热应激条件下内毒素对肉鸡血常规指标的影响

采用复制肉鸡热应激病例模型的方法探讨肉鸡热应激机制。选用20日龄AA肉鸡50只,随机分为对照组(20只)和试验组(30只),适应性饲养2周后进行热应激处理,检测血清中内毒素含量及血常规指标的变化。结果显示:与对照组相比,热应激可以引起试验组血清中内毒素含量极显著升高(P<0.01);同时,血液中红细胞数目先升高后显著性降低(P<0.05);白细胞数目先降低后极显著性升高(P<0.01)。结果表明:肉鸡在热应激条件下内毒素含量的变化对机体产生了危害。     

一株凝结芽孢杆菌YNAU 5517对热应激肉鸡生长性能影响的初探

240只21日龄AA肉公鸡分成3个处理组,在22～42日龄阶段研究饲用凝结芽孢杆菌对热应激肉鸡生产性能的影响。对照组是非热应激处理组(Control,C);试验组1是热应激处理组(Heat Stress,HS),但不使用凝结芽孢杆菌;试验组2是热应激条件下使用凝结芽孢杆菌的处理组(Heat Stress+Bacillus coagulans YNAU 5517,HS-BC)。试验结果显示:与对照组肉鸡血清皮质酮浓度相比,试验组1升高了43.4%,差异显著(P<0.05);试验组2升高了19.5%,但差异不显著(P>0.05)。试验组2肉鸡血清皮质酮浓度比试验组1降低了16.7%,差异显著(P<0.05)。试验组1与试验组2肉鸡的平均日采食量及平均日增重统计差异不显著(P>0.05),均显著低于对照组(P<0.05)。饲料/增重比指标,试验组2比试验组1降低约3%(P>0.05),但均显著高于对照组(P<0.05)。干物质、粗蛋白、粗灰分等3个表观代谢率指标,三个处理组之间统计差异均不显著(P>0.05);其中试验组1和试验组2肉鸡对饲料粗脂肪的表观代谢率有高于对照组的趋势(0.050.05)。低密度脂蛋白胆固醇浓度指标,对照组最低、试验1组最高,且3个处理组之间统计差异均显著(P<0.05)。试验初步证明,凝结芽孢杆菌YNAU 5517能够一定程度的改善热应激肉鸡生产性能,直接效果是对料重比显示了积极的改善作用。     

复方中药对热应激肉鸡血液自由基影响的研究

将14日龄肉鸡60羽随机均分为3组:常温对照组、热应激对照组和试验组,试验组与热应激对照组饲养条件相同,试验组饲料中添加1%复方中药。3个组肉鸡定期采血,测定血清GSH-Px、SOD的活性和MDA的含量。结果表明:与正常对照组相比,热应激对照组肉鸡血清GSH-Px、SOD活性下降,MDA含量则上升,其中血清GSH-Px活性显著降低,MDA的含量显著增加(P<0.05)。结果表明,复方中药能提高正常肉鸡血清GSH-Px、SOD活性,降低MDA的含量,对抗热应激所致的肉鸡血清GSH-Px、SOD活性下降和MDA含量升高(P<0.05或P<0.01)。提示本复方中药具有较显著抗自由基损伤的作用,能有效地清除体内过多的自由基。     

应用延胡索酸、氯化铵缓解肉鸡热应激

夏季高温对笼养肉鸡的应激极为严重。以在饲料中添加0.1％延胡索酸和饮水中添加0.63％氯化铵(化学钝)作试验组,而对照组在饲料、饮水中均无添加物.且两组的基础日粮相同。试验表明,试验组肉鸡在高温下仍表现安静、骚动少,热喘息次数相应下降。而对照组肉鸡在同等高温下则表现极度不安、     

