Short-chain Volatile Fatty Acids Research Articles

A robust, low-temperature, closed-loop anaerobic system for high-solid mixed farm wastes: advancing agricultural waste management solutions in Canada.

This study investigates the effectiveness of low-temperature (20 ± 1 °C) anaerobic digestion (AD) for two organic multiple farm substrate combinations: Set 1 comprising chicken manure (CM), dairy manure (DM), and waste corn silage (CS) and Set 2 comprising CM, DM, pig manure (PM), and CS. Inoculum adaptation steps were carried out using CM and CM+DM for Set 1 and Set 2, respectively. Over three consecutive operating cycles spanning 245 days with increasing organic loads, 4.3 and 2.8 g VS L-1 d-1 for Sets 1 and 2 during Cycles 1 to 5.1 and 4.6 g VS L-1 d-1for Sets 1 and 2 during Cycle 3, a closed-loop two-stage liquid-solid AD system was employed, with performance assessed via stability ratios of short-chain volatile fatty acids and alkalinity. Results demonstrate that mono-digestion of CM with adapted inoculum yielded the highest biogas production of 424 ± 4 L over 77 days, indicating superior performance by Set 1 during Phase I, whereas a similar performance was observed during Phase 2, where Sets 1 and 2 exhibited highest specific methane yields of 0.233 ± 0.028 and 0.262 ± 0.004 L g-1 VSfed, respectively, over 68 days. Analysis of heavy metal concentrations in digestates revealed a significant decrease compared to initial raw substrate concentrations, highlighting their role as nutrients for microbial growth. This study, the first of its kind, highlights the potential of low-temperature AD systems to manage diverse organic residues/byproducts and offers insights into effective performance monitoring without compromising system integrity.

SMART LIVESTOCK FOR SCIENCE…12 months later

The fourth issue of Slovak Journal of Animal Science 2023 gives to me the opportunity to overview our scientific publishing activity after the first 12 months together. Along four issues, our Journal has been faced with many different aspects of animal farm production, among them mainly circular economy strategy, non-conventional feed resources, and community-based livestock programs. All these different aspects have a common point: boost and develop the livestock farming system, in terms of competitiveness and profitability. Looking at the different articles collected and published during this year, the incorporation of locally available novel feed resource alternatives can promote circular economy concepts, increase food security, and improve sustainable livestock production. By exploiting locally accessible resources, the inclusion of these materials in animal feed nutrition has significant potential to enhance livestock performance, lower production costs, and promote bioeconomy concepts.
 On the other hand, analysis of genomic data is an important resource for the effective management of small and endangered animal populations. The research activity of scientists has deeply been focused on developing breeding programs able to conserve animal biodiversity and monitor animal biodynamics.
 
 In the last Editorial article of 2023, I am going to introduce the contents of the articles collected and published in the fourth issue of 2023 year.
 Formelova et al. performed a study to evaluate the effect of dried hempseed cake (by-product of oil production) supplementation (5% - EG1 and 10% - EG2) to rabbit feed mixture on livestock performances, quality of meat, digestibility of nutrients and animal health status. All obtained data let Authors to recommend the inclusion of hempseed cake up to 10% in rabbit diet without any negative effect on animal welfare, livestock performance and quality of meat.
 Osaiyuwu et al. organized a study to provide useful information for the creation of sustainable breeding programmes and developing a sustainable use and conservation strategy aimed at developing highly producing Muscovy ducks in Nigeria; consequently, increasing the food security index of the nation and source of income for small-scale farmers. In general, the ducks from all seven ecogeographic locations were rather homogeneous than heterogeneous.
 Mekonnen et al., had the prime objective to survey and characterize the husbandry practices of the different indigenous sheep populations. Authors concluded the study claiming a need of feed development, shift to modern husbandry practices, access to veterinary services, indigenous sheep conservation through utilization, control of inbreeding, ram-to-ewe ratio, fattening and castration should be of future attention of farmers and stakeholders.
 Ajayi et al., to justify the use of duckweed as an alternative and novel aquatic-derived fodder in ruminants' feeding strategies, performed preliminary investigation via in vitro gas production technique. The study assessed the nutrient and mineral potential, secondary metabolites and in vitro gas production characteristics of duckweed to estimate the short-chain volatile fatty acids, metabolizable energy, organic matter digestibility and apparent in vitro dry matter degradability. In conclusion, duckweed from earthen fish ponds is fairly degradable in vitro, and the nutrient contents elucidate its forage value for ruminants.
 Editorial Team looks forward to evaluating your submitted contributions and providing all necessary support to Authors in order to best serve animal science and the scientific community, with commitment to research integrity and the highest publishing ethics. Enjoy the reading!

