volatile fatty acids
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2022 ◽  
Vol 18 (1) ◽  
Kang Mao ◽  
Guwei Lu ◽  
Yanjiao Li ◽  
Yitian Zang ◽  
Xianghui Zhao ◽  

Abstract Background The fasting and stress associated with road transportation contributes to a lack of energy and a decline in the immune system of beef cattle. Therefore, it is essential for beef cattle to enhance energy reserves before transportation. Creatine pyruvate (CrPyr) is a new multifunctional nutrient that can provide both pyruvate and creatine, which are two intermediate products of energy metabolism. To investigate the effects of transport and rumen-protected (RP)-CrPyr on the blood biochemical parameters and rumen fluid characteristics of beef cattle, twenty male Simmental crossbred cattle (659 ± 16 kg) aged 18 months were randomly allocated to four groups (n = 5) using a 2 × 2 factorial arrangement with two RP-CrPyr supplemental levels (0 or 140 g/d) and two transport treatments (5 min or 12 h): T_CrPyr140, T_CrPyr0, NT_CrPyr140, and NT_CrPyr0. After feeding for 30 days, three cattle per treatment were slaughtered. Results Compared with nontransport, transport decreased the total antioxidant capacity, catalase activity, contents of IgA, interferon γ, interleukin-1β (IL-1β), and IL-6 in serum, and the amounts of total volatile fatty acids (TVFA), acetate, and butyrate in rumen (P < 0.05); increased the serum lipopolysaccharide (LPS) level, contents of rumen LPS and ammonia nitrogen (P < 0.05). RP-CrPyr supplementation decreased the levels of cortisol and LPS in serum and the butyrate concentration in the rumen of beef cattle compared with those in the unsupplemented groups (P < 0.05). RP-CrPyr and transport interaction had a significant effect on the contents of serum tumour necrosis factor-α, IL-6, LPS, ruminal pH, acetate content, and acetate/propionate (P < 0.05). In terms of ruminal bacterial composition, group T_CrPyr0 increased the Prevotella genus abundance compared with group NT_CrPyr0 (P < 0.05), while group T_CrPyr140 increased Firmicutes phylum abundance and decreased Bacteroidetes phylum and genus Prevotella abundance compared with group T_CrPyr0 (P < 0.05). Moreover, Bacteroidetes was positively correlated with serum LPS. Conclusions These results indicated that dietary supplementation with RP-CrPyr might be beneficial to alleviate transport stress by decreasing serum cortisol and LPS levels and promoting the restoration of the rumen natural flora.

2022 ◽  
Vol 8 ◽  
Zhi Yuan Ma ◽  
Ju Wang Zhou ◽  
Si Yu Yi ◽  
Min Wang ◽  
Zhi Liang Tan

In vitro rumen batch culture is a technology to simulate rumen fermentation by inoculating microorganisms from rumen fluids. Although inocula (INO) are commonly derived from fresh rumen fluids, frozen rumen fluids are also employed for the advantages of storing, transporting, and preserving rumen microorganisms. The effects of frozen INO on microbial fermentation and community may be interfered with by substrate type, which has not been reported. This study was designed to test whether rumen fluid treatments (i.e., fresh and frozen) could interact with incubated substrates. A complete block design with fractional arrangement treatment was used to investigate the effects of INO (fresh or frozen rumen fluids) and concentrate-to-forage ratios (C/F, 1:4 or 1:1) on rumen fermentation and microbial community. The effects of increasing C/F were typical, including increased dry matter (DM) degradation and total volatile fatty acids (VFA) concentration (P &lt; 0.001), and decreased acetate to propionate ratio (P = 0.01) and bacterial diversity of richness and evenness (P ≤ 0.005) with especially higher fermentative bacteria such as genus Rikenellaceae_RC, F082, Prevotella, Bacteroidales_BS11, Muribaculaceaege, and Christensenellaceae_R-7 (P ≤ 0.04). Although frozen INO decreased (P &lt; 0.001) DM degradation and altered rumen fermentation with lower (P ≤ 0.01) acetate to propionate ratio and molar proportion of butyrate than fresh INO, typical effects of C/F were independent of INO, as indicated by insignificant INO × C/F interaction on substrate degradation, VFA profile and bacterial community (P ≥ 0.20). In summary, the effect of C/F on fermentation and bacterial diversity is not interfered with by INO type, and frozen INO can be used to distinguish the effect of starch content.

