| Lueyang chicken is one of the best breeds of Chinese local chicken variety. Now it ismainly used as meat and egg type chicken variety.The experiment takes Nick chicken andDongxiang chicken as reference,and taking growth and development regular and egg qualityas representative character to study Lueyang chicken’s characteristics, which can providescientific basis of breeding in future study.The experiment was divided into five parts:1:The comparison and study on growth and development regular of Lueyangchicken,Dongxiang chicken and Nick chicken from0to20weeks old720chickens of each variety of three varieties(Lueyang chicken,Nick chicken andDongxiang chicken) which were fed with corn-soybean diet and in the same condition and atthe age of0week were selected to determine body weight and phalanx length.Each gender ofthe same variety was taken as one unit which was divided into four repetitions,and eachrepetition had180chickens(♂:♀=1:1).The body weight and phalanx length of each chickenwere determined every week from0to20weeks.Results:The nascent body weight andphalanx length of Lueyang chicken were larger than that of Nick chicken and Dongxiangchicken.Lueyang chicken grew and developed much slower in primary period,and itsdevelopment time was much longer than that of Nick chicken and Dongxiang chicken.Thebody weight and phalanx length of Lueyang chicken were median among three breeds,therewere not significantly different between Lueyang cock and Nick cock(P＞0.05), and the bodyweight of Lueyang chicken was significantly smaller than that of Nick chicken(P＜0.05),butthe body weight and phalanx length of Lueyang chicken were significantly larger than that ofDongxiang chicken at the age of20weeks(P＜0.05).The peak height velocity of body weightand phalanx length of Lueyang cock were9~10weeks and5~6weeks respectively.The peakheight velocity of body weight and phalanx length of Lueyang hen were6~7weeks and5~6weeks respectively.2:Study on analysis and fitting of body weight growth curve and phalanx lengthgrowth curve of Lueyang chicken from0to20weeks oldThe body weight growth curve and phalanx length growth curve of Lueyang chicken acquired from the experiment one was analyzed and fitted with three kinds of nonlinearmodels(Gompertz,Logistic,Bertalanffy).Results:The body weight growth curve and phalanxlength growth curve were appropriately fitted with three models.The Gompertz model had thebest effect on fitting with the body weight growth curves and the Logistic model had the besteffect on fitting with the phalanx length growth curves.The best equations of body weightgrowth curve of Lueyang cock and hen were Y=2272.646e-4.388exp(-0.174t)andY=1715.41e-3.947exp(-0.184t)respectively.The body weight of inflexion were836.06g and631.06g respectively.The weeks of inflexion were8.5w and7.46w respectively,and all of thegoodness-of-fit were0.999.The best equations of body weight growth curve of Lueyang cockand hen were Y=106.807/(1+3.888e-0.276t) and Y=91.271/(1+3.279e-0.291t).The phalanx lengthof inflexion were53.4mm and45.64mm respectively.The weeks of inflexion were4.92w and4.08w respectively,and all of the goodness-of-fit were0.999.3: Study on the growth and development of main tissue and organ and the melaninpigmentation in the skin of Lueyang chicken from6to20weeks oldAfter the body weight and phalanx length were determined in experiment one, eachrepetition of three varieties had16chickens(♂:♀=1:1) which were randomly selected todetermine the weight of thymus,heart,liver,pancreas,spleen,gizzard,glandularstomach,bursal,testicle,ovary and duodenum length,and melanins of Lueyang chicken andDongxiang chicken from6to20weeks old were extracted.Results:1.The growth anddevelopment of main peptic:The growth and development of liver of Lueyang cock slackenedat the age of14weeks,and it still had some growth rate at the age of20weeks.The growth anddevelopment of liver of Lueyang hen slackened at the age of12weeks.The growth anddevelopment of pancreas of Lueyang cock slackened at the age of12weeks.The growth anddevelopment of pancreas of Lueyang hen slackened at the age of16weeks.The growth anddevelopment of gizzard of Lueyang cock and hen slackened at the age of14weeks,and it stillhad some growth rate at the age of20weeks.The growth and develpment of glandularstomach of Lueyang cock slackened at the age of12weeks.The growth and development ofglandular stomach of Lueyang hen slackened at the age of14weeks.The growth anddevelopment of duodenum of Lueyang cock slackened at the age of10weeks.The growth anddevelopment of duodenum of Lueyang hen slackened at the age of12weeks.The peptic indexdecreased as weeks goes by,which was similar to Nick chicken and Dongxiang chicken,andthe organ weight of Lueyang chicken was median