization. However, these findings need to be validated in vivo to determine the optimal dose to benefit from the positive effects while avoiding the negative impact of ORE on feed digestion.

Feeding almond hulls to light lambs: Effects on growth performance, digestive utilization and blood metabolites

The effects of including almond hulls (AH) in the concentrate fed to light lambs on animal performance, diet utilization, and blood metabolites. Three isonitrogenous and isoenergetic concentrates were formulated with either 0 (control), 6 (AH6) or 12 (AH12) g of AH per 100 g (fresh matter basis). Thirty Manchega breed lambs (15 males and 15 females; 12.3 ± 0.18 kg body weight (BW)) were distributed into six homogeneous groups according to BW (3 groups of each sex), which were randomly assigned within sex to each experimental concentrate. Lambs were fed concentrate and barley straw ad libitum until reaching about 23.0 kg BW. There were no differences (P ≥ 0.182) between groups in final BW, intake of concentrate and straw, and feed conversion rate. Average daily gain and digestibility of dry matter and crude protein tended (P < 0.10) to decrease by the AH inclusion in the concentrate. Lambs fed AH12 showed greater (P < 0.05) urinary losses than those fed the control concentrate (15.4 and 11.5 g per 100 g of N intake, respectively), despite the similar N intake in all groups. Feeding AH did not affect (P ≥ 0.213) blood concentrations of albumin, globulins, urea, creatinine, glucose, total bilirubin and cholesterol or blood activities of hepatic enzymes. The post-mortem analysis revealed no differences among groups in pH and total volatile fatty acids (VFA) concentrations in the rumen of lambs, but NH3-N concentrations were lower (P < 0.05) in the lambs fed the concentrates with AH. In addition, lambs fed AH12 diet had lower (P < 0.05) molar proportions of propionate and greater (P < 0.05) proportions of butyrate compared with lambs fed control and AH6 concentrate. In general, no concentrate x sex interactions were observed, and sex had no effect on the measured parameters except for some differences in ruminal VFA profile. In conclusion, AH can be included at in light lambs’ concentrate up to 12 g per 100 g of concentrate without impairing animal growth.

Suitability of raw and heat-treated Amaranthus spinosus in broiler diets: Effects on growth performance, meat antioxidant capacity, haemato-biochemical parameters, intestinal histomorphometry, and cecal volatile fatty acid profile

This study aimed to examine the effects of incorporating amaranth (Amaranthus spinosus, either raw or heat-treated) into broiler diets on growth performance, meat antioxidant capacity, haemato-biochemical parameters, intestinal histomorphometry, and cecal volatile fatty acid profile. A total of 210 male Ross 308 broiler chicks were allocated to five dietary treatments in a completely randomized design, with each treatment comprising six replicates of seven birds each. The control group received a diet based on maize and soybean meal, while the remaining dietary groups were formulated to be isonitrogenous and isocaloric to the control, with exact levels of 10% and 20% raw or heat-treated amaranth in the diet. Body weight and feed intake were monitored on days 0, 10, 24, and 39 of the study. On day 39, two birds per replicate were randomly selected for blood sampling, followed by slaughtering for further parameter examination. Incorporating A. spinosus up to 20% in broiler diets had no adverse effect on body weight gain compared to the control. However, higher levels of amaranth led to a negative impact on the feed conversion ratio, attributed to increased feed intake. Furthermore, amaranth supplementation did not negatively influence carcass yield or various organ weights, except for the gizzard, which was heavier in the amaranth-fed groups. Notably, amaranth supplementation reduced abdominal fat, enhanced meat antioxidant status, and had no detrimental effects on blood biochemical or hematological indices. Additionally, amaranth feeding resulted in decreased blood triglyceride levels but had no effect on cholesterol levels. While heat treatment of amaranth did not significantly alter the performance of broiler chickens, it enhanced the beneficial effects of amaranth feeding on the histomorphological features of the duodenum and ileum, and increased blood IgG levels. The cecal volatile fatty acid profile remained largely unaffected by amaranth inclusion, although heat-treated amaranth led to increased levels of branched-chain fatty acids and valerate. Overall, the findings suggest A. spinosus as a promising alternative feed ingredient for broilers when included at 10% of the diet. However, further research is needed to investigate the effect of various amaranth species, processing methods and enzyme supplementation on poultry nutrition to expand its inclusion rate.

