Translucent eggs of laying hens: a review.

Eggshell quality is a significant characteristic that influences consumer preferences. Eggshell translucency is a common defect in the appearance of eggshells, which are characterized by gray spots that are visible to the naked eye under natural light. The presence of various defects resulting from eggshell translucency has caused a decrease in consumer willingness to purchase eggs, leading to considerable economic losses in the egg industry. Although the impact of eggshell translucency on food safety, egg quality, and hatchability has been extensively investigated, the classification and causes of eggshell translucency remain unclear and lack a systematic summary. In recent studies, new interpretations of evaluation methods and causes of eggshell translucency have been proposed, along with numerous innovative solutions. Therefore, this paper aims to provide a comprehensive review of the evaluation methods, classification, causes, effects, and influencing factors of eggshell translucency and to summarize the treatments for translucent eggs. We believe that this review will serve as a valuable reference for researchers involved in the study of translucent eggs.

Organic Trace Elements Improve the Eggshell Quality via Eggshell Formation Regulation during the Late Phase of the Laying Cycle.

The quality of eggshells is critical to the egg production industry. The addition of trace elements has been shown to be involved in eggshell formation. Organic trace elements have been found to have higher biological availability than inorganic trace elements. However, the effects of organic trace elements additive doses on eggshell quality during the laying period of commercial laying hens required further investigation. This experiment aims to explore the potential mechanisms of different doses of organic trace elements replacing inorganic elements to remodel the eggshell quality of egg-laying hens during the laying period. A total of 360 healthy hens (Lohmann Pink, 45-week-old) were randomly divided into four treatments, with six replications per treatment and 15 birds per replication. The dietary treatments included a basal diet supplemented with inorganic iron, copper, zinc and manganese at commercial levels (CON), a basal diet supplemented with organic iron, copper, zinc and manganese at 20% commercial levels (LOT), a basal diet supplemented with organic iron, copper, zinc and manganese at 30% commercial levels (MOT), and a basal diet supplemented with organic iron, copper, zinc and manganese at 40% commercial levels (HOT). The trial lasted for 8 weeks. The results of the experiment showed that the replacement of organic trace elements did not significantly affect the production performance of laying hens (p > 0.05). Compared with inorganic trace elements, the MOT and HOT groups improved the structure of the eggshells, enhanced the hardness and thickness of the eggshells, increased the Haugh unit of the eggs, reduced the proportion of the mammillary layer in the eggshell, and increased the proportion of the palisade layer (p < 0.05). In addition, the MOT and HOT groups also increased the enzyme activity related to carbonate transport in the blood, the expression of uterine shell gland-related genes (CA2, OC116, and OCX32), and the calcium and phosphorus content in the eggshells (p < 0.05). We also found that the MOT group effectively reduced element discharge in the feces and enhanced the transportation of iron (p < 0.05). In conclusion, dietary supplementation with 30-40% organic micronutrients were able to improve eggshell quality in aged laying hens by modulating the activity of serum carbonate transport-related enzymes and the expression of eggshell deposition-related genes.

Comparative Impact of Hydroxychloride and Organic Sources of Manganese, Zinc, and Copper in Rearing Diets on Pullet Growth, Tibia Traits, Egg Production, and Eggshell Quality in Lohmann Brown Birds up to 50 Weeks of Age.

(1) Background: This study assessed the efficacy of hydroxychloride sources of zinc (Zn), manganese (Mn), and copper (Cu) compared with organic sources in the rearing diets of Lohmann brown pullets, focusing on pullet performance, tibia quality, egg production, and eggshell quality. (2) Methods: A total of 120 birds (six replications and 10 birds each) received diets with Mn, Zn, and Cu from organic or hydroxychloride sources during the rearing phase. After the onset of lay, birds were fed diets containing oxide/sulfate sources up to 50 weeks of age. (3) Results: no significant differences were observed in growth performance and tibia quality during the rearing phase (p > 0.05). From 18 to 24 weeks of age, no carryover effect on egg production performance was observed. However, from 25-50 weeks, pullets fed hydroxychloride sources showed lower feed intake and egg mass compared to the organic group (p < 0.05), whereas egg production and eggshell quality remained similar between groups (p > 0.05). (4) Conclusions: These findings suggest the potential of hydroxychloride sources in rearing diets without compromising overall growth in the pullet phase and feed efficiency in the laying cycle.

