EFFECTS OF DIFFERENT STARVATION CYCLES ON COMPENSATORY GROWTH AND BODY COMPOSITION OF RAINBOW TROUT REARED IN CAGES

Compensatory or catch-up growth is used to determine the increases of growth rates and effective feed utilization in fish. Compensation of growth can be observed as three different types; over, full and partial compensation. The responses of fish to compensatory growth are closely related to many factors such as how long starvation prior to re-feeding cycle takes, whether starvation periods are single cycle or multiple cycles, the size of fish, feed composition, research conditions. In this study aimed to determination of growth performance, feed utilization and proximate composition of rainbow trout fed with high protein and lipid diets by using different starvation cycles in cage conditions.

This study was conducted under cage culture conditions in Seyhan Dam Lake, Adana, Turkey. Study was designed as follows: the control (C) group (continuous feeding), G1 (1day starvation+9 days re-feeding), G2 (2 days starvation+ 8 days re-feeding) and G3 (3 days starvation+7days re-feeding). The one hundred rainbow trouts were randomly stocked into each cage (1.7×1.7×1.7 m size) as three replicates. The fish were fed twice a day with fish meal based diet contained 50% crude protein and 22% crude lipid during 80 days.

The highest final weight was observed in C group (Table 1). G1 group had the best partial compensation among starvation groups. The best FCR was found in G3. In addition to this, G3 group fish were used effectively diet protein and lipid according the other groups. The proximate composition was effected by the feeding regimes (Table 2). But it was not an adverse effect when comparing the initial composition. In conclusion, it was determined that trouts deprived of feed for a short time exhibited partial compensation in growth fed with high lipid and high protein diet. Also, they were not adversely affected in terms of feed utilization and nutritional composition.