The relationship between lysozyme gene polymorphism and quality changes during the storage of eggs derived from 2 commercial strains of Japanese quail

During the storage irreversible changes occur in eggs that result in a deterioration of their quality. The most significant changes affect the albumen. One of the major proteins of albumen present in egg white is lysozyme, which protects the embryo from microorganisms. This enzyme also contributes to the qualitative characteristics of albumen. It is possible that its polymorphism also affects the quality and stability of the obtained raw material that is, table eggs. Therefore, the aim of this study was to assess the potential effect of polymorphism in the lysozyme gene and protein on the quality changes during the storage of eggs derived from 2 genetic strains of Japanese quail belonging to various utility types. Eggs from selected females of laying and meat-type breeds were stored for 14 wk. During this period the egg quality traits were evaluated 10 times. DNA was isolated from each female and all exons of the lysozyme gene had been sequenced. In total, fourteen SNPs' and one 4-bp indel mutation were identified in exons and adjacent intronic sequences, among which SNP1 (1:32140723) resulted in a substitution of lysine with glutamine (Q21K). The results showed that SNP1 (strain S22), as well as the SNP2, SNP5, SNP7, SNP8, SNP10, SNP11, SNP12 and SNP13 were significantly associated with breaking strength during egg storage in both investigated Japanese quail strains. Furthermore, a 3 haplotype blocks containing nine SNPs (2, 5, 6, 7, 8, 10, 11, 12 and 13) were identified. These blocks displayed 8 distinct haplotypes that had significant association with breaking strength at all storage time points where egg quality analyses were performed. The study also revealed significant effects of breed and storage time on the egg quality traits. These results provide new insights into the genetic basis of egg quality during storage and could be incorporated into the breeding programs involving these strains.

Antimicrobial Cyclic Dipeptides from Japanese Quail (Coturnix japonica) Eggs Supplemented with Probiotic Lactobacillus plantarum

Fifteen cyclic dipeptides (CDPs) containing proline, one cyclo(Phe-Ala) without proline, and a non-peptidyl DL-3-phenyllactic acid were previously identified in the culture filtrates of Lactobacillus plantarum LBP-K10, an isolate from kimchi. In this study, we used Japanese quail (Coturnix japonica) eggs to examine the effects of probiotic supplementation on the antimicrobial CDPs extracted from quail eggs (QE). Eggshell-free QE were obtained from two distinct groups of quails. The first group (K10N) comprised eggs from unsupplemented quails. The second group (K10S) comprised eggs from quails supplemented with Lb. plantarum LBP-K10. The QE samples were extracted using methylene chloride through a liquid-liquid extraction process. The resulting extract was fractionated into 16 parts using semi-preparative high-performance liquid chromatography. Two fractions, Q6 and Q9, were isolated from K10S and identified as cis-cyclo(L-Ser-L-Pro) and cis-cyclo(L-Leu-L-Pro). The Q9 fraction, containing cis-cyclo(L-Leu-L-Pro), has shown significant inhibitory properties against the proliferation of highly pathogenic multidrug-resistant bacteria, as well as human-specific and phytopathogenic fungi. Some of the ten combinations between the remaining fourteen unidentified fractions and two fractions, Q6 and Q9, containing cis-cyclo(L-Ser-L-Pro) and cis-cyclo(L-Leu-L-Pro) respectively, demonstrated a significant increase in activity against multidrug-resistant bacteria only when combined with Q9. The activity was 7.17 times higher compared to a single cis-cyclo(L-Leu-L-Pro). This study presents new findings on the efficacy of proline-containing CDPs in avian eggs. These CDPs provide antimicrobial properties when specific probiotics are supplemented.

Effect of Hen Genotype and Laying Time on Egg Quality and Albumen Lysozyme Content and Activity

According to research, egg quality and lysozyme content are influenced by a number of factors, which are mostly known in the case of commercial hybrids, while in breeds included in genetic resources conservation programmes, new research results in this regard are emerging. The aim of the study was to determine the effect of egg laying time and genotype of selected Polish native breeds of hens on egg quality and lysozyme content and activity in the albumen. The study material consisted of eggs collected from four strains of laying hens included in the Polish conservation programme, i.e., Green-legged Partridge (Z-11), Yellow-legged Partridge (Ż-33), Rhode Island Red (R-11) and Leghorn (H-22). At week 56, 28 eggs were randomly collected at 7:00 and 13:00 h from each breed of hen and assessed for quality. Laying time influenced certain egg quality traits. Eggs laid by hens in the morning were characterised by 1.7 g lower total weight and albumen weight, 2.4 pores/cm² higher number of shell pores, 0.15 higher albumen pH values and 0.17 lower yolk pH values compared to those laid in the morning. The time of laying did not affect the level and activity of lysozyme in the albumen. A significant negative correlation was found between eggshell traits and albumen height, and between Haugh unit and lysozyme content and activity in the albumen. The studied egg quality traits were more influenced by genotype than by the egg-laying time.

