الفهرس 
acknowledgmentOnly 14 pages are availabe for public view
 |  | from | 199 |  |  |
| | | from | 199 | | |
Abstract
Protein is an essential constituent of all living matter and the demand by animals, although continuous is variable in amount Several investigators have examined the effect of dietary protein level on performance and body composition of growing chicks and poults (e.g. Klain et al, 1960; Summers et al.. 1964; Combs and Nicholson, 1965; Thomas and Combs, 1966; Blixler, et al, 1989 and Yoshida and Morimoto, 1970; a,b), ducks (Scott et al., 1959a,b; and Dean, 1967) and rats (Forbes et al., 1940; Mackay, et al., 1941; Meyer, 1958 and Marshall et al., 1969. In general, the results of these studies support the view that rate and efficiency of gain as well as carcass leanness are enhanced by increases in the level of dietary protein. The rate at which these criteria are enhanced per unit of nitrogen or protein intake provides a basis for calculating protein utilization.The concept of protein utilization as a function of protein intake originated from the early growth s and nitrogen balance studies of Mitchell .1924 Subsequent work with rats (Platt.