Simov P, Semov P
Vet Med Nauki. 1976;13(5):18-25.
Experiments were carried out with one-hundred broiler birds of one and the same age group, breed, and origin, divided into five groups in order to follow up the effect of various amounts of urea on their physiologic state. A balance experiment was conducted to establish the effect of urea on the digestibility of nutrient matter and the metabolism of nitrogen with the use of nine birds per group, divided into three subgroups. Urea was added to a protein-balanced diet from the 20th to the 60th day in the following amounts by groups: I--2 percent; II--4 per cent; III--5 per cent; and IV--6 per cent. It was also found that with the increase of urea in the ration at the rates indicated above there was a progressive rise of both the amount of urea and the nonprotein nitrogen in the blood as well as the amount of nitrogen excreted with the urine. The intake of such amounts of urea lowered the assimilation of nitrogen by 4 to 9 per cent as against its initial level in the ration, and by 7 to 11 per cent--as against the level of digested nitrogen.
选用100只同龄、同品种、同来源的肉鸡进行实验，将其分为五组，以追踪不同量尿素对其生理状态的影响。进行了一项平衡实验，每组使用9只鸡，分为三个亚组，以确定尿素对营养物质消化率和氮代谢的影响。从第20天到第60天，按以下量向蛋白质平衡日粮中添加尿素：第一组——2%；第二组——4%；第三组——5%；第四组——6%。还发现，随着日粮中尿素以上述比例增加，血液中尿素和非蛋白氮的含量以及随尿液排出的氮量都逐渐增加。摄入这些量的尿素使氮的同化量比日粮初始水平降低了4%至9%，比消化氮水平降低了7%至11%。