Enhanced biological phosphorus removal from wastewater and dynamics of microbial population in dual PAOs symbiosis system

Low level of volatile fatty acids (VFAs) is a key factor limiting the performance of enhanced biological phosphorus removal (EBPR) by traditional polyphosphate accumulating organisms (PAOs). A newly discovered PAOs capable of fermenting macromolecular organic matter into short-chain VFAs could solve the problem. However, the roles of traditional and fermented PAOs in wastewater treatment processes and the collaboration between functional microorganisms remain unknown. In this study, a sequencing batch reactor (SBR) was operated with alternating anaerobic oxic (An/O) mode to investigate the effect of mixed carbon source ratios, namely, acetate (NaAc):casein hydrolysate (Cas aa) = 4:0, 3:1, 1:1, 1:3 and 0:4, on EBPR performance and microbial community structure. The results showed that the phosphorus removal efficiency remained stable as NaAc was the sole carbon source. When NaAc:Cas aa varied from 3:1 to 1:3, the recovery of system performance took less time compared to the last Run, implying an adaptation of PAOs to Cas aa. Moreover, the anaerobic phosphorus release time was found to increase with the increasing amount of VFAs from Cas aa degradation, indicating the enrichment of fermented bacteria and the utilization of VFAs by traditional PAOs. Increasing the dose of Cas aa also generated more NH4+-N, owing to the reaction of the groups in the amino acids with water, causing a drastic decrease of ammonium removal efficiency from 88.9 % to 15.2 %. The ideal process performance implied that EBPR by dual PAOs synergistic symbiosis occurred in the system with NaAc:Cas aa = 1:1. Meanwhile, the results of 16S ribosomal RNA (16S rRNA) genes-Illumina MiSeq high-throughput sequencing showed that the abundance of traditional PAOs decreased from 22.4 % (4:0) to 11.6 % (1:1) and to 4.9 % (0:4), but fermented PAOs increased from 9.9 % to 19.5 %, then decreased to 17.3 %. Dual PAOs synergistic symbiosis could be of great potential for EBPR in treating low VFAs wastewater.

Chemical composition and in vitro gas production of Brachiaria decumbens harvested at different stages of growth in the hot humid region

The study evaluated the effect of harvesting date on the chemical composition and in vitro gas production of the botanic fractions of Brachiaria decumbens grass. The botanic fractions (leaf, stem and whole plant) of the grass at two maturities (60 and 120 days) in a Completely Randomised Design with factorial arrangement. Samples of botanic fractions at the different harvest dates were chemically analyzed for dry matter (DM), crude protein (CP), fibre concentrations and in vitro gas production (IVGP) was measured at 3, 6, 9, 12, 24, 36, 48, 72 and 96 h to estimate the volume and rate of gas production. Short-chain volatile fatty acids, microbial protein production, in vitro organic matter digestibility, and metabolizable energy were estimated from established models. Organic matter, crude fibre, NDF, ADF and ADL increased (P<0.05) with increasing maturity whereas the reverse was so for CP and ash contents (P<0.05). Significant interactions (P<0.05) between harvest date and plant fraction were present for both ‘b’ and ‘c’ attributable to treatment effects. Potential gas production ‘b’ elicited a negative response for all plant fractions across the two harvest dates as the values decreased linearly. The rate at which the gases were produced ‘c’ also induced a negative response for the leaf and whole fraction but a positive one for the stem fraction. The nutrient composition and gas production characteristics of grasses harvested at day 60 offer a better potential as high quality forage for improved intake and digestibility. The leaf fractions performed relatively better based on the afore-mentioned methods of quality assessment at both maturity periods.

