試驗一，30頭母豬，處理間母豬胎次一致，每頭母豬帶仔12頭。試驗處理為6%動植物混合油（A-V），6%精煉油（CWG）和對照組（無油脂添加）。日糧為玉米豆粕型，并添加8%玉米DDGS、6%麥麩，日糧中SID賴氨酸含量為3.25g /Mcal代謝能。日糧中添加油脂可以增加母豬奶水中脂肪的分泌量（P=0.082，559g/d VS 499g/d）。必需脂肪酸沉積以表觀回腸吸收量減去乳中分泌量計算得到。對照組哺乳母豬奶水中的亞油酸分泌量高于攝入量，導致了哺乳母豬機體亞油酸的負平衡（分娩后第3、10、17天分別為-22.4、-38.0、-14.1g/d）。
Impact of dietary lipids on sow milk composition and balance of essential fatty acids during lactation in prolific sows
D. S. Rosero, J. Odle, S. M. Mendoza, R. D. Boyd, V. Fellner and E. van Heugten
Two studies were designed to determine the effects of supplementing diets with lipid sources of EFA (linoleic and α-linolenic acid) on sow milk composition to estimate the balance of EFA for sows nursing large litters. In Exp. 1, 30 sows, equally balanced by parity (1 and 3 to 5) and nursing 12 pigs, were fed diets supplemented with 6% animal-vegetable blend (A-V), 6% choice white grease (CWG), or a control diet without added lipid. Diets were corn-soybean meal based with 8% corn distiller dried grains with solubles and 6% wheat middlings and contained 3.25 g standardized ileal digestible Lys/Mcal ME. Sows fed lipid-supplemented diets secreted greater amounts of fat (P = 0.082; 499 and 559 g/d for control and lipid-added diets, respectively) than sows fed the control diet. The balance of EFA was computed as apparent ileal digestible intake of EFA minus the outflow of EFA in milk. For sows fed the control diet, the amount of linoleic acid secreted in milk was greater than the amount consumed, throughout lactation. This resulted in a pronounced negative balance of linoleic acid (-22.4, -38.0, and -14.1 g/d for d 3, 10, and 17 of lactation, respectively). In Exp. 2, 50 sows, equally balanced by parity and nursing 12 pigs, were randomly assigned to a 2 × 2 factorial arrangement of diets plus a control diet without added lipids. Factors included linoleic acid (2.1% and 3.3%) and α-linolenic acid (0.15% and 0.45%). The different concentrations of EFA were obtained by adding 4% of different mixtures of canola, corn, and flaxseed oils to diets. The n-6 to n-3 fatty acid ratios in the diets ranged from 5 to 22. Increasing supplemental EFA increased (P < 0.001) milk concentrations of linoleic (16.7% and 20.8%, for 2.1% and 3.3% linoleic acid, respectively) and α-linolenic acid (P < 0.001; 1.1 and 1.9% for 0.15 and 0.45% α-linolenic acid, respectively). Increasing supplemental EFA increased the estimated balance of α-linolenic acid (P < 0.001; -0.2 and 5.3 g/d for 0.15% and 0.45% α-linolenic acid, respectively), but not linoleic acid (P = 0.14; -3.4 and 10.0 g/d for 2.1% and 3.3% linoleic acid, respectively). In conclusion, lipid supplementation to sow lactation diets improved milk fat secretion. The fatty acid composition of milk fat reflected the dietary supplementation of EFA. The net effect of supplemental EFA was to create a positive balance during lactation, which may prove to be beneficial for the development of nursing piglets and the subsequent reproduction of sows.