The Biochemical composition of sea weeds from the persian gulf and the effect of sea weed extract on the growth and biochemical composition of microalgae cultured as live food for penaeus indicus larvae
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Date
2011
Authors
Ghadikolaei, Kiuomars Rohani
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Abstract
The biochemical composition of three groups of seaweeds; green ( Ulva lactuca
and Enthromorpha intestinalis ), brown (Sargassum illicifolium and Colpomenia
sinuosa) and red (Hypnea valentiea and Gracilaria corticata) from the Persian Gulf
and the effects of seaweed extracts (SWE) either as a supplement or as a substitute
media t'o the f/2 medium on the growth and composition of two microalgae
Isochrysis galbana and Chaetoceros muelleri cultured as live food for Penaeus
indicus larvae were investigated.
Results showed that seaweeds were relatively high in carbohydrate and ash, but
low in lipid. Lipid content in green ( U. lactuca and E. intestinalis) seaweed was
significantly higher than both the red and brown seaweed (P < 0.05). Protein content
of red (G. corticata) and green (U. lactuca and E. intestinalis) seaweeds was notably
higher than brown seaweed (P < 0.05). The green (U. lactuca) and red (H. valentiea)
seaweeds. had the highest proportion of saturated fatty acids, while the brown (S.
illicifolium and C. sinuosa) and red (G. corticata) seaweeds had the highest
proportion of monounsaturated and polyunsaturated fatty acids, respectively. The
mineral compositions 111 seaweeds were found 111 the sequence of
K>Mg>Fe>Zn>Mn>Cu>Co.
The study clearly showed that the two microalgae I. galbana and C. muelleri
could be successfully cultured using the various SWE either as a supplement or as an
he f/2 medium. Since no major changes were found in most of the
measured growth parameters, proximate biochemical composition, important
polyunsaturated fatty acids and minerals content following culture of the microalgae
with SWE as an alternative media, particularly extracts of U lactuca, E. intestinalis
and G. corticata, it was concluded that these SWE are able to provide the necessary
nutrients for microalgae growth and could be used as a possible substitute to reduce
microalgae production costs, at least two times lower than conventional f/2 medium,
in establishing microalgal populations to use in aquaculture operations.
The present study found that when P. indicus larvae were fed on microalgae I.
Jtalbana and C. muelleri (exclusively or mixed) that had been cultured with SWE as
a supplement media, they molted faster to mysis 2 (Mu) stage compared to the larvae
fed on microalgae cultured with conventional f/2 media (control without any SWE).
Maximum final total length, survival rate and specific growth rate were recorded for
shrimp larvae fed on microalgae diets that included SWE as a supplement in the
culture media compared to shrimp larvae fed the control diet. The overall growth
performance clearly showed that P. indicus larvae were successfully reared using
microalgae diets tested, and the shrimp larvae fed on mixed microalgae (1. galbana +
C. muelleri) showed better larval growth, survival and d-evelopment than those that
were fed on single microalgal diet. Furthermore, similar larval growth, survival and
development were obtained when shrimp larvae were fed with microalgae cultured
with SWE as a substitute media to f/2 medium. In conclusion, microalgae cultured
with SWE could potentially be used as a low-cost alternative method in producing
live food for the hatchery production of shrimp larvae.
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Keywords
Seaweed extract , Biochemical Composition , Microalgae cultured , Penaeus indicus