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1.
为研究印楝素乳油对井上蛀果斑螟(Assara inouei Yamanaka)的致死效果及对后续虫态发育的影响。在室内条件下,采用饲喂法和浸渍法,研究了0.3%印楝素乳油对井上蛀果斑螟初孵幼虫和老熟幼虫发育、存活,及存活幼虫化蛹、羽化和成虫生殖力的影响。结果表明,0.3%印楝素乳油对井上蛀果斑螟幼虫的生长发育和繁殖均有一定的抑制作用。不同浓度印楝素乳油处理初孵幼虫和老熟幼虫后,其幼虫存活率、化蛹率、羽化率均显著低于对照,且随处理浓度的增加而逐渐降低;其蛹期、成虫产卵前期、寿命与对照无显著差异,而蛹重、产卵期与对照差异显著;成虫单雌产卵量及卵孵化率显著小于对照,产卵抑制率及卵孵化抑制率均随处理浓度的增加而逐渐增大;印楝素对初孵幼虫的抑制作用明显大于老熟幼虫。  相似文献   

2.
在云南省西双版纳种植区发现为害澳洲坚果的新害虫——脊胸露尾甲,为准确掌握其生物学习性,在室内以澳洲坚果果仁为食对其进行了饲养,并对各虫态的形态、成虫交配习性、产卵习性、卵的孵化率、各虫态的存活率进行了观察。结果表明:脊胸露尾甲的发育经历卵、幼虫、蛹、成虫四个虫态,其中幼虫分为3个龄期,随着龄期的增长,幼虫体长、体宽和头壳宽度逐渐增加。成虫羽化后不会立即交配,交配前期为(4.65±0.04)d,交配时长不等,初次交配时长为(13.78±0.29)min,雄成虫存在争夺交配权的行为。雌成虫产卵前期为(8.65±0.03)d,初次产卵量为(1.94±0.06)粒,在15:00-18:00时间段的产卵量/小时最高;雌成虫对产卵位置具有选择性,背光面的着卵率极显著高于向光面。卵的孵化率随着湿度的增加而不断提高。常规饲养条件下,卵、1龄幼虫、2龄幼虫、3龄幼虫、蛹的存活率分别为(86.50±0.69)%、(83.31±2.99)%、(94.85±0.71)%、(97.09±1.46)%、(98.77±1.23)%。本研究为脊胸露尾甲的生物学及防治提供参考依据。  相似文献   

3.
温湿度对黑水虻繁殖率及幼虫转化鸡粪效率的研究   总被引:1,自引:0,他引:1  
为了探讨山东地区冬季黑水虻成虫繁殖的最佳温湿度环境以及幼虫对新鲜鸡粪的转化效率,对不同饲养温度和湿度下黑水虻虫蛹羽化率、平均产卵量和虫卵孵化率等指标进行测定,分析幼虫增重、料虫比、干物质转化率以及采食速度等指标的变化规律.结果表明:黑水虻虫蛹在本试验条件下均能正常羽化(P>0.05);27 ℃、30 ℃温度条件下与24...  相似文献   

4.
[目的]研究饲料中添加氯化钠对黑水虻(Hermetia illucens L.)生长性能及幼虫肠道、饲养基质微生物群落多样性的影响。[方法]以无添加氯化钠饲料饲喂的黑水虻为对照组,饲喂添加0.7%、2.0%氯化钠饲料的黑水虻为试验组。试验周期为6日龄幼虫至成虫产卵。对饲喂不同含量氯化钠饲料的黑水虻的生长性能指标、生长周期指标进行统计,并利用16S rDNA序列分析技术研究黑水虻幼虫肠道及饲养基质微生物群落的变化。[结果](1)饲喂添加0.7%氯化钠饲料的黑水虻,体长、体重(除9日龄外)、饲料转化率、饲料利用率、料重比、幼虫鲜质量及总增鲜质量、蛋白质含量、脂肪含量、存活率、化蛹率、羽化率、羽化时间以及产卵时间与对照组相比均无显著(P>0.05)差异。(2)与对照组相比,饲喂添加2.0%氯化钠饲料的黑水虻,9~18日龄幼虫的体长、体重均显著(P<0.05)降低;饲料减重率、表观消化率显著(P<0.05)降低,饲料转化率显著(P<0.05)提高,饲料利用率、料重比无显著(P>0.05)变化;脂肪含量显著(P<0.05)提高,幼虫的鲜质量、总增鲜质量及蛋白质...  相似文献   

