A Method to Reduce the Occurrence of Egg Translucency and Its Effect on Bacterial Invasion.

Translucent egg consumption is low due to consumer acceptance and quality concerns, which is a problem that egg producers need to address. This study was performed to evaluate the reasons for the high occurrence of egg translucency in summer, as well as whether the addition of mono-dicalcium phosphate (MDCP) to the diet can relieve eggshell translucency and whether eggshell translucency is associated with the risk of bacterial invasion. A total of 72 laying hens that were 36 weeks old were randomly divided into control (CON) and MDCP groups and fed in the same environment. Results showed that the number of translucent eggs increases in July and August as the temperature and humidity increase. Compared with the CON group, in July, August, and October, the translucent egg grade (TEG) of the MDCP group was lower than that of the CON group (p < 0.05). TEG was correlated with mastoid space height (MSH), width (MSW), and area (MSA) (correlation coefficients 0.63, 0.59, and 0.68, respectively, p ≤ 0.05). There was no significant difference in the invasion rate of E. coli between translucent and non-translucent egg groups (47.2% vs. 39.33%), and translucent area and non-translucent area (13.49% vs. 15.08%). In conclusion, our results show that dietary MDCP may alleviate eggshell translucency and that eggshell translucency would not increase the probability of E. coli cross-shell penetration rate.

Comparative N-Glycoproteomic Investigation of Eggshell Cuticle and Mineralized Layer Proteins.

The eggshell cuticle layer (ECL) and eggshell mineralized layer (EML) contain amounts of glycoproteins and proteoglycans. However, there were few comprehensive reports about the effect of post-translational modifications on protein structure and function which requires investigation. Therefore, we used comparative N-glycoproteomics to study glycoproteins in the ECL and EML. We identified a total of 272 glycoproteins in this experiment and found that glycoproteins located in EML were more than that in ECL. Moreover, they showed distinct functional difference between both layers. As N-glycosylation of ovocleidin-17 and ovocleidin-116 in the EML affected eggshell mineralization, some glycoproteins located in ECL, like ovotransferrin and ovostatin-like, possessed antibacterial activity. The several regulated glycoproteins in the EML may pertain to the regulation of mineralization, while glycosylated proteins in the ECL may contribute to molecular adhesion and defense against microbial invasion. This study provides new insights into the eggshell matrix protein contents of the ECL and EML.

Effects of different duck rearing systems on egg flavor and quality and microbial diversity.

The fishy odor of duck eggs has restricted their consumption and industrial development, a problem that producers need to address. We estimated the effects of cage, floor, and pond rearing systems on duck egg flavor, egg quality, and microbial diversity by evaluating yolk trimethylamine (TMA) content, egg quality, and the differences between duck cecum (cage cecum, CC; floor cecum, FC; pond cecum, PC) and the environment (cage environment, CE; floor environment, FE; pond environment, PE). The results show that the yolk TMA content of the floor-rearing and pond-rearing systems was significantly higher than that of the cage-rearing system (P < 0.001), with no difference between the floor and pond-rearing systems. No significant differences were detected in egg quality among the rearing systems. Firmicutes, Actinobacteria, and Bacteroidetes were the dominant phyla in the cecum, and in the rearing environment, Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria were the dominant phyla. The results of α and ß diversity analyses show that changes in the rearing system affected the composition and diversity of duck cecal microbes. In addition, we screened several genera that may be related to the production of TMA in duck cecum under different rearing systems using LEfSe analysis; for example, Subdoligranulum in the CC group; Romboutsia in the FC group; and Lactobacillus, Clostridium, and Streptococcus in the PC group. In conclusion, the rearing system affects the cecal microbes of ducks, which in turn affect the deposition of TMA in duck eggs but have no adverse effect on egg quality. This study provides a basis for the development of rearing strategies to reduce the fishy odor of egg yolk in the duck industry.

Crustal melting in orogenic belts revealed by eclogite thermal properties.

Partial melting in the continental crust may play a critical role on the behavior of continents during collision. However, the occurrence of partial melt in orogenic continental crust is not well understood. Since the temperature of the orogen is controlled by the thermal properties of constituent rocks, we measured the thermal conductivity and diffusivity of eclogite, the most important ultrahigh pressure metamorphic rocks, as a function of pressure, temperature, composition, and water content, and simulated the thermal structure of the Sulu and Himalaya-Tibet orogens in eastern and southwestern China, respectively. Our results show that the temperature at ~30-km depth beneath the orogens reaches the solidus of wet granite and phengite (~940 K), therefore, the partial melting in the orogenic continental crust is well explained. The melt may facilitate the exhumation of subducted crust, produce the low seismic-velocity zone, and cause the high-conductivity anomaly in the shallow depth of orogenic belts.

Research Note: L*a*b* color space for prediction of eggshell pigment content in differently colored eggs.

