计算机视觉技术在智慧羊场中的研究进展

智慧羊场具有科学化、标准化管理的优点,是羊场转型发展的趋势.计算机视觉技术是人工智能的核心,可以实现非接触性、自动化、实时监测羊的个体信息.本文总结并分析了计算机视觉在羊场的个体识别方法、行为识别方法、体尺与体重估测、疾病监测的研究现状,并指出计算机视觉在智慧羊场的进一步发展趋势.     

2013年中国农产品贸易发展特点及展望

2013年中国农产品贸易总额持续增长,进口增速首次在入世后低于出口增速。进口方面,继续保持增长但增速回落,国内外价差和国内供需缺口仍是大宗农产品进口持续高位的主要原因。出口方面,蔬菜和水产品等优势产品出口恢复增长,水果出口增速放缓。预计2014年中国农产品进口激增态势将得到缓解,但在价差的作用下进口压力仍较大,进口额增速可能恢复到两位数;出口形势有望好转,但增速相对缓慢。由于进口基数较大且仍快速增长,预计农产品贸易逆差将进一步扩大。     

如何检疫上市白条鸡

在上市白条 鸡中，经常碰到 掺杂的病死鸡、 注水鸡，如何检 验，现介绍如下： １看皮肤看 翅膀内侧，健康 鸡宰后毛孔闭 合，脱毛干净，皮 肤完整，平滑细 腻，色泽鲜艳，粉 红色或白色，有 光泽，有弹性，翅 内侧血管不显露；如脱毛不净，皮肤破损，呈紫红色而无光泽，毛囊出血，翅内血管显露清晰，则是死鸡或急宰放血不良的病死鸡。２看放血刀口正常宰杀鸡喉部放血不整齐，血液侵染较深；如无放血刀口或有刀口其切面平直，又无血液浸染，是死鸡或死后又拉一刀。３看头部健康鸡宰后鸡头洁净，鸡冠和肉髯呈玫瑰色，眼有光泽微闭合，若鸡头…     

Identification and characterization of IgA1 protease from Streptococcus suis

Streptococcus suis (S. suis) is a major swine pathogen and an emerging zoonotic agent. However, the current understanding of the S. suis pathogenesis of infection remains limited. In the present study, an IgA1 protease of S. suis was identified for the first time. The protein was recombinantly expressed in Escherichia coli, and the purified recombinant protein showed good cleaving reactivity to IgA1 and was highly immunoreactive to convalescent sera. The gene was found to exist in most pathogenic strains but scarcely in non-invasive isolates. These findings suggested that the IgA1 protease might play an important role in the pathogenesis of S. suis.     

Molecular cloning,sequence characterization,and expression analysis of C-type lectin (CTL) and ER-Golgi intermediate compartment 53-kDa protein (ERGIC-53) homologs from the freshwater prawn,Macrobrachium rosenbergii

Aquaculture International - Lectin protein families are diverse and multi-functional in crustaceans. The carbohydrate-binding domains (CRDs) of lectins recognize the molecular patterns associated...     

Effects of feeding levels on growth performance,feed utilization,body composition and apparent digestibility coefficients of nutrients for juvenile Chinese sucker,Myxocyprinus asiaticus

An experiment was conducted to determine effects of feeding levels on growth performance, feed utilization, nutrient deposition, body composition and apparent digestibility coefficients (ADCs) of nutrients for juvenile Chinese sucker (initial weight, 11.77±0.22 g). Chinese sucker were fed a practical diet from 0% (starvation) to 4.0% (at 0.5% increments) body weight (bw) day^?1 for 8 weeks. The results showed that growth performance, feed utilization, nutrient deposition, body composition and ADCs of dry matter, protein and energy were significantly (P<0.05) affected by feeding levels. Survival was the lowest for the starvation group. Final mean body weight, growth rate, thermal‐unit growth coefficient (TGC) increased with feeding rate from 0% to 3.0% bw day^?1 (P<0.05) and showed no significant differences above the level (P>0.05). Feed conversion rate was significantly lower at a feeding level of 2.5% bw day^?1 than above and below the level (P<0.05). Protein efficiency ratio was markedly highest at the 2.5% bw day^?1 ration level (P<0.05). Fish fed at the feeding level (1.0% bw day^?1), which represented a maintenance ration (energy gain was less than 2.27 kJ fish^?1 day^?1), showed positive protein deposition but negative lipid deposition. This indicates that fish fed a maintenance ration mobilize body lipid reserve to support protein deposition. Lipid contents of whole body, muscle and liver increased with increasing feeding rates from 0.5% to 3.0% bw day^?1 and showed no significant differences above the level (P>0.05). Protein contents of whole‐body composition increased with feeding rate from 0.5 to 3.0% bw day^?1 (P<0.05) and showed no significant differences above the level (P>0.05), whereas muscle and liver remained relatively stable with the different ration amount with the exception of fish fed a ration of 0.5% bw day^?1, at which Chinese sucker possessed significantly lower body protein concentration (P<0.05). The ADCs of dry matter, protein and energy decreased with increasing feeding levels from 0.5% to 3.0% bw day^?1 and then remained relatively constant over the level. Based on the broken‐line regression analysis using WG data, the optimum and maintenance feeding levels for Chinese sucker were 3.10% bw day^?1 and 0.45% bw day^?1 respectively.     

水丰水库渔获变化和鱼类资源现状及小型经济鱼虾种间关系分析

水丰水库的渔获量1961－1980年间变化于47－300t,1981-1984年增长到740－1321t,1985-2000年为2270－4926t。渔获物组成中以亚洲公鱼为主，1980－2000年亚洲蚣鱼占总渔获的29．6％－93．0％，平均为65．6％。鲁鲫鱼占6．2％－16．4％，鲢鳙鱼占8．1％－13．3％，鳊鲂占1．8％－11．3％，虾占5．9％－16．1％，其它鱼类占2．4％－9．3％。2000年大银鱼占总渔获的2．8％。1985－2000年水库鱼类资源相对稳定。亚洲公鱼、青虾和大银鱼三种小型经济鱼虾的种间关系表现为互利共生，竞争和残敌关系，可能向种间形成平衡调节方向发展。     

亚硫酸法降解沙棘籽原花色素的条件优化

以沙棘籽原花色素为原料、亚硫酸为降解剂,应用均匀设计法设计试验,考察降解时间、降解温度、料液比和亚硫酸用量对原花色素降解效果的影响.结果表明:亚硫酸法最佳降解条件为:温度80℃、时间60 min、料液比1:8(g:L)、亚硫酸体积分数为12％,在此条件下亚硫酸降解效果明显,降解前平均聚合度为13.42,降解后平均聚合度为7.53.     

不同刺槐种源根瘤菌16S rDNA的PCR-RFLP分析

为了研究不同刺槐种源根瘤茵的遗传多样性,采用4种限制性内切酶对分离自保定和高邑的38株不同刺槐种源根瘤茵进行16S rDNA PCR-RFLP多态性分析,共产生26种16SrDNA遗传图谱类型.UPGMA聚类分析结果显示,所有供试菌株分为4大类,第3类又分为3个亚类.16S rDNA全序列分析表明,代表菌株GY-2与S.morelense LMG20571序列相似性达到99.6％,在系统发育分类地位上属于Sinorhizobium.刺槐根瘤菌遗传多样性丰富,遗传差异受地理环境影响较大,与寄主种源相关性不明显.