石菖蒲对热应激肉鸡生产性能和免疫功能的影响

本次试验研究石菖蒲对热应激肉鸡生产性能和免疫功能的影响。将80只14日龄AA肉雏鸡,随机分为4组,在热应激条件下,试验A组、B组和C组肉鸡分别灌服高(3mLl)、中(1.5mL)、低(1mL)三种剂量的石菖蒲水提液,连续7天,D组为对照组。在14日龄、21日龄、28日龄和35日龄分别计算饲料转化率,并采取外周血,计算IL-2含量。结果表明,石菖蒲能够明显提高热应激条件下肉鸡的饲料转化率(P<0.01),并能够提高热应激条件下肉鸡IL-2的含量(P<0.05)。说明石菖蒲具有效缓解热应激对肉鸡影响的作用。     

发酵中药对热应激817肉鸡生长性能、血清生化指标及抗氧化功能的影响

试验旨在研究发酵中药对热应激肉鸡生产性能、血清生化指标及抗氧化功能的影响。选取200只健康的15日龄817肉鸡，随机分为4组，每组5个重复，每个重复10只鸡。对照组和热应激组饲喂基础饲粮，2个试验组分别在基础饲粮基础上添加1%中药和1%发酵中药。预试期7 d，正试期18 d。正试期内，对照组肉鸡在舍温（26±1）℃、相对湿度55%～60%条件下饲养；热应激组、中药组和发酵中药组均进行热应激处理，3组环境温度（32±2）℃、相对湿度55%～60%。结果表明：试验期内，热应激组肉鸡的平均采食量（ADFI）、平均日增重（ADG）显著低于对照组，耗料增重比（F/G）显著高于对照组，1%发酵中药组肉鸡ADFI、ADG显著高于热应激组，1%中药组、1%发酵中药组肉鸡的F/G显著低于热应激组。热应激组的呼吸频率和直肠温度较其他3组显著升高，其中1%发酵中药组肉鸡显著低于1%中药组。热应激组肉鸡的血清谷丙转氨酶、谷草转氨酶、乳酸脱氢酶和肌酸激酶水平显著高于对照组和1%发酵中药组。与对照组和1%发酵中药组相比，热应激组肉鸡的血清甘油三酯和葡萄糖含量显著升高，总蛋白、球蛋白含量显著降低。与对照组和1%发酵...     

N-乙酰半胱氨酸对慢性热应激肉鸡肾脏功能损伤的缓解作用

为研究热应激对肉鸡肾脏功能的影响及N-乙酰半胱氨酸(NAC)的缓解作用,试验选择健康雏鸡60只,随机分为对照组、热应激组、热应激+NAC组,每组20只。对照组按照肉鸡饲养标准饲养,热应激组、热应激+NAC组模拟热应激环境,分别饮用自来水和0.2%的NAC水溶液,于28,35日龄时分别测定血清中尿酸、肌酐、尿素含量。结果表明:与对照组比较,28,35日龄时热应激组肉鸡血清尿酸、肌酐、尿素含量均显著或极显著升高(P0.05或P0.01);与热应激组比较,热应激+NAC组肉鸡血清尿酸、肌酐、尿素含量均显著或极显著下降(P0.05或P0.01)。说明饮水中添加0.2%NAC可有效缓解热应激状态下肉鸡肾脏功能的损伤。     

甜菜碱对热应激肉鸡生长性能、十二指肠消化酶活性及盲肠微生物区系的影响

本试验通过在饲粮中添加不同剂量的甜菜碱研究其对热应激肉鸡生长性能、十二指肠消化酶活性及盲肠微生物区系的影响。选取270只14日龄爱拔益加(AA)肉鸡随机分成6组:常温组、热应激组,常温+0.1%甜菜碱组、热应激+0.1%甜菜碱组、热应激+0.2%甜菜碱、热应激+0.4%甜菜碱组。热应激肉鸡饲养在(32±1)℃的高温环境中。每组3个重复,每个重复15只。预试期7 d,正试期21 d。结果表明:1)饲粮添加甜菜碱可极显著增加28~42日龄热应激肉鸡的体重(P<0.01),极显著降低22~35日龄肉鸡料重比(P<0.01);2)除添加0.1%和0.2%甜菜碱饲粮对28日龄热应激肉鸡胰蛋白酶活性无显著影响(P>0.05)和添加0.1%甜菜碱对35日龄热应激肉鸡淀粉酶活性无显著影响(P>0.05)外,不同浓度的甜菜碱均能显著或极显著增加28、35、42日龄热应激肉鸡十二指肠胰蛋白酶、淀粉酶和胰脂肪酶活性(P<0.05或P<0.01);3)饲粮添加甜菜碱极显著提高了28、35、42日龄热应激肉鸡盲肠内乳酸杆菌的数量(P<0.01),极显著降低了产气荚膜梭菌的数量(P<0.01)。由此可见,热应激状态下,在基础饲粮中添加甜菜碱可改善AA肉鸡生长性能,提高十二指肠消化酶的活性,维持盲肠内微生物区系平衡,从而减轻热应激对肉鸡的危害。     

