共查询到18条相似文献，搜索用时 218 毫秒
1.
现行蛋种鸡本交笼虽具备较大活动空间并能满足鸡只自然交配行为,但其饲养环境依然相对贫瘠,缺乏环境富集装置,存在啄羽啄肛等行为问题。该文探究了蛋种鸡本交笼中3种不同类型产蛋窝的使用效果及其对啄羽啄肛行为及生理应激反应的影响。结果表明,3种产蛋窝Nest1(长?宽?高)(90 cm?40 cm?60 cm)、Nest2(45 cm?40 cm?60 cm)、Nest3(70cm?52cm?60cm)在32周龄时窝内蛋比例分别为80.5%?7.8%、67.4%?8.1%、87.3%?7.6%,Nest1与Nest3窝内蛋比例、探窝次数及趴卧次数显著高于Nest2(P0.05),Nest1、Nest2、Nest3产蛋鸡只探窝时间无显著差异,设置产蛋窝后鸡只发出的攻击性啄、严重啄羽、轻度啄羽频次显著低于对照组(P0.05)。3种产蛋窝血浆皮质酮浓度无显著差异,但显著低于对照组(P0.05),对照组及Nest2总死淘率显著高于Nest1与Nest3(P0.05),对照组因啄死淘率显著高于Nest1、Nest2、Nest3(P0.05)。产蛋窝的设置可以满足鸡的行为需求,降低啄羽啄肛行为的发生、生理应激及因啄死淘发生风险。 相似文献
2.
为明确人工光环境下后备母猪的适宜光照强度,该研究搭建了一套猪舍光环境偏好性选择系统,以LED白光（400～700 nm）为人工光源,设置4种光照强度（40、100、350、1200 lx）,每7 d为一个周期对单元猪舍对应的光照方案进行调整,光照时长16 h,以24头二元杂交后备母猪为试验对象,进行了为期28 d的试验,探究后备母猪对人工光环境光照强度的偏好性选择规律。结果表明,在猪只数量的时空分布方面,相较于40、350、1200 lx,后备母猪在开灯期间表现出对100 lx光照强度的显著性偏好（P<0.05）,占整体数量29.33% ± 1.14%;猪群对其余3种光照强度的偏好呈现明显的节律性,表现为开灯后和关灯前3 h对40 lx光照强度的偏好显著高于350、1200 lx（P<0.05）;在猪只活跃度方面,开灯后的前6 h,较强光照组（350 lx: 37.97% ± 3.47%和1200 lx：35.42% ± 4.04%）的猪只活跃度显著高于较弱光照组（40 lx: 27.90% ± 8.44%和100 lx: 23.94% ± 3.79%）;在猪只采食方面,较强光照（350、1200 lx）组后备母猪的饲料消耗量和采食时长均高于较弱光照组（40、100 lx）。由此,建议后备母猪舍的照明制度中设置一定的光照过渡阶段,以100 lx光照强度为主,开灯后和关灯前3 h使用40 lx较弱光环境避免刺激,此外,可在09:00—11:00增加2 h较强光照（350 lx）增加猪只活动量。该研究结果可为后备母猪舍光环境精准调控提供理论参考依据。 相似文献
3.
LED光源R／B对叶用莴苣生理性状及品质的影响 总被引：5，自引：0，他引：5
研究不同红／蓝（R／B）光强配比对叶用莴苣（LactucasativaL．）生理性状及品质方面的影响,以便为新型人工光源在莴苣生产上的应用提供理论依据。试验利用波长为660nm（±20nm）红光与450nm（±20nm）蓝光发光二极管（LightEmittingDiode,LED）作为人工光源,设置3个R／B试验处理,分别为LED1（R／B=10）、LED2（R／B=8）、LED3（R／B=6）,以1个荧光灯处理为对照（CK）,选用水耕栽培模式在不同光照环境下培育叶用莴苣30d。结果表明：660nm红光和450nm蓝光组合可以有效提高莴苣的光能利用率,促进光合作用;适宜的红蓝光比例能有效增加植物Vc含量,并降低硝酸盐含量。其中,处理LED2（R／B=8）的叶用莴苣净光合速率及Vc含量明显高于其他试验处理,而硝酸盐含量最低,表现出良好的生理和品质特性,因此,R／B=8相对更适宜叶用莴苣的生长发育。 相似文献
4.
