RT journal article
T1 Dietary Tryptophan Induces Opposite Health-Related Responses in the Senegalese Sole (Solea senegalensis) Reared at Low or High Stocking Densities With Implications in Disease Resistance
A1 Azeredo, Rita
A1 Machado, Marina
A1 Martos Sitcha, Juan Antonio
A1 Martínez-Rodríguez, Gonzalo
A1 Moura, Joana
A1 Peres, Helena
A1 Oliva-Teles, Aires
A1 Afonso, António
A1 Mancera Romero, Juan Miguel
A1 Costas, Benjamín
A2 Biología
K1 amino acid
K1 neuro-endocrine response
K1 functional feed
K1 cortisol
K1 crowding stress
AB High rearing densities are typical conditions of both inland and onshore intensiveaquaculture units. Despite obvious drawbacks, this strategy is nonetheless used toincrease production profits. Such conditions inflict stress on fish, reducing their ability tocope with disease, bringing producers to adopt therapeutic strategies. In an attempt toovercome deleterious effects of chronic stress, Senegalese sole, Solea senegalensis,held at low (LD) or high density (HD) were fed tryptophan-supplemented diets withfinal tryptophan content at two (TRP2) or four times (TRP4) the requirement level, aswell as a control and non-supplemented diet (CTRL) for 38 days. Fish were sampledat the end of the feeding trial for evaluation of their immune status, and mortalitieswere recorded following intra-peritoneal infection with Photobacterium damselae subsp.piscicida. Blood was collected for analysis of the hematological profile and innateimmune parameters in plasma. Pituitary and hypothalamus were sampled for theassessment of neuro-endocrine-related gene expression. During the feeding trial, fishfed TRP4 and held at LD conditions presented higher mortalities, whereas fish keptat HD seemed to benefit from this dietary treatment, as disease resistance increasedover that of CTRL-fed fish. In accordance, cortisol level tended to be higher in fish fedboth supplemented diets at LD compared to fish fed CTRL, but was lower in fish fedTRP4 than in those fed TRP2 under HD condition. Together with lower mRNA levels ofproopiomelanocortin observed with both supplementation levels, these results suggestthat higher levels of tryptophan might counteract stress-induced cortisol production,thereby rendering fish better prepared to cope with disease. Data regarding sole immunestatus showed no clear effects of tryptophan on leucocyte numbers, but TRP4-fedfish displayed inhibited alternative complement activity (ACH50) when held at LD, asopposed to their HD counterparts whose ACH50 was higher than that of CTRLfedfish. In conclusion, while dietary tryptophan supplementation might have harmfuleffects in control fish, it might prove to be a promising strategy to overcome chronicstress-induced disease susceptibility in farmed Senegalese sole.
PB FRONTIERS MEDIA SA
SN 1664-042X
YR 2019
FD 2019-05
LK http://hdl.handle.net/10498/21306
UL http://hdl.handle.net/10498/21306
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 22-sep-2026