Daily rhythms of swimming activity, synchronization to different feeding times and effects on anesthesia practice in an Amazon fish species (Colossoma macropomum)

ABSTRACT

This study aimed to investigate the existence of day-night differences in the time for anesthesia and recovery in tambaqui exposed to the anesthetic eugenol and the influence of feeding time. Thus, we evaluated: (1) swimming activity; (2) food anticipatory activity (FAA) as a synchronizer of swimming activity and change to susceptibility to anesthetic; and (3) the effects of diurnal/nocturnal anesthesia exposure of fish feeding in the mid-light phase: 12:00 h (ML) and fish feeding in the mid-dark phase: 00:00 h (MD). Our findings revealed strictly nocturnal activity for tambaqui (94.2%), known as diurnal fish to date. Moreover, FAA was observed in tambaqui fed at MD, which showed a sustained increase in activity that began 2 h before feeding time and lasted until feeding. In contrast, no FAA was observed in fish fed at ML. Regarding anesthesia by day or night, the tambaqui treated with eugenol exhibited no difference in induction time. However, differences were observed in recovery times, with fish anesthetized at day recovering in 1–2 min and fish anesthetized at night recovering in 5–7 min. In short, our findings revealed for the first time the nocturnal behavior of tambaqui. These results indicated that recovery by day/night by eugenol in tambaqui has a strong dependence of behavioral patterns and the time of day.

KEYWORDS:

• Biological rhythms
• daily anesthetic susceptibility
• freshwater fish
• rhythmicity

Acknowledgements

The authors thank Bahia Pesca for supplying juvenile tambaqui.

Additional information

Funding

This work was supported by the grant in aid from the Programa Nacional de Desenvolvimento Científico e Tecnológico, projeto Universal/CNPq, Special Visiting Researcher Project-PVE, CNPq (401416/413 2014-3) to R. Fortes-Silva and F.J. Sánchez-Vázquez. Also, R. Fortes-Silva was funded through a research fellowship from CNPq/Brazil (Produtividade em Pesquisa-PQ) and JFLO was funded through a “Ramón y Cajal” research fellowship granted by the Spanish Ministry of Economy and Competitiveness (RYC-2016-20959);Conselho Nacional de Desenvolvimento Científico e Tecnológico [305734/2016-4,401416/ 413 2014-3]