Assessing the impact of hatching system and body weight on the growth performance, caecal short-chain fatty acids, and microbiota composition and functionality in broilers

BackgroundVariations in body weight (BW) remain a significant challenge within broiler flocks, despite uniform management practices. Chicken growth traits are influenced by gut microbiota, which are in turn shaped by early-life events like different hatching environments and timing of first feeding. Chicks hatched in hatcheries (HH) experience prolonged feed deprivation, which could adversely impact early microbiota colonization. Conversely, hatching on-farm (HOF) allows early feeding, potentially fostering a more favorable gut environment for beneficial microbial establishment. This study investigates whether BW differences among broilers are linked to the disparities in gut microbiota characteristics and whether hatching systems (HS) impact the initial microbial colonization of broilers differing in BW, which in turn affects their growth patterns. Male Ross-308 chicks, either hatched in a hatchery or on-farm, were categorized into low (LBW) and high (HBW) BW groups on day 7, making a two-factorial design (HS × BW). Production parameters were recorded periodically. On days 7, 14, and 38, cecal volatile fatty acid (VFA) and microbiota composition and function (using 16 S rRNA gene sequencing and PICRUSt2) were examined.ResultsHOF chicks had higher day 1 BW, but HH chicks caught up within first week, with no further HS-related performance differences. The HBW chicks remained heavier attributed to higher feed intake rather than improved feed efficiency. HBW group had higher acetate concentration on day 14, while LBW group exhibited higher isocaproate on day 7 and isobutyrate on days 14 and 38. Microbiota analyses revealed diversity and composition were primarily influenced by BW than by HS, with HS having minimal impact on BW-related microbiota. The HBW group on various growth stages was enriched in VFA-producing bacteria like unclassified Lachnospiraceae, Alistipes and Faecalibacterium, while the LBW group had higher abundances of Lactobacillus, Akkermansia and Escherichia-Shigella. HBW microbiota presented higher predicted functional potential compared to the LBW group, with early colonizers exhibiting greater metabolic activity than late colonizers.ConclusionsDespite differences in hatching conditions, the effects of HS on broiler performance were transient, and barely impacting BW-related microbiota. BW variations among broilers are likely linked to differences in feed intake, VFA profiles, and distinct microbiota compositions and functions.

Harnessing Brewery Spent Grain for Polyhydroxyalkanoate Production

The utility of brewery spent grain (BSG), a byproduct of the beer production process, for the synthesis of polyhydroxyalkanoates (PHAs), is a significant advancement towards sustainable and cost−effective biopolymer production. This paper reviews the upcycling potential of BSG as a substrate for PHA production, utilizing various biotechnological approaches to convert this abundant waste material into high−value biodegradable polymers. Through a comprehensive review of recent studies, we highlight the biochemical composition of BSG and its suitability for microbial fermentation processes. This research delves into different methodologies for PHA production from BSG, including the use of mixed microbial cultures (MMCs) for the synthesis of volatile fatty acids (VFAs), a critical precursor in PHA production, and solid−state fermentation (SSF) techniques. We also examine the optimization of process parameters such as pH, temperature, and microbial concentration through the application of the Doehlert design, revealing the intricate relationships between these factors and their impact on VFA profiles and PHA yields. Additionally, this paper discusses challenges and future perspectives for enhancing the efficiency and economic viability of PHA production from BSG. By harnessing the untapped potential of BSG, this research contributes to the development of a circular economy model, emphasizing waste valorization and the creation of sustainable alternatives to conventional plastics.

Mild alkaline conditions affect digester performance and community dynamics during long-term exposure

This paper examines the adaptive responses of microbial communities to gradual shifts in pH toward the mild alkaline range in anaerobic digestion (AD) systems. The results indicate that a pH of 8.0 serves as a critical upper limit for stable AD operation, beyond which microbial efficiency declines, underscoring the importance of microbial resilience against elevated pH stress. Specifically, hydrolysis genera, e.g. Eubacterium and Anaerobacterium, and syntrophic bacteria were crucial for reactor stability. Fibrobacter had also been shown to play a key role in the accumulation of propionate, thus leading to its dominance in the volatile fatty acid profile throughout the experimental phases. Overall, this investigation revealed the potential adaptability of microbial communities in AD systems to mild alkaline pH shifts, emphasizing the hydrolysis bacteria and syntrophic bacteria as key factors for maintaining metabolic function in elevated pH conditions.

