REPORT OF THE WORKSHOP ON SHRIMP AND FINFISH
FEED DEVELOPMENT
Johore Bahru, Malaysia
25–29 October 1988
1.1 As one of the activities of RAS/84/016, a regional Workshop on Shrimp and Finfish Feed Development was organized on 25–29 October 1988, hosted by the Government of Malaysia.
The Workshop was officially opened by Encik Mohd. Mazlan bin Jusoh, the Deputy Director General of Fisheries, Malaysia.
In his official address the Deputy Director General of Fisheries congratulated the ASEAN/UNDP/FAO Regional Small-Scale Coastal Fisheries Development Project and the Department of Fisheries Malaysia for jointly organizing the Workshop which he felt was timely for the development of the aquaculture industry in the ASEAN region. He hoped that the Workshop would successfully deliberate on issues pertaining to the role played by the feedmilling industry in assisting the development of the aquaculture industry.
He said many countries had embarked on aquaculture development particularly of tiger prawns, as a source of