Effects of stocking density and sustained aerobic exercise on growth, energetics and welfare of rainbow trout

David J. McKenzie, Erik Höglund, A. Dupont-Prinet, Bodil Katrine Larsen, Peter Vilhelm Skov, Per Bovbjerg Pedersen, Alfred Jokumsen

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Two stocking densities, “low” (L, between ~19 and ~25 kgm−3) and “high” (H, between ~75 and ~100 kgm−3) were compared for effects on specific growth rate (SGR), feed conversion, energetics and welfare of rainbow trout reared at 14 °C either in static water (S) or swimming in a gentle current of ~0.9 bodylengths s−1 (C). Trout (initialmass ~110 g)were reared for 9 weeks in circular tanks (volume 0.6 m3), in triplicate of four conditions (LS, LC, HS, HC). Fish were fed ad-libitum daily; waste pellets were swirl-collected at the outflow to calculate
feed intake. SGR was measured each three weeks for the last six weeks of the trial. The tanks functioned as intermittent-stopped flow respirometers, to permit metabolic rate to be measured as instantaneous oxygen uptake once per hour. Mean (±SD) SGR was significantly lower at H than L (1.51±0.03 vs 1.44±0.04%
day−1, respectively, n=6) and lowest in HC. When compared over a similar interval of mass gain, H groups had approximately 25% higher metabolic rates than L, with the highest rates in the HC condition. As a result, fish in the H groups dissipated a greater amount of feed energy as metabolism and, across all groups, there was a direct negative relationship between the quantity of energy dissipated and their SGR. There was no evidence of a neuroendocrine stress response, plasma cortisol was around 1 ng ml−1 in all conditions. An acute crowding stress increased plasma cortisol to above 120 ng ml−1 in all groups, but C groups recovered to control levels within 8 h whereas S groups required 20 h. Respirometry on individuals revealed that H fish had approximately 14% higher metabolic rates than L fish, indicating that increased metabolic rate in rearing tanks was in part physiological. TheHgroups had approximately 15% lower critical swimming speeds than the L groups which, together with their raised metabolic rate, indicated a physiological impairment. Thus, high density
reduced SGR by raising energy dissipation, at least partially as a physiological response by the fish, although there was no evidence of an endocrine stress response. The only beneficial effect of C was in recovery from acute stress
Original languageEnglish
JournalAquaculture
Volume338-341
Pages (from-to)216-222
ISSN0044-8486
DOIs
Publication statusPublished - 2012

Cite this

McKenzie, David J. ; Höglund, Erik ; Dupont-Prinet, A. ; Larsen, Bodil Katrine ; Skov, Peter Vilhelm ; Pedersen, Per Bovbjerg ; Jokumsen, Alfred. / Effects of stocking density and sustained aerobic exercise on growth, energetics and welfare of rainbow trout. In: Aquaculture. 2012 ; Vol. 338-341. pp. 216-222.
@article{f513134b1d5a4926be6b6f67a00060e8,
title = "Effects of stocking density and sustained aerobic exercise on growth, energetics and welfare of rainbow trout",
abstract = "Two stocking densities, “low” (L, between ~19 and ~25 kgm−3) and “high” (H, between ~75 and ~100 kgm−3) were compared for effects on specific growth rate (SGR), feed conversion, energetics and welfare of rainbow trout reared at 14 °C either in static water (S) or swimming in a gentle current of ~0.9 bodylengths s−1 (C). Trout (initialmass ~110 g)were reared for 9 weeks in circular tanks (volume 0.6 m3), in triplicate of four conditions (LS, LC, HS, HC). Fish were fed ad-libitum daily; waste pellets were swirl-collected at the outflow to calculate feed intake. SGR was measured each three weeks for the last six weeks of the trial. The tanks functioned as intermittent-stopped flow respirometers, to permit metabolic rate to be measured as instantaneous oxygen uptake once per hour. Mean (±SD) SGR was significantly lower at H than L (1.51±0.03 vs 1.44±0.04{\%} day−1, respectively, n=6) and lowest in HC. When compared over a similar interval of mass gain, H groups had approximately 25{\%} higher metabolic rates than L, with the highest rates in the HC condition. As a result, fish in the H groups dissipated a greater amount of feed energy as metabolism and, across all groups, there was a direct negative relationship between the quantity of energy dissipated and their SGR. There was no evidence of a neuroendocrine stress response, plasma cortisol was around 1 ng ml−1 in all conditions. An acute crowding stress increased plasma cortisol to above 120 ng ml−1 in all groups, but C groups recovered to control levels within 8 h whereas S groups required 20 h. Respirometry on individuals revealed that H fish had approximately 14{\%} higher metabolic rates than L fish, indicating that increased metabolic rate in rearing tanks was in part physiological. TheHgroups had approximately 15{\%} lower critical swimming speeds than the L groups which, together with their raised metabolic rate, indicated a physiological impairment. Thus, high density reduced SGR by raising energy dissipation, at least partially as a physiological response by the fish, although there was no evidence of an endocrine stress response. The only beneficial effect of C was in recovery from acute stress",
author = "McKenzie, {David J.} and Erik H{\"o}glund and A. Dupont-Prinet and Larsen, {Bodil Katrine} and Skov, {Peter Vilhelm} and Pedersen, {Per Bovbjerg} and Alfred Jokumsen",
year = "2012",
doi = "10.1016/j.aquaculture.2012.01.020",
language = "English",
volume = "338-341",
pages = "216--222",
journal = "Aquaculture",
issn = "0044-8486",
publisher = "Elsevier",

}

Effects of stocking density and sustained aerobic exercise on growth, energetics and welfare of rainbow trout. / McKenzie, David J.; Höglund, Erik; Dupont-Prinet, A.; Larsen, Bodil Katrine; Skov, Peter Vilhelm; Pedersen, Per Bovbjerg; Jokumsen, Alfred.

