饲养系统和日粮对羔羊屠宰性能和肌肉矿物质含量的影响

文章旨在探讨不同饲养系统和日粮对羔羊生长、屠宰性能及肌肉矿物质含量的影响。试验将平均体重为（13.97±0.55）kg的120只羔羊随机分为3组，每组4个重复，每个重复10只。T1组在室内饲喂基础浓缩料，每天补充100 g稻草，T2组在室内饲喂基础浓缩料，每天补充100 g稻草和锌硒复合矿物质（0.2 mg/d硒，50 mg/d锌），T3组在室外放牧，除了采食苜蓿草外，每天额外补充100 g稻草和100 g燕麦。试验时间为9周。结果：T1和T2组羔羊的末重、日增重、半胴体重、下肢深度、下肢重量、眼肌面积、颈、胸肌、肾重量均显著高于T3组（P＜0.05），但骨盆骨重量显著低于T3组（P＜0.05）。各处理组羔羊的可食用部分和骨盆肌肉重量无显著差异（P＞0.05）。T2组63 d羔羊血液硒含量较T1和T3组分别显著提高了19.83%和25.0%（P＜0.05），血液锌含量较T1和T3组分别显著提高了31.71%和45.91%（P＜0.05）。T3组羔羊肌肉钙含量较T1和T2组分别显著提高了8.79%和5.37%（P＜0.05）。T2羔羊肌肉硒和锌含量较T1和T3组分别显著提高了41.18%、65.52%和38.19%、46.15%（P＜0.05），T2和T3组羔羊肌肉钾含量较T1组分别显著提高了3.27%和4.28%（P＜0.05）。结论：在本试验条件下，放牧羔羊胴体的脂肪含量低于室内饲养的羔羊，室外放牧可以提高肌肉钙和钾含量，但肌肉硒含量降低。 [关键词]饲养系统|羔羊|屠宰性能|矿物质     

鸡皮刺螨实验室饲养与繁殖技术研究进展

鸡皮刺螨是一种吸血性外寄生虫,会引起鸡消瘦、贫血,并导致产蛋下降,造成巨大经济损失。为给科研提供可靠虫源,并对杀螨药物、疫苗以及其他防控手段进行效果评价,国内外学者进行了鸡皮刺螨实验室的人工饲养与繁殖技术研究。文章综述了国内外鸡皮刺螨实验室饲养与繁殖技术的研究进展,将其总结归纳为使用动物饲养繁殖技术与离体饲养繁殖技术两类,同时指出了各项技术在应用过程中存在的问题,为该技术的进一步完善与发展提供相关参考。     

城市池塘水质时间变化特性--以扬州大学江阳路南校区池塘为例

城市中的池塘是城市水体的重要组成部分,为揭示城市化背景下池塘水体水质的时间变化特性,选取扬州大学江阳路南校区池塘为研究区,对该池塘2018年7月至2019年6月的水质参数蓝绿藻浓度(Phyco)、水温(WT)、溶解氧(DO)、pH与电导率(EC)进行观测,采用变异系数法、单因子水质标识指数法以及多元线性回归法对各参数的变化特性进行评价。结果显示:池塘WT呈季节性变化;观测期间pH变化范围为7.74~9.98,水体呈碱性;DO变化的随机性较强,未表现出明显变化规律;各水质参数变异性及权重从大到小依次为WT>DO>EC>pH;以DO为指标的单因子水质标识指数结果表明:池塘DO达到Ⅲ类水要求的时段占总观测时段的84%;多元线性回归分析结果表明:DO与WT、pH呈正相关,与Phyco呈负相关,Phyco及pH的变化对DO浓度的影响相对于WT大。     

The effects of density and artificial substrate on intensive shrimp Litopenaeus vannamei nursery production

Recirculating aquaculture systems (RAS) can be installed indoors, allowing year-round production of tropical animals in nearly any climate. A nursery phase is commonly used in Litopenaeus vannamei production since it allows for enhanced biosecurity and better quantification of animals while reducing space requirements. However, it is unclear whether animal density and inclusion of artificial substrate may improve shrimp performance during the nursery phase. In this experiment, we compared shrimp production parameters in two stocking densities with or without the use of an artificial substrate by creating four treatments: low-density LD; 1500 PL/m⁻³, low-density with substrate LDS, high-density HD; 3000 PL/m⁻³), and high-density with substrate (HDS). The LDS and HDS treatments included 0.46-m² of high-density polyethylene 2.5-cm mesh as a substrate, which increased the tank surface area by 21 %. Each treatment was randomly assigned to four 160-l culture tanks, each with a biofilter. The shrimp had an initial weight of 4 mg and were grown for 50 days. The low-density treatments had significantly higher dissolved oxygen (DO) and pH than the high-density treatments (P ≤ 0.001). Specifically, LDS had the highest DO and pH followed by the LD, HD, and HDS treatments, respectively. High-density treatments had significantly higher NO₂-N levels than low-density treatments during week 2 of the experiment when an unusually high concentration of nitrite was observed. FCR was significantly lower in both low-density treatments than in high-density treatments. At harvest, the total biomass (kg m⁻³) was significantly higher in high-density treatments than in low-density treatments (P ≤ 0.001), and the HDS treatment had a significantly greater biomass output than HD. Producers should consider artificial substrate and higher densities during nursery production to maximize shrimp production; however, the effects on water quality should also be taken into account.     

