Improving feeds and feeding for small scale aquaculture in Vietnam and Cambodia

Objective 1a: Develop diets based on locally-available ingredients for improved production of catfish and tilapia. Progress has been made in collecting a range of ingredient samples for a collective ingredient database. Composition of samples collected is yet to be determined. We are waiting for a critical number of samples to allow analysis of all samples together. This will begin in July 2005. Determination of the nutritional value of key ingredients will begin in July 2005 following a group methodology workshop in Can Tho in June 2005.

Objective 1b: Nutritional requirements of fish species in Vietnam & Cambodia.
Growth data and samples of tilapia and catfish from commercial farms have been collected in both northern and southern Vietnam. We are unable to confirm data and/or sample status from Cambodia due to poor communication links. Data collected and samples yet to be analysed, will be used in constructing preliminary factorial growth models in June 2005. This data review will also allow for data assessment to identify data gaps where further samples and/or farm data are required. Maintenance energetics trials on tilapia and catfish have been conducted in northern and southern Vietnam. Sample analysis from these trials is also pending. Only an energy utilisation efficiency trial is required for both tilapia and catfish to enable the initiation of complete energetic models for these species.

Objective 1b: Nutritional requirements of barramundi in Australia.
First growth trial delayed due to late appointment of post-doctoral and technical staff. First growth trial planned for July 2005. Existing growth and respiratory models refined, but waiting validation of higher temperature data to progress these models further.

Objective 1c: Diet formulation for catfish, tilapia and barramundi.
Formulations not yet progressed as it is premature to develop iterative diet designs before completion of growth models, maintenance and growth energetic data assessments. This objective is not expected to be met until year 3

Objective 2a: Demonstrate/evaluate the potential of new improved feeds in on-farm trials.
Not yet planned. Progressing this objective is still premature. Progress against this objective is planned for years 2 and 3 of the project.

Objective 3a: Transfer technology and extend information.
Workshops among the project participants were held in September 2004 and more are planned for June 2005. These workshops serve to develop technical capacity in the partner country collaborators and also review existing data-sets collected.

Objective 1a: Develop diets based on locally-available ingredients for improved production of catfish and tilapia. Progress has been made in collecting a range of ingredient samples for a collective ingredient database. Including the source history and diversity of species involved in some resource (trash-fish). Composition of samples collected has been determined. Determination of the digestible value of eight key ingredients has been determined.

Objective 1b: Nutritional requirements of fish species in Vietnam & Cambodia.
Growth data and samples of tilapia and catfish from commercial farms have been collected in both northern and southern Vietnam. Data and/or sample status from Cambodia has been poor, but has significantly improved with the location of an Australian Volunteers International (AVI) person (Mr Daniel Wright) with the group. Some experiments were re-run during 2005-2006 based on the assessment of data in November 2005. Data collected and samples have been analysed and will be used in constructing preliminary factorial growth models in August 2006. This data review will also allow for data assessment to identify data gaps where further samples and/or farm data are required for completion of the models by November 2006. Maintenance energetics trials on tilapia and catfish were re-run in both northern and southern Vietnam. Sample analysis from these trials has also been completed. Energy utilisation efficiency trial completed for catfish.

Objective 1b: Nutritional requirements of barramundi in Australia.
First and second growth trials completed. The first trial examined growth of barramundi at two size classes (20g and 140g) from 23 to 38C. The second trial forms block 1 of a two-block study examining the metabolic energy demand across the same temperature range, but uses animals from 10g to 500g. The existing growth and metabolic models developed by Dr Glencross have been refined based on the higher temperature data derived from experiment 1 and 2.

Objective 1c: Diet formulation for catfish, tilapia and barramundi.
Preliminary formulations have been provided to some collaborators, but have not yet progressed to the development of iterative diet designs before completion of growth models based on the maintenance and growth energetic data assessments. This objective is not expected to be met until year 3.