5.
不同时期补充营养对黄粉虫繁殖力的影响   总被引:1,自引:0,他引:1  
为了研究黄粉虫在不同发育时期补充不同浓度的葡萄糖、蔗糖、蜂蜜对成虫繁殖力的影响,试验采用多因素对比饲养的方法,测定黄粉虫成虫繁殖力相关指标(寿命、孵化率、产卵量)。结果表明:幼虫和成虫期补充营养组黄粉虫繁殖力大于成虫期补充营养组,但二者间差异不显著(P0.05);成虫期补充营养组黄粉虫繁殖力显著大于幼虫期补充营养组(P0.05)。在不同时期补充相同浓度营养对黄粉虫卵的孵化率差异不显著(P0.05);同一时期补充不同浓度营养对黄粉虫卵的孵化率差异显著(P0.05)。成虫期补充10%葡萄糖组黄粉虫产卵量与其他组存在显著差异(P0.05),雌成虫的寿命最长约为132 d,雄成虫的寿命最长约为139 d;最佳产卵期是羽化后10~55 d,孵化率可达94.29%。  相似文献   

6.
抗坏血酸又称维生素C(Vc),是家蚕幼虫生长发育必需的营养物质。为探讨在非取食阶段家蚕体内还原型抗坏血酸(AsA)的来源,采用分光光度法测定家蚕在不同发育时期以及不同条件下体内的AsA含量和总抗坏血酸(TAA)含量变化,并采用实时荧光定量PCR检测AsA合成相关酶基因在家蚕不同发育阶段的表达量变化。滞育卵中AsA含量在产卵24 h内,TAA含量在产卵72 h内均有所增加,此后二者的含量均不同程度降低并一直保持相对稳定;即时浸酸解除滞育蚕卵的AsA含量在产卵24 h内显著增加,且在产卵48~144 h一直保持较高水平,到胚胎发育后期又明显下降,但AsA含量一直高于滞育卵。幼虫期取食桑叶或添加Vc的人工饲料之后,蚕体内AsA和TAA含量均增加,幼虫在眠中或取食缺乏Vc的人工饲料及饥饿一定时间后,体内的AsA和TAA含量均明显降低,尤其是饥饿后体内的AsA含量会下降到很低的水平。蛹期的TAA含量无显著变化,但雌蛹体内AsA含量在化蛹0~24 h显著升高,雄蛹体内AsA含量在化蛹0~144 h一直保持较高水平,到蛹后期才有较为明显的下降。编码AsA合成相关酶的4个同源基因BmG ULO_like1、BmG ULO_like2、BmA Lase_like1、BmA Lase_like2在中肠和脂肪体中的表达量总体上都是卵期及蛹期显著高于幼虫期,并且随卵和蛹的发育进程呈上升趋势。研究结果提示,家蚕胚胎发育期和蛹期的AsA来源途径,可能包括自身合成途径及由氧化型抗坏血酸(DHA)还原为AsA的途径,而在幼虫期主要从食物中吸收Vc,缺乏其他来源。  相似文献   

