Assessing the suitability of a partial water reuse system for rearing juvenile Chinook salmon for stocking in Washington State

To assess the suitability of water reuse technology for raising Pacific salmon Oncorhynchus spp. for stocking purposes, fish health and welfare were compared between two groups of juvenile Chinook salmon O. tshawytscha from the same spawn: one group was reared in a pilot partial water reuse system (circular tanks), and the other group was reared in a flow-through raceway. This observational study was carried out over a 21-week period in Washington State. Reuse and raceway fish were sampled repeatedly for pathogen screening and histopathology; fin erosion and whole-blood characteristics were also evaluated. By the study's end, no listed pathogens were isolated from either cohort, and survival was 99.3% and 99.0% in the reuse and raceway groups, respectively. Condition factor was 1.28 in raceway fish and 1.14 in reuse fish; this difference may have been attributable to occasional differences in feeding rates between the cohorts. Fin indices (i.e., length of the longest dorsal or caudal fin ray, standardized by fork length) were lower in reuse fish than in raceway fish, but fin erosion was not grossly apparent in either cohort. The most consistent histological lesion was gill epithelial hypertrophy in reuse fish; however, blood analyses did not suggest any corresponding physiological imbalances. Overall, results suggest that water reuse technology can be employed in rearing juvenile anadromous salmonids for stocking purposes.     

Relation of Water Temperature to Bacterial Cold-Water Disease in Coho Salmon,Chinook Salmon,and Rainbow Trout

Abstract

The effect of water temperature on the progress of experimentally induced Cytophaga psychrophila infection was investigated in juveniles of coho salmon Oncorhynchus kisutch, chinook salmon O. tshawytscha, and rainbow trout O. mykiss (formerly Salmo gairdneri). A virulent strain of C. psychrophila was administered to fish by subcutaneous injection. Infected fish were held in tanks containing pathogen-free well water at temperatures ranging from 3 to 23°C. Mean times from infection to death of the fish were shortest at 12–15°C, which were the temperatures associated with the shortest time for doubling the population of this bacterium in vitro. Juvenile steelhead (anadromous rainbow trout) injected with viable C. psychrophila cells and held in 22°C water did not become diseased.     

An Evaluation of the Influence of Stock Origin and Out-migration History on the Disease Susceptibility and Survival of Juvenile Chinook Salmon

Abstract

Various methods have been developed to mitigate the adverse effects of the Federal Columbia River Power System on juvenile Pacific salmon out-migrating through the Columbia River basin. In this study, we found that hatchery-reared spring Chinook salmon Oncorhynchus tshawytscha in the river are in varying degrees of health, which may affect delayed mortality and the assessment of the effectiveness of management actions to recover listed stocks (e.g., barging fish downstream versus leaving fish in the river). A laboratory disease challenge with Listonella anguillarum was completed on fish from Rapid River Hatchery and Dworshak National Fish Hatchery (NFH) with different out-migration histories: (1) transported by barge, (2) removed from the river before barging, or (3) left to travel in-river. Barged fish from Rapid River Hatchery experienced less mortality than fish from Dworshak NFH. No statistical differences were found between the hatcheries with fish that had in-river out-migration histories. We suggest that the stressors and low survival associated with out-migration through the hydropower system eliminated any differences that could have been present. However, 18–25% of the fish that were barged or collected before barging died in the laboratory before the disease challenge, compared with less than 2% of those that traveled in-river. Owing to disproportionate prechallenge mortality, the disease-challenged populations may have been biased; thus, they were also considered together with the prechallenge mortalities. The synthesis of prechallenge and disease-challenged mortalities and health characteristics evaluated during out-migration indicated that the benefit of barging was not consistent between the hatcheries. This finding agrees with adult survival and delayed mortality estimates for the individual hatcheries determined from adult returns. The results suggest that the health status of fish and their history before entering the hydropower system (hatchery of origin and out-migration path) are critical variables affecting the conclusions drawn from studies that evaluate mitigation strategies.

