Browsing by Author "Ramos, Angela"
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- Biotechnology in aquaculture: polyploidy versus transgenic technologyPublication . Ramos, Angela; Power, DeborahTriploidy is the condition in which somatic cells contain three sets of chromosomes which might be a consequence of environmental changes or hybrid stabilization, though in the present work the ploidy induction was done by hyperbare pressure. Diploid and triploid Rainbow trout, Onchorynchus mykiss (Walbaum, 1792) were the species characterized in this thesis. Besides ploidy a modification in the mineral availability of phosphorous, was applied influencing the whole body mineral homeostasis in diploid and triploid trout. The skeletogenesis in triploids animal is different from the diploid, having a general delay, the mineral deficient diet has also an impact on the ossification retreating. It allowed studying the development through triploids, which at the end of this trial they grew less than diploids. Vertebra area is also affected varying acconding to their regions, total number of vertebra differs, and in average triploids have less one vertebra than diploid groups. And there are also histological differences at a muscle level, having triploid Diet A less myotomes in average. Animals present a high capacity in recovering, once they start eating a normal diet in mineral composition, the restore their mineral content in bone structures in some situation an over calcification is observe (Diploid A). In a molecular level, there were any molecular differences observed only a high variability at the OSN levels.
- Effects of dietary phosphorus and calcium level on growth and skeletal development in rainbow trout (Oncorhynchus mykiss) fryPublication . Fontagné, Stéphanie; Silva, Nadia; Bazin, Didier; Ramos, Angela; Aguirre, Peyo; Surget, Anne; Abrantes, António; Kaushik, Sadasivam J.; Power, DeborahThe effects of dietary levels of phosphorus (P) and calcium(Ca) on skeletal development and mineral deposition in rainbow trout(Oncorhynchus mykiss) fry were studied. Six semi-purified diets were formulated with graded levels of P and Ca. The basal diet A contained only P supplied by casein at 0.5% of drymatter. Other diets B, C,D and Ewere supplementedwith 0.4, 0.8, 1.2 and 1.6% P supplied as a 1:1 mixture of NaH2PO4/KH2PO4 resulting in 0.8, 1.2, 1.6 and 2.2% total P, respectively. These five dietswere supplementedwith 1% Ca supplied as CaCO3whereas another diet F, supplementedwith 0.8% P,was Ca-free. Each dietwas distributed to 3 replicate tanks of 600 swimup fry (initialmean weight: 0.1 g) at a water temperature of 17 °C over a 12-week growth trial. Fish were handfed 6 times a day to visual satiety.