Thermodynamic method for analyzing and optimizing pretreatment/anaerobic digestion systems

This paper builds a quantitative thermodynamic model for the microbial hydrolysis process (MHP, which uses Caldicellulosiruptor bescii at 75°C for pre-digestion) for producing biogas from a 5-10% aqueous suspension of dairy manure (naturally buffered near pH 7.8 by ammonium bicarbonate) by anaerobic digestion with a mix of acetoclastic and syntrophic methanogenesis. Standard Gibbs energy changes were calculated for the major reactions in pre-digestion, for reactions producing H2, acetate, and CO2 in the digester, and for methanogenesis reactions in the digester. The available data limit the study to analyzing reactions in the digester to reactions of short-chain volatile fatty acids anions. Results are presented as curves of ΔrxnG (Gibbs energy change) vs. acetate concentration. The H2(aq) concentration must be above 1.2×10-9 M to get significant syntrophic methanogenesis, i.e., for ΔrxnG to be negative. The results show syntrophic methanogenesis of propionate, butyrate, and valerate slows as acetate concentration increases because hydrogen production also decreases, and consequently, biogas production from syntrophic methanogenesis slows as acetate increases. Bicarbonate also inhibits both acetoclastic and syntrophic methanogenesis but is necessary to prevent acidification (souring) of the digester. At identical steady-state conditions, acetoclastic methanogenesis runs about 1.4 times faster than syntrophic methanogenesis. Because syntrophic methanogenesis produces acetate catabolized by acetoclastic methanogens, both types of methanogens are necessary to maximize biogas production. The culture in the digester is predicted to evolve to optimize the ratio of acetoclastic methanogens to syntrophic methanogens, a condition signaled by a constant, low acetate concentration in the digester effluent. Obtaining volatile solids reduction as high as 75% with MHP requires a feedstock with less than 25% lignin and a culture of acetoclastic methanogens and syntrophic methanogens and their symbiotic bacteria.

Steel slag assists potassium ferrate to improve SCFAs production from anaerobic sludge fermentation

Potassium ferrate (PF) pretreatment in anaerobic sludge and its potential influence mechanisms have received widely attention. This study investigated the coupling effect of PF loading on steel slag (SS) on excess sludge anaerobic fermentation. Results showed that SS loading increase the treatment performance of PF on short chain volatile fatty acids (SCFAs) production from anaerobic fermented sludge. It was showed that the modified PF loaded SS (MPF-SS) promoted the dissolution and release of organic substrates from intracellular to extracellular. Further exploration showed the promotion of PF and MPF-SS exposure to acid production microorganisms was much more than that to acid consumption microorganisms. MPF-SS addition can also effectively reinforce the carbohydrate transport, amino acid metabolism and the key enhanced genes associated with fatty acid biosynthesis pathways. This study fills the knowledge gap about modified PF on sludge treatment and also expands a new perspective for its application for sludge resource recovery.

Analysis of volatile short-chain fatty acids in the gas phase using secondary electrospray ionization coupled to mass spectrometry.

Quantification of metabolites present within exhaled breath is a major challenge for on-line breath analysis. It is also important for gauging the analytical performance, accuracy, reproducibility, reliability, and stability of the measuring technology. Short-chain fatty acids (SCFAs) are of high interest for nutrition and health. Their quantification enables a deep mechanistic understanding of a wide range of biological processes and metabolic pathways, while their high volatility makes them an attractive target for breath analysis. This article reports, for the first time, the development and testing of a modular, dynamic vapor generator for the qualitative and quantitative analysis of volatile SCFAs in the gaseous phase using a secondary electrospray ionization (SESI) source coupled to a high-resolution mass spectrometer. Representative compounds tested included acetic acid, propionic acid, butyric acid, pentanoic acid and hexanoic acid. Gas-phase experiments were performed both in dry and humid (95% relative humidity) conditions from ppt to low ppb concentrations. The results obtained exhibited excellent linearity within the examined concentration range, low limits of detection and quantification down to the lower ppt area. Mixture effects were also investigated and are presented.

Biohythane: a Potential Biofuel of the Future.

