Li Peng, Zhao Yizhu, Yan Shaojia, Song Bocheng, Liu Yongfa, Gao Mingkun, Tang Dazhi, Guo Yuming
State Key Laboratory of Animal Nutrition, China Agricultural University, Beijing, 100193, China.
J Anim Sci Biotechnol. 2022 Jan 5;12(1):126. doi: 10.1186/s40104-021-00647-2.
Soya saponin (SS), an active compound in soybean meals, has been widely studied in the medical field. However, it was considered as an anti-nutritional factor in poultry diets. The objective of this experiment was to measure the effects of dietary SS using three dietary treatments on egg-laying performance and immune function of laying hens. Birds were fed a low soybean meal basal diet (CON), a low-SS diet (50 SS) containing 50 mg/kg SS, or a high-SS diet (500 SS) containing 500 mg/kg SS for 10 weeks. At the end of the 5th and 10th week of the trial, samples were collected for analysis.
Results showed that with 50 mg/kg SS supplementation, the egg production rate, feed conversion ratio (FCR), and eggshell quality tended to be improved. Serum follicle stimulating hormone (FSH) and Interleukin-4 (IL-4) levels were also elevated as well as the peripheral blood LPS stimulation index, the proportion of B lymphocytes, and antibody titer of bovine serum albumin (BSA). We also found that mRNA levels of follicle stimulating hormone receptor (FSHR) in ovarian, nuclear transcription factor kappa B (NF-κB), Transforming growth factor (TGF-β) and interferon γ (IFN-γ) in spleen were up-regulated at the end of the trial. Additionally, dietary 50 mg/kg SS improved the ileal flora via up-regulating the relative abundance of Lactobacillus, Romboutsia and Lactobacillus delbrueckii. Although the immune related indicators were improved with 500 mg/kg SS supplemented, it seemed to have a negative influence on the laying-performance. Specifically, serum alanine aminotransferase (ALT), alkaline phosphatase (ALP), and the ratio of IFN-γ to IL-4 were increased in the 500 SS group at the end of the trial. The mRNA levels of gonadotropin releasing hormone 1 (GnRH1) in Hypothalamus, the estrogen related receptor (ERR) in ovaries were downregulated as well as the egg production rate during the trial with 500 mg/kg SS supplemented.
The egg production performance was improved by dietary supplemented with 50 mg/kg SS via increasing ovarian FSHR transcription level and serum estrogen level. A beneficial shift in intestinal microflora was recorded, and the immune function of laying hens was also improved with 50 mg/kg SS supplementation. Surprisingly, the long-term supplementation of 500 mg/kg SS exerted a negative impact on the laying performance and physiological functions of the liver of laying hens.
大豆皂苷（SS）是豆粕中的一种活性化合物，在医学领域已得到广泛研究。然而，它在禽类日粮中被视为一种抗营养因子。本试验的目的是通过三种日粮处理来测定日粮中SS对蛋鸡产蛋性能和免疫功能的影响。给鸡饲喂低豆粕基础日粮（CON）、含50mg/kg SS的低SS日粮（50 SS）或含500mg/kg SS的高SS日粮（500 SS），持续10周。在试验的第5周和第10周结束时，采集样本进行分析。
结果表明，添加50mg/kg SS可使产蛋率、饲料转化率（FCR）和蛋壳质量有提高的趋势。血清促卵泡激素（FSH）和白细胞介素-4（IL-4）水平以及外周血LPS刺激指数、B淋巴细胞比例和牛血清白蛋白（BSA）抗体效价也有所升高。我们还发现，试验结束时，卵巢中促卵泡激素受体（FSHR）的mRNA水平、脾脏中核转录因子κB（NF-κB）、转化生长因子（TGF-β）和干扰素γ（IFN-γ）的mRNA水平上调。此外，日粮添加50mg/kg SS通过上调乳酸杆菌、罗姆布茨菌和德氏乳杆菌的相对丰度改善了回肠菌群。虽然添加500mg/kg SS可改善免疫相关指标，但似乎对产蛋性能有负面影响。具体而言，试验结束时，500 SS组血清丙氨酸氨基转移酶（ALT）、碱性磷酸酶（ALP）以及IFN-γ与IL-4的比值升高。在添加500mg/kg SS的试验期间，下丘脑促性腺激素释放激素1（GnRH1）、卵巢中雌激素相关受体（ERR）的mRNA水平下调，产蛋率也下降。
日粮添加50mg/kg SS可通过提高卵巢FSHR转录水平和血清雌激素水平来改善产蛋性能。记录到肠道微生物群发生有益变化，添加50mg/kg SS也可改善蛋鸡的免疫功能。令人惊讶的是，长期添加500mg/kg SS对蛋鸡的产蛋性能和肝脏生理功能产生负面影响。