7.
分别在家蚕4龄眠起与5龄眠起时推迟饷食以及在5龄第3天进行饥饿处理,调查蚕体的生长发育、产茧和产卵情况,为制定新的家蚕共育模式技术规范以及一代杂交种生产的发蛾调节技术规范等提供试验依据。4龄起蚕推迟8 h饷食对幼虫5龄经过、全茧量、茧层量、茧层率、蛹体质量及蚕蛾羽化率、产卵量和良卵率均没有不利的影响;推迟16 h、24 h饷食,雌蚕的5龄经过延长及熟蚕体质量、全茧量、蛹体质量等性状成绩显著下降(P0.05),对雄蚕的影响较小(P0.05)。5龄起蚕分别推迟8 h、16 h、24 h饷食,5龄经过延长,熟蚕体质量、全茧量、茧层量、蛹体质量及产卵量、良卵数量等均显著下降(P0.01)。5龄第3天幼虫分别饥饿12 h、24 h,熟蚕体质量、全茧量、茧层量和蛹体质量均显著下降(P0.01);饥饿48 h后结茧率显著下降(P0.01),雌蚕和雄蚕分别仅为60.67%、42.66%。依据试验结果建议:农村养蚕如采用集中共育至4龄起蚕的模式,为方便共育蚕的分发配送,可适当推迟4龄起蚕的饷食时间,但推迟时间不应超过8 h;家蚕一代杂交种生产过程可将4龄起蚕饷食时间推迟8~16 h,调节对交品种发育进度;无论丝茧育还是种茧育,均不宜使旺盛生长期的5龄幼虫遭受饥饿,需预先调节好桑叶的充足供给。  相似文献   

8.
关振英 《蜜蜂杂志》2010,30(3):29-29
<正>1蜂螨的繁殖特点1.1繁殖速度快当蜂群内子脾出现大幼虫时,雌螨侵入幼虫房内产卵,24小时内卵发育成若螨。幼螨靠蜜蜂幼虫、蛹体的营养发育成长。生命周期雄螨为6.5天,雌螨为7天。当蜂群大量繁育雄蜂时,雌螨喜欢在营养丰富的雄蜂幼虫房内产卵繁殖。  相似文献   

9.
陈德霞 《蜜蜂杂志》2020,40(2):26-27
1巢虫巢虫是严重危害养蜂业的害虫之一,尤其对中蜂影响大,要做到早发现、早防治。巢虫是蜡螟的幼虫,分为大蜡螟和小蜡螟2种。属于完全变态昆虫,包括卵、幼虫、蛹和成虫4个发育阶段。北方地区小蜡螟发病较多,小蜡螟雌螟长9~11 mm,寿命可达25~30 d。白天隐藏于蜂箱、巢脾缝隙或箱外隐蔽处,夜间在巢内活动,常在箱底蜡屑中产卵。1只雌螟每分钟可产卵60~80粒,一生总产卵量200~1600粒。卵于1周后孵化成幼虫(巢虫),1~3 d爬上巢脾后,食量猛增,蛀食巢脾、蜜粉,钻隧道毁坏巢脾,咬伤、咬死幼虫,致使蛹不能封盖,造成所谓的"白头蛹"。  相似文献   

10.
黑粉虫体内所含的几种重要氨基酸与黄粉虫可取长补短,尤其胱氨酸的含量较高,这是其他食物所不能比拟的,而胱氨酸是蜕皮所不可缺少的物质。黑粉虫较黄粉虫生长发育缓慢得多,在温度平均25℃时,发育周期需要8个月。幼虫需14周蜕14次皮而化蛹。蛹经半个月而羽化为成虫,成虫期为3个月。成虫半个月后开始产卵,每雌虫能产卵400粒,卵经15d后孵化为幼虫。幼虫期较长,需6个月左右。①幼虫。长圆筒状,老熟幼虫长可达3.5cm。②成虫。体形稍大于黄粉虫。暗黑色,鞘翅上无金属光泽。触角末节长度小于宽度。第三节长度大于或等于第一二两节之和。其他形态与黄粉虫相同。  相似文献   

