Influence of Low Light Irradiance on Grain Filling in Rice (Oryza saliva L.) cultivars

Time course of grain filling pattern in two rice (Oryza sativa L.) cultivars, grown under normal and low light intensities, was studied. The number of spikelets, partially filled grains and high density grains were monitored at a 5 day interval during grain filling period from uniform panicles tagged at anthesis. The low light tolerant cultivar Swarnaprabha had more high density grains and less partially filled grains throughout the grain filling period and at harvest compared to cultivar Ratna under both normal and low light intensities. Further, the opening of spikelets in two flushes in Swarnaprabha seemed to result in a more efficient resource allocation and hence better yield as compared to Ratna, in which the opening of spikelets was in a single flush on day 10.     

基于转录组的疏花软紫草低拷贝核基因引物开发

基于高通量的转录组测序,为大量并快速的开发分子标记提供契机。本研究对紫草科植物疏花软紫草进行转录组测序,共得到92042086条reads,从疏花软紫草158446个Unigene中搜索到332个低拷贝核基因。为进行多态性验证,从中随机挑选30个设计引物,并对3个疏花软紫草种群共9个个体进行PCR扩增,结果发现其中16对引物能够扩增出单一稳定的目的条带,从中随机挑选7个片段进行群体测序并计算DNA多态性。结果表明,7对引物的多态性位点平均值为657,单倍型平均值为514,单倍型多态性 （HD） 在0389~0944之间,核苷酸多态性 （Pi） 为000148~001723。通过转录组测序技术开发的低拷贝核基因有较高的多态性,且可以有效地运用于群体遗传学和谱系地理学研究中。另外,这些低拷贝核基因能够被运用于软紫草属植物系统发育重建以及物种形成等研究工作中。     

A highly sensitive,non‐invasive qPCR‐based strategy for direct quantification of Yersinia ruckeri in fish faeces

Finfish with asymptomatic Yersinia ruckeri infections pose a major risk as they can transmit the pathogen and cause clinical outbreaks in stock populations. Current tools have insufficient quantitative ability for accurately detecting the trace levels of Y. ruckeri typically associated with asymptomatic infection, necessitate invasive or lethal sampling, or require long processing times. This study presents a highly sensitive qPCR‐based method, targeting part of the Y. ruckeri 16S rRNA sequence, that is capable of detecting extremely low levels of Y. ruckeri in noninvasively collected faecal samples. Quantitative precision and accuracy of faecal sample analysis was consistent, despite the complexity of the faecal matrix. The assay demonstrated linearity over a six log‐wide dynamic range. Its limit of detection (LOD) and limit of quantification (LOQ) were 4 and 10 copies of the target sequence, respectively. Sensitivity of the assay was comparable to other qPCR‐based methods without requiring invasive or lethal sampling. Applicability as a screening strategy was tested using passively collected faecal samples. Asymptomatic Y. ruckeri infection was detected in all samples, although none of the fish exhibited overt infection. This method will be beneficial for finfish disease management if developed further as a noninvasive, screening tool against asymptomatic Y. ruckeri infection.     

Ostrich meat: Production,quality parameters,and nutritional comparison to other types of meats

The poultry industry is considered one of the most efficient industries in producing animal protein. Poultry production consists of several main segments: broilers, commercial eggs, turkeys, ducks, and other poultry, including geese, guinea-fowl, pheasants, quail, and ratites. Currently, ostrich meat is marketed as a healthy red meat because it is characterized by high polyunsaturated fatty acid contents, low saturated fatty acid content, and low cholesterol level compared with red meats, such as beef, while tasting similar to lean beef. Ostrich meat contains lower sodium and higher iron contents than other kinds of meat, making it preferable to hypertensive people and those with anemia. Taken together, ostrich meat is considered as an ideal red meat for individuals seeking healthier lifestyle. Moreover, many different ostrich products, such as leather and feathers, are used by people. The current review paper considers the quality characteristics of ostrich meat, including physical traits, and compares it to other types of meats, such as bovine and other poultry meats.     

Breeding distribution and maternal genetic lineages in Lulu,a dwarf cattle population in Nepal

Lulu is a dwarf cattle population bred in the Mustang district of western and central Nepal. This area is located around the habitat boundary between Bos taurus and Bos indicus. The peculiarities of Lulu are their small size (weight range in the adult female: 68–153 kg) and rearing in high mountain areas at 2800 m to 4000 m in altitude. There were 5770 head of Lulu cattle in the Mustang district in 1998, 4333 females and 1437 males. The morphological appearance of Lulu is Bos taurus. However, one of the five Lulu studied in Kagbeni, Mustang had a Bos indicus mitochondrial DNA type based on the D‐loop sequence, while the other four were Bos taurus. It is suggested that there are hybrids of Lulu with Bos indicus maternal lineage in a mostly taurine‐breed genetic background. Steps must be taken to preserve the unique Lulu.     

