Crude Acid Research Articles

Synthesis of 1-Hexanol/Hexyl hexanoate Mixtures from Grape Pomace: Insights on Diesel Engine Performances at High Bio-Blendstock Loadings

The production of oxygenated bio-additives for traditional fuels represents a key challenge due to their depletion in the near-future and their positive contribution to the reduction in environmental pollution. The present study considers the synthesis of 1-hexanol/hexyl hexanoate mixtures, two oxygenated Diesel bio-additives produced through the hydrogenation of hexanoic acid, obtainable from the fermentation of a wide variety of waste biomasses. In our case, crude hexanoic acid was produced through the fermentation of grape pomace, an abundant Italian agrifood waste. Commercial 5 wt% Re/γ-Al2O3 was adopted for the catalytic hydrogenation of crude hexanoic acid, and the support acidity allowed the tuning of the reaction selectivity toward the formation of hexyl hexanoate, instead of 1-hexanol, reaching yields of 40 and 25 mol%, respectively. The effects of each bio-additive on Diesel engine performance and exhaust emissions (soot, nitrogen oxides, carbon monoxide, unburned hydrocarbons) were evaluated, highlighting noteworthy positive effects especially on the reduction in carbon monoxide and soot emissions, if compared with those of Diesel fuel alone. Similar promising performances were achieved by employing Diesel blend mixtures of 1-hexanol/hexyl hexanoate, mimicking typical compositions of the rhenium-catalyzed post-hydrogenation mixtures. Even in such cases, 1-hexanol/hexyl hexanoate mixtures can be blended with commercial Diesel fuel, up to high loadings currently not yet investigated (20 vol%), without altering the engine performances and, again, significantly lowering soot and carbon monoxide emissions by more than 40%. This work highlights the possibility of obtaining such oxygenated bio-additives starting from waste through to a fully sustainable process and proves their beneficial effects on the reduction in exhaust emissions with no changes in engine performance.

Impacts of F18+Escherichia coli on Intestinal Health of Nursery Pigs and Dietary Interventions.

This review focused on the impact of F18+E. coli on pig production and explored nutritional interventions to mitigate its deleterious effects. F18+E. coli is a primary cause of PWD in nursery pigs, resulting in substantial economic losses through diminished feed efficiency, morbidity, and mortality. In summary, the F18+E. coli induces intestinal inflammation with elevated IL6 (60%), IL8 (43%), and TNF-α (28%), disrupting the microbiota and resulting in 14% villus height reduction. Besides the mortality, the compromised intestinal health results in a 20% G:F decrease and a 10% ADFI reduction, ultimately culminating in a 28% ADG decrease. Among nutritional interventions to counter F18+E. coli impacts, zinc glycinate lowered TNF-α (26%) and protein carbonyl (45%) in jejunal mucosa, resulting in a 39% ADG increase. Lactic acid bacteria reduced TNF-α (36%), increasing 51% ADG, whereas Bacillus spp. reduced IL6 (27%), increasing BW (12%). Lactobacillus postbiotic increased BW (14%) and the diversity of beneficial bacteria. Phytobiotics reduced TNF-α (23%) and IL6 (21%), enhancing feed efficiency (37%). Additional interventions, including low crude protein formulation, antibacterial minerals, prebiotics, and organic acids, can be effectively used to combat F18+E. coli infection. These findings collectively underscore a range of effective strategies for managing the challenges posed by F18+E. coli in pig production.

In Vitro Comparative Antimicrobial Potential of Bioactive Crude and Fatty acids Extracted from Abundant Marine Macroalgae, Egypt

In Vitro Comparative Antimicrobial Potential of Bioactive Crude and Fatty acids Extracted from Abundant Marine Macroalgae, Egypt

Effects of Increasing Levels of Total Tannins on Intake, Digestibility, and Balance of Nitrogen, Water, and Energy in Hair Lambs.

