温度和食物对褶皱臂尾轮虫种群增长及繁殖的影响     

董婧  于业辉  赵莹莹  卫侃韵  高海钰  李林 《现代畜牧兽医》2014,(4):35-39

本试验设3个温度（20、25和30℃）和3个食物浓度（1×106、10×106和20×106 cells/mL）,研究不同温度和不同食物浓度对褶皱臂尾轮虫种群增长及繁殖的影响。试验期为10 d。结果表明,最大种群密度均随温度和食物浓度的升高而先增加后减少。温度为25℃食物浓度为10×106 cells/mL时,最大种群密度为74.39±1.81 ind/mL,与其他组比差异显著（P〈0.05）。随温度升高,轮虫的最大种群密度高峰值出现的时间也呈现逐渐前移的趋势,最大种群增长率则随温度和食物浓度的增加而升高。温度30℃食物20×106 cells/mL时,最大种群增长率为0.70±0.013,与其他组比差异显著（P〈0.05）。食物浓度对轮虫的怀卵率有显著影响,在同一温度下最大怀卵率随食物浓度的升高而增大,食物为20×106 cells/mL的最大怀卵率为56.43±1.07%,与其他浓度组比差异显著（P〈0.05）。在本试验条件下,温度和食物对褶皱臂尾轮虫的种群增长及繁殖均有显著影响。温度25℃食物浓度10×106 cells/mL为培养条件的最优组合。  相似文献   

山羊骨髓间充质干细胞的分离培养     

王利  陈琦  贾宇臣  郑源强  李少伟 《畜牧与饲料科学》2014,(12):4-6

旨在对山羊的骨髓间充质干细胞(BMSCs)进行分离培养。将分离得到的BMSCs进行传代培养,采用RT-PCR法检测其干细胞转录因子oct4和sox2基因,以验证其干细胞特性;在此基础上绘制BMSCs的生长曲线,对其生物学特性进行直观了解。结果表明,分离到的山羊BMSCs原代细胞呈现出成纤维样,并能够表达oct4和sox2基因,证明了其干细胞特性;其生长曲线呈"S"型,在1~2 d时为潜伏期,第3天时进入指数生长期,第7天时进入平台期。结果提示,分离得到的细胞具有BMSCs的特性,能够用于后续的相关试验研究。  相似文献   

日粮赖氨酸水平对12～18周龄雌性临武鸭生长性能及肠道结构的影响          下载免费PDF全文

蒋桂韬  林谦  张旭  王向荣  戴求仲 《家畜生态学报》2014,35(11):33-36

为研究12~18w临武鸭的赖氨酸需要量,试验随机选取健康、体重接近的84日龄雌性临武鸭210羽,分为5个处理(赖氨酸水平分别为0.55%、0.65%、0.75%、0.85%、0.95%),每处理设6个重复,每重复7只鸭,试验全期为42d。结果显示:(1)12~18周龄雌性临武鸭增重较慢,且各组试鸭间平均日采食量和日增重差异均不显著(P0.05),但0.75%赖氨酸组有增加平均增重的趋势;(2)试验各组间试鸭的十二指肠绒毛高度、隐窝深度、绒毛高度/隐窝深度差异均不显著(P0.05),但有增加绒毛高度的趋势。试验结果表明,以生长性能和肠道结构为评价指标,本试验条件下12~18w龄雌性临武鸭日粮赖氨酸水平以0.75%为适宜。  相似文献   

饲粮半胱氨酸水平对獭兔生产性能和SLC1A4基因表达的影响          下载免费PDF全文

曾洁  张恩平  陈玉林  周英昊 《家畜生态学报》2014,(10)

