饲粮中过量镁对新杨黑羽蛋鸡鸡蛋暗斑和蛋壳微生物组成的影响

为研究饲粮中镁对新杨黑羽蛋鸡鸡蛋暗斑形成和蛋壳微生物组成的影响，选取35周龄、所产鸡蛋易发暗斑的新杨黑羽蛋鸡48只，随机分成3组，每组16只(单笼饲养)，分别饲喂镁浓度为843.55(A)、2 009.80(B)和3 206.05 (C) mg·kg^-1的试验饲粮，为期5周，检测鸡蛋暗斑、鸡蛋品质、蛋壳微生物的差异。结果表明，与B和C处理相比，A处理鸡蛋的暗斑等级极显著降低(P<0.01)，蛋白高度和哈氏单位均显著提高(P<0.05)。通过16S rDNA测序，在蛋壳表面共检测到969个OTUs，其中，A、B、C处理分别检测到670、787、848个OTUs；随着储存时间的延长，微生物OTU类别数增加；1级暗斑等级的OTU类别数极显著低于暗斑等级较高的鸡蛋(P<0.01)。综上述所，饲粮中较低的镁浓度会减少鸡蛋暗斑，提高蛋白高度和哈氏单位。

Effects of Excess Dietary Magnesium on Translucent Egg and Eggshell Microorganism of Xinyang Black Feather

To investigate the effects of excessive dietary magnesium on the formation of translucent egg and eggshell microorganism composition of Xinyang black feather laying hens， 48 Xinyang black feather laying hens of 35-week-old whose eggs were prone to egg spotting， were randomly divided into three groups with 16 hens per group （one hen in one cage）. Hens were fed with experimental diets of 843.55 （A）， 2 009.80 （B） and 3 206.05 mg·kg^-1 （C）， respectively. The experiment lasted for 5 weeks. Translucent egg， egg quality and eggshell microorganism were detected. The results showed， compared with B and C treatments， the translucent egg grade of eggs in A treatment significantly decreased （P<0.01）， and the albumen height and Haugh unit significantly increased （P<0.05）. A total of 969 OTUs （operational taxonomic units） were detected by 16s rDNA sequencing， which were 670， 787 and 848 OTUs in A， B and C treatments， respectively. The OTUs increased with the increase of storage time. The OTU number of translucent egg grade 1 was significantly lower than those of other eggs with higher translucent egg grade （P<0.01）. The diets of lower magnesium concentration would reduce translucent egg rate and increase albumen height and Haugh unit.