Department of Animal Sciences, College of Agriculture, Isfahan University of Technology, Isfahan, Iran.
J Anim Physiol Anim Nutr (Berl). 2022 Jul;106(4):860-871. doi: 10.1111/jpn.13586. Epub 2021 Jun 22.
This study assessed the effects of different levels of milk thistle (Silybum marianum) meal (MTM) on egg quality traits, oxidative stability, blood biochemical parameters and liver health indices in laying hens receiving diets supplemented with lipid from different sources. For this purpose, Leghorn laying hens (Hy-Line W-36) were randomly assigned to 12 experimental treatments with eight replicates of five birds each. Dietary treatments consisted of four dietary fat sources (fish oil, sunflower oil, poultry oil and fat powder, each with different fatty acid profiles) and three levels of MTM (0.0, 15 and 30 g/kg) offered through 10 days of adaptation and 70 days of main recording. Results showed that dietary inclusion of polyunsaturated fatty acids, including fish or sunflower oils, reduced serum cholesterol content but increased blood malondialdehyde (MDA) concentration (p < 0.05). While fish oil improved the yolk colour index and Haugh unit (p < 0.05), it decreased yolk cholesterol concentration (p < 0.01). The highest hepatic glycogen content and tissue integrity as well as the lowest liver lipid percentage and MDA content were observed in birds fed diets supplemented with poultry oil. On the other hand, feeding 30 g/kg of MTM reduced not only hepatic lipid percentage but also aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities (p < 0.01), while it improved eggshell strength and thickness (p < 0.05). Supplementation of fat powder enhanced hepatic C16:0 content, while addition of poultry, sunflower or fish oil increased C18:1, C18:2 or C20:5 concentrations respectively (p < 0.01); nonetheless, feeding the highest level of MTM reduced hepatic ΣSFA but increased Σn-3 fatty acids (p < 0.01). The interaction effects indicated that fish or sunflower oil supplementation increased the MTM level required to reduce not only serum or egg cholesterol concentrations (p < 0.05) but also blood or hepatic MDA content (p < 0.01). It was concluded that fish oil and MTM (30 g/kg) supplements might improve internal egg quality traits and eggshell quality respectively. The hepatic fatty acid profile was also found strongly correlated with dietary fatty acids. Finally, the best hepatic health indices and the highest oxidative stability were achieved when the birds were fed diets supplemented with poultry oil and 30 g/kg of MTM.
本研究评估了不同水平的奶蓟草（Silybum marianum）粉（MTM）对接受不同来源脂肪源日粮补充的产蛋鸡的蛋品质特性、氧化稳定性、血液生化参数和肝脏健康指标的影响。为此，将莱航产蛋鸡（Hy-Line W-36）随机分配到 12 个实验处理组，每组 8 个重复，每个重复 5 只鸡。日粮处理包括四种日粮脂肪源（鱼油、葵花籽油、禽油和脂肪粉，每种脂肪源的脂肪酸谱都不同）和三种 MTM 水平（0.0、15 和 30 g/kg），通过 10 天的适应期和 70 天的主要记录期提供。结果表明，日粮中添加多不饱和脂肪酸，包括鱼油或葵花籽油，降低了血清胆固醇含量，但增加了血液丙二醛（MDA）浓度（p < 0.05）。虽然鱼油改善了蛋黄颜色指数和哈夫单位（p < 0.05），但降低了蛋黄胆固醇浓度（p < 0.01）。在饲喂添加禽油日粮的鸡中，肝糖原含量最高，组织完整性最好，肝脂百分比和 MDA 含量最低。另一方面，饲喂 30 g/kg 的 MTM 不仅降低了肝脂百分比，还降低了天门冬氨酸氨基转移酶（AST）和丙氨酸氨基转移酶（ALT）活性（p < 0.01），同时提高了蛋壳强度和厚度（p < 0.05）。脂肪粉的添加增加了肝 C16:0 含量，而禽油、葵花籽油或鱼油的添加分别增加了 C18:1、C18:2 或 C20:5 的浓度（p < 0.01）；然而，饲喂最高水平的 MTM 降低了肝ΣSFA，但增加了Σn-3 脂肪酸（p < 0.01）。互作效应表明，鱼油或葵花籽油的添加增加了 MTM 的水平，不仅降低了血清或蛋黄胆固醇浓度（p < 0.05），还降低了血液或肝 MDA 含量（p < 0.01）。研究得出结论，鱼油和 MTM（30 g/kg）补充剂可能分别改善内部蛋品质特性和蛋壳质量。肝脂肪酸谱也与日粮脂肪酸密切相关。最后，当鸡饲喂添加禽油和 30 g/kg MTM 的日粮时，获得了最佳的肝健康指标和最高的氧化稳定性。
