Effects Of Supplement Of Youlian Peptide On Performance And Production Quality In Fowl

To determine the suitable supplement of Youlian peptide in the diets of white feather broiler, yellow feather broiler and layer chicken, and analyze the effect mechanism of increasing performance of broilers, three feed experiments were carried out respectively. Different levels Youli'an peptide was added into diets of broilers. The performance of broilers were determined using the performance index (feed intake, body weight, survival rate, laying rate, feed conversion rate) and the change rule of the levels of the neuropeptide Y (NPY), growing hormone(GH) and insulin-like growth factor I(IGF-I) in broilers blood were detected. The production quality were measured and appraised using the index of naked body, dressed percentage, percentage of half-eviscerated yield, percentage of eviscerated yield, percentage of breast muscle, percentage of leg muscle in white feather and yellow feather broiler, and weight and specific density of egg, egg shape-index, shell thickness, haugh unit, percentage of albumen, percentage of yolk, percentage of shell in layer chicken.In the feed experiment of white feather broilers, 270 healthy one day age Arobor Acres broilers were randomly divided into 6 groups( 3 duplications in each group ), and the corn-soybean basal diet with 0 ppm, 20 ppm,40 ppm,60 ppm,80 ppm,100 ppmYoulian peptide were supplemented to the group respectively. Water and feed were available ad libitum throughout the experiment stage, the broilers were raised according to the corresponding nutrition need. The body weight and surplus forage were measured on the day 14, 28, 42, 56, 63 in the early morning respectively( stop feeding before weighting), and the feed intake of each group were calculated . After weighting, 5 mL blood were collected via wing vein from 5 broilers of each duplication and centrifuged 3000 rpm for 10 min,blood serum were stored at -20℃for later assay. On 56 day age, 3 broilers which approached average body weight from each duplication were slaughtered, the dressed percentage, percentage of half-eviscerated yield, percentage of eviscerated yield, percentage of breast muscle and leg muscle were measured and calculated. The data of serum index and growth performance were analyzed by correlation analysis methods. The results showed that the survival rate of broilers in 80 ppm and 100 ppm Youlian peptide supplement group were lower than that of other groups(P<0.05). Throughout the experimental stage, daily gain of 40 ppm and 60 ppm supplement group was higher than that of other groups, but gain feed ratio was lower(P<0.05). Compared with the control group, daily gain of 60 ppm Youlian peptide supplement group increased 12.96% gain feed ratio decreased 3.72%. Along with the increasing of Youlian peptide supplement, the increasing of daily gain was significant, Comparing to control group during day 1-14, when the Youlian peptide supplementation was up to 100 ppm, daily gain increased 7.74%, but during the whole experiment stage, average daily gain had no obvious change, on the contrary rate, the gain feed ratio increased 1.06%, survival rate decreased 6.95%. The levels of IGF-I increased continually, but the levels of NPY and GH in serum of experiment groups increased before 28 day age and decreased after 42 day age. Between the groups, The levels of serum NPY increased along with the increasing of addition level of Youlian peptide in feed(P<0.05), GH and IGF-I of 40 ppm and 60 ppmYoulian peptide supplement group were higher than that of other groups(P<0.05). There is a significant positive correlation between the daily gain and the levels of serum GH and IGF-I(P<0.01), and a significant negative correlated between the gain feed ratio and the levels of serum IGF-Ⅰ(P<0.01).In the feed experiment of yellow feather broilers, 450 healthy one day age north third cockerels poults were divided into 6 groups(3 duplications in each group), the breed manager and experiment design were the same as described in the feed experiment of white feather broiler. But blood serum samples were collected from 20 broilers of each duplication for later assay and 5 cocks which approach average body weight from each duplication were slaughtered on day 63. The results showed that survival rate of 80 ppm and 100 ppm Youlian peptide supplement group were lower than other group(sP<0.05). in whole experimental stage, the daily gain of broilers of 40 ppm and 60 ppm Youli'an peptide supplement group was higher than that of other groups, but gain feed ratio was lower(P<0.05). Compared with control group, daily gain of 60 ppmYoulian peptide supplement group increased 13.98% and gain feed ratio decreased 3.43%. Along with the increasing of Youlian peptide supplementation, the daily gain was significant increased. Comparing to the control group during 1-14 day stage, when the Youlian peptide supplement level added up to 100 ppm, daily gain increased 7.74%, but during the whole experiment stage, daily gain had no obvious change, on the contrary , gain feed ratio increased 2.45% and survival rate decreased 6.95%. The levels of NPY and GH in serum of experiment groups increased before 28 days age and decreased after 42 day age and the levels of IGF-I continuously increased. For each group, the level of the serum NPY increased along with the increasing of addition level of Youlian peptide in feed(P<0.05), the levels of GH and IGF-I in serum of 40 ppm and 60 ppmYoulian peptide supplement group were higher than that of other groups(P<0.05). There is a significance correlation between the daily gain and the levels of serum GH and IGF-I(P<0.01), and a significance negative correlated between the gain feed ratio and the levels of serum IGF-I(P<0.01), too.In the feed experiment of layer chicken, 1800 healthy one day age Hy-line layer chicken were divided into 6 groups(3 duplications in each group), and the corn-soybean basal diet with 0, 30,45,60,75,90 ppm Youlian peptide were supplemented to the group respectively. Water and feed were available ad libitum, using stage-wise brooding mode during 0～17 week. The chicken were shifted to layer house at 18 week age and raised according to the corresponding nutrition need. The body weight and surplus forage of 28, 42, 84, 119 day age were measured in the early morning respectively (stop feeding before weighting), and calculated the intake feed of each group. Blood samples were collected after weighting, serum were prepared and stored at -20℃for later assay. After putting in cage, the day of the first egg produced, egg-laying rate at 5% and 50% by layer chicken from each duplication were recorded respectively. We analyzed and tested the reject rate, feed conversion rate, egg-laying rate and egg quality between 27 and 32 week.The results showed that the growth velocity and brooding rate of layer chicken at the growing stage increased with the increasing level of Youlian peptide supplement in feed(P<0.05), the same trends were display in grown up rate, but at the late growing stage, grown up rate of 75 ppm Youlian peptide supplement group was lower than that of control group and other groups(P<0.05). There is a significant positive correlation between the Growth velocity , laying rate of layer chicken and levels of NPY in blood(P<0.05). With the increasing of Youlian peptide supplement, the schedule of produce eggs of experiment layer chicken were in advanced(P<0.05), laying rate increased with the increasing of Youlian peptide supplement during the analysis stage, egg shell increased significantly(P<0.05), but average egg weight decreased(P<0.05).These results suggest that adding Youlian peptide in feed of broilers can increase daily gain and laying rate, but when the supplementation is too high, the survival rate will be decreased significantly. According the economic returns analysis, for the common raising mode with corn - soybean basal diets with the supplementation of Youlian peptide at 60～80 ppm in broiler diets, 75～90 ppm in layer chicken brooding diets, 60～75 ppm in late growing stage diets respectively were suitable.