Objective 2a: Demonstrate/evaluate the potential of new improved feeds in on-farm trials.
Final component of the project. Plans for development of field strategies to examine this will be developed during the Nov 2006 site visits. Further progress against this objective is still premature until complete bio-energetic models have been developed. These models will be preliminary examined in August 2006, with further completion in Nov 2006. Progress against this objective is planned for years 2 and 3 of the project.

Objective 3a: Transfer technology and extend information.
Workshops among the project participants were held in Can Tho in June 2005. These workshops provided the participants with a greater degree of detail in the basis behind the models being developed, as well as the steps and techniques required to build their own models. Time was also spent with each of the partner country collaborators present reviewing their existing data-sets collected.

Objective 1a: Develop diets based on locally available ingredients for improved production of catfish and tilapia. Further progress has been made in collecting a range of ingredient samples for a collective ingredient database for Vietnam and Cambodia. The data includes the source history, diversity of species involved in some resources (e.g. trash-fish), price variability and nutritional composition. Determination of the digestible value to Pangasius catfish of eight key ingredients has been determined.

Objective 1b: Nutritional requirements of fish species in Vietnam & Cambodia.
Growth and temperature data, and samples of tilapia and catfish from commercial farms for development of fish growth models have been collected in both northern and southern Vietnam. Data and/or sample collection progress from Cambodia has been limited, but has significantly improved with the location of an Australian Volunteers International (AVI) person (Mr Daniel Wright) with the group. Maintenance energetics trials on tilapia and catfish were successfully re-run in both northern and southern Vietnam. Sample and data analysis from these trials has also been completed. Energy utilisation efficiency trial has been completed for catfish, but was not successful for tilapia. A functional factorial bio-energetic model for catfish has now been constructed and has been used to iteratively define nutritional protein and energy requirements for this species. Tilapia model remains to be constructed pending re-evaluation of data limitations.

Objective 1b: Nutritional requirements of barramundi in Australia.
All growth model studies have been completed and the existing growth and metabolic models developed by Dr Glencross are presently being further refined based on the higher temperature data derived from earlier experiments as new knowledge is gained. Two additional studies have been undertaken, one to validate some outputs of the model and another to examine the nutritional potential of alleviating heat-stress in fish.

Objective 1c: Diet formulation for catfish, tilapia and barramundi.
Iterative diet designs have been derived from the catfish and barramundi models. This has led to the formulation of a series of diets based on the ingredient assessment work and these revised diet specifications. These diets are presently being tested with catfish. Based on outcomes from the barramundi model the use of high-energy diets for large barramundi has been examined and shown to provide a significant advantage to production efficiency.

Objective 2a: Demonstrate/evaluate the potential of new improved feeds in on-farm trials.
Diets based on the ingredient evaluation and nutritional modelling of protein and energy demands of catfish are presently being tested in laboratory at Can Tho University. This work will be extended to farms and feed mills pending the outcome of the work. Further follow up assessment is required to review the outcomes of this validation trial.

Objective 3a: Transfer technology and extend information.
A three-day workshop was held at Can Tho University - College of Aquaculture and Fisheries in June 2005. This workshop focussed on coordinated analytical methods, background to bio-energetic/factorial modelling research approaches and review of collaborator data and workshopped design of new experimental protocols.
A four-day Aquaculture Nutrition Masterclass Shortcourse was held at Can Tho University - College of Aquaculture and Fisheries in March 2007. This Shortcourse focussed on dissemination of general aquaculture nutrition science and project findings to researchers, farmers and feed manufacturers from Southern Vietnam and Cambodia. Course content also included field visits to fish farms, feed mills, laboratories and practical formulation classes.
Outcomes of the research were also presented at the World Aquaculture Society Conference in Hanoi, Vietnam in August 2007.

Objective 1a: Develop diets based on locally available ingredients for improved production of catfish and tilapia.
A large a range of ingredient samples were collected in northern (HaiDuong and HaiPhuong prefectures) and southern Vietnam (Cantho, An Giang, Bac Lieu and Ca Mau prefectures) and in Cambodia and analysed for their nutritional composition. This data is presently being collated for a collective ingredient database for Vietnam and Cambodia. The data includes the source history, diversity of species involved in some resources (e.g. trash-fish), price variability and nutritional composition. Determination of the digestible value to Pangasius catfish of eight key ingredients has been determined.

