利用泰乐菌素菌渣生产复合酶制剂及效果研究

发酵法生产抗生素过程中会产生大量废弃菌渣,这些菌渣因有机质含量高,堆放极易发生霉变,给当地环境造成危害.文章采用固体发酵法,以微生物降解处理后的泰乐菌素菌渣为主要原料,生产复合酶制剂,并对其在肉鸡上的使用效果进行研究.结果表明:在水含量50％～60％、干物质中麸皮含量不低于40％的泰乐菌素菌渣培养基中,接入5％～10％...     

Comparative effect of thymol or its glucose conjugate,thymol-β-d-glucopyranoside,on Campylobacter in avian gut contents

Campylobacter jejuni is an important human food-borne pathogen that can contaminate meat and poultry during processing. Consequently, strategies are sought to reduce the carriage of C. jejuni in food animals before they arrive at the abattoir. Thymol is a natural product that reduces survivability of Campylobacter in vitro, but its rapid absorption from the proximal alimentary tract limits its bactericidal efficacy in vivo. Thymol-β-d-glucopyranoside is more resistant to absorption than free thymol, but its administration to chickens has not been reported. In the present studies, 1 mM thymol-β-d-glucopyranoside was shown to exhibit near equal anti-Campylobacter activity as 1 mM thymol when incubated anaerobically in avian crop or cecal contents in vitro, resulting in reductions of 1.10–2.32 log₁₀ colony forming units mL^?1 in C. jejuni concentrations after 24 h incubation. In a follow-up live animal study, oral administration of thymol-β-d-glucopyranoside, but not free thymol, significantly lowered (>10-fold) recovery of Campylobacter from the crop of market-aged broilers when compared to placebo-treated controls (n = 6 broilers/treatment). Neither thymol-β-d-glucopyranoside nor thymol affected recovery of Campylobacter from cecal contents of the treated broilers. These results indicate that rapid absorption or passage of free thymol from the crop precluded its anti-Campylobacter activity at this site and throughout the entire gastrointestinal tract. Conversely, lower recovery of Campylobacter from the crop of birds treated with thymol-β-d-glucopyranoside indicates this conjugate was retained and able to be hydrolyzed to biologically active free thymol at this site as intended, yet was not sufficiently protected to allow passage of efficacious amounts of the intact glycoside to the lower gut. Nevertheless, these results warrant further research to see if higher doses or encapsulation of thymol-β-d-glucopyranoside or similar glycosides may yield an efficacious additive to reduce carriage of Campylobacter as well as other pathogens throughout the avian gut.     

某集约化肉鸡饲养场PM2.5中抗生素抗性基因的分布特征

集约化家禽饲养场是抗生素抗性基因(ARGs)的重要来源,而PM_(2.5)作为ARGs可能向人体暴露的重要途径还未得到很好地研究.本文采集了集约化肉鸡饲养场舍内PM_(2.5)和粪便以及舍外PM_(2.5)样品,利用荧光定量PCR(q PCR)进行一类整合子(int I1)、总细菌(16S r DNA)和6类共19种ARGs丰度的检测.结果显示,除blaGES-1和blaSHV-1之外,其余17种ARGs在6类样品中均有检出.磺胺类、四环素类、大环内酯类和氨基糖苷类抗性基因在舍内粪便中丰度较高,达到1. 04×109～3. 27×1010copies·g-1,粪便是饲养场PM_(2.5)中ARGs的主要来源.舍内PM_(2.5)中以磺胺类和大环内酯类抗性基因丰度较高,分别为(8. 9±1. 9)×107copies·m-3和(5. 6±3. 1)×107copies·m-3,且舍内PM_(2.5)中ARGs丰度明显高于舍外. PM_(2.5)质量浓度与16S r DNA、int I1和ARGs丰度呈显著正相关,表明集约化饲养场中PM_(2.5)是空气传播细菌、ARGs和int I1的储存库和传播者. 6类样品中int I1丰度均高于ARGs,同时int I1和ARGs的共存关系表现出了多药耐药性的威胁,易对饲养人员和家禽健康及周边空气环境造成危害.     

