Effect Of Feed Restriction And Photoperiod On Growth And Development,blood Biochemical Parameters And Leptin Receptor Expression In Pullets

A feeding study was performed to investigate effect of feed restriction andphotoperiod on growth and development, digestibility of nutrients,intestinalstructure,Blood Biochemical Indices,liver leptin receptor expression in growing chicken.the mechanism of their influence on growing chicken was discussed. the theoretical basisfor the rational application of restricted feeding and photoperiod in laying hens wasProvided.Three hundred twenty10-week old healthy commercial hens were selected andused2*2two factors experiment design,each treatment was divided into four replicatescomprising twenty growing chicken each. Chicken were housed in a8h light/16h darkcycle (LD8:16) prior to10weeks of age while those with ad libitum feeding.Record dailyfeed rate, temperature and humidity in the henhouse.(1)Feed restriction has a significant difference of the effect on weight of14weeks oldand fat weight of18weeks old (p<0.05). The weight of14weeks old, At8L:16D and12L:12D photoperiod, fat weight of18weeks old, the cafeteria feeding group higher thanthe feed restriction group. The illumination didn’t influence (p>0.05).the feed consumption,weight and fat weight of the14and18weeks old layers, no interactions were observedbetween feed restriction and photoperiod.(2)The photoperiod has no a significant difference of the effect on metabolic rate ofdry matter(p<0.05), the metabolic rate of dry matter of8L:16D group significantly higherthan12L:12D photoperiod. Feed restriction has no a significant difference of the effect onmetabolic rate of dry matter. The photoperiod has no a significant difference of the effecton metabolic rate of crude protein(p>0.05). Feed restriction has a significant difference ofthe effect on metabolic rate of crude protein(p<0.05),At8L:16D and12L:12D photoperiod,the metabolic rate of crude protein of feed restriction group higher than the cafeteriafeeding group, but the photoperiod has no a significant difference of the effect onmetabolic rate of crude protein(p>0.05). the photoperiod and the level of feed restrictionhave no a significant difference of the effect on metabolic rate of calcium andphosphorus(p>0.05), no interactions were observed between the photoperiod and feedrestriction.(3)The interaction between the photoperiod and feed restriction have a significant difference of the effect on metatarsus length of14weeks old, feed restriction have asignificant difference of the effect on keel length of14weeks old.14weeks old layer,under the condition of8L:16D and12L:12D photoperiod, the metatarsus length ofcafeteria feeding group higher than the feed restriction group. The photoperiod has asignificant difference of the effect on the Pubic space of18weeks old layer(p<0.01), underthe condition of feed restriction and cafeteria feeding, The illumination group of8hourssignificant higher than12L:12D photoperiod Feed restriction has no a significantdifference of the effect on the Pubic space of18weeks old layer(p>0.05), The photoperiodhas a significant difference of the effect on the length and thickness of comb of14weeksold layer. Under the condition of feed restriction and cafeteria feeding, the length andthickness of comb of8L:16D illumination group significantly higher than12L:12Dphotoperiod group. The photoperiod has a significant difference of the effect on the lengthof comb of14weeks old layer(p<0.01).(4)Feed restriction has a significant difference of the effect on the length of duodenalvillus of14weeks old layer(p<0.01), The interaction between the photoperiod and feedrestriction have a significant difference of the effect on the length of duodenal villus of14weeks old layer(p<0.05), the photoperiod has a significant difference of the effect on thelength of jejunum villus of14weeks old layer(p<0.05), under the condition of feedrestriction and cafeteria feeding, the12L:12D photoperiod group significant higher thanthe8L:16D photoperiod. the photoperiod has a significant difference of the effect on thelength of duodenal villus of18weeks old layer(p<0.01）, under the condition of feedrestriction and cafeteria feeding, the illumination group of12hours significant higher than8hours. The interaction between the photoperiod and feed restriction have a significantdifference of the effect on the length of duodenal villus and jejunum villus (p<0.05). Feedrestriction has a significant difference of the effect on the length of ileum villus of18weeks old layer(p<0.01), under the condition of8L:16D and12L:12D photoperiod, thelength of ileum villus of the feed restriction group significant higher than the cafeteriafeeding group, and the interaction between the photoperiod and feed restriction have asignificant difference of the effect on the length of ileum villus of18weeks oldlayer(p<0.01).(5) At14wk，the depth of intestinal crypt8L:16D photoperiod group is deeper than12L:12D significantly,no matter pullets were restricted feed intake or not.feed restrictionhad significant effects on the depth of duodenum’s intestinal crypt(P<0.05).In8L:16Dphotoperiod,the depth of duodenum’s intestinal crypt of feed-restriction group was deeperthan ad libitum group significantly.At14wk,feed restriction had a very significant effect onthe depth of ileum’s intestinal crypt(P<0.01),effects of feed restriction on the depth ofileum’s intestinal crypt were significant(P<0.05).At8L:16D photoperiod,the depth ofjejunum’s intestinal crypt of feed-restriction group was deeper than ad libitum group significantly.Feed restriction effected the depth of ileum’s intestinal cryptsignificantly(P<0.05).In both8L:16D and12L:12D photoperiod,the depth of ileum’sintestinal crypt of feed-restriction group were deeper than ad libitum group significantly.At18wk, effects of photoperiod on the depth of duodenum’s intestinal crypt weresignificant(P<0.01).Restricted feed intake or not,the depth of duodenum’s intestinal cryptof8L:16D photoperiod group was deeper than12L:12D.feed restriction effccted the depthof intestinal crypt of jejunum significant(P<0.05).In12L:12D photoperiod,the depth ofjejunum’s intestinal crypt of feed-restrition group was deeper compared with ad libitumgroup.At18w,the pullet’s interaction of photoperiod and feed restrition on jejunum villuslength was significant(P<0.01).feed restristion effected the depth of intestinal crypt ofjejunum villus length significantly(P<0.05),In both8L:16D and12L:12D photoperiod,thedepth of intestinal crypt of ileum that were provided with ad libitum were deeper thanfeed-restrition group.Photoperiod effected the intestinal villus length significantly(P<0.05).(6) For chickens of14weeks and18weeks of age, the effect of length ofillumination time and limited feeding on the plasma glucose level and lipid level was notsignificant (P>0.05); The level of plasma lipids of limited feeding group were higher thanthe ad libitum group; The level of plasma glucose of limited feeding group were lower thanthe ad libitum group; Both levels of plasma lipids and blood glucose of the chicken at18week were higher than the14week(P>0.05), there is no interaction between photoperiodand limited feeding utility.(7) Photoperiod and limited feeding have a significant effect on expression levelofthe leptin receptor gene in liver from chickens of14week of age (P <0.05); For8L:16Dphotoperiod group, the expression level of ad libitum group was0.17%higher than limitedfeeding group; For12L:12D photoperiod groups, the expression of ad libitum group was0.45%higher than limited feeding group. The leptin receptor gene expression level of12L:12D photoperiod group was0.21%higher than8hours on the limited feeding group.The leptin receptor gene expression level of12hours of light treatment group was0.39%higher than8L:16D photoperiod group. The lengths of illumination time have a significanteffect on the expression levels of leptin receptor gene in the liver on growing chicken of18weeks of age (P <0.05).(8) Photoperiod and restricted feeding on the rearing of laying hens age at first egg, open eggweight, egg production sound effects weight difference was not significant (P>0.05), photoperiod andrestricted feeding does not exist between the interaction effect.