2012 Annual Report
1a.Objectives (from AD-416):
The goal of this agreement is to carryout a collaborative research effort among PBARC, The College of Agriculture, Forestry and Natural Resource Management (CAFNRM) at the University of Hawaii at Hilo (UHH), and the College of Tropical Agriculture and Human Resources (CTAHR) at the University of Hawaii at Manoa (UHM) that addresses important agriculture problems in Hawaii. The specific problem to address is determined through consultation and agreement among the agriculture college deans of CAFNRM and CTAHR and the director of PBARC. The main objective of this SCA is to evaluate the usefulness of regionally grown feedstock for aquaculture and livestock.
1b.Approach (from AD-416):
In 2002, congress provided a set amount of funds to PBARC with the mandate that the funds should be split three ways among CAFNRM, CTAHR, and PBARC. The intent is to develop a mutually beneficial collaborative research effort that is formulated by the deans and the director of PBARC. The deans of CAFNRM and CTAHR, and the director of PBARC met and agreed to develop a research effort to evaluate the usefulness of regionally grown feedstock and co-products for aquaculture and livestock. Each institute would focus on research areas in which they have strengths and which would move the institutions closer to achieving the stated objective. To carryout the research plan, each dean will put out a call for proposals to their respective colleges for grant proposals to address the objective over a five year period. The proposals will be reviewed and selected by the deans and the director of PBARC, and any advisors that they may choose. To ensure that the research is focused on the objective and to assess progress, the investigators of the selected grants, the deans, and the director will meet annually to evaluate the work. Following the annual meeting, changes in the research personnel or focus may take place if needed. PBARC will have a research effort towards this objective but it will not have a call for proposals since the funds originally allocated to PBARC became part of their base budget. To maintain a degree of flexibility, the deans may use a small part of the funds to support other projects that may not be directly related to the main objective.
The main objective of this SCA between PBARC and UH-Manoa’s College of Agriculture, Forestry and Natural Resource Management is to evaluate the usefulness of regionally grown feedstock for aquaculture and livestock; this understanding directly contributes to objective 2 of the in-house project.
Initial analyses of phytoplankton byproducts showed that the protein levels were acceptable for culturing such omnivorous species as tilapia and prawns, but for carnivorous species, additional supplements might be required. Conversion of organic materials by saprophages has gained popularity in the last decade and larvae of the black soldier fly, Hermetia illucens, have been shown to be capable of converting large amounts of organic waste into protein rich biomass. The larvae could serve as a substitute for fishmeal or fishfood.
Efforts using feral tilapia as substrate resulted in food conversion ratio of only 3.9±0.7% in live larvae. The low conversion rate was attributed to a large amount of indigestible matters (e.g., bones, scales) that remained. There is potential that biofuel byproduct based feeds may not fully support the growth potential of fish. Myostatin prodomain (MSTNpro) was reported to suppress the bioactivity of myostatin, a potent negative regulator of skeletal muscle growth. It was hypothesized that suppressing myostatin activity in tilapia by an immersion bath treatment with recombinant flounder MSTNpro would improve the growth of tilapia. However, based on this study, it is suggested that myostatin enhanced tilapia growth for a short period after the treatment, but this effect disappeared at an extended growth period beyond the 45th week.