| In this experiment,540 male and female chicklings of 1-day-old were selected respectively and reared separately .3X3 factorial experiment was designed. Broilers were fed with 9 diets which were corn-fish meal -soybean meal type under different matabolizable(ME) and crude protein(CP). The effects on the performances and carcass ingredients of the first growing period(0-4 week) ,the middle growing period (4-8 week)and the finish period (9-12 week) Gushi chickens under different ME and CP concentrations were studied by rearing ,comparative slaughter and metabolism experiments. According to the results of three experiments , optimal ME and CP levels in each period diets of Gushi chickens were found out. ME and CP levels of each period diets were designed as follows:the first growing period: ME: 11.97MJ/Kg, 12.34MJ/Kg, 12.72MJ/Kg,CP: 19.12%, 20.02%, 21.04%;the middle growing period: ME: 12.38MJ/Kg, 12.71MJ/Kg, 13.02MJ/Kg,CP: 17.12%, 18.09%, 19.07%;the finish period: ME: 12.40MJ/Kg, 12.74MJ/Kg, 13.03MJ/Kg,CP: 15.04%, 16.02%, 17.02%.The metabolism experiment showed that the dietary ME according to the tables of feed composition and nutritive value in China were lower than measured values. Comparing with low ME trials, high ME trials were nearer calculated values.The rearing experiments showed as follows:(1) Feed Intake. ME and CP factors had significant influence on the male during the first period (P<0.05), and no significant influence during the middle period (P>0.05), and only ME levels had significant influence during the finish period (P<0.05); As for the female, ME factor had significant effect on feed intake in each period (PO.05), and CP factor had little influence. The interaction between ME and CP had no significant effect on the male and female in each period. (2) Body Gain. During the first period ME and CP factors had significant influence on the male (P<0.01), but the interaction between ME and CP had no significant effect on the male and female. The average body gain of the male was improved with the increase of ME and CP, and the diet with high ME and high CP was the best. So were the female, but no significant influence (P>0.05); During the middle period none of ME , CP and their interaction had significant effect on male and female(P>0.05),and from CP factor, the trials with middle CP level were better for male and female; During the finish period none of ME and CP and their interaction had significant effect on male and female(P>0.05), and the diet with high ME and CP was the best for the male. As for the female, the reaction were similar with the middle period's, but compared with the middle period the body gain declined. (3) Feed/Gain. ME and CP factors had significant influence on the male during the first period (P<0.01), Feed/Gain decreased with the increase of ME and CP levels; ME factor hadsignificant influence (P<0.01) while CP factor had little influence on the female. Feed/Gain decreased with the increase of ME levels. During the middle period ME and CP and their interaction had no significant effect on male (P>0.05) while only ME factor had significant influence on the female (P<0.05). As a whole, the trials with middle CP level had lower Feed/Gain During the finish period ME and CP factors had little effect on male and female (P>0.05). The interaction between ME and CP had no significant effect on the male and female in each period.The comparative slaughter experiment showed: energy, crude protein and fat concentrations in Gushi chickens live body improved with the week-old. But moisture was opposite. Dry material, ether extract, crude protein and energy concentrations of the female were higher that that of the male the same week-age. But ME and CP factors had no significant effect on carcass ingredients of the male and female (P>0.05).The formulas drawn from the three experiments were as follows: ME requirements formulas of each period:0-4 week ♂ ME=370.34W075+9.58AW ♀ ME=355.15W075+11.08AW 5-8 week...
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