红蓝光质对香椿芽苗菜营养品质的影响 总被引：1，自引：0，他引：1
以发光二极管（LED）精量调制光质（红光、蓝光和红蓝混合光）,以白光（普通日光灯）为对照,研究红蓝光质对香椿芽苗菜营养品质（氨基酸、维生素C、硝酸盐、粗纤维、总黄酮、单宁）的影响。结果表明：与白光相比,蓝光和红蓝光处理显著提高了香椿芽苗菜氨基酸含量,而红光处理降低了香椿芽苗菜氨基酸含量;3种光质均有利于香椿芽苗菜维生素C 的形成和累积,其促进作用大小依次为蓝光＞红光＞红蓝混合光;各处理均抑制香椿芽苗菜硝酸盐的累积,其中红光的抑制作用最强;红光处理可提高香椿芽苗菜的粗纤维含量,而蓝光处理则降低香椿芽苗菜粗纤维含量;与对照相比,蓝光和红蓝混合光处理提高了香椿芽苗菜总黄酮的含量,同时降低了香椿芽苗菜单宁的含量。总之,蓝光和红蓝混合光处理可提高氨基酸、维生素C、总黄酮含量,同时可降低硝酸盐、粗纤维和单宁含量。因此,蓝光和红蓝混合光处理更有利于提高香椿芽苗菜品质。 相似文献
5.
为研究鸡卵细胞卵黄生成受体（Occyte vitellogenesis Receptor , OVR）对鸡产蛋性能及蛋品质的影响,本试验以六个鸡种（洪山鸡、江汉鸡、双莲鸡、郧阳大鸡、郧阳白羽乌鸡、海兰褐）的一代混交群体390个个体为研究材料,采用PCR-SSCP、PCR-RF-SSCP及测序的方法进行鸡ovr基因内含子单核苷酸多态性（SNPs）位点筛选,并与鸡群蛋用性状进行关联分析。结果表明,在鸡ovr基因中发现内含子2 T3967G,内含子7 C8099T、A8296G,内含子9 A8839T、G9084A共5个突变位点;其中内含子2 HinfⅠ突变位点与开产日龄、蛋壳厚度相关极显著（p<0.01）,与产蛋量、蛋重、蛋黄比例相关显著（p<0.05）;三种基因型中TT个体在开产日龄、平均产蛋量、蛋重、蛋黄比例等方面都优于其它基因型个体。本研究结果证实了其他学者研究的结论,即ovr基因对鸡的产蛋性能和蛋品质性状有重要的影响。 相似文献
6.
不同LED光源对番茄果实转色期品质的影响 总被引：16，自引：6，他引：10
采用新型半导体光源发光二极管（LED）精量调制光质（红光、蓝光和红蓝组合光）,以普通日光灯（白光）为对照,研究不同光质对番茄果实转色期品质的影响。结果表明,红光处理下番茄果实番茄红素含量最高,显著高于对照和其他处理,但Vc含量最低。蓝光处理下番茄果实维生素C（Vc）含量、可溶性蛋白含量均显著提高。红蓝组合光处理番茄果实Vc含量与对照差异不明显,但可溶性蛋白的含量显著提高。红光和红蓝组合光处理能够显著提高番茄果实糖、酸含量;各处理糖酸比均显著高于对照,且红蓝组合光处理番茄果实的糖/酸值最高。红光和蓝光是影响番茄果实转色期品质变化的主要光质。 相似文献
7.
免疫抑制素提高粤黄鸡产蛋性能的研究 总被引：9，自引：1，他引：9
将鸡抑制素α亚基成熟肽cDNA片段克隆入表达载体pRSETA的BamHⅠ和HindⅢ位点之间,在大肠杆菌(Es-cherichiacoli)BL21(DE3)中表达了分子量为15.8kD左右的重组鸡抑制素融合蛋白,在0.005mmol/LIPTG诱导4h时达最高表达量,约占总菌体蛋白的37%。将此融合蛋白用Ni-NTA树脂经亲和层析纯化后与矿物油佐剂制成蛋白含量为1mg/mL的免疫原。对25只240日龄的粤黄鸡种(Gallusgallus)母鸡在第5和第26天肌肉注射1mL重组鸡抑制素融合蛋白免疫原,另外25只种鸡接种1mL不含蛋白的油乳剂。免疫组鸡在首次免疫后血浆抗重组鸡抑制素的抗体水平持续且极显著高于对照组(P<0.01)。在50d试验期内,免疫组鸡的产蛋量在第2次免疫后明显高于对照组约5%￣8%左右,表明鸡免疫抑制素重组融合蛋白仅能有限地提高其产蛋性能。 相似文献
8.