Stimulated Full-Thickness Cutaneous Wound Healing with Bioactive Dressings of Zinc and Cobalt Ion-Doped Bioactive Glass-Coated Eggshell Membranes in a Diabetic Rabbit Model.

Eggshell membrane-based biomedical applications have recently received great attention for their wound-healing properties. However, there are limited studies on diabetic wound healing. In this regard, we devised four types of composite eggshell membrane mats with nanoscale coatings of bioactive glass/Zn/Co-doped bioactive glass (ESM + BAG, ESM + ZnBAG, ESM + CoBAG, and ESM + ZnCoBAG) as wound-dressing materials for chronic nonhealing diabetic wounds. A detailed study of the physicochemical properties of the mats was conducted. In vitro studies demonstrated cytocompatibility and viability of human dermal fibroblasts on all four types of mats. The cells also attached finely on the mats with the help of cellular extensions, as evident from scanning electron microscopy (SEM) and rhodamine-phalloidin and Hoechst 33342 staining of cellular components. Endowed with bioactive properties, these mats influenced all aspects of full-thickness skin wound healing in diabetic animal model studies. All of the mats, especially the ESM + ZnCoBAG mat, showed the earliest wound closure, effective renewal, and restructuring of the extracellular matrix in terms of an accurate and timely accumulation of collagen, elastin, and reticulin fibers. Hydroxyproline and sulfated glycosaminoglycans were significantly (p < 0.01, p < 0.05) higher in ESM-ZnCoBAG-treated wounds in comparison to ESM-BAG-treated wounds, which suggests that these newly developed mats have potential as an affordable diabetic wound care solution in biomedical research.

Identification and Characterization of the miRNA Transcriptome Controlling Green Pigmentation of Chicken Eggshells.

Green eggs are mainly caused by inserting an avian endogenous retrovirus (EVA-HP) fragment into the SLCO1B3 gene. Although the genotypes for this insertion allele are consistent, eggshell color (ESC) may vary after a peak laying period; light-colored eggs are undesired by consumers and farmers and result in financial loss, so it is necessary to resolve this problem. miRNAs are small non-coding RNAs that exert essential functions in animal development and diseases. However, the regulatory miRNAs and detailed molecular mechanisms regulating eggshell greenness remain unclear. In the present study, we determined the genotype of green-eggshell hens through the detection of a homozygous allele insertion in the SLCO1B3 gene. The shell gland epithelium was obtained from green-eggshell hens that produced white and green shell eggs to perform transcriptome sequencing and investigate the important regulatory mechanisms that influence the ESC. Approximately 921 miRNAs were expressed in these two groups, which included 587 known miRNAs and 334 novel miRNAs, among which 44 were differentially expressed. There were 22 miRNAs that were significantly upregulated in the green and white groups, respectively, which targeted hundreds of genes, including KIT, HMOX2, and several solute carrier family genes. A Gene Ontology enrichment analysis of the target genes showed that the differentially expressed miRNA-targeted genes mainly belonged to the functional categories of homophilic cell adhesion, gland development, the Wnt signaling pathway, and epithelial tube morphogenesis. A KEGG enrichment analysis showed that the Hedgehog signaling pathway was significantly transformed in this study. The current study provides an overview of the miRNA expression profiles and the interaction between the miRNAs and their target genes. It provides valuable insights into the molecular mechanisms underlying green eggshell pigmentation, screening more effective hens to produce stable green eggs and obtaining higher economic benefits.

3D Printed Eggshell Microparticle-Laden Thermoplastic Scaffolds for Bone Tissue Engineering.