among three varieties,it was smaller thanthat of Nick chicken and larger than that of Dongxiang chicken.2.The growth anddevelopment of main immune organs:The spleen index and bursal index of Lueyang chickenindex decreased as weeks goes by,and the thymus index decreased and then increased as weeks goes by,but the weight of immune organs increased and then decreased as weeks goesby.The thymus weight of Lueyang cock increased from6to12weeks old,and then decreasedfrom12weeks old. The thymus weight of Lueyang hen increased from6to14weeks old,andthen decreased from14weeks old. The spleen weight of Lueyang cock increased from6to12weeks old,and then decreased from12to20weeks old. The spleen weight of Lueyang henincreased from6to14weeks old,and then decreased from14to20weeks old.The bursalweight of Lueyang cock increased from6to14weeks old,and then decreased from14weeksold. The bursal weight of Lueyang hen increased from6to14weeks old,and then decreasedfrom14to20weeks old.3.The growth and development of main reproductive organs:Thetesticle index and the testicle weight of three varieties increased as weeks goes by.The growthand development of testicle of Lueyang cock was the slowest among three varieties from6to16weeks old.Despite the growth and development of testicle of Lueyang cock slackened from16weeks to20week old,the testicle weight increased severely as weeks goes by,then thetesticle weight of Lueyang cock was the largest among three varieties.The ovary index ofLueyang hen decreased and then increased as weeks goes by.The growth and development ofovary of Lueyang hen was the slowest among three varieties,and it showed weight increasingtendency at the age of20weeks,but the growth and development of ovary of Nick hen andDongxiang hen showed weight increasing severely at the age of20weeks.4.The growth anddevelopment of main circulatory organs:The growth and development of heart of Lueyangcock slackened at the age of16weeks.The growth and development of heart of Lueyang henslackened at the age of14weeks.The organ weight of Lueyang chicken was median amongthree varieties,it was smaller than that of Nick chicken and larger than that of Dongxiangchicken from6to20weeks old.5.Melanin pigmentation in the skin of Lueyang chicken andDongxiang chicken:The melanin content in the skin of Lueyang cock from6to20weeks oldwere039%,0.34%,0.28%,0.25%,0.22%,0.21%,0.20%,0.9%respectively,and the melaninpigmentation in the skin of Lueyang hen from6to20weeks old were0.43%,0.38%,0.33%,0.29%,0.26%,0.24%,0.23%,0.22%respectively.The ability of melanin pigmentation ofLueyang chicken was superior to that of Dongxiang chicken,but there was not significantlydifferent between breeds and between gender(P＜0.05).The ability of melanin pigmentationof hen was superior to that of cock of the same breed.The melanin content in the skin of cockand hen decreased as weeks goes by.4:The analysis and study on egg quality of Lueyang chicken200eggs of each variety of three varieties(Lueyang chicken,Nick chicken andDongxiang chicken)which were fed in the same condition and at the age of320-325days oldwere collected to determine egg quality,nutritional value and cholesterol content,lecithin content,fatty acid composition of yolk. Results:The egg weight of Lueyang chicken was47.96g,which was the smallest among three varieties.The uniformity of egg shell color ofLueyang chicken was the worst among three varieties.The egg-shape index of Lueyangchicken was0.76,and it was the highest among three varieties.The shell thickness and shellstrength of Lueyang chicken were0.304mm and4.28kg/cm2respectively,which were notsignificantly higher than that of Dongxiang chicken(P＞0.05) while were significantly lowerthan that of Nick chicken(P＜0.05).The albumen height of Lueyang chicken was5.98mm,which was not significantly lower than that of Dongxiang chicken(P＞0.05) whilewere significantly higher than Nick chicken(P＜0.05).The yolk color degree of Lueyangchicken was9.08,which was not significantly different among three varieties(P＞0.05).Thehaugh unit and yolk and albumen ratio(yolk/albumen) of Lueyang chicken were76.21HU and0.75respectively,which were not significantly lower than that of Dongxiang chicken(P＞0.05)while were significantly higher than that of Nick chicken(P＜0.05).The CP content and CFcontent of Lueyang chicken were13.72%and14.04%respectively,which were notsignificantly different among three varieties(P＞0.05).The cholesterol content of yolk ofLueyang chicken was12.53mg/g,which was significantly higher than that of Nick chickenand Dongxiang chicken(P＜0.05).The lecithin concentration of yolk of Lueyang chicken was12.51%,which were not significantly different among three varieties(P＞0.05).The SFAproportion of Lueyang chicken was36.74%,which was significantly