蝗虫对光谱光照特性趋光反应的对比及数学分析 总被引：3，自引：3，他引：0
为给蝗虫灾害光电诱导机械化捕集技术中诱导光源光照参数的选取及设计提供技术支持,该文利用LED光源和自制的行为反应试验装置采用对比试验法,进行了蝗虫趋光选择最佳的光谱优选,并测试了蝗虫趋光行为反应的光照阈值,探讨了不同光谱和光照度对蝗虫趋光行为影响的机理。结果显示：相同光照度条件下,蝗虫对紫光（405?nm）的内在趋光反应率最高,对紫绿蓝（520+465+405?nm）组合光的反应次之;蝗虫对紫（405?nm）、绿（520?nm）、蓝（465?nm）及组合光的趋光反应率数学模型求解表明,蝗虫对不同光谱的趋光反应存在最高趋光光照度值和最低灵敏光照度值,其中紫光对二者的光照度最低;蝗虫的趋光响应受光谱和光照度的影响,在绿、紫、蓝光谱组合的光照度值内提高光照强度可达到蝗虫对紫光反应的逼近效果。 相似文献
9.
不同光照条件下蚯蚓避光性运动与蚓粪机械化分离参数量化 总被引：5，自引：5，他引：0
蚯蚓和蚯蚓粪的机械化分离是目前蚯蚓规模化养殖业亟需解决的瓶颈问题之一,针对目前最常用的蚯蚓光分离工艺方法在实际养殖分离中全凭人为经验、效率低、无机械化参数等问题,探究了不同光质条件:白光、黄光、绿光、蓝光、红光、白炽灯光在10~270 lx不同光照强度下,对照实际自然环境场景:室内光照、室外阴处光照和太阳光直射光照条件下的蚯蚓避光应激行为,并结合光线辐射在蚯蚓粪多孔介质内的衰减规律分析了蚯蚓堆肥物料表层一定之内厚度无蚯蚓的原因。结果表明:光照强度10 lx时,蚯蚓不受光照影响;光照强度10~30 lx时,蚯蚓的避光反应显现;光照强度30~210 lx时,蚯蚓的避光应激程度随着光照强度增加缓慢加强,消失时间不断缩短;光照强度210 lx时,光照引起的蚯蚓的避光反应程度趋于最大。白光和太阳光引起蚯蚓避光反应最显著,蚯蚓蠕动消失时间分别为6.5和5 min,蚯蚓消失5 min后堆料表层无蚯蚓层厚度在10~15 mm之间。蚯蚓对红色光应激程度极低,平均消失时间20 min;除了红光,随着光照强度增加,蚯蚓在堆料表面的消失时间呈现对数曲线趋势下降。该研究量化分析了蚯蚓对光质、光照强度的应激响应时间,以期为蚯蚓养殖分离,机械自动化逐层、定时、定量、定光强分离表层蚯蚓粪提供工艺参数。 相似文献
10.
蛋鸡舍环境质量直接影响蛋鸡产蛋性能。为探究夏季蛋鸡舍环境质量及其对产蛋性能的影响,研究提出基于多元数据的分析方法,首先采集鸡舍内7类关键环境因子数据,按照热环境、光环境和气体环境分组,再根据改进D-S证据理论规则进行迭代融合,得到蛋鸡舍各检测点环境质量的综合评价结果,进而分析其对产蛋性能的影响。以夏季八层层叠式蛋鸡舍为试验鸡舍开展试验。结果显示：八层层叠式蛋鸡舍下四层的环境质量和平均产蛋率的最优位置均处于鸡舍前端;平均产蛋率最差的位置处于鸡舍中端,该位置环境质量综合评价结果为一般;上四层平均产蛋率最优位置为鸡舍中端,该位置环境质量综合评价结果为适宜;平均产蛋率最差位置和环境质量最差位置均为鸡舍后端（靠近风机端）。在试验鸡舍所有检测点中,平均产蛋率高于86%的检测点,环境质量综合评价结果大都为适宜,平均产蛋率低于86%的检测点,环境质量综合评价结果为一般或差,鸡舍内各检测点环境质量综合评价结果与平均产蛋率的变化趋势高度一致。该研究为准确评价蛋鸡舍环境质量,揭示蛋鸡舍环境质量对产蛋性能的影响提供了一种行之有效的方法。 相似文献
11.
