【作者】 杨军；

【导师】 张克英；

【作者基本信息】 四川农业大学 ， 动物营养与饲料科学， 2022， 博士

【摘要】 肉种鸡饲养周期延长导致的生产性能、种蛋质量和子代生产性能下降与卵巢氧化应激相关。同时,种蛋储存条件是影响种蛋质量的关键因素之一,延长种蛋储存时间降低了种蛋孵化性能、雏鸡质量和子代生产性能,这可能是胚胎在种蛋储存过程中发生了氧化应激反应。维生素E(VE)在缓解机体氧化损伤的过程中发挥重要作用。本文通过3个试验,以“种鸡—种蛋—子代肉鸡”为主线,系统研究了饲粮VE水平对种鸡产蛋性能、种蛋质量和子代生产性能的影响,并进一步探讨了肉种鸡饲粮添加VE延长种蛋储存时间的营养效应及可能机制。试验1饲粮维生素E水平对肉种鸡产蛋性能和抗氧化能力的影响本试验包括试验1-1和1-2。试验1-1选用71 wk Ross 308肉种母鸡512只,试验期13 wk;共2个处理(饲粮VE水平为6和100 mg/kg),每个处理8个重复,每个重复32只。结果显示,饲粮VE水平对产蛋性能无影响(P>0.05)。提高饲粮VE水平提高了卵巢T-SOD活性和T-AOC(P<0.05),降低了卵巢MDA含量(P<0.05)。试验1-2选用75 wk Ross 308肉种母鸡576只,试验期12 wk;共3个处理(饲粮VE水平为100、200和400 mg/kg),每个处理6个重复,每个重复32只。结果显示,饲粮VE水平对产蛋性能无影响(P>0.05)。400 mg/kg VE组血清T-AOC高于100和200 mg/kg VE组(P<0.05),200 mg/kg VE组卵巢MDA含量低于100 mg/kg VE组(P<0.05)。综上可知,以产蛋性能为评价标识,NRC(1994)推荐的肉种鸡饲粮VE水平(6 mg/kg)满足70 wk后老龄母鸡需要;提高饲粮VE水平(100、200和400 mg/kg)对延长饲养周期(>70 wk)的肉种鸡产蛋性能无影响。肉种鸡饲粮VE水平提高至100 mg/kg可提高种鸡卵巢抗氧化能力。试验2肉种鸡饲粮维生素E水平和种蛋储存时间对种蛋质量的影响及机制研究本试验包括试验2-1和2-2。试验2-1采用2×2因子试验设计,主效应包括种鸡饲粮VE水平(6和100 mg/kg)和种蛋储存时间(0和14 d)。试验共4个处理,每个处理6个重复,种蛋收集时间为试验1-1肉种鸡饲养第8、10和12 wk。种蛋储存温度分别为8 wk:22-24℃;10 wk储存1-7和8-14 d:22-24℃和16-18℃;12 wk:16-18℃。结果显示,延长种蛋储存时间降低了种蛋常规蛋品质和蛋黄T-AOC(P<0.05);降低了入孵蛋和受精蛋孵化率、雏鸡重量、健雏率和入舍鸡产健雏数(P<0.05);降低了10和12 wk雏鸡大脑MDA含量和T-AOC(P<0.05);提高了种蛋储存失重率、孵化1-7和15-21.5 d胚胎死亡率(P<0.05);提高了8 wk雏鸡血清、大脑和卵黄囊MDA含量和T-AOC(P<0.05);提高了10 wk雏鸡血清MDA含量和T-AOC(P<0.05);提高了12 wk雏鸡血清T-AOC和卵黄囊MDA含量(P<0.05)。提高种鸡饲粮VE水平提高了蛋黄α-生育酚含量和T-AOC(P<0.05);提高了入孵蛋和受精蛋孵化率(P<0.05);提高了雏鸡血清和卵黄囊T-SOD活性和T-AOC(P<0.05);降低了孵化1-7 d胚胎死亡率(P<0.05);降低了蛋黄以及雏鸡血清、大脑和卵黄囊MDA含量(P<0.05)。相对于未储存种蛋,种蛋在储存14 d条件下,提高种鸡饲粮VE水平表现出更强的改善种蛋孵化性能和雏鸡抗氧化能力的效应。进一步分析发现,延长种蛋储存时间降低了孵化3 d和7 d胚胎重量(P<0.05);提高了孵化7 d胚胎T-AOC(P<0.05);提高了孵化3 d和7 d胚胎ROS含量(P<0.05);提高了孵化3 d和7 d胚胎以及雏鸡大脑和肝脏细胞凋亡率(P<0.05)。提高种鸡饲粮VE水平降低了孵化7 d胚胎MDA含量(P<0.05);降低了雏鸡肝脏和大脑ROS含量(P<0.05);降低了孵化3 d和7 d胚胎以及雏鸡大脑细胞凋亡率(P<0.05)。提高种鸡饲粮VE水平表现出更强的降低储存种蛋孵化7 d胚胎MDA含量和雏鸡肝脏细胞凋亡率的正向效应。胚胎转录组分析结果显示,种鸡饲粮VE水平和种蛋储存时间对胚胎死亡率的影响与氧化应激、细胞凋亡、细胞增殖分化和胚胎发育相关通路有关。功能基因集和m RNA定量结果显示,种鸡饲粮添加VE和种蛋储存时间单独或交互地调控氧化应激、细胞凋亡、细胞增殖分化和胚胎发育相关基因表达,包括Ogg1、Gst、Sod3、Selenop1、Mt3、Pon2、Nrf2、Col6a、G0s2、Wnt11、Bok、Casp3、Bax、Bcl2和Hspb8。试验2-2种蛋均来自试验1-2,包括9 wk未储存和12 wk储存(储存14 d:温度16-18℃)种蛋,均包括3个处理(种鸡饲粮VE水平:100、200和400mg/kg)。结果显示,随着饲粮VE水平提高,未储存和储存种蛋蛋黄α-生育酚含量和T-AOC提高,MDA含量降低(P<0.05);提高饲粮VE水平提高了储存种蛋入孵蛋和受精蛋孵化率、入舍鸡产健雏数以及雏鸡组织T-AOC(P<0.05);降低了储存种蛋孵化1-7 d胚胎死亡率、孵化7 d胚胎以及雏鸡MDA含量(P<0.05)。综上可知,延长种蛋储存时间(14 vs.0 d)能够抑制胚胎发育,降低种蛋孵化性能以及蛋黄、胚胎和雏鸡抗氧化能力;提高种鸡饲粮VE水平能够缓解种蛋储存诱导的孵化性能下降。种鸡饲粮VE水平和种蛋储存时间对孵化性能的影响涉及氧化应激、细胞凋亡、细胞增殖分化和胚胎发育等显著性富集通路。氧化应激相关基因Ogg1、Gst、Sod3、Selenop1、Mt3、Pon2和Nrf2以及细胞凋亡和增殖相关基因Col6a、G0s2、Wnt11、Bok、Casp3、Bax、Bcl2和Hspb8可能是调控种鸡饲粮VE缓解种蛋储存诱导的胚胎氧化应激以及孵化性能下降的关键基因。以未储存种蛋孵化性能为评价标识,NRC(1994)推荐水平(6 mg/kg)满足需要;在种蛋储存时间延长的条件下,肉种鸡饲粮VE添加水平至少应达到200 mg/kg。试验3肉种鸡饲粮维生素E水平和种蛋储存时间对子代生产性能和抗氧化能力的影响本试验包括试验3-1、3-2、3-3、3-4和3-5。试验3-1、3-2和3-3种蛋均来自试验1-1。试验3-1采用2×2因子试验设计,主效应包括种鸡饲粮VE水平(6和100 mg/kg)和种蛋储存时间(0和14 d),共4个处理,每个处理8个重复,子代饲粮VE水平为100 mg/kg。试验1-1第10 wk种蛋(储存0 d)和8 wk种蛋(储存14 d;温度22-24℃)孵化后,将各处理组1 d雏鸡混合,从中随机选择104只分配到8个重复,每个重复13只(公5,母8)。