Departamento de Zootecnia, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, 30161-970, Brazil.
Embrapa Gado de Leite, Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA), Juiz de Fora, MG, 36038-330, Brazil.
Sci Rep. 2023 Feb 28;13(1):3378. doi: 10.1038/s41598-023-30088-y.
The objective of this study was to evaluate blood cells and metabolites, insulin-like growth factor-1 (IGF-1), digestibility, internal organs weight and histology, gene expression, and spleen cell proliferation of pre-weaned bull calves supplemented with a blend of essential oils in milk replacer (MR). Sixteen newborn Holstein × Gyr crossbred dairy bull calves, with body weight at birth of 33.3 ± 3.7 kg, were housed in individual sand bedded pens, blocked by genetic composition, and randomly assigned to 1 of 2 treatments in a randomized complete block design: Control (CON, n = 8) and blend of essential oils supplementation (BEO, n = 8, 1 g/day/calf, Apex Calf, Adisseo, China). The commercial blend was composed by plant extracts derived from anise, cinnamon, garlic, rosemary, and thyme. Animals were fed 5 L of MR/day reconstituted at 15% (dry matter basis), divided into two equal meals. Water and starter were provided ad libitum. ß-hydroxybutyrate, urea, and glucose were evaluated weekly, IGF-1 was evaluated biweekly, and total blood cell count was performed every four weeks until the end of the trial at eight weeks of age. Feed samples were collected three times a week and polled for weekly analysis. Apparent total nutrient digestibility was determined from d 56 to 60 of age. On d 60 ± 1, animals were euthanized for organ weight, histology, spleen cell proliferation, and intestinal gene expression analysis. Data were analyzed independently using linear mixed models using the REML method in the nlme package in R for continuous outcomes. A non-parametric test was used for ordered categorical outcomes using the Artools package in R. There were no differences between groups for blood evaluations, digestibility, gene expression, and a spleen cell proliferation assay. However, BEO calves presented a heavier pancreas, heavier intestines, bigger ileum villi, and higher cecum butyrate levels (P < 0.05), demonstrating that the EO supplementation helped intestinal development and symbiotic bacteria. It was also observed in CON animals' heavier respiratory tract and a higher eosinophil count (P < 0.05). Therefore, the organs where eosinophils are more active had a better response for BEO animals. No differences were found in the intestinal gene expression in the immune context. These results demonstrate that supplementing essential oils in MR could contribute to gut development and immune function. However, more research is needed to understand its impact on body development and define the best dosage and route of administration.
本研究旨在评估添加混合精油的代乳料对新生荷斯坦公牛犊血液细胞和代谢物、胰岛素样生长因子-1（IGF-1）、消化率、内脏器官重量和组织学、基因表达以及脾细胞增殖的影响。16 头初生体重为 33.3±3.7kg 的荷斯坦公牛犊，饲养在单独的沙床围栏中，按遗传组成分组，采用完全随机区组设计随机分配到 2 种处理组：对照组（CON，n=8）和混合精油添加组（BEO，n=8，每天每头 1g，Apex Calf，Adisseo，中国）。商业混合精油由茴芹、肉桂、大蒜、迷迭香和百里香的植物提取物组成。动物每天喂食 5L 代乳料（按干物质基础计算为 15%），分为两份相等的餐食。水和开食料自由采食。每周评估β-羟丁酸、尿素和葡萄糖，每两周评估 IGF-1，四周一次的全血细胞计数持续到 8 周龄试验结束。每周收集 3 次饲料样品并进行每周分析。在 56 至 60 日龄时测定养分表观总消化率。60±1 日龄时，动物安乐死，测定器官重量、组织学、脾细胞增殖和肠道基因表达分析。使用 R 中的 nlme 包中的 REML 方法对连续结果进行线性混合模型分析。使用 R 中的 Artools 包对有序分类结果进行非参数检验。两组之间的血液评估、消化率、基因表达和脾细胞增殖试验均无差异。然而，BEO 组的胰腺、肠道、回肠绒毛更大，盲肠丁酸水平更高（P<0.05），表明精油补充有助于肠道发育和共生菌。在 CON 组中还观察到呼吸道更重和嗜酸性粒细胞计数更高（P<0.05）。因此，嗜酸性粒细胞更活跃的器官对 BEO 动物的反应更好。在免疫背景下，肠道基因表达无差异。这些结果表明，在代乳料中添加精油可能有助于肠道发育和免疫功能。然而，需要进一步研究以了解其对身体发育的影响，并确定最佳剂量和给药途径。
