Effects Of Dietary Different Crude Protein Levels On Production Performance And Breed Performance Of Jining Bairi Chicken

A series of experiments were conducted to study the effects of dietary crude protein levels on production performance, egg quality, serum biochemical parameters, breed performance and newborn chicks of Jining Bairi Chicken and to establish factorial models of crude protein requirement. Moreover, through this was to define the protein requirement, and to provide theoretical and practical bases of Jining Bairi Chicken’s feeding standard.A total of 525 40-week-old Jining Bairi Chickens were randomly allocated into 5 treatments of 5 replications of 21 chickens. The pre-experiment period lasted for 7 d, and the experiment lasted for 56 d. A single factor design was used to study the effects of dietary crude protein levels on Jining Bairi Chicken. The crude protein levels of the experimental diets were 13%, 14%, 15%, 16%, 17%, and other nutritional composition keep similarly.The experiment contains three parts: ①Effects of dietary crude protein levels on production performance, egg quality and serum biochemical parameters of Jining Bairi Chicken. ②Effects of dietary crude protein levels on breed performance of Jining Bairi Chicken. ③Effects of dietary crude protein levels on newborn chicks of Jining Bairi Chicken. Results showed that:Dietary crude protein levels had effects on egg number, laying rate, egg weight, daily egg mass and daily qualified egg mass, daily crude protein intake and ratio of feed to egg(P<0.05). Daily feed intake, body weight, metabolic body weight, daily gain, unqualified egg rate and survival rate was not significantly affected by dietary crude protein levels(P>0.05). With the increasing of crude protein, daily crude protein intake increased linearly and produced a consistent trend as crude protein. With crude protein levels from 13% to 16%, egg weight showed an increase linearly. The maximum production performance was highest in 16% crude protein group.Dietary crude protein levels had affected egg weight from 41 to 48 weeks and eggshell hardness at the age of 48 weeks(P<0.05). With crude protein levels from 13% to 16%, egg weight showed an increase linearly. With the increasing of crude protein, eggshell hardness increased linearly. The maximum eggshell hardness was highest in 17% crude protein group. Albumen height, percentage yolk, Haugh unit, yolk weight, egg-shape index, egg shell weight, egg shell thickness and yolk protein ratio were not significantly affected by dietary crude protein levels from 41 to 48 weeks(P>0.05).Dietary crude protein levels effected serum total protein, serum albumin and serum uric acid(P<0.05), but not serum urea at the age of 44 weeks(P>0.05). At the 48 weeks age, serum biochemical parameters were hardly significantly affected by dietary crude protein levels but serum urea(P<0.05).Dietary crude protein levels had affected total egg number and hatchable egg number hatched chick number(P<0.05). Hatchable egg rate, fertilization rate and hatchability were not significantly affected by dietary crude protein levels from 41 to 48 weeks(P>0.05).Breed dietary crude protein levels had no effects except heart weight(P<0.05) on newborn chicks at the age of 44 weeks, but effected birth weight and liver weight of newborn chicks(P<0.05) at the age of 48 weeks. Serum biochemical parameters on newborn chicks were hardly significantly affected by breed dietary crude protein levels but serum uric acid(P<0.05).A series of comparative experiments were conducted to study the effects of dietary crude protein levels on production performance, egg quality, serum biochemical parameters, breed performance and newborn chicks of Jining Bairi Chicken. Average dietary crude protein intake(ADCPI) and average daily gain(ADG) were regarded as dependent variable(Y) and independent variable(X) respectively, then linear regression were made, the result as follows:ADCPI=0.2680ADG+0.2711ADEM+3.2993BW0.75ADCPI=0.3347ADG+0.2784ADQEM+3.3684BW0.75The better crude protein level for the best production performance of Jining Bairi Chicken is 15.49%.The better dietary crude protein level for the best breed performance of Jining Bairi Chicken is 14.81%.