Applications of Lysozyme, an Innate Immune Defense Factor, as an Alternative Antibiotic

Lysozyme is a ~14 kDa protein present in many mucosal secretions (tears, saliva, and mucus) and tissues of animals and plants, and plays an important role in the innate immunity, providing protection against bacteria, viruses, and fungi. Three main different types of lysozymes are known: the c-type (chicken or conventional type), the g-type (goose type), and the i-type (invertebrate type). It has long been the subject of several applications due to its antimicrobial properties. The problem of antibiotic resistance has stimulated the search for new molecules or new applications of known compounds. The use of lysozyme as an alternative antibiotic is the subject of this review, which covers the results published over the past two decades. This review is focused on the applications of lysozyme in medicine, (the treatment of infectious diseases, wound healing, and anti-biofilm), veterinary, feed, food preservation, and crop protection. It is available from a wide range of sources, in addition to the well-known chicken egg white, and its synergism with other compounds, endowed with antimicrobial activity, are also summarized. An overview of the modified lysozyme applications is provided in the form of tables.

Effect of Laying Hen Genotype, Age and Some Interior Egg Quality Traits on Lysozyme Content

The objective of the study was to evaluate the quality of eggs laid by native breed hens of different ages (33 and 53 weeks of age), with particular consideration of the lysozyme parameters. Eggs were collected from 6 breeds/strains of laying hens under the genetic resources conservation in Poland, i.e. Greenleg Partridge (Z-11), Yellowleg Partridge (Ż-33), Rhode Island Red (R-11), Rhode Island White (A-33), Sussex (S-66) and Leghorn (H-22). The yolks of eggs from older hens had a more favourable, intense colour, but the freshness parameters (albumen height and Haugh units) of these eggs were lower. The albumen of eggs from older hens showed greater content and higher enzymatic activity of lysozyme in both thin and thick albumen. Among the six strains of hens, lysozyme content and enzymatic activity were highest in the egg albumen of strains Ż-33, Z-11 and R-11, and lowest in that of strain H-22. The analysed eggs showed statistically significant correlations between some interior egg quality traits (albumen weight, albumen height, Haugh units, yolk colour) and the discussed enzyme parameters. These traits are influenced by genotype and age of the hens.

Effect of genotype and some shell quality traits on lysozyme content and activity in the albumen of eggs from hens under the biodiversity conservation program

The aim of the study was to determine shell quality of eggs laid by some strains of native breed hens of different ages, with special consideration of their effect on lysozyme concentration and enzymatic activity. Evaluation was made of the eggshells from 6 breeds/strains of laying hens covered by the gene pool protection program in Poland: Greenleg Partridge (Z-11), Yellowleg Partridge (Ż-33), Rhode Island Red (R-11), Rhode Island White (A-33), Sussex (S-66), and Leghorn (H-22). Significant (P ≤ 0.01) differences were established for all the shell quality characteristics between hen strains. As the birds aged, shell weight and porosity increased, and shell compression strength decreased in all the experimental groups. Lysozyme content was lowest in white-shelled eggs (H-22) and highest in cream-colored and light brown eggs (Z-11, Ż-33, and R-11). Furthermore, age of hens had a greater effect on lysozyme concentration and activity in the eggs than on shell quality traits. Regardless of the layer genotype, eggs from older hens showed higher lysozyme concentration and enzymatic activity.

Apparent metabolisable energy and amino acid digestibility of microalgae Spirulina platensis as an ingredient in broiler chicken diets

1. This work investigates the apparent metabolisable energy (AME), its nitrogen-corrected form (AMEn) and amino acid (AA) digestibility coefficients of the microalgae Spirulina platensis as an ingredient in broiler chicken diets. 2. One group of birds was fed with a basal control diet (BD), and another was fed with a test diet composed of the BD with the addition of the microalgae at a proportion of 200 g/kg. AME and AMEn were assessed by total excreta collection and indigestibility analysis using acid-insoluble ash (AIA) as a marker. 3. The microalgae comprised 888.0 g/kg dry matter (DM), 18.42 MJ/kg gross energy, 514.7 g/kg crude protein, 9.9 g/kg ether extract, 10.6 g/kg crude fibre, 94.4 g/kg ash, 3.1 g/kg Ca and 11.0 g/kg P. 4. The values obtained for AME (13.48 MJ/kg DM) and AMEn (11.72 MJ/kg DM) were higher (p < 0.01) than those obtained using the AIA method (9.39-8.29 MJ/kg DM). The microalgae ileal digestibility coefficients were 0.80 ± 0.04 and 0.78 ± 0.04 for essential and non-essential AA, respectively. 5. Overall, the metabolisable energy content and digestibility of AA for S. platensis indicated that the microalgae are potentially an alternative nutrient source for broilers. The AIA method underestimated AME and AMEn in comparison to the total excreta collection method.