Three-dimensional (3D) printing, an additive manufacturing technique, is increasingly used in the field of tissue engineering. The ability to create complex structures with high precision makes the 3D printing of this material a preferred method for constructing personalized and functional materials. However, the challenge lies in developing affordable and accessible materials with the desired physiochemical and biological properties. In this study, we used eggshell microparticles (ESPs), an example of bioceramic and unconventional biomaterials, to reinforce thermoplastic poly(ε-caprolactone) (PCL) scaffolds via extrusion-based 3D printing. The goal was to conceive a sustainable, affordable, and unique personalized medicine approach. The scaffolds were fabricated with varying concentrations of eggshells, ranging from 0 to 50% (w/w) in the PCL scaffolds. To assess the physicochemical properties, we employed scanning electron microscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis, differential scanning calorimetry, and X-ray diffraction analysis. Mechanical properties were evaluated through compression testing, and degradation kinetics were studied through accelerated degradation with the remaining mass ranging between 89.4 and 28.3%. In vitro, we evaluated the characteristics of the scaffolds using the MC3T3-E1 preosteoblasts over a 14 day period. In vitro characterization involved the use of the Alamar blue assay, confocal imaging, and real-time quantitative polymerase chain reaction. The results of this study demonstrate the potential of 3D printed biocomposite scaffolds, consisting of thermoplastic PCL reinforced with ESPs, as a promising alternative for bone-graft applications.

Time-Dependent Effect of Eggshell Membrane on Monosodium-Iodoacetate-Induced Osteoarthritis: Early-Stage Inflammation Control and Late-Stage Cartilage Protection.

Osteoarthritis (OA) is a chronic degenerative joint disease that causes chronic pain, swelling, stiffness, disability, and significantly reduces the quality of life. Typically, OA is treated using painkillers and non-steroidal anti-inflammatory drugs (NSAIDs). While current pharmacologic treatments are common, their potential side effects have prompted exploration into functional dietary supplements. Recently, eggshell membrane (ESM) has emerged as a potential functional ingredient for joint and connective tissue disorders due to its clinical efficacy in relieving joint pain and stiffness. Despite promising clinical evidence, the effects of ESM on OA progression and its mechanism of action remain poorly understood. This study evaluated the efficacy of Ovomet®, a powdered natural ESM, against joint pain and disease progression in a monosodium iodoacetate (MIA)-induced rodent model of OA in mice and rats. The results demonstrate that ESM significantly alleviates joint pain and attenuates articular cartilage destruction in both mice and rats that received oral supplementation for 5 days prior to OA induction and for 28 days thereafter. Interestingly, ESM significantly inhibited mRNA expression levels of pro-inflammatory cytokines including tumor necrosis factor alpha (TNF-α), interleukin-1ß (IL-1ß), and interleukin-6 (IL-6), as well as inflammatory mediators, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase in the knee joint cartilage at the early stage of OA, within 7 days after OA induction. However, this effect was not observed in the late stage at 28 days after OA induction. ESM further attenuates the induction of protein expression for cartilage-degrading enzymes like matrix metalloproteinase (MMPs) 3 and 13, and a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS-5), in the late-stage. In addition, MIA-induced reduction of the protein expression levels of cartilage components, cartilage oligomeric matrix protein (COMP), aggrecan (ACAN) and collagen type II α-1 chain (COL2α1), and cartilage extracellular matrix (ECM) synthesis promoting transcriptional factor SRY-Box 9 (SOX-9) were increased via ESM treatment in the cartilage tissue. Our findings suggest that Ovomet®, a natural ESM powder, is a promising dietary functional ingredient that can alleviate pain, inflammatory response, and cartilage degradation associated with the progression of OA.

Photodecoration of tungsten oxide nanoparticles onto eggshell as an ultra-fast adsorbent for removal of MB dye pollutant.

Nowadays, the use of natural wastes and adsorbents along with their modification by simple and new methods based on metal oxides to remove dye pollutants has been the focus of many researchers. In this study, for the first time, simple and low-cost modification of eggshell (EGS) with tungsten oxide (WO3) based on the photochemical modification method as a green, ultra-fast, cost-effective, and biodegradable adsorbent is reported to remove of methylene blue (MB) dye pollutant. The EGS modified by WO3 was investigated by EDX, EDX mapping, XRD, FE-SEM, and UV-Vis Diffuse Reflectance (DRS) analyses. The obtained results show that the modified EGS by WO3 has more than ten times (78.5%) the ability to remove MB dye pollutant within 3 min compared to bare EGS (11%). Various parameters including dye pollutant pH, dye concentration, adsorbent dosage, and reusability of the WO3/EGS adsorbent for removal of MB dye pollutant were investigated and the result show that the adsorbent capacity of WO3/EGS is 1.64 mg g-1. EGS adsorbent The synthesis of WO3/EGS adsorbent with a novel photochemical method as a fast and very cheap adsorbent with excellent efficiency can be a promising alternative adsorbent for various purposes in removing dye pollutants from water environments.

