Transcriptional stress responses to environmental and husbandry stressors in aquaculture species

Abstract

Stress of aquatic animals occurs due to physical and physiological disturbances in the aquatic environment or system when transportation, crowding, handling or changes of physical and chemical factors take place. There are three regulatory systems having a vital role in stress response: the neural, endocrine and immune systems. Fish exhibit multiple genomic and physiological responses to adjust the compensatory or adaptive mechanism that allows them to mitigate the stressors, maintain their haemostasis and survive. In this review, we describe multiple important genes that are associated with responses to environmental and husbandry stressors and that could be used as biomarkers of environmental and husbandry stressors in fish. The described environmental and husbandry stressors include salinity, temperature, hypoxia and hyperoxia, confinement, density and handling. The main role of stress response in aquatic animals is to compensate or adapt their biological systems and arrange the metabolism to afford the energy required by the stressor and a wide array of metabolic processes and pathways are involved. We summarized and discussed highly significant genes in several organs and tissues that are involved and active during this adaption process. The traditional stress biomarkers in some circumstances have some difficulties in interpretation of results and lead to tricky diagnosis and searching and understanding alternative tools is critical for aquaculture, fisheries and fish welfare. Using genomic tools to study the candidate genes associated with stress responses are often unique signatures or imprints of specific stressors and could determine early signs of stressors.

The Transcriptomic Responses of Atlantic Salmon (Salmo salar) to High Temperature Stress Alone, and in Combination with Moderate Hypoxia

“…Transcriptomic techniques allow for the high-throughput identi cation of genes that are sensitive to particular conditions, and can be used as biomarkers for the detection and quanti cation of stress levels and stress tolerance. In this context, the development of diagnostic biomarkers for quantifying the impact of environmental stressors on an organism's physiology and health has received increased attention by the aquaculture industry and for use in ecological surveys [89,92,151]. Our results agree with recent studies which show that the genes serpinh1, hsp90aa1 and cirbp are reliable molecular biomarkers for the detection and quanti cation of thermal stress in salmonids [89,92,152].…”

Thermal tolerance of paralarvae of Patagonian red octopusEnteroctopus megalocyathus

“…In general, the trends observed in the paralarvae of Patagonian red octopus were similar to most studies reporting that CTMin and CTMax increase along with the acclimation temperature (Dülger et al., ; Noyola et al., ). Also, it was possible to observe that the type of embryo incubation affected critical temperatures by interacting with the acclimation temperature, reinforcing that critical temperatures are integral responses of the metabolism of organisms, as those involved in growth, immune functions and reproduction (Angilletta et al., ; Díaz et al., , ; Eissa & Wang, ). In paralarvae from maternal care and starved, the highest thermal preference (23.7 ± 3.4°C) was observed at 18°C, stuck to the higher CTMax (27.3°C), without observing a transition zone.…”

“…Considering the manipulation of the eggs in the incubators, it is possible to hypothesize that embryos from maternal care keep a more stable environment than in the incubators. The zootechnical practices involved in cleaning the eggs (one by one) throughout 5 months for embryonic incubation of E. megalocyathus , need to be improved because handling is one of the greatest stressors of parenting aquaculture (Eissa & Wang, ).…”

Comparative molecular analyses of select pH- and osmoregulatory genes in three freshwater crayfishCherax quadricarinatus,C. destructorandC. cainii

“…Gene ontology (GO) terms were assigned to annotated transcripts using Blast2Go Pro (Version 3.0; Conesa et al, 2005 ). Candidate genes were identified based on literature searches, PFAM domains, and GO terms ( Henry et al, 2012 ; Eissa & Wang, 2014 ; Ali et al, 2015b ).…”