Zhe Li, Krogh Uffe, Lauridsen Charlotte, Nielsen Mette Olaf, Fang Zhengfeng, Theil Peter Kappel
Key Laboratory for Animal Disease-Resistance Nutrition of China, Ministry of Education, Animal Nutrition Institute, Sichuan Agricultural University, 211 Huimin Road, Wenjiang District, Chengdu, 611130, China.
Department of Animal and Veterinary Sciences, Aarhus University, Foulum, Dk-8830, Tjele, Denmark.
J Anim Sci Biotechnol. 2023 Mar 10;14(1):42. doi: 10.1186/s40104-022-00815-y.
Dietary fat is important for energy provision and immune function of lactating sows and their progeny. However, knowledge on the impact of fat on mammary transcription of lipogenic genes, de novo fat synthesis, and milk fatty acid (FA) output is sparse in sows. This study aimed to evaluate impacts of dietary fat levels and FA composition on these traits in sows. Forty second-parity sows (Danish Landrace × Yorkshire) were assigned to 1 of 5 dietary treatments from d 108 of gestation until weaning (d 28 of lactation): low-fat control diet (3% added animal fat); or 1 of 4 high-fat diets with 8% added fat: coconut oil (CO), fish oil (FO), sunflower oil (SO), or 4% octanoic acid plus 4% FO (OFO). Three approaches were taken to estimate de novo milk fat synthesis from glucose and body fat.
Daily intake of FA was lowest in low-fat sows within fat levels (P < 0.01) and in OFO and FO sows within high-fat diets (P < 0.01). Daily milk outputs of fat, FA, energy, and FA-derived carbon reflected to a large extent the intake of those. On average, estimates for de novo fat synthesis were 82 or 194 g/d from glucose according to method 1 or 2 and 255 g de novo + mobilized FA/d according to method 3. The low-fat diet increased mammary FAS expression (P < 0.05) and de novo fat synthesis (method 1; P = 0.13) within fat levels. The OFO diet increased de novo fat synthesis (method 1; P < 0.05) and numerically upregulated mammary FAS expression compared to the other high-fat diets. Across diets, a daily intake of 440 g digestible FA minimized milk fat originating from glucose and mobilized body fat.
Sows fed diets with low-fat or octanoic acid, through upregulating FAS expression, increased mammary de novo fat synthesis whereas the milk FA output remained low in sows fed the low-fat diet or high-fat OFO or FO diets, indicating that dietary FA intake, dietary fat level, and body fat mobilization in concert determine de novo fat synthesis, amount and profiles of FA in milk.
日粮脂肪对泌乳母猪及其后代的能量供应和免疫功能很重要。然而，关于脂肪对母猪乳腺生脂基因转录、从头脂肪合成以及乳脂肪酸（FA）输出影响的知识尚少。本研究旨在评估日粮脂肪水平和FA组成对母猪这些性状的影响。40头经产母猪（丹麦长白猪×约克夏猪）从妊娠第108天至断奶（泌乳第28天）被分配到5种日粮处理中的1种：低脂对照日粮（添加3%动物脂肪）；或4种高脂日粮中的1种，添加8%脂肪：椰子油（CO）、鱼油（FO）、向日葵油（SO），或4%辛酸加4% FO（OFO）。采用三种方法从葡萄糖和体脂估计乳脂肪的从头合成。
在脂肪水平内，低脂母猪的FA日摄入量最低（P<0.01），在高脂日粮中，OFO和FO母猪的FA日摄入量最低（P<0.01）。脂肪、FA、能量和FA衍生碳的日产奶量在很大程度上反映了这些物质的摄入量。平均而言，根据方法1或2，葡萄糖从头脂肪合成的估计值为82或194克/天，根据方法3，从头合成+动员的FA为255克/天。在脂肪水平内，低脂日粮增加了乳腺FAS表达（P<0.05）和从头脂肪合成（方法1；P=0.13）。与其他高脂日粮相比，OFO日粮增加了从头脂肪合成（方法1；P<0.05），并在数值上上调了乳腺FAS表达。在所有日粮中，每日摄入440克可消化FA可使源自葡萄糖和动员体脂的乳脂肪量降至最低。
饲喂低脂或辛酸日粮的母猪通过上调FAS表达增加了乳腺从头脂肪合成，而饲喂低脂日粮或高脂OFO或FO日粮的母猪乳FA输出仍然较低，这表明日粮FA摄入量、日粮脂肪水平和体脂动员共同决定了从头脂肪合成、乳中FA的量和组成。
