Kawamura Nonoka, Yokoyama Reo, Takaya Masahiro, Ono Ryoko, Goto Tatsuhiko
Department of Life and Food Sciences, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
Engineering Department, Hokuryo Co., Ltd., Kita-Hiroshima, Hokkaido 061-1154, Japan.
J Poult Sci. 2023 Jan 25;60(1):2023007. doi: 10.2141/jpsa.2023007.
In recent years, the market share for cage-free eggs has gradually increased. Because commercially available cage-free eggs are often produced not only by several housing systems but also with different feed crude protein (CP) levels, there are combined effects of feed and housing systems between cage-free and cage eggs. Therefore, using field data, this study aimed to determine the combined effects of feed and housing systems on egg traits and yolk and albumen amino acids in table eggs. Brown layers (n = 40) at the middle laying stage under two feed and housing systems (cage, CP 15.5% diet; barn, CP 17.0% diet) were used. One-way analysis of variance and Pearson's correlation analysis were used to evaluate 10 egg traits, 19 yolk amino acid traits, and 20 albumen amino acid traits. We observed significant effects of feed and housing on two egg traits (yolk weight and eggshell color redness), 16 yolk amino acids (Asp, Glu, Asn, Ser, Gln, His, Arg, Thr, Ala, Tyr, Met, Cys, Ile, Leu, Phe, and Lys), and 14 albumen amino acids (Asp, Asn, Ser, Gln, Gly, His, Arg, Thr, Ala, Val, Met, Cys, Ile, and Leu). This study revealed that eggs from the barn system (CP 17.0%) contained higher levels of free amino acids in 15 yolk and nine albumen amino acid traits. Phenotypic correlations among the 49 egg traits indicated similar correlation patterns in both systems, which implies that the balance of free amino acid content in yolk and albumen is similar in each system. Although some potential confounding factors may be present for comparing egg content between cage (CP 15.5%) and barn (CP 17.0%) systems, this study suggests that commercially available cage-free eggs may be different from cage eggs not only in external egg traits but also yolk and albumen amino acid traits.
近年来，散养鸡蛋的市场份额逐渐增加。由于市售散养鸡蛋通常不仅由多种饲养系统生产，而且饲料粗蛋白（CP）水平也不同，因此散养鸡蛋和笼养鸡蛋在饲料和饲养系统方面存在综合影响。因此，本研究利用实地数据，旨在确定饲料和饲养系统对食用鸡蛋的蛋品质以及蛋黄和蛋清氨基酸的综合影响。选用了处于产蛋中期的褐壳蛋鸡（n = 40），采用两种饲料和饲养系统（笼养，CP 15.5%的日粮；鸡舍饲养，CP 17.0%的日粮）。采用单因素方差分析和Pearson相关分析来评估10个蛋品质性状、19个蛋黄氨基酸性状和20个蛋清氨基酸性状。我们观察到饲料和饲养方式对两个蛋品质性状（蛋黄重量和蛋壳颜色红度）、16种蛋黄氨基酸（天冬氨酸、谷氨酸、天冬酰胺、丝氨酸、谷氨酰胺、组氨酸、精氨酸、苏氨酸、丙氨酸、酪氨酸、甲硫氨酸、半胱氨酸、异亮氨酸、亮氨酸、苯丙氨酸和赖氨酸）和14种蛋清氨基酸（天冬氨酸、天冬酰胺、丝氨酸、谷氨酰胺、甘氨酸、组氨酸、精氨酸、苏氨酸、丙氨酸、缬氨酸、甲硫氨酸、半胱氨酸、异亮氨酸和亮氨酸）有显著影响。本研究表明，鸡舍饲养系统（CP 17.0%）生产的鸡蛋在15种蛋黄氨基酸性状和9种蛋清氨基酸性状中游离氨基酸含量较高。49个蛋品质性状之间的表型相关性表明，两种系统中的相关模式相似，这意味着每个系统中蛋黄和蛋清中游离氨基酸含量的平衡相似。尽管在比较笼养（CP 15.5%）和鸡舍饲养（CP 17.0%）系统的鸡蛋成分时可能存在一些潜在的混杂因素，但本研究表明，市售散养鸡蛋可能不仅在外部蛋品质性状上，而且在蛋黄和蛋清氨基酸性状上都与笼养鸡蛋不同。