丁酸钠对肉鸭生长及粪便中污染物减排效果的影响

在樱桃谷肉鸭的基础日粮中添加丁酸钠,研究了丁酸钠对肉鸭生产性能及粪便中污染物含量和排放量的影响.结果表明,添加350、700和1 050 mg·kg-1丁酸钠处理(试验组2、3、4)料重比较对照(试验组1)均显著降低,分别降低4.95%、6.71%和4.59%(P＜0.05),0～3周试验组3和4肉鸭日增质量较对照提高9.16%和9.47%(P＜0.05);添加丁酸钠可显著降低鸭粪中TN、TP、氨氮、有机质、Cu和Zn含量(P＜0.05),试验组3对TN、TP、氨氮和Zn的降低效果最好,分别较对照组减少6.15%、17.36%、59.98%和18.96%;不同水平丁酸钠处理鸭粪中污染物排放量均较对照显著降低(P＜0.05),试验组3对污染物TN、TP、氨氮、有机质和Zn的减排效果最好,而试验组4对Cu的减排效果最佳.在肉鸭饲料中添加700 mg·kg-1丁酸钠可获得最佳的生产性能和减排效果.     

笼养肉鸡舍冬季挥发性有机物排放特征

畜禽养殖过程产生的挥发性有机物（VOCs）会影响周围环境质量和人畜健康.针对肉鸡养殖过程挥发性有机物排放特征研究较少,主要致臭物质及致癌、非致癌健康风险影响评价不明确、臭氧生成潜力分析不足等问题,开展了对肉鸡舍内挥发性有机物的现场监测试验,在肉鸡舍采用苏玛罐采样结合气相色谱-质谱法分析了冬季肉鸡生长前期、生长中期和生长后期VOCs的排放特征.结果表明,肉鸡生长过程中共检测出77种VOCs,包括16种卤代烃、21种烷烃、5种烯烃、12种芳香烃、15种含氧VOCs （OVOCs）和8种含硫化合物.整个生长阶段舍内卤代烃、烷烃、烯烃、芳香烃和OVOCs浓度变化不大,但是随着肉鸡的生长,含硫氨基酸摄入量和粪便排污系数增加,舍内排放的VOCs逐渐转为硫化物为主.含硫VOCs浓度在生长前期和中期呈现不断升高趋势,但是生长后期舍内通风量增加导致含硫VOCs浓度降低.肉鸡生长过程中监测到的VOCs中主要致臭物质为萘、乙酸乙酯、乙醛、二硫化碳、二甲基二硫、甲硫醇、甲硫醚和噻吩,其中甲硫醇的恶臭指数最高,范围为2172.4~19090.9;生长前期和生长中期存在可能致癌健康风险,终生癌症风险（LCR）值分别为7.7×10^-6和4.5×10^-6.舍内VOCs臭氧生成潜势（OFP）平均值为（1458.9±787.4）μg ·m^-3.结果明确了肉鸡生长过程中VOCs的排放特征,摸清了致臭物质、健康风险和臭氧生成潜势,可为肉鸡养殖过程中污染气体减排策略的制定提供科学依据.     

Hematological responses of broiler chickens exposed to simulated crude petroleum emissions

Hematological responses of broiler chicken exposed to simulated crude petroleum emissions at varying distances over a period of 16 h daily were evaluated for 56 days in a poultry house. The burning of crude petroleum was simulated with a specially designed burner. The measured distances were 4, 8, or 12 m from the flame point. Control birds were located in a separate poultry building without the flame treatment. Gaseous emissions from the burning crude oil were monitored. Proprietory broiler starter and finisher diets were fed ad libitum. Blood samples were taken at the fourth and eighth weeks for hematological assay from each treatment. The hematological parameters assayed were hemoglobin (Hb), packed cell volume (PCV), white blood cells (WBC), neutrophils, and lymphocytes. Results indicated that the treatment did not significantly affect the Hb, PCV, and WBC constituents. Neutrophils significantly decreased while lymphocytes increased. The age of birds significantly increased Hb, PCV, and WBC levels in the blood.     

Hormonal responses of broiler chickens to simulated crude petroleum flame and fumes

Hormonal responses of broiler chickens exposed to crude petroleum flame and fumes at varying distances over a period of 16 h daily were evaluated for 56 days in a poultry house. The burning of crude petroleum was simulated in a designed burner. The measured distances were 4, 8, or 12 m from the flame point. The experimental design was a two-factor factorial in a completely randomized design (CRD) with factor A as distance from the crude petroleum flame and factor B was the age of birds in weeks. One hundred and eighty Anak day-old broiler chickens were divided into four groups of 45 birds each, replicated thrice at 15 birds per replicate. Control birds were located in a separate poultry building without the flame treatment. Gaseous emissions from the burning crude oil were monitored. Proprietary broiler starter and finisher diets were fed ad libitum. Blood samples were taken at the fourth and eighth week for hormone radioimmunoassay from each treatment. The hormones assayed were growth hormone (GH), thyroxine (T₄,), and adrenaline. Results indicated that treatments did not significantly alter hormonal levels. The age of birds significantly affected the levels of all three hormones measured.     

