The Effects Of Nutrient Levels On Growth And Development,carcass Quality Of Jilin Native Black Chicken

240, one day old Jilin native black chicken were divided into three groups, randomly. Each group included 8 repeats, 10 chicken in each repeat. The high, medium and low nutrients levels diets, formulated according to the yellow feather broiler feeding standard(NY/T 33-2004), were fed to three groups chicken. The experimental periods were divided 0-4 weeks old, 5-8 weeks old, and 9-16 weeks old. The effects of nutrient levels on the growth and development, nutrients metabolism, slaughter performance and meat quality of Jilin native black chicken were measured through the feeding experiment and compare slaughter experiment. The results showed as follow:The ADFI of 0~4 weeks old chicken showed that the low nutrient level group>middle nutrient level group > high nutrient level group(P <0.05), during the 5~8 weeks and 9~16 weeks old, the low nutrient level group> high nutrient level group > middle nutrient level group(P <0.05). ADG and F/G of chicken appeared low nutrient level group>middle and high nutrient level groups(P <0.05). High nutrient level increased ADG(P <0.05), reduced ADFI and F/G, significantly. The growth of the chicken in high nutrient level group fitted Logistic model, however, the growth of the chicken fed middle and low nutrient levels fitted Gompertz model better at the starter stage of the experiment, and fitted Logistic model better during the last stage of experiment.At 4 weeks old, the duodenum and jejunum villus height of the chicken showed that the high nutrient level group > middle, and low nutrient level group(P<0.05); At 8 weeks old, duodenal villus height appeared high and middle nutrient level group> low nutrient level group(P <0.05); At 12 weeks old, duodenum and jejunum villus height of high, middle nutrient level group> low nutrient level(P <0.05), ileum villus height of the high nutrient level group> middle nutrient level group > low nutrient level group(P <0.05).The crypt depth of duodenum and jejunum in 4 weeks old chicken showed that the low nutrient level group> middle nutrient level group> high nutrient level group(P <0.05); At the 8 weeks old, the duodenal crypt depth appeared middle nutrient level group < low nutrient level group(P <0.05), jejunum crypt depth of high nutrient level group was higher than that of low nutrient level group(P <0.05), ileal crypt depth of high nutrient level group was lower than the middle and low nutrient level group(P <0.05); At the 12 weeks old, duodenal crypt depth of high nutrient level group was lower than the middle and low nutrient level group(P <0.05), ileal crypt depth of high and middle nutrient level group was lower than the low nutrient level group(P <0.05).At 4 weeks old, the duodenum muscular thickness of the chicken show the high nutrient level group> middle nutrient level group > low nutrient level group(P <0.05); Jejunal muscular thickness of the high nutrient level group was higher than that of low nutrient level group(P <0.05); At 8 weeks old, the jejunal muscular thickness of chicken appeared the high nutrient level group> middle nutrient level group> low nutrient level group(P <0.05). At the 12 weeks old, the duodenum and ileum muscular thickness of high and middle level group were higher than that in low level group(P<0.05). High nutrients level diet increased the duodenum, jejunum and ileum villus height, and reduced the intestinal crypt depth, intestinal villus height/crypt depth of Jilin black chicken.The response of fat metabolism in different weeks age Jilin black chicken to diet nutrient level were similar, the low nutrient level group was higher than that in the high nutrient level group(P<0.05). There was no significant difference between the middle nutrient level and high nutrient level. At the 8 weeks old, the metabolic rate of dry matter is sensitive to dietary nutrient levels, it appeared the low nutrient level group > middle nutrient level group> high nutrient level group(P <0.05); There no significantly difference between the low and middle nutrient level group, but both of the two groups were higher than the high nutrient level group(P <0.05) at the 4 weeks old; At 12 weeks old dry matter metabolic rate was low nutrient level group > middle and high nutrient level group(P <0.05).The significant effects of diet nutrient level on the protein metabolic rate were not found at the 4 weeks old, however, the protein metabolic rate of low and middle nutrient level group were higher than the high nutrient level group(P<0.05),and the low nutrient level group was higher than the middle and high nutrient level group at the 12 weeks old(P<0.05). There no significant effects of diet nutrient level on the energy metabolism。At the 4 weeks old, the level of triglycerides, cholesterol,uric acid and alkaline phosphatase concentration in Middle nutrient level group was highest(P<0.05). At the 8 weeks old, the uric acid, urea nitrogen and alkaline phosphatase concentration appeared middle nutrient level group > Low nutrient level group > high nutrient level group. At 12 weeks old, alkaline phosphatase concentration in the middle nutrient level group was the highest(P <0.05).There no significant effects of diet nutrient level on the slaughter rate, whole net carcass rate, breast muscle rate and leg muscle rate in the Jilin native black chicken(P > 0.05). At the 16 weeks old, the half net carcass rate in middle nutrient level group were lower than that in high nutrient level group(P <0.05). With the increasing of diet nutrient level, muscle fiber diameter increased, however, the muscle fiber density is not sensitive to the diet nutrient levels(P > 0.05). There no significant effects of diet nutrient level on the muscle pH, water holding capacity and water loss rate.Pectoral muscle protein content of the chicken in high nutrient level group got the maximum at 14 weeks old(P<0.05),however, the middle level group got the maximum at 15 weeks old and the low level group got the maximum at 14 weeks old.The flavor amino acid content of pectoral muscle of high nutrient level group reached maximum at the 14 weeks old(P < 0.05), however, the middle nutrient level group got the maximum at the 13 weeks old(P <0.05); The flavor amino acid content of leg muscle in high level group was highest at the 15 weeks old(P <0.05), but the middle level group got the maximum at the 13 weeks old(P <0.05), and the low nutrient level group reached maximum at the 12 weeks old(P < 0.05).