谷氨酰胺对热应激肉鸡生长性能和血清生化指标的影响

为研究不同添加水平谷氨酰胺对热应激肉鸡生长性能和血液生化指标的影响,选用1日龄AA肉鸡240只,随机分为6个处理,每处理4个重复,每重复10R,Ⅰ组为对照组,饲喂玉米-豆粕型基础日粮,Ⅱ、Ⅲ、Ⅳ、Ⅴ和Ⅵ组为试验组,分别在基础日粮中添加0.4%、0.8%、1.2%、1.6%和20%的谷氨酰胺,试验时间15～42日龄,共28d.结果表明:日粮中添加谷氨酰胺对29～42日龄肉鸡生长性能有显著影响(P<0.05),其中以1.2%谷氨酰胺添加量的促生长效果最佳,但对15～28日龄肉鸡生长性能的影响不显著(P>0.05).日粮中添加谷氨酰胺对28日龄肉鸡血液生化指标有显著影响(P<0.05),其中0.8%谷氨酰胺组显著提高了热应激肉鸡血清总蛋白含量(P<0.05),1.6%谷氨酰胺极显著降低了热应激肉鸡血清尿素氮含量(P<0.01);添加1.2%谷氨酰胺极显著降低了42日龄热应激肉鸡血清尿素氮含量(P<0.01),但对总蛋白和葡萄糖的含量影响不显著(P>0.05).因此,在基础日粮中添加一定水平的谷氨酰胺可改善热应激肉鸡的生产性能和血清生化指标.     

热应激降低肉鸡小肠消化酶活性的研究

以艾维茵肉鸡为实验对象 ,研究了热应激对肉鸡消化酶活性的影响。结果显示 ,在热应激条件下 ,肉鸡小肠内总蛋白水解酶活性、脂肪酶活性和淀粉酶活性均显著下降。平均日增重与消化酶活性呈极显著正相关。表明消化酶活性下降是应激导致生产性能下降的重要原因     

铬对热应激下蛋鸡脾组织结构的影响

将处于热应激条件下的 192只 35周龄新罗曼褐壳蛋鸡随机分成 6组 ,分别饲喂不添加铬的玉米 -豆粕型基础日粮和添加 10、2 0、30、4 0、5 0 mg/ kg葡萄糖耐量因子 (glucose tolerance factor,GTF)的试验日粮 5 2 d。取出器官组织固定后 ,制作石蜡切片 ,HE染色 ,光镜观察。观察可见 ,添加 2 0 mg/ kg GTF组蛋鸡脾白髓中脾小结体积增大 ,生发中心明显 ;空肠管壁出现集合淋巴小结。添加 30、4 0 mg/ kg GTF组蛋鸡脾白髓动脉周围淋巴鞘增厚 ;椭球数量增多 ,体积增大。结果显示 :给热应激下蛋鸡补充有机铬 (GTF) ,免疫器官 (脾 )的组织结构发生明显变化 ,可缓解热应激反应 ,增强机体免疫功能     

补铬对热应激蛋鸡肾上腺组织结构的影响

试验选择处于热应激条件下的192只35周龄新罗曼褐壳蛋鸡,随机分为6组,分别饲喂添加0.10,20,30,40,50 g/t含铬量为7.410mg/kg的葡萄糖耐量因子(GTF)的玉米—豆粕型基础日粮52d。试验结束时随机抽取试验鸡36只(每组6只),取肾上腺称重并制作切片,研究有机铬对热应激蛋鸡肾上腺组织结构的影响。结果试验组肾上腺重量较对照组略有增加;热应激时蛋鸡肾上腺的肾间组织比例增大,肾间组织和嗜铬组织的细胞均有结构受损的现象;补铬使肾间组织比例减小,嗜铬细胞增多,细胞结构完好。     