Supplementation of nitrocompounds in broiler diets: Effects on bird performance,ammonia volatilization and nitrogen retention in broiler manure

A study was conducted to evaluate the effects of dietary nitrocompounds on bird performance, ammonia volatilization, and changes in manure nitrogen (N). A total of 200 one-day-old male chicks (Cobb 500) were used for this study. The chicks were raised in electrically heated battery brooders for 18 days. On day 1, birds were allocated into five treatment groups with four replicated pens: (T1) control, a corn and soybean meal diet (3,100 kcal kg^?1 metabolizable energy (ME) and 21% Crude Protein (CP)); (T2) 16.7 mg kg^?1 nitroethanol (NEL); (T3) 33.3 mg kg^?1 NEL; (T4) 16.7 mg kg^?1 nitropropanol (NPL); and (T5) 33.3 mg kg^?1 NPL. The body weight gain, feed intake and feed efficiency were measured on days 7, 14 and 18. Volatized ammonia (VA) and other N forms were measured at collection and following 2 weeks of incubation at 30°C. Broiler growth was not adversely affected by the nitrocompounds at concentrations up to 33.3 mg kg^?1. The results show that initial manure pH was reduced by adding nitroethanol (NEL) and nitropropanol (NPL) to the diet by 0.2 and 0.5 pH units, respectively. Total VA after 2 weeks was unaffected by dietary treatment. The amounts of uric acid decomposed and ammonia produced were closely balanced in the control sample. However, this balance was significantly different among the manures produced by birds receiving nitrocompound treatments. The inclusion of NEL and NPL resulted in the presence of measurable amounts of Xanthine not found in the control group. This study indicates that supplementation of nitroethanol or nitropropanol into broiler diets up to 33.3 mg kg^?1 influences uric acid degradation and ammonia production in broiler manure while maintaining optimal growth performance.     

养鸡场空气中抗性基因和条件致病菌污染特征

集约化养殖场被认为是空气环境中抗性基因和致病菌的重要来源.本研究采集了养鸡场粪便和舍内外空气样本,对其抗生素抗性基因和条件致病菌的种类进行分析,包括五类抗生素(β-内酰胺类的23个基因、四环素23个基因、喹诺酮5个基因、磺胺类5个基因和红霉素2个基因)抗性基因、5种条件致病菌(肠球菌属、大肠杆菌属、葡萄球菌属、弯曲杆菌属和产气荚膜梭状芽胞杆菌属各1个基因)以及一类整合子(int I1)特异基因;并利用荧光定量PCR对检出率较高的典型基因浓度进行检测.结果显示,空气中5类抗生素抗性基因分别检出8、7、2、3和2个,同时检测到两种致病菌.目标基因在舍内空气中的检出率小于等于粪便样本.蛋鸡和肉鸡舍内空气中总细菌基因(16S r DNA)浓度为106copies·m-3,其他典型基因浓度约104copies·m-3,且在舍外的浓度要远低于舍内.抗生素抗性基因和条件致病菌基因在空气中所占比例高于粪便,舍内高于舍外.初步研究结果表明,粪便可能是舍内抗生素抗性基因、条件致病基因以及一类整合子的重要来源.本研究结果将为集约化养殖场抗生素抗性基因和致病菌的来源分析,以及养殖场对周边空气环境污染的风险评估提供基础数据.     

基于生命周期评价方法的肉鸡屠宰场碳足迹分析

当今世界畜牧业发展迅速,环境问题亦不可小视,由CO_2、CH_4和N_2O等温室气体导致的全球变暖是热门话题。基于PA-LCA方法追踪某肉鸡屠宰场的碳足迹,找出热点问题,再以敏感性分析探究全生命周期总碳足迹的最敏感输入变量,并提出碳减排建议,最后将运营期碳足迹与其他国家进行比较,为屠宰行业清洁生产和节能减排提供依据。结果表明:在建设期,商品混凝土、预拌砂浆和钢材的生产过程碳足迹分别占建设期总量的30.94%、24.77%和20.04%;在运营期,电力生产过程的碳足迹占运营期总量的93.06%,从企业各部门角度分析,屠宰间和冷库的运营产生48.45%的碳足迹;在报废期,拆除建筑所耗能源的生产过程碳足迹占报废期总量的87.13%。通过敏感性分析,工厂运营1年的电耗对屠宰场全生命周期碳足迹总量的影响不及建设期商品混凝土生产过程对其的影响,但运营10年后,运营期电耗减小可显著降低屠宰场全生命周期碳足迹。我国屠宰场运营期碳足迹同其他国家相比较低,这与我国屠宰自动化程度低有关。所以如何平衡屠宰效率和环境影响是亟待解决的问题。