试验旨在研究饲粮中半胱氨酸含量对獭兔生长性能、毛皮品质和SLC1A4基因表达的影响。选取90日龄健康獭兔144只,随机分为4组(每组36个重复,每个重复1只)。对照组饲喂基础饲粮(半胱氨酸含量为0.25%),试验组饲喂半胱氨酸含量分别为0.60%、0.70%和0.80%的试验饲粮(在基础饲粮中分别添加0.35%、0.45%和0.55%半胱氨酸)。预饲期7d,正饲期40d。试验期间每隔10d,每组随机屠宰4只獭兔,取样测定皮毛品质和SLC1A4基因表达。结果表明:(1)饲粮半胱氨酸水平为0.70%的试验组末重和平均日增重显著提高(P0.05);料重比显著降低(P0.05);四个组间平均日采食量差异不显著(P0.05)。(2)饲粮半胱氨酸水平为0.60%和0.70%的试验组饲喂到130日龄时皮张面积显著增大(P0.05);三个试验组獭兔在100日龄时被毛密度均显著大于对照组(P0.05);半胱氨酸水平为0.70%的试验组被毛密度在130日龄时显著大于其他三个组(P0.05);半胱氨酸对獭兔皮张厚度无显著性影响(P0.05)。(3)饲粮半胱氨酸含量对獭兔皮肤、肝脏和十二指肠组织中SLC1A4基因的表达量影响极显著(P0.01)。SLC1A4基因的表达量均呈现先增高后降低的趋势,饲粮中半胱氨酸水平为0.70%的试验组达到最高值。这一趋势在皮肤组织中、肝脏和十二指肠组织中分别于110日龄和100日龄时表现得较为显著。由此可见,獭兔饲粮中半胱氨酸的最优水平为0.70%,且在110日龄前使用效果最佳。  相似文献   

东海区刺鲳生长、死亡及资源利用状况评价   总被引：1，自引：1，他引：1  

胡芬 《水产学报》2006,30(5):622-668

利用2001-2005年东海区26°30′～32°30′N，禁渔区线外200水深以浅的东海区大陆架海域底层拖网调查资料和生物学测定资料，利用ELEFAN I软件估算生长参数，拟合von-Bertalanffy生长方程,估算死亡系数，利用Beverton和Holt模型评价资源利用状况。研究结果表明：东海刺鲳的Von Bertalanffy生长方程的生长参数为:L_∞ =267.8 mm；K=0.45/a；t₀=-0.63 a。从生长速度看其生长过程是变化的，小时生长较快，当叉长达到178.5 mm时生长速度开始下降，此时年龄为1.81 a。利用Pauly公式和詹秉义等推导的M和最大年龄t_λ的线性回归方程求得自然死亡系数M=0.81，用FiSAT II软件中的长度变换渔获曲线法、BH模式和用CPUE估算总死亡系数，得到Z=3.87，捕捞死亡系数F=3.06。根据Beverton和Holt的单位补充量等渔获量曲线，现行渔业点即F=3.06，t_c=1.10 a位于最适产量区内，表明目前对刺鲳的资源利用较为合理，接近最大产量。保持目前的捕捞强度F=3.06和捕捞规格L_c=145 mm不变，不仅能够保持目前渔获量稳定，而且能够保护刺鲳的资源。刺鲳渔获量稳定且缓慢增长的重要原因在于开捕年龄较为合理，也就是网目尺寸较为合适，这对东海区主要经济鱼类资源的管理和保护具有很大的借鉴作用。  相似文献   

投喂频率对凡纳滨对虾生长和水质的影响     

叶乐  林黑着  李卓佳  吴开畅  文国樑  马之明  朱昌福 《南方水产》2005,1(4):55-59

研究了不同投喂频率(1,2,3,4和5次·d-1)对凡纳滨对虾生长、存活率和水质的影响。试验在室内2m3的圆形水泥池(d=1.6m)中进行,采用全封闭养殖模式,凡纳滨对虾(初始重量为0.24g)养殖密度为50尾·m-3,投喂人工配合饲料(粗蛋白含量为42.98%)。通过7周的试验,结果表明,投喂频率为1～4次·d-1时,随着投喂频率的增加,对虾增重率显著增加;投喂频率由4次·d-1增加到5次·d-1时,对虾增重率略有增加,但差异不显著。凡纳滨对虾的成活率在1次·d-1时最低,2次·d-1时最高,2～5次·d-1时随着投喂频率的增加而降低(投喂频率为1和2次·d-1之间、3和4次·d-1之间差异显著)。投喂频率为3次·d-1时饲料系数最低,蛋白质效率最高。随着投喂频率1～3次·d-1增加,饲料系数逐渐显著降低,蛋白质效率显著递增;而投喂频率从3～5次·d-1增加时,饲料系数增大,蛋白质效率逐渐下降(3和4次·d-1差异显著;4和5次·d-1之间差异不显著)。投喂频率对水环境中的pH值、H2S含量、COD、盐度等水质指标没有显著影响;在养殖后期水环境中投喂频率3～5次·d-1的NH 4和NO-2浓度较投喂频率1～2次·d-1时高。  相似文献   

