Rogers S R, Pesti G M
Department of Poultry Science, University of Georgia, Athens 30602.
Poult Sci. 1990 May;69(5):746-56. doi: 10.3382/ps.0690746.
Three experiments were conducted to determine how dietary protein and tryptophan influence the lipid metabolism of growing broiler chicks. A diet-dilution method (corn-corn gluten meal-gelatin summit/corn starch basal) was used in three factorial experiments. Various levels of protein and tryptophan were fed in each experiment: protein from 16 to 28% and tryptophan from .34 to 2.74% of protein. Gain was maximized when the dietary levels of tryptophan were .83 +/- .03, 77 +/- .04, 77 +/- .05, and .78 +/- .05% of the protein for 16, 20, 24, and 28% dietary protein, respectively. The requirement estimates for feed efficiency and gain were similar. Liver lipids significantly decreased as the level of dietary tryptophan increased at each protein level (P less than .0001). Dietary tryptophan did not significantly alter the concentration of total plasma lipid in the chicks or in the carcass lipid content (P greater than .2399). Tryptophan supplementation significantly increased the concentration of plasma linoleic acid and plasma free tryptophan. The requirement of the chicks for tryptophan was estimated to be .80 +/- .01% of the dietary protein for the growing chick. Increased liver lipid and decreased plasma tryptophan are diagnostic lesions suggesting a tryptophan deficiency.
进行了三项试验以确定日粮蛋白质和色氨酸如何影响生长肉鸡的脂质代谢。在三项析因试验中采用了日粮稀释法（玉米-玉米蛋白粉-明胶/玉米淀粉基础日粮）。每项试验中饲喂不同水平的蛋白质和色氨酸：蛋白质含量从16%至28%，色氨酸含量为蛋白质的0.34%至2.74%。当日粮色氨酸水平分别为16%、20%、24%和28%日粮蛋白质的0.83±0.03%、0.77±0.04%、0.77±0.05%和0.78±0.05%时，增重达到最大值。饲料效率和增重的需求估计值相似。在每个蛋白质水平下，随着日粮色氨酸水平的升高，肝脏脂质显著降低（P＜0.0001）。日粮色氨酸对雏鸡血浆总脂质浓度或胴体脂质含量没有显著影响（P＞0.2399）。补充色氨酸显著提高了血浆亚油酸和血浆游离色氨酸的浓度。生长雏鸡色氨酸的需求量估计为日粮蛋白质的0.80±0.01%。肝脏脂质增加和血浆色氨酸降低是提示色氨酸缺乏的诊断性病变。