低温弱光对苗期紫花苜蓿根颈生理特性的影响

以秋眠级不同的2个紫花苜蓿Medicago sativa品种(巨人201和WL414)为试验材料,研究了其在低温(0~5℃和5~10℃)与弱光[50和100μmol/(m2.s)]互作处理条件下的生理响应。结果表明:紫花苜蓿根颈在低温弱光胁迫下启动了自身应激机制,对逆境胁迫做出了适应性反应,相同弱光条件下,低温0~5℃比5~10℃对根颈的影响显著,过氧化物酶活性上升幅度较小,而超氧化物歧化酶活性的下降和丙二醛含量的增加幅度均较大;相同低温处理,弱光50μmol/(m2.s)处理对根颈生理指标影响更为显著,过氧化物酶活性上升、超氧化物歧化酶活性下降和丙二醛含量增加幅度大于弱光100μmol/(m2.s)处理;巨人201各项指标的变化都优于WL414,表明巨人201抗寒耐弱光能力都可能优于WL414。     

低蛋白质对猪胴体品质的影响

本文综述了补充平衡氨基酸的低蛋白质日粮时于断奶仔猪及肥育猪的生产性能、胴体品质、脏器重量影响的研究,并分析了低蛋白质日粮对其生产性能和肉质影响的可能原因.     

低磷低鱼粉饲料中添加植酸酶和蛋白酶对草鱼生长性能和消化生理的影响

本试验旨在研究低磷低鱼粉饲料中添加植酸酶和蛋白酶对草鱼生长性能、消化酶活性、营养物质表观消化率和免疫力的影响。试验选取平均体重为9.66 g的健康草鱼630尾,随机分为7个组,每组3个重复,每个重复30尾鱼。7组草鱼饲喂如下试验饲料:正常磷(磷酸二氢钙添加量2.0%)正常鱼粉(鱼粉添加量3.0%)饲料(对照)、低磷(磷酸二氢钙添加量1.3%)正常鱼粉饲料、低磷正常鱼粉并添加0.03%植酸酶饲料、正常磷低鱼粉(鱼粉添加量1.5%)饲料、正常磷低鱼粉并添加0.05%蛋白酶饲料、低磷和低鱼粉饲料、低磷低鱼粉并添加0.03%植酸酶和0.05%蛋白酶饲料。饲养试验持续56 d。结果显示:与饲喂正常磷正常鱼粉饲料草鱼相比,饲喂低磷低鱼粉饲料草鱼的增重率、特定生长率、营养物质(干物质、蛋白质、钙和磷)表观消化率、肠道消化酶(胰蛋白酶、糜蛋白酶和淀粉酶)活性、血清溶菌酶活性均显著降低(P<0.05),饲料系数和血清丙二醛含量显著升高(P<0.05)。在低磷正常鱼粉饲料、正常磷低鱼粉饲料、低磷低鱼粉饲料中分别添加植酸酶、蛋白酶、植酸酶与蛋白酶后,草鱼的上述指标均得到显著改善(P<0.05)。以上结果表明,在低磷低鱼粉饲料中添加植酸酶和蛋白酶能够提高草鱼的营养物质表观消化率、肠道消化酶活性和免疫力,从而改善其生长性能。     

日粮能量和蛋白水平对双向选择血浆极低密度脂蛋白浓度肉鸡腹脂和产肉性能的影响

对７０８只（公母各半）５～９周龄一世代高、低极低密度脂蛋白（ＶＬＤＬ）系肉鸡进行３个代谢能水平（１３．４,１２．５,１１．６ＭＪ／ｋｇ）和３个粗蛋白水平（２２．４％,１９．４％,１６．４％）的三因子交叉的遗传－营养互作试验,以探讨肉鸡腹脂及屠体性状的遗传、营养、性别间的互作效应。结果表明：日粮对脂肪沉积的影响存在品系差异,品系与日粮代谢能互作对板油有明显影响（Ｐ＜０．０５）;日粮代谢能和粗蛋白对高ＶＬＤＬ系板油的影响大于低ＶＬＤＬ系,高ＶＬＤＬ系板油随日粮代谢能的升高而升高,而低ＶＬＤＬ系无此规律。品系与日粮代谢能互作对肌胃脂率有明显影响（Ｐ＜０．０５）,日粮代谢能对低ＶＬＤＬ系肌胃脂的影响大于高ＶＬＤＬ系,而粗蛋白对高ＶＬＤＬ系肌胃脂的影响大于低ＶＬＤＬ系。品系间肌胃脂的差异在不同日粮代谢能水平下表现不一致。品系与日粮互作对产肉性状未产生明显影响。日粮代谢能与性别间的互作对腿肌率有明显影响（Ｐ＜０．０５）,雌性腿肌率随代谢能水平的升高而降低。     

紫花苜蓿种子吸胀期胚根线粒体AsA-GSH循环对低温胁迫的响应

为探究胚根线粒体抗坏血酸-谷胱甘肽(AsA-GSH)循环响应低温胁迫的抗氧化作用机制,以紫花苜蓿种子为材料,研究了不同温度(10和20℃)处理下发芽特性、不同吸胀时间(6、12和24 h)胚根线粒体AsA-GSH循环酶活性、抗氧化物以及过氧化氢(H₂O₂)含量的变化规律。结果表明,吸胀12和24 h后,10℃处理的胚根线粒体H₂O₂含量高于20℃。吸胀24 h期间,10℃处理的胚根线粒体谷胱甘肽还原酶(GR)活性均低于20℃。吸胀12和24 h后,10℃处理的胚根线粒体抗坏血酸(AsA)含量均低于20℃。10℃条件下吸胀24 h后,与20℃处理相比,胚根线粒体谷胱甘肽(GSH)含量显著降低(P<0.05)。苜蓿种子在10℃条件下吸胀萌发时,主要通过降低AsA-GSH循环中GR、单脱氢抗坏血酸还原酶(MDHAR)、过氧化物酶(POD)活性和AsA、GSH含量,使胚根线粒体内的H₂O₂积累,产生氧化损伤,继而影响种子萌发的正常进程。