Lazado, Carlo C.; Gesto, Manuel; Madsen, Lone and Jokumsen, Alfred (2017) Interplay between daily rhythmic serum-mediated bacterial killing activity and immune defence factors in rainbow trout (Oncorhynchus mykiss). [Samspil mellem daglig rytmisk serum-formidlet bakteriel dræber aktivitet og immun forsvars faktorer hos regnbueørred (Oncorhynchus mykiss).] Fish and Shellfish Immunology, 72, pp. 418-425.
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Summary
Circadian rhythm is emerging as an important regulator of immune functions. However, there is a paucity of information on the influence of this biological phenomenon in the antimicrobial factors in teleost fish. This study investigated the dynamics and interplay of serum-mediated bacterial killing activity and immune defence factors throughout the light:dark (LD) cycle in rainbow trout (Oncorhynchus mykiss). The juvenile fish came from two different emergence time fractions (i.e., late and early) that were believed to exhibit behavioural and physiological differences. Serum collected during the day from fish (mean ± SD: 39.8 ± 6.3 g) reared under 14L:10D photoperiod demonstrated bactericidal activity against Flavobacterium psychrophilum, Yersinia ruckeri and Aeromonas salmonicida subsp. salmonicida of varying magnitude, but no significant differences between the emergence fractions were observed. A day-night comparison in the same batch of fish revealed time-of-day dependence in the bactericidal activity against F. psychrophilum and Y. ruckeri amongst emergence fractions. A group of fish (63.3 ± 4.7 g) from each fraction was entrained to 12L:12D photoperiod for 21 days to investigate whether serum bactericidal activity exhibited daily rhythm. Serum-mediated bacterial killing activity against F. psychrophilum and Y. ruckeri displayed significant daily rhythm in both emergence fractions, where the peak of activity was identified during the light phase. Moreover, several serum defence factors manifested variations during the LD cycle, where anti-protease (ANTI) and myeloperoxidase (MPO) activities exhibited significant daily oscillation. However, there were no remarkable differences in the daily changes of serum factors amongst emergence fractions. Acrophase analysis revealed that the peaks of activity of alkaline phosphatase (only in late fraction), ANTI, lysozyme (only in early fraction) and MPO were identified during the light phase and corresponded with the period when serum-mediated bacterial killing activity was also at its highest. The daily dynamics of bactericidal activity and immune defence factors displayed positive correlation, particularly between MPO and, the two pathogens (i.e., F. pyschrophilum and Y. ruckeri). Taken together, the study revealed that serum-mediated bacterial killing activity and immune defence factors remarkably varied during the LD cycle in rainbow trout. In addition, the two emergence fractions displayed nearly comparable immunological profiles.
Summary translation
Døgnrytmer er ved at vise sig som en vigtig faktor ireguleringen af immun funktioner. Der mangler imidlertid viden om betydningen af dette biologiske fænomen i de antimikrobielle faktorer hos benfisk. Dette studie undersøgte dynamik og samspil af serum-formidlet bakteriel dræber aktivitet og immun forsvars faktorer under hele lys:mørke (LD) cyclus hos regnbueørred (Oncorhynchus mykiss). De juvenile (ca. 40 g/stk) fisk stammede fra to forskellige swim-up fraktioner (dvs. sen og tidlig), som formodedes at udvise forskelle i adfærd og fysiologi. Analyser af serum prøver fra fisk holdt under 14L:10D lys periode viste baktericid aktivitet mod Flavobacterium psychrophilum, Yersinia ruckeri og Aeromonas salmonicida subsp. salmonicida i varierende grad, men der blev ikke observeret signifikante forskelle mellem swim-up fraktionerne. En dag-nat sammenligning i den same batch af fisk afslørede tidspunkt på døgnet afhængighed i den bactericide aktivitet mod F. psychrophilum og Y. ruckeri blndt swim-up fraktioner. A gruppe fisk fra hver fraktion blev udsat for 12L:12D lysperiode i 21 dage for at undersøge evt. dagsrytme i serum bactericid aktivitet. Serum-formidlet bakteriel dræber aktivitet mod F. psychrophilum og Y. ruckeri viste signifikant dagsrytme i begge swim-up fraktioner, hvor peak aktiviteten blev identificeret under lys perioden. Samlet set viste studiet, at serum-formidlet bakteriel dræber aktivitet og immun forsvars faktorer varierede betydeligt under LD cyclus i regnbueørred. Yderligere viste de to swim-up fraktioner nært sammenlignelige immunologiske profiler. .
| EPrint Type: | Journal paper |
|---|---|
| Keywords: | Aquaculture Circadian rhythm Immunity Fish Stress-coping style |
| Subjects: | Animal husbandry > Health and welfare Knowledge management > Research methodology and philosophy |
| Research affiliation: | Denmark > Organic RDD 2 > RobustFish |
| Deposited By: | Jokumsen, Senior Advisory Scientist Alfred |
| ID Code: | 32861 |
| Deposited On: | 05 Apr 2018 11:10 |
| Last Modified: | 05 Apr 2018 11:10 |
| Document Language: | English |
| Status: | Published |
| Refereed: | Peer-reviewed and accepted |
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