This study aims to evaluate the effects of increasing tannin levels from Mimosa tenuiflora hay on the intake, digestibility, and balance of nitrogen (N), water, and energy in hair lambs. Thirty-two Santa Ines lambs, at an average age of 150 days and body weight of 26.75 ± 2.29 kg, were randomly assigned to four treatments in a completely randomized design. The treatments consisted of four diets: a control diet, tannin-free, and three diets with increasing levels of total tannin, 26.2, 52.4, and 78.6 g tannin/kg dry matter (DM). Including the total tannins in the lambs' diet led to a quadratic increase in the intake of nutrients, N-retention (g/day), water intake, water absorption and retention, energy intake, and energy excretion in feces and gases. However, the digestibility of crude protein, neutral and acid detergent fibers, and total carbohydrates decreased. It was observed that there is a correlation between the variable nutrient digestibility and N-ingested and the N-absorbed, N-urinary, and N-retained. However, the N-excreted in feces did not correlate with any of the variables studied. It is recommended to include 33 g/kg DM of total natural tannins from Mimosa tenuiflora hay in the diet of hair lambs, as it improves intake, energy balance, dietary N, and body water composition while reducing the excretion of N-urinary and gas emissions to the environment.

In vitro and in vivo analyses of the nutritive value of native and ensiled partial crop field peas

This study was conducted to determine the effect of ensiling on the nutritive value of partial crop field peas. The field peas were harvested with approximately 500 g dry matter (DM) at a cutting height of 25 cm and ensiled without previous wilting or use of inoculants. In vitro gas production kinetics were determined in ruminal fluid batch cultures. The apparent total tract digestibility of crude nutrients, detergent fibers and gross energy and the content of metabolizable energy and net energy lactation of native and ensiled peas was determined in a digestibility trial with wethers. Microbial nitrogen efficiency was calculated on the basis of allantoin excreted via the urine. The pea silage was characterized by a low pH (4.1) and contained relevant quantities of lactic acid (56.3 g/kg DM) and acetic acid (16.8 g/kg DM). The proportions of crude protein, starch and nitrogen-free extracts were slightly increased in the silage, while the concentrations of fiber fractions decreased. Soluble protein was increased in the silage from 56% to 66% of crude protein due to increasing non-protein nitrogen concentrations. Gas production was higher in ensiled than in native peas (P < 0.001). Apparent digestibility of crude protein and acid ether extract increased in the silage by 3% and 10% points, respectively. Digestibility of crude fiber, neutral detergent fiber and acid detergent fiber decreased by 9%, 6% and 5% points, respectively (P < 0.05). The contents of metabolizable energy and net energy lactation increased by 0.5 and 0.3 MJ/kg DM, respectively (P < 0.05). The microbial nitrogen efficiency tended to be higher in animals that received ensiled partial crop peas (P > 0.05), but strongly depended on individual excretion quantities. In conclusion, ensiling of partial crop field peas with approximately 500 g DM/kg at harvest led to well conserved feed with increased concentrations of nutrients and content of energy.

Biosynthesis of Copper Oxide and Silver Nanoparticles by Bacillus Spores and Evaluation of the Feasibility of Their Use in Antimicrobial Paints.

Modification of paint with nanoparticles (NPs) provides self-cleaning, water/dirt-repellent, and other properties. Therefore, the aim of the present study was to biosynthesize silver (Ag) and copper oxide (CuO) NPs and to prepare NP-modified paint. To this end, AgNPs and CuONPs were biosynthesized using Bacillus atrophaeus spores and commercial and crude dipicolinic acid (DPA) extracted from the spore of this bacterium. The synthesized NPs were characterized using electron microscopy, Fourier-transform infrared (FTIR), X-ray diffraction analysis (XRD), and energy-dispersive X-ray spectroscopy (EDS) methods. A minimum inhibitory concentration (MIC) assay of NPs against Escherichia coli ATCC8739 and Staphylococcus aureus ATCC6538 was carried out. The antibacterial effects of prepared NP-paint complexes were assessed using an optical density (OD) comparison before and after adding metal sheets coated with NP-paint complexes into the nutrient broth medium. Four different types of NPs were synthesized in this research: AgNPs synthesized by spore (A), AgNPs synthesized by commercial DPA (B), AgNPs synthesized by crude DPA (C), and CuONPs synthesized by spore (D). SEM analysis confirmed the spherical shape of NPs. According to the results, NPs A, B, and D showed higher antibacterial activity against S. aureus compared to E. coli. Furthermore, the analysis of the antibacterial effects of NP-paint complexes suggested that paint-NPs A, B, and C displayed higher activity on E. coli compared to S. aureus. Moreover, the antibacterial effect of paint-NP D was significantly lower than other NPs. According to this robust antibacterial effect on pathogenic bacteria, it seems that these NP-paint complexes could be useful in public places such as hospitals, airports, dormitories, schools, and office buildings, where the rate of transmission of infection is high.