在21 d称重后,将处理组内各重复内公母分开,调整为公母各4个重复。结果显示,延长种蛋储存时间降低了子代肉鸡21和42 d体重以及8-21 d、1-21 d和22-42 d体增重和采食量(P<0.05);降低了子代公鸡21和42 d肝脏T-SOD活性(P<0.05);提高了1-7 d料重比(P<0.05);提高了子代母鸡7 d肝脏和血清MDA含量(P<0.05)。提高种鸡饲粮VE水平降低了1-7 d料重比(P<0.05);提高了子代公鸡21 d血清T-SOD活性(P<0.05)。延长种蛋储存时间降低了公鸡42 d体重和22-42 d体增重(P<0.05),对母鸡无影响(P>0.05)。提高种鸡饲粮VE水平降低了储存14 d种蛋孵化子代母鸡7 d血清MDA含量和孵化子代肉鸡42 d血清MDA含量,对储存0 d种蛋孵化子代肉鸡无影响(P<0.05)。试验3-2采用2×2因子试验设计,主效应包括种鸡饲粮VE水平(6和100 mg/kg)和种蛋储存时间(0和14 d),共4个处理,每个处理8个重复,子代饲粮VE水平为100 mg/kg。试验1-1第12 wk种蛋(储存0 d)和10 wk种蛋(储存14 d;储存1-7 d和8-14 d温度分别为22-24℃和16-18℃)孵化后,将各处理组1 d雏鸡混合,从中随机选择128只分配到8个重复,每个重复16只(公7,母9)。在7 d称重后,将处理组内各重复内公母分开,调整为公母各4个重复。结果显示,延长种蛋储存时间降低了子代肉鸡7和42 d体重以及1-7 d体增重和采食量(P<0.05);提高了子代母鸡7 d血清、子代肉鸡21 d血清和子代肉鸡42 d肝脏MDA含量(P<0.05)。提高种鸡饲粮VE水平降低了子代公鸡7 d血清MDA含量(P<0.05),提高了子代肉鸡42 d血清T-SOD活性(P<0.05)。提高种鸡饲粮VE水平提高了储存14 d种蛋孵化子代公鸡7 d血清T-SOD活性(P<0.05),降低了储存14 d种蛋孵化子代母鸡7 d肝脏MDA含量(P<0.05),对储存0 d种蛋孵化子代无影响(P>0.05)。试验3-3采用2×2因子试验设计,主效应包括种鸡饲粮VE水平(6和100 mg/kg)和种蛋储存时间(0和14 d),共4个处理,每个处理8个重复,子代饲粮VE水平为100 mg/kg。试验1-1第14 wk种蛋(储存0 d)和12 wk种蛋(储存14 d;温度16-18℃)孵化后,将各处理组1 d雏鸡混合,从中随机选择160只分配到8个重复(公母各4个重复),每个重复20只。结果显示,延长种蛋储存时间降低了子代肉鸡42 d体重、22-42 d和1-42 d体增重以及8-21 d、22-42 d和1-42 d采食量(P<0.05);提高了子代肉鸡21 d血清以及42 d血清和肝脏MDA含量(P<0.05)。提高种鸡饲粮VE水平降低了子代肉鸡7 d血清MDA含量(P<0.05)。提高种鸡饲粮VE添加水平降低了储存14 d种蛋孵化子代肉鸡21 d血清MDA含量(P<0.05),对储存0 d种蛋孵化子代肉鸡无影响(P>0.05)。试验3-4和3-5种蛋均来自试验1-2。试验3-4采用3×2因子试验设计,包括3个种鸡饲粮VE水平(100、200和400 mg/kg)和2个子代饲粮VE水平(0和35 mg/kg),共6个处理,每个处理6个重复,每个重复20只(公母各半)。试验1-2第9 wk未储存种蛋孵化后,将各母源处理组1 d雏鸡混合后分组,试验共42 d。结果显示,种鸡饲粮VE水平(100、200和400 mg/kg)和子代饲粮VE水平(0和35 mg/kg)对子代生产性能无影响(P>0.05)。试验3-5采用单因子试验设计。试验1-2第12 wk储存种蛋孵化后,将各母源处理组1 d雏鸡混合后分组。试验共3个处理(种鸡饲粮VE水平:100、200和400 mg/kg),每个处理5个重复,每个重复26只(公12;母14)。子代饲粮均不添加VE。结果显示,提高种鸡饲粮VE水平提高了子代肉鸡21、28、35和42 d体重以及15-21和1-42 d体增重(P<0.05);提高了子代肉鸡血清和肝脏T-SOD活性以及肝脏T-AOC(P<0.05);降低了子代肉鸡8-14 d和15-21 d料重比(P<0.05)以及子代肉鸡肝脏MDA含量(P<0.05)。综上可知,延长种蛋储存时间降低子代肉鸡生产性能和抗氧化能力,种蛋储存温度越高,影响越大。当子代饲粮VE添加水平为100 mg/kg时,提高种鸡饲粮VE水平(100 vs.6 mg/kg)有利于雏鸡早期生长发育,能部分缓解种蛋储存时间诱导的子代肉鸡抗氧化能力下降。当子代饲粮不额外添加VE时,提高种鸡饲粮VE水平(100、200和400 mg/kg)能提高储存种蛋孵化子代生产性能和抗氧化能力,种鸡饲粮VE添加水平应不低于200 mg/kg。综合结论:1.以产蛋性能和孵化性能作为评价标识,NRC(1994)推荐的肉种鸡VE水平(6 mg/kg)满足延长饲养周期(>70 wk)肉种鸡需要。提高饲粮VE水平(100、200和400 mg/kg)对延长饲养周期(>70 wk)肉种鸡产蛋性能、种蛋孵化性能和子代生产性能无影响,但能增强种鸡、种蛋和雏鸡抗氧化能力。2.以种鸡抗氧化能力以及子代生产性能作为评价标识,延长饲养周期(>70 wk)肉种鸡饲粮VE添加水平可设置为100 mg/kg。3.延长种蛋储存时间增加胚胎死亡率,降低孵化性能、雏鸡质量和子代生产性能。提高种鸡饲粮VE水平缓解种蛋储存诱导的孵化性能下降,涉及氧化应激、细胞凋亡、细胞增殖分化和胚胎发育等显著性富集通路。氧化应激基因Ogg1、Gst、Sod3、Selenop1、Mt3、Pon2和Nrf2以及细胞凋亡和增殖基因Col6a、G0s2、Wnt11、Bok、Casp3、Bax、Bcl2和Hspb8可能是参与其中的关键基因。4.以孵化性能和子代生产性能为评价标识,在种蛋储存时间延长至14天和子代饲粮不额外添加VE条件下,种鸡饲粮VE添加水平应不低于200 mg/kg。更多还原

