Trine F. Pedersen，Thomas S. Bruun，Nathalie L. Trottier，Peter K. Theil
翻譯&校對：上海亙泰實業集團

這項研究的目的是：1）量化日糧中氮（N）用于乳汁中N利用和尿液、糞便中的N損失，母豬飼喂的日糧中粗蛋白（CP）水平增加，但是為了滿足其標準化回腸消化率（SID）的需求，賴氨酸、蛋氨酸和蘇氨酸、色氨酸的含量保持不變。2）根據日糧N被分泌的乳汁利用情況，確定最佳的日糧CP濃度。

試驗選用72頭泌乳母豬，隨機分到1～6組處理組中的一組，按照SID CP水平配制飼料配方，SID CP水平分別為：11.8、12.8、13.4、14.0、14.7、15.6%，各處理組日糧能量一致（9.8 MJ NE/kg）。試驗日糧從母豬分娩后第二天開始飼喂，到28d（±3d）斷奶結束，每窩仔豬等量為14頭，出生48h內稱重。分別在泌乳18d（±3d）和28d（±3d）對母豬進行稱重和檢測背膘值；分別在哺乳11、18（±3d）和28（±3d）稱量記錄窩仔豬重量；在泌乳4、11、和18（±3d）進行N平衡統計分析；日產奶量由窩增重和窩仔數評估；為了計算母豬機體脂肪和蛋白的調動，在泌乳4和18d（±3d）用氘水（D2O）濃縮方法評估機體內脂肪和蛋白蓄積。

試驗結果表明，在泌乳的第一周、第二周和第三周，隨著日糧中CP水平的增加，乳汁中蛋白含量呈線性關系升高（P < 0.05、P < 0.05和P < 0.001）；同樣的，隨著日糧中CP水平的增加，第一周、第二周和第三周的尿N值呈直線升高（P = 0.05、P < 0.001和P < 0.001）；各日糧組間尿液排放沒有差異。相對于N攝入量，隨著日糧CP增加，尿N排放呈直線增加（P < 0.001）；從日糧處理組1到6，乳汁中N利用率從77.8%直線下降到63.1%（P< 0.001）；校正后乳汁中N利用率從68.6%下降到64.2%（P< 0.05）

綜上所述，哺乳母豬日糧中含低CP水平，添加晶體氨基酸能夠在不影響母豬泌乳性能的情況下提高日糧N利用率，減少尿氮排放。


Nitrogen utilization of lactating sows fed increasing dietary protein

The objectives of the study were 1) to quantify dietary N utilized for milk N and N loss in urine and feces, in sows fed increasing dietary CP with a constant amount of Lys, Met, Thr, and Trp to meet their standardized ileal digestible (SID) requirement and 2) to determine the optimal dietary CP concentration based on dietary N utilization for milk production. Seventy-two sows were fed 1 of 6 dietary treatments, formulated to increase the SID CP as followed: 11.8, 12.8, 13.4, 14.0, 14.7, and 15.6% and formulated to be isocaloric (9.8 MJ NE/kg). Diets were fed from day 2 after parturition until weaning at day 28 (± 3 d). Litters were equalized to 14 piglets and weighed within 48 h following parturition. Sows were weighed and back fat scanned, at day 18 (± 3 d) and day 28 (weaning; ± 3 d). Litter weight was recorded at day 11, 18 (± 3 d), and 28 (± 3 d). Nitrogen balances were conducted on approximately day 4, 11, and 18 (± 3 d). Daily milk yield was estimated from recorded litter gain and litter size. To calculate sows mobilization of fat and protein, body pools of fat and protein were estimated by D2O (deuterated water) enrichment on day 4 and 18 (± 3 d). No linear, quadratic, or cubic effects of increasing dietary CP was observed for sows total feed intake, sow BW, body pools of protein and fat, protein and fat mobilization, total milk yield, and piglet performance. The protein content in milk increased linearly with increasing dietary CP in week 1 (P < 0.05), week 2 (P < 0.05), and week 3 (P < 0.001). Urine production did not differ among treatments and N output in urine increased linearly with increasing dietary CP concentration in week 1 (P= 0.05), week 2 (P < 0.001), and week 3 (P < 0.001). Urine N excretion relative to N intake increased linearly with increasing dietary CP (P <0.001). Milk N utilization relative to N intake decreased linearly from 77.8% to 63.1% from treatment 1 through 6 (P < 0.001). Corrected milk N utilization decreased from 68.6% to 64.2% from treatment 1 through 6 (P < 0.05). In conclusion, a low dietary CP concentration for lactating sows with supplemented crystalline AA improved the efficiency of dietary N utilization and reduced the N output in urine without affecting lactation performance.（轉自：豬營養國際論壇）