Genome-wide association analysis of eggshell color of an F2 generation population reveals candidate genes in chickens.

Eggshell color is an important visual characteristic that affects consumer preferences for eggs. Eggshell color, which has moderate to high heritability, can be effectively enhanced through molecular marker selection. Various studies have been conducted on eggshell color at specific time points. However, few longitudinal data are available on eggshell color. Therefore, the objective of this study was to investigate eggshell color using the Commission International de L'Eclairage L*a*b* system with multiple measurements at different ages (age at the first egg and at 32, 36, 40, 44, 48, 52, 56, 60, 66, and 72 weeks) within the same individuals from an F2 resource population produced by crossing White Leghorn and Dongxiang Blue chicken. Using an Affymetrix 600 single nucleotide polymorphism (SNP) array, we estimated the genetic parameters of the eggshell color trait, performed genome-wide association studies (GWASs), and screened for the potential candidate genes. The results showed that pink-shelled eggs displayed a significant negative correlation between L* values and both a* and b* values. Genetic heritability based on SNPs showed that the heritability of L*, a*, and b* values ranged from 0.32 to 0.82 for pink-shelled eggs, indicating a moderate to high level of genetic control. The genetic correlations at each time point were mostly above 0.5. The major-effect regions affecting the pink eggshell color were identified in the 10.3-13.0 Mb interval on Gallus gallus chromosome 20, and candidate genes were selected, including SLC35C2, PCIF1, and SLC12A5. Minor effect polygenic regions were identified on chromosomes 1, 6, 9, 12, and 15, revealing 11 candidate genes, including MTMR3 and SLC35E4. Members of the solute carrier family play an important role in influencing eggshell color. Overall, our findings provide valuable insights into the phenotypic and genetic aspects underlying the variation in eggshell color. Using GWAS analysis, we identified multiple quantitative trait loci (QTLs) for pink eggshell color, including a major QTL on chromosome 20. Genetic variants associated with eggshell color may be used in genomic breeding programs.

Comparative Analysis of the Ultrastructure, Bubble Pores, and Composition of Eggshells of Dwarf Layer-White and Guinea Fowl.

The decrease in eggshell quality seriously affects production efficiency. Guinea fowl (GF) eggs possess strong eggshells because of their unique crystal structure, and few systematic studies have compared laying hen and GF eggs. Sixty eggs were collected from both 40-week-old Dwarf Layer-White (DWL-White) laying hens and GF, and the eggshell quality, ultrastructure, bubble pores, and composition were measured. The results showed that the DWL-White eggs had a higher egg weight and a lower eggshell strength, strength per unit weight, thickness, and ratio than the GF eggs (p < 0.01). There were differences in the mammillary layer thickness ratio, the effective layer thickness ratio, the quantity of bubble pores (QBPs), the ratio of the sum of the area of bubble pores to the area of the eggshell in each image (ARBE), and the average area of bubble pores (AABPs) between the DWL-White and GF eggs (p < 0.01). The composition analysis demonstrated that there were differences in the organic matter, inorganic matter, calcium, and phosphorus between the DWL-White and GF eggs (p < 0.01). There were positive associations between the mammillary knob number in the image and the QBPs and ARBE and a negative correlation with the AABPs in the DWL-White eggs (p < 0.01). This study observed distinctions that offer new insights into enhancing eggshell quality.

The effect of avian eggshell membrane structure on microbial penetration: A simulation study.