【Abstract】 Prolonged raise time decreased the laying performance of broiler breeders,egg quality and the growth performance of progeny chicks.As one of the key factors affecting the quality of eggs,prolonged egg storage time decreased the hatchabililty,chick quality and progeny growth performance.Oxidative stress appears to be a potential factor that caused higher mortality of embryos in long-term egg storage.Vitamin E(VE)plays a vital role in preventing oxidative damage.In this study,three experiments were conducted to investigate the effects of broiler breeder dietary VE supplementation on laying performance,egg quality and progeny growth performance,and further investigate the effects of broiler breeder dietary VE levels and egg storage time and their mechanisms of action on hatchability.Exp.1.Effects of dietary VE supplementation on laying performance and antioxidant status of broiler breeder hensExp.1-1 and 1-2 were carried out in the present study.In Exp.1-1,a total of 512 Ross 308 broiler breeder hens(71-wk-old)were allocated into 2 dietary VE treatments(6 and 100 mg/kg)with 8 replicates of 32 hens for 13 wk.Results showed that dietary VE supplementation did not affect the laying performance(P > 0.05).Dietary VE(100 vs.6 mg/kg)increased the ovarian T-SOD activity and T-AOC(P < 0.05),and decreased the ovarian MDA content(P < 0.05).In Exp.1-2,a total of 576 Ross 308 broiler breeder hens(75-wk-old)were allocated into 3 dietary VE treatments(100,200 and 400 mg/kg)with 6 replicates of 32 hens for 12 wk.Dietary VE supplementation did not affect the laying performance(P > 0.05).Serum T-AOC was higher in 400 compared to 100 and 200 mg/kg VE groups(P < 0.05),and ovarian MDA content was lower in 200 compared to 100 mg/kg VE groups(P < 0.05).In conclusion,taking laying performance as response criteria,the recommended level of 6 mg/kg VE by NRC(1994)could meet the requirement of broiler breeder hens beyond 70 wk.Increasing dietary VE(100,200 and 400 mg/kg)levels did not affect the laying performance of broiler breeder hens beyond 70 wk.And,consider the ovary antioxidant status of hens,the suitable VE concentration in breeder hen diet is at least 100 mg/kg.Exp.2.Effects of broiler breeder dietary VE suplementation and egg storage time and their mechanisms of action on the quality of eggsExp.2-1 and 2-2 were carried out in the present study.Exp.2-1 was conducted using a 2 × 2 factorial arrangement with two maternal dietary VE levels(6 or 100 mg/kg)and two egg storage times(stored 0 or 14 d)with 6 replicates per treatment at weeks 8,10 and 12 of Exp.1-1.The storage temperature for eggs stored 14 d were different,with 22-24 ℃ for 1-14 d at week 8,22-24 ℃ for 1-7 d and 16-18 ℃ for 8-14 d at week 10,and 16-18 ℃ for 1-14 d at week 12.Prolonged egg storage time(14 vs.0 d)decreased the egg characteristics and yolk T-AOC(P < 0.05);decreased the hatchability of set/fertile eggs,chick weight,health chick ratio and health chick number per hen(P < 0.05);decreased the chick brain MDA content and T-AOC at weeks 10 and 12(P < 0.05);increased the egg weight loss during storage and embryonic mortality between day 1-7 and 15-21.5 of incubation(P < 0.05);increased the chick serum,brain and yolk sac MDA content and T-AOC(P < 0.05)at week 8;increased the chick