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Märstetten-Dorf, Switzerland

Do Huu H.,University of Queensland | Do Huu H.,CSIRO | Do Huu H.,Institute of Oceanography | Tabrett S.,CSIRO | And 3 more authors.
Aquaculture | Year: 2013

Prawns have a dietary requirement for nucleotides for optimum growth. Commercial diets and many natural feed ingredients, including fishmeal are high in nucleotides, with guanine and its derivatives contributing the highest proportion of total nucleotide. The aim of this study was to test the role of guanine alone and in combination with other purified nucleotides on growth, survival rate and non-specific immunity of prawns using a supplemented semi-purified diet. Semi-purified diets as basal (or control) and basal diets supplemented with 0.4% GMP, 0.5% GMP and with combinations of 0.4% GMP with 0.1% of each of AMP, CMP, IMP or UMP were used to feed the prawns (initial mean weight of 3.83±0.01g) for 53days. Two positive control diets, one comprising the semi-purified diet supplemented with a commercial nucleotide mixture, Optimun at 2.27% (0.5% total nucleotide) and a commercial diet, Lucky Star, were also included. Supplementation levels were chosen based on the optimal total nucleotide content determined in previous trials with the semi-purified diet. Growth rates of prawn (DGC, %/day) were significantly higher in groups of prawn fed diets supplemented with 0.5% GMP, GMP+AMP, GMP+IMP than prawns fed the basal, 0.4% GMP, and GMP+UMP (p≤0.030). THC were highest in groups of prawns fed diets containing GMP+AMP, GMP+IMP, GMP+CMP and the basal diet supplemented with Optimun (32×106-33×106cells/mL) and were significantly higher than THC in groups of prawns fed basal diet and diet supplemented with 0.4% GMP alone (~26.5×106cells/mL) (p≤0.038). On day 52, concentrations of guanine, adenine, total purine and total nucleotide in prawn diets were highly positively correlated with weight of prawns (p≤0.013), whilst THC was significantly correlated with guanine, total purine and total nucleotide content (p≤0.023). Survival rates of prawns were very high (between 92 and 100%) and did not differ significantly among diet treatments (p=0.449). Purine nucleotides, especially guanine, appear to be critical for optimal growth of black tiger prawn, Penaeus monodon. © 2013. Source


Do Huu H.,University of Queensland | Do Huu H.,CSIRO | Tabrett S.,CSIRO | Hoffmann K.,Chemoforma Ltd. | And 3 more authors.
Aquaculture | Year: 2012

Nucleotides are essential to growth and development in mammals and some aquatic animals. Whilst much of the requirements for nucleotides can be met through de novo synthesis or salvage during cellular recycling, uptake through the diet is more energy-efficient. However, optimal dietary requirements are unknown for many species, and levels of nucleotide and their bioavailability in standard feed ingredients are largely unreported. The aim of this study was to determine the nucleotide requirement for maximal growth of black tiger prawn, Penaeus monodon. Initial dose-response trials using commercial mashes were confounded by high basal nucleotide levels therefore raw ingredients were analysed by HPLC for nucleotide content and a semi-purified diet was formulated with defined low nucleotide level. Using this as a base diet in a dose-titration study, results showed highly significant correlations between growth rates of prawns and concentrations of nucleotide in diets. Optimal nucleotide concentrations were predicted to be 0.564% at day 21 (R 2=81.03%), 0.455% at day 42 (R 2=88.19%) and 0.448 at day 63 (R 2=63.18%), indicating a declining requirement for nucleotides with the increase in prawn size. In conclusions, raw ingredient analysis and a feeding trial indicated optimal requirements for dietary nucleotide in black tiger prawns ranged from 0.56 to 0.44% w/w. It is likely that some, or all, of the requirements can be met through naturally variable nucleotide in fishmeal. However, as fishmeal levels are reduced, driven by economics and sustainability, supplementation is likely to be required for optimal performance. © 2012. Source

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