Eggshell color is the most intuitive external feature that affects consumer acceptance. Different eggshell colors are mainly determined by protoporphyrin IX and biliverdin content. The selection of eggshell color by the human eye with an eggshell color fan can be roughly classified. Although more technologically advanced, a colorimeter or spectrophotometer might be of limited use when observing a variety of shell colors, such as brown, olive, green, and blue. This study aimed to provide a convenient and accurate method for predicting the content of eggshell pigments by measuring eggshell color using the Commission International de L'Eclairage (CIE) L*a*b* system. The results showed the deepening of eggshell color in brown and blue eggs was correlated with increased eggshell pigment deposition, and eggshell color was significantly positively correlated with eggshell pigment content (P < 0.01). Furthermore, the adjusted R2 of the fitted function was in the range of 0.81 to 0.89, and the Spearman rank correlation coefficient between the predicted and true values was in the range of 0.89 to 0.93. In brief, the L*a*b* method of measuring eggshell color to predict the amount of eggshell pigment deposition is convenient, effective, and promising for layer production.

Associations of the T329S Polymorphism in Flavin-Containing Monooxygenase 3 With Atherosclerosis and Fatty Liver Syndrome in 90-Week-Old Hens.

This study aimed to evaluate the effects of the spontaneous genetic mutation T329S in flavin-containing monooxygenase 3 (FMO3) on atherosclerosis (AS), fatty liver syndrome (FLS), and adiposity in 90-week-old layers. At 90 weeks of age, 27 FMO3 genotyped Rhode Island White chickens (consisting of nine AA hens, nine AT hens, and nine TT hens) with normal laying performance were selected. The AS lesions, incidence of FLS, fat deposition, metabolic characteristics, and production performance of these egg-layers with different FMO3 genotypes were assessed. The T329S mutation in TT hens reduced the AS lesions (P < 0.01) and altered the plasma metabolic indices more than it did in the AA and AT hens. Furthermore, it reduced the incidence of FLS, hepatic triglyceride deposition (P < 0.05), liver indices (P < 0.05), and fat deposition (P < 0.05) in the subcutis and abdomen of TT hens compared to those of AA and AT hens. Moreover, as an effect of T329S, TT hens laid a higher than average number of eggs and maintained a higher egg-laying rate from 68 to 90 weeks than AA and AT hens. Our study confirmed that the T329S mutation in FMO3 could reduce the development of AS lesions, the incidence of FLS, and fat deposition, which are associated with changes in plasma and hepatic metabolic indices and improvements in the laying performance of older layers. Our results may provide a new strategy for using the T329S mutation to improve the health status and production performance of layers during the late laying period.

Antibacterial Properties of TMA against Escherichia coli and Effect of Temperature and Storage Duration on TMA Content, Lysozyme Activity and Content in Eggs.

Studies on trimethylamine (TMA) in egg yolk have focused on how it impacts the flavor of eggs, but there has been little focus on its other functions. We designed an in vitro antibacterial test of TMA according to TMA concentrations that covered the TMA contents typically found in egg yolk. The change in TMA content in yolk was analyzed at different storage temperatures and for different storage durations. The known antibacterial components of eggs, including the cuticle quality of the eggshell and the lysozyme activity and content in egg white, were also assessed. The total bacterial count (TBC) of different parts of eggs were detected. The results showed that the inhibitory effect of TMA on Escherichia coli (E. coli) growth increased with increasing TMA concentration, and the yolk TMA content significantly increased with storage duration (p < 0.05). The cuticle quality and lysozyme content and activity significantly decreased with storage time and increasing temperature, accompanied by a significant increase in the TBC on the eggshell surface and in the egg white (p < 0.05). This work reveals a new role for trace TMA in yolks because it reduces the risk of bacterial colonization, especially when the antibacterial function of eggs is gradually weakened during storage.

Neoproterozoic magmatism in eastern Himalayan terrane.

Geochronological investigation on gneisses of granitic to leucogranitic compositions in Cuona, south Tibet, reveal that their protoliths formed at 808.8±7.9-816.4±3.4Ma and 855.8±7.0Ma, respectively. Zircon rims from the granitic gneiss record a metamorphic age of 739.4±4.3Ma. Lu-Hf isotopic analyses on zircon grains with Neoproterozoic ages yield negative εHf(t) values from -9.0 to -4.2, and the corresponding two-stage Hf model ages are 1965-2228Ma. Whole-rock geochemical data indicate that all granitic gneisses are K-riched calc-alkali series. These new data together with literature data show that (1) the Himalayan terrane experienced an episode of Neoproterozoic magmatism at 850-800Ma; (2) the Neoproterozoic magma of granitic compositions were derived from partial melting of ancient crusts, possibly due to the thermal perturbation related with the breakup of the Rodinia supercontinent.

Evidence for a biogenic, microorganismal origin of rock varnish from the Gangdese Belt of Tibet.

In the present study we examined material from the Ashikule Basin of Tibet. Chemical analyses were performed by use of energy dispersive X-ray spectroscopy and electron probe microanalysis to clarify whether the varnish layers that had developed on the surface of the rhyolite are indeed composed of varnish bodies and silica glaze. Electron microscopic analyses revealed that the surface of the varnish is covered both by filamentous hyphae bacterial and cocci-shaped forms. Within the varnish mineral layer in those samples two forms of bacteria-like microorganisms exist; cocci as tightly packed bacterial aggregates [within varnish bodies], and bacillus-like microorganisms [within the varnish matrix, that surrounds the varnish bodies]. The bacillus-like forms are embedded in a network of filaments that have diameters between 35 and 45 nm. These bacilli with the surrounding filaments are assumed to have been involved in biofilm formation (synthesis of extracellular polymeric substances) prior to their live burial. We concluded that the formation of the varnish layers was for the most part biogenically driven by microorganisms.