EFFECTS OF CRUDE PROTEIN LEVELS ON GROWTH PERFORMANCE, NITROGEN BALANCE, DIGESTIBILITY AND CRUDE PROTEIN REQUIREMENT OF GROWING FUXING PIGS

The purpose of this study was to determine the protein requirements of growing Fuxing pig, and to provide basic parameters for determining the feeding standards of growing Fuxing pig. In this experiment, a single factor randomized block design was used, and forty healthy weaned pigs with a body weight of (20.45 +/- 1.65kg) were randomly selected and divided into 4 groups, with 10 pigs in each group. Each group was fed diets with CP levels (CP12, CP14, CP16, CP18) during the 67 days feeding trail, the 7 days preliminary experimental period and the 60 days experimental period. Three healthy pigs were randomly selected from each group. Before the last 7 days of the experiment, all urine and feces were collected to determine the nutritional digestibility and metabolic. The results showed that the addition of CP16 to the diet could reduce the F/G. The CP16 group decreased by 8%, 6.9%, and 3.7% compared with that of the CP12, CP14, and CP18 groups, respectively. There was no difference between the CP16 and CP18 groups (P>0.05). The digestibility of EE in the CP16 and CP18 groups was significantly higher than that in the CP12 group (P <= 0.05). There was no significant difference between the CP14, CP16, and CP18 groups (P>0.05). With the increase of the crude protein level, the digestibility of EE in the CP, DCP (digestible crude protein) CP16 and CP18 groups was significantly higher than that of the CP12 group, CP14 group (P <= 0.01), CP16 group. In the case of the CP12 group and the CP14 group, NI (nitrogen intake), UN (urine nitrogen), RN (retention nitrogen), N%, were all significantly higher. To sum, Fuxing pig DCP intake was used as the dependent variable (Y) and ADG as the independent variable (X) for linear regression analysis. The digestible CP requirement the regression equation with Fuxing pig's growing period was as follows: DCP=1.93 W-0.75+0.34 Delta W (DCP: g/d;W-0.75: kg;Delta W: g/d).