International survey on the use and welfare of zebrafish Danio rerio in research.

A survey was conducted regarding zebrafish Danio rerio use for scientific research with a focus on: anaesthesia and euthanasia; housing and husbandry; breeding and production; refinement opportunities. A total of 98 survey responses were received from laboratories in 22 countries in Europe, North America, South America, Asia and Australia. There appears a clear and urgent need to identify the most humane methods of anaesthesia and euthanasia. Aversive responses to MS-222 were widely observed raising concerns about the use of this anaesthetic for D. rerio. The use of anaesthesia in fin clipping for genetic identification is widely practised and there appears to be an opportunity to further develop less invasive methods and refine this process. Optimization (and potentially standardization) of feeding is an area for further investigation. Given that diet and body condition can have such profound effects on results of experiments, differences in practice could have significant scientific implications. Further research into transition between dark and light phases in the laboratory appears to represent an opportunity to establish best practice. Plants and gravel were not considered practical by many laboratories. The true value and benefits need to be established and communicated. Overproduction is a concern both from ethical and financial viewpoints. There is an opportunity to further reduce wastage of D. rerio. There are clear concerns and opportunities for the scientific community to work together to further improve the welfare of these important laboratory models.

Key issues concerning environmental enrichment for laboratory-held fish species.

An improved knowledge and understanding of the fundamental biological requirements is needed for many of the species of fish held in captivity and, without this knowledge it is difficult to determine the optimal conditions for laboratory culture. The aim of this paper is to review the key issues concerning environmental enrichment for laboratory-held fish species and identify where improvements are required. It provides background information on environmental enrichment, describes enrichment techniques currently used in aquatic ecotoxicology studies, identifies potential restrictions in their use and discusses why more detailed and species-specific guidance is needed.

Meeting energy budgets by modulation of behaviour and physiology in the eel (Anguilla anguilla L.).

Availability of energy for feeding, and the scope to accommodate the associated increase in oxygen demand (SDA: specific dynamic action) can, to a large degree, regulate the future feeding and energy availability of an animal. There is a fundamental conflict between locomotion and SDA within the physiological capacity of a mobile organism to respire sufficiently in order to simultaneously meet both requirements. This paper is a first attempt to integrate the costs of behaviour and physiology and produce a testable model of energy allocation in the eel. Total oxygen consumption (metabolic rate MO2) of the eel (Anguilla anguilla L.) was 109 micromol O2 x g(-1) x day(-1) with a cost of measured protein synthesis representing 49% of this value, and measured routine swimming (locomotor) activity representing approximately 34%. By allocating periods of reduced activity, the eel is able to develop a strategy to prudently meet the costs of feeding and temporally balance energy budgets (in terms of oxygen) by modulation of the behaviour and demands of physiology.