Trottier N L, Shipley C F, Easter R A
Department of Animal Sciences, University of Illinois, Urbana 61801, USA.
J Anim Sci. 1997 May;75(5):1266-78. doi: 10.2527/1997.7551266x.
The objectives of this study were to measure arteriovenous concentration (A-V) differences and estimate uptake of amino acids across the mammary gland in lactating sows. Four sows were used in Trial 1 and nine sows in Trial 2. Cannulas were fitted in the right anterior mammary vein and the carotid artery around d 7 of lactation. Arteriovenous samples were obtained on d 11, 14, 17, and 20. Litters were separated from the sows for 90 min, after which the first blood samples were drawn. Samples were taken at 20-min intervals for the next two consecutive hours. Milk production measurements and milk samples were obtained between d 11 and 19. Liters of plasma to liters of milk ratio (conversion coefficient) was estimated with the Fick method using A-V difference for lysine and milk lysine concentration. The conversion coefficient and the daily plasma flow were 541.41 +/- 35.72 L of plasma per liter of milk and 4,275 +/- 386 L of plasma, respectively. The A-V differences and the plasma flow were used to quantify daily amino acid uptake by the mammary gland. Uptake estimates (grams/day) were 36.51 +/- 4.05 (leucine), 31.24 +/- 3.64 (arginine), 23.39 +/- 2.97 (lysine), 21.22 +/- 1.96 (valine), 18.36 +/- 1.92 (isoleucine), 15.9 +/- 1.9 (threonine), 15.46 +/- 1.58 (phenylalanine), 7.61 +/- 1.12 (histidine), and 6.54 +/- 2.01 (methionine). The uptakes of arginine, leucine, isoleucine, valine, phenylalanine, and threonine significantly exceeded output of these amino acids in the milk. These results indicate that the sow mammary gland retains specific amino acids above requirements for milk protein synthesis.
本研究的目的是测量泌乳母猪乳腺的动静脉浓度（A-V）差异，并估计氨基酸在乳腺中的摄取量。试验1使用了4头母猪，试验2使用了9头母猪。在泌乳第7天左右，在右前乳腺静脉和颈动脉中植入套管。在第11、14、17和20天采集动静脉样本。仔猪与母猪分开90分钟，之后采集第一份血样。在接下来的连续两个小时内，每隔20分钟采集一次样本。在第11天至19天期间进行产奶量测量并采集奶样。使用赖氨酸的A-V差异和奶中赖氨酸浓度，通过菲克法估计血浆升数与奶升数的比率（转换系数）。转换系数和每日血浆流量分别为每升奶541.41±35.72升血浆和4275±386升血浆。A-V差异和血浆流量用于量化乳腺每日的氨基酸摄取量。摄取量估计值（克/天）分别为：亮氨酸36.51±4.05、精氨酸31.24±3.64、赖氨酸23.39±2.97、缬氨酸21.22±1.96、异亮氨酸18.36±1.92、苏氨酸15.9±1.9、苯丙氨酸15.46±1.58、组氨酸7.61±1.12、蛋氨酸6.54±2.01。精氨酸、亮氨酸、异亮氨酸、缬氨酸、苯丙氨酸和苏氨酸的摄取量显著超过了这些氨基酸在奶中的输出量。这些结果表明，母猪乳腺保留的特定氨基酸超过了奶蛋白合成所需的量。
