Abstract

Haematological parameters are often used as health status and stress indicators in fish. However, information on the effects of artificial photoperiods on these parameters is scarce and ambiguous. The consequences of three different artificial photoperiod regimes [light/day 12 h:12 h (LD 12:12) for 150 days as controls; LD 14:10 and LD 24:0, both for an initial 60 days, and then LD 12:12 for the remaining 90 days] were evaluated in trout. In all fish the haemogram and the erythrocyte production index (EPI) were assessed at days 7, 14, 30 and 60 (phase 1) and at days 90, 120 and 150 (phase 2). At the end of phase 1, photoperiods LD 14:10 and 24:0 induced higher production of immature (late basophilic) erythrocytes (0.06–0.08 × 1012 cells/l, P < 0.05) and elevated EPI (young erythrocytes = 1.6 in LD 14:10, 2.25 in LD 24:0; late basophilic erythrocytes = 4.1–4.9 in LD 14:10, 3.3 in LD 24:0) than in controls (late basophilic erythrocytes = 0.02–0.04 × 1012 cells/l; EPI young erythrocytes = 0.2–1.0; EPI late basophilic erythrocytes = 1.4–2.7). During phase 2, only reduced numbers of lymphocytes and thrombocytes were observed at day 150 in the LD 14:00 group. An increase in the EPI (1.9) of control young erythrocytes was found at day 150.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.