选择45周龄体重接近的健康本地鸡441只,随机分为7组,在山西省太谷县生态养鸡场进行2(补饲量)×3(密度)两因子放养试验,研究林下种植苜蓿不同放养密度与补饲量对蛋鸡生产性能和蛋黄胆固醇含量的影响。补饲量设自由采食量50%、70%两个处理,密度为每667m2 100只、250只、400只3个处理,以笼养全程自由采食为对照,每组3个重复,每重复3个小区用于轮牧,小区面积为62 m2;预试期7 d,正试期70 d。结果表明:补饲量和放养密度互作对平均产蛋率影响极显著(P0.01),对蛋重和料蛋比影响不显著(P0.05)。笼养+自由采食组(CK)与补饲量70%、100只·667m-2组蛋重、平均产蛋率及料蛋比差异不显著(P0.05),但产蛋率显著高于其他各组(P0.05),蛋重显著高于补饲量50%、100只·667m-2组(P0.05),料蛋比显著低于补饲量50%组(P0.05)。补饲量和放养密度互作对蛋黄重、蛋黄胆固醇含量和全蛋胆固醇含量影响不显著(P0.05);放养密度对全蛋胆固醇含量影响极显著(P0.01)。笼养+自由采食组蛋黄重极显著高于补饲量50%、100只·667m-2组(P0.01),蛋黄胆固醇含量和全蛋胆固醇含量显著高于100只·667m-2组(P0.05)。补饲量70%下,100只·667m-2放养密度对牧草的破坏性小于其他放养密度。结合产蛋性能、蛋黄胆固醇含量以及草地保护,以70%补饲量+100只·667m-2组养殖模式较好,效果较佳。 相似文献
12.
Pan C Zhao Y Liao SF Chen F Qin S Wu X Zhou H Huang K 《Journal of agricultural and food chemistry》2011,59(21):11424-11431
A 35-day experiment was conducted to evaluate the effect of selenium-enriched probiotics (SP) on laying performance, egg quality, egg selenium (Se) content, and egg glutathione peroxidase (GPX) activity. Five hundred 58-week-old Rohman laying hens were randomly allotted to 5 dietary treatments of 100 each. Each treatment had 5 replicates, and each replicate had 5 cages with 4 hens per cage. The SP was supplemented to a corn-soybean-meal basal diet at 3 different levels that supplied total Se at 0.2, 0.5, and 1.0 mg/kg. The basal diet served as a blank control, while the basal diet with supplemental probiotics served as a probiotics control. The results showed that dietary SP supplementation not only increased (p < 0.05) the rate of egg laying, day egg weight, mean egg weight, egg Se content, and egg GPX activity but also decreased (p < 0.05) the feed:egg ratio and egg cholesterol content. The egg Se content was gradually increased (p < 0.05) along with the increasing level of dietary Se. The SP supplementation also slowed down (p < 0.05) the drop of Haugh units (HU) of eggs stored at room temperature. The egg GPX activity had a positive correlation (p < 0.01) with egg Se content and a negative correlation (p < 0.01) with egg HU drop. These results suggested that Se contents, GPX activity, and HU of eggs were affected by the dietary Se level, whereas the egg-laying performance and egg cholesterol content were affected by the dietary probiotics. It was concluded that this SP is an effective feed additive that combines the organic Se benefit for hen and human health with the probiotics benefit for laying hen production performance. It was also suggested that the eggs from hens fed this SP can serve as a nutraceutical food with high Se and low cholesterol contents for both healthy people and patients with hyperlipidemia, fatty liver, or cardiovascular disease. 相似文献
13.
Effect of selenium source and level in hen's diet on tissue selenium deposition and egg selenium concentrations 总被引：10，自引：0，他引：10
Pan C Huang K Zhao Y Qin S Chen F Hu Q 《Journal of agricultural and food chemistry》2007,55(3):1027-1032
The present study was conducted in a 2 x 4 factorial arrangement in a randomized complete block (RCB) design to compare the effects of a commercial inorganic Se source (sodium selenite, SS) with a commercial organic Se source (Se-enriched yeast, SY) on tissue Se distribution and blood and whole-egg Se concentrations in laying hens. Both Se sources were added into the basal diet at 0, 0.2, 0.5, and 1.0 mg/kg of Se. Seven hundred 68 week old Rohman laying hens were fed with a basal diet containing 0.15 mg/kg DM (dry matter) of Se for 2 weeks, and then, they were allocated randomly into seven groups and were investigated for 28 days. Each group was replicated five times with five cages of four hens per cage in each replicate. During the experiment, two eggs per replicate from each treatment were collected every 7 days and blood was sampled on days 0, 14, and 28 for whole-egg and whole-blood Se analyses. At the end of the experiment, two hens per replicate from each treatment were slaughtered, and muscle (cardiac and breast muscles), liver, spleen, and kidney were sampled for the determination of Se concentrations. The results showed that the addition of Se from either source caused a significant increase in whole-egg and whole-blood Se concentrations (p < 0.01) and Se concentrations in liver, kidney, spleen, and cardiac and breast muscles (p < 0.05) of hens in comparison to the control. Both Se sources and Se levels significantly influenced (p < 0.01) Se concentrations in egg, blood, and the above-mentioned tissues. There was a more significant increase in the Se concentrations in egg (p < 0.01), spleen (p < 0.05), and breast muscle (p < 0.01) and a decrease (p < 0.01) in whole-blood and kidney from hens fed SY than those from hens fed SS. The order of Se distribution was liver > kidney > spleen > cardiac muscle > egg > blood > breast muscle, irrespective of the addition level or source. It was concluded that meat and eggs from hens fed commercial SY are a potential source of Se for humans. 相似文献
14.