Objective 1b: Nutritional requirements of fish species in Vietnam & Cambodia.
Regular weight and temperature data, and samples of tilapia and catfish were collected from commercial farms in both northern and southern Vietnam. This data has been analysed to underpin the development of fish growth models that can predict fish growth based animal size and water temperatures. Similar attempts at data collection in Cambodia have been limited, but has significantly improved with the location of an Australian Volunteers International (AVI) person (Mr Daniel Wright) with the group. A series of bio-energetic studies on both tilapia and catfish were successfully undertaken in both northern and southern Vietnam. These trials showed that metabolic energy demands by catfish and tilapia are similar to most other fish species and occur at a function not dissimilar to a.X0.8, where a is a temperature related coefficient of maintenance energy demand and X is the fish's live-weight. Energy and protein utilisation efficiency was also examined for catfish, but was not successful for tilapia. This study has shown that catfish does not use protein as efficiently as carnivorous species like barramundi. A functional factorial bio-energetic model for catfish has now been constructed and has been used to iteratively define nutritional protein and energy requirements for this species. Tilapia model remains to be constructed pending re-evaluation of data limitations.

Objective 1b: Nutritional requirements of barramundi in Australia.
A series of growth studies were completed at temperatures ranging from 20C to 38C. The results were used to fortify existing growth and metabolic models developed by Dr Glencross are presently being further refined based on the higher temperature data derived from earlier experiments as new knowledge is gained. Two additional studies were undertaken, one to validate some outputs of the model with large fish and another to examine the nutritional potential of alleviating heat-stress in fish. Both studies have had positive outcomes demonstrating practical applications of the model in predicting nutritional responses and that heat-stress can be partially alleviated using some nutritional design strategies.

Objective 1c: Diet formulation for catfish, tilapia and barramundi.
Iterative diet designs (those that have been "reverse engineered based on nutritional demands for energy and protein rather than formulated based on dose-response studies) have been derived from the catfish and barramundi models. This has led to the formulation of a series of diets based on a combination of the ingredient assessment work and these revised diet specifications. These diets were tested with catfish and barramundi. Based on outcomes from the barramundi model the use of high-energy diets for large barramundi has been examined and shown to provide a significant advantage to production efficiency.

Objective 2a: Demonstrate/evaluate the potential of new improved feeds in on-farm trials.
Diets based on the ingredient evaluation and nutritional modelling of protein and energy demands of catfish were tested in laboratory at Can Tho University. The new diets based on work from the project were compared against a traditional trash-fish/ricebran feed and also a commercial diet. The results showed that the new diet formulations produced fish that grew faster with a more efficient use of feed. These feeds and feeding strategies are now being tested in on-farm feeding trials. Following this the results will be extended to farms and feed mills.

Objective 3a: Transfer technology and extend information.
A two-day workshop was held at Can Tho University - College of Aquaculture and Fisheries in June 2005. This workshop focussed on coordinated analytical methods, background to bio-energetic/factorial modelling research approaches and review of collaborator data and workshopped design of new experimental protocols.
A four-day Aquaculture Nutrition Masterclass Shortcourse was held at Can Tho University - College of Aquaculture and Fisheries in March 2007. This Shortcourse focussed on dissemination of general aquaculture nutrition science and project findings to researchers, farmers and feed manufacturers from Southern Vietnam and Cambodia. Course content also included field visits to fish farms, feed mills, laboratories and practical formulation classes.
Outcomes of the research were also presented at the World Aquaculture Society Conference in Hanoi, Vietnam in August 2007. A total of six papers from the project were presented at this conference. Dr Glencross and Dr Nguyen also chaired sessions on fish meal replacement and catfish nutrition respectively.
In March 2008 a two-day extension workshop on fish nutrition and feed management was held at the Phu Tao Field Station in Hai Duong prefecture. In addition to the day and half of lectures a half day field trip to tilapia farms in the prefecture to view feed manufacture and feeding practices was also undertaken.