107
The use of anaesthetics facilitates work at the research level and is required for
invasive studies, where cephalopods must be held immobile for extended periods
of time. Nonetheless, anaesthetics are also used to reduce the level of stress associated with such procedures. In addition, an overdose of anaesthetics is also routinely
used as an effective and humane mean of euthanizing fish, and similar procedures
are already in use for cephalopods. However, the correct assessment of anaesthesia,
analgesia and euthanasia agents is a key aspect to determine the best agents, and the
physiology-based methods used for fish still need to be validated in cephalopods.
It is also important that the study of effective agents should be performed using a
welfare-based approach and this requires the development of new methods to accomplish this mission in the most ethical and humane way as possible. Studies to
determine a given agent and the best dose of an anaesthetic usually only display
information regarding (1) times of induction, sedation and recovery; (2) scarce behaviour description; and (3) measurements of hormonal levels (circulating concentrations of catecholamines and cortisol) and immune functions (circulating haemocytes and haemocyte phagocytotic activity). In cephalopods, not only the amount of
anaesthetics tested is high and not fully proven (Sykes et al. 2012) but also the great
majority of these types of studies only include items concerning (1) and, recently,
(2) (e.g. Seol et al. (2007) and Estefanell et al. (2011)). According to Broom (2008),
this is insufficient information to determine the viability of a given anaesthetic.
The development of new tools and the correct application of the existing ones for
the assessment of anaesthetics are of utmost importance to obtain a clear and full
understanding of animal reaction during the evaluation of anaesthesia and euthanasia procedures. There is increasing evidence that alternative methods (Kittilsen
et al. 2009) and available technology may provide simpler and more humane methods of assessing stress responsiveness than invasive methods, such as determination
of plasma cortisol, which is widely used in fish (Ellis et al. 2012). In addition, the
most established methods of assessing primary and secondary stress response in
fish (such as plasma cortisol and glucose (Pottinger 2008)) were never applied to
cephalopods nor do they have a non-humane application (small amount of available
blood and difficult access for extraction will require slaughtering), whether due to
the type and location of the circulatory system of this class (Schipp 1987b) or by
lack of reliability of these methods at given conditions, as suggested by MartínezPorchas et al. (2009). Moreover, according to Ashley (2007), both behavioural and
physiological measures of welfare are necessary for the correct interpretation of
stress responsiveness. While there is a wealth of knowledge on the physiological
consequences of many aquaculture practices in fish, it is now equally important
to understand the behavioural responses to these practices and to relate them to
welfare in cephalopods (Gonçalves et al. 2012). The assessment of welfare during
the application of these agents should be performed using noninvasive and multiple
methods that need to be certified or developed. Furthermore, the study of stress
responsiveness of anaesthesia, analgesia and euthanasia agents should be accomplished through refined animal welfare methodologies (based on the 3 Rs principle)
in cephalopods.
6 Welfare and Diseases Under Culture Conditions
The use of anaesthetics facilitates work at the research level and is required for
invasive studies, where cephalopods must be held immobile for extended periods
of time. Nonetheless, anaesthetics are also used to reduce the level of stress associated with such procedures. In addition, an overdose of anaesthetics is also routinely
used as an effective and humane mean of euthanizing fish, and similar procedures
are already in use for cephalopods. However, the correct assessment of anaesthesia,
analgesia and euthanasia agents is a key aspect to determine the best agents, and the
physiology-based methods used for fish still need to be validated in cephalopods.
It is also important that the study of effective agents should be performed using a
welfare-based approach and this requires the development of new methods to accomplish this mission in the most ethical and humane way as possible. Studies to
determine a given agent and the best dose of an anaesthetic usually only display
information regarding (1) times of induction, sedation and recovery; (2) scarce behaviour description; and (3) measurements of hormonal levels (circulating concentrations of catecholamines and cortisol) and immune functions (circulating haemocytes and haemocyte phagocytotic activity). In cephalopods, not only the amount of
anaesthetics tested is high and not fully proven (Sykes et al. 2012) but also the great
majority of these types of studies only include items concerning (1) and, recently,
(2) (e.g. Seol et al. (2007) and Estefanell et al. (2011)). According to Broom (2008),
this is insufficient information to determine the viability of a given anaesthetic.
The development of new tools and the correct application of the existing ones for
the assessment of anaesthetics are of utmost importance to obtain a clear and full
understanding of animal reaction during the evaluation of anaesthesia and euthanasia procedures. There is increasing evidence that alternative methods (Kittilsen
et al. 2009) and available technology may provide simpler and more humane methods of assessing stress responsiveness than invasive methods, such as determination
of plasma cortisol, which is widely used in fish (Ellis et al. 2012). In addition, the
most established methods of assessing primary and secondary stress response in
fish (such as plasma cortisol and glucose (Pottinger 2008)) were never applied to
cephalopods nor do they have a non-humane application (small amount of available
blood and difficult access for extraction will require slaughtering), whether due to
the type and location of the circulatory system of this class (Schipp 1987b) or by
lack of reliability of these methods at given conditions, as suggested by MartínezPorchas et al. (2009). Moreover, according to Ashley (2007), both behavioural and
physiological measures of welfare are necessary for the correct interpretation of
stress responsiveness. While there is a wealth of knowledge on the physiological
consequences of many aquaculture practices in fish, it is now equally important
to understand the behavioural responses to these practices and to relate them to
welfare in cephalopods (Gonçalves et al. 2012). The assessment of welfare during
the application of these agents should be performed using noninvasive and multiple
methods that need to be certified or developed. Furthermore, the study of stress
responsiveness of anaesthesia, analgesia and euthanasia agents should be accomplished through refined animal welfare methodologies (based on the 3 Rs principle)
in cephalopods.
6 Welfare and Diseases Under Culture Conditions