Qiu Qinghua, Gao Chaoyu, Su Huawei, Cao Binghai
State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
Animal Nutrition and Feed Safety Innovation Team, Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, College of Animal Science and Technology, Jiangxi Agricultural University, Nanchang 330045, China.
Animals (Basel). 2021 Jul 23;11(8):2192. doi: 10.3390/ani11082192.
This study was conducted to explore the proper time required to achieve stabilization in digestibility, serum metabolism, and rumen fermentation characteristics when different diets shift, thus providing decision-making of practical sampling frequency for basal nutritional research. For these purposes, 12 Holstein steers (body weight 467 ± 34 kg, age 14 ± 0.5 months) were equally assigned to two dietary treatments: high-density (metabolizable energy (ME) = 2.53 Mcal/kg and crude protein (CP) = 119 g/kg; both ME and CP were expressed on a dry matter basis) or low-density (ME = 2.35 Mcal/kg and CP = 105 g/kg). The samples of feces, serum, and rumen contents were collected with a 30-day interval. All data involved in this study were analyzed using the repeated measures in mixed model of SPSS. Results showed that nutrient apparent digestibility and serum metabolic parameters were stable across each monthly collection, while most rumen fermentation characteristics, namely concentrations of acetate, propionate, isobutyrate, and valerate, were affected by the interaction effects between collection period and dietary density. These findings indicate that rumen fermentation characteristics require more time to stabilize when diet shifts. It is recommended to collect ruminal digesta monthly to evaluate rumen fermentation characteristics, while unnecessary to sample monthly for digestion trials and blood tests in the long-term fattening of Holstein steers. This study may provide insights into exploring the associations between detected parameters and stabilization time, and between diet type and stabilization time when diet shifts.
本研究旨在探讨不同日粮转换时，在消化率、血清代谢和瘤胃发酵特性方面达到稳定所需的合适时间，从而为基础营养研究中实际采样频率的决策提供依据。为此，将12头荷斯坦公牛（体重467±34千克，年龄14±0.5个月）平均分为两种日粮处理：高密度（代谢能（ME）=2.53兆卡/千克，粗蛋白（CP）=119克/千克；ME和CP均以干物质为基础表示）或低密度（ME=2.35兆卡/千克，CP=105克/千克）。粪便、血清和瘤胃内容物样本每隔30天采集一次。本研究涉及的所有数据均使用SPSS混合模型中的重复测量进行分析。结果表明，每月采集的营养物质表观消化率和血清代谢参数均稳定，而大多数瘤胃发酵特性，即乙酸、丙酸、异丁酸和戊酸的浓度，受采集期和日粮密度之间的交互作用影响。这些发现表明，日粮转换时瘤胃发酵特性需要更多时间才能稳定。建议每月采集瘤胃消化物以评估瘤胃发酵特性，而在荷斯坦公牛的长期育肥过程中，无需每月进行消化试验和血液检测采样。本研究可能为探索日粮转换时检测参数与稳定时间之间以及日粮类型与稳定时间之间的关联提供见解。
