两广小花猪(壹号黑猪)新品系选育进展

两广小花猪(壹号黑猪)新品系是以广东小耳花猪、陆川猪两个类群为育种素材,以繁殖性能为主,结合肉质、生长发育及外貌选择,经6年4个世代选育而成的高繁殖力新品系。为分析该品系毛色选育效果及其特性与利用价值,以该品系毛色选育提纯效果及各世代种猪生产性能测定数据为基础进行研究。结果表明,以MC1R基因作为遗传标记基因,结合表型选择,可逐渐纯化新品系群体;总产仔数与产活仔数,3世代初产母猪较0世代初产母猪分别提高1.05、0.72头(P>0.05),3世代经产母猪较0世代经产母猪分别提高0.75、0.76头(P<0.05);生长性状及胴体、肉质性状,3世代未发生较大变化。结论:两广小花猪(壹号黑猪)新品系提纯效果突出,繁殖性能得到明显地改善提高,且未对生长及胴体、肉质性状产生不利影响。该品系的培育为地方猪品种内的品系培育提供参考。     

日粮中添加发酵果渣对杜花二元杂交育肥猪生长性能和养分表观消化率的影响

本试验旨在研究发酵果渣对杜花二元杂交育肥猪的生长性能、养分表观消化率和饲料通过消化道时长的影响。选取480头80日龄左右、体况相近的杜花二元杂交育肥猪(♂杜洛克猪×♀广东小耳花猪),随机分为试验组和对照组,每组24个重复,每个重复10头猪。对照组饲喂基础日粮,试验组饲喂基础日粮的同时,按照猪生长阶段额外添加5%～20%的发酵果渣,饲养试验全期共5个月。结果显示,小猪阶段(25～60 kg阶段,添加5%～10%的发酵果渣),平均日增重无影响,试验组全价料采食量降低6.12%(P>0.05),料重比降低5.57%(P>0.05);中猪阶段(60～80 kg阶段,添加15%的发酵果渣),试验组平均日增重提高6.52%(P>0.05),全价料采食量降低7.55%(P>0.05,料重比降低12.90%(P<0.05);大猪阶段(80～100 kg阶段,添加20%的发酵果渣),试验组平均日增重提高4.69%(P>0.05),全价料采食量降低9.50%(P>0.05),料重比降低12.20%(P<0.05);试验全期,试验组平均日增重提高2.08%(P>0.05),全价料采食量降低7.47%(P>0.05),料重比降低8.62%(P<0.05)。额外添加发酵果渣能不同程度显著性提高杜花二元杂交育肥猪中后期对粗蛋白质的表观消化率,但对钙和磷的吸收具有降低的趋势。额外添加发酵果渣能缩短杜花二元杂交育肥猪前期饲料通过消化道的时长(P>0.05),但能不同程度延长中后期饲料通过消化道的时长(P>0.05)。本试验结果表明,在杜花二元杂交育肥猪日粮中额外添加适量的发酵果渣能提高生长性能,降低料重比,且可一定程度上延长饲料在育肥中后期猪消化道内的停留时间,促进猪对日粮中粗蛋白质等营养物质的消化吸收。     

从城市生态绿地系统建设探讨园林苗木生产

城市生态绿地系统的建设需应遵循生物多样性保护、地被性植物群落保护、乡土树种保护和自然环境修复的原则.在此原则指导下,对苗木的种类、形态、功能以及引种方面提出不同的要求,并指出苗木生产的发展方向和具体措施.     

加气灌溉下红壤土呼吸速率变化及其与土壤水氧的关系

加气灌溉技术是在地下滴灌的基础上发展起来的一种土壤通气增氧的新型灌溉方式,可以有效避免土壤含氧量低、通气性差给作物带来的危害.探明加气灌溉(AI)技术下红壤土呼吸速率变化规律与作用机理,为加气灌溉技术的推广提供理论依据.本研究基于中国热带农业科学院国家土壤质量湛江观测实验站,对比研究了加气灌溉与不加气灌溉处理下土壤呼吸...     

低盐度养殖池塘常见浮游微藻的种类组成、数量及优势种群变动

于2007年9月至2008年1月在广东珠海地区对低盐度养殖虾池水体的浮游微藻进行全程周期性调查分析.结果共检出常见浮游微藻5门31属49种,其中绿藻13属22种,蓝藻9属16种,硅藻6属8种,裸藻2属2种,隐藻1属1种.优势种有13种,主要是蓝藻,有铜绿微囊藻( Microcystis aeruginosa )、圆胞束球藻( Coelosphaerium naegelianum )、卷曲螺旋藻( Spirulina spirulinoides )、假鱼腥藻( Pseudoanabaena sp . )、绿色颤藻( Oscillatoria chlorine )、拟短形颤藻( Oscillatoria subbrevis )、粘连色球藻( Chroococcus cohaerens )、点状平裂藻( Merismopedia punctata )和针状蓝纤维藻( Dactylococcopsis aciculari ).其次是绿藻和硅藻,有蛋白核小球藻( Chlorella pyrenoidosa )、多粒衣藻( Chlamydomonas.multgranulis )、角毛藻( Chaetoceros sp . )和新月菱形藻( Nitzschia closterium ).低盐度虾池养殖周期浮游微藻细胞数量为0.1×10 7～209.2×10 7 ind·L -1,多样性指数平均为2.5～3.2.浮游藻类的种类数、数量及多样性指数总体表现为养殖前期低后期高的特征.     