Macleaya cordata extract exhibits some potential as a surrogate antibiotic by improving gastrointestinal epithelial status and humoral response in goats

Macleaya cordata extract (MCE) is a potential replacement for antibiotics. In the current study, effects of MCE on the gastrointestinal health and humoral responses of host animals were explored. A total of 30 weanling goats with similar body weight of 9.15 ± 1.36 kg were randomly allocated into three groups (n = 10 per group): control group (CON group, fed with a basal diet), antibiotic group (Abx group, fed with the basal diet supplemented with 0.18 g/d vancomycin and 0.36 g/d neomycin), and MCE group (fed with the basal diet supplemented with 5 g/d MCE), for three weeks. Results showed that antibiotic addition decreased the height and area of rumen papillae, ruminal mucosa Toll-like receptor 8 (TLR8), interleukin-8 (IL-8) and interleukin-1β (IL-1β) gene relative expression levels and microbial diversity, altered the volatile fatty acid (VFA) profile in the rumen, and increased monocytes amount and CD4+ T cells percentage in the peripheral blood (P < 0.05) compared to CON group. MCE addition increased the average daily gain, ileal villus height, villus height/crypt depth, and immunoglobulin M (IgM) content in the peripheral blood (P < 0.05) compared to the CON. Additionally, MCE addition decreased the proportion of isobutyric acid in the chyme of the ileum (P = 0.005) compared to the CON group. These results suggest that antibiotic supplementation may suppress the epithelial state and microbial diversity and fermentation in goats, but stimulate cellular response to maintain the growth performance of goats. MCE administration improved the epithelial state and humoral response to promote the growth performance in goats.

PSI-20 Isobutyrate supplementation improved energy and nitrogen digestibility in prepubertal gilts fed a high insoluble, but not soluble, fiber diet

Abstract Isoacids are short, branched-chain volatile fatty acids produced by microbial degradation of branched-chain amino acids. While there is a lack of information on isoacids supplementation in monogastric animals, in ruminants, isoacids are growth factors for cellulolytic bacteria which leads to improved digestibility of fibrous ingredients. The objective was to determine if feeding isoacids to prepubertal gilts could improve digestibility of high fiber diets. Two groups of 45 prepubertal gilts (body weight = 139.10 ± 0.68 kg) were individually housed and allotted to 1 of 9 dietary treatments for a 28-d trial (n = 10 per treatment). Dietary treatments consisted of a 3 × 3 factorial arrangement with factors of diet type [corn-soybean meal (CSBM), CSBM with 40% inclusion of distiller’s dried grains with solubles (DDGS), or CSBM with 40% inclusion of sugar beet pulp (SBP)] and isoacids inclusion [no isoacid (NO), 0.50% inclusion of isobutyrate (IB), or 0.88% inclusion of an isoacid mixture (isobutyrate, 2-methylbutyrate, isovalerate; 1:1:1 ratio; MX). Isobutyrate inclusion was the same between IB and MX diets. Gilts were limit fed approximately 2.2 kg per day. Overall growth performance, apparent total tract digestibility (ATTD) of energy and nitrogen (N), and fecal volatile fatty acids (VFA) profile (d 26) were determined. Average daily feed intake (ADFI) was reduced and gain:feed ratio (GF) was increased in gilts fed DDGS (2.14 ± 0.07 kg/d and 0.20 ± 0.02 kg/kg, respectively) or SBP (2.07 ± 0.07 kg/d and 0.19 ± 0.02 kg/kg, respectively) compared with gilts fed CSBM (2.30 ± 0.07 kg/d and 0.15 ± 0.02 kg/kg, respectively), regardless of isoacids inclusion (P &amp;lt; 0.05). Gilts fed DDGS-IB had increased energy (86.5 vs. 83.5 ± 0.42%) and N (84.7 vs. 81.3 ± 0.85%) ATTD compared with gilts fed DDGS-NO (P &amp;lt; 0.05). Gilts fed CSBM-MX had reduced energy (86.9 vs. 88.3 ± 0.50%) and N (75.4 vs. 78.7 ± 0.39%) ATTD compared with gilts fed CSBM-NO (P &amp;lt; 0.05). Moreover, gilts fed SBP-NO had increased energy (85.9 vs. 83.6 ± 0.44%) ATTD compared with the other groups and increased N (71.8 vs. 67.2 ± 0.51%) ATTD compared with SBP-IB (P &amp;lt; 0.05). Fecal content of isobutyrate was decreased in NO compared with the other groups (2.10 vs. 3.00 ± 0.31 mM/L), while fecal content of heptanoate was increased in MX compared with NO (0.06 vs. 0.03 ± 0.01 mM/L), regardless of diet type (P &amp;lt; 0.05). Gilts fed SBP-MX had increased fecal content of total VFA compared with gilts fed SBP-NO (108.90 vs. 67.60 ± 11.50 mM/L; P &amp;lt; 0.05). These results suggest that IB may positively impact the digestibility of diets with a high content of insoluble fiber.