蛋鸡福利化养殖模式及技术装备研究进展 总被引：2，自引：6，他引：2
自1999年欧洲福利法提出全面禁止传统笼养以来,世界各国开展了很多蛋鸡福利化养殖系统的研究,以保障蛋鸡福利,取得了很多方面的改进。然而,在世界上的主要蛋品生产国家中,福利化养殖设施所占蛋鸡养殖模式的比例仍然较低。随着人们对动物福利的重视和行业的可持续发展要求的提高,开发新型养殖设施的呼声日益高涨。根据国内养殖业建筑现状以及现代高产品种抗病力差的特点,发展福利化养殖装备提高蛋鸡鸡体本身的健康和福利,减少因药物使用带来的负面影响,中国开发福利化蛋鸡养殖设施以提高鸡体健康和福利以抵抗疾病,减少用药;同时促进舍内环境良好,创造适应现代鸡群的生存条件显得至关重要。该文通过概述世界现存的几种替代传统笼养的福利化养殖模式及装备,比较它们各自的特点以及它们在蛋鸡福利、生产性能及蛋品质、社会经济环境对它们产生的不同影响等方面的差异。提出并分析了不同养殖系统存在的主要问题。通过总结国外蛋鸡福利化养殖设施的优缺点,为国内蛋鸡福利化系统的开发提供参考。在改善行为福利的同时,还需要结合传统笼养鸡体与粪便分离、动物健康状况好、投资较低的优点,改变现有的福利化养殖装备系统设计。另外,该文展望了福利化养殖设施的发展方向,并提出了发展福利化养殖设施的新思路。 相似文献
15.
Effect of dietary daidzein on egg production, shell quality, and gene expression of ER-alpha, GH-R, and IGF-IR in shell glands of laying hens 总被引：1，自引：0，他引：1
Ni Y Zhu Q Zhou Z Grossmann R Chen J Zhao R 《Journal of agricultural and food chemistry》2007,55(17):6997-7001
Our previous studies demonstrated that dietary daidzein improves egg production in ducks during the late period of the laying cycle. The present study was aimed to investigate the effect of daidzein in laying hens, with more focus on eggshell quality. The expression of ER-alpha, GH-R, and IGF-IR mRNA in shell glands was determined to identify the target genes of daidzein action and to reveal the relationship between shell quality and profiles of gene expression in shell glands of laying hens. 1000 ISA hens, at 445 days of age, were allotted at random to two groups and given the basal diet with or without 10 mg of daidzein per kg diet for 9 weeks. Daidzein supplement significantly increased the egg laying rate and the feed conversion ratio. The eggshell thickness increased, while the percentage of cracked eggs decreased in daidzein-treated hens. Serum E2 and phosphate concentrations were not altered, but the level of serum Ca2+ and the tibia bone mineral density were significantly increased in the daidzein-treated group compared with their control counterparts. In parallel with the significant increase of oviduct weight, significant down-regulation of GH-R and IGF-IR mRNA and a trend of decrease in ERalpha mRNA expression in shell glands were observed in daidzein-treated hens. The results indicate that dietary daidzein improves egg laying performance and eggshell quality during the late (postpeak) laying stage of hens, which is associated with modulations in gene expression in the shell gland. 相似文献
16.