Today, the world is becoming more dependent on fossil fuels. The major drawbacks of these non-renewable energy resources include an extreme environmental pollution and an extinction threat. Several technologies including microalgal biodiesel production, biomass gasification, and bioethanol production have been explored for the generation of renewable energy especially, biofuels. One such promising research has been carried out in the generation of biohythane which has the potential to become an alternative fuel to the existing non-renewable ones. It has been reported that biohydrogen can be produced from organic wastes or agricultural feedstocks with the help of acidogens. Dark fermentation can be carried out by acidogens to produce biohydrogen under anaerobic conditions by utilizing lignocellulosic biomass or sugarcane feedstocks in the absence of light. The spent medium contains volatile short-chain fatty acids like acetate, butyrate, and propionate that can serve as substrates for acetogenesis followed by methane biosynthesis by methanogens. Therefore, the sequential two-stage anaerobic digestion (AD) involves a production of biohydrogen followed by the biosynthesis of methane. This combined process is termed as a single eponym "Biohythane" (hydrogen + methane). Several studies have demonstrated about the effectiveness of biofuel, and it is believed to have a greater energy recovery, environmental friendliness, and shorter fermentation time. Biohythane can serve as an alternative future green biofuel and solve the present energy crisis in India as well as the entire world.

Association between morphological manifestations of inflammatory bowel disease and biochemical markers of inflammation

Aim. To determine morphological and morphometric changes in the structure of the mucous membrane of the large intestine and their relationship with the content of short-chain volatile fatty acids and fecal calprotectin in patients with inflammatory bowel disease. Materials and methods. We examined 68 patients with inflammatory bowel disease, including 30 women and 38 men aged 20–66 years, 55 patients were with ulcerative colitis and 13 patients – with Crohn’s disease. Histological examination focused on changes in the mucous membrane of the large intestine. Determination of short-chain volatile fatty acids in feces was performed using gas chromatography. Calprotectin content was measured in fecal samples by enzyme-linked immunosorbent assay. Results. Significant correlations were found between epithelial disruption and changes in crypt architecture, infiltration density, and histological activity. The higher degree of inflammation in patients with severe course was combined with a lower level of tissue nonspecific protection, which was detected by the number of goblet cells, eosinophilic and neutrophilic leukocytes. There was a decrease in the fecal concentration of butyric acid in patients with nonspecific ulcerative colitis and Crohn’s disease compared with controls, but a more significant decrease was observed in patients with severe nonspecific ulcerative colitis. The data have confirmed the association between inflammatory bowel disease and the content of short-chain volatile fatty acids, fecal calprotectin in coprofiltrate, which was evidenced by the presence of correlations between low content of short-chain volatile fatty acids and eosinophilic infiltration (r = -0.412; fecal calprotectin levels and disease severity (r = 0.589; P = 0.001), atrophy (r = 0.458; Р < 0.05), infiltration density (r = 0.434; Р < 0.05). Conclusions. All patients with inflammatory bowel disease are characterized by a specific histological picture, which reflected the different degrees of inflammation. Morphometric parameters more accurately show significant atrophic changes in the mucous membrane of the large intestine. The data have confirmed the association between inflammatory bowel disease and the content of short-chain volatile fatty acids and calprotectin in coprofiltrate.

Nutrient profiling of ruminant feed resources in Ghana

A study was carried out to evaluate the available ruminant feed resources for their nutrient compositions. Two hundred and seventy-eight (278) feed resources were sampled from 27 farms in six regions in Ghana: Ashanti, Brong Ahafo, Greater Accra, Northern, Upper East and Volta. Parameters measured included proximate composition, detergent fibre, and in vitro gas production of the samples. Other parameters such as apparent digestibilities, relative feed values, short-chain volatile fatty acid (SCFAs) content and dry matter intake were estimated using the established models. A Kruskal-Wallis H test was carried out with the nutritional parameters serving as random factors whilst the different feed materials served as fixed factors. The results obtained indicated that root crops and their residues had higher (p < 0.001) CP contents than the other categories of plant-based feed materials whilst cereals and their residues recorded the least CP (p < 0.001). The crude fat content was generally low for all samples, however, the fibre content was high in the cereals, legumes and their residues, grasses, and forbs. The mixed feeds and mashes produced the highest (p < 0.001) quantities of gas after 96 h of incubation (19.38 ml/200 mg DM) and also had a faster rate (p < 0.001) of gas production than the other materials (0.025 ml/h). However, the root crops and their residues were the materials with the highest (p < 0.001) potential gas produced. Digestibilities, SCFA, metabolisable energy and other estimated nutritional attributes were relatively low (p < 0.05) for the varying categories of feed materials except for the mixed feeds and mashes. The study revealed that the nutrient composition and the nutritional value of the feed resources were generally lower than the requirement of ruminant livestock and this may subsequently affect their productivity.