Chicken Ovotransferrin Variants OTFB and OTFC Harboring Substitution of GAT (Asp) to AAT (Asn) in the Codon 500 and their Antimicrobial Activity

Chicken egg white ovotransferrin (OTF) has been reported to exist in three electrophoretic variants (OTF^A, OTF^B and OTF^C). In this report, we identified a causal polymorphism between the OTF^B and OTF^C variants in Japanese and Taiwanese native chickens and compared the antibacterial activity between these two variants. The cDNA sequence analyses from Satsumadori oviducts revealed that three non-synonymous SNPs T1809G (Ser52Ala), A2258G (Ile96Val) and G7823A (Asp500Asn) corresponded to the OTF electrophoretic phenotypes. Of the three SNPs, the G7823A mutation perfectly corresponded to the electrophoretic phenotypes OTF^B (G/G, Asp500Asp), OTF^B/C (G/A, Asp500Asn) and OTF^C (A/A, Asn500Asn) in three chicken populations. The variants OTF^B and OTF^C exhibited similar antibacterial potency against Gram-positive and Gram-negative bacteria. This study provides, for the first time, molecular information on polymorphism of OTF^B and OTF^C variants of chicken ovotransferrin and its effect on the antimicrobial activity of the respective variants.

Identification of TENP as the Gene Encoding Chicken Egg White Ovoglobulin G2 and Demonstration of Its High Genetic Variability in Chickens

Ovoglobulin G2 (G2) has long been known as a major protein constituent of chicken egg white. However, little is known about the biochemical properties and biological functions of G2 because the gene encoding G2 has not been identified. Therefore, the identification of the gene encoding G2 and an analysis of its genetic variability is an important step toward the goal of understanding the biological functions of the G2 protein and its utility in poultry production. To identify and characterize the gene encoding G2, we separated G2 from egg white using electrophoresis on a non-denaturing polyacrylamide gel. Two polymorphic forms of G2 protein (G2^A and G2^B), with different mobilities (fast and slow respectively), were detected by staining. The protein band corresponding to G2^B was electro-eluted from the native gel, re-electrophoresed under denaturing conditions and its N-terminal sequence was determined by Edman degradation following transfer onto a membrane. Sequencing of the 47 kDa G2^B band revealed it to be identical to TENP (transiently expressed in neural precursors), also known as BPI fold-containing family B, member 2 (BPIFB2), a protein with strong homology to a bacterial permeability-increasing protein family (BPI) in mammals. Full-length chicken TENP cDNA sequences were determined for 78 individuals across 29 chicken breeds, lines, and populations, and consequently eleven non-synonymous substitutions were detected in the coding region. Of the eleven non-synonymous substitutions, A329G leading to Arg110Gln was completely associated with the noted differential electrophoretic mobility of G2. Specifically G2^B, with a slower mobility is encoded by A329 (Arg110), whereas G2^A, with a faster mobility, is encoded by G329 (Gln110). The sequence data, derived from the coding region, also revealed that the gene encoding G2 demonstrates significant genetic variability across different chicken breeds/lines/populations. These variants, and how they correlate with egg white properties, may allow us to understand further G2’s functions.

Effects of experimentally increased in ovo lysozyme on egg hatchability, chicks complement activity, and phenotype in a precocial bird

In birds, spectrum of egg white proteins deposited into the egg during its formation are thought to be essential maternal effects. Particularly, egg white lysozyme (LSM), exhibiting great between and within species variability, is considered to be essential for developing avian embryos due to its physiological, antimicrobial, and innate immune defense functions. However, there have been few studies investigating effects of LSM on early post-hatching phenotype, despite its broad physiological and protective role during embryogenesis. Here, we test how experimentally increased concentrations of egg white LSM affect hatchability in Japanese quail (Coturnix japonica) and chick phenotype immediately after hatching (particularly body weight, tarsus length, plasma LSM concentration, and plasma complement activity). Chicks from eggs with increased LSM concentration displayed reduced tarsus length compared to chicks from control eggs while hatchability, body weight and plasma LSM concentration were unaffected. It is worth noting that no effect of increased in ovo lysozyme on eggs hatchability could be related to pathogen-free environment during artificial incubation of experimental eggs causing minimal pressure on embryo viability. While tangible in vivo mechanisms during avian embryogenesis remain to be tested, our study is the first to document experimentally that egg white LSM appears to have growth-regulation role during embryo development, with possible underlying phenotypic consequences in the early post-hatching period in precocial birds.