Experimental induction of infectious pancreatic necrosis in Atlantic salmon, Salmo salar L., post-smolts     

K Stangeland  S Høie  T Taksdal 《Journal of fish diseases》1996,19(4):323-327

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Response of a Juvenile Cyprinid,Lake Minnow <Emphasis Type="Italic">Eupallasella perenurus</Emphasis> (Pallas), to Different Diets     

Rafa??KamińskiEmail author  Micha??Korwin-Kossakowski  Jan?Kusznierz  Leszek?Myszkowski  L. Andrzej?Stanny  Jacek?Wolnicki 《Aquaculture International》2005,13(5):479-486

Three commercial starters (Carp Starter, Uni Starter and Perla Plus) and one non-commercial, with frozen Chironomidae larvae as a reference diet, were evaluated for the intensive rearing of juvenile lake minnow Eupallasella perenurus, a cyprinid fish that is critically endangered in Poland. The growth, condition, survival, body deformities, and chemical body composition were studied. The 90-day laboratory experiment was performed at 22 °C with fish that were initially 24.6 mm (mean total lenth (TL)) and 0.11 g (mean body weight (BW)). Satisfactory fish growth was attained with all of the diets; however, the largest (p ≤ 0.05) final size (48.5 mm TL, 1.55 g BW) and the lowest condition coefficient (K = 1.34) were noted in fish fed the non-commercial starter. The final survival rates were very high (97.5–100%). Skeletal deformities (in 74 to 92% fish) were recorded exclusively in fish fed commercial starters. All commercial starters resulted in considerably higher lipid content and lower ash content than did the non-commercial starter and the reference diet. This suggests that both these factors might be responsible for body deformities. The present results proved that only the non-commercial starter is suitable for juvenile E. perenurus rearing under controlled condition, and that none of the commercial starters can be recommended.  相似文献   

Movement of the fluvial form of masu salmon, <Emphasis Type="Italic">Oncorhynchus masou masou</Emphasis>, in a mountain stream in Kyushu,Japan     

Kazuhiro?SakataEmail author  Takuya?Kondou  Naohiko?Takeshita  Akinobu?Nakazono  Seir??Kimura 《Fisheries Science》2005,71(2):333-341

Using mark-recapture methods, the movements of the fluvial form of masu salmon (Oncorhynchus masou masou) in a mountain stream on the island of Kyushu, Japan, were studied. Most (78%) of the masu salmon were recaptured in the pool in which they had been originally caught and tagged. Of those that moved between pools, the proportion of individuals that moved during the breeding period was not significantly higher than the proportion that moved during the non-breeding period. However, during the breeding period, a higher proportion of larger salmon moved than did smaller fish. The proportion of mobile large males during breeding period was higher than that for small males. Also, it was found that a few individuals showed long-range movement in the autumn. As a long-term movement, 78 individual fish (65%) that were recaptured more than three times showed high sedentary tendencies. Sixteen individual mobile fish (13%) moved and returned to the original pool. Fluvial form of masu salmon in Kyushu show a high sedentary nature; however, large mature males seem to actively move in search of female during breeding period.  相似文献   

Growth of the fourspine sculpin <Emphasis Type="Italic">Cottus kazika</Emphasis> in the Gonokawa River,Japan, and effects of water temperature on growth     

Naohiko?TakeshitaEmail author  Itaru?Ikeda  Norio?Onikura  Masato?Nishikawa  Singo?Nagata  Seiichi?Matsui  Seir??Kimura 《Fisheries Science》2005,71(4):784-790

ABSTRACT:   The fourspine sculpin Cottus kazika is indigenous to Japan and found in Honshu except for the waters facing the Seto Inland Sea, and was also found in southern Shikoku and eastern Kyushu. This species has a catadromous lifestyle and migrates as juveniles from the sea to the middle reaches of rivers to grow. The growth pattern of this fish was investigated by a mark-and-recapture method from July 1994 to December 1996, in the Nigorikawa River, a tributary of the Gonokawa River system, Shimane Prefecture. 0-year-old fish of 50–70 mm total length ( TL ) occurred in the study area from June to July, grew to 90–140 mm  TL by the following April, and attained 160–210 mm  TL by December. This fish grew rapidly in September–November and April–July, almost ceasing to grow in July–September. It seems that this stagnant growth phase in summer is a characteristic of the seasonal growth pattern of C. kazika . A rearing experiment indicated that the growth rate of C. kazika was higher at 16–22°C than at 12–14 and 24–26°C. This result supports the field evidence of a stagnant growth phase in summer in the Nigorikawa River.  相似文献   

