Adult triploid Atlantic salmon (Salmo salar) have higher dietary histidine requirements to prevent cataract development in seawater

Abstract

The study investigated cataract preventive effects of dietary histidine (His) supplementation in triploid Atlantic salmon during seawater grow-out. Groups of individually PIT tagged diploid (2N) and triploid (3N) postsmolts were fed one of two supplemented dietary histidine levels; low (L, 12.6 g kg-1 diet) or high (H, 17.4 g kg-1 diet) from March to September following their first sea winter. Low severity cataracts were detected in both ploidy prior to supplemented His diet application. Thereafter, 3N-L showed progression of cataract development in the second spring-summer period, while development was inhibited in 3N-H. Severity of cataract showed a strong family effect. A positive correlation between initial triploid seawater growth (weight and TGC) under increasing water temperature and cataract severity was identified as a major risk factor. The relationship was reversed at harvest, where triploids were on average 7.5% smaller than their diploid siblings. Lens N-acetyl-histidine content reflected dietary His inclusion level and cataract severity, although no significant differences in lens His content were evident between ploidy or dietary groups. Results indicate that triploid Atlantic salmon appear to have a higher dietary histidine requirement than diploids and that preventative measures can be taken to mitigate further cataract development

Gut morphology of diploid and triploid Atlantic salmon (Salmo salar L.)

“…For example, triploid salmon may require more dietary phosphorus than diploids (Burke et al 2010), and require dietary supplements of histidine to reduce the incidence of ocular cataracts (Taylor et al 2014). In addition, diploid and triploid Atlantic salmon may differ in gut microbiota, with potential consequences for culture performance and health (Cantas et al 2011).…”

“…Although the reasons for this are not clear, differences in egg quality (Taylor et al 2011) and nutritional requirements (Burke et al 2010;Taylor et al 2014) might be key factors.…”

Effectiveness of triploidy as a management tool for reproductive containment of farmed fish: Atlantic salmon (Salmo salar) as a case study

“…; Taylor et al . , ). The underlying causes for these abnormalities are currently unknown, but they likely arise from one or more genotypic, environmental or nutritional effects that are exacerbated by triploidy due to altered gene dosage/expression or increased cell size.…”

“…In an experiment specifically designed to determine the cause of higher cataract incidence in triploid Atlantic salmon, Taylor et al . () formulated two test diets that varied in histidine content, knowing that dietary supplementation of this amino acid reduces the incidence and severity of cataracts in diploid Atlantic salmon. This study clearly showed triploids to have a higher dietary histidine requirement than diploids for reducing the severity of cataracts once they have developed in postsmolts.…”

Genetic screening of farmed Atlantic salmon escapees demonstrates that triploid fish display reduced migration to freshwater

“…However, recent developments in production techniques have solved some of the early challenges experienced with commercial production of triploids (Fjelldal and Hansen 2010;Fraser et al 2012;Frenzl et al 2014;Leclercq et al 2011;Taylor et al 2015). In Norway, which is the worlds largest Atlantic salmon producing country, recent government licensing schemes have encouraged companies to initiate triploid production at a commercial level.…”