Avian eggshells exhibit excellent antimicrobial properties. In this study, we conducted simulation experiments to explore the defense mechanisms of eggshell membranes with regards to their physical features. We developed a mathematical model for the movement of microorganisms and estimated their penetration ratio into eggshell membranes based on several factors, including membrane thickness, microbial size, directional drift, and attachment probability to membrane fibers. These results not only suggest that an eggshell membrane with multiple layers and low porosity indicates high antimicrobial performance, but also imply that the fibrous network structure of the membrane might contribute to effective defense. Our simulation results aligned with experimental findings, specifically in measuring the penetration time of Escherichia coli through the eggshell membrane. We briefly discuss the significance and limitations of this pilot study, as well as the potential for these results, to serve as a foundation for the development of antimicrobial materials.

Prevalence and antimicrobial susceptibility of Salmonella enteritidis and Salmonella typhimurium isolated from hen eggs and quail eggs in Karaj, Iran.

BACKGROUND AND AIM: Different Salmonella serotypes are considered one of the most important food pathogens in the world. Poultry meat and eggs are the primary carriers of Salmonella in human populations. This study aimed to estimate the Salmonella enteritidis and Salmonella typhimurium contamination rates of retail hen and quail eggs in Karaj, Iran. Moreover, the antimicrobial resistance patterns of the strains were evaluated, and the efficiency of the standard culture method and multiplex polymerase chain reaction (m-PCR) were compared. MATERIALS AND METHODS: In this descriptive cross-sectional study over 1 year (Jan-Dec 2022), 150 commercial and 150 backyard hen eggs and 300 commercial quail eggs, without cracks and fractures, were collected randomly from best selling groceries in Karaj city. All samples were examined for Salmonella contamination independently by standard culture and m-PCR approaches. A standard disc diffusion method was employed to assess the antimicrobial susceptibility of the strains against 18 antimicrobial agents. RESULTS: Out of 300 examined eggs, 2 S. enteritidis strains were isolated from the shell of backyard hen eggs. The same serotype was also detected in the contents of one of these two eggs. One S. typhimurium was isolated from the shell of a commercial hen egg. Overall, the Salmonella contamination of the shell and contents was 1% and 0.3%, respectively. Salmonella was not isolated from the eggshells or the contents of the quail eggs. There was complete agreement between the results of m-PCR and the standard culture methods. Among the 18 tested antibiotics, the highest resistance was recorded for colistin (100%), followed by nalidixic acid (75%). CONCLUSION: As most Salmonella spp. are associated with human food poisoning, continuous surveillance is required to effectively reduce the risk posed by contaminated poultry eggs. Furthermore, mandatory monitoring of antimicrobial use on Iranian poultry farms is recommended.

Biomimetic dentin remineralization using eggshell derived nanohydroxyapatite with and without carboxymethyl chitosan - An in vitro study.

The objective of this study was to evaluate the synergistic effect of eggshell-derived nanohydroxyapatite (EnHA) and carboxymethyl chitosan (CMC) in remineralizing artificially induced dentinal lesions. EnHA and CMC were synthesized using simple chemical processes and characterized using FTIR, XRD, HRSEM-EDX, TEM, DLS and TGA/DTA analyses. A total of 64 pre-demineralized coronal dentin specimens were randomly subjected to following treatments (n = 16):artificial saliva (AS), EnHA, CMC, and EnHA-CMC, followed by pH cycling for 7 days. HRSEM-EDX, Vickers-indenter, and micro-Raman analyses were used to assess surface-topography, microhardness, and chemical analysis, respectively. All tested materials demonstrated non-cytotoxicity when assessed on hDPSCs using MTT assay. FTIR, XRD and thermal analyses confirmed the characteristics of both EnHA and CMC. EnHA showed irregular rod-shaped nanoparticles (30-70 nm) with the presence of Ca,P,Na, and Mg ions. Dentin treated with EnHA-CMC exhibited complete tubular occlusion and highest microhardness whereas the AS group revealed the least mineral deposits (p < 0.05). No significant differences were observed between EnHA and CMC groups (p > 0.05). In addition, molecular conformation analysis revealed peak intensities in collagen's polypeptide chains in dentin treated with CMC and EnHA-CMC, whereas other groups showed poor collagen stability. The results highlighted that EnHA-CMC aided in rapid and effective biomineralization, suggesting its potential as a therapeutic solution for treating dentin caries.