Growth testing of two breeds of common carp, Cyprinus carpio L. (Hungarian mirror and Třeboň scaly carp), in ponds with low and high stocking density     

P Hartvich  M Flaj&#;hans  V Nýdl  T Vondra  & T Pavlí&#;ek 《Aquaculture Research》2003,34(12):1015-1021

The growth of two breeds of common carp, Cyprinus carpio L., was tested in ponds under the climatic conditions of South Bohemia. T?eboň scaly carp (TR) and Hungarian mirror carp (M2) were kept in both low and high stocking densities during the second growing season and then stocked together for communal testing during the third growing season. Before the communal testing, the mean initial weights of fish from low‐ and high‐density stocks differed significantly (374.1 vs. 227.7 g for the TR breed and 766.7 vs. 317.3 g for the M2 breed respectively, P<0.01). After communal testing, mean weights of fish from low‐ and high‐density stocks gained 761.8 vs. 543.8 g for the TR breed and 1339.7 vs. 706.7 g for the M2 breed respectively. These observed weights were also significantly different (P<0.01). However, the test of corrected weight gain, i.e. gain not related to the initial weight of fish, revealed insignificant differences (P>0.01) between the weight gains after correction, i.e. the effect of different initial weights was successfully eliminated. These results seem to confirm the applicability of this method for the assessment of growth of purebred common carp under the climatic conditions of Central European fish farms.  相似文献   

Weaning of juvenile pikeperch, Stizostedion lucioperca L., and perch, Perca fluviatilis L., to formulated feed     

L Ljunggren  F Staffan  S Falk  B Lindén  & J Mendes 《Aquaculture Research》2003,34(4):281-287

Weaning success of pond‐cultured pikeperch and wild‐caught perch (mean length 51 and 48 mm respectively) was evaluated using different weaning techniques and different formulated feeds. Juveniles that were fed formulated feed grew as well as or better than juveniles that were weaned successively using zooplankton or yolk. Four different formulated feeds (agglomerated marine larvae feed, marine larvae feed, trout feed and a semi‐moist feed) were evaluated regarding specific growth rate (SGR), condition factor and a subjective stomach fullness estimate. The agglomerated marine larvae feed gave significantly better weaning performance than the other feeds regarding all parameters (SGR = 7.3% day^?1 and 3.4% day^?1 for pikeperch and perch respectively).  相似文献   

Using patch studies to link mesoscale patterns of feeding and growth in larval fish to environmental variability   总被引：1，自引：0，他引：1  

John F. Dower  Pierre Pepin  & William C. Leggett 《Fisheries Oceanography》2002,11(4):219-232

We present results from a series of three patch studies designed to examine links between environmental variability and mesoscale patterns of feeding and growth of larval radiated shanny ( Ulvaria subbifurcata ). We examine the effects of variability in temperature, turbulence and prey concentration on both the mean (i.e. population level) and the variance (i.e. individual level) of larval feeding and growth rates among the three bays. Although both gut fullness and growth rates differ significantly between bays, our results show only weak environmental influences. When larvae are pooled across bays (i.e. treated as independent observations), environmental factors generally explain <4% of the variability in gut fullness. When treated as daily mean residuals, however, temperature accounts for 41% of the variability in mean gut fullness, while both temperature and prey concentration also explain significant portions of the variance in gut fullness (38 and 43%, respectively). Between-bay differences in larval growth rates are consistent with patterns of temperature variation but not with patterns of prey availability. Studies relying on tracking a single patch of larvae typically suffer from having too few observations to detect significant relationships between feeding or growth and environmental variables. By following three patches we collected a larger number of observations. However, as we encountered only a limited range of environmental conditions it remains difficult to adequately assess the role of environmental factors. In part, this problem stems from the inability of fisheries oceanographers to track the recent environmental history of individual larvae on the same fine scales currently employed to collect biological data (e.g. guts and otoliths) on individuals.  相似文献   

Modelling the temperature mediation of growth in larval fish   总被引：1，自引：0，他引：1  

Joachim Bartsch 《Fisheries Oceanography》2002,11(5):310-314

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