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 555
Monika Zubrowska-Sudol ◽  
Katarzyna Sytek-Szmeichel ◽  
Piotr Krawczyk ◽  
Agnieszka Bisak

This study aimed to evaluate the effects of mechanical disintegration of waste activated sludge (WAS) on full scale anaerobic digestion, considering the possibility of obtaining a positive energy balance. The results showed that an increase in energy density (εL) used in disintegration was accompanied by an increase in the release of organic compounds from sludge (SCOD increased from 211 ± 125 mg O2/L for εL = 0 kJ/L to 6292 ± 2860 mgO2/L for εL = 180 kJ/L). Some of them were volatile fatty acids. The percentage share of WAS subject to disintegration was also documented as a crucial parameter affecting the efficiency of biogas production. An increase in the value of this parameter from 25% to 100%, even at much lower εL used in disintegration (therefore with much smaller amounts of organic compounds released from sludge flocs) resulted in an increase in biogas production. Conducting disintegration of the entire stream of WAS directed to the fermentation tank at εL 30 kJ/L resulted in an increase in biogas production by 14.1%. Such a surplus would allow production of approximately 360 kWh/d net electricity. Mechanical disintegration of thickened WAS therefore may be an economically justifiable strategy for the intensification of anaerobic sludge stabilisation.

2022 ◽  
pp. 75-126
James T. Cullen ◽  
Peadar G. Lawlor ◽  
Gillian E. Gardiner ◽  

The gut microbiome plays a fundamental role in regulating pig health and growth. Understanding the functions performed by the microbiome is vital when considering it as a target to improve pig health and growth, a pursuit driven by the increasing regulation of traditional means of disease control and growth promotion. This chapter explores the structure, diversity and functions of the pig gut microbiome, focusing on the role of the resident bacterial communities. It examines their relationships, interactions, and contributions to the host, ranging from the production of antimicrobial substances and prevention of pathogen colonisation to improvement of nutrient digestibility and the production of volatile fatty acids (VFAs) and vitamins. The chapter also reviews bacterial communication and the antibiotic resistome of the pig gut, outlining how they may be targeted/manipulated to reduce antibiotic resistance and promote improved gut health.

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 195
Elena Rossi ◽  
Simone Becarelli ◽  
Isabella Pecorini ◽  
Simona Di Gregorio ◽  
Renato Iannelli

The aim of this study is to investigate the performance of a pilot-scale plug-flow reactor (PFR) as a biorefinery system to recover chemicals (i.e., volatile fatty acids (VFAs)), and biogas during the dry thermophilic anaerobic digestion (AD) of the organic fraction of municipal solid waste (OFMSW). The effects of the hydraulic retention time (HRT) on both outputs were studied, reducing the parameter from 22 to 16 days. In addition, VFA variation along the PFR was also evaluated to identify a section for a further valorization of VFA-rich digestate stream. A particular focus was dedicated for characterizing the community responsible for the production of VFAs during hydrolysis and acidogenesis. The VFA concentration reached 4421.8 mg/L in a section located before the end of the PFR when the HRT was set to 16 days. Meanwhile, biogas production achieved 145 NLbiogas/d, increasing 2.7 times when compared to the lowest HRT tested. Defluviitoga sp. was the most abundant bacterial genus, contributing to 72.7% of the overall bacterial population. The genus is responsible for the hydrolysis of complex polysaccharides at the inlet and outlet sections since a bimodal distribution of the genus was found. The central zone of the reactor was distinctly characterized by protein degradation, following the same trend of propionate production.

