Abstract
The nutritional value to abalone of Ulva lactuca L. with different tissue nitrogen levels was studied. The Seaweed was cultured at two levels of ammonia-N enrichment. Cultures receiving 0.5 g ammonia-N m-2 d-1 ('low-N') yielded 164 g m-2 d-1 of fresh thalli containing 12% crude protein in dry matter and 12 kJ g-1 energy, cultures receiving 10 g ammonia-N m-2 d-1 ('high-N') produced 105 g of fresh thalli m-2 d-1 containing 44% protein and 16 kJ g-1 energy. High-N and low-N algae and a 'standard' mixed diet of 75% U. lactuca and 25% Gracilaria conferta (w/w) containing 33% protein and 15 kJ g-1 energy were fed to juvenile (0.7-2.1 g) and adult (6.9-19.6-g) Haliotis tuberculata and H. discus hannai in a 16-week feeding trial. Voluntary feed intake of the high-N and standard diets were significantly lower than the low-N diet in all the cases. Clear differences in performance between treatments were found in the juvenile and adult abalone of both species. Juveniles fed high-N and standard diets grew significantly faster (specific growth rate of H. tuberculata was 1.03% day-1 on high-N algae as compared to 0.72% on low-N algae; H. discus hannai grew 0.63 and 0.3% day-1 on high- and low-N algae, respectively) and showed much better food conversion ratios. The nutritional value of Ulva lactuca to abalone is greatly improved by a high protein content, attainable by culturing the seaweed with high supply rates of ammonia.
Original language | English |
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Pages (from-to) | 227-233 |
Number of pages | 7 |
Journal | Journal of Shellfish Research |
Volume | 18 |
Issue number | 1 |
State | Published - Jun 1999 |
Externally published | Yes |
Keywords
- Abalone
- FCR
- Integrated mariculture
- Nutrition
- Protein content
- Seaweed
ASJC Scopus subject areas
- Aquatic Science