强制换羽对蛋鸡生产性能和蛋品质的影响

旨在研究强制换羽对蛋鸡生产性能和蛋品质的影响。选取80周龄海兰褐蛋鸡4 500只,分为A、B、C组,每组1 500只,于试验组Ⅰ区饲养;选取60周龄海兰褐蛋鸡3 000只,分为D、E组,每组1 500只,于试验组Ⅱ区饲养;另选取60周龄海兰褐蛋鸡1 500只（F组）,于对照组Ⅲ区饲养。试验组Ⅰ区和试验组Ⅱ区位于同一栋鸡舍,对照组Ⅲ区位于另外一栋鸡舍。采取饲料、饮水、光照控制的方式对A~E组鸡群进行强制换羽处理;F组不进行强制换羽处理。试验包括7 d的预试期和56 d的正试期。在正试期内,测定各组鸡群的产蛋率、蛋品质指标、死亡率。结果表明：与换羽前相比,强制换羽后A、B、C组的平均产蛋率的提高幅度为27.1%,强制换羽后D、E组的平均产蛋率的提高幅度为16.1%,换羽后F组的平均产蛋率的降低幅度为5.5%;5个接受强制换羽处理的试验组（A~E组）与对照组（F组）相比,蛋重增加2.5%,蛋壳强度提高11.8%,蛋白高度提高8.8%,蛋形指数提高3.3%,蛋壳尖端的厚度提高14.8%;5个接受强制换羽处理的试验组（A~E组）的平均死亡率为2.5%,对照组（F组）的死亡率为1.5%。综上所述,强制换羽技术的应用可以明显提高海兰褐蛋鸡的产蛋率,并提升蛋品质。     

中华绒螯蟹三种亲本规格子代的生长、肠道微生物菌群和代谢组学分析

中华绒螯蟹(Eriocheir sinensis)繁育亲蟹规格及其子代的生产性能是其产业上的热点问题。本研究应用个体生长测定法和代谢组学技术，研究了当前生产上3种主要育苗亲蟹规格（母本200~250g，父本300~350g；母本250~300g，父本350~400g；母本300g以上，父本400g以上）繁殖子代（规格A、规格B和规格C）的蜕壳与生长特性、肠道微生物菌群和肝胰腺代谢物的组成差异。结果发现：在2次个体蜕壳与生长测定中，规格C的生长性能优于其他两种规格，但3种规格子代相互间的蜕壳增重率、蜕壳间隔、肥满度、肝胰腺指数和肌肉指数均不存在显著差异。肠道菌群结果表明：α多样性指数均显示规格A低于其他两种规格，但3规格相互间无显著差异，而主坐标分析（PCoA）显示3种规格肠道菌群在属水平上存在显著差异。肝胰腺的代谢组学分析显示，规格A与B间共有100种差异代谢物，规格B与C间共有77种差异代谢物，规格A与C间共有79种差异代谢物。对差异肠道菌群和差异代谢物进行Pearson相关性分析发现：规格A的代谢物生物喋呤与副梭菌属呈显著正相关；规格B的代谢物N-乙酰-D-甘露糖胺分别与硝基螺菌门、硝化螺菌属呈显著负相关；规格C的代谢物四氢二吡啶甲酸盐与乳酸菌属呈显著负相关。本研究结果初步表明：不同亲蟹规格子代在生长性能、肠道微生物菌群和肝胰腺代谢物组成方面表现出一定差异。     

Effects of Artemia enriched with eicosapentaenoic and docosahexaenoic acid on survival and occurrence of molting failure in megalop larvae of the mud crab Scylla serrata

