Zebrafish, a successful tool for Aquaculture research

Aquaculture is the breeding, rearing, and harvesting of fish, shellfish, algae, and other aquatic organisms. The rapid world population growth and the declining of world fish catches have created the need for additional protein sources for human nutrition. To this regard, the Food and Agriculture Organization of the United Nations and other relevant international Institutions (e.g., EU) have suggested aquaculture as strategic sector. The growth rate of the aquaculture sector is higher than any other food production industry with an estimated rate of 5.3 percent per year in the period 2001–2018. For supporting such as trend, there is a strong need of new research in many areas such as genetic, reproduction, nutrition, and welfare. Thanks to the small size, short generation time interval, prolificity, easy management and manipulation, zebrafish is an excellent tool for aquaculture research. In fact, the genetic similarity between zebrafish and other fish species of interest for the aquaculture sector is greater than that existing between zebrafish and mammals, such as human. Nonetheless, species-specific differences must be still considered. In the past decade, zebrafish proved to be a reliable model for in vivo studies on fish immune response, vaccines development, drugs screening, infectious and inflammatory diseases that are of some concern for the aquaculture industry. Furthermore, research has been carried out on fish nutrition, reproduction and behaviour contributing to improve fish growth performances, survival rate, husbandry procedures, farming stress management, disease resistance, among others. To replace fishmeal and improving aquaculture sustainability, studies on the use of plant (e.g., soybean meal, rapeseed meal, corn gluten meal, etc.) or animal (e.g., krill meal, poultry meal, yeast derived by-product, insect meal, etc.) alternative protein sources, have been also carried out. At the Department of Veterinary Science of the University of Pisa, zebrafish has been used as fish model for studies concerning several aspects. To enhance immunity and fish health, 1,3-1,6 ß-glucan were tested on tissues regeneration (wound healing) and disease resistance (Edwardsiella tarda). Plant extracts known for their antioxidant or sedative properties (e.g., Cannabis sativa, chestnut, Melissa officinalis, etc.) were tested to limit the negative effects of stressful farming conditions (e.g., unbalanced diets, high fish stocking density, fish transportation, etc.). Dipeptides (carnosine and glycyl-proline) were also used to promote fish health and gut function. For improving aquaculture sustainability, bee pollen, Hermetia illucens meal, and yeast derived by-product, were used as feed ingredient for partially replacing fish feed or fishmeal in fish diet. Besides that, gingerol and 1,3-1,6 ß-glucan have been tested as possible food aid for patients affected by Muscular Dystrophy. Considering that aquaculture is a relatively recent practice, there is still a relevant need of research for enhancing fish performances and health, and to cope with stress related to the farming practices (e.g., fish transportation and selections). In this context, zebrafish already represent a successful key tool for aquaculture research.