Survival, Growth and RNA/DNA Ratio of Pagrus major Cultured under Three Different Feeding Regimes During Early Development

Abstract

The nutritional status of red sea bream Pagrus major (30-day-old) cultured under three different feeding regimes: 1) rotifer, Artemia and artificial diet (RAA), 2) rotifer and artificial diet (RA) and 3) artificial diet (A) only were evaluated depending on RNA/DNA ratios. The duration of the experiment was four weeks. The final average weight of fish was significantly (P< 0.05) higher in RAA (1555 ± 119 mg) than RA (1010 ± 145 mg) and A (927 ± 170 mg). Specific growth rate was significantly (P< 0.05) higher in RAA (7.376) and RA (5.617) at the end of the first week of culture compared to the other weeks. In artificial diet fed fish, SGR was significantly (P< 0.05) higher at the end of the second week (4.542) compared to the other weeks. The DNA concentration was significantly (P< 0.05) higher at the end of the second week of feeding than in the remaining culture period regardless of feeding conditions. The RNA concentration increased from the first to the second week of culture, followed by a decrease in RNA concentration at the end of the third week and then a re-increase at the end of the fourth week in three treatments. The amount of RNA of fish was significantly (P< 0.05) higher in RAA and RA treatments than in artificial diet fed fish at the end of the second week. The RNA/DNA ratio showed a direct relationship with growth rate in these three different treatments. The RNA/DNA ratio was significantly (P< 0.05) higher in RAA than RA and A showing the superiority of this feeding regime during early development.