不同品种鸡蛋中脂肪酸的组成和含量最初没有显着差异,但是在补充亚麻籽油之后,观察到矮化层在蛋中沉积更多的n-3多不饱和脂肪酸(PUFA)。目前,关于不同品种之间卵成分差异的机制研究有限。因此,在这项研究中,每个品种有150只24周的母鸡,包括矮人层和白色来角,饲喂基础饮食或补充2.5%亚麻籽油的饮食。28d后,收集鸡蛋和肝脏样本以确定脂肪酸组成,和血清,肝脏,肠,收集卵泡用于随后的生化,肠道形态学,和脂质代谢相关基因表达分析。收集十二指肠内容物用于微生物分析。结果表明,2个品种肝脏中总n-3PUFA的含量和沉积效率无显著差异,但饲喂亚麻籽油后,矮人蛋中总n-3PUFA的含量和沉积效率明显高于白来亨。亚麻籽油和品种对胆固醇(CHO)没有显着影响,游离脂肪酸(NEFA),低密度脂蛋白(LDL),和雌激素(E2)水平。用亚麻籽油喂养后,两个品种的绒毛高度和绒毛与隐窝之比都增加,十二指肠隐窝深度减少。绒毛与隐窝的比率(4.78vs.3.60)在饲喂亚麻籽油后,矮人层的十二指肠中的含量明显高于白来角。亚麻籽油可以影响十二指肠中的肠道微生物群,并减少与脂肪酸分解相关的微生物群,比如Romboutsia,膜下,叶枯病菌,和梭菌。这可能意味着较少的ALA可以被分解,而更多的ALA可以被吸收到体内。此外,饲喂亚麻籽油后,延伸酶5(ELOVL5)的mRNA水平,脂肪酸去饱和酶1(FADS1),和脂肪酸转运蛋白1(FATP1)在矮人肝脏中的表达明显高于白来格霍恩,而过氧化物酶体增殖物激活受体α(PPAR)的mRNA水平,肉碱棕榈酰转移酶1(CPT1),酰基辅酶A氧化酶1(ACOX1),酰基辅酶A合成酶(ACSL)明显低于WhiteLeghorn。FABP1在矮人十二指肠中的mRNA水平明显高于白来角,而FATP1的mRNA水平明显低于WhiteLeghorn。矮化层肝脏中ELOVL5的蛋白质水平和卵泡中的极低密度脂蛋白受体(VLDLR)显着高于WhiteLeghorn。总之,饲喂亚麻籽油后,矮化层中绒毛高度与隐窝深度的比率较高,可以使更多的α-亚麻酸(ALA)被吸收到体内。矮化层肝脏中FADS1、ELOVL5和FATP1的较高mRNA表达以及ELOVL5的较高蛋白表达增强了ALA向DHA的转化。矮化层卵泡中VLDLR的较高蛋白质表达允许更多的n-3PUFA沉积在卵泡中。这些综合因素有助于矮化层在鸡蛋中沉积更高水平的n-3PUFA的能力,以及提高n-3PUFA的沉积效率。
There was no significant difference in the composition and content of fatty acids in eggs among different breeds initially, but following the supplementation of flaxseed oil, Dwarf Layer were observed to deposit more n-3 polyunsaturated fatty acid (PUFA) in eggs. Currently, there is limited research on the mechanisms underlying the differences in egg composition among different breeds. Therefore, in this study, 150 twenty-four-wk-old hens of each breed, including the Dwarf Layer and White Leghorn, were fed either a basal diet or a diet supplemented with 2.5% flaxseed oil. After 28 d, eggs and liver samples were collected to determine fatty acid composition, and serum, liver, intestine, and follicles were collected for subsequent biochemical, intestinal morphology, and lipid metabolism-related genes expression analysis. Duodenal contents were collected for microbial analysis. The results showed that there was no significant difference in the content and deposition efficiency of total n-3 PUFA in the liver of the 2 breeds, but the content and deposition efficiency of total n-3 PUFA in the egg of Dwarf Layer were significantly higher than those of White Leghorn after feeding flaxseed oil. Flaxseed oil and breeds did not have significant effects on cholesterol (CHO), free fatty acids (NEFA), low-density lipoprotein (LDL), and estrogen (E2) levels. After feeding with flaxseed oil, the villus height and the villus-to-crypt ratio in both breeds were increased and duodenal crypt depth was decreased. The villus-to-crypt ratio (4.78 vs. 3.60) in the duodenum of Dwarf Layer was significantly higher than that in White Leghorn after feeding with flaxseed oil. Flaxseed oil can impact the gut microbiota in the duodenum and reduce the microbiota associated with fatty acid breakdown, such as Romboutsia, Subdolibranulum, Lachnochlostridium, and Clostridium. This may mean that less ALA can be decomposed and more ALA can be absorbed into the body. Additionally, after feeding flaxseed oil, the mRNA levels of elongation enzymes 5 (ELOVL5), fatty acid desaturase 1 (FADS1), and fatty acid transporter 1 (FATP1) in the liver of Dwarf Layer were significantly higher than those in White Leghorn, while the mRNA levels of peroxisome proliferator-activated receptor alpha (PPAR), carnitine palmitoyl transferase 1 (CPT1), Acyl CoA oxidase 1 (ACOX1), and Acyl-CoA synthetase (ACSL) were significantly lower than those in White Leghorn. The mRNA level of FABP1 in the duodenum of Dwarf Layer was significantly higher than that of White Leghorn, while the mRNA level of FATP1 was significantly lower than that of White Leghorn. The protein levels of ELOVL5 in the liver of Dwarf Layer and very low-density lipoprotein receptor (VLDLR) in the follicles were significantly higher than those of White Leghorn. In summary, after feeding flaxseed oil, the higher ratio of villus height to crypt depth in Dwarf Layer allows more α-linolenic acid (ALA) to be absorbed into the body. The higher mRNA expression of FADS1, ELOVL5, and FATP1, as well as the higher protein expression of ELOVL5 in the liver of Dwarf Layer enhance the conversion of ALA into DHA. The higher protein expression of VLDLR in follicles of Dwarf Layer allows more n-3 PUFA to deposit in the follicles. These combined factors contribute to the Dwarf Layer\'s ability to deposit higher levels of n-3 PUFA in eggs, as well as improving the deposition efficiency of n-3 PUFA.