Department of Animal Nutrition and Dietetics, University of Agriculture in Krakow, al. Mickiewicza 24/28, 30-059 Krakow, Poland.
Department of Animal Nutrition and Dietetics, University of Agriculture in Krakow, al. Mickiewicza 24/28, 30-059 Krakow, Poland.
J Dairy Sci. 2019 Oct;102(10):8862-8873. doi: 10.3168/jds.2018-16189. Epub 2019 Aug 14.
The aim of this study was to determine the effect of docosahexaenoic acid-rich algae (DHA-RA) supplementation in milk replacer (MR) on performance, selected cytokine expression in lymphocytes, and blood immunoglobulin concentration in newborn dairy calves. Forty female Holstein-Friesian calves (8.6 ± 0.8 d old and 41.1 ± 4.3 kg; mean ± standard deviation) were blocked by date of birth and allocated into 4 experimental groups (10 animals/group): (1) not supplemented with DHA-RA, (2) supplemented with 9 g of DHA-RA/d in MR, (3) supplemented with 18 g of DHA-RA/d in MR, and (4) supplemented with 27 g of DHA-RA/d in MR. Milk replacer was fed in an amount equal to 900 g of MR powder/d (as fed), 2 times a d, for 49 d. Starter mixture (SM) was fed ad libitum beginning on d 15 of the study. Each calf was in the study over a period of 49 d. The MR and SM intake and fecal score were recorded daily and body weight was recorded weekly. Blood samples were collected before the morning feeding, at the beginning of the study, every consecutive week, and at the end of the study for morphology and smear analysis, serum immunoglobulin level (IgG, IgA, and IgM), and lymphocyte isolation. The mRNA isolated from lymphocytes was checked for TNFα, IL-1β, IL-6, and p65 expression. Average daily gain between d 1 to 14 of the study increased quadratically with increasing dose of DHA-RA. However, average daily gain between d 15 to 49 of the study tended to linearly decrease and over the whole study linearly decreased with increasing dose of DHA-RA. The MR intake decreased linearly between d 1 to 14 of the study and over the whole study, and mean SM intake decreased quadratically with increasing dose of DHA-RA. Feed efficiency increased quadratically and fecal score decreased quadratically during the first 14 d of the study. Increasing dose of DHA-RA led to cubic changes in feed efficiency and fecal score between d 15 and 49 of the study. Overall, over the whole study period a tendency was observed for lower fecal score for the DHA-RA supplemented groups. Interleukin-1β mRNA expression decreased linearly, whereas the mRNA expression of p65 and TNFα as well as serum IgG concentration tended to decrease linearly with increasing dose of supplemental DHA-RA. No effect of group was found on IgA and IgM serum level and the majority of blood parameters. Altogether, treatment worsened production variables but seemed to have a beneficial effect on the immune system of calves.
本研究旨在确定在代乳料中添加富含二十二碳六烯酸的藻类（DHA-RA）对新生荷斯坦奶牛的生产性能、淋巴细胞中选定细胞因子表达和血液免疫球蛋白浓度的影响。40 头雌性荷斯坦-弗里森奶牛（8.6±0.8 日龄，41.1±4.3kg；平均值±标准差）按出生日期分组，并分为 4 个实验组（每组 10 头动物）：（1）不添加 DHA-RA，（2）在代乳料中添加 9g/d DHA-RA，（3）在代乳料中添加 18g/d DHA-RA，（4）在代乳料中添加 27g/d DHA-RA。代乳料以 900g/d（实际喂入量）的量，2 次/d 饲喂，共 49d。从研究的第 15 天开始，自由采食开食料。每头小牛的研究时间为 49d。在研究期间，每天记录代乳料和开食料的摄入量和粪便评分，每周记录体重。在研究开始时、每周连续记录和研究结束时，在早上喂食前采集血样进行形态和涂片分析、血清免疫球蛋白水平（IgG、IgA 和 IgM）和淋巴细胞分离。检查从淋巴细胞中分离出的 mRNA 中 TNFα、IL-1β、IL-6 和 p65 的表达。研究第 1 天至第 14 天的平均日增重随 DHA-RA 剂量的增加呈二次曲线增加。然而，研究第 15 天至第 49 天的平均日增重呈线性趋势下降，整个研究期间随 DHA-RA 剂量的增加呈线性下降。研究第 1 天至第 14 天，代乳料的摄入量呈线性下降，整个研究期间，平均开食料的摄入量随 DHA-RA 剂量的增加呈二次曲线下降。在研究的前 14d 内，饲料效率呈二次曲线增加，粪便评分呈二次曲线下降。在研究的第 15 天至第 49 天，随着 DHA-RA 剂量的增加，饲料效率和粪便评分呈立方变化。总的来说，在整个研究期间，添加 DHA-RA 的组粪便评分呈下降趋势。白细胞介素-1β mRNA 表达呈线性下降，而 p65 和 TNFα 的 mRNA 表达以及血清 IgG 浓度随补充 DHA-RA 的剂量呈线性下降。各组间血清 IgA 和 IgM 水平和大多数血液参数均无差异。总的来说，治疗组的生产性能变差，但似乎对小牛的免疫系统有有益的影响。