How to design a low-cost pilot scale magnetic bioseparation process for protein separation from complex mixtures using in-line process analytics

Magnetic separation is a powerful tool for the integrated capture and purification of biomolecules and cells directly from complex feed media without the need for prior clarification and without the risk of equipment blockage. In this study, we equipped a commercially available rotor–stator high-gradient magnetic separator (RS-HGMS) with in-line analytics of hygienic design (absorbance, conductivity, pH, and flow) and used it for a systematic characterization of the equipment. By combining particle agglomeration and separation studies with residence time analysis, magnetic filter capacity, and particle retention experiments for bare iron oxide nanoparticles (BIONs), we developed a generic RS-HGMS operation protocol optimized for minimal particle carry-over and efficient buffer exchange. To demonstrate the versatility of our approach, we customized this operation protocol for the challenging task of lactoferrin separation from crude acid whey, which serves as an illustrative example in this paper. The modifications involved simple adjustments of pump speed, step duration, and cycle repetition without altering the fundamental principles of our generic approach. In this proof-of-concept, a BIONs carry-over of less than 0.037 g L-1 was achieved in the elution fractions, and the in-line sensors enabled continuous monitoring and documentation of the process, providing valuable data for process optimization and validation. This paper demonstrates how a magnetic separation process can be effortlessly tailored for challenging bioseparation tasks, while emphasizing the importance of implementing continuous in-line process monitoring and data logging. We believe this is an essential step toward the wider adoption of this promising technique in the industry.

Purification of crude terephthalic acid using phosphomolybdic acid supported on MCM-41 and TiO2 photocatalysts

The present research introduces the photocatalytic process for the conversion of 4-carboxybenzaldehyde to terephthalic acid through the synthesis of phosphomolybdic acid (PMo) supported on TiO2 and MCM-41 as the new class of photocatalysts for this application. As synthesized photocatalysts were characterized through XRD, FT-IR, N2 adsorption–desorption, and FESEM-EDS. It was found that the maximum conversion of 4-carboxybenzaldehyde to para-toluic acid was achieved by 25% PMo/TiO2 photocatalyst with a value of 97.85%. To investigate the effect of parameters such as UV irradiation power intensity, temperature, catalyst dosage, and persulfate concentration, Response Surface Methodology (RSM) was used. Finally, the experimental results showed the UV irradiation power intensity of 2.3 W/mL, the temperature of 24 °C, and the concentration ratio of terephthalic acid to persulfate and catalyst of 3.1 mg/mg and 7.2 mg/mg, respectively as the optimum values. At this operating condition, the concentration of 4-carboxybenzaldehyde decreased from 1870 ppm to 40.2 ppm after 90 min.

Investigation of Crystal Size Distribution in Purification of Terephthalic Acid from Polyester Textile Industry Waste by Reactive Crystallization