铬对热应激下蛋鸡空肠组织结构的影响

将处于热应激条件下的 1 92只 35周龄新罗曼褐壳蛋鸡随机分为 6组 ,分别用玉米 豆粕型基础饲粮和添加 1 0 ,2 0 ,30 ,40 ,50g/t含铬量为7 41 0mg/kg的葡萄糖耐量因子 (GTF)的试验饲粮饲喂 52d。试验结束时取试验鸡 36只 ,每组 6只 ,取空肠制作切片观察组织结构。结果试验组空肠绒毛和肠腺的长度与对照组相比均增长 ,肠壁中有大量弥散淋巴组织和淋巴集结。其中添加 50g/t组的肠绒毛与对照组相比差异极显著 ,添加 2 0g/t组的肠腺与对照组相比差异极显著。表明补铬使热应激下蛋鸡空肠绒毛、肠腺的长度增加 ,淋巴组织发达。可以改善消化管的组织结构 ,增强机体的消化和免疫功能 ,具有缓解高温热应激反应的作用     

Effects of dietary betaine on growth performance,fat deposition and serum lipids in broilers subjected to chronic heat stress

We evaluated the effects of supplementing betaine on growth performance, fat deposition and lipid metabolism status in broilers kept under chronic heat stress. Five hundred and forty chicks were randomly divided into six groups and the two normal temperature groups were held at normal ambient temperature and fed the basal diet (CONT) and basal diet plus 0.1% betaine, respectively. Heat stressed (HS) broilers were held at 32 ± 1°C from days 22 to 42 and fed the basal diet containing variable levels of betaine. Broilers were examined at days 28, 35 and 42 for body weight, feed consumption, fat deposition and serum lipids. The CONT and betaine‐supplemented groups showed higher (P < 0.01 or P < 0.05) feed consumption, body weight gain, and lower feed : gain ratio compared with the HS‐CONT group. Meanwhile, heat stress increased abdominal, intermuscular and subcutaneous fat deposition, whereas the supplemental betaine significantly decreased those compared with the HS‐CONT group. Additionally, betaine supplementation significantly decreased triglyceride, free fatty acids, low‐density lipoprotein cholesterol and high‐density lipoprotein cholesterol compared with HS‐CONT. Chronic HS reduces broiler production performance. However, betaine can reverse these negative effects partially and thus improve carcass composition by changing lipid metabolism.     

Dietary supplementation of Zingiber officinale and Zingiber zerumbet to heat‐stressed broiler chickens and its effect on heat shock protein 70 expression,blood parameters and body temperature

The present study was conducted to assess the effects of dietary supplementation of Zingiber officinale and Zingiber zerumbet and to heat‐stressed broiler chickens on heat shock protein (HSP) 70 density, plasma corticosterone concentration (CORT), heterophil to lymphocyte ratio (HLR) and body temperature. Beginning from day 28, chicks were divided into five dietary groups: (i) basal diet (control), (ii) basal diet +1%Z. zerumbet powder (ZZ1%), (iii) basal diet +2%Z. zerumbet powder (ZZ2%), (iv) basal diet +1%Z. officinale powder (ZO1%) and (v) basal diet +2%Z. officinale powder (ZO2%). From day 35–42, heat stress was induced by exposing birds to 38 ± 1 °C and 80% RH for 2 h/day. Irrespective of diet, heat challenge elevated HSP70 expression, CORT and HLR on day 42. On day 42, following heat challenge, the ZZ1% birds showed lower body temperatures than those of control, ZO1% and ZO2%. Neither CORT nor HLR was significantly affected by diet. The ZO2% and ZZ2% diets enhanced HSP70 expression when compared to the control groups. We concluded that dietary supplementation of Z. officinale and Z. zerumbet powder may induce HSP70 reaction in broiler chickens exposed to heat stress.     