下丘脑-垂体-肾上腺轴参与动物采食调控的研究进展

采食是动物维持生命活动的基本生理过程，是动物生长发育的基础。畜禽采食量的高低直接影响到营养物质的摄入量及生产性能的发挥。在畜牧业生产中，影响采食的因素很多，而应激是其中一个非常重要的影响因素。动物机体的应激反应主要由下丘脑-垂体-肾上腺（HPA）轴来调控。下丘脑、垂体和肾上腺皮质通过释放促肾上腺皮质激素释放激素（CRH）、促肾上腺皮质激素（ACTH）和糖皮质激素（GC）这3种应激激素来协同调控动物的应激反应。应激激素对采食行为的调节是一个非常复杂的过程，主要通过稳态和非稳态途径来调节采食，可以双向调控食物的摄入量。稳态途径指的是通过调控机体能量稳态而调控采食。CRH和ACTH通过抑制下丘脑促食欲肽的表达而抑制采食；而GC在中枢和外周发挥着完全相反的作用。非稳态途径指的是通过影响中脑奖赏系统调控采食的愉悦感，是近年来食欲调控研究的热点，越来越多的研究证明了应激激素与奖赏系统的联系。作者针对应激激素调控采食的最新研究报道进行综述，以期为生产实践中新型的采食调控技术研发提供一定的参考。     

船舶噪声声压级对大黄鱼幼鱼游泳、摄食行为及免疫生理指标的影响

通过录制大黄鱼(Larimichthys crocea)产卵场附近船舶航行时的噪声,并以此为刺激源,以大黄鱼幼鱼为实验对象,研究了船舶噪声声压级对大黄鱼幼鱼游泳、摄食行为及免疫生理指标的影响。研究发现,当噪声声压级<60 dB时,幼鱼趋避游泳行为不强烈;但随着声压级增大,开始呈现出不同强度的趋避行为,依次表现出:游泳速度加快、鱼与鱼之间及鱼与桶壁之间发生碰撞、瞬间反应无序、跳跃等行为;当声压级>200 dB时,刺激2 min后就出现了死亡个体。在120 dB和150 dB短期单次和多次刺激下,幼鱼血浆中的皮质醇、血糖、血红蛋白和乳酸这4个与应激相关的生理指标均显著上升,其中皮质醇、血糖和乳酸上升幅度尤为明显。另外,皮质醇单次刺激后即达到峰值,而多次刺激后反而较单次刺激有所下降;血糖、血红蛋白和乳酸则具有累加效益,多次刺激要高于单次刺激。在120 dB长期(30 d)刺激下,幼鱼生长明显减缓,血浆中部分免疫指标(免疫球蛋白M,干扰素-α,白介素-1β和肿瘤坏死因子-α)明显降低,肠道菌群也发生显著变化,突出表现为部分益生菌如芽孢杆菌、乳杆菌等相对丰度明显降低。摄食行为影响方面,研究发现幼鱼能准确识别噪声源的位置,并具有一定的记忆性。研究结果揭示了船舶噪声对大黄鱼幼鱼的危害,可为今后制定大黄鱼产卵场的保护措施提供数据支撑。     

胰α-淀粉酶基因5''端调控序列与鱼类食性的关系

为了研究不同鱼类胰α-淀粉酶基因5'端调控序列转录因子差异与鱼类食性分化之间的关系。通过PCR克隆测序和查询NCBI数据库,获得32种鱼类胰α淀粉酶基因5'端824 bp序列,并对鱼类胰α淀粉酶基因5'端序列进行转录因子和系统发育分析。按不同的营养类型将鱼类分为杂食性、植食性和肉食性,通过百分比相似性分析不同食性鱼类的胰α淀粉酶基因转录因子的组成差异以及转录因子与鱼类食性的关系。结果显示:不同食性鱼类的胰α-淀粉酶基因5'端序列存在转录因子种类差异,植食性-肉食性鱼类差异主要体现在E47、C/EBPalpha、NF-Y和Pax-2,植食性-杂食性差异主要体现在deltaEF1、MyoD、NF-Y、AREB6和Pax-2,杂食性-肉食性差异主要体现在GATA-1、SRY、MyoD、HFH-8、AREB6、Pax-2、STAT5A和AP-1。系统发育结果与传统形态分类学大体相符,相同食性的鱼类并没有聚为一类。鱼类胰α-淀粉酶基因5'端调控序列中与食性分化相关的转录因子有E47、C/EBPalpha、NF-Y、Pax-2、deltaEF1、MyoD、AREB6、GATA-1、SRY、HFH-8、STAT5A和AP-1;胰α-淀粉酶基因5'端序列的转录因子与鱼类食性分化具有一定的关系。     

