不同水平的青贮饲料对饲喂稻草秸秆奶牛瘤胃微生物数量和微生物蛋白合成的影响

本试验的目的是确定饲粮中青贮银合欢添加水平对奶牛瘤胃微生物种群、氮平衡和微生物蛋白合成的影响。试验采用4×4拉丁方设计,选择12头初始体重为163±16 kg、带有瘤胃瘘管的奶牛,随机分为4个组,每组3个重复,每个重复1头牛。基础日粮以100%的水稻秸秆为原料,处理组分别用30%、60%和100%的青贮银合欢替代水稻秸秆,奶牛自由采食水稻秸秆和青贮银合欢,每天按照体重的0.2%补充浓缩料。结果表明,用60%青贮银合欢替代水稻秸秆组奶牛瘤胃微生物群,尤其是纤维素分解菌、蛋白分解菌和厌氧真菌的数量显著增加(P<0.05),各组对淀粉分解菌群无显著影响(P>0.05)。原生动物种群数量随日粮青贮银合欢添加水平的增加呈线性下降(P<0.05)(P<0.05)。此外,氮平衡和微生物蛋白合成均随着日粮青贮银合欢添加水平的升高而升高(P<0.05),其中以60%青贮银合欢组最高。结论:在本试验基础上,用60%青贮银合欢替代水稻秸秆可以显著提高奶牛体内的微生物数量和微生物蛋白的合成。     

鸡粪及其配施尿素对甜瓜香味物质、酶活性及基因表达的影响

为了探讨鸡粪以及鸡粪与尿素配施对薄皮甜瓜果实香气物质合成及关键酶的影响,以薄皮甜瓜"DX108"为试材,以尿素为氮源的处理作为对照(CK),研究等量氮素条件下,鸡粪及其与尿素配施处理对甜瓜果实香气物质以及相关酶活性变化的影响,并分析了乙醇脱氢酶(ADH)和醇酰基转移酶(AAT)基因的表达水平。结果表明:不同处理对薄皮甜瓜香气物质合成、相关酶活性以及关键酶基因表达的影响存在明显差异;尿素处理促进了甜瓜果实中C6和C9醇醛类化合物的合成,而鸡粪以及鸡粪与尿素配施提高了成熟果实中酯类物质含量和种类,尤其是乙酸酯类含量;鸡粪配施尿素处理提高了花后35 d甜瓜果实中非乙酸酯类物质含量,且是尿素处理花后35 d甜瓜果实中非乙酸酯类物质含量的3.1倍,还检测到了尿素处理果实中没有检测到的特征性酯类物质;鸡粪和鸡粪配施尿素处理提高了花后25～30 d果实中LOX酶、氨基转移酶、ADH酶以及AAT酶活性,降低了花后35 d果实中ADH酶活性,抑制了30 d后果实中CmADH1和ADH2的基因表达,而促进了CmAAT1和CmAAT3基因表达。由此可知,鸡粪以及鸡粪与尿素配施有可能是通过调节果实不同发育期香味物质合成途径中关键酶活性的协调变化以及关键酶基因表达,影响了果实香气物质的合成,尤其是酯类物质的合成。     

施用畜禽有机肥对辽河三角洲养蟹稻田水土环境的影响

经3 a的试验研究,探讨了施用畜禽有机肥对辽河三角洲养蟹稻田水土环境的影响。结果显示,畜禽有机肥可极显著地增加养蟹稻田耕层土壤的速效氮、磷、钾的供应量,显著增加有机质含量,最终显著增加水稻产量,增产的幅度可达10.6%~14.8%。畜禽有机肥可降低耕层土壤氧化还原电位(Eh),增大田面水体中BOD5、COD的含量,所以在生产应用中既要作好无害化处理、充分腐熟,还不能超量使用,否则会给河蟹带来生长迟缓、重金属含量超标和水稻病害加重及倒伏的风险。     

体外棕榈酸诱导自噬调节奶牛淋巴细胞炎症通路

为探讨体外棕榈酸(Palmitic acid,PA)是否可以通过自噬调节奶牛淋巴细胞炎症信号通路的激活,分离健康奶牛淋巴细胞,采用3-MA(3-Methyladenin,细胞自噬抑制剂)和不同质量浓度PA作用于淋巴细胞,收集细胞及上清,利用qRT-PCR检测淋巴细胞LC3B、Beclin1、mTOR、UKL1、SQSTM1、IL-1β、IL-6和TNF-αmRNA表达情况;利用CCK-8和酶联免疫吸附法分别测定细胞活性和促炎细胞因子TNF-α、IL-6和IL-1β的释放量。CCK-8结果表明:PA显著抑制淋巴细胞活性(P0.01),添加自噬抑制剂3-MA后细胞活性显著增强(P0.01);qRT-PCR结果表明:与对照组(PA=0μg/mL)相比,PA处理组(不含3-MA)ULK1和LC3B mRNA表达极显著增加(P0.01),mTOR、Beclin1和SQSTM1 mRNA表达极显著降低(P0.01);IL-1β和IL-6 mRNA表达显著增强(P0.01),而TNF-α未表达;添加3-MA后,与1μg/mL PA处理组相比较,SQSTM1和Beclin1极显著增加,而LC3B mRNA表达极显著降低(P0.01);IL-1β和IL-6 mRNA表达显著下调(P0.01);PA增加促炎因子IL-6和IL-1β的释放(P0.01),显著抑制TNF-α释放(P0.01),而含有3-MA的PA混合处理组则显著降低(P0.01)。综上,PA可通过自噬调节奶牛淋巴细胞炎症信号通路的激活。     

