The development of a formulated feed containing Ulva (Chlorophyta) to promote rapid growth and enhanced production of high quality roe in the sea urchin Tripneustes gratilla (Linnaeus) |
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Authors: | Mark D Cyrus John J Bolton Lourens De Wet Brett M Macey |
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Affiliation: | 1. Botany Department and Marine Research Institute, University of Cape Town, , Rondebosch, South Africa;2. Feed Technology Project, Divison of Aquaculture, University of Stellenbosch, , Matieland, South Africa;3. Department of Agriculture, Forestry and Fisheries, Aquaculture Research and Development, , Roggebaai, South Africa |
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Abstract: | This study investigated growth and gonad production of Tripneustes gratilla fed four protein‐rich artificial diets supplemented with varying amounts (0%, 5%, 15% and 20% weight/weight (w/w); designated 0, 5, 15 and 20U, respectively) of the macroalga Ulva over a 12‐week period. Gonad size, texture, colour and a number of production performance parameters were quantified and compared with urchins fed fresh Ulva (FU) and a combination of FU and artificial feed (FB). All artificial diets significantly (P ≤ 0.05) increased gonad somatic indices (GSI) compared with the FU treatment. The 20U treatment increased GSI by 205% by week 9, compared with a 57% increase in the GSI of urchins fed FU. Gonad colour was calculated using three colour parameters, namely L* (lightness), a* (redness) and b* (yellowness). Whereas L* and a* values did not differ significantly between treatments, b* values for all treatments, with the exception of the 20U and FB treatments, were significantly (P ≤ 0.05) lower or less yellow than the FU treatment by week 12. These results show that we have successfully formulated a feed (20U) which can produce commercially acceptable gonads in terms of both size and colour, indicating the potential for this artificial feed to support commercial echinoculture. |
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Keywords: | Echinoculture
Tripneustes gratilla
formulated feed
Ulva
gonad colour gonad enhancement |
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