采食后奶牛瘤胃短链脂肪酸及其吸收相关蛋白表达的研究

本试验旨在研究奶牛采食前后瘤胃中短链脂肪酸(SCFA)浓度的变化及其吸收相关蛋白表达量的差异。试验选用3头体重(720±30)kg且装有瘘管的健康荷斯坦牛(动物伦理审查编号为SXAU-EAW-2019-C002013),采食精粗比为40:60的日粮(10kg),试验预试期10d,于第11天饲喂前开始取样,采用气相色谱法检测奶牛采食前(0 h)和采食后(1、2、3、4、5、6、7、8 h)瘤胃液中SCFA浓度;并采用荧光定量PCR方法检测瘤胃上皮组织中与SCFA吸收相关的蛋白表达量。结果表明:在采食后1 h奶牛瘤胃中SCFA浓度最高(P<0.05);在采食后一段时间内(2~5h)与SCFA吸收相关蛋白表达量上调(P<0.05),AE2、MCT1基因表达量均在5 h最高,PAT1、NHE3基因表达量均在4 h最高,MCT4基因表达量在4、5、6h均较高,NHE1基因表达量在2h达到最高;AE2、MCT1、MCT4、NHE1基因表达量与SCFA浓度负相关或正相关(P<0.05),AE2、MCT1、MCT4基因表达量与瘤胃内pH正相关(P<0.05)。以上结果初步揭示,在采食后一定时间内,瘤胃中与SCFA吸收相关蛋白表达受SCFA浓度和pH的调节。     

设施畜牧业关键技术研究态势分析

[目的/意义]目前中国畜牧业正处于加快转型的重要时期,了解相关技术的发展态势对于畜牧业的发展具有一定的借鉴意义。[方法/过程]本文以设施畜牧业领域技术研发的3个主要方向：笼舍技术、饲喂饮水技术和环境控制技术的相关专利为研究对象,利用专利计量的方法对其发展趋势、技术分支、申请人、各阶段重点专利等进行了分析。[结果/结论]笼舍、饲喂饮水和环境控制技术发展同步经历了萌芽期、波动发展期、快速发展期3个阶段,当前申请量呈现直线上升的态势;技术研发主体以企业为主,各研发单位之间技术布局差异性明显;近些年重点专利中的国内专利明显增多;笼舍技术方面装置研发均侧重于粪尿清除、垫板等技术;饲喂饮水技术方面饲喂技术的研究多于饮水技术,且均侧重于研发自动化设备;环境控制技术侧重于废弃物处理技术、空气调节技术和房舍清洁刷洗技术。     

Comparing biofloc,clear-water,and hybrid nursery systems (Part I): Shrimp (Litopenaeus vannamei) production,water quality,and stable isotope dynamics

Indoor, intensive, nursery-based recirculating aquaculture systems (RAS) can provide high-quality juvenile shrimp for indoor or pond-based production systems in a biosecure manner. However, it is unclear what type of RAS is most appropriate for indoor shrimp nurseries. This study compared three types of RAS nurseries: biofloc (BF), clear-water (CW), and hybrid (HY). Each treatment included four, randomly assigned 160 L (0.35-m²) tanks that were stocked with 3000 post-larvae shrimp m⁻³. The post-larvae (PL10) shrimp had an initial average weight of 7 ± 0.0 mg and were grown for 48 days. The BF tanks included external settling chambers as the only filtration mechanism. The CW tanks had settling chambers, foam fractionators, and external biofilters to fully clarify the water and process nitrogenous waste. Hybrid tanks included settling chambers, and external biofilters to maintain some suspended solids along with external biofiltration. Overall, the CW treatment had significantly higher dissolved oxygen (DO) and pH levels than the BF and HY systems. The HY treatment had significantly higher DO than the BF treatment. Nitrite concentration was significantly higher in the HY treatment than the CW treatment. Turbidity in the BF treatment was significantly higher than the other treatments. On the final sample date, the BF treatment had significantly higher nitrite and nitrate concentrations than the other treatments. Differences between treatments in terms of shrimp survival, mean harvest weight, specific growth rate, and feed conversion ratio were not significant. The final weight of the shrimp at 48 days for the BF, CW, and HY were 670 mg, 640 mg, and 590 mg respectively. A stable isotope mixing model indicated that, in the BF treatment, 13% of the C and 34% of the N in harvested shrimp tissue may have originated from biofloc material, signifying some nutrient recycling. The nitrification process was more effective with the inclusion of an external biofilter. All three system types appear suitable for RAS shrimp nursery production although consideration should be given to water quality consistency and filtration costs.