Short-Chain Fatty Acids Modulate Sperm Migration through Olfactory Receptor 51E2 Activity.

The non-orthotopic expression of olfactory receptors (ORs) includes the male reproductive system, and in particular spermatozoa; their active ligands could be essential to sperm chemotaxis and chemical sperm-oocyte communication. OR51E2 expression has been previously reported on sperm cells' surface. It has been demonstrated in different cellular models that olfactory receptor 51E2 (OR51E2) binds volatile short-chain fatty acids (SCFAs) as specific ligands. In the present research, we make use of Western blot, confocal microscopy colocalization analysis, and the calcium-release assay to demonstrate the activation of sperm cells through OR51E2 upon SCFAs stimulus. Moreover, we perform a novel modified swim-up assay to study the involvement of OR51E2/SCFAs in sperm migration. Taking advantage of computer-assisted sperm analysis (CASA system), we determine the kinematics parameters of sperm cells migrating towards SCFAs-enriched medium, revealing that these ligands are able to promote a more linear sperm-cell orientation. Finally, we obtain SCFAs by mass spectrometry in cervico-vaginal mucus and show for the first time that a direct incubation between cervical mucus and sperm cells could promote their activation. This study can shed light on the possible function of chemosensory receptors in successful reproduction activity, laying the foundation for the development of new strategies for the treatment of infertile individuals.

Different feeding strategies can affect growth performance and rumen functions in Gangba sheep as revealed by integrated transcriptome and microbiome analyses.

Due to the harsh environment in the Tibetan Plateau, traditional grazing greatly limits the growth potential of local animals and causes severe ecosystem degradation. This is an urgent issue to be solved, which requires alternative strategies for grazing animals in the Tibetan alpine pastoral livestock systems. This study aimed to investigate the effects of different feeding strategies on growth performance and ruminal microbiota-host interactions in the local breed of sheep (Gangba sheep). Thirty 9-month old Gangba sheep (n = 10 per group) were assigned to natural grazing (G), semi-grazing with supplementation (T), and barn feeding (F) groups (supplementation of concentrate and oat hay) based on body weight. At the end of the experiment (75 d), all sheep were weighed, rumen fluid was obtained from six sheep per group, and ruminal epithelium was obtained from 3 sheep per group. The results showed that: (1) Compared with the G and T groups, the F group significantly increased dry matter intake, average daily gain, and feed conversion ratio of animals. Additionally, Gangba sheep in the F group had higher concentrations of ruminal short-chain volatile fatty acids (VFAs), especially propionate and butyrate (P <0.05) than sheep in the G and T groups. (2) The principal coordinates analysis indicated a significant difference in bacterial composition among different feed strategies. More specifically, the relative abundance of propionate (unidentified F082 and Succiniclasticum) and butyrate-producing (Eubacterium_coprostanoligenes_group) genera were also observed to be increased in the F group, in which unidentified F082 was identified as a differential biomarker among the three groups according to linear discriminant analysis effect size analysis. (3) The dynamics of the rumen epithelial transcriptome revealed that ECM-receptor interactions, focal adhesion, and PI3K-Akt signaling pathways, which are critical in mediating many aspects of cellular functions such as cell proliferation and motility, were upregulated in the F group. In conclusion, under harsh conditions in the Tibetan alpine meadow, barn feeding increased ruminal VFAs concentrations (especially propionate and butyrate), which stimulated gene expression related to cell proliferation in rumen epithelium, appearing to be superior to natural grazing and semi-grazing in gaining body weight of the local Gangba sheep.

