scholarly journals No environmental effect on vaccine-induced reduced growth in Atlantic salmon Salmo salar smolts

2020 ◽  
Vol 12 ◽  
pp. 327-338
Author(s):  
TWK Fraser ◽  
PG Fjelldal ◽  
I Sommerset ◽  
T Søfteland ◽  
O Høstmark ◽  
...  

Oil-adjuvanted vaccines reduce long-term growth in farmed Atlantic salmon Salmo salar, possibly via an increase in metabolic rate due to the energetic demands of the immune system. We tested this hypothesis by comparing sham-vaccinated to vaccinated smolts (total n = 2096, ca. 80 g) under different scenarios of water temperature (12 vs. 17°C, n = 1048 per temperature) and oxygen (O2) saturation (60, 70, 80, and 100%, n = 524 per O2 saturation level) in order to manipulate metabolic rate and O2 availability. We expected a more severe vaccination effect under conditions of high water temperature and low O2 saturation. Groups were kept in duplicate tanks under controlled temperature and hypoxia conditions for 7 wk post-vaccination before being transferred to uncontrolled common-garden natural conditions for 5 mo in a sea-cage. Body mass and length were recorded at the initiation and end of the controlled and uncontrolled environmental conditions. Vaccination and low O2 saturation at 17°C significantly reduced body mass (13 and 3% through vaccination and 9 and 20% through 60% O2 saturation at the end of the tank and sea-cage periods, respectively). However, there was no interaction between vaccination, temperature, and O2 saturation at the end of the tank or sea-cage period, lending no support to our hypothesis. A secondary observation was that emaciated ‘loser’ fish were mainly associated with the 17°C and low (mainly 60%) O2 saturation treatment. In conclusion, although vaccination led to a reduction in body mass, this effect was not influenced by environmental conditions expected to alter metabolic rate.

2013 ◽  
Vol 70 (7) ◽  
pp. 1072-1081 ◽  
Author(s):  
David Beauregard ◽  
Eva Enders ◽  
Daniel Boisclair

Fish that inhabit rivers may experience important daily fluctuations in water temperature. Bioenergetic models have the potential to simulate the effects of such fluctuations on fish growth; however, bioenergetic components are traditionally modeled using fish kept at constant water temperatures. This study tested the hypothesis that circadian fluctuations in water temperature increase the standard metabolic rate of fish. The standard metabolic rate of Atlantic salmon parr (Salmo salar; 5.96–36.20 g wet blotted mass) estimated at 20 ± 0.5 °C was 25% to 32% lower for fish held at a relatively constant water temperature (20.2 ± 0.5 °C) than for fish maintained under fluctuating thermal regimes (19.8 ± 2.0 °C; 19.5 ± 3.0 °C). This study suggests that a rise in standard metabolic rate may explain how temperature fluctuations affect fish growth. It also indicates that the traditional approach used to estimate and model components of the bioenergetic equation may substantially underestimate the standard metabolic rate of fish that are subjected to such fluctuations.


2005 ◽  
Vol 62 (5) ◽  
pp. 1079-1089 ◽  
Author(s):  
Eva C Enders ◽  
Daniel Boisclair ◽  
André G Roy

Juvenile Atlantic salmon (Salmo salar) live in rivers characterized by highly turbulent flows. In these environments, flow turbulence is associated with a wide range of instantaneous flow velocities, which may affect the energetic costs of habitat utilization of juvenile Atlantic salmon. The purpose of our work was to develop a swimming costs model for juvenile Atlantic salmon that especially accounts for the effects of velocity fluctuations in turbulent environments. We estimated the total swimming costs of fish in a respirometer in which we produced five turbulent flow conditions, each characterized by a mean and a standard deviation of flow. Respirometry experiments were conducted at water temperatures of 10, 15, and 20 °C with fish ranging in size between 4.3 and 17.6 g at three mean flow velocities (18, 23, and 40 cm·s–1) and three standard deviations of flow velocity (5, 8, and 10 cm·s–1). Our results confirmed that total swimming costs increased with an increase of water temperature, body mass, mean flow velocity, and standard deviation of flow velocity (R2 = 0.93). Water temperature, body mass, mean flow velocity, and standard deviation of flow velocity contributed respectively 2%, 31%, 46%, and 14% to the explained variation in total swimming costs.


