Reduced sexual maturation in male post-smolt 1+ Atlantic salmon (Salmo salarL.) by dietary tetradecylthioacetic acid

Abstract

In the present study, the possible e¡ect of dietary treatment on early sexual maturation in post-smolt Atlantic salmon, without any negative e¡ect regarding growth, was investigated. The experiment was performed using 4400 individually marked (Pit tag) 11 salmon, fed either a control diet or a diet supplemented with 0.5% tetradecylthioacetic acid (TTA) in duplicates for 3,6 or 12 weeks after sea transfer. Compared with the control, dietary supplementation of TTA resulted in a threefold reduction in incidence of sexual mature males (0.6% vs. 1.8%). A curve-linear relationship between relative reduction in maturation and weeks of feeding TTA was found, indicating that the e¡ect is most marked as a result of the ¢rst weeks of feeding and then levelling o¡. No negative dietary impact on growth was observed. As the level of fat in the muscle was reduced by dietary TTA, it seems that post-smolt supplemented dietary TTA do not accumulate high enough energy stores to start the maturation process, whereas the energy-enhancing e¡ect of TTA due to increased fatty acid oxidation capacity may maintain the growth potential. Compared with immature salmon, sexually maturing ¢sh revealed increased spring growth before the onset of maturation.

Reduced growth, condition factor and body energy levels in Atlantic salmon Salmo salar L. during their first spring in the sea

“…The mean body weight at sea transfer was 104±0 g, and the mean weight in September was of 438±4 g. The fish were fed a commercial diet produced at the Biomar Technology Centre (Brande, Denmark). For additional information about the experimental set‐up and diets (see Rørvik et al . 2007; Alne, Thomassen et al .…”

“…Condition factor (CF), level of muscle fat and body energy content all decrease following S1 smolt transfer to the sea in the spring (Måsøval, Åsgård, Wathne, Shearer, Staurnes & Sigholt 1994; Bendiksen, Arnesen & Jobling 2003; Lysfjord, Jobling & Solberg 2004; Alne, Thomassen, Sigholt, Berge & Rørvik 2009). Furthermore, the S1 smolt may eat little and grow slowly (Usher, Talbot & Eddy 1991; Toften, Arnesen & Jobling 2003; Lysfjord et al .…”

A Review of Factors Influencing Maturation of Atlantic Salmon, Salmo salar, with Focus on Water Recirculation Aquaculture System Environments

“…The emerging salmon RAS industry could benefit from diets that are designed specifically for the rapid growth and high metabolism that is expected within these culture systems. Finally, baseline studies focusing on a range of nutrients in salmon diets, and their association with early maturation, still need to be carried out, such as work by Alne et al () who found reduced sexual maturation in male postsmolts fed supplemental tetradecylthioacetic acid.…”

Reduction of early sexual maturation in male S0 Atlantic salmon (Salmo salarL.) by dietary supplementation of tetradecylthioacetic acid (TTA)

“…) or in the autumn after two or more sea winters (Duston & Saunders ). The process of initiation of sexual maturation of fish seems to depend on different stimuli gained from both internal factors like age and state of energy reserves (Thorpe, Talbot, Miles & Keay ; Shearer & Swanson ; Alne, Thomassen, Sigholt, Berge & Rørvik ; Taranger et al . ) and external factors like photoperiod and abundance of feed (Thorpe et al .…”