serum MDA content and T-AOC;and increased the chick serum T-AOC and yolk MDA content(P < 0.05).Dietary VE levels(100 vs.6 mg/kg)increased the yolk α-tocopherol and T-AOC(P < 0.05);increased the hatchability of set/fertile eggs(P < 0.05);increased the chick serum and yolk sac T-SOD activity and T-AOC(P < 0.05);decreased the embryonic mortality between day 1-7 of incubation(P < 0.05);decreased the yolk and the chick serum,brain and yolk sac MDA content(P < 0.05).Compared to unstored eggs,increasing dietary VE levels present positive effect in the improvement of hatchability and antioxidant status of chicks derived from eggs stored for 14 d.Further investigation indicated that prolonged egg storage time decreased the weight of embryo at day 3 and 7 of incubation(P < 0.05);increased the T-AOC of 7-d-old embryo(P < 0.05);increased the ROS content of 3-and 7-d-old embryo(P < 0.05);and increased the cell apoptosis of 3-and 7-d-old embryo and chick liver and brain(P < 0.05).Increasing dietary VE levels decreased the MDA content of 7-d-old embryo(P < 0.05);decreased the ROS content of chick liver and brain(P < 0.05);and decreased the cell apoptosis of 3-and 7-d-old embryo and chick liver and brain(P < 0.05).Compared to unstored eggs,increasing dietary VE levels present positive effect in the reduction of MDA content of 7-d-old embryo and cell apoptosis of chick liver hatched from stored eggs.The result of embryonic transcriptome demonstrated that the effect of maternal VE levels and egg storage time on the embryonic mortality is related to the pathways involved in oxidative stress,cell apoptosis,cell proliferation and differentiation,and embryonic development.The results of functional gene enrichment and gene m RNA expression indicated that maternal VE supplementation and egg storage time could individually or interactively regulated the expression of oxidative stress-related gene Ogg1,Gst,Sod3,Selenop1,Mt3,Pon2 and Nrf2;and the expression of cell apoptosis and proliferation and and embryonic development-related gene Col6a、G0s2、Wnt11、Bok、Casp3、Bax、Bcl2 and Hspb8.The eggs used in Exp.2-2 were collected at week 9(unstored)and week 12(stored with 16-18 ℃ for 14 d)of Exp.1-2.The egg incubation were both conducted with three treatments(maternal dietary VE 100,200 and 400 mg/kg).Results showed that as maternal dietary VE levels increased,the yolk α-tocopherol and T-AOC increased and MDA content decreased(P < 0.05).As eggs were stored for 14 d,increasing maternal dietary VE levels increased the hatchability of set/fertile eggs and health chick number per hen,and the chick tissue T-AOC(P < 0.05);decreased the embryonic mortality between day 1-7 of incubation,the MDA content of 7-d-old embryo and chicks(P < 0.05).In conclusion,prolonged egg storage time(14 vs.0 d)could suppress the development of embryo and decrease the hatchability and antioxidant status of egg yolks,embryos and newly