ABSTRACT:   The present study was conducted to investigate the effect of eicosapentaenoic acid (20:5n-3, EPA) and docosahexaenoic acid (22:6n-3, DHA) on the survival and the occurrence of molting failure to megalops of mud crab Scylla serrata larvae fed enriched Artemia . Survival rate, intermolt period, carapace width at the first crab stage, ratio of chela to carapace length at the fifth zoeal stage and the occurrence of molting failure to megalops were observed. Mud crab larvae were reared in 1-L plastic beakers and fed with Artemia enriched at five different levels of EPA (0.31% to 1.36% EPA; referred to as E25, E50, E75 and E100) or four different levels of DHA (0.75–0.95% EPA and 0.49–1.38% DHA; referred to as D25, D50, D75 and D100). As a negative control, larvae were fed Artemia enriched with oleic acid (OA). Mud crab larvae fed Artemia containing low (0.41–0.45% EPA and trace DHA) or high (1.36% and 0.95% EPA and 0.16% and 1.38% DHA) amounts of EPA and DHA showed a significantly lower survival rate and prolonged intermolt period ( P  < 0.05). Moreover, a high frequency of molting failure to the megalops stage (34 and 33%) occurs coincident with a high chela to carapace length ratio (43 and 44%) in mud crab larvae fed high amounts of EPA and DHA (E100 and D100), suggesting that both of these treatments contain EPA and DHA in excess. These results indicate that during Artemia feeding, EPA and DHA content should be adjusted to 0.71–0.87% and 0.49–0.72% for maintaining a high survival, accelerating the intermolt period, and producing larger carapace width in the first crab stage.     

昆虫蜕皮的激素调控网络

昆虫蜕皮是由数种激素分级调控的一个重要生长发育过程。在蜕皮之前,脑神经分泌细胞合成和分泌促前胸腺素(prothoracicotropic hormone,PTTH)并促进前胸腺中蜕皮激素(ecdysone,Ecd)的产生。随后,Ecd促进气门腺Inka细胞合成蜕壳启动激素(ecdysis-triggering hormone,ETH),同时抑制ETH的分泌,对ETH具有双重调控作用。血淋巴中Ecd滴度下降后,羽化激素(eclosion hormone,EH)促进ETH的分泌。最终,ETH启动昆虫的蜕皮。     

蚕用蜕皮激素水剂含量检测探讨

我省蚕用蜕皮激素水剂含量检测是根据《四川省蚕药标准》(1992年版)制订的紫外分光光度检测法,该方法用于检测蚕用蜕皮激素水剂含量时受水剂中的糖苷,蛋白质、色素等大分子物质影响,测出值与实际值有较大误差,而用高效液相色谱检测法能较好地避免大分子物质的干扰,减少误差,其效果明显优于紫外检测法.     

小贯小绿叶蝉蜕皮、羽化及孵化节律

通过室内单头饲养小贯小绿叶蝉,观察了其蜕皮、羽化及孵化的时间规律.结果表明,1龄若虫蜕皮时间为(4.83±0.13)min,2龄若虫为(5.14±0.13)min,3龄若虫为(5.07±0.11)min,4龄若虫为(5.64±0.17)min;1、2龄若虫蜕皮数量在24 h内分布比较均匀,3龄若虫蜕皮时间集中在2:00-4:00,4龄若虫多在4:00-7:00和16:00-19:00蜕皮.雌虫羽化时蜕皮过程持续(8.15±0.18)min,雄虫持续(8.02±0.21)min;雌虫整个羽化过程需要(16.82±0.27)min,雄虫需要(16.15±0.29)min,雌雄虫间无显著差异;雌雄虫羽化高峰分别在5:00-12:00和4:00-11:00.卵孵化持续时间为(7.42±0.52)min,孵化的高峰出现在5:00-8:00.     