The purification of terephthalic acid recovered from an alkali-reduction wastewater by reactive crystallization was investigated. The crude terephthalic acid was reacted with sodium hydroxide solution to form a salt of disodium terephthalate, then acidified with sulfuric acid to get the terephthalic acid with higher purity. Effects of time, pH, concentration, and flow rate of secondary feed solutions, temperature, and stirring rate on Crystal Size Distribution (CSD) of terephthalic acid precipitate were investigated. The results showed that CSD was influenced by the concentration of reactants and the pH solution. On the other hand, time, temperature, flow rate of secondary solution, and stirring rate had no significant effects on the CSD, which the mean size of crystals ±3 μm. The mean size of crystals at solution pH 5, 4, and 3 were 6.03, 9.42, and 10.34 μm, respectively; meanwhile, at concentrations of 0.5, 0.3, and 0.1 M, were 7.57, 3.24, and 3.09 μm, respectively. The semi-batch reactive crystallization with double-feeding at constant pH and temperature produced monodispersed crystals. However, this method needs to be carried out more than once for terephthalic acid purification, which is intended for polyethylene terephthalate (PET) polymerization.

7-Geranyloxycinnamic Acid Isolated from Melicope lunu-ankenda Leaves Perturbs Colon Cancer and Breast Cancer Cell Lines' Growth via Induction of Apoptotic Pathway.

Globally, breast cancer is the most prevalent form of cancer in women and there is a need for alternative therapies such as plant-derived compounds with low systemic toxicity and selective toxicity to cancer cells. The aim of this study is to assess the cytotoxicity effects of 7-geranyloxycinnamic acid isolated from leaves of Melicope lunu-ankenda, a traditional medicinal plant, on the human breast cancer cell lines. Dried leaf powder was used for the preparation of different crude extracts using different solvents of increasing order of polarity. The structure of the isolated compound from the petroleum ether extract was elucidated by 1H and 13C NMR, LC-MS, and DIP-MS spectroscopy. The cytotoxic activity of the crude extract and 7-geranyloxycinnamic acid analyzed using MTT assay. Apoptotic analysis was evaluated using Annexin V-PI staining, AO/PI staining, intracellular ROS measurement, and measurement of activities of caspases 3/7, 8, and 9. Crude extracts and the isolated pure compound showed significant cytotoxicity against tested cancer cell lines. 7-geranyloxycinnamic acid was found to exert significant cytotoxic effects against breast cancer cell lines such as the MCF-7 and MDA-MB-231 cell lines. The cytotoxic effects are attributed to its ability to induce apoptosis via accumulation of ROS and activation of caspases in both breast cancer cell lines. The pure compound, 7-geranyloxycinnamic acid isolated from the leaves of M. lunu-ankenda, can exert significant cytotoxic effects against breast cancer cell lines without affecting the normal cells.

Hydrogenation of fatty acids to fatty alcohols over Ni3Fe nanoparticles anchored on TiO2 crystal catalyst: Metal support interaction and mechanism investigation

Catalytic transformation of fatty acids into fatty alcohols is the essential step to produce renewable energy and high-valuable chemicals from waste fatty acids. In this research, a series of Ni3Fe catalysts were synthesized to improve this transformation, specifically that the Ni3Fe anchored on TiO2 surface has performed excellent activity with a high alcohol yield reaching 91.2%. The structure–reactivity relationship between the Ni3Fe nanoparticles on different crystal types of TiO2 (anatase: A-TiO2, rutile: R-TiO2) was investigated. It was found that the as-prepared Ni3Fe/R-TiO2 catalyst showed better catalytic performance than that of Ni3Fe/A-TiO2. Both experimental and density functional theory (DFT) computational results indicated that the interactions between Ni3Fe nanoparticles and R-TiO2 support have highly promoted the formation of oxygen vacancy (Ov), which plays an essential role in CO and HH cleavage, thus promoting the hydrogenation towards fatty alcohols. Furthermore, the catalyst reusability tests showed that Ni3Fe/TiO2 catalyst exhibited good stability over four times recycled and excellent suitability for industrial crude fatty acid conversion.

Integrating Enzyme Evolution and Metabolic Engineering to Improve the Productivity of Γ-Aminobutyric Acid by Whole-Cell Biosynthesis in Escherichia Coli.

