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.

The purpose of this study was to compare the differences in the content of functional nutrients in eggs, performance parameters, and egg quality parameters of different chicken breeds. In Trial 1, 150 41-week-old hens of each breed, including the Dwarf Layer, White Leghorn, Silky fowl, Beijing-you chicken, and Shouguang chicken, were randomly assigned to the control (CON) and 2.5% flaxseed oil (FSO) groups to compare the difference in n-3 polyunsaturated fatty acid (PUFA) content in eggs. The contents of α-linolenic acid (ALA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and total n-3 PUFA in eggs were increased (p < 0.05) in the FSO groups. The ALA (4.28%), DHA (2.03%), and total n-3 PUFA (6.46%) contents in eggs of Dwarf Layer were the highest among the five breeds (p < 0.05). To further verify if other functional nutrients also have such differences, 600 24-week-old White Leghorn and Dwarf Layer were allocated to four groups: CON, FSO, 0.02% selenium-enriched yeast (SEY), and 0.20% marigold flower extract (MFE), in Trial 2. The content of functional nutrients in eggs was significantly increased (p < 0.05) after feeding these additions. After feeding FSO, the eggs of the Dwarf Layer had a higher n-3 PUFA content than the White Leghorn (p < 0.05). However, no significant differences were found in selenium and lutein content in different breeds. Performance and egg quality were not negatively impacted by FSO, SEY, or MFE.

我国是世界上最大的蛋品消费国,日常生活中,水煮鸡蛋是常见早餐类型,每天早上吃一个水煮鸡蛋,可以为身体提供多种营养物质.鸡蛋是人体磷脂类、各种维生素、多种矿物质元素、蛋白质和磷酸盐等物质的重要来源,每100 g鸡蛋含蛋白质12.5 g,胆固醇350 mg,维生素B122.30 g,维生素A 0.2 g,钠120 mg,钾130 mg,钙50 mg,能够给身体提供能量.

The purpose of this study is to investigate the characteristics of egg consumption in China and the production of functional eggs, and finally enrich the types of shell egg products. Trial 1 explored the influence of egg quality on Chinese consumers' willingness to purchase eggs through a questionnaire, which investigated 1,317 consumers' preferences for egg appearance, factors influencing egg purchase, and purchase of functional eggs. The results showed that about 65% of respondents ate more than 4 eggs per wk, pink eggs were the most popular in China, about 65% of consumers preferred eggs with an egg weight of 48 to 58 grams. For functional eggs, 75.32% of consumers have never heard of them. Preferences for eggshell color and yolk color varied by geographic region, with darker colors preferred in Northeast China. Based on the survey results of functional eggs consumption in Trial 1, the dwarf layers of China Agricultural University were used in Trial 2 to produce functional eggs. The eggs are small and pink in color, which is in line with the preferences of Chinese consumers. Three hundred dwarf layers were divided into 4 groups, using the linseed oil added, marigold extract added, and yeast selenium added diets to produce normal, n-3 fatty acid-enriched, lutein-enriched and selenium-enriched eggs by feeding for 28 d, determined the eggs' nutrient content and egg quality. The results showed that the n-3 fatty acid, lutein and selenium contents of the eggs of dwarf layers were significantly increased by changing the diets and did not affect the egg weight, eggshell strength, Haugh units or the proportion of egg parts. The results of this study are helpful to understand the trend of egg consumption preferences in China, and on this basis to produce functional eggs that meet the consumers' expectations.

为研究莆田黑鸭产黑色蛋的原因,选取莆田黑鸭黑色蛋、北京鸭蛋、丝羽乌骨鸡蛋与鹌鹑蛋作为试验材料,以4％乙酸分离禽蛋胶护膜层,以离心法取沉淀,收集胶护膜;用粉碎机对提取到的胶护膜进行粉碎,用蛋白酶K降解蛋白,冷冻干燥后用扫描电镜观察不同禽蛋的胶护膜提取物.结果显示:莆田黑鸭黑色鸭蛋胶护膜层中含有大量黑色素,黑色素颗粒形态为杆状,长度为(0.71±0.11)μm,宽度为(0.24±0.04)μm,长宽比约为3:1;北京鸭蛋和丝羽乌骨鸡蛋胶护膜中色素含量较少,无法通过电镜观察到;鹌鹑蛋胶护膜中的主要色素为原卟啉,原卟啉颗粒为不规则的球状结构,大小为(0.63±0.28)μm.研究表明,莆田黑鸭产黑色蛋的形成原因是由于黑色素在蛋壳胶护膜层的沉积所致.研究结果丰富了对家禽蛋壳颜色的认识,鉴定了黑色素形态的多样性,并间接发现了家禽输卵管上皮分泌黑色素的功能,为进一步研究家禽黑色素的合成、分泌和沉积提供了理论参考.