Received November 18, 2009; accepted January 6, 2011     

Ichthyophoniasis: An Emerging Disease of Chinook Salmon in the Yukon River

Abstract

Before 1985, Ichthyophonus was unreported among Pacific salmon Oncorhynchus spp. from the Yukon River; now it infects more than 40% of returning adult Chinook salmon O. tshawytscha. Overall infection prevalence reached about 45% in the Yukon River and about 30% in the Tanana River between 1999 and 2003. Mean infection prevalence was greater in females than males in the main-stem Yukon River during each of the 5 years of the study, but the infection prevalence in males increased each year until the difference was no longer significant. Clinical signs of ichthyophoniasis (presence of visible punctate white lesions in internal organs) were least at the mouth of the Yukon River (～10%) but increased to 29% when fish reached the middle Yukon River and was 22% at the upper Tanana River. However, clinical signs increased each year from 7% in 1999 to 27% in 2003 at the mouth of the river. As fish approached the upper reaches of the Yukon River (Canada) and the spawning areas of the Chena and Salcha rivers (Alaska), infection prevalence dropped significantly to less than 15% in females on the Yukon River and less than 10% for both sexes in the Chena and Salcha rivers, presumably because of mortality among infected prespawn fish. Age was not a factor in infection prevalence, nor was the position of fish within the run. The source of infection was not determined, but Ichthyophonus was not found in 400 Pacific herring Clupea pallasi from the Bering Sea or in 120 outmigrating juvenile Chinook salmon from two drainages in Alaska and Canada. Freshwater burbot Lota lota from the middle Yukon River were subclinically infected with Ichthyophonus, but the origin and relationship of this agent to the Chinook salmon isolate is unknown.     

Survival Rates of Out-Migrating Yearling Chinook Salmon in the Lower Columbia River and Plume after Exposure to Gas-Supersaturated Water

In 2011, unusually high flows caused total dissolved gas (TDG) levels in the Columbia River, USA, to escalate well above the 120% regulatory limit that was imposed to prevent harmful impacts to aquatic organisms. After observing gas bubble trauma (GBT) in dead yearling Chinook Salmon Oncorhynchus tshawytscha (smolts) held in tanks, we compared estimated survival rates of acoustic-tagged in-river-migrating (IR) and transported (TR) smolts that were released below Bonneville Dam prior to and during the period of elevated TDG (>120%). The log odds of estimated daily survival in the lower river and plume was significantly lower for IR smolts that were released during elevated TDG (maximum possible exposure = 134%) than for IR smolts released when TDG was less than 120%. The TR smolts that were released 10–13 km below Bonneville Dam during elevated TDG had lower maximum possible exposure levels (126% TDG), and the log odds of estimated daily survival in the lower river and plume did not differ from that of TR smolts released when TDG was less than 120%. Direct mortality due to GBT is probably reduced in natural settings relative to laboratory experiments because smolts can move to deeper water, where pressure keeps gasses in solution, and can migrate downstream of the spillway, where TDG levels decrease as the river returns to equilibrium with the atmosphere. However, initially nonlethal GBT may reduce survival rates by increasing smolt susceptibility to predation and infection. Although our findings are limited by the observational nature of the study, our analysis is the first direct assessment of gas supersaturation’s potential influence on survival of free-ranging smolts in the river and coastal ocean below a large dam. Experiments using simultaneous releases of control and gas-exposed groups are warranted and should consider the possibility that the chronic effects of TDG exposure on survival are important and persist into the early marine period.

Received October 5, 2015; accepted August 18, 2016 Published online October 24, 2016     

Monoclonal Antibody-Based Analysis of the Renibacterium salmoninarum p57 Protein in Spawning Chinook and Coho Salmon

Abstract

Renibacterium salmoninarum, causative agent of bacterial kidney disease of salmonid fish, produces large amounts of soluble proteins during infection and broth culture. An enzyme-linked immunosorbent assay (ELISA) based on monoclonal antibodies was developed for the precise quantification of p57, a major component of these proteins. Kidney, spleen, blood, and reproductive fluids of adult Pacific salmon Oncorhynchus spp. were examined by means of the assay. Kidney and spleen harbored the highest concentrations of this antigen. In the populations of returning salmon tested, 5–25% of the fish had p57 concentrations above a baseline level of 3 ng antigenig tissue, and antigen concentrations as high as 200 μg/g tissue were detected in kidneys of individual fish. The ELISA was compared to direct fluorescent antibody analysis, in which rabbit anti-R. salmoninarum antiserum was used to identify infected fish. There was 99% agreement (199 of 201 examined fish) between the two methods. Western blot analysis was used to demonstrate that antigenic proteins present in infected fish were similar to those seen from antigen prepared from broth culture of R. salmoninarum, although less degradation of p57 appears to occur in vivo.     

Survey of Pathogens in Hatchery Chinook Salmon with Different Out-Migration Histories through the Snake and Columbia Rivers

The operation of the Federal Columbia River Power System (FCRPS) has negatively affected threatened and endangered salmonid populations in the Pacific Northwest. Barging Snake River spring Chinook salmon Oncorhynchus tshawytscha through the FCRPS is one effort to mitigate the effect of the hydrosystem on juvenile salmon out-migration. However, little is known about the occurrence and transmission of infectious agents in barged juvenile salmon relative to juvenile salmon that remain in-river to navigate to the ocean. We conducted a survey of hatchery-reared spring Chinook salmon at various points along their out-migration path as they left their natal hatcheries and either migrated in-river or were barged through the FCRPS. Salmon kidneys were screened by polymerase chain reaction for nine pathogens and one family of water molds. Eight pathogens were detected; the most prevalent were Renibacterium salmoninarum and infectious hematopoietic necrosis virus. Species in the family Saprolegniaceae were also commonly detected. Pathogen prevalence was significantly greater in fish that were barged through the FCRPS than in fish left to out-migrate in-river. These results suggest that the transmission of infectious agents to susceptible juvenile salmon occurs during the barging process. Therefore, management activities that reduce pathogen exposure during barging may increase the survival of juvenile Chinook salmon after they are released.

