Premium
The effect of vaccination, ploidy and smolt production regime on pathological melanin depositions in muscle tissue of A tlantic salmon, S almo salar L
Author(s) -
Larsen H A S,
Austbø L,
Nødtvedt A,
Fraser T W K,
Rimstad E,
Fjelldal P G,
Hansen T,
Koppang E O
Publication year - 2014
Publication title -
journal of fish diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 85
eISSN - 1365-2761
pISSN - 0140-7775
DOI - 10.1111/jfd.12106
Subject(s) - melanin , ploidy , biology , smoltification , vaccination , immune system , salmo , gene , zoology , andrology , immunology , fish <actinopterygii> , fishery , genetics , salmonidae , medicine
Abstract The presence of melanin in muscle fillets of farmed salmon represents a considerable quality problem for the salmon industry with major economic concerns. In this study, we have examined the presence of abnormal pigmentation in vaccinated versus unvaccinated Atlantic salmon, S almo salar L ., and evaluated possible differences between diploid and triploid fish. Furthermore, the impact of the smolt production regime at ambient (4.5 °C) versus elevated temperature (16 °C) was investigated. Pigmented muscle spots were analysed for the expression of genes involved in melanization (tyrosinase gene family) and immune‐related response in addition to morphological investigations. The proportion of fish with intramuscular melanin deposits was not significantly different between vaccinated and unvaccinated fish, regardless of ploidy. However, an interaction between vaccination and smolt regime was shown, where smoltification at elevated temperature after vaccination increased the number of affected individuals compared with vaccination followed by simulated natural smoltification. Furthermore, there were overall more fish with melanin spots amongst the triploids compared with their diploid counterparts. Transcription of the tyrosinase gene family confirmed an onsite melanogenesis in all pigment spots. The histological examination and the expression of the immune‐related genes revealed a chronic polyphasic myopathy that was not affected by vaccination, ploidy or smolt production regime.