Abstract
Nile tilapia (Oreochromis niloticus) belongs to the freshwater fish species with the highest rate of increase of culture production worldwide. Different plant derived saponin extracts were tested for their effect on growth and expression of growth hormone (GH) and insulin-like growth factor-1 (IGF-1) genes in O. niloticus. Saponin fractions were eluated from fenugreek (F, Trigonella foenum-graecum) in consecutive methanol concentrations (40, 60 and 80%) and from soap bark tree (Q, Quillaja saponaria, 80% methanol) and added to the diets at a concentration of 150 ppm.
Fish were kept in the chambers of a respirometric system and in parallel in aquaria of a recirculation system and fed for eight weeks. Every two weeks one animal per group from the aquaria was slaughtered to determine the hormone levels as well as the gene expression profile using semi quantitative Real Time-PCR (RT-PCR). The fish in the respirometric system were slaughtered at the end of the eight weeks to determine the feed conversion ratio and whole body chemical composition. In a previous experiment with the same treatments, saponin supplementation in the diet affected expression of IGF-1 and GH in C. carpio. The growth of the experimental fish correlated with the high expression of IGF-1 and GH in the liver in that experiment.
In the present work, Nile tilapia showed the highest growth response to diets containing 80% F followed by 80% Q and 40% F compared to control. Saponins show a growth promoting effect in Nile tilapia although the best performance was achieved by a different fraction compared to carps.
Fish were kept in the chambers of a respirometric system and in parallel in aquaria of a recirculation system and fed for eight weeks. Every two weeks one animal per group from the aquaria was slaughtered to determine the hormone levels as well as the gene expression profile using semi quantitative Real Time-PCR (RT-PCR). The fish in the respirometric system were slaughtered at the end of the eight weeks to determine the feed conversion ratio and whole body chemical composition. In a previous experiment with the same treatments, saponin supplementation in the diet affected expression of IGF-1 and GH in C. carpio. The growth of the experimental fish correlated with the high expression of IGF-1 and GH in the liver in that experiment.
In the present work, Nile tilapia showed the highest growth response to diets containing 80% F followed by 80% Q and 40% F compared to control. Saponins show a growth promoting effect in Nile tilapia although the best performance was achieved by a different fraction compared to carps.
| Original language | American English |
|---|---|
| Pages | S12-S13 |
| Number of pages | 2 |
| State | Published - Sep 2008 |