egg quality
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Parents affect offspring fitness by propagule size and quality, selection of oviposition site, quality of incubation, feeding of dependent young, and their defence against predators and parasites. Despite many case studies on each of these topics, this knowledge has not been rigorously integrated into individual parental care traits for any taxon. Consequently, we lack a comprehensive, quantitative assessment of how parental care modifies offspring phenotypes. This meta-analysis of 283 studies with 1805 correlations between egg size and offspring quality in birds is intended to fill this gap. The large sample size enabled testing of how the magnitude of the relationship between egg size and offspring quality depends on a number of variables. Egg size was positively related to nearly all studied offspring traits across all stages of the offspring life cycle. Not surprisingly, the relationship was strongest at hatching but persisted until the post-fledging stage. Morphological traits were the most closely related to egg size but significant relationships were also found with hatching success, chick survival, and growth rate. Non-significant effect sizes were found for egg fertility, chick immunity, behaviour, and life-history or sexual traits. Effect size did not depend on whether chicks were raised by their natural parents or were cross-fostered to other territories. Effect size did not depend on species-specific traits such as developmental mode, clutch size, and relative size of the egg, but was larger if tested in captive compared to wild populations and between rather than within broods. In sum, published studies support the view that egg size affects juvenile survival. There are very few studies that tested the relationship between egg size and the fecundity component of offspring fitness, and no studies on offspring survival as adults or on global fitness. More data are also needed for the relationships between egg size and offspring behavioural and physiological traits. It remains to be established whether the relationship between egg size and offspring performance depends on the quality of the offspring environment. Positive effect sizes found in this study are likely to be driven by a causal effect of egg size on offspring quality. However, more studies that control for potential confounding effects of parental post-hatching care, genes, and egg composition are needed to establish firmly this causal link.
- MeSH
- dlouhověkost fyziologie MeSH
- genetická zdatnost MeSH
- ovum cytologie fyziologie MeSH
- ptáci fyziologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- metaanalýza MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
The effect of production type (layer vs. broiler breeder), age (onset and end of laying cycle), and temperature (20 and 28°C) on various aspects of the egg production process and quality was evaluated. Highly significant differences were detected between laying hens and broiler breeders (P ≤ 0.001) in all production parameters. Similarly, age significantly affected rate of lay (P ≤ 0.001; 75.4% for young vs. 62.6% for old), mean sequence length (P ≤ 0.001; 7.7 d for young vs. 2.6 d for old), and time of oviposition (P ≤ 0.001). However, there was no effect of temperature on rate of lay, sequence length, or feed intake. Significant interactions between hen type and age were apparent in rate of lay (P ≤ 0.001), sequence length (P ≤ 0.001), and time of oviposition (P ≤ 0.001). A significant interaction between production type and age (P ≤ 0.015) was evident in egg weight, but egg component proportions were dependent only on hen type. Egg shape index was significantly affected by age (P ≤ 0.004), by temperature (P ≤ 0.028), and an interaction between type and age (P ≤ 0.001). Specific gravity declined with age (P ≤ 0.035) and increasing temperature (P ≤ 0.013).
- MeSH
- kladení vajíček fyziologie MeSH
- kur domácí klasifikace MeSH
- stárnutí fyziologie MeSH
- teplota MeSH
- vejce normy MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Eggshell colour, quality, and biosafety of table eggs are of significant commercial interest. To date, there have been few studies investigating the relationship between eggshell pigmentation and internal egg quality in commercially bred birds. Moreover, the genetic basis and mechanisms behind the effects of extrinsic factors on deposition of antimicrobial compounds in egg white and eggshell pigments are not fully understood. In the present study, we evaluate the effect of chicken breed identity, eggshell pigmentation and the role of extrinsic factors (year and breeder identity) on variability in the concentrations of 2 major egg white antimicrobial proteins (AMPs), lysozyme (LSM), and ovotransferrin (OVOTR), across 23 traditional chicken breeds. We found that chicken breed identity and eggshell pigmentation explained most variability in the concentration of egg white LSM and OVOTR. Year and breeder identity were also significant predictors of egg white LSM and OVOTR variability, and showed selective effects on the deposition of both AMPs in egg white. We also documented a positive correlation between concentration of egg white LSM and eggshell cuticle protoporphyrin in tinted and dark brown eggs, but not in brown, white, and blue eggs. We assume that a combination of both intrinsic genetic and hormonally regulated extrinsic factors is responsible for this relationship and for the variability in egg white AMPs. In this study, we demonstrate the existence of a relationship between eggshell pigmentation and egg white AMPs content in the eggs of traditional chicken breeds that may advertise the egg's antimicrobial potential and biosafety. These findings provide novel insights into the relationship between eggshell pigmentation and egg internal quality and may stimulate the recovery and exploitation of traditional chicken breeds for egg production, where the demands for egg quality and biosafety, in conjunction with animal welfare, are a priority.
