|PD/A CRSP Twentieth Annual Administrative Report
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Subcontract No. RD010E-20
Florida International University, Miami, Florida
|Christopher L. Brown||US Principal Investigator|
|Emmanuel Vera Cruz||Graduate Assistant (Philippines)|
University of Hawaii, Manoa, Hawaii
|Robert Howerton||Associate Investigator|
|James Szyper||Associate Investigator|
Central Luzon State University, Muñoz, Nueva Ecija, Philippines
|Remedios B. Bolivar||Host Country Principal Investigator|
|Michael Aragones||Undergraduate Student (Philippines; partially CRSP funded from April 2002)|
|Joshue Ian B. Falla||Undergraduate Student (Philippines; partially CRSP funded through April 2002)|
|Jibb Maniego||Undergraduate Student (Philippines; partially CRSP funded from September 2001)|
|Michelle Zamora||Undergraduate Student (Philippines; partially CRSP funded from April 2002)|
This subcontract was awarded funding to conduct the following Tenth Work Plan investigations:
Note: In addition to the above investigations, Central Luzon State University also collaborates with University of Arizona (10NSR3E).
Falla, J.I.B., 2002. Hematological characteristics of genetically male tilapia (GMT) strain of Nile tilapia (Oreochromis niloticus) under intensive tank culture. B.S. thesis, Central Luzon State University, Philippines.
Bolivar, R.B. Overview of Tilapia Production in the Philippines. Presentation given at the International Technical and Trade Symposium on Tilapia at Hainan, Haikou, China, on 1722 April 2002.
Aquaculture America 2002 at San Diego, California, 2730 January 2002. (Bolivar, Sevilleja)
PD/A CRSP Annual Meeting at San Diego, California, 31 January 2002. (Bolivar, Sevilleja)
Asia Region Expert Panel meeting at Beijing, China, 23 April 2002. (Bolivar)
World Aquaculture 2002 at Beijing, China, 2327 April 2002. (Bolivar)
National Trainers Training on Freshwater Aquaculture Updated Technologies, BFAR-National Freshwater Fisheries Technology Center, BFAR, CLSU, Science City of Muñoz, Nueva Ecija, 2126 May 2002. (Bolivar)
An on-farm trial was conducted to evaluate the possible additive effects of combining two feeding strategiesdelayed onset of feeding and feeding at sub-satiation levelsin the culture of tilapia in ponds. The present study was based on results of the aforementioned feeding strategies (experiments 9FFR4 and 9FFR3, respectively), which independently showed that feed reduction was possible in tilapia grow-out production.
Ten farmers were enlisted for the on-farm trial. The first stage of feed reduction was through onset of supplemental feeding 75 days after stocking fingerlings in the ponds. The second stage was feeding the fish at 100 or 67% satiation. Satiation level was experimentally determined once a week in each farm by the project staff. The fish were given prepared feeds consisting of 67% rice bran and 33% fish meal (crude protein = 28.6%). Supplemental feeding was started 75 days after stocking fingerlings in the ponds. After 150 days of culture, the fish were harvested and the growth performance was compared between the two treatments.
Mean final weights of fish were 104 and 91 g for the 100 and 67% satiation feeding, respectively, but this difference was not statistically significant (P > 0.05). The general poor growth of the fish can be attributed to the low temperatures recorded during the on-farm trial. A simple cost-benefit analysis showed a negative net return in the 100% satiation treatment.
Emmanuel Vera Cruz, a member of the Central Luzon State University faculty, arrived with his family at the Florida International University in mid-August 2002 and is officially enrolled in the doctoral program in the Department of Biological Sciences. His doctoral research began immediately, and his studies will be based on the use of the insulin-like growth factor 1 (IGF-1) gene to develop molecular probes and to use them in the study of growth regulation in Nile tilapia (Oreochromis niloticus). This work begins as soon as new student orientation is concluded, and it will address all of the objectives in the Tenth Work Plan.
The IGF-1 gene of Nile tilapia has been cloned. Cloning has taken two attempts, both carried out at North Carolina State University in the laboratory of Russell Borski, a project collaborator. This process used primers developed to recog-nize short DNA sequences characteristic of the IGF-1 gene and possible fragments (isolated by electrophoresis) that appear to conform to the known properties of comparable genes already isolated from other species. The putative clone was then subjected to nucleic acid sequence analysis and compared with published sequences of known IGF-1s that are available online. Our first attempt was a non-confirming sequencethe sequence homology with IGF-1 was not sufficient to confirm the results of the isolation of the desired gene, and in fact it confirmed that the process had resulted in the isolation of an altogether unrelated sequence due to a recognition error by the primer. The second attempt was successful, and we now have a viable clone of the O. niloticus IGF-1 gene available for all of the proposed studies on the detection and expression of this gene. We believe we are on track for a successful project and doctoral program on the part of Vera Cruz.
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