中华绒螯蟹Akt基因的cDNA克隆、序列分析及表达特征

为研究Akt基因在中华绒螯蟹蜕壳前后肌肉生长过程中的功能,应用RACE技术克隆得到编码中华绒螯蟹Akt(命名为Es Akt)的全长为2 200 bp的c DNA序列,包括159 bp的5′非翻译区(5′-UTR)、496 bp的3′非翻译区(3′-UTR)和长度为1545 bp编码514个氨基酸的编码序列。蛋白质结构域分析显示Es Akt含有丝氨酸/苏氨酸蛋白激酶家族的3个特征性保守结构域。多序列比对和系统发育分析显示,Es Akt与中国明对虾、凡纳滨对虾的Akt序列一致性都为0.889,在系统发育树中节肢动物Akt形成一个分支。应用荧光定量RTPCR技术分析Es Akt在性成熟中华绒螯蟹各组织及幼体不同蜕壳时期不同部位肌肉组织中转录水平上表达量的变化。结果显示,Es Akt在性成熟个体的肝胰腺、眼柄、表皮、卵巢、精巢、心脏、螯足、鳃、三角膜等组织中均有表达,其中卵巢、眼柄和精巢中表达量较高,肝胰腺中表达量最低。在幼体不同蜕壳时期不同部位的肌肉中,Es Akt表达量变化不同,步行足肌肉组织中Es Akt m RNA无显著的统计学差异。腹部肌肉组织中Es Akt m RNA水平在蜕壳前晚期D3~D4期表达量显著高于蜕壳后A~B期和蜕皮间期C期。螯足肌肉在蜕壳前晚期D3~D4期急剧下调,蜕壳后A~B期开始表达量显著升高,直至蜕皮间期C期。研究表明,Es Akt在中华绒螯蟹蜕壳过程中不同部位肌肉组织中的表达量变化与蜕壳周期密切相关,说明Es Akt参与中华绒螯蟹蜕壳诱导的肌肉萎缩、生长及重建过程。     

Effects of freeze‐dried powder of the Antarctic krill Euphausia superba on the growth performance,molting and fatty acid composition of the Pacific white shrimp Litopenaeus vannamei

This study was designed to evaluate the effect of dietary replacement fish meal supplemented with freeze‐dried powder of the Antarctic krill Euphausia superba (FDPE) on the growth performance, molting, and fatty acid composition of the Pacific white shrimp Litopenaeus vannamei (initial weight 1.27 ± 0.09 g). Four diets containing 0% (S0 group), 10% (S10 group), 20% (S20 group), and 30% (S20 group) FDPE were used in the present study. At the end of growth trial, the final body weight, weight gain rate, and specific growth rate in the S10, S20, and S30 groups were higher than those in the S0 group. The shrimp in the S10 and S20 groups exhibited better molting synchronism than those in the S0 group. The astaxanthin content in the hepatopancreas from the shrimp in the groups supplemented with FDPE was significantly higher than that in the S0 group (p < 0.05) and increased as the FDPE content in the feed increased. The shrimp in the S10, S20, and S30 groups had a higher monounsaturated fatty acid (MUFA) content in the hepatopancreas than those in the S0 group. The sum of EPA and DHA in the muscles from the shrimp in the S0 group was lower than that in the other groups. These results indicate that the dietary inclusion of 10%–20% FDPE can be used as practical diets in L. vannamei farmed under a clear water system.     

蜕皮激素对黑化黏虫体液免疫的影响

为揭示蜕皮激素(MH)对黑化黏虫免疫能力的影响, 本试验对被球孢白僵菌侵染后的黏虫体内MH含量的动态变化进行了分析比较, 并对被侵染的黑化黏虫注射20-羟基蜕皮酮(20E), 分析比较其注射20E后的死亡率以及酚氧化酶(PO)和溶菌酶活性的变化?结果表明:被白僵菌侵染后, 黑化黏虫6龄幼虫的MH含量在侵染后8 h( P <0.05)?72 h( P <0.05)和96 h( P <0.05)均显著高于对照(注射吐温-80)?注射球孢白僵菌后立即注射5 μg/μL的20E稀释液, 黑化黏虫的死亡率显著低于对照组(注射球孢白僵菌后注射无水乙醇)( P <0.05), 其原因是注射5 μg/μL 20E稀释液后, 被球孢白僵菌侵染后8 h和24 h的黑化黏虫体内PO和溶菌酶活性均显著高于对照组(注射球孢白僵菌后注射无水乙醇)( P <0.05)?试验结果表明MH在黏虫体液免疫反应中起到重要的调节作用?