Memorias de investigación
Communications at congresses:
SHORT-TERM FASTING AND WELFARE PRIOR TO SLAUGHTER IN RAINBOW TROUT, ONCORHYNCHUS MYKISS
Year:2013

Research Areas
  • Aquaculture

Information
Abstract
Fasting fish before slaughter is a common practise in aquaculture but it is not clear how long rainbow trout can be starved before suffering unnecessary stress, nor at what moment of the day slaughter is least stressful. We fasted 90 rainbow trout (Oncorhynchus mykiss; initial average weight 215.0±22.6 g) for 24, 48 and 72 hours (19.5, 38.8 and 58.0 ºC days) and slaughtered them in the morning (08h00), afternoon (14h00) and at night (20h00) to observe the effect of fasting duration and slaughter time on welfare indicators, including plasma cortisol, glucose and lactate concentrations as well as hematocrit and leucocyte count. The values of the fasted fish were compared with 90 control fish kept under similar conditions but not fasted. Body weight was not significantly different between fasted fish and controls during the trial, but body condition coefficient (live weight/length3) was higher in fed fish. The relative weight of the gut was higher in control trout after 24 of fasting, indicating that the gut had emptied after 24 h. Cortisol levels were similar between fasted and control fish but lowest in fish slaughtered at 20h00. However, glucose and lactate concentrations in plasma were similar. Hematocrit values were also normal and similar between fasted fish and controls throughout the experiment, but leucocyte count was significantly lower in fasted fish by day three. These results suggest that rainbow trout can cope with fasting up to three days (58.0 ºC days) prior to slaughter and that their welfare is not seriously compromised. Slaughtering at night, when cortisol levels are lower, may help to avoid excessive stress.
International
Si
Congress
UFAW Animal Welfare Conference
960
Place
Barcelona, España
Reviewers
Si
ISBN/ISSN
Start Date
04/07/2013
End Date
05/07/2013
From page
To page
Participants

Research Group, Departaments and Institutes related
  • Creador: Grupo de Investigación: Producción Animal
  • Grupo de Investigación: Hidrobiología