Use of Cracker Residue in the Diet of Dairy Heifers: Impacts on Animal Health, Ruminal Fatty Acids Profile, Digestibility, Weight Gain, and Economic Viability.

This study determined whether the isomeric or isoenergetic/isoproteic substitution of corn in the diet of Jersey heifers in the rearing phase with cracker residue would impair growth and health, as well as reducing production costs. Fourteen Jersey females in the growth phase were used, separated into two treatments with seven animals in each lot in collective pens. The experiment used 7-month-old animals (169.8 ± 2.89 kg) and lasted for four months. In Experiment I, the animals were divided into two groups: treatment, with the partial replacement of 40% corn with cracker residue, and control, in which the animals consumed the same diet with 100% corn (isometric diet kg for kg). In Experiment II, the animals with a body weight of 200.2 ± 3.85 kg were divided into two groups: Treatment, replacing 100% of the corn with cracker residue, and control, in which the animals consumed an isoprotein and isoenergetic diet but with 100% of the corn in the formulation. The diet consisted of concentrate, Tifton 85 hay, and corn silage, supplied twice a day individually, with animals contained in their feeders by kennels. There was water ad libitum in the bay. Biweekly weighing and monthly blood analysis were performed, totaling four collections per part for hematologic evaluation, carbohydrate, lipid, and protein metabolism variables. At the end of each experiment, ruminal fluid was collected to measure the volatile fatty acid profile, and feces were collected to determine the apparent digestibility coefficient (ADC). Experiments I and II showed no effect of treatment on body weight, weight gain, average daily weight gain, feed intake, and feed efficiency. There was no effect of treatment on leukocyte, erythrocyte, lymphocyte, neutrophil, monocyte, and eosinophil counts, hematocrit, and hemoglobin concentration (p > 0.05). Experiment I showed a difference between groups for the variables albumin, globulin, total proteins, cholesterol, glucose, and urea, which did not happen in Experiment II. In both experiments, a higher ADC of nutrients was found in the treatment group which had cracker residue (p > 0.05). The concentration of volatile fatty acids in Experiment I was higher in the control group, unlike in Experiment II, where the highest concentration was in the treatment group (p > 0.05). Because experiment I had an isometric substitution, the diets had different bromatological composition, which is the probable cause of the difference between groups; this did not happen in experiment II, in which the diets consumed by the animals was isoproteic and isoenergetic. Based on these data we conclude that the substitution of cracker residue in an isomeric or isoenergetic/isoproteic form does not negatively affect weight gain and animal health, as well as reduces the cost of the concentrate, consequently reducing the cost of production of these animals.

Nutritional, ruminal, and metabolic parameters of beef bulls fed high-energy diets as a function of dietary addition of a magnesium oxide blend associated or not with monensin