hatched chicks.Increasing maternal dietary VE supplementation could alleviate these adverse influences induced by long-term egg storage.The effect of maternal VE levels and egg storage time on the embryonic mortality is related to the pathways involved in oxidative stress,cell apoptosis,cell proliferation and differentiation,and embryonic development.The oxidative stress-related gene Ogg1,Gst,Sod3,Selenop1,Mt3,Pon2 and Nrf2;and cell apoptosis and proliferation-related gene Col6a、G0s2、Wnt11、Bok、Casp3、Bax、Bcl2 and Hspb8 were the key genes in the process of VE alleviating these adverse influences induced by long-term egg storage.Taking hatchability as response criteria,the requirement of NRC(1994)meet the need of unstored egg incubation,however,the suitable VE concentration in breeder hen diet is at least 200 mg/kg after egg storage.Exp.3.Effects of broiler breeder dietary VE supplementation and egg storage time on the growth performance and antioxidant status of progeny chicksExp.3-1,3-2,3-3,3-4 and 3-5 were included in the present study.Exp.3-1 was conducted by a 2 × 2 factorial arrangement with two levels of maternal dietary VE levels(6 and 100 mg/kg)and two egg storage times(0 and 14 d).Based on Exp.1-1,after incubation of eggs collected at week 10(stored 0 d)and week 8(stored 14 d with 22-24 ℃),104 chicks originated from each hatched treatment were selected and divided into 8 replicates with 13 chicks(5 males and 8 females)per replicate.After weighed at 21 day of age,males and females in the same replicate of each treatment were divided and adjusted to 4 male replicates and 4 female replicates in each treatment.All chicks received the same pellet diet with an addition of 100 mg/kg VE for 42 d.Prolonged egg storage time decreased the body weight(BW)of 21-and 42-d-old offspring(P < 0.05),body weight gain(BWG)and feed intake(FI)of offspring from 8 to 21 d,1 to 21 d and 22 to 42 d(P <0.05);decreased the liver T-SOD activity of 21-and 42-d-old male offspring(P < 0.05);increased the feed:gain ratio(F/G)of offspring from 1 to 7 d(P < 0.05);and increased the serum and liver MDA content of 7-d-old female offspring(P < 0.05).Maternal dietary VE(100 vs.6 mg/kg)decreased the F/G of offspring from 1 to 7 d(P < 0.05);increased the serum T-SOD activity of 21-d-old male offspring(P < 0.05).Prolonged egg storage time decreased the BW of 21-d-old offspring and BWG of offspring from 22 to 42 d(P < 0.05),and showed no effect on female offspring(P > 0.05).Increasing maternal dietary VE levels decreased the serum MDA content of 7-d-old female offspring and 42-d-old offspring originated from eggs stored for 14 d(P < 0.05),but not for unstored eggs(P > 0.05).Exp.3-2 was conducted by a 2 × 2 factorial arrangement with two levels of maternal dietary VE levels(6 and 100 mg/kg)and two egg storage times(0 and 14 d).Based on Exp.1-1,after incubation of eggs collected at week 12(stored 0 d)and week 