McReynolds JL Caldwell DY McElroy AP Hargis BM Caldwell DJ 《Journal of agricultural and food chemistry》2000,48(12):6435-6438
Competitive exclusion (CE) cultures may offer alternatives to antimicrobial agents for disease prophylaxis in poultry. To avoid potential transfer of antibiotic resistance, safe and effective CE cultures must, by necessity, be highly sensitive to antimicrobial residues. The following studies evaluated the effect of maternal administration of selected antibiotics on the establishment of a licensed CE culture, PREEMPT. Selected antibiotics were administered to actively laying hens for a period of 7 days (experiment 1) or 9 days (experiment 2) in drinking water [sulfadimethoxine (0.05%), enrofloxacin (0.005%), and tylosin tartrate (0.05%)] or feed (sulfadimethoxine with ormetoprim, 250 ppm). In experiment 1, fertile eggs were collected daily and subjected to bioassay for detectable antimicrobial residues in yolk. Antimicrobial residues were not detected during the 7 days of treatment or the subsequent 3 days following cessation of treatment in the control, sulfadimethoxine, sulfadimethoxine with ormetoprim, or tylosin treatment groups. However, detectable residues were observed in eggs derived from enrofloxacin-treated hens on days 6 and 7 during antibiotic administration and also on days 2 and 3 post-antibiotic administration. In experiment 2, antimicrobial residues were also only detected in yolks from hens treated with enrofloxacin. Residue detection occurred on days 2-6 of antibiotic administration, on day 9 of antibiotic administration, on days 1-3 post-antibiotic administration, and also on day 7 post-antibiotic administration. A subset of eggs from each experimental group, corresponding to days 2-6 of antibiotic administration, days 4-6 post-antibiotic administration, and days 14-16 post-antibiotic administration, were pooled for incubation, and chicks hatched from these pools of fertile eggs were treated with PREEMPT at hatch. When 48-h cecal propionate concentrations were used as an index of culture establishment, reduced (P < 0.05) efficacy was observed only in chicks derived from enrofloxacin-treated hens at either collection period. Although several antibiotics do not appear to produce detectable egg residues or interfere with CE culture establishment, these data suggest that chicks derived from enrofloxacin-treated hens may not be candidates for safe and effective CE culture treatment. 相似文献
17.
为了分析不同饲养模式和阶段对蛋鸡发声的影响,并为构建基于蛋鸡声音信息的健康养殖评价系统提供参考,该研究对蛋鸡的发声进行了监测,通过声音预处理、特征提取、数据挖掘和统计分析等方法,研究笼养和栖架饲养模式下、育成期和产蛋期蛋鸡的声学特征。结果表明,典型蛋鸡声音可分为产蛋叫声、鸣唱声、鸣叫声和争斗尖叫声等四类。产蛋期蛋鸡发声的峰值频率和声音能量水平均低于育成期蛋鸡。同时发现蛋鸡发声的峰值频率与蛋鸡周龄大小呈现负相关关系,由14周龄的(2 192±320)Hz降至41周龄的(1 550±345)Hz。比较笼养和栖架养殖模式下蛋鸡的声音特征发现:栖架养殖模式下蛋鸡发出的声音信号次数、持续时间和声音能量均高于笼养模式,栖架养殖下的蛋鸡发声数量是笼养模式下蛋鸡的3倍以上,栖架系统内蛋鸡白天的声音能量比笼养蛋鸡高接近1倍,这些结果表明在以福利化为目标的栖架养殖模式中蛋鸡表达更多的自然行为,蛋鸡发声的丰富程度可用于后续开发评价蛋鸡的福利状况的方法。 相似文献
18.
Geuns JM Malheiros RD Moraes VM Decuypere EM Compernolle F Buyse JG 《Journal of agricultural and food chemistry》2003,51(4):1095-1101
In intubation experiments (643-1168 mg per animal), most of the stevioside administered to chickens was recovered unchanged in the excreta, and only about 2% was converted into steviol. Neither stevioside nor steviol could be found in the blood. In chronic studies (667 mg of stevioside/kg of feed) with laying hens and meat-type chickens, no significant differences were found in feed uptake, weight gain, and feed conversion as the result of stevioside administration. The egg production and egg composition of laying hens were not influenced. Most of the stevioside taken up was found untransformed in the excreta, and about 21.5% or 7.3% was converted to steviol by meat-type chickens or laying hens, respectively. No stevioside or steviol could be detected in the blood or in the eggs of the different groups of animals. In anaerobic incubation experiments with chicken excreta, only a 20% conversion of stevioside into steviol was found. No harmful effects were observed in the chronic stevioside supplementation experiments nor in the intubation experiments in which very high stevioside doses were given. 相似文献