Halomonas uses short-chain fatty acids to synthesize polyhydroxyalkanoates

Halomonas can grow on diverse carbon sources. As it can be used for unsterile fermentation under high-salt conditions, it has been applied as a chassis for next-generation industrial biotechnology. Short-chain volatile fatty acids, including acetate, propionate, and butyrate, can be prepared from biomass and are expected to be novel carbon sources for microbial fermentation. Halomonas sp. TD01 and TD08 were subjected to shaking culture with 10-50 g/L butyrate, and they were found to effectively synthesize poly-3-hydroxybutyrate with butyrate as the carbon source. The highest yield of poly-3-hydroxybutyrate was achieved at butyrate concentration of 20 g/L (9.12 g/L and 7.37 g/L, respectively). Butyrate at the concentration > 20 g/L inhibited cell growth, and the yield of poly-3-hydroxybutyrate decreased to < 4 g/L when butyrate concentration was 50 g/L. Moreover, Halomonas sp. TD08 can accumulate the copolymer of 3-hydroxybutyrate and 3-hydroxyvalerate by using propionate and butyrate as carbon sources. However, propionate was toxic to cells. To be specific, when 2 g/L propionate and 20 g/L butyrate were simultaneously provided, cell dry weight and polymer titer were 0.83 g/L and 0.15 g/L, respectively. The addition of glycerol significantly improved cell growth and boosted the copolymer titer to 3.95 g/L, with 3-hydroxyvalerate monomer content of 8.76 mol%. Short-chain volatile fatty acids would be promising carbon sources for the production of polyhydroxyalkanoates by Halomonas.

Effect of industrial processing on the volatiles, enzymes and lipids of wholegrain and rolled oats

The aim of this research was to study the effect of industrial processing stages (kilning, cutting, steaming, rolling and packaging) on the enzymes (lipase and peroxidase), lipids and volatiles of wholegrain and rolled oats. Chemometric data analysis was used to assess the evolution of flavor-related compounds, investigate the relationships between the attributes and select discriminant marker compounds. Oat groats (dehulled oat grain) had significantly (p < 0.05) higher lipase and peroxidase activities, and possessed higher amounts of short-chain volatile fatty acids than the processed oats. The combined effect of kilning and subsequent steaming significantly (p < 0.05) reduced the activity of these enzymes. The use of high temperatures during kilning and steaming triggered the Maillard reaction and Strecker degradation reactions, leading to the formation of odor-active volatile compounds, such as pyrazines, furans and Strecker aldehydes. These compounds are commonly associated with the desirable nutty and toasted aroma of oat-based products. Overall, this study successfully identified key volatile markers and their associated reaction pathways, which can be used to control and optimize the industrial oat processing steps.

Integrated multi-omics analyses reveal the key microbial phylotypes affecting anaerobic digestion performance under ammonia stress

Ammonia inhibition is one of the most common causes of instability during the operation of commercial biogas plants. Here, the sensitivity of different functional bacteria to ammonia stress, the ability of functional bacteria to adapt to ammonia stress, and the key phylotypes affecting anaerobic digestion (AD) performance were studied by evaluating the process performance, active microbiome, and protein expression patterns during endogenous ammonia accumulation using integrated metagenomics and metaproteomics analyses. Acetate metabolism was most sensitive to ammonia stress, and the expression activity of methyl-CoM reductase of Methanothrix was inhibited at relatively low ammonia concentrations, which resulted in the accumulation of acetate and other short-chain volatile fatty acids (VFAs) through feedback effects. As the AD process progressed, the abundance of active Methanosarcina with high ammonia tolerance increased, and the activity of their enzymes related to acetoclastic methanation was significantly up-regulated, which resulted in the complete restoration of acetate metabolism and AD performance. Thus, microbial communities can cope with acetate metabolic repression through self-optimization. In contrast, when the total ammonia nitrogen (TAN) and free ammonia nitrogen (FAN) increased to 4846.95 mg N/L and 337.46 mg N/L, respectively, propionate (and no other VFAs) accumulated in the digester, which was accompanied by a decrease in methane yield by more than 65%. At this time, the abundance of active syntrophic propionate-oxidizing bacteria (SPOB) decreased by 52%, and the expression of key enzymes related to propionate degradation was significantly down-regulated. The proportion of down-regulated differentially expressed proteins in the dominant Pelotomaculum was as high as 94%, indicating the severe suppression of the growth of these functional bacteria as well as their inability to easily acclimate to ammonia stress. Thus, SPOB appeared to be the key microbial phylotypes affecting AD performance under ammonia stress. Ammonia inhibited the methylmalonyl-CoA pathway of Pelotomaculum by inhibiting the expression of succinyl-CoA synthase, which resulted in the suppression of syntrophic propionate oxidation. The results of this study provide new insights into the microbial mechanism of ammonia inhibition and identify the key phylotypes affecting AD performance under ammonia stress. Our findings also shed light on the microbial regulatory targets of nitrogen-rich waste anaerobic digesters.