This study aimed to evaluate the impact of a magnesium oxide blend (MG) and monensin (MON) on the nutritional, ruminal, and metabolic parameters of finishing bulls fed high grain diet. Six ruminally cannulated bulls (542 ± 33.6 kg) were used in a 6 × 6 Latin square design with treatments arranged as a 2 × 3 factorial, with 6 periods of 23 days. The MG was included at 0, 2.5, or 5.0 g/kg of dry matter (DM) - MG0, MG2.5, and MG5.0, respectively, without or with MON (30 mg/kg of DM). During each experimental period, days 1–10 were designated for dietary additive adaptation. Days 11–20 (feeding period), were used to assess DM and nutrient intakes, digestibility, ruminal pH, volatile fatty acids (VFA) profile, and blood parameters. Days 21–23 (corn challenge period), included supplementing all treatments with 2 kg/day of ground corn, replacing 2 kg/day of forage, to observe responses in ruminal pH and DM intake (DMI) in the presence of increased fermentable carbohydrates in the rumen. The ruminal pH increased linearly (P = 0.01) with the MG level during the feeding period. In the corn challenge, bulls fed diets without MON and MG5.0, as well as those fed MON and MG2.5 or MG5.0 showed a marked increase in rumen pH value during the first day. In the feeding period, the DMI was greater (quadratic: P = 0.05) for MG2.5 compared to other tested doses. The DM and nutrient intakes were greater (quadratic: P ≤ 0.05) for the MG2.5 group. Bulls fed MON diets had 0.5 kg lower DM and nutrient intakes than those without MON (P ≤ 0.05). The ruminal and intestinal digestibility of diet compounds did not differ among treatments (P ≥ 0.08). The DM and organic matter (OM) apparent total-tract digestibility tended to be (quadratic: P = 0.06) and were greater (quadratic: P = 0.05) for the MG2.5 group. The microbial crude protein synthesis (MCP) was greater for bulls fed the MG2.5 diet (quadratic: P = 0.03). Bulls fed diets without MON had a lower valeric acid (MON × Time: P = 0.03) and those fed diets without MG had a lower iso-valeric acid (MG × Time: P = 0.03) molar proportion 12 hours post-feeding than 1 hour pre-feeding. Glucose levels increased linearly with MG doses (P < 0.001). In summary, a dosage of 5.0 g/kg of DM of MG promotes a superior response in ruminal pH, whereas beneficial effects on digestive parameters are achieved with 2.5 g/kg of DM. Furthermore, MON and MG showed no significant associative effects.

Novel oxidising feed additives reduce in vitro methane emissions using the rumen simulation technique

Enteric methane (CH4) produced by ruminant livestock is a potent greenhouse gas and represents significant energy loss for the animal. The novel application of oxidising compounds as antimethanogenic agents with future potential to be included in ruminant feeds, was assessed across two separate experiments in this study. Low concentrations of oxidising agents, namely urea hydrogen peroxide (UHP) with and without potassium iodide (KI), and magnesium peroxide (MgO2), were investigated for their effects on CH4 production, total gas production (TGP), volatile fatty acid (VFA) profiles, and nutrient disappearance in vitro using the rumen simulation technique. In both experiments, the in vitro diet consisted of 50:50 grass silage:concentrate on a dry matter basis. Treatment concentrations were based on the amount of oxygen delivered and expressed in terms of fold concentration. In Experiment 1, four treatments were tested (Control, 1× UHP + KI, 1× UHP, and 0.5× UHP + KI), and six treatments were assessed in Experiment 2 (Control, 0.5× UHP + KI, 0.5× UHP, 0.25× UHP + KI, 0.25× UHP, and 0.12× MgO2). All treatments in this study had a reducing effect on CH4 parameters. A dose-dependent reduction of TGP and CH4 parameters was observed, where treatments delivering higher levels of oxygen resulted in greater CH4 suppression. 1× UHP + KI reduced TGP by 28 % (p = 0.611), CH4% by 64 % (p = 0.075) and CH4 mmol/g digestible organic matter by 71 % (p = 0.037). 0.12× MgO2 reduced CH4 volume by 25 % (p > 0.05) without affecting any other parameters. Acetate-to-propionate ratios were reduced by treatments in both experiments (p < 0.01). Molar proportions of acetate and butyrate were reduced, while propionate and valerate were increased in UHP treatments. High concentrations of UHP affected the degradation of neutral detergent fibre in the forage substrate. Future in vitro work should investigate alternative slow-release oxygen sources aimed at prolonging CH4 suppression.

Temporal dynamics of volatile fatty acids profile, methane production, and prokaryotic community in an in vitro rumen fermentation system fed with maize silage.