10(stored 14 d with 22-24 ℃ for 1-7 d and 16-18 ℃ for 8-14 d),128 chicks originated from each hatched treatment were selected and divided into 8 replicates with 16 chicks(7 males and 9 females)per replicate.After weighed at 7 day of age,males and females in the same replicate of each treatment were divided and adjusted to 4 male replicates and 4 female replicates in each treatment.All chicks received the same pellet diet with an addition of 100 mg/kg VE for 42 d.Results showed prolonged egg storage time decreased the BW of 7-and 42-d-old offspring(P < 0.05),BWG and FI of offspring from 1 to 7 d(P < 0.05);increased the serum MDA content of 7-d-old female and 21-d-old offspring,and the liver MDA content of 42-d-old offspring(P < 0.05).Increasing maternal dietary VE levels decreased the serum MDA content of 7-d-old male offspring and increased the serum T-SOD activity of 42-d-old offspring(P < 0.05).Increasing maternal dietary VE levels increased the serum T-SOD activity of 7-d-old male offspring originated from eggs stored for 14 d(P < 0.05)and decreased the liver MDA content of 7-d-old female offspring originated from eggs stored for 14 d(P < 0.05),but not for unstored eggs(P > 0.05).Exp.3-3 was conducted by a 2 × 2 factorial arrangement with two levels of maternal dietary VE levels(6 and 100 mg/kg)and two egg storage times(0 and 14 d).Based on Exp.1-1,after incubation of eggs collected at week 14(stored 0 d)and week 12(stored 14 d with 16-18 ℃),160 chicks originated from each hatched treatment were selected and allocated into 4 male replicates and 4 female replicates with 20 chicks per replicate.All chicks received the same pellet diet with an adlidition of 100 mg/kg VE for 42 d.Prolonged egg storage time decreased the BW of 42-d-old offspring(P < 0.05),BWG of offspring from 22 to 42 d and 22 to 42 d,and FI of offspring from 8 to 21 d,22 to 42 d and1 to 42 d(P < 0.05);and increased the serum and liver MDA content of 21-and 42-d-old offspring(P < 0.05).Increasing maternal dietary VE levels decreased the serum MDA content of 7-d-old offspring(P < 0.05).Increasing maternal dietary VE levels decreased the serum MDA content of 21-d-old offspring originated from eggs stored for 14 d(P < 0.05),but not for unstored eggs(P > 0.05).Exp.3-4 was conducted by a 3 × 2 factorial arrangement of treatments with three maternal dietary VE levels(100,200 and 400 mg/kg)and two progeny dietary VE levels(0 and 35 mg/kg).After incubation of unstored eggs collected at week 9 of Exp.1-2,240 chicks originated from each maternal dietary VE treatment were selected and divided into 12 pens with 20 chicks(10 males and 10 females).The 12 pens per maternal treatment were randomly assigned to 1 of 2 progeny dietary VE(0 and 35 mg/kg)treatments for 42 d.Results indicated that there was no influence between maternal and progeny dietary VE levels on the growth performance of offsprings(P > 0.05).Exp.3-5 