Received May 27, 2010; accepted January 17, 2011     

不同放牧率对混播草地牧草与羔羊生产的影响

通过三种放牧率对混播草地牧草和羔羊生产的影响进行了研究。结果表明，随着放牧率的增加，牧草产量、叶面积指数明显下降（Ｐ＜０．０５）并使茎叶比显著减少（Ｐ＜０．０５）。放牧率的增大，羔羊个体生产速度显著降低（Ｐ＜０．０１），单位面积的畜产品产量依次为中组＞低组＞高组。并得出羔羊生长量与放牧强度及采食牧草干物质量存在密切关系，同时放牧率影响肉的品质，放牧率不同，草地系统生物学转化效率中组比低、高组高，且草地生产能力最大。由此得出，混播草地以中等放牧率为最佳。     

Hemolysis Associated With Water Administration Using a Nipple Bottle for Human Infants in Juvenile Pygmy Goats

A 4-month-old, 6.8-kg, castrated male pygmy goat was examined for recurrent episodic fever and red urine of 7 days' duration. A second, 3-month-old, 7-kg, intact female pygmy goat was presented for similar clinical signs. The red discoloration of the urine in each case was determined to be due to hemolysis with subsequent hemoglobinuria. In both cases, hemolysis and hemoglobinuria were closely associated with the goats consuming large volumes of water from a human infant's nipple bottle. A diagnosis of water intoxication-induced hemolysis and hemoglobinuria was made. Episodes of hemoglobinuria in the first case were consistently associated with dilute (specific gravity < 1.010) urine. Water intoxication has been associated with bottle-feeding in human infants and is also widely reported in human psychiatric patients. The small erythrocytes in goats appear to be the most sensitive of the domestic species to hypotonicity-induced hemolysis.     

The use of web-conferencing in the college of veterinary medicine at Washington State University

This article presents a review of Web-conferencing and evaluation data from veterinary students and animal owners participating in Web-conference events. Web-conferencing allowed for high-fidelity transmission of images and adequate transmission of audio by off-site instructors. Geographically distributed participants found Web-conference software easy to set up and to use. Participant satisfaction varied with the type of participant; the highest satisfaction rate was from pet owners and the lowest from veterinary students in a core course.     

浅述不同水质用于超声波加湿对小蚕饲育环境菌落数的影响

1 问题的提出 近年来,养蚕农户对小蚕共育的设施要求越来越高,温湿控制器在小蚕共育中逐渐普及应用.目前市场上温湿控制器生产厂家众多,加温装置大都使用PTC电热陶瓷为热源,实践证明PTC电热陶瓷加温效果好,安全节能.加湿装置主要有冷加湿与热加湿两大类:冷加湿分为超声波加湿和湿帘式加湿;热加湿分为热膜式和电极式.     

新型蚕用环境控制器小蚕共育试验初报

为了增强蚕儿体质,提高单产,进行小蚕共育是一项重要技术.目前,在我省小蚕饲育过程中普遍采用修建专用共育室,使用地火笼或煤砖炉调整蚕室温度,利用人工洒水调整湿度的方法控制温、湿度:但该方法及易出现环境温度骤高骤低、湿度不易掌握等缺点,同时升温烧煤产生的二氧化硫、一氧化碳等有害气体直接影响蚕儿的发育和生长.     

Perceptions of the human-animal bond in veterinary education of veterinarians in Washington State: structured versus experiential learning

RATIONALE FOR THE STUDY: The purpose of this research was to describe Washington private practitioners' beliefs about how the Human-Animal Bond (HAB) should be addressed in DVM curricula and continuing education. METHODOLOGY: 1,602 Washington veterinarians in private practice were asked to participate in an online survey that addressed the importance of HAB and of DVM/post-DVM HAB education. RESULTS AND CONCLUSIONS: The response rate was 25.9% (415/1,602). Eighty-one percent (334/412) of respondents indicated that the HAB was important to their decisions to become veterinarians. The HAB was more important to the most recent graduates than to earliest graduates and to females than to males. Forty-four percent (184/415) of respondents considered mentoring to be the best way to learn about the HAB while in veterinary school. Of the 40% (165/415) of respondents who indicated that their veterinary schools offered structured learning on the HAB, 89% (145/163) said they had participated in it. Seven percent (29/415) indicated that entry-level veterinarians were very prepared to identify and facilitate the HAB, while 54% (224/415) said that they were somewhat prepared. Only 32% (131/415) had participated in any HAB structured learning since having started practicing, and the earliest graduates were twice as likely to have participated as the most recent graduates. More than half (55%, 223/407) disagreed or strongly disagreed that post-DVM, the best way to learn about the HAB is through structured learning. However, 83% (342/414) agreed that continuing-education credits should be given for HAB classes. Eighty-six percent (358/414) supported additional HAB research. Ninety-seven percent (402/414) agreed that the best way to learn about the HAB is through experience. These results suggest that veterinarians do not value HAB structured learning as much as experiential learning and that they are not very confident in recent graduates' abilities regarding the HAB. We propose HAB structured learning in the first three years of DVM education, complemented by the incorporation of the HAB into clinical rotations and post-DVM continuing education.     