- MeSH
- imunomodulace genetika MeSH
- kationické antimikrobiální peptidy genetika metabolismus MeSH
- kur domácí genetika imunologie metabolismus MeSH
- pigmentace MeSH
- ptačí proteiny genetika metabolismus MeSH
- vaječná skořápka chemie MeSH
- vaječné proteiny genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
In practice, goose eggs are increasingly used and, therefore, the rheological properties have to be known for processing. The eggs of geese (Landes Goose, Anser anser f. domestica) were stored for one, 2, 3, 4, 6, and 8 wk at a constant temperature 4°C. First of all, the egg quality parameters were described in terms of egg weight, egg weight loss, egg shape index, yolk height, albumen height, yolk index, albumen index, and Haugh units. In the next step the rheological behavior of liquid egg products (egg yolk, albumen, and whole liquid egg) was studied using a concentric cylinder viscometer. Flow curves of all liquid egg products exhibited non-Newtonian shear thinning behavior. This behavior can be described using the Herschel-Bulkley model and for technical application using the Ostwald-de Waele model. The effect of the storage duration on the rheological behavior is different for the different liquid egg products. With the exception of very low shear rates, the viscosity of the egg yolk as well as of the whole liquid egg decreases with storage time. At lower shear rates there is a tendency toward increased albumen viscosity with storage duration. The storage duration also affects the mechanical properties of the eggshell membrane. This effect has been evaluated in terms of the ultimate tensile strength, fracture strain, and fracture toughness. All these parameters increased with the loading rate, but decreased during the egg storage. These mechanical phenomena should be respected, namely in the design of the egg model for the numerical simulation of the egg behavior under different kinds of the mechanical loading.
- MeSH
- husy * MeSH
- ovum fyziologie MeSH
- reologie MeSH
- skladování potravin * MeSH
- vaječná skořápka fyziologie MeSH
- viskozita MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The objective of the study was to evaluate changes during storage time (0, 7, 14, and 21 D) in the weight, albumen quality and its functional properties, and protein content of eggs from enriched cage and free range at 26 and 51 wk of age. Egg weight was affected by a significant interaction between the housing system and the age of hens. Regarding individual factors, heavier eggs (P < 0.001) were obtained with the enriched cage (61.7 g) environment than with free range (59.6 g) environment at 51 wk (P < 0.001) (63.3 g vs. 58.0 g), and freshly laid eggs were heavier compared to eggs stored for 14 and 21 D (P < 0.001). The significant interaction of evaluated factors affecting egg weight loss included the Haugh unit score and pH. Albumen dry matter content was significantly higher in free-range eggs (14.70% vs. 14.0%), in eggs from younger hens (15.0% vs. 13.7%) and in eggs that were stored 21 D. Free-range eggs contained more lysozyme (P < 0.001), and younger hens produced eggs with higher ovotransferrin (P < 0.05) and ovalbumin content (P < 0.01). The data from the study show that the evaluated factors and their interactions significantly affected the physical parameters of the eggs, whereas albumen functional properties and lysozymes, ovalbumin, and ovotransferrin were negligibly affected.