was conducted based on the incubation of stored eggs(stored 14 d with 16-18 ℃)collected at week 12 of Exp.1-2.At hatch,130 chicks originated from each maternal dietary VE(100,200 or 400 mg/kg)treatments were selected and allocated into 5 replicates with 26 chicks(12 males and 14 females).All chicks in the three treatments were fed the same pellet diets with no addition of VE for 42 d.Increasing maternal dietary VE levels increased the BW of 21-,28-,35-and 42-d-old offspring and BWG of offspring from 15 to 21 d and 1 to 42 d(P < 0.05);increased the serum and liver T-SOD activity and the liver T-AOC of offspring(P < 0.05);and decreased the F/G of offspring from 8 to 14 d and 15 to 21 d(P < 0.05);and the liver MDA content of offspring(P < 0.05).In conclusion,prolonged egg storage time(14 vs.0 d)decreased the growth performance and antioxidant status of offspring,and the adverse effect was greater as the egg storage temperature was higher.As progeny diet was added with 100 mg/kg VE,maternal dietary VE(100 vs.6 mg/kg)supplementation was beneficial to the early development of chicks and could partly relieve the reduction of antioxidant status of offspring induced by long-term egg storage.As no addition of VE was present in progeny diet,increasing maternal dietary VE(100,200 and 400 mg/kg)levels could improve the growth performance and antioxidant status of offspring originated from stored eggs,in this case,the suitable dietary VE level for brolier breeder was at least 200 mg/kg.Conclusion1.Taking laying performance and hatchability as response criteria,broiler breeder dietary supplementation of 6 mg/kg VE recommended by NRC(1994)met the need of broiler breeder hens beyond 70 wk.Increasing dietary VE levels did not affect the laying performance of broiler breeder hens beyond 70 wk,hatchability of eggs and growth performance of offspring,however,enhanced the antioxidant status of breeder hens,eggs and newly hatched chicks.2.Taking breeder antioxidant status and progeny growth performance as response criteria,the dietary VE level for broiler breeder beyond 70 wk could be set at 100 mg/kg.3.Long-term egg storage increased the embryonic mortality,and decreased the hatchability,chick quality and progeny growth performance.Increasing maternal dietary VE levels could alleviate the decreased hatchability induced by egg storage,which was related to the pathways involved in oxidative stress,cell apoptosis,cell proliferation and differentiation,and embryonic development.The oxidative stress-related gene Ogg1,Gst,Sod3,Selenop1,Mt3,Pon2 and Nrf2;and cell apoptosis and proliferation-related gene Col6a、G0s2、Wnt11、Bok、Casp3、Bax、Bcl2 and Hspb8 were the key genes.4.Taking hatchability and progeny growth performance as response criteria,as eggs were stored for 14 days and progeny diet was prepared with no addition of VE,the suitable dietary VE level for broiler breeder was at least 200 mg/kg.更多还原