| Five experiments were conducted to determine dynamic growth model of broilers by use of nutrition partition principle and lysine requirement model.Experiment 1 Model for the maximum body protein deposition of broilerTwo hundreds of AA broilers were selected to simulate the relationship of live weight and body protein. All broilers were supplied the same balanced diet and ideal environment.Daily body protein deposition could be seen as a reasonable close to maximum body protein deposition. Power function combined Gompertz function can get a better result. The final models were showed as follows:Pdmax=Pd=C*a*b*EBWb*In(A/EBW)=0.036*0.1166*1.0639*LBW1.0639*In(61 30.87/LBW (male)Pdmax=Pd=0.045*0.1168*1.0615*LBW1.0615*In(3965.15/LBW) (female)Experiment 2 Models for feed intake, protein and live weight, relationship of body composition of broilerMathematics models of feed intake, body protein and live weight, relationship of body composition are the necessary composition of dynamic growth model. Two hundreds of AA broilers were selected to determinate parameters of models. The results indicated: power function has a better effect. The model of predicting feed intake by live weight is FI=0.556*LBW0.75(male), FI=0.5313*LBW0.75(female). The model of predicting feed intake by metabolism energy is FI=MEI/MEp= (7.2394*LBW0.75)/MEp (male), FI=MEI/MEp= (6.9169*LBW075)/MEp(female) MEp is metabolism energy in feed .The relationship of body protein and live weight is Pt =0.1592 (LBW1.0258) (male), Pt =0.1479 (LBW1.0319) (female). The relationship of body water and body protein is WAt=7.2756 (Pt0.8775) (male), WAt=7.1274 (Pt0.8814) (female).The relationship of body ash and body protein is Asht=0.1446 (Pt1.0225) (male), Asht=0.1427 (Pt1.0332) (female). The relationship of body fat and body protein is Lt=0.3662 (Pt1.0214) (male),Lt=0.2761 (Pt1.1238) (famale).Experiment 3 Validation of dynamic growth model of broilerThe trial was designed to evaluate effectiveness and practicality of dynamic growing model. Four hundreds of AA broilers were selected to feed two different nutrition level feed. The growth model was debugged and validated in the experiment. In the debug process, different formulations and parameters were examinated and choose the suitable parameters. The simulation results showed that feed intake and daily weight gain of high nutrition group were higher than that of low nutrition group. From the simulation results, the dynamic growth model could meet requirement effectively in a certain range.Experiment 4 Lysine requirement model of broilerFour hundred and fifty AA broilers were fed to 21 days old to investigate the effects of dietary lysine levels on growth performance, body composition and blood biochemistry parameters of broilers. Six dietary lysine levels were 0.65%, 0.80%, 0.95%, 1.10%, 1.25% andl.4%o Results showed that: (1) Dietary lysine levels significantly influence the growth and body composition of broilers. (2) Lysine requirement for optimum growth performance and carcass quality is 1.1%~1.25%. (3) Uric acid, TG, LDL, T4, IGF-I concentrations are significantly affected by lysine levels. Plasma UC, TG and LDL levels are increased no matter dietary lysine is deficient or excessive. A lysine requirement model was developed. Quadratic function is better than linear, exponential and other functions.Experiment 5 Effects of lysine levels on the IGF-I mRNA levels in liver and muscle of broilerFour hundred and fifty AA broiler was fed to 21 days old to investigate the effects of dietary lysine levels on IGF-I mRNA level in liver and muscle of broilers by using of RT-PCR molecule technology. Dietary lysine levels were 0.65%,0.80%,0.95%. 1.10 %,1.25% and 1.4% Results showed that dietary lysine levels could affect IGF-I mRNA level. IGF-I mRNA level is the highest when lysine level is 1.1% in liver and 0.95% in musele.It showed that lysine levels affect broiler's growth by adjusting GH way. Lysine requirement model was Y=-4.7559+ 10.9489X+ -5.2348 X2. (R2=0.76)... |
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