- MeSH
- bydlení zvířat * MeSH
- časové faktory MeSH
- chov zvířat metody MeSH
- kur domácí fyziologie MeSH
- kvalita jídla * MeSH
- ovum chemie MeSH
- skladování potravin statistika a číselné údaje MeSH
- vejce analýza MeSH
- věkové faktory MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
1. The aim of the study was to investigate the effect of melamine-contaminated feed (100 mg/kg) on the distribution of melamine and cyanuric acid in the tissues of laying hens. The effect of a 5-week melamine administration in feed on the egg quality and blood variables of layers was also investigated. 2. A total of twenty 36-week-old ISA Brown layers were used in the experiment. The layers were equally divided into an experimental melamine group (n = 10) and a control group without melamine (n = 10). At the end of the experiment, samples of liver, kidney, breast and thigh muscles were collected from all hens and analysed for the presence of melamine and cyanuric acid by gas chromatography and tandem mass spectrometry. 3. Layers receiving the melamine-contaminated diet laid eggs with decreased eggshell strength. The decrease in shell strength was found in weeks 3 and 4 compared to the initial state (week 0) and week 1. 4. Hens receiving the melamine-contaminated diet also exhibited a higher total red blood cell count and lower mean corpuscular haemoglobin compared to the control group. However, melamine at 100 mg/kg feed had no effects on the blood variables of layers. 5. Melamine was detected in all analysed tissues of layers fed on the melamine-contaminated diet, with its mean concentrations decreasing in the following order: kidney (7.43 mg/kg) > breast muscle (3.88 mg/kg) > liver (3.11 mg/kg) > thigh muscle (1.91 mg/kg). The kidney and liver of layers fed on the melamine-contaminated diet also exhibited the presence of cyanuric acid. 6. On the basis of our results, it can be concluded that the biotransformation of melamine into cyanuric acid proceeded mainly in the liver, and cyanuric acid was eliminated in urine.
- MeSH
- biotransformace MeSH
- játra metabolismus MeSH
- krmivo pro zvířata * MeSH
- kur domácí růst a vývoj fyziologie MeSH
- plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
- počet erytrocytů MeSH
- testy toxicity MeSH
- triaziny metabolismus toxicita MeSH
- vaječná skořápka účinky léků fyziologie MeSH
- vejce MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The study focused on the effects of traditional (benzoate-sorbate and triphosphates) and alternative (nisin, Laktocid, Defence JB, and Galimax Flavor) food preservatives on the microbiological quality and sensory properties of pasteurized liquid whole eggs (LWE). The LWE samples with the addition of a test preservative and a control were stored at 4°C for 45 D. The selected microbiological parameters, sensory attributes, and color space parameters were determined. The results were statistically analyzed by means of factorial ANOVA, followed by the Tukey post hoc test. The multivariate method of principal component analysis based on the correlation matrix was employed to assess the relationships between pH and sensory characteristics of LWE. Total plate counts at the end of storage differed significantly, being the lowest in samples with benzoate-sorbate (1.69 ± 0.12 log cfu.g-1) and Laktocid (2.12 ± 0.12 log cfu.g-1). The final counts of lactic acid bacteria on day 45 were lower in the samples with benzoate-sorbate, triphosphates, nisin, and Laktocid (maximum 1.01 ± 1.44 log cfu.g-1). The amounts of yeasts at the end of storage did not differ among samples with different preservatives; none were detected in any samples with the exception of Defence JB (1.28 ± 1.90 log cfu.g-1). The lowest final mold count was observed in LWE with Laktocid (0.92 ± 1.29 log cfu.g-1). In conclusion, Laktocid showed great potential as a preservative; it had however a negative impact on pH value and the sensory properties of LWE.
Avian egg white is essential for protecting and nourishing bird embryos during their development. Being produced in the female magnum, variability in hen oviduct gene expression may affect egg white composition in domestic chickens. Since traditional poultry breeds may represent a source of variation, in the present study we describe the egg white proteome (mass spectrometry) and corresponding magnum transcriptome (high-throughput sequencing) for 20 hens from five domestic fowl breeds (large breeds: Araucana, Czech golden pencilled, Minorca; and small breeds: Booted bantam, Rosecomb bantam). In total, we identified 189 egg white proteins and 16391 magnum-expressed genes. The majority of egg white protein content comprised proteins with an antimicrobial function. Despite general similarity, Between-class Principal Component Analysis revealed significant breed-specific variability in protein abundances, differentiating especially small and large breeds. Though we found strong association between magnum mRNA expression and egg white protein abundance across genes, coinertia analysis revealed no transcriptome/proteome costructure at the individual level. Our study is the first to show variation in protein abundances in egg white across chicken breeds with potential effects on egg quality, biosafety, and chick development. The observed interindividual variation probably results from post-transcriptional regulation creating a discrepancy between proteomic and transcriptomic data.
- MeSH
- hospodářská zvířata klasifikace genetika metabolismus MeSH
- kur domácí klasifikace genetika metabolismus MeSH
- proteom chemie genetika metabolismus MeSH
- proteomika MeSH
- stanovení celkové genové exprese MeSH
- vaječné proteiny chemie genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