γ-Aminobutyric acid (GABA) is used widely in various fields, such as agriculture, food, pharmaceuticals, and biobased chemicals. Based on glutamate decarboxylase (GadBM4) derived from our previous work, three mutants, GadM4-2, GadM4-8, and GadM4-31, were obtained by integrating enzyme evolution and high-throughput screening methods. The GABA productivity obtained through whole-cell bioconversion using recombinant Escherichia coli cells harboring mutant GadBM4-2 was enhanced by 20.27% compared to that of the original GadBM4. Further introduction of the central regulator GadE of the acid resistance system and the enzymes from the deoxyxylulose-5-phosphate-independent pyridoxal 5'-phosphate biosynthesis pathway resulted in a 24.92% improvement in GABA productivity, reaching 76.70 g/L/h without any cofactor addition with a greater than 99% conversion ratio. Finally, when one-step bioconversion was applied for the whole-cell catalysis in a 5 L bioreactor, the titer of GABA reached 307.5 ± 5.94 g/L with a productivity of 61.49 g/L/h by using crude l-glutamic acid (l-Glu) as the substrate. Thus, the biocatalyst constructed above combined with the whole-cell bioconversion method represents an effective approach for industrial GABA production.

Silage quality and bacterial diversity of silages inoculated with Listeria monocytogenes and Lacticaseibacillus paracasei_6714

Introduction: King grass (Cenchrus purpureus (Schumach.) Morrone, syn. Pennisetum purpuphoides) and pineapple peel (Ananas comosus) silages are food alternatives for livestock in conditions of feed shortage. Objective: To describe the dynamics of the microbiota present in king grass and pineapple silage during the fermentation process using next generation sequencing (NGS) and to evaluate the protective effect of Lacticaseibacillus paracasei_6714 as a silage inoculum against Listeria monocytogenes. Methods: We used an unrestricted randomized design to characterize the microbiota present in silages made from king grass harvested 70 days after regrowth and pineapple peel. We inoculated mixtures of grass and peel with L. paracasei_6714 or L. monocytogenes, or both, with a non-inoculated treatment as control. The nutritional and fermentative profile was evaluated after 30 days. After 15 and 30 days of fermentation, we used 16S rRNA analysis to determine the dynamics and diversity of the microbiota in the inoculated and control silages. Result: Dry matter content and digestibility did not differ significantly; however, there were differences in crude protein, pH and organic acids. We obtained 4432 amplicon sequence variants of Proteobacteria, Firmicutes, Bacterioidetes, Actinobacteria, Verrucomicrobia, Planctomycetes and Patescibacteria. The relative abundance of each phylum varied depending on the material and fermentation period. Phylum similarity was over 70 % (but not greater than 50 % with Bray-Curtis at the species level). Conclusion: These bacterial communities seem to have an important role during silage fermentation. Proper management of silage processing can reduce or eliminate pathogenic bacteria.

Determination and Correlation of Vapor–Liquid Equilibria for the Nitric Acid + Water, Nitric Acid + Water + Phosphoric Acid, and Nitric Acid + Water + Phosphoric Acid + Sulfuric Acid System

The wet-process production of phosphoric acid by the nitric acid method is considered as a promising technology with great development prospects due to no production of the byproduct phosphogypsum. However, the traditional nitro-phosphate fertilizer producing process cannot separate nitrogen and phosphorus thoroughly, which limits its applications. The key to solving this problem is to remove nitric acid from the crude phosphoric acid product obtained in the nitric acid wet process by evaporation. Therefore, it is important to measure the vapor–liquid equilibrium (VLE) data of the nitric acid + water + phosphoric acid + sulfuric acid quaternary system under different pressures and concentrations. In this study, the VLE data of the following systems were measured at 10, 20, 40, 60, 80, and 97.4 kPa by the quasi-static ebulliometric method: (1) nitric acid + water; (2) nitric acid + water + phosphoric acid; and (3) nitric acid + water + phosphoric acid + sulfuric acid. The electrolyte non-random two-liquid parameters for the following pairs were correlated with the VLE data by using Aspen Plus as a tool: HNO3-H2O, H3PO4-H2O, HNO3-H3PO4, HNO3-H2SO4, H3PO4-H2SO4, H+[H2PO4]−-H+[NO3]−, H+[NO3]−-H+[HSO4]−, and H+[H2PO4]−-H+[HSO4]−. The obtained VLE data and interaction parameters can provide the basis for the nitric acid method of mother liquor denitrification in the subsequent industry.

