Now showing items 1-5 of 5

    • Article

      Growing the reproductive cells (carpospores) of the seaweed, Kappaphycus striatum, in the laboratory until outplanting in the field and maturation to tetrasporophyte 

      MRJ Luhan & H Sollesta - Journal of Applied Phycology, 2010 - Springer Verlag
      Carposporophytes of the seaweed, Kappaphycus striatum, from the wild were made to shed spores in the laboratory and grown in multi-step culture method until they reached maturity. For each succeeding transfer onto increasingly bigger culture vessels, there was a marked increase in the growth of carposporelings. When plantlets were ready for outdoor culture, they were placed in aquaria and concrete tanks and later moved to the sea in net cage and long-line for grow-out culture. Successfully growing sporelings from carposporophytes in the laboratory until they reach market size seems to depend on the stage of sporelings and environmental factors such as photoperiod and temperature. In this study, carpospore progenies (diploids) also matured into tetrasporophytes and haploid progenies showed resistance to higher temperature.
    • Article

      Growth and carrageenan quality of Kappaphycus striatum var. sacol grown at different stocking densities, duration of culture and depth 

      AQ Hurtado, AT Critchley, A Trespoey & G Bleicher-Lhonneur - Journal of Applied Phycology, 2008 - Springer Verlag
      Kappaphycus striatum var. sacol was grown in two separate studies: (1) at two stocking densities, and (2) at four different depths, each for three different durations of culture (30, 45 and 60 days) in order to determine the growth rate of the seaweed and evaluate the carrageenan content and its molecular weight. The results demonstrated that stocking density, duration of culture and depth significantly (P < 0.01) affected the growth rate, carrageenan content and molecular weight of K. striatum var. sacol. Decreasing growth rate was observed at both stocking densities and at four depths as duration of culture increased. A lower stocking density (500 g m–1line–1) showed a higher growth rate for the shortest durations, i.e. 30 days, as compared to those grown at a higher density. Likewise, decreasing growth rate was observed as depth increased, except at 50 cm after 60 days of culture. A 45-day culture period produced the highest molecular weight at both stocking densities (500 g m–1line–1 = 1,079.5 ± 31.8 kDa, 1,000 g m–1line–1 = 1,167±270.6 kDa). 'Sacol' grown for 30 days at 50 cm (1,178 kDa) to 100 cm (1,200 kDa) depth showed the highest values of molecular weight of carrageenan extracted. The results suggested that K. striatum var. sacol is best grown at a stocking density of 500 g m–1line–1, at a depth of 50-100 cm, and for a duration of 30 days in order to provide the highest growth rate, carrageenan content and molecular weight.
    • Potentials of Kappaphycus striatum (Schnitz) and Gracilaria heteroclada Zhang (Ad Xia) to control the growth of luminous bacteria Vibrio harveyi 

      EA Tendencia & MR de la Peña - The Philippine Agricultural Scientist, 2010 - University of the Philippines Los Baños
      Different aquaculture species such as finfishes and bivalves have been reported to control the luminous bacterial disease of shrimp, usually caused by Vibrio harveyi. The use of seaweeds in shrimp culture system has reportedly improved water quality and reduced the bacterial count. This study evaluated the potentials of two species of seaweeds, Gracilaria heteroclada (Ad Xia) and Kappaphycus striatum (Schnitz), to control the growth of V. harveyi.

      V. harveyi was inoculated into control tanks containing shrimps only and into treated tanks containing both shrimp and macroalgae. Luminous bacterial counts were monitored daily. From day 2 to day 6, luminous bacterial count in tanks with G. heteroclada was significantly lower than those in tanks with K. striatum. Bacteria isolated from the rearing water containing K. striatum and G. heteroclada and from the seaweed homogenized in sterile seawater showed anti-Vibrio harveyi activity. The seaweed homogenate per se also showed anti-luminous bacterial property. Presence of both G. heteroclada and K. striatum in shrimp culture system has the potential to control the growth of luminous bacteria. G. heteroclada was more efficient and sustainable, as shown by the lower luminous bacterial count and the higher percentage recovery of this macroalga after 11 d in experimental tanks.
    • Conference paper

      Seaweed research at SEAFDEC Aquaculture Department 

      AQ Hurtado - In AQ Hurtado & MRJ Luhan (Eds.), Proceedings of the National Seaweed Symposium, September 3-4, 2002, Cebu City, 2003 - Seaweed Industry Association of the Philippines
      Seaweed research at the Aquaculture Department of SEAFDEC focuses mainly on 2 genera of agarophytes (Gracilaria and Gracilariopsis) and carrageenophytes (Eucheuma and Kappaphycus).

      From 1988 to 1998, research works were mainly on Gracilaria and Gracilariopsis along these areas: (1) refinement of culture technique, (2) basic biology, production ecology, and corp management, (3) product utilization, (4) screening and characterization of natural products, and (5) economics of farming system.

      Four years ago, the Seaweed Program of the Department re-focused its thrust on Advanced Aquaculture Technologies (Biotechnology) to include also Eucheuma and Kappaphycus in answer to the needs of the industry.

      This paper briefly describes the highlights of the different studies done on biotechnology.
    • Article

      Use of Acadian marine plant extract powder from Ascophyllum nodosum in tissue culture of Kappaphycus varieties 

      AQ Hurtado, DA Yunque, K Tibubos & AT Critchley - Journal of Applied Phycology, 2009 - Springer Verlag
      Three varieties of Kappaphycus alvarezii (Kapilaran, KAP), Tambalang purple (PUR), Adik-adik (AA), and one variety of Kappaphycus striatum var. sacol (green sacol (GS) were used to determine the efficiency of Acadian marine plant extract powder (AMPEP) as a culture medium at different concentrations, for the regeneration of young plants of Kappaphycus varieties, using tissue culture techniques for the production of seed stock for nursery and outplanting purposes for the commercial cultivation of carrageenophytes. A shorter duration for shoot formation was observed when the explant was treated with AMPEP + Plant Growth Regulator (PGR = PAA + zeatin at 1 mg L−1) compared to AMPEP when used singly. However, four explants responded differently to the number of days required for shoot formation. The KAP variety took 46 days to form shoots at 3–4 mg L−1 AMPEP + PGR; while PUR required 21 days at 3–5 mg L−1 AMPEP and 3–4 mg L−1 AMPEP + PGR. AA required 17 days at 3–5 mg L−1 AMPEP and AMPEP + PGR; and GS 25 days at 1 mg L−1 AMPEP + PGR. It was observed that among the four explants used, PUR and AA initiated shoot formation with the use of AMPEP only at higher concentrations (3–5 mg L−1) after a shorter period. Only PUR responded positively to ESS/2 for shoot initiation. The use of AMPEP alone and/or in combination with PGR as a culture medium in the propagation of microplantlets using tissue culture technique is highly encouraging.