2022 ◽  
Francesco Palumbo ◽  
Giuseppe Bee ◽  
Paolo Trevisi ◽  
Marion Girard

Abstract Hemicelluloses (HC) are polysaccharides constituents of the cell walls of plants. They are fermented in the gut to produce volatile fatty acids (VFA). The present study investigated the effects of decreasing HC level in sow's lactation diet on sow performances, offspring development and milk composition. From 110 days (d) of gestation until weaning (26±0.4 d post-farrowing), 40 Swiss Large White sows were assigned to one of the four dietary treatments: (1) T12 (HC: 120.6 g/kg), (2) T11 (HC: 107.6 g/kg), (3) T9 (HC: 86.4g/kg) and (4) T7 (HC: 71.9 g/kg). Milk was collected at 3 and 17d of lactation. At birth, piglets were divided into two groups according to their birthweight (BtW): normal (N-BtW; BtW > 1.20 kg) or low (L-BtW; BtW ≤ 1.20 kg). Decreased HC levels in the maternal diet linearly increased (P ≤ 0.05) the body weight of L-BtW piglets at two weeks post-weaning and linearly decreased (P ≤ 0.05) diarrhoea incidence and duration in this category. The concentrations of copper, threonine and VFA, as well as the proportion of butyrate, in milk linearly increased (P ≤ 0.05), whereas lactose content linearly decreased (P ≤ 0.05) with decreased HC in the maternal diet. The present study provides evidence that decreasing HC level in sow's lactation diet can positively affect the composition and VFA profile of milk and ultimately favour the growth and health of L-BtW piglets.

Separations ◽  
2022 ◽  
Vol 9 (1) ◽  
pp. 11
Qiuhong Xiang ◽  
Kunlun Yang ◽  
Ziwen Chen ◽  
Manman Li ◽  
Yuanqi Zhang ◽  

In order to improve the production efficiency of volatile fatty acids (VFAs) by anaerobic fermentation of food waste and reduce the cost for the production of organic deicing salt (ODS), ceramic microfiltration (MF) membrane separation was applied in the conventional food waste fermenter to build an anaerobic membrane bioreactor (AnMBR). Results showed that the maximum VFA concentration in AnMBR was up to 55.37 g/L. Due to the fact that the MF membrane could realize in situ separation of VFAs, the recovery of VFAs could reach 95.0%; 66.6% higher than that of traditional fermentation reactors. After the application of the MF membrane, more than 20.0% of soluble COD, 40.0% of proteins, and 50.0% of polysaccharides were retained and more than 90.0% of VFAs could be transferred in a timely fashion in the AnMBR system. In addition, the enrichment effect of the MF membrane enhanced enzymatic activities such as protease, α-Glucosidase and acetate kinase, and increased the abundance of some important bacteria for organic acid generation such as Amphibacter, Peptoniphilus and Halomonas, which made a significant contribution to the yield of VFAs. After concentration, evaporation and crystallization, the melting efficiency of obtained ODS can reach more than 90.0% in chloride salts, which was 112.0% of commercial calcium magnesium acetate (CMA). When compared to chloride salts and CMA, ODS was more environmentally-friendly as it can reduce the corrosion of carbon steel and concrete significantly. This study created a new way of converting food waste into a high-value organic deicing agent, realizing the resource utilization of solid waste and reducing the production cost of organic deicing agents.

2022 ◽  
Vol 4 (1) ◽  
Ana Margarida Pereira ◽  
Maria de Lurdes Nunes Enes Dapkevicius ◽  
Alfredo E. S. Borba

AbstractAgriculture is responsible for a great share of the anthropogenic sources of greenhouse gases that, by warming the earth, threaten its biodiversity. Among greenhouse gas emissions, enteric CH4 from livestock is an important target to slow down climate changes. The CH4 is originated from rumen fermentation and its concentration is affected by several factors, including genetics and nutrition. Ruminants have an extraordinary symbiosis with microorganisms (bacteria, fungi, and protozoa) that ferment otherwise indigestible carbohydrates, from which they obtain energy to grow and continue actively producing, among other products, volatile fatty acids, CO2 and H2. Detrimental ruminal accumulation of H2 is avoided by methanogenesis carried out by Archaea methanogens. Importantly, methanogenesis is not the only H2 sink pathway. In fact, other bacteria can reduce substrates using metabolic hydrogen formed during carbohydrate fermentation, namely propionate production and reductive acetogenesis, thus lowering the CH4 produced. Although the complexity of rumen poses challenges to mitigate CH4 production, the emergence of sequencing techniques that allow the study of microbial communities, gene expression, and metabolome are largely contributing to unravel pathways and key players in the rumen. Indeed, it is now recognized that in vivo emissions of CH4 are correlated to microbial communities, and particularly with the abundance of methanogens, several bacterial groups, and  their genes. The goal of CH4 mitigation is to work in favor of the natural processes, without compromising rumen function, animal health, and productivity. Notwithstanding, the major challenge continues to be the feasibility and affordability of the proposed solutions.

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