Effects of miR-92a and miR-19b on insulin gene expression in mouse pancreatic β-cells

AIM To investigate the effect of microRNA-92a （miR-92a） and microRNA-19b （miR-19b） on the insulin expression in mouse pancreatic β-cells. METHODS The relative expression levels of endogenous miR-92a and miR-19b in mouse insulinoma MIN6 cells were detected by qPCR. The MIN6 cells were divided into control group， and experimental groups I and II， with 3 samples in each group， and transfected with negative control miRNA （NC）， miR-92a and miR-19b， respectively. The over-expression of the miRNAs was detected by qPCR. The morphological changes and viability of the cells were detected by optical microscopy and CCK8 assay， respectively. The expression of insulin was detected by qPCR， Western blot and immunofluorescence. The possible mechanisms of miR-92a and miR-19b regulating insulin expression were analyzed by bioinformatics prediction， dual-luciferase reporter assay， and Western blot. RESULTS Compared with the adult pancreatic progenitor cells， the expression of endogenous miR-92a and miR-19b in the MIN6 cells was decreased significantly （P<0.05）. Over-expression of miR-92a and miR-19b had no effect on the viability of MIN6 cells， but inhibited the expression of insulin at mRNA and protein levels. miR-19b significantly inhibited the luciferase activity of NeuroD1 3′UTR and the protein expression of NeuroD1 （P<0.05）. miR-92a had a fine-tuning effect on the luciferase activity of NeuroD1 3′UTR and the protein expression of NeuroD1. CONCLUSION miR-92a and miR-19b inhibit the insulin expression in mouse pancreatic β-cells.     

Injury pathways of hypoxia/reoxygenation in AC16 cardiomyocyte

AIM:To investigate the effects of hypoxia/reoxygenation (H/R) for different reoxygenation times on cardiomyocyte injury. METHODS:Human cardiomyocyte AC16 was cultured in glucose-free and serum-free DMEM with 1% O₂ for 24 h, 10% fetal bovine serum and low glucose DMEM combined with 21% O₂ were used to establish reoxygenation for 2 h, 6 h and 12 h, respectively. The cell viability was measured by CCK-8 assay. The protein levels of different cell injury pathway related molecules, such as LC3-Ⅱ/-I (autophagy), caspase-1 and gasdermin D (pyroptosis) and caspase-3 and Bax/Bcl2 (apoptosis), were determined by Western blot. RESULTS:Compared with blank control group, the cell viability in each H/R group was continuously decreased with the extension of reoxygenation time (P<0.05). The expression of LC3-Ⅱ/-I was up-regulated in hypoxia group and H/R group compared with blank control group (P<0.05). In addition, the protein levels of cleaved caspase-1 and cleaved gasdermin D were increased in H/R groups for 6 h and 12 h, respectively (P<0.05). Cleaved caspase-3 and Bax/Bcl2 were increased after reoxygenation for 12 h (P<0.05). CONCLUSION:Autophagy in hypoxia-induced AC16 cells is up-regulated, and then decreased by reoxygenation. The cell pyroptosis is activated earlier than the apoptosis during reoxygenation.     

广东小耳花猪仔猪初生重对其产房死亡率的影响

为研究广东小耳花猪仔猪初生重对哺乳期死亡率的影响,研究对两栋分娩舍内272头广东小耳花猪仔猪的初生重和死亡率进行了统计分析。结果表明:初生重低于等于0.4千克的仔猪死亡率高达81.25%,初生重在0.41耀0.6千克的仔猪死亡率为12%,当仔猪初生重大于0.8千克的时候死亡率仅为3.61%。初生重越大的仔猪,其死亡率呈现降低趋势并走向稳定。仔猪的死亡高峰期为出生后的8天内,64%的仔猪在该时期内死亡。死亡仔猪的主要原因为病弱和压死,两者总共占比为68%。此外,对两栋分娩舍进行对比发现,初生重越大的仔猪,其断奶重也越高。     

湛江市菠萝田间生产机械化需求分析与展望

菠萝种植是广东省湛江市徐闻县的传统特色产业,也是当地重要农业支柱产业之一。当前,菠萝生产除耕整地与茎叶处理环节外,种植、管理、收获等环节基本依赖人工,生产成本高,经济效益逐年降低,严重影响产业的健康发展。本文针对湛江市菠萝生产现状,以降低生产成本为目的,从提高生产效率、降低劳动强度的角度出发,以机械化技术为手段,提出适合湛江市菠萝生产实际、农机农艺相结合的菠萝机械化生产技术思路。     

枯草芽孢杆菌的培养条件及对水质的净化作用

研究了枯草芽孢杆菌(Bacillus subtilis Cohn,1872)(菌株编号:LB-B3)的培养条件及其在净化对虾养殖池水样方面的效果。实验分别设置了9个不同的pH值梯度(pH 2～10)和6个不同接种量梯度(0.3%、0.5%、1%、3%、5%和7%),以吸光值(OD)为生长指标,进行了枯草芽孢杆菌培养条件的优化实验;同时又设置了5个不同接种浓度(0 CFU/mL、5.2×104CFU/mL、1.04×105CFU/mL、1.56×105CFU/mL和2.08×105CFU/mL)接种待处理水样,测定了96 h内化学耗氧量、亚硝酸氮、氨态氮和溶氧等4个水质指标的变化情况。结果表明:pH=7.0、接种量为7.0%时,OD值最大;枯草芽孢杆菌能显著净化水质,但使用后会暂时性增加耗氧。