Vitamin E and organic selenium enhances the antioxidative status and quality of chicken semen under high ambient temperature

1. The effects of supplemental dietary vitamin E and organic selenium (Se), and their combination, on improving semen quality characteristics and antioxidative status were investigated in cockerels exposed to high ambient temperature.

2. A total of 36 Egyptian local cross males, 40 weeks old, were housed individually in cages in an open-sided building (average daily temperature ranged from 33 to 36°C and relative humidity from 60 to 70%). Birds were divided randomly into 4 experimental treatments (n?=?9 each): (1) control (basal diet without any supplementation with vitamin E or Se); (2) vitamin E (basal diet +200?mg α-tocopherol acetate/kg diet); (3) Se (basal diet +0·3?mg organic Se/kg diet); and (4) vitamin E?+?Se (basal diet +200?mg α-tocopherol acetate/kg diet +0·3?mg organic Se/kg diet).

3. Under heat stress conditions, inclusion of vitamin E and/or organic Se in the diets enhanced the semen quality traits, including the spermatozoa count and motility, and reduced the percentage of dead spermatozoa.

4. A combination of 200?mg/kg vitamin E with 0·3?mg/kg organic Se reduced the thiobarbituric acid reactive substance concentration in seminal plasma samples to about 28% of the controls; and also enhanced the seminal plasma glutathione peroxidase activity by two-fold compared with controls.

5. It was concluded that dietary vitamin E in combination with organic Se has a synergistic effect in minimising lipid peroxidation and improving the antioxidative status in seminal plasma of the domestic fowl, which probably translated into enhanced spermatozoa count, motility and reduced percentage of dead spermatozoa under heat stress conditions.     

日粮铬水平对热应激种公鸡睾丸组织结构及血浆生殖激素的影响

选择72只35周龄罗曼褐种公鸡,随机分为6组,每组12只,对照组饲喂基础日粮,分别在基础日粮中添加0．2、0．4、0．6、0．8、1．0mg／kg铬量的酵母铬,作为试验Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅴ组,来探讨日粮铬水平对热应激种公鸡睾丸组织结构及血浆生殖激素的影响。结果表明,在热应激条件下,给种公鸡日粮中添加0．8～1．0mg／kg铬量的酵母铬可有效缓解热应激对种公鸡睾丸生精机能的抑制作用,提高种公鸡血浆睾酮（T）、促黄体素（LH）和促卵泡素（FSH）的含量。     

有机铬对热应激蛋鸡生产性能和血液生化指标的影响

试验选用91周龄新罗曼商品蛋鸡480只,按2×2双因子试验设计随机分为5组,对照组饲喂不添加铬的玉米-豆粕型基础日粮,4个试验组饲喂在基础日粮中分别添加了以吡啶羧酸铬或酵母铬来源的0.2mg/kg或0.4mg/kg的日粮,试验30d,以研究有机铬对热应激蛋鸡生产性能和血液生化指标的影响。试验结果显示:①有机铬能在一定程度上促进热应激蛋鸡的蛋白质利用,提高热应激蛋鸡的生产性能;②铬水平对血清尿素氮有极显著的影响(P<0.01),添加0.4mg/kg铬组均极显著地低于对照组(P<0.01),说明了补铬能够抑制由高温引起的蛋白质分解过程,从而起到缓解高温应激的作用;③吡啶羧酸铬和酵母铬在作用效果上无显著的差异;从经济效益方面考虑,0.4mg/kg铬水平的酵母铬和吡啶羧酸铬经济效益较高。     