2003 ◽  
Vol 60 (11) ◽  
pp. 1386-1397 ◽  
Author(s):  
Philippe Girard ◽  
Daniel Boisclair ◽  
Michel Leclerc

We tested the validity of the predictions made by a habitat probabilistic index (HPI) developed using a description of the physical conditions (depth, flow velocity, grain size) used and avoided by parrs during days of different cloudiness. Thirteen surveys were designed to estimate the number and the distribution of parrs actively foraging within a 300-m reach of a river. During these surveys, the number of parrs actively foraging ranged from 12 to 118, cloud cover ranged from 5% to 100%, and water temperature ranged from 16.5 °C to 21.7 °C. The number of parrs actively foraging was negatively related to cloud cover (r2 = 0.44 to 0.88) but was independent of water temperature. HPI models developed under low (<33%) and intermediate (34–67%) cloud cover explained 82% to 98% of the local variations of fish density. The HPI model developed under high cloud cover (67–100%) was unable to predict fish distribution observed during cloudy days. Our results suggest that HPI models developed when cloudiness is >67% may have a limited predictive power.


1979 ◽  
Vol 36 (2) ◽  
pp. 132-140 ◽  
Author(s):  
Philip E. K. Symons

Smolt production at different egg deposition densities is estimated from data on survival rates and space requirements of juvenile Atlantic salmon (Salmo salar) reported in the literature. Average maximum production of smolts is estimated to be approximately 5/100 m2 for 2+ smolts, 2/100 m2 for 3+ smolts, and 1/100 m2 for 4+ smolts. Minimum egg depositions recommended for production of these numbers of smolts are 220/100 m2, 165–220/100 m2, and 80/100 m2 for each age of smolts, respectively. The escapement of adults required to produce these depositions must be estimated from observed average weights of returning females and a reported fecundity of Atlantic salmon between 1650 and 1760 eggs/kg of female. With the exception of Ungava rivers, average smolt age in any particular river can be estimated from the number of days per year on which water temperature reaches or exceeds 7 °C. Key words: fishery resources, fishery management, production (biological), escapement, survival, game fish, freshwater fish, rivers


2015 ◽  
Vol 46 (3) ◽  
pp. 267-271 ◽  
Author(s):  
N. N. Nemova ◽  
Z. A. Nefedova ◽  
S. A. Murzina ◽  
A. E. Veselov ◽  
P. O. Ripatti ◽  
...  

2010 ◽  
Vol 105 (7) ◽  
pp. 1012-1025 ◽  
Author(s):  
Vasileios Karalazos ◽  
Eldar Å. Bendiksen ◽  
James R. Dick ◽  
Douglas R. Tocher ◽  
John Gordon Bell

A factorial, two-way, experimental design was used for this 10-week nutritional trial, aiming to elucidate the interactive effects of decreasing dietary protein:lipid level and substitution of fish oil (FO) with rapeseed oil (RO) on tissue fatty acid (FA) composition and metabolism of large Atlantic salmon (Salmo salar L.) reared at high water temperatures (sub-optimal, summer temperatures: 11·6°C). The six experimental diets were isoenergetic and formulated to include either FO or RO (60 % of the added oil) at three dietary protein:lipid levels, specifically (1) 350 g/kg protein and 350 g/kg lipid, (2) 330 g/kg protein and 360 g/kg lipid, (3) 290 g/kg protein and 380 g/kg lipid. Final weight, specific growth rate and thermal growth coefficient were positively affected by the dietary RO inclusion at the expense of FO, while no significant effects were seen on growth due to the decreasing protein level. The oil source had a significant effect on muscle and liver FA composition. However, the changes in muscle and liver FA indicate selective utilisation or retention of individual FA and moderate reductions in tissue EPA and DHA. Pyloric caeca phospholipid FA composition was significantly affected by the two factors and, in some cases, significant interactions were also revealed. Liver and red muscle β-oxidation capacities were significantly increased due to RO inclusion, while an interactive effect of protein level and oil source was shown for white muscle β-oxidation capacity. The results could explain, at least partially, the better performance that was shown for the RO groups and the enhanced protein-sparing effect.


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