11.
本试验旨在探讨饲粮中添加白酒糟酵母培养物对产蛋鸡生产性能、免疫机能及肠黏膜结构的影响。选取324只27周龄、产蛋率和体重相近的健康海兰褐蛋鸡,随机分成3个组,每组6个重复,每个重复18只鸡。3组产蛋鸡分别饲喂添加0(对照)、1%和2%白酒糟酵母培养物的玉米-豆粕型饲粮,试验分为预试期1周和正试期8周。结果表明:1)各时间段内各组间产蛋率差异不显著(P0.05),但1%白酒糟酵母培养物组产蛋率在1~4周、5~8周和1~8周比对照组分别提高了1.79%、2.07%和1.93%;1%白酒糟酵母培养物组5~8周和1~8周的平均日采食量有高于对照组的趋势(P0.10)。2)在第4周末,2%白酒糟酵母培养物组血清球蛋白含量较对照组和1%白酒糟酵母培养物组分别提高了19.0%(P0.10)和27.2%(P0.05),1%和2%白酒糟酵母培养物组血清磷含量均显著高于对照组(P0.05)。3)在第4周末,与对照组和1%白酒糟酵母培养物组相比,2%白酒糟酵母培养物组血清免疫球蛋白G和免疫球蛋白M含量均显著提高(P0.05);在第8周末,与对照组相比,2%白酒糟酵母培养物组血清免疫球蛋白A和免疫球蛋白M含量显著提高(P0.05),1%白酒糟酵母培养物组血清溶菌酶活性显著提高(P0.05)。4)与对照组和2%白酒糟酵母培养物组相比,饲粮中添加1%白酒糟酵母培养物显著提高了产蛋鸡空肠绒毛高度和隐窝深度(P0.05),有提高绒毛高度/隐窝深度的趋势(P0.10)。综上可知,产蛋鸡饲粮中添加适量(1%~2%)白酒糟酵母培养物可增强免疫机能,改善肠黏膜结构。  相似文献   

12.
选取30周龄海兰灰蛋鸡240只,随机分成4组,饲喂不同添加量的红曲米,研究其对生产性能的影响。结果表明,在蛋鸡日粮中添加1‰的红曲米,可以提高产蛋率、平均蛋重,降低料蛋比;随着红曲米添加量的增大,产蛋率、平均蛋重反而低于对照组,料蛋比高于对照组。说明在蛋鸡日粮中添加适量的红曲米,可以提高蛋鸡的生产性能。  相似文献   

13.
为了研究虫草粉(古尼虫草地顶孢霉培养物)联合酵母硒对蛋鸡产蛋性能、蛋品质、抗氧化功能和免疫功能的影响,试验选用450羽24周龄海兰褐壳蛋鸡,随机分为5组,每组6个重复,每个重复15羽。对照组饲喂基础饲粮,试验Ⅰ~Ⅳ组饲喂添加0.1 mg/kg酵母硒联合不同剂量虫草粉(0、0.2%、0.3%和0.4%)的基础饲粮,试验期27周;选取产蛋高峰中期(第40周龄)蛋鸡进行产蛋性能、鸡蛋品质、免疫功能和抗氧化功能分析。结果显示,与对照组相比,产蛋高峰中期试验Ⅲ组蛋鸡的产蛋率、平均蛋重均显著提高,料蛋比显著降低(P<0.05);鸡蛋哈夫单位、蛋壳颜色、蛋壳强度、蛋黄颜色、蛋清粗蛋白质含量、蛋黄粗蛋白质和粗脂肪含量均显著升高(P<0.05),蛋清中必需氨基酸Leu、Lys、Met、Trp、Phe、Thr、Val和His及非必需氨基酸Ala、Asp、Glu、Pro和Tyr水平也显著增加(P<0.05);试验Ⅳ组蛋鸡的蛋壳颜色、蛋壳强度、哈夫单位和蛋清粗蛋白质含量均显著提高(P<0.05),蛋清中必需氨基酸Ile、Gly、Arg和非必需氨基酸Cys、Ser水平均显著增加(P<0.05);试验Ⅰ~Ⅳ组蛋鸡蛋黄、蛋清中硒含量均显著增加(P<0.05)。同时,与对照组相比,产蛋高峰中期试验Ⅲ组蛋鸡血清MDA含量显著下降(P<0.05),WBC数量、血清IFN-γ和IL-2水平及T-AOC和T-SOD活性均显著升高(P<0.05)。结果表明,饲粮中联合添加酵母硒和适量的虫草粉能明显提高产蛋高峰中期蛋鸡的产蛋性能和鸡蛋品质,增强机体免疫力和抗氧化能力,以0.1 mg/kg酵母硒联合添加0.3%虫草粉的效果最佳。  相似文献   