higher than that of Nickchicken and Dongxiang chicken(P＜0.05).The UFA proportion of Lueyang chicken was58.97%,which was significantly higher than that of Nick chicken and Dongxiang chicken(P＜0.05).The MUFA proportion of Lueyang chicken was45.22%,which was not significantlylower than that of Dongxiang chicken(P＞0.05) while was significantly lower than that ofNick chicken(P＜0.05).The DUFA proportion of Lueyang chicken was45.22%,which washigher than that of Nick chicken while was lower than that of Dongxiang chicken(P＞0.05).The n-6PUFA and n-3PUFA ratio(n-6/n-3) of Lueyang chicken was10.75,which wassignificantly higher than that of Nick chicken and Dongxiang chicken(P＜0.05).5:Study on effect of physical characteristics of hatching eggs laid by Lueyangchicken on hatchability550hatching eggs were randomly selected within7d from eggs laid by healthy Lueyangchicken whom were naturally mated to hatch.Egg shell color,egg weight, egg shellthickness,egg-shape index,ratio of egg water loss in18d were determined to study therelationship between these items and hatchability.Results:The egg shell color and egg shellthickness had no significant effect on hatchability(P＞0.05);hatchability of small sizeeggs(38.3g~50.0g,77.13%) was the hightest compared to medium eggs(50.1g~55.0g,74.4%) and large size eggs(55.1g~63.6g,73.39%).However the difference did not reach statisticalsignificance(P＞0.05);the ratio of egg water loss in18d had a negative effect on hatchabilitydespite of the fact that it was not significant(P＞0.05);the egg-shape index had a significanteffect on hatchability(P＜0.05),the hatchability of round eggs(0.79~0.85,83.19%) was higherthan that of normal shape eggs(0.74~0.78,74.77%) and narrow shapeeggs(0.68~0.73,69.31%).Conclusion:(1)The growth and development of body weight and phalanx length of Lueyang chickenwere worse than that of Nick chicken,but they were superior to Dongxiang chicken.The peakheight velocity of body weight and phalanx length of Lueyang cock were9~10weeks and5~6weeks respectively.The peak height velocity of body weight and phalanx length ofLueyang hen were6~7weeks and5~6weeks respectively.(2)The Gompertz model had the best effect on fitting with the body weight growthcurves and the Logistic model had the best effect on fitting with the phalanx length growthcurves from0to20weeks old.(3)The growth and development of main tissue and organ had its inherent features.Thepeptic index and circulatory organs index decreased as weeks goes by,which was similar toNick chicken and Dongxiang chicken,and the organ weight of Lueyang chicken was medianamong three varieties,it was smaller than that of Nick chicken and larger than that ofDongxiang chicken.The spleen index and bursal index of Lueyang chicken index decreased asweeks goes by,and the thymus index decreased and then increased and then decreased asweeks goes by,but the weight of immune organs increased and then decreased as weeks goesby.The testicle index and the testicle weight of Lueyang cock increased as weeks goes by.Thegrowth and development of testicle of Lueyang cock was the slowest among three varietiesfrom6to16weeks old.Despite of the growth and development of testicle of Lueyang cockslackened from16weeks to20week old,the testicle weight increased severely as weeks goesby,then the testicle weight of Lueyang cock was the largest among three varieties.The ovaryindex of Lueyang hen decreased and then increased as weeks goes by.The growth anddevelopment of ovary of Lueyang hen was the slowest among three varieties,and it showedweight increasing tendency at the age of20weeks,but the growth and development of ovaryof Nick hen and Dongxiang hen showed weight increasing severely at the age of20weeks.(4)The ability of melanin pigmentation of Lueyang chicken was superior to that ofDongxiang chicken.The ability of melanin pigmentation of hen was superior to that of cock ofthe same breed.The melanin content in the skin of cock and hen decreased as weeks goes by.(5)While the cholesterol content of yolk of Lueyang chicken was significantly higher than that of Dongxiang chicken and Nick chicken,there were no significant differencesbetween Lueyang chicken and Dongxiang chicken in egg quality and the nutritional value ofegg.The inner egg quality and the nutritional value of eggs of Lueyang chicken weresignificantly better than that of Nick chicken,but the egg weight and eggshell quality weresignificantly worse than that of Nick chicken.The fatty acid composition of Lueyang chickenwas the worst among three varieties.(6)The egg shell color of Lueyang chicken had no significant effect on hatchability.Theround egg(0.74~0.85) should be preferably selected for hatching eggs of Lueyang chicken. |
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