Participating organizations (WP leader in bold): P2. FCPCT, P3. IRTA, P4. IOLR, P13. UNIBA and P18. CTAQUA
Preliminary studies have indicated that the essential fatty acids DHA, EPA and ArA improved survival, growth and stress resistance in grey mullet (Eda et al., 1990, Tamaru et al., 1992).
Task 13.1 Improvement of larval performance
Task 13.2 Determining mullet nutritional needs for improved weaning to a dry diet
Task 13.3 Determining grey mullet nutritional needs for a more cost-effective production
Task 13.4 Design adequate feeding regimes for brood stock to optimize reproduction success
Preliminary studies have indicated that the essential fatty acids DHA, EPA and ArA improved survival, growth and stress resistance in grey mullet (Eda et al., 1990, Tamaru et al., 1992).
Task 13.1 Improvement of larval performance
- Sub-task 13.1.1 Improvement of larval performance through adequate first feeding regimes. We will examine the effect of DHA/EPA/ArA ratio and Tau on larval and juvenile performance during rotifer and Artemia feeding prior to and following ("silvering") transition from carnivorous larva to herbivorous juvenile.
- Sub-task 13.1.2 Using the most effective DHA-taurine diet from (13.1) to investigate the effect of supplemental ArA on larval growth, survival, presence of urinary crystals, as well as synchrony in “silvering” during metamorphosis.
Task 13.2 Determining mullet nutritional needs for improved weaning to a dry diet
- Sub-task 13.2.1 Determine expression of Tau rate limiting enzyme; cysteine sulfinate decarboxylase (CSD) at various stages (larval and grow out). Samples will be taken from studies in Task 13.1.
- Sub-task 13.2.2 Determine expression of rate limiting enzyme of bile salt synthesis, cholesterol 7α-hydroxylase (CYP7A1) at various stages (larval and grow-out). Samples will be taken from studies in Task 13.1.
Task 13.3 Determining grey mullet nutritional needs for a more cost-effective production
- Sub-task 13.3.1 Effect of DHA/EPA/ARA ratio in non-fish meal grow-out diets on fish performance.
- Sub-task 13.3.2 Effect of four levels of Tau supplementation to best performing DHA/EPA/ArA non-fish meal grow out diet from 13.3.1 on fish performance.
- Sub-task 13.3.3 Comparing the effect of two types of potential soybean meals to be used in the IOLR grow out diet for grey mullet on growth, intestinal morphology and inflammation, peroxidation and antioxidant mechanisms and intestinal pathology. This study will compare the effect of two types of soybean protein meals to be used in the IOLR grow out diet for grey mullet.
- Sub-task 13.3.4 The selected feed from Sub-tasks 13.3.1, 13.3.2, 13.3.3 will be compared to the current feed on the market used for mullet culture and fed to adult mullet until gonadal maturation.
- Sub-task 13.3.5 Comparison of vegetable oil-no fish meal grow out diet with a n-3 HUFA rich fish meal finishing diet on the nutritional and organoleptic values of fish flesh and bottarga quality.
Task 13.4 Design adequate feeding regimes for brood stock to optimize reproduction success
- Sub-task 13.4.1 Broodstock dietary effects on mullet reproduction (e.g., natural pigments, DHA/EPA/ARA ratio, Tau) on egg quality, in terms of fecundity, hatching success, and larval first feeding.
- Sub-task 13.4.2 Definition of specific requirements of protein, TAU, ARA, DHA and carotenoid sources to optimize spawn quality in mullet.
