Effect of feeding restrictions on development of juvenile cobias, Rachycentron canadum

Abstract

Aim of study: A 45-day trial was conducted to evaluate fasting as a possible way of food strategy during production of juvenile cobias (Rachycentron canadum). Area of study: The study was conducted in the State of Espírito Santo, Brazil. Material and methods: The following different protocols were used to organize their feeding: C, fish fed to satiety twice a day for 45 days; U1, fish fed to satiety twice a day on alternate days; U2, fish fed to satiety twice daily for five consecutive days, followed by two days of food deprivation, cyclically; U5, fish subjected to food deprivation for five days and then fed to satiety twice a day for 40 days; U10, fish subjected to food deprivation for ten days and then fed to satiety twice a day for 35 days; and U15, fish subjected to food deprivation for fifteen days and then fed to satiety twice a day for 30 days. Main results: No mortality was observed during the trial period. The different feeding protocols significantly affected juvenile cobias development and wellbeing. The final weight (g) of cobia juveniles was C – 91.9 ± 9.1; U1 – 75.0 ± 11.2; U2 – 72.2 ± 6.0; U5 – 70.3 ± 6.1; U10 – 63.4 ± 4.6; U15 – 54.4 ± 4.7. No compensatory growth was observed during the entire experimental period. Research highlights: Continuous fasting had a more severe effect than intermittent fasting. Significantly greater hepatocyte counts were correlated with longer fasting periods. Fasting protocols should not be recommended for juvenile cobias.