Cyberlindnera jadinii yeast as a protein source in early- to mid-lactation dairy cow diets: Effects on feed intake, ruminal fermentation, and milk production

We examined the effects of substituting soybean meal with either yeast protein from Cyberlindnera jadinii or barley in concentrate feeds on feed intake, ruminal fermentation products, milk production, and milk composition in Norwegian Red (NRF) dairy cows. The concentrate feeds were prepared in pellet form as soy-based (SBM; where soybean meal is included as a protein ingredient), yeast-based (YEA; soybean meal replaced with yeast protein), or barley-based (BAR; soybean meal replaced with barley). The SBM contained 7.0% soybean meal on a dry matter (DM) basis. This was replaced with yeast protein and barley in the YEA and BAR concentrate feeds, respectively. A total of 48 early- to mid-lactation [days in milk ± standard deviation (SD): 103 ± 33.5 d] NRF cows in their first to fourth parity and with initial milk yield of 32.6 kg (SD = 7.7) were allocated into 3 groups, using a randomized block design, after feeding a common diet [SBM and good-quality grass silage: crude protein (CP) and neutral detergent fiber (NDF) content of 181 and 532 g/kg of DM, respectively] for 14 d (i.e., covariate period). The groups (n = 16) were then fed one of the dietary treatments (SBM, YEA, or BAR) for a period of 56 d (i.e., experimental period). The concentrate feeds were offered in split portions from 3 automatic feeders using electronic identification, with ad libitum access to the same grass silage. Dietary treatments had no effect on daily silage intake, total DM intake, or total NDF intake. Dietary CP intake was lower and starch intake was higher in the BAR group compared with the other groups. Ruminal fluid pH, short-chain volatile fatty acid (VFA) concentrations, acetate-to-propionate ratio, and non-glucogenic to glucogenic VFA ratio were not affected by dietary treatments. No effects of the dietary treatments were observed on body weight change, body condition score change, milk yield, energy-corrected milk yield, milk lactose and fat percentages, or their yields. In conclusion, yeast protein can substitute conventional soybean meal in dairy cow diets without adverse effect on milk production and milk composition, given free access to good-quality grass silage.

A Brief Overview on Probiotics: The Health Friendly Microbes

Probiotics are defined as non-pathogenic live microorganisms that, when administered in adequate amounts, confer health benefits on the host. Association of probiotics with human beings has a lot of history. Well known as 'health-friendly bacteria', they are widely used commercially as a functional food. The popularity of probiotics has gone exponentially high due to an increasing number of clinical trials, supporting their beneficial effects. Several in vivo and in-vitro experimental evidence supports strain-specific and disease-specific probiotic efficacy to prevent and ameliorate antibiotic-associated diarrhoea, traveller's diarrhoea, ulcerative colitis, and many more. Besides, numerous recent studies have reported that probiotics could have a significant effect in alleviating various metabolic, lifestyle and diet-related disorders like obesity, type 2 diabetes, metabolic syndrome, irritable bowel syndrome Strains of Bifidobacterium, Lactobacillus and Saccharomyces boulardii are the most commonly used as probiotics. Safety, efficacy, pathogenicity, infectivity, intrinsic property, virulence factors are to be addressed during probiotic selection. The underlying mechanisms of probiotics effects are still not fully elucidated and have been under intensive research. Numerous diverse, strain-specific probiotic mechanisms have been proposed, which include early colonization of perturbed microbes, competitive exclusion of pathogens, short-chain volatile fatty acid production, alteration of gut pH, immunomodulation and many more. Considering the remarkable influence on human health, probiotics seem to be alluring attractive agents to promote human health conditions and to improve the quality of life against several diseases. This review discusses the current documentation and recent advances on probiotics and their possible health attributes, in scientific literature, focusing on diverse, heterogeneous, and strain-specific mechanisms of action. Randomised human controlled clinical trials are needed to reconfirm its safety and beneficial effects.

