Blauwiekel R, Xu S, Harrison J H, Loney K A, Riley R E, Calhoun M C
Department of Animal Sciences, Washington State University, Puyallup 98371-4998, USA.
J Dairy Sci. 1997 Jul;80(7):1358-65. doi: 10.3168/jds.S0022-0302(97)76064-8.
To determine whether the gossypol content of the diet affected availability of dietary Lys, 4 cows with ruminal and duodenal cannulas and 16 intact cows in early lactation were assigned to diets containing either glanded cottonseed, glanded cottonseed plus 15 g/d of ruminally protected Lys, glandless cottonseed, or glandless cottonseed plus 15 g/d of ruminally protected Lys. The experimental design was a 4 x 4 Latin square design with 3-wk experimental periods. Gossypol concentrations in plasma were lower when cows were fed glandless cottonseed. Lysine supplementation increased the flow and percentage of Lys in duodenal digesta and increased the concentration of Lys in plasma. Neither type of cottonseed nor Lys supplementation affected dry matter intake. Yields of milk and fat-corrected milk from cannulated cows were not affected by diet, but yields from intact cows were increased by Lys supplementation. For both cannulated and intact cows, Lys supplementation increased the percentage of milk protein, and milk protein yield was increased by Lys in intact cows. Dietary gossypol did not affect the response to Lys, indicating that dietary gossypol had little or no effect on the availability of Lys for dairy cows.
为了确定日粮中棉酚含量是否会影响日粮赖氨酸的利用率，将4头装有瘤胃和十二指肠瘘管的奶牛以及16头处于泌乳早期的未插管奶牛分配至含有带腺体棉籽、带腺体棉籽加15克/天瘤胃保护性赖氨酸、无腺体棉籽或无腺体棉籽加15克/天瘤胃保护性赖氨酸的日粮组。试验设计为4×4拉丁方设计，试验期为3周。给奶牛饲喂无腺体棉籽时，血浆中的棉酚浓度较低。补充赖氨酸增加了十二指肠食糜中赖氨酸的流量和比例，并提高了血浆中赖氨酸的浓度。两种类型的棉籽以及补充赖氨酸均未影响干物质采食量。瘘管奶牛的产奶量和校正乳产量不受日粮影响，但未插管奶牛的产奶量因补充赖氨酸而增加。对于瘘管奶牛和未插管奶牛，补充赖氨酸均提高了乳蛋白百分比，且未插管奶牛的乳蛋白产量因赖氨酸而增加。日粮棉酚不影响对赖氨酸的反应，表明日粮棉酚对奶牛赖氨酸的利用率几乎没有影响。