Polystyrene Upcycling into Fungal Natural Products and a Biocontrol Agent.

Polystyrene (PS) is one of the most used yet infrequently recycled plastics. Although manufactured on the scale of 300 million tons per year globally, current approaches toward PS degradation are energy- and carbon-inefficient, slow, and/or limited in the value that they reclaim. We recently reported a scalable process to degrade post-consumer polyethylene-containing waste streams into carboxylic diacids. Engineered fungal strains then upgrade these diacids biosynthetically to synthesize pharmacologically active secondary metabolites. Herein, we apply a similar reaction to rapidly convert PS to benzoic acid in high yield. Engineered strains of the filamentous fungus Aspergillus nidulans then biosynthetically upgrade PS-derived crude benzoic acid to the structurally diverse secondary metabolites ergothioneine, pleuromutilin, and mutilin. Further, we expand the catalog of plastic-derived products to include spores of the industrially relevant biocontrol agent Aspergillus flavus Af36 from crude PS-derived benzoic acid.

Feed gap analysis of dual-purpose chicken production in Tanzania: feed quantity and quality limited production

The demand for chicken meat and eggs exceeds what can be produced in Tanzania, largely due to low productivity of the sector. Feed quantity and quality are the major factors determining the potential production and productivity of chickens. The present study explored the yield gap in chicken production in Tanzania and analyses the potential of increased chicken production as a result of closing the feed gaps. The study focused on feed aspects limiting dual-purpose chicken production in semi-intensive and intensive systems. A total of 101 farmers were interviewed using a semistructured questionnaire and the amount of feed provided to chickens per day was quantified. Feed was sampled for laboratory analysis and physical assessments were made of weights of chicken bodies and eggs. The results were compared with the recommendations for improved dual-purpose crossbred chickens, exotic layers, and broilers. The results show that the feeds were offered in insufficient quantity compared with the recommendations for laying hens (125 g/chicken unit/d). Indigenous chickens were fed 111 and 67 while the improved crossbred chickens were fed 118 and 119 g/chicken unit/d under semi-intensive and intensive systems, respectively. Most feeds fed to dual-purpose chickens were of low nutritional quality, particularly lacking in crude protein and essential amino acids in both rearing systems and breeds. Maize bran, sunflower seedcake, and fishmeal were the main sources of energy and protein in the study area. The study findings show that the important feed ingredients: protein sources, essential amino acids, and premixes were expensive, and were not included in formulating compound feeds by most chicken farmers. Of all 101 respondents interviewed, only one was aware of aflatoxin contamination and its effects on animal and human health. All feed samples contained a detectable concentration of aflatoxins and 16% of them exceeded the allowed toxicity thresholds (>20 µg/kg). We highlight the need for a stronger focus on feeding strategies and ensuring the availability of suitable and safe feed formulations.

Optimization of microwave assisted synthesis of activated carbon from biomass waste for sustainable industrial crude wet-phosphoric acid purification

Crude phosphoric acid, generated during industrial wet production, requires careful treatment by different processes to make it acceptable for various agro-industrial applications. The purification of crude phosphoric acid is still challenging and costly at a large scale because of the presence of various organic and inorganic pollutants. The adsorption technique for the purification of crude phosphoric acid suffers from the low sorption rate due to its complexity in terms of chemical composition and low pH. To enhance the sorption selectivity, the texture and surface chemistry of activated carbon should be well designed via the optimization of synthesis conditions. The present work aims to valorize local biomass waste (palm petiole, PP) into highly mesoporous adsorptive activated carbon (ACPP) for the removal of the organic matter (OM) from crude industrial phosphoric acid (26% P2O5). The microwave-assisted synthesis of ACPP was optimized using full factorial design (FFD) and analysis of variance (ANOVA). Experimental factors that govern the removal of OM from phosphoric acid using ACPP were investigated to maximize the purification rate. Even though the yield of OM in phosphoric acid is high, ACPP removes about 81.5% of OM. Several parameters were studied to optimize and understand the adsorption behavior of OM on the surface of ACPP. The adsorption process undergoes pseudo-second-order kinetic, and the adsorption isotherm follows the Sips model. Overall, this research shows that the carbonization of biomass assisted by microwave and the use of H3PO4 as activation agent produces a highly adsorptive activated carbon with high affinity towards removing OM from crude phosphoric acid. Optimizing biomass waste carbonization factors by facile and sustainable routes would benefit industries to produce pure phosphoric acid at a low cost and eco-friendly route.