论休闲时代民族传统体育的发展     

冉启琴  夏思永 《西南大学学报(自然科学版)》2014,36(5)

21世纪,人类面临着全球化休闲时代的到来,体育活动成为休闲娱乐的主要方式,体育进入休闲,是社会和谐发展和小康生活的标志。中华民族传统体育是中华各民族在生产、生活和娱乐中创造并沿袭下来的体育活动的总称,它无论从起源和特点上,还是从功能上看都与休闲娱乐不谋而合。因此,我们应充分把握休闲时代的契机,大力发展民族传统体育。  相似文献   

材料连接技术课程教学改革与实践探索     

徐尊平  强华  陈志谦 《西南大学学报(自然科学版)》2014,36(5)

分析了目前材料连接技术课程教学中存在的不足,从教学内容、教学方式与手段、实践教学与教学质量评价体系等方面入手,探讨了材料连接技术课程教学改革的基本思路。实践表明,课程教学改革的实施有利于提高学生的综合能力。  相似文献   

基于储油罐变位识别的数学模型研究     

张星星  胡沛  王振凯 《西南大学学报(自然科学版)》2014,36(5)

地下储油罐变位影响罐容表正常标定．针对罐内油位高度的不同工况,基于微元法思想建立了储油罐变位识别的数学模型,并利用最小二乘法原理,结合MATLAB软件,计算出变位参数α＝2.12°,β＝4.06°,实现了罐容表的准确标定．通过模型分析,表明该模型是合理的,稳定性较好,且对罐容表的标定比现有数学模型更为准确,可在类似形体中推广应用．  相似文献   

基于最优投影逼近法的X射线硬化校正     

邓娜  江长森 《西南大学学报(自然科学版)》2014,36(5)

射束硬化是导致CT重建图像下降的物理原因之一。该文分析了射束硬化校正的常用方法,比如线性化方法、基于原始投影正弦图的校正方法,并在此基础上提出了一种适用于非圆形检测对象的最优投影逼近法。该方法将射线穿透距离最短的扫描角度作为最优投影角度,将该角度下的原始投影作为校正标准,并建立硬化校正方程,通过牛顿迭代法解得各个投影角度下的校正值。实验结果表明,采用本文方法进行硬化校正后,由射束硬化引起的杯状伪影得到较好地抑制。该方法具有自适应性,执行效率高,并且可以推广到多材质扫描对象的硬化校正。  相似文献   

家畜生殖激素研究   总被引：3，自引：0，他引：3  

孙晓萍  杨博辉  程胜利  刘建斌  郎侠 《甘肃畜牧兽医》2007,37(5):39-42

1 促黄体素(LH)在家畜体内不同生理阶段代谢规律 LH的分泌受丘脑下部促黄体素释放激素(LH-RH)的调节,并在很大程度上受动物性腺激素的反馈调节.在家畜性发育过程中,刚出生的仔畜血液中LH保持在较高的浓度,随后急剧下降,在达到性成熟之前,有两次上升,不同的品种上升的时间不一致.  相似文献   

Pyramiding genes affecting sprouting resistance in Rye by means of marker assisted selection     

Marta?Twardowska  Piotr?Masoj?Email author  Pawe??Milczarski 《Euphytica》2005,143(3):257-260

The 541 × Ot1-3 intercross population and bulked segregant analysis (BSA) were used to search for molecular markers linked to genes underlying sprouting and alpha-amylase activity. Six RAPD markers showing association with studied traits were tested for their potential effectiveness in selecting sprouting resistant genotypes. It was shown that although individual effects of markers were not high, their accumulation in one genotype gives substantial increase in sprouting resistance.  相似文献