scholarly journals A Multidisciplinary Approach Evaluating Soybean Meal-Induced Enteritis in Rainbow Trout Oncorhynchus mykiss

Fishes ◽  
2022 ◽  
Vol 7 (1) ◽  
pp. 22
Author(s):  
Henrike Seibel ◽  
Elvis Chikwati ◽  
Carsten Schulz ◽  
Alexander Rebl

This study evaluated a diverse range of markers of feeding stress to obtain a more precise assessment of the welfare of rainbow trout in relation to inadequate husbandry conditions. A feeding stress model based on dietary soybean meal was employed to identify suitable minimally invasive “classical” stress markers, together with molecular signatures. In a 56-day feeding experiment, rainbow trout were fed diets containing different levels of soybean meal. The impact of these different soybean meal diets on rainbow trout was assessed by water quality analyses, clinical health observations, classic growth and performance parameters, gut histopathology, blood-parameter measurements and multigene-expression profiling in RNA from whole blood. Soybean meal-induced enteritis was manifested phenotypically by an inflammatory reaction in the posterior section of the intestine and by diarrhoea in some trout. These inflammatory changes were associated with decreased supranuclear vacuolation. The haematocrit values and the levels of plasma cortisol and circulating lymphocytes in the blood were increased in trout that had consumed high amounts of SBM. Notably, the increased haematocrit depended significantly on the bodyweight of the individual trout. The transcript levels of certain genes (e.g., MAP3K1, LYG, NOD1, STAT1 and HSP90AB) emerged as potentially useful indicators in the blood of rainbow trout providing valuable information about inadequate nutrition. The expression-profiling findings provide a basis for improved, minimally invasive monitoring of feeding regimens in trout farming and may stimulate the development of practical detection devices for innovative aquaculture operations.

1995 ◽  
Vol 31 (10) ◽  
pp. 219-223 ◽  
Author(s):  
M. Tomec ◽  
Z. Teskeredžic ◽  
E. Teskeredžic ◽  
M. Hacmanjek ◽  
E. McLean

Juvenile rainbow trout, Oncorhynchus mykiss, maintained under commercial conditions, were subjected to four different feeding regimes. Duplicate groups of fish were fed to satiation 3 times/d for either 7, 3, 2 or 1 d/wk over a 10 wk period. At the end of the trial, evaluations were made of group growth performance, body composition, and feed conversion efficiency (FCE). At the end of the experiment, no differences were discerned between fish fed either daily or 3 times/wk with respect to growth, FCE or body composition. Animals placed upon the two lowest rations were significantly smaller (P<0.05) than those fed daily and exhibited decreased condition factors and body lipid levels (P<0.05) and increased moisture content (P<0.05). Food conversion was least efficient in those fish provided the largest ration.


2018 ◽  
Vol 13 (2) ◽  
Author(s):  
Naji J. Touma ◽  
Darren T. Beiko ◽  
Andrew E. MacNeily ◽  
Michael J. Leveridge

Introduction: Many factors impact the performance of graduating residents on certification exams. It is thought that most factors are related to the individual candidate’s ability, motivation, and work ethic. Less understood, however, is whether a training program has any impact on the preparation and performance of its graduates on certification exams. We present 20 years of results of a national preparatory exam that all graduating residents complete about three months before the Royal College of Physicians and Surgeons of Canada (RCPSC) qualifying urology exam. This exam, known colloquially as QUEST, aims to simulate the RCPSC exam with written and oral components. We aimed to analyze the impact of a training program on the performance of its residents. Methods: A retrospective review of exam results from 1997–2016 was conducted. During that time, 495 candidates from all 12 Canadian urology training programs undertook the exam. The performance of graduating residents from each individual program was grouped together for any given year. The different programs were anonymized, as the aim of this study is to assess the impact of a training program and not to rate the different programs. Statistical analysis using one-way ANOVA was conducted. Results: All training programs fall within one standard deviation of the mean for the written component, the oral component, and the overall score. The residents of four training programs had statistically better scores than the overall mean of the written component. The residents of three out of these four training programs also had statistically better scores than the overall mean of the oral component and the overall results of the exam. Conclusions: Most Canadian training programs prepare their residents adequately for this simulated certification exam in urology. However, there are some training programs that consistently prepare graduating residents to outperform their peers.


1990 ◽  
Vol 68 (5) ◽  
pp. 969-973 ◽  
Author(s):  
J. M. Shrimpton ◽  
D. J. Randall ◽  
L. E. Fidler

We examined the effects of swim bladder overinflation associated with dissolved gas supersaturation on rainbow trout (Oncorhynchus mykiss). The change in swim bladder volume with increased swim bladder pressure was measured in fish subjected to a decrease in ambient pressure. An expansion of swim bladder volume occurs that is related to the excess swim bladder pressure. The volume change results in a decrease in density and positive buoyancy in the fish. Small fish are adversely affected when exposed to gas supersaturated water because of the high swim bladder pressure required to force gas out the pneumatic duct. Changes in behaviour and depth distribution of fish held in gas supersaturated water were measured in a 2 m deep observation column. A large change in density caused small fish to increase depth and compensate for the swim bladder expansion. Although swim bladder inflation occurs for all sizes of trout held in gas supersaturated water, the impact is greatest for small fish and they must compensate by seeking depth. However, adequate depth to compensate for positive buoyancy may not always exist. In such a case, fish must swim continuously in a head down position to overcome excess buoyancy. The power necessary for a fish to swim with an overinflated swim bladder is greatest for small fish that show the largest change in density.


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