The Chicken Egg: An Advanced Material for Tissue Engineering.

The chicken egg, an excellent natural source of proteins, has been an overlooked native biomaterial with remarkable physicochemical, structural, and biological properties. Recently, with significant advances in biomedical engineering, particularly in the development of 3D in vitro platforms, chicken egg materials have increasingly been investigated as biomaterials due to their distinct advantages such as their low cost, availability, easy handling, gelling ability, bioactivity, and provision of a developmentally stimulating environment for cells. In addition, the chicken egg and its by-products can improve tissue engraftment and stimulate angiogenesis, making it particularly attractive for wound healing and tissue engineering applications. Evidence suggests that the egg white (EW), egg yolk (EY), and eggshell membrane (ESM) are great biomaterial candidates for tissue engineering, as their protein composition resembles mammalian extracellular matrix proteins, ideal for cellular attachment, cellular differentiation, proliferation, and survivability. Moreover, eggshell (ES) is considered an excellent calcium resource for generating hydroxyapatite (HA), making it a promising biomaterial for bone regeneration. This review will provide researchers with a concise yet comprehensive understanding of the chicken egg structure, composition, and associated bioactive molecules in each component and introduce up-to-date tissue engineering applications of chicken eggs as biomaterials.

Efficient synthesis of rare sugars from galactose in hot compressed water using eggshells as an environmentally friendly catalyst.

Aqueous galactose solutions containing eggshell was heated at 120 °C to produce calcium supplements containing rare sugars. Galactose was isomerized to rare sugars with improving rare sugar yields compared to those without eggshell. Organic acids were also formed as byproducts during the reaction. These acids were neutralized by dissolving eggshells with increasing the calcium ion concentration in the solution. When eggshell components (calcium carbonate, magnesium carbonate, or calcium phosphate) were used for the treatment, rare sugars were also formed. Especially, addition of magnesium carbonate improved rare sugar yield, but byproduct formation became more pronounced. Eggshells used in the treatment were used for repeated treatments. When eggshells were used three times, rare sugar yield changed only slightly but the selectivity of rare sugars improved significantly. By these processes, we obtained an aqueous solution of rare sugars containing calcium ion at 295 mg/L, which has potential as ingredients for dietary supplements.

Harnessing potential of avian eggshell membrane derived collagen hydrolysate for bone tissue regeneration.

BACKGROUND: Natural bone grafts are the highly preferred materials for restoring the lost bone, while being constrained of donor availability and risk of disease transmission. As a result, tissue engineering is emerging as an efficacious and competitive technique for bone repair. Bone tissue engineering (TE) scaffolds to support bone regeneration and devoid of aforesaid limitations are being vastly explored and among these the avian eggshell membrane has drawn attention for TE owing to its low immunogenicity, similarity with the extracellular matrix, and easy availability. METHODOLOGY AND RESULTS: In this study, the development of bone ingrowth support system from avian eggshell membrane derived collagen hydrolysates (Col-h) is reported. The hydrolysate, cross-linked with glutaraldehyde, was developed into hydrogels with poly-(vinyl alcohol) (PVA) by freeze-thawing and further characterized with ATR-FTIR, XRD, FESEM. The biodegradability, swelling, mechanical, anti-microbial, and biocompatibility evaluation were performed further for the suitability in bone regeneration. The presence of amide I, amide III, and -OH functional groups at 1639 cm- 1,1264 cm- 1, and 3308 cm- 1 respectively and broad peak between 16°-21° (2θ) in XRD data reinstated the composition and form. CONCLUSIONS: The maximum ratio of Col-h/PVA that produced well defined hydrogels was 50:50. Though all the hydrogel matrices alluded towards their competitive attributes and applicability towards restorative bone repair, the hydrogel with 40:60 ratios showed better mechanical strength and cell proliferation than its counterparts. The prominent E. coli growth inhibition by the hydrogel matrices was also observed, along with excellent biocompatibility with MG-63 osteoblasts. The findings indicate strongly the promising application of avian eggshell-derived Col-h in supporting bone regeneration.

Eggshell waste bioprocessing for sustainable acid phosphatase production and minimizing environmental hazards.