Development of areca husk resin for purification of crude Millettia pinnata fatty acid methyl ester (biodiesel) and its comparative studies

Development of areca husk resin for purification of crude Millettia pinnata fatty acid methyl ester (biodiesel) and its comparative studies

Digestibility of energy and concentrations of metabolizable energy and net energy varies among sources of bakery meal when fed to growing pigs.

The null hypothesis that there are no differences in concentrations of digestible energy (DE), metabolizable energy (ME), and net energy (NE) among different sources of bakery meal was tested in a regional experiment involving 5 of the universities on the North Central Coordinating Committee-42 on Swine Nutrition. Eleven sources of bakery meal were procured from the swine producing areas in the United States and included in one diet as the only energy containing ingredient, and each diet was then divided into 5 batches that were used at the University of Illinois, Purdue University, University of Kentucky, University of Nebraska, and North Carolina State University. At each university, diets were fed to 22 growing pigs (2 pigs per diet) that were placed in metabolism crates, and feces and urine were collected for 5 d after a 7-d adaptation period. Diets and collected samples of feces and urine were dried and analyzed for gross energy. The apparent total tract digestibility of dry matter (DM) and gross energy and concentrations of DE, ME, and NE were calculated. Results indicated that there were considerable variation in the nutritional composition among the different sources of bakery meal with relatively large coefficients of variation for crude protein, starch, and acid hydrolyzed ether extract, but it was possible to analyze all sources of bakery meal to account for 100% of the ingredients. The average DE, ME, and NE in the 11 sources of bakery meal was 3,827, 3,678, and 2,799 kcal/kg DM, respectively. However, in contrast to the hypothesis, differences (P < 0.05) among sources of bakery meal in concentrations of DE (3,827 ± 201 kcal/kg DM), ME 3,678 ± 200 kcal/kg DM), and NE (2,799 ± 156 kcal/kg DM) were observed, but the variation among the 11 sources of bakery meal was not greater than what is usually observed among different sources of other ingredients. The differences observed are likely a consequence of the different product streams and production procedures used to produce the bakery meal. In conclusion, the average DE, ME, and NE in 11 sources of bakery meal is close to values previously reported, but there is some variation among sources depending on origin.

Prolonged drought regulates the silage quality of maize (Zea mays L.): Alterations in fermentation microecology.

Prolonged drought stress caused by global warming poses a tremendous challenge to silage production of maize. Drought during maize growth and development resulted in altered micro-environment for silage fermentation. How fermentation of silage maize responds to moisture scales remains uncharted territory. In this research, Maize water control trials were conducted and the silage quality and microbial community of drought-affected maize were determined. The results showed that drought stress significantly reduced the dry matter but increased root-to-shoot ratio, soluble sugar and malonaldehyde content in maize. Before fermentation, the crude protein, crude ash and acid detergent fiber contents were significantly increased but the ether extract content was decreased under drought. The crude protein and acid detergent fiber were significantly decreased in the drought affected group after fermentation. Furthermore, water stress at maize maturity stage greatly reduced the number of total bacteria in silage fermentation but increased the proportion of the lactobacillus and lactic acid content of silage. Drought stress alters the microbial ecosystem of the fermentation process and reconstitutes the diversity of the bacterial community and its metabolites. This study provides a theoretical basis for the study of changes in silage fermentation as affected by abiotic stresses.