College of Food Science and Engineering, Qingdao Agricultural University, Qingdao 266109, China; Anhui Province Key Laboratory of Livestock and Poultry Product Safety Engineering, Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei 230031, China.
Anhui Province Key Laboratory of Livestock and Poultry Product Safety Engineering, Institute of Animal Science and Veterinary Medicine, Anhui Academy of Agricultural Sciences, Hefei 230031, China.
J Dairy Sci. 2021 Jan;104(1):1164-1174. doi: 10.3168/jds.2020-18340. Epub 2020 Oct 31.
Colostrum is a unique resource that contributes to the passive transfer of immunity and plays a central role in the health status of neonatal ruminants. However, digestion and absorption of colostral proteins in the gut remain incompletely understood. Therefore, this study aimed to investigate the effect of bovine colostrum feeding on blood metabolic traits and to quantify colostral bioactive proteins in the gastrointestinal digesta and blood to evaluate intestinal transfer in neonatal lambs in the first 24 h of life. Fifty-four newborn lambs were used in this study, including 27 lambs fed pooled bovine colostrum and slaughtered at 6 (C6h), 12 (C12h), or 24 h (C24h) after birth; 18 lambs not fed any colostrum or milk and slaughtered at birth (N0h) or 24 h (N24h) after birth; and 9 milk-fed lambs slaughtered at 24 h (M24h) after birth. Lambs receiving colostrum or milk were bottle-fed within the first 2 h to obtain intakes of 8% of body weight at birth. Samples of blood and digesta from the abomasum, jejunum, and ileum were collected after slaughter. Serum concentrations of glucose, insulin, total protein, and aspartate aminotransferase were higher in colostrum-fed lambs than in N0h lambs. Serum concentrations of insulin, total protein, insulin-like growth factor 1, and γ-glutamyl transpeptidase were higher in C24h lambs than in N24h or M24h lambs. Apparent efficiencies of IgG absorption in C6h, C12h, and C24h lambs were 14.4, 26.8, and 17.2%, respectively, whereas apparent efficiencies of lactoferrin (LF), α-lactalbumin (α-LA), and β-lactoglobulin (β-LG) absorption were very low in colostrum-fed lambs, with mean values of 0.06, 0.002, and 0.003%, respectively. Concentrations of IgG, LF, α-LA, and β-LG in the digesta of the abomasum, jejunum, and ileum rapidly decreased from C6h to C24h lambs, and the disappearance rates of IgG, LF, α-LA, and β-LG were higher in lambs from C6h to C12h (62.1, 75.7, 91.3, and 95.0% for IgG, LF, α-LA, and β-LG, respectively) than from C12h to C24h (34.6, 22.5, 7.5, and 2.2% for IgG, LF, α-LA, and β-LG, respectively). These results indicated that bovine colostrum feeding improved the metabolic and immunological status of lambs, and that ingested colostral IgG was prone to intact uptake into the blood, whereas almost all ingested LF, α-LA, and β-LG disappeared in the lumen of the gastrointestinal tract in a time-dependent manner. The findings provide novel information for exploring selective absorption of colostral compounds in the small intestine of lambs.
初乳是一种独特的资源，有助于被动传递免疫力，并在新生反刍动物的健康状况中发挥核心作用。然而，肠道中初乳蛋白的消化和吸收仍不完全清楚。因此，本研究旨在研究牛初乳喂养对血液代谢特征的影响，并定量检测胃肠道消化物和血液中的初乳生物活性蛋白，以评估新生羔羊在生命的头 24 小时内的肠道转移情况。本研究使用了 54 只新生羔羊，包括 27 只喂食混合牛初乳并在出生后 6 小时（C6h）、12 小时（C12h）或 24 小时（C24h）屠宰的羔羊；18 只未喂食任何初乳或牛奶并在出生时（N0h）或出生后 24 小时（N24h）屠宰的羔羊；以及 9 只在出生后 24 小时（M24h）接受牛奶喂养的羔羊。接受初乳或牛奶喂养的羔羊在出生后的头 2 小时内通过奶瓶喂养，以获得相当于体重 8%的摄入量。屠宰后采集血液和来自皱胃、空肠和回肠的消化物样本。与 N0h 羔羊相比，初乳喂养的羔羊血清中葡萄糖、胰岛素、总蛋白和天门冬氨酸氨基转移酶浓度更高。与 N24h 或 M24h 羔羊相比，C24h 羔羊的血清胰岛素、总蛋白、胰岛素样生长因子 1 和γ-谷氨酰转肽酶浓度更高。C6h、C12h 和 C24h 羔羊 IgG 吸收的表观效率分别为 14.4%、26.8%和 17.2%，而初乳喂养羔羊的乳铁蛋白（LF）、α-乳白蛋白（α-LA）和β-乳球蛋白（β-LG）吸收的表观效率非常低，平均值分别为 0.06%、0.002%和 0.003%。皱胃、空肠和回肠消化物中 IgG、LF、α-LA 和 β-LG 的浓度从 C6h 到 C24h 羔羊迅速下降，C6h 到 C12h 羔羊 IgG、LF、α-LA 和 β-LG 的消失率（分别为 62.1%、75.7%、91.3%和 95.0%）高于 C12h 到 C24h 羔羊（分别为 34.6%、22.5%、7.5%和 2.2%）。这些结果表明，牛初乳喂养改善了羔羊的代谢和免疫状态，摄入的初乳 IgG 易于完整吸收进入血液，而几乎所有摄入的 LF、α-LA 和 β-LG 均以时间依赖性方式在胃肠道腔中消失。这些发现为探索羔羊小肠中初乳化合物的选择性吸收提供了新的信息。