BACKGROUND: The Environmental Protection Agency has listed eggshell waste as the 15th most significant food industry pollution hazard. Using eggshell waste as a renewable energy source has been a hot topic recently. Therefore, finding a sustainable solution for the recycling and valorization of eggshell waste by investigating its potential to produce acid phosphatase (ACP) and organic acids by the newly-discovered B. sonorensis was the target of the current investigation. RESULTS: Drawing on both molecular and morphological characterizations, the most potent ACP-producing B. sonorensis strain ACP2, was identified as a local bacterial strain obtained from the effluent of the paper and pulp industries. The use of consecutive statistical experimental approaches of Plackett-Burman Design (PBD) and Orthogonal Central Composite Design (OCCD), followed by pH-uncontrolled cultivation conditions in a 7 L bench-top bioreactor, revealed an innovative medium formulation that substantially improved ACP production, reaching 216 U L-1 with an ACP yield coefficient Yp/x of 18.2 and a specific growth rate (µ) of 0.1 h-1. The metals Ag+, Sn+, and Cr+ were the most efficiently released from eggshells during the solubilization process by B. sonorensis. The uncontrolled pH culture condition is the most suitable and favoured setting for improving ACP and organic acids production. Quantitative and qualitative analyses of the produced organic acids were carried out using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Lactic acid, citric acid, and hydroxybenzoic acid isomer were the most common organic acids produced throughout the cultivation process. The findings of TGA, DSC, SEM, EDS, FTIR, and XRD analysis emphasize the significant influence of organic acids and ACP activity on the solubilization of eggshell particles. CONCLUSIONS: This study emphasized robust microbial engineering approaches for the large-scale production of a newly discovered acid phosphatase, accompanied by organic acids production from B. sonorensis. The biovalorization of the eggshell waste and the production of cost-effective ACP and organic acids were integrated into the current study, and this was done through the implementation of a unique and innovative medium formulation design for eggshell waste management, as well as scaling up ACP production on a bench-top scale.

Effects of Phytosterol Ester Supplementation on Egg Characteristics, Eggshell Ultrastructure, Antioxidant Capacity, Liver Function and Hepatic Metabolites of Laying Hens during Peak Laying Period.

The aim of this experiment was to investigate the effects of dietary Phytosterol Ester (PSE) supplementation on egg characteristics, eggshell ultrastructure, antioxidant capacity, liver function, hepatic metabolites, and its mechanism of action in Hy-Line Brown laying hens during peak laying period. A total of 256 healthy Hy-Line Brown laying hens were randomly allocated into four groups. The hens in the control group were fed a basal diet, while those in the experimental groups were fed a basal diet further supplemented with 10, 20, and 40 mg/kg PSE, respectively. It was found that the addition of 20 mg/kg and 40 mg/kg PSE to the diets increased egg weight, but decreased egg breaking strength (p < 0.05). The addition of PSEs to the diets increased albumen height and Haugh unit in all experimental groups (p < 0.05). Electron microscopic observation revealed that the mammillary thickness increased significantly at doses of 20 and 40 mg/kg, but the total thickness decreased, and the effective thickness also thinned (p < 0.05). The mammillary width narrowed in all experimental groups (p < 0.001). Dietary supplementation with 40 mg/kg PSE significantly increased egg yolk Phenylalanine, Leucine, and Isoleucine levels (p < 0.05). In untargeted liver metabolomic analyses, L-Phenylalanine increased significantly in all experimental groups. Leucyl-Lysine, Glutamyl-Leucyl-Arginine, and L-Tryptophan increased significantly at doses of 10 and 20 mg/kg (p < 0.05), and L-Tyrosine increased significantly at doses of 10 and 40 mg/kg (p = 0.033). Aspartyl-Isoleucine also increased significantly at a dose of 10 mg/kg (p = 0.044). The concentration of total protein in the liver was significantly higher at doses of 20 and 40 mg/kg than that of the control group, and the concentrations of total cholesterol and low-density lipoprotein cholesterol were significantly reduced (p < 0.05). The concentration of triglyceride and alkaline phosphatase were significantly reduced in all experimental groups (p < 0.05). Steatosis and hemorrhage in the liver were also improved by observing the H&E-stained sections of the liver. Concerning the antioxidant capacity in the liver, malondialdehyde concentration was significantly reduced (p < 0.05) at a dose of 40 mg/kg. In the ovary, malondialdehyde and nitric oxide concentrations were significantly reduced (p < 0.001). In all the experimental groups, plasma nitric oxide concentration was significantly decreased while superoxide dismutase was significantly increased, and total antioxidant capacity concentration was significantly increased (p < 0.05) in the 10 mg/kg and 40 mg/kg doses. Metabolomics analyses revealed that PSEs play a role in promoting protein synthesis by promoting Aminoacyl-tRNA biosynthesis and amino acid metabolism, among other pathways. This study showed that the dietary addition of PSEs improved egg characteristics, antioxidant capacity, liver function, and symptoms of fatty liver hemorrhagic syndrome in Hy-Line Brown laying hens at peak laying stage. The changes in liver metabolism suggest that the mechanism of action may be related to pathways such as Aminoacyl-tRNA biosynthesis and amino acid metabolism. In conclusion, the present study demonstrated that PSEs are safe and effective dietary additives as an alternative to antibiotics.

