Picklo Matthew J, Kalscheur Kenneth F, Magnuson Andrew, Bukowski Michael R, Harnly James, Fukagawa Naomi K, Finley John W
USDA-Agricultural Research Service (USDA-ARS) Grand Forks Human Nutrition Research Center, Grand Forks, ND, USA.
USDA-ARS Dairy Forage Research Center, Madison, WI, USA.
Curr Dev Nutr. 2022 Jan 28;6(2):nzab154. doi: 10.1093/cdn/nzab154. eCollection 2022 Feb.
Branched-chain fatty acids (BCFAs) are rumen-derived fatty acids comprising ∼2% of bovine-milk fatty acids. BCFAs possess anti-inflammatory properties and enriching the BCFA content of bovine milk may provide human health benefits.
We determined whether forage content impacts the BCFA content of milk from Holstein cows and identified fatty acid phenotypes in high vs. low BCFA-containing milks.
Holstein cows ( = 62), fed for 67 d in a crossover design, consumed a diet with high forage and low concentrate (HF:C) and a diet with low forage and high concentrate (LF:C). Milk samples were collected at the end of each treatment period and fatty acid content determined. Paired t-tests, 1-factor ANOVA, sparse partial least-squares discriminant analysis (sPLSDA), and Pearson's correlation analysis were used to analyze the data.
The total milk fatty acid concentration for cows fed the HF:C diet was greater than that of cows fed the LF:C diet (4.2 ± 0.7 g/100 mL vs. 3.9 ± 0.9 g/100 mL). sPLSDA demonstrated separation of the dietary treatments, with BCFAs and odd-chain fatty acids as primary determinants. Total BCFA content in milk fat was elevated by HF:C intake compared with LF:C intake (1.80 vs. 1.68%). Quintile separation of high vs. low BCFA milks resulted in 4 groups: HF:C /low BCFAs, HF:C /high BCFAs; LF:C /low BCFAs, and LF:C /high BCFAs. Milks from the high BCFA quintiles had lower palmitic acid content (29.6% vs. 34.4%) but higher oleic acid content than milks from the low BCFA quintiles (19.7% vs. 17.0%). Some cows were identified as high BCFA producers or low BCFA producers regardless of diet.
BCFA content of milk is diet-sensitive but variation in responses exists. The potential to produce milk with high BCFA content and lower SFA content needs further study.
支链脂肪酸（BCFAs）是源自瘤胃的脂肪酸，占牛乳脂肪酸的约2%。BCFAs具有抗炎特性，提高牛乳中的BCFA含量可能对人类健康有益。
我们确定了饲草含量是否会影响荷斯坦奶牛牛奶中的BCFA含量，并识别了高BCFA含量牛奶与低BCFA含量牛奶中的脂肪酸表型。
采用交叉设计，对62头荷斯坦奶牛进行67天的饲养，分别给它们饲喂高饲草低精料（HF:C）日粮和低饲草高精料（LF:C）日粮。在每个处理期结束时采集牛奶样本，并测定脂肪酸含量。使用配对t检验、单因素方差分析、稀疏偏最小二乘判别分析（sPLSDA）和皮尔逊相关分析对数据进行分析。
饲喂HF:C日粮的奶牛的总乳脂肪酸浓度高于饲喂LF:C日粮的奶牛（4.2±0.7 g/100 mL对3.9±0.9 g/100 mL）。sPLSDA显示了日粮处理的分离，其中BCFAs和奇数链脂肪酸是主要决定因素。与LF:C日粮相比，HF:C日粮使乳脂肪中的总BCFA含量升高（1.80%对1.68%）。将高BCFA牛奶与低BCFA牛奶按五分位数分开，得到4组：HF:C/低BCFAs、HF:C/高BCFAs；LF:C/低BCFAs和LF:C/高BCFAs。高BCFA五分位数的牛奶中棕榈酸含量较低（29.6%对34.4%），但油酸含量高于低BCFA五分位数的牛奶（19.7%对17.0%）。无论日粮如何，一些奶牛被鉴定为高BCFA生产者或低BCFA生产者。
牛奶中的BCFA含量对日粮敏感，但存在反应差异。生产高BCFA含量和低饱和脂肪酸（SFA）含量牛奶的潜力需要进一步研究。