三种饲料原料对大蚕人工饲料育的影响

本实验通过探讨家蚕人工饲料中水分、豆粕、蔗糖三个因素对大蚕饲养成绩的影响,以期为大蚕低成本饲料的开发提供依据。粉体干饲料中添加1.9倍水能提高家蚕幼虫体重、茧层量等指标;添加膨化豆粕比普通豆粕更能提高养蚕成绩,其中添加45%膨化豆粕相对比较经济;添加蔗糖能促进蚕蛹体重增加,但对于茧层量影响不大。     

养猪小区粪便资源化处理工艺设计

影响我国养猪小区健康发展的关键问题是养猪小区的环境控制,降水、污水、粪便混合排放,加剧了养猪小区的环境污染,使粪便资源化处理更加困难。根据现代养猪生产工艺流程,利用工程技术手段,设计了一个现代化示范型养猪小区粪便资源化处理工艺,首先解决天然降水与污水混合排放问题,其次实现污水与粪便有效分离,第三步通过充氧发酵、搅拌干燥最终实现养猪小区粪便资源化开发利用,解决捆扰我国养猪小区健康发展的环境控制问题。     

养猪小区粪便资源化处理工艺设计

影响我国养猪小区健康发展的关键问题是养猪小区的环境控制,降水、污水、粪便混合排放,加剧了养猪小区的环境污染,使粪便资源化处理更加困难。根据现代养猪生产工艺流程,利用工程技术手段,设计了一个现代化示范型养猪小区粪便资源化处理工艺,首先解决天然降水与污水混合排放问题,其次实现污水与粪便有效分离,第三步通过充氧发酵、搅拌干燥最终实现养猪小区粪便资源化开发利用,解决捆扰我国养猪小区健康发展的环境控制问题。     

不同季节与饲养密度条件下发酵床养殖对肉鸭生产性能的影响

试验系统研究不同季节(春、夏、秋、冬)与养殖密度条件下(2.7、3.6、4.4只/m2)发酵床养殖对樱桃谷肉鸭生产性能的影响。结果表明:相比较传统的水养模式,不同季节发酵床养鸭均可显著改善肉鸭的成活率、出栏重和饲料报酬(P0.05);夏季肉鸭成活率、出栏重与采食量均为最低,秋季肉鸭成活率、出栏重与总料重比为最优;不同饲养密度条件下,发酵床养鸭较传统水养均可显著提高肉鸭成活率和料重比(P0.05),且肉鸭生产性能随着养殖密度的降低而提高。结论:不同季节和饲养密度条件下,发酵床养殖均可改善肉鸭部分生产性能,肉鸭生产性能随饲养密度降低而改善。     

浅谈水利高校节水循环系统

我国水资源贫乏,时空分布不均,与我国经济发展、民生需求的矛盾日益突出。考虑现今与未来的发展,树立节水意识、提高水资源的利用率迫在眉睫。而水利高校节水循环系统的建立能适当地缓解这个重大问题,并且成本较低,具有一定的长远效应。     

Suitability of the cranial portion of the vagina as a site for measurement of intra-abdominal pressure variations in dogs

OBJECTIVE: To determine whether the cranial portion of the vagina of dogs is a suitable site for measuring intra-abdominal pressure during cystometry. ANIMALS: 16 bitches (8 sexually intact and 8 spayed). PROCEDURE: 2 types of vaginal catheters were used to measure intra-abdominal pressure changes in anesthetized dogs. Catheters were inserted in the rectum and cranial portion of the vagina. RESULTS: Intra-abdominal pressure variations were detected with greater magnitude in the rectum than the cranial portion of the vagina, regardless of type of catheter used and reproductive status (sexually intact vs spayed) of the dogs. CONCLUSIONS AND CLINICAL RELEVANCE: The rectum was the better site for measuring intra-abdominal pressure changes in female dogs. Measurement of intra-abdominal pressure with concomitant measurement of intravesical pressure to determine detrusor pressure during cystometry in female dogs is more reliably detected from the rectum than the cranial portion of the vagina.