Transcriptomic and physiological responses to fishmeal substitution with plant proteins in formulated feed in farmed Atlantic salmon (Salmo salar)

Abstract

BackgroundAquaculture of piscivorous fish is in continual expansion resulting in a global requirement to reduce the dependence on wild caught fish for generation of fishmeal and fish oil. Plant proteins represent a suitable protein alternative to fish meal and are increasingly being used in fish feed. In this study, we examined the transcriptional response of Atlantic salmon (Salmo salar) to a high marine protein (MP) or low fishmeal, higher plant protein replacement diet (PP), formulated to the same nutritional specification within previously determined acceptable maximum levels of individual plant feed materials.ResultsAfter 77 days of feeding the fish in both groups doubled in weight, however neither growth performance, feed efficiency, condition factor nor organ indices were significantly different. Assessment of histopathological changes in the heart, intestine or liver did not reveal any negative effects of the PP diet. Transcriptomic analysis was performed in mid intestine, liver and skeletal muscle, using an Atlantic salmon oligonucleotide microarray (Salar_2, Agilent 4x44K). The dietary comparison revealed large alteration in gene expression in all the tissues studied between fish on the two diets. Gene ontology analysis showed, in the mid intestine of fish fed PP, higher expression of genes involved in enteritis, protein and energy metabolism, mitochondrial activity/kinases and transport, and a lower expression of genes involved in cell proliferation and apoptosis compared to fish fed MP. The liver of fish fed PP showed a lower expression of immune response genes but a higher expression of cell proliferation and apoptosis processes that may lead to cell reorganization in this tissue. The skeletal muscle of fish fed PP vs MP was characterized by a suppression of processes including immune response, energy and protein metabolism, cell proliferation and apoptosis which may reflect a more energy efficient tissue.ConclusionsThe PP diet resulted in significant effects on transcription in all the 3 tissues studied. Despite of these alterations, we demonstrated that high level of plant derived proteins in a salmon diet allowed fish to grow with equal efficiency as those on a high marine protein diet, and with no difference in biometric quality parameters.

Influence of dietary inclusion of a wet processed faba bean protein isolate on post-smolt Atlantic salmon ( Salmo salar )

“…However, the transcriptomic response in pyloric caeca gave no obvious clues the chemical identity of the factor provoking the adverse reaction, which was perhaps not surprising. There are few studies investigating the molecular response of pyloric intestine to reinforce the present data (Morais et al, 2012;Betancor et al, 2015;De Santis et al, 2015c) as most studies on the effects of dietary plant proteins have focussed on distal intestine (Tacchi et al, 2011(Tacchi et al, , 2012Kortner et al, 2012;Sahlmann et al, 2013;De Santis et al, 2015d;Krol et al, 2016). In salmon fed increasing levels of soybean meal that provoked increasing enteritis, digestive enzyme activities in distal intestine were decreased, as observed in the present study (Krogdahl et al, 2003).…”

Effect of fishmeal replacement by poultry by-product meal on growth performance, proximate composition, digestive enzyme activity, haematological parameters and gene expression of gilthead seabream (Sparus aurata )

“…Tacchi et al. () observed inhibition of catD expression in salmon ( S. salar ) fed with plant proteins, while the opposite has been observed in rainbow trout (Alami‐Durante, Médale, Cluzeaud, & Kaushik, ).…”

Dietary arginine supplementation mitigates the soybean meal induced enteropathy in juvenile turbot,Scophthalmus maximusL.

“…Soy protein has become a dominating alternative protein source in aqua‐feed. However, the use of soybean meal in feed for marine carnivorous fish species is still limited due to that high doses of dietary soybean meal could induce negative impacts on fish growth performance and other physiological processes, especially intestinal health (Hu et al., ; Marjara, Chikwati, Valen, Krogdahl & Bakke, ; Tacchi et al., ). Some countermeasures have been administered for the extensive use of soybean meal in farmed fish, including improving processing technologies and breeding soy‐protein‐tolerant varieties.…”