Effects of photoperiod and feeding interval on food intake and growth rate of Nile tilapia Oreochromis niloticus L.

Abstract

The effects of photoperiod (PPD) and feeding interval on food intake and growth of Nile tilapia Oreochromis niloticus were investigated. In the first two trials, fish were subjected to PPD of 3L : 3D (3LD), 6L : 6D (6LD), 12L : 12D (12LD) and 24L : 24D (24LD) for 6 weeks at 28°C. In Trial 1, the fish (mean weight 3.45 g) were fed 5% of body weight per day and in Trial 2 fish (mean weight 3.60 g) were fed to visual satiation (four meals per day) according to the feeding interval specified for different treatments. In a third trial, fish subjected to 12LD were fed 6% of body weight per day and fish were given 12% every other day under 24LD. Fish exposed to a 6LD PPD had a significantly higher growth rate than those exposed to other PPD in Trials 1 and 2 (P < 0.05). When the fish were fed to satiation, significantly higher food consumption and feed efficiency (P < 0.05), and lower adiposity (P < 0.05) were observed in fish exposed to 6LD PPD than those exposed to 12LD PPD. These results indicated that a 6LD PPD regimen resulted in an improvement of fish growth through stimulated food intake. Thus, these experiments suggested that the growth of Nile tilapia could be controlled by the manipulation of PPD and feeding interval.