Anaerobic in vitro fermentation is widely used to simulate rumen kinetics and study the microbiome and metabolite profiling in a controlled lab environment. However, a better understanding of the interplay between the temporal dynamics of fermentation kinetics, metabolic profiles, and microbial composition in in vitro rumen fermentation batch systems is required. To fill that knowledge gap, we conducted three in vitro rumen fermentations with maize silage as the substrate, monitoring total gas production (TGP), dry matter degradability (dDM), and methane (CH4) concentration at 6, 12, 24, 36, and 48 h in each fermentation. At each time point, we collected rumen fluid samples for microbiome analysis and volatile fatty acid (VFA) analysis. Amplicon sequencing of 16S rRNA genes (V4 region) was used to profile the prokaryotic community structure in the rumen during the fermentation process. As the fermentation time increased, dDM, TGP, VFA concentrations, CH4 concentration, and yield (mL CH4 per g DM at standard temperature and pressure (STP)) significantly increased. For the dependent variables, CH4 concentration and yield, as well as the independent variables TGP and dDM, polynomial equations were fitted. These equations explained over 85% of the data variability (R2 > 0.85) and suggest that TGP and dDM can be used as predictors to estimate CH4 production in rumen fermentation systems. Microbiome analysis revealed a dominance of Bacteroidota, Cyanobacteria, Desulfobacterota, Euryarchaeota, Fibrobacterota, Firmicutes, Patescibacteria, Proteobacteria, Spirochaetota, and Verrucomicrobiota. Significant temporal variations in Bacteroidota, Campylobacterota, Firmicutes, Proteobacteria, and Spirochaetota were detected. Estimates of alpha diversity based on species richness and the Shannon index showed no variation between fermentation time points. This study demonstrated that the in vitro fermentation characteristics of a given feed type (e.g., maize silage) can be predicted from a few parameters (CH4 concentration and yield, tVFA, acetic acid, and propionic acid) without running the actual in vitro trial if the rumen fluid is collected from similar donor cows. Although the dynamics of the rumen prokaryotes changed remarkably over time and in accordance with the fermentation kinetics, more time points between 0 and 24 h are required to provide more details about the microbial temporal dynamics at the onset of the fermentation.

The effects of rosemary essential oil supplementation on growth performance, rumen flora and antioxidant blood parameters in growing Merino lambs

Thirty-two male growing Merino lambs (78 ± 5 days of age) were used in a 45-day randomized complete block desing to determine the effects of rosemary essential oil (REO) on the growth performance, rumen fermentation, rumen protozoa population, plasma antioxidant enzyme parameters and fecal microbiology. The control group was fed a diet consisting of concentrate and alfalfa hay. The lambs in control group did not receive REO whereas each lamb in experimental groups supplemented with 250 mg/d (R250), 500 mg/d (R500) and 750 mg/d (R750) REO throughout the study. There weren’t statistically differences (P&gt;0.05) in average initial weight, average final weight, live weight gain, average daily gain, daily feed intake, daily dry matter intake and feed conversion ratio between the control and experimental groups. There were also no differences (P&gt;0.05) in the rumen pH, fecal pH, NH3N and rumen volatile fatty acid (VFA) profile of the control and experimental groups. At the end of the study, although the plasma superoxide dismutase (SOD) value increased significantly (P&lt;0.05) in the experimental groups (R500 and R750), glutathione peroxidase (GPX) and catalase values did not differ between REO groups and control. In addition, the fecal microorganism profile did not differ statistically (P&gt;0.05) between the control and experimental groups. The results of this study show that the addition of REO to Merino lamb rations is more effective on antioxidant parameters than on performance parameters and can be used as a natural antioxidant product

Biobased production of volatile fatty acids from brewer’s spent grain: Optimization and insights into the impact of protein extraction on process performance

This study investigates the production of volatile fatty acids (VFAs) from anaerobic digestion of raw brewer’s spent grains (RBSG) and the solid fraction of brewer’s spent grains pretreated by alkaline extraction (PBSG). The variables pH (5−9) and temperature (20–50 ºC) were optimized using Doehlert experimental design. The maximum concentrations of VFAs obtained were 8126.6 ± 108.8 mg L−1 for RBSG and 8005.3 ± 267.9 mg L−1 for PBSG. Protein removal did not affect the fermentative production of VFAs from BSG. However, the type of substrate influenced the VFAs profile and the microbial community. Clostridiaceae and Peptostreptococcaceae were the most abundant members in the reactors fed with raw BSG. On the other hand, Bacteroidaceae and Oscillospiraceae played important roles in the anaerobic digestion of pretreated BSG, accounting for more than 52% of the identified microorganisms. A multiproduct biorefinery with protein removal and subsequent VFAs production had a higher potential revenue (US$ 37,909.00 per ton of RBSG), compared to VFAs production according to a single product model (US$ 258.80 per ton of RBSG) (pH 8 and temperature of 20 ºC). This study provides insights from physicochemical, biological, and engineering perspectives, paving the way for future research focused on utilizing RBSG and PBSG for VFAs production.