Integration of Whole-Genome Resequencing and Transcriptome Sequencing Reveals Candidate Genes in High Glossiness of Eggshell.

Eggshell gloss is an important characteristic for the manifestation of eggshell appearance. However, no study has yet identified potential candidate genes for eggshell gloss between high-gloss (HG) and low-gloss (LG) chickens. The aim of this study was to perform a preliminary investigation into the formation mechanism of eggshell gloss and to identify potential genes. The eggshell gloss of 300-day-old Rhode Island Red hens was measured from three aspects. Uterine tissues of the selected HG and LG (n = 5) hens were collected for RNA-seq. Blood samples were also collected for whole-genome resequencing (WGRS). RNA-seq analysis showed that 150 differentially expressed genes (DEGs) were identified in the uterine tissues of HG and LG hens. These DEGs were mainly enriched in the calcium signaling pathway and the neuroactive ligand-receptor interaction pathway. Importantly, these two pathways were also significantly enriched in the WGRS analysis results. Further joint analysis of WGRS and RNA-seq data revealed that 5-hydroxytryptamine receptor 1F (HTR1F), zinc finger protein 536 (ZNF536), NEDD8 ubiquitin-like modifier (NEDD8), nerve growth factor (NGF) and calmodulin 1 (CALM1) are potential candidate genes for eggshell gloss. In summary, our research provides a reference for the study of eggshell gloss and lays a foundation for improving egg glossiness in layer breeding.

Sustainable and Environmentally Friendly Microwave Synthesis of Nano-Hydroxyapatite from Decarbonized Eggshells.

The sustainable microwave (MW) synthesis of hydroxyapatite (HAp) from decarbonized eggshells was investigated. Decarbonization of eggshells, as a natural source of calcium carbonate (CaCO3), was carried out in the current study at ambient conditions to reduce the footprint of CO2 emissions on our environment where either calcination or acidic direct treatments of eggshells produce CO2 emissions, which is a major cause for global warming. Eggshell decarbonization was carried out via the chemical reaction with sodium hydroxide (NaOH) alkaline solution in order to convert eggshell waste into calcium hydroxide (Ca(OH)2) and simultaneously store CO2 as a sodium carbonate (Na2CO3) by-product which is an essential material in many industrial sectors. The produced Ca(OH)2 was mixed with ammonium dihydrogen phosphate (NH4H2PO4) reagent at pH~11 before being subjected to MW irradiation at 2.45 GHz frequency for 5 min using 800 Watts to prepare HAp. The prepared Nano-HAp was characterized using X-ray diffraction (XRD) where the crystal size was ~28 nm using the Scherrer equation. The elongated rod-like nano-HAp crystals were characterized using scanning electron microscopy (SEM) equipped with dispersive energy X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). MW synthesis of decarbonized eggshells is considered as a sustainable and environmentally friendly route to produce promising bioceramics such as nano-HAp. Concurrently, decarbonization of eggshells offers the ability to store CO2 as a high value-added Na2CO3 material.