INTERACTIVE EFFECTS OF FISH MEAL REPLACEMENT BY PLANT PROTEIN SOURCES AND NOVEL IMMUNOSTIMULATING NUTRIENTS ON INNATE IMMUNE MECHANISMS AND DISEASE RESISTANCE IN FISH: TOWARDS FUNCTIONAL AND SUSTAINABLE FEEDS

Funder

Organizational Unit

Publications

European Sea Bass (Dicentrarchus labrax) immune status and disease resistance are impaired by arginine dietary supplementation

Publication . Azeredo, Rita; Perez-Sanchez, Jaume; Sitja-Bobadilla, Ariadna; Fouz, Belen; Tort, Lluis; Aragao, Claudia; Oliva-Teles, Aires; Costas, Benjamin

Infectious diseases and fish feeds management are probably the major expenses in the aquaculture business. Hence, it is a priority to define sustainable strategies which simultaneously avoid therapeutic procedures and reinforce fish immunity. Currently, one preferred approach is the use of immunostimulants which can be supplemented to the fish diets. Arginine is a versatile amino acid with important mechanisms closely related to the immune response. Aiming at finding out how arginine affects the innate immune status or improve disease resistance of European seabass (Dicentrarchus labrax) against vibriosis, fish were fed two arginine-supplemented diets (1% and 2% arginine supplementation). A third diet meeting arginine requirement level for seabass served as control diet. Following 15 or 29 days of feeding, fish were sampled for blood, spleen and gut to assess cell-mediated immune parameters and immune-related gene expression. At the same time, fish from each dietary group were challenged against Vibrio anguillarum and survival was monitored. Cell-mediated immune parameters such as the extracellular superoxide and nitric oxide decreased in fish fed arginine-supplemented diets. Interleukins and immune-cell marker transcripts were down-regulated by the highest supplementation level. Disease resistance data were in accordance with a generally depressed immune status, with increased susceptibility to vibriosis in fish fed arginine supplemented diets. Altogether, these results suggest a general inhibitory effect of arginine on the immune defences and disease resistance of European seabass. Still, further research will certainly clarify arginine immunomodulation pathways thereby allowing the validation of its potential as a prophylactic strategy.

2015-10Journal article

Open access

New developments and biological insights into the farming of Solea senegalensis reinforcing its aquaculture potential

Publication . Morais, Sofia; Aragão, C.; Cabrita, Elsa; Conceição, L. E. C.; Constenla, Maria; Costas, Benjamín; Dias, Jorge; Duncan, Neil; Engrola, S.; Estevez, Alicia; Gisbert, Enric; Mañanós, Evaristo; Valente, Luísa M. P.; Yúfera, M.; Dinis, Maria Teresa

Senegalese sole was one of the earliest identified candidate species with high potential for aquaculture diversification in the south of Europe. Its culture has been possible, and commercially attempted, for several decades, but intensive production has been slow to take off. This has been explained mostly by serious disease problems, high mortality at weaning, variable growth and poor juvenile quality. However, a strong and sustained research investment that started in the eighties has led to a better understanding of the requirements and particularities of this species. More recently, better management and technical improvements have been introduced, which have led to important progress in productivity and given a new impetus to the cultivation of Senegalese sole. As a result, the last 5 years have marked a probable turning point in the culture of sole towards the development of a knowledge-driven, competitive and sustainable industry. This review will focus on the main technical improvements and advances in the state of knowledge that have been made in the last decade in areas as diverse as reproductive biology, behaviour, physiology, nutritional requirements, modulation of the immune system in response to environmental parameters and stress, and characterization and mitigation of the main disease threats. It is now clear that Senegalese sole has important particularities that differentiate it from other current and candidate marine aquaculture species, which bring about important challenges, some still unsolved, but also notable opportunities (e.g. a nutritional physiology that is better adapted to dietary vegetable ingredients), as will be discussed here.

2016-09Journal article

Restricted access

Can we predict personality in fish? searching for consistency over time and across contexts

Publication . Castanheira, Maria Filipa; Herrera, Marcelino; Costas, Benjamin; Conceicao, Luis E. C.; Martins, Catarina I. M.

The interest in animal personality, broadly defined as consistency of individual behavioural traits over time and across contexts, has increased dramatically over the last years. Individual differences in behaviour are no longer recognised as noise around a mean but rather as adaptive variation and thus, essentially, raw material for evolution. Animal personality has been considered evolutionary conserved and has been shown to be present in all vertebrates including fish. Despite the importance of evolutionary and comparative aspects in this field, few studies have actually documented consistency across situations in fish. In addition, most studies are done with individually housed fish which may pose additional challenges when interpreting data from social species. Here, we investigate, for the first time in fish, whether individual differences in behavioural responses to a variety of challenges are consistent over time and across contexts using both individual and grouped-based tests. Twenty-four juveniles of Gilthead seabream Sparus aurata were subjected to three individual-based tests: feed intake recovery in a novel environment, novel object and restraining and to two group-based tests: risk-taking and hypoxia. Each test was repeated twice to assess consistency of behavioural responses over time. Risk taking and escape behaviours during restraining were shown to be significantly consistent over time. In addition, consistency across contexts was also observed: individuals that took longer to recover feed intake after transfer into a novel environment exhibited higher escape attempts during a restraining test and escaped faster from hypoxia conditions. These results highlight the possibility to predict behaviour in groups from individual personality traits.

2013-04Journal article

Open access