Chain elongation may occur in protein mixed-culture fermentation without supplementing electron donor compounds

This study focuses on verifying the occurrence of elongation processes during protein mixed culture fermentation, without the supplementation of electron donor compounds. During casein mixed-culture fermentation at pH 5, it was observed that longer chain volatile fatty acid production increased, which could not be justified by the associated amino acid consumption. Consequently, the occurrence of chain elongation processes was hypothesized. To verify this hypothesis, three casein batch tests, with and without acetic acid initial supplementation, were performed at pH 5. The results suggest that acetic and propionic acids are indeed consumed to selectively generate n-valeric acid through the coupling with electron donor amino acids, whose consumption was further verified through the amino acid analysis. Prolonged simultaneous availability of suitable amino acids and short chain volatile fatty acids and an acid equivalent concentration threshold were identified as key parameters for the occurrence of chain elongation. The supplementation of acetic acid at the beginning of the test changed the selectivity of the elongation process, promoting n-butyric and iso-valeric production. The associated mechanisms were preliminary conceptualized, constituting a first step for further studies on the subject. To the best of our knowledge, this is the first study demonstrating the feasibility of chain elongation processes during protein mixed culture fermentation without electron donor supplementation.

Dietary Enteromorpha Polysaccharide Enhances Intestinal Immune Response, Integrity, and Caecal Microbial Activity of Broiler Chickens.

Marine algae polysaccharides have been shown to regulate various biological activities, such as immune modulation, antioxidant, antidiabetic, and hypolipidemic. However, litter is known about the interaction of these polysaccharides with the gut microbiota. This study aimed to evaluate the effects of marine algae Enteromorpha (Ulva) prolifera polysaccharide (EP) supplementation on growth performance, immune response, and caecal microbiota of broiler chickens. A total of 200 1-day-old Ross-308 broiler chickens were randomly divided into two treatment groups with ten replications of ten chickens in each replication. The dietary treatments consisted of the control group (fed basal diet), and EP group (received diet supplemented with 400 mg EP/kg diet). Results showed that chickens fed EP exhibited significantly higher (P < 0.05) body weight and average daily gain than the chicken-fed basal diet. In addition, significantly longer villus height, shorter crypt depth, and higher villus height to crypt depth ratio were observed in the jejunal and ileal tissues of chickens fed EP. EP supplementation upregulated the mRNA expression of NF-κB, TLR4, MyD88, IL-2, IFN-α, and IL-1β in the ileal and jejunal tissues (P < 0.05). Besides, we observed significantly higher (P < 0.05) short-chain volatile fatty acids (SCFAs) levels in the caecal contents of the EP group than in the control group. Furthermore, 16S-rRNA analysis revealed that EP supplementation altered gut microbiota and caused an abundance shift at the phylum and genus level in broiler chicken. Interestingly, we observed an association between microbiota and SCFAs production. Overall, this study demonstrated that supplementation of diet with EP promotes growth performance, improves intestinal immune response and integrity, and modulates the caecal microbiota of broiler chickens. This study highlighted the application of marine algae polysaccharides as an antibiotic alternative for chickens. Furthermore, it provides insight to develop marine algae polysaccharide-based functional food and therapeutic agent.

Accelerating anaerobic hydrolysis acidification of dairy wastewater in integrated floating-film and activated sludge (IFFAS) by using zero-valent iron (ZVI) composite carriers

Flocculent sludge system usually shows a low treatment efficiency and bad resistance to the feeding shock in the hydrolysis acidification. Integrated floating-film and activated sludge (IFFAS) is a favored system to resist shock, and zero-valent iron (ZVI) is an attractive material to enhance hydrolysis acidification. In this study, an IFFAS equipped with ZVI composite carriers was used to stably increase the degree of acidification (DA) in the anaerobic treatment of dairy wastewater. At the influent organic loading rate of 24.0 kg COD/m3/d with the hydraulic retention time of 3 h, the DA in the reactor filled with ZVI composite carriers was as high as 51.6%, which increased by 9.5% and 7.7%, respectively, comparing with the reactor without biofilm carriers and the reactor filled with polyethylene biofilm carriers. Also, the ZVI composite carriers optimized the biofilm formation and enhanced the activity of protease, pyruvate oxidoreductase, and acetate kinase. Microbial community analysis revealed that hydrolysis acidification bacteria of Comamonas (47.0%) and Petrimonas (2.6%), and acetotrophic methanogens of Methanosarcina (47.1%) and Methanothrix (16.0%) were enriched in the biofilm of ZVI composite carriers. Apart from the main enhancement of mediated interspecies electron transfer, a potential direct interspecies electron transfer also might be established for the presence of Comamonas, Petrimonas, Methanosarcina, and Methanothrix, accelerating the syntrophic production of short-chain volatile fatty acids and methane.