14.
选择28周龄体重相近、健康的海兰褐蛋鸡1.8万羽,随机分成4组,分别饲喂基础饲粮(A组,对照组)、基础饲粮+100 g/t益生素(B组)、基础饲粮+800 g/t酵母细胞壁(C组)、基础饲粮+50 g/t益生素+400 g/t酵母细胞壁(D组),至50周龄结束。结果显示:(1)试验各组间蛋鸡日采食量、平均蛋重没有显著差异,但D组平均蛋重较A组提高了1.19%(P0.05)。与A组相比,试验组蛋鸡产蛋率均有不同程度提高,其中D组蛋鸡产蛋率提高了2.97%(P0.05),且高于单独添加的B组、C组(P0.05);与A组相比,料蛋比均有不同程度下降,其中D组料蛋比下降了1.42%(P0.05),且低于单独添加的B组、C组(P0.05)。(2)与A组相比,除B组略降低,C组、D组哈夫单位均不同程度提高,但差异均不显著(P0.05);与A组相比,各试验组蛋黄颜色均不同程度变深,但差异不显著(P0.05)。各组蛋壳厚度差异不显著(P0.05)。结果表明:在蛋鸡饲粮中单独添加益生素、酵母细胞壁,或将益生素与酵母细胞壁复合添加均可不同程度提高蛋鸡的生产性能和蛋品质,复合添加(基础饲粮+50 g/t益生素+400 g/t酵母细胞壁)的效果更佳。  相似文献   

15.
This study was designed to investigate the effects of yeast culture supplementation to laying hen diets containing 2 oilseed meals on performance, egg traits, and some blood parameters. A total of 180 Lohmann Brown laying hens 21 wk of age were allocated to 4 dietary treatments and fed for 16 wk. Two different basal diets were prepared; one contained soybean meal and the other contained sunflower seed meal. Both of the basal diets were supplemented with 0 and 2 g/kg commercial yeast culture product (Saccharomyces cerevisiae). Yeast culture supplementation to diets containing either oilseed meal did not significantly affect feed intake, hen-day egg production, feed efficiency, interior and exterior egg quality characteristics, serum levels of total protein, triglyceride, cholesterol, alanine amino transferase, aspartate amino transferase, and alkaline phosphatase. Body weight gain (P < 0.05), egg weight (P < 0.001), and serum uric acid (P < 0.05) were increased with yeast culture supplementation. The reduction in egg yolk cholesterol was significant (P < 0.001) in the groups fed yeast-supplemented diets. The results in this study demonstrated that yeast culture supplementation to the diets containing soybean meal or sunflower seed meal increased egg weight and decreased egg yolk cholesterol without affecting performance and egg traits, but serum uric acid concentration was increased.  相似文献   