Cattle manure and inorganic nitrogen fertilizer application effects on soil hydraulic properties and maize yield of two soils of Murewa district,Zimbabwe

This study set out to determine the effects of cattle manure and inorganic N‐fertilizer application on the hydraulic properties and maize yield of a clay and sandy soil in a smallholder farming area of Zimbabwe. Four fields classified as homefields (HF: more fertile and closer to homesteads) and outfields (OF: less fertile and further from the homesteads) were selected on clay and sandy soil. They were subjected to four treatments, control (no fertility amendment), 5, 15 and 25 t/ha cattle manure + 100 kg/ha N (as ammonium nitrate) for 7 years. A two‐way randomized complete block design was used with fertility and field type as the two factors. Clay soil hydraulic properties, which included density of macropores with a diameter >300 μm, unsaturated hydraulic conductivity, steady‐state infiltration rate, moisture retention under low suction and maize grain yield, were significantly improved (P < 0.05) by fertility management compared with the control and were generally comparable between the HF and OF. Fertility management significantly improved maize grain yield on sandy soils but did not enhance hydraulic parameters, thereby indicating poor responsiveness in structural build‐up. On the other hand, significantly different hydraulic parameters between the sandy soil HF and OF suggested effects of other factors not related to soil fertility and field type treatments. We therefore concluded that application of a high rate (25 t/ha) of cattle manure and inorganic N‐fertilizer is beneficial for fertility restoration to the degraded OFs with associated comparable hydraulic properties on HFs and OFs on clay soil, unlike on sandy soil.     

鸡粪饲料资源开发利用现状

经济的发展和人们生活水平的不断提高,直接推动了养鸡业的发展。养鸡业的繁荣为人们提供了丰富的蛋肉产品,同时也产生了大量的废弃物,如鸡粪、垫料等,这些废弃物对生态环境造成了严重的影响。文章主要对鸡粪饲料资源开发利用现状进行论述。     

基于正交试验的花生种养结合栽培方式研究

种养结合是农业循环经济发展的重要措施之一。通过正交试验设计,分析了不同种植密度、复合肥用量、腐熟干粪用量对花生生长发育及产量的影响。分析结果表明:1)三因素中高钾复合肥用量对花生的生长发育及产量影响最大。2)13-10-20高钾复合肥用量为300kg/hm2的处理组合普遍表现出植株较高、分枝数较多、单株结果数多等特点。3)产量分析结果显示:最优处理组合为种植密度120 000穴/hm2、高钾复合肥300kg/hm2、腐熟干粪30kg/hm2,同时影响产量大小的因素顺序为:高钾复合肥腐熟干粪种植密度。     

Characterization of Aerococcus viridans isolated from milk samples from cows with mastitis and manure samples

Thirty-eight Aerococcus viridans isolates were obtained from milk from 478 cows with clinical mastitis in a farm during the periods between November 2011 and February 2012, and between December 2012 and March 2013. Additional isolates were obtained from processed manure (a mixture of composted manure, straw and hydrated lime) and bedding materials. The processed manure was later used to cover the floor of the stalls in barns as bedding materials. The temperatures recorded in the composted and processed manure were not as high as those generally observed during satisfactory composting. To reveal the association of A. viridans in manure-related products with intramammary infection in cows, isolates were characterized by their DNA fragment patterns as determined by pulsed-field gel electrophoresis (PFGE) and antimicrobial susceptibility testing. Isolates obtained from milk, processed manure and bedding materials had identical DNA fragment patterns. Antimicrobial susceptibilities were determined for 29 isolates from milk, processed manure and bedding materials. Of these, 26 (89.7%) were resistant to clindamycin, whereas virtually all the isolates were susceptible to 12 other antimicrobials including cefalosporins that have been used to treat bovine mastitis in Japan. In vitro, three A. viridans isolates from milk and an isolate from processed manure survived for 3 hr in Good’s buffer (pH 9) at high temperature (50°C). The results suggest that the processed manure and bedding materials in this farm were possible sources of A. viridans that caused infection in the cows with mastitis.     

Plasma fluctuation in estradiol-17β and bone resorption markers around parturition in dairy cows

Blood samples were obtained sequentially from 10 dairy cows around the time of parturition to assess plasma fluctuations in estradiol-17β (E₂) levels in association with those of several bone resorption markers. Plasma E₂ concentration increased sharply a few days prepartum and decreased quickly after parturition. In terms of bone resorption markers, the plasma level of tartrate-resistant acid phosphatase isoform 5b (TRAP5b) rose significantly, commencing 1 week prepartum, and was maintained at this level to a few days postpartum. The plasma concentration of carboxyterminal collagen cross-links of type-I collagen (CTx) increased significantly after parturition. These observations suggest that osteoclast-mediated bone resorption was activated after parturition when plasma E₂ concentrations decreased.