Effects of different feeding frequencies on growth, cataract development and histopathology of lumpfish (Cyclopterus lumpus L.)

Under embargo until: 2020-11-13Three duplicate groups of individually tagged lumpfish (mean initial weight: 22.3 ± 2.5 g) were fed either daily (7DW); four days per week (4DW) or three days per week (3DW) at a feeding rate of 2% body weight day−1 for a period of 126 days. There were significant differences in growth rates between the groups with the 7DW fish having the highest growth rates. Cataract prevalence was 53% lower in the 3DW group compared to the 7DW group. Histological examination showed that in some individuals in all three groups there was moderate expansion of the lamina propria in the mid and hind gut regions of the intestine with tissue most likely to represent fibrous tissue with scattered leucocytes. The severity of inflammation appeared to increase the more frequent the fish were fed with the 7DW fish having the highest inflammation score in these tissues. Feeding fish daily also resulted in higher levels of liver vacuolisation and chronic inflammation of the lamina propria in the mid and hind gut region of the intestines. Results from the present study show that restricted feeding regimes can be used to control growth and improve gut and eye health in lumpfish.acceptedVersio

Helserisikovurdering av PT73 E. coli (THR) bakteriebiomasse (EFSA/GMO/FR/2007/44) fra Ajinomoto Eurolysine. Uttalelse fra Faggruppe for genmodifiserte organismer og Faggruppe for fôr til terrestriske og akvatiske dyr Vitenskapskomiteen for mattrygghet

publishedVersio

Helserisikovurdering av PT73 (TM) bakteriebiomasse (EFSA/GMO/FR/2008/59) fra Ajinomoto Eurolysine 1. innspillsrunde. Uttalelse fra Faggruppe for genmodifiserte organismer og Faggruppe for fôr til terrestriske og akvatiske dyr Vitenskapskomiteen for mattrygghet

publishedVersio

Helserisikovurdering av PL73 (LM) bakteriebiomasse (EFSA/GMO/FR/2008/61) fra Ajinomoto Eurolysine 1. innspillsrunde. Uttalelse fra Faggruppe for genmodifiserte organismer og Faggruppe for fôr til terrestriske og akvatiske dyr Vitenskapskomiteen for mattrygghet

publishedVersio

The effect of continuous light at low temperatures on growth in Atlantic salmon reared in commercial size sea pens

The aim of this study was to investigate the effect of continuous light of different duration, applied from late autumn to spring in the second year of the production cycle, on the production performance of Atlantic salmon in Northern Norway. The underlying hypothesis is that the introduction of continuous light (LL) superimposed on the natural light before December (the preferred continuous light regime in Northern Norway) could enhance growth and inhibit maturation in the subsequent year. To test this, two large, commercial scale experiments were performed [Experiment 1 in 2014 at 69.47°N, 18.26°E, and Experiment 2 in 2015 at 69.80°N, 19.42°E] where salmon of initial size of 1–1.5 kg were subjected to LL at different time points during the period between 11 November and 13 December, and reared under LL until 31 March the following year. In Experiment 1 the water temperature at 6 m depth ranged between 6.7 °C in November and 3.6 °C in March and in Experiment 2 the water temperature at 6 m depth ranged between 8.3 °C in November and 3.6 °C in March and 6.8 °C in May 2016. Before and after the period with LL, all fish were reared under natural light. Growth was improved by 13–20% in the early exposed groups (15 Nov and 11 Nov) compared to the late exposed groups (13 Dec.). No maturation was seen in the experimental groups at slaughter (Exp. 1: July–September 2015, Exp. 2: May 2016). Vertebra deformities did not differ between the early and late exposed groups suggesting that continuous light promotes growth at lower temperatures, while supporting normal vertebra development. Only minor differences in flesh texture (measured as differences in cathepsin L + B activity) were found in both experiments. It is concluded that a considerable growth benefit may be achieved by exposing Atlantic salmon to continuous light from early November in their first year in seawater, i.e. one month earlier than presently used by the salmon farming industry in Northern Norway

Flesh quality of Atlantic salmon smolts reared at different temperatures and photoperiods

Possible interactive effects of temperature and photoperiod on flesh quality in Atlantic salmon post‐smolts were studied. Juvenile (initial mean weight 96.0 g ± 3.1 SEM ) Atlantic salmon were reared at six different combinations of temperatures (4.3, 6.5 or 9.3°C) and photoperiods (continuous light or simulated natural photoperiod). At termination of the trial, the fish were slaughtered and flesh samples taken to investigate quality and textural properties in the different experimental groups. Final weight in the six experimental groups varied between 174 and 345 g. Softer texture was seen in the fast growing groups. Photoperiod has only minor effect on flesh quality and textural properties, whereas temperature had significant impact on most of the measured variables. Although positive for growth, higher temperatures might be less favourable in relation to softer muscle tissue

Flesh quality of Atlantic salmon smolts reared at different temperatures and photoperiods

Possible interactive effects of temperature and photoperiod on flesh quality in Atlantic salmon post‐smolts were studied. Juvenile (initial mean weight 96.0 g ± 3.1 SEM) Atlantic salmon were reared at six different combinations of temperatures (4.3, 6.5 or 9.3°C) and photoperiods (continuous light or simulated natural photoperiod). At termination of the trial, the fish were slaughtered and flesh samples taken to investigate quality and textural properties in the different experimental groups. Final weight in the six experimental groups varied between 174 and 345 g. Softer texture was seen in the fast growing groups. Photoperiod has only minor effect on flesh quality and textural properties, whereas temperature had significant impact on most of the measured variables. Although positive for growth, higher temperatures might be less favourable in relation to softer muscle tissue

Flesh quality of Atlantic salmon smolts reared at different temperatures and photoperiods

acceptedVersio