16.
本试验旨在研究酵母硒和亚硒酸钠作为硒源对产蛋高峰期蛋鸡生产性能、蛋硒含量、蛋品质以及储存期内蛋品质的影响。选用27周龄600只产蛋高峰期海兰褐蛋鸡,随机分为2个处理,每个处理3个重复,每个重复100只鸡。在日粮中分别添加0.2 mg/kg的亚硒酸钠和酵母硒(试验日粮实测硒含量分别为0.227、0.233 mg/kg),预试期1周,正试期8周,对鸡蛋28 d内的鸡蛋蛋品质进行跟踪检测。结果表明:酵母硒和亚硒酸钠对海兰褐蛋鸡生产性能的影响不显著;与亚硒酸钠组相比,酵母硒组对28 d鸡蛋蛋品质无显著影响,但可显著提高56d鸡蛋的蛋白高度和哈氏单位(P<0.05);与添加亚硒酸钠相比,添加酵母硒减缓了储存期鸡蛋哈氏单位的降低,有利于延长鸡蛋货架期;酵母硒组蛋黄、蛋清中硒含量显著高于亚硒酸钠组(P<0.05)。由此可见,相较于亚硒酸钠,饲喂含酵母硒的日粮在延长鸡蛋货架期、提高蛋黄和蛋清中的硒沉积方面效果更好。  相似文献   

17.
1. Lohmann White and Lohmann Brown egg-type hybrids were reared on 6-, 8-, 10- or 12-h photoperiods, transferred to 12.5 h at 18 weeks and then given weekly increments to reach 14 h at 21 weeks. In a second experiment, Lohmann White pullets from the same rearing facility were transferred abruptly to 14 h at 18 weeks. 2. Body weight gain and feed intake to 6 and 18 weeks were positively correlated with rearing photoperiod in both breeds. Mortality to 18 weeks was unaffected. 3. Whether the photoperiod was increased abruptly or in a series of increments, Lohmann White pullets reared on 6 or 8 h matured 4 to 6 d later than pullets reared on 10 or 12 h. Rearing day-length had little effect on sexual maturity in Lohmann Brown pullets. 4. In both genotypes and each experiment, egg numbers, egg weight and shell strength increased with rearing photoperiod. Feed intake in the laying period was not significantly affected by rearing day-length, but a meta-analysis of all data showed a significant, though small, increase in adult feed intake with rearing photoperiod. Despite Lohmann White birds reared on 6 and 8 h having lower body weights throughout the laying period, they had larger body weight gains between 18 and 70 weeks than those reared on 10 or 12 h. There were no clear effects of rearing photoperiod on albumen height or mortality. 5. The heavier eggs and stronger shells of the birds reared on the longer day-lengths were correlated with heavier body weights at 18 weeks, and the superior egg numbers and higher feed intake were associated with age at sexual maturity.  相似文献   

18.
The purpose of this study was to evaluate the effect of yeast with bacteriocin from Ruminococcus albus 7 (albusin B) on physiological state and production performance of laying hens. One hundred and twenty 26‐week‐old Single Comb White Leghorn (Hyline) laying hens were assigned into five groups including: (i) control group, (ii) yeast control (YC), (iii) 0.125% yeast with bacteriocin (0.125B), (iv) 0.25% yeast with bacteriocin (0.25B) and (v) 0.5% yeast with bacteriocin (0.5B). All supplements were added to the experimental diets of the hens from 26 to 46 weeks of age. Samples were collected every 4 weeks. Blood samples were collected from the wing vein for blood biochemical parameters assay, and faecal samples were collected by swab for the microbiota test. The egg production performance was recorded daily, and fresh eggs were collected for quality test. The blood biochemical assay results indicated that the addition of yeast with bacteriocin decreased the AST (aspartate aminotransferase) activity and it also affects the lactate concentration in laying hen blood. The result of egg quality indicated that yeast with bacteriocin supplementation had no effect on the mass of yolk and the strength of eggshell, but it had positive effect on the laying performance under hot environment. Low concentration bacteriocin (0.125B) supplementation could decrease total yolk cholesterol. The faecal microbiota result indicated that the supplementation of bacteriocin increased the lactobacilli counts. The yeast with bacteriocin supplementation significantly decreased the clostridia counts under hot environment condition, especially in hens receiving 0.25B. Combining the data from clinic chemistry, faecal microbiota, egg production and egg quality, the 0.25B supplementation may result in the best physiological parameter and egg production performance of laying hen.  相似文献   