过瘤胃葡萄糖和缓释尿素对热应激绵羊生产性能及瘤胃发酵功能的影响

【目的】 本试验旨在研究饲粮中添加缓释尿素（SRU）和过瘤胃葡萄糖（RPG）对热应激绵羊生产性能和瘤胃发酵功能的影响。【方法】 选取40只健康、体重相近的3月龄湖羊公羔,按初始体重随机分成4个处理组（n=10）,分别为对照组（CON组,饲喂基础饲粮）、缓释尿素组（SRU组,基础饲粮中添加缓释尿素15 g/d）、过瘤胃葡萄糖组（RPG组,基础饲粮中添加过瘤胃葡萄糖10 g/d）和联合添加组（UG组,基础饲粮中添加缓释尿素15 g/d+过瘤胃葡萄糖10 g/d）,预饲期15 d,正饲期50 d。在正饲期的最后一天晨饲前,分别采集血液和瘤胃液,测定血样中免疫球蛋白A （IgA）、免疫球蛋白M （IgM）、免疫球蛋白G （IgG）、肿瘤坏死因子-α（TNF-α）、白细胞介素-2（IL-2）的含量,并测定瘤胃液pH、氨态氮、微生物蛋白及挥发性脂肪酸等指标。【结果】 与CON组相比,①饲粮中添加缓释尿素、过瘤胃葡萄糖均显著降低热应激绵羊的呼吸频率（P<0.05）,UG组热应激绵羊的直肠温度显著降低（P<0.05）。②SRU组、RPG组、UG组热应激绵羊的终末体重和平均日增重均显著提高（P<0.05）,料重比显著降低（P<0.05）。③RPG组和UG组热应激绵羊血清中IgG和IgM的含量均显著提高（P<0.05）,血清中TNF-α和IL-2的含量显著降低（P<0.05）。④各处理组热应激绵羊瘤胃内乙酸与丙酸的比值均显著提高（P<0.05）,SRU组瘤胃内乙酸、异丁酸、异戊酸比例和总挥发性脂肪酸的浓度均显著提高（P<0.05）,RPG组瘤胃液pH和异戊酸比例均显著提高（P<0.05）,瘤胃内氨态氮、丙酸、丁酸的比例均显著降低（P<0.05）,UG组瘤胃内乙酸、总挥发性脂肪酸及微生物蛋白的含量均显著提高（P<0.05）。【结论】 饲粮中添加缓释尿素、过瘤胃葡萄糖显著提高了热应激绵羊的生产性能,改善瘤胃发酵,维持瘤胃内环境的稳定,可有效缓解绵羊热应激。     

The effect of Epigallocatechin‐3‐gallate on small intestinal morphology,antioxidant capacity and anti‐inflammatory effect in heat‐stressed broilers

This study was to investigate the effects of Epigallocatechin‐3‐gallate (EGCG) on intestinal morphology, antioxidant capacity and anti‐inflammatory response in heat‐stressed broiler. A total of 192 2‐week‐old Arbour Acres broilers chickens were divided into four groups with six replicates per group and eight chickens per replicate: one thermoneutral control group (28°C, group TN), which was fed the basal diet; and three cyclic high‐temperature groups (35°C from 7:00 to 19:00 hr; 28°C from 19:00 hr to 7:00 hr, heat stress group), which were fed the basal diet supplementation with EGCG 0 mg/kg (group HS0), 300 mg/kg (group HS300) and 600 mg/kg (group HS600). The gut morphology and intestinal mucosal oxidative stress indicators, as well as intestinal barrier‐related gene expression, were analysed. The results showed that compared with group TN, heat stress reduced the villus height (VH), activities of glutathione peroxidase (GSH‐Px), superoxide dismutase (SOD)and catalase (CAT), increased the crypt depth (CD) and malondialdehyde (MDA)content at 21, 28 and 35 days (p < 0.05). After the heat‐stressed broilers were supplemented with EGCG, VH, VH/CD (V/C), and the activities of GSH‐Px, SOD and CAT were increased, and CD and MDA content were reduced compared with those in group HS0 without EGCG supplementation at 21, 28 and 35 days (p < 0.05). The EGCG supplementation promoted the gene expression of nuclear factor‐erythroid 2‐related factor 2 (Nrf2), Claudin‐1, Mucin 2 (Muc2) and alleviated the nuclear factor‐kappa B (NF‐κB) and lipopolysaccharide‐induced tumour necrosis factor (LITAF) gene expression compared with group HS0 (p < 0.05). Moreover, intestinal morphology was strongly correlated with antioxidant ability and inflammatory response. In conclusion, EGCG alleviated the gut oxidative injury of heat‐stressed broilers by enhancing antioxidant capacity and inhibiting inflammatory response.