Study On The Relationship Of Digestive Organs Growth And Body Weight Change In P1 Gushi Chicks

Body weight puting-up and development of degestion system of Pt generation Gushi chicken raised in large scale were surveyed by gross anatomy and tissue slice technique and Leica Qwin image analysis system,in order to access to more knowledge of the development characteristics of the bird,and to offer more material concerned with the selection and breeding of the fowl for reference.1.The results of the Logistic regression analysis of weight putting up and weight of dcgestivc organs show a conformance to the expected model.The male chicken put up weight gradually during 0～6.25 weeks,and then grow rapidly until 16.53 weeks,and,at the age of 11.39 weeks the growth rate slows down,and from then putting up of weight turns into a ralatively slow period.In the female chicken,these periods of development of weight took place at the age of 0～5.62 weeks,5.62～15.94 weeks and 10.78 weeks respectiely.2.The development of digestive organs also conform to Logistic model,with fitting dgrce between 0.97829～0.99802.The order of degestive organs entering the rapid growth period follows this sequence:preventriculus,esophagus,gizzard,craw, liver and pancrea,rectum,small intestine,caecum,with the esophagus develops to the mature level first,and preventriculus along with gizzard followed closely behind, and the next is degestion gland.The intestines is full developed at the last.All the degestive organs would become full developed prior to the maximum weight reached.3.The weight of digestive organ reaches 50%of the value of 20 weeks chiken around the age of 8 weeks,and higher than 90%of the value are reached around 16 weeks of age,by then,the development of digestive organs are closing to completeness.The digestive organ index(DOI)shows a declining trend,which indicates that the digestive organs grow slower than the putting up of body weight. DOI decreases from 17%during the first week of age to 9%in 20 weeks of age. The digestive organ index of female chicken is higher of that of males.4.Lenths of digestive tracts extends with age.The prolonging of digestive ducts is insynchronous,with the esophagus,ileum,and caecum growing faster and duodenum along with jejunum growing slower,while the preventriculus and rectum grow in a relatively steady manner.The digestive ducts are usually reaching the maxium length by the age of 16 weeks,with the lengths of every parts following this sequence:jejunum,duodenum,caecum,esophagus,ileum,rectum and preventriculus.5.logarithm and power regression equation can precisely indicates the ralationship between changes of digestive ducts length and body weight,and when combined with the data from the limit Logistic regression,the length of every part of digestive ducts can be calculated.The length limits of small intestine in male and female chichen are 158.93cm and 139.27cm,respectively.And the length limits of total digestive ducts in male and female chicken are 226.38cm and 202.42cm, respectively.6.The perimeter of every parts of digestive ducts increases gradually with age, and the growth slowed down significantly at the age of 16 weeks.The perimeter of different parts of digestive ducts show great diversity,with a higher value in the male chicken than females.The normally larger ducts are not necessarily always be lager than the other ducts during different periods of degestive ducts development,because of the insynchronously development of diffefent parts of the ducts.In terms of perimeter,the largest part of digestive duct is cervical eoesophagus,and the smallest part is ileum.The diameter decreases gradually from the upstream down to the downstream of small intestine.7.The number of the preventriculus papillae doesn't changes in a orderly way, with an average 55.8 papillae in males and 57.4 in females.The gizzard of males is thicker than females,with the dorso-muscle thicker than the ventro part.The length of small intestine villi increases with age,with longer ones in males.The villi is branched and centrol chyle vessel is not obviously seen.The depth of Intestinal gland crypts increases more obviously during the first 4 weeks than any periods afterwards,when the increasement of the crypts gets steady.During any period of the growth of the chicken,the crypts of dudoneum is deeper than jejunum,and jejunum crypts deeper than ileum.The density of intestinal gland decreases with age, with an average of 6 to 7 crypts per 400μm in length.