19.
王显 《中国饲料》2021,1(6):21-24
文章旨在评估不同饲养方式对蛋鸡生产性能、蛋品质和血清生化指标的影响。试验选择产蛋性能接近的22周龄海兰褐壳蛋鸡540只,随机分为3组,每组5个重复,每个重复36只。笼养组蛋鸡采用三层阶梯饲养(0.6 m2/只),网上平养组蛋鸡在金属网丝上饲养(1.5 m2/只),垫料平养组在平铺20 cm稻壳的水泥地板上平养(1.8 m2/只)。试验共开展28周,包括2周的适应期。结果:网上平养和垫料平养组24~36 w和24~29 w蛋鸡平均日采食量较笼养组蛋鸡分别显著提高5.71%、6.22%和4.81%、4.48%(P<0.05)。此外,垫料平养组24~36 w和24~49 w蛋鸡的料重比较笼养组分别显著提高7.31%和4.09%(P<0.05)。在36 w时,垫料平养组鸡蛋的蛋壳强度最高,脏蛋率最低(P<0.05)。在49 w时,笼养组鸡蛋的蛋壳厚度最低(P<0.05),脏蛋率最高(P<0.05)。笼养组蛋鸡血清葡萄糖、甘油三酯、总蛋白和胆固醇浓度均最高(P<0.05),但高密度脂蛋白浓度最低(P<0.05)。结论:网上平养和垫料平养可以提高蛋鸡采食量,但笼养蛋鸡的饲料效率表现最佳。此外,垫料平养提高了鸡蛋的蛋壳强度和蛋壳厚度,降低了破蛋率。  相似文献   

20.
The effects of the growth curve from 15 to 20 weeks, age at photostimulation and pattern of photostimulus on sexual maturity, egg production and egg weight were evaluated in two trials with broiler breeder females to 56 and 34 weeks of age (housed in litter pens and individually caged, respectively). Carcase composition and reproductive morphology of hens varying in laying efficiency were measured in the second trial. Trial 1: Four growth curves were applied from 15 to 20 weeks to pullets housed in litter pens. Birds were transferred from 8- to 10-h photoperiods at 20 or 24 weeks of age, followed by weekly increments of one hour to reach a 16-h final photoperiod. Lower-than-recommended body weights at 20 weeks significantly delayed sexual maturity, reduced peak rate of lay, total eggs and mean egg weight. However, double-yolked egg production was lower, resulting in non-significant differences in settable egg numbers between body weight treatments. Birds reared to the heaviest body weight exhibited a significantly advanced sexual maturity, but total egg numbers, peak rate of lay and mean egg weight were not significantly affected. However, the laying of more double-yolked eggs resulted in a decrease in the number of settable eggs. Delaying photostimulation to 24 weeks significantly retarded sexual maturity, reduced total and settable egg numbers, and increased mean egg weight. A tendency for fewer double-yolked eggs was observed. Trial 2: At 19 weeks, birds were selected from the 4 body weight categories in Trial 1 and moved to individual cages in 8 rooms. Five lighting programmes were applied. The pattern of photostimulation applied did not affect any of the production traits measured. At 34 weeks, 24 birds were selected for the analysis of reproductive morphology, presence of internal or multiple ovulations, and carcase composition. Eight hens showing an early age at first egg and regular egg production records, 8 birds showing erratic laying performance and 8 non-layers were killed for this purpose. There were no differences in carcase composition or reproductive morphology between these groups. No internal ovulations or double or multiple ovarian hierarchies were observed. The results presented confirm that broiler breeders do not require a lighting stimulus in order to initiate ovarian activity and that, where no lighting stimulus is given, body weight or feeding level plays a critical role in stimulating the birds to attain sexual maturity. However, when a lighting stimulus is given, factors such as body weight and body composition become relatively less important in regulating the age at sexual maturity.  相似文献   

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