In: Aquaculture, Vol. 338-341, 2012, p. 216-222.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Effects of stocking density and sustained aerobic exercise on growth, energetics and welfare of rainbow trout

AU - McKenzie, David J.

AU - Höglund, Erik

AU - Dupont-Prinet, A.

AU - Larsen, Bodil Katrine

AU - Skov, Peter Vilhelm

AU - Pedersen, Per Bovbjerg

AU - Jokumsen, Alfred

PY - 2012

Y1 - 2012

N2 - Two stocking densities, “low” (L, between ~19 and ~25 kgm−3) and “high” (H, between ~75 and ~100 kgm−3) were compared for effects on specific growth rate (SGR), feed conversion, energetics and welfare of rainbow trout reared at 14 °C either in static water (S) or swimming in a gentle current of ~0.9 bodylengths s−1 (C). Trout (initialmass ~110 g)were reared for 9 weeks in circular tanks (volume 0.6 m3), in triplicate of four conditions (LS, LC, HS, HC). Fish were fed ad-libitum daily; waste pellets were swirl-collected at the outflow to calculate feed intake. SGR was measured each three weeks for the last six weeks of the trial. The tanks functioned as intermittent-stopped flow respirometers, to permit metabolic rate to be measured as instantaneous oxygen uptake once per hour. Mean (±SD) SGR was significantly lower at H than L (1.51±0.03 vs 1.44±0.04% day−1, respectively, n=6) and lowest in HC. When compared over a similar interval of mass gain, H groups had approximately 25% higher metabolic rates than L, with the highest rates in the HC condition. As a result, fish in the H groups dissipated a greater amount of feed energy as metabolism and, across all groups, there was a direct negative relationship between the quantity of energy dissipated and their SGR. There was no evidence of a neuroendocrine stress response, plasma cortisol was around 1 ng ml−1 in all conditions. An acute crowding stress increased plasma cortisol to above 120 ng ml−1 in all groups, but C groups recovered to control levels within 8 h whereas S groups required 20 h. Respirometry on individuals revealed that H fish had approximately 14% higher metabolic rates than L fish, indicating that increased metabolic rate in rearing tanks was in part physiological. TheHgroups had approximately 15% lower critical swimming speeds than the L groups which, together with their raised metabolic rate, indicated a physiological impairment. Thus, high density reduced SGR by raising energy dissipation, at least partially as a physiological response by the fish, although there was no evidence of an endocrine stress response. The only beneficial effect of C was in recovery from acute stress

AB - Two stocking densities, “low” (L, between ~19 and ~25 kgm−3) and “high” (H, between ~75 and ~100 kgm−3) were compared for effects on specific growth rate (SGR), feed conversion, energetics and welfare of rainbow trout reared at 14 °C either in static water (S) or swimming in a gentle current of ~0.9 bodylengths s−1 (C). Trout (initialmass ~110 g)were reared for 9 weeks in circular tanks (volume 0.6 m3), in triplicate of four conditions (LS, LC, HS, HC). Fish were fed ad-libitum daily; waste pellets were swirl-collected at the outflow to calculate feed intake. SGR was measured each three weeks for the last six weeks of the trial. The tanks functioned as intermittent-stopped flow respirometers, to permit metabolic rate to be measured as instantaneous oxygen uptake once per hour. Mean (±SD) SGR was significantly lower at H than L (1.51±0.03 vs 1.44±0.04% day−1, respectively, n=6) and lowest in HC. When compared over a similar interval of mass gain, H groups had approximately 25% higher metabolic rates than L, with the highest rates in the HC condition. As a result, fish in the H groups dissipated a greater amount of feed energy as metabolism and, across all groups, there was a direct negative relationship between the quantity of energy dissipated and their SGR. There was no evidence of a neuroendocrine stress response, plasma cortisol was around 1 ng ml−1 in all conditions. An acute crowding stress increased plasma cortisol to above 120 ng ml−1 in all groups, but C groups recovered to control levels within 8 h whereas S groups required 20 h. Respirometry on individuals revealed that H fish had approximately 14% higher metabolic rates than L fish, indicating that increased metabolic rate in rearing tanks was in part physiological. TheHgroups had approximately 15% lower critical swimming speeds than the L groups which, together with their raised metabolic rate, indicated a physiological impairment. Thus, high density reduced SGR by raising energy dissipation, at least partially as a physiological response by the fish, although there was no evidence of an endocrine stress response. The only beneficial effect of C was in recovery from acute stress

U2 - 10.1016/j.aquaculture.2012.01.020

DO - 10.1016/j.aquaculture.2012.01.020

M3 - Journal article

VL - 338-341

SP - 216

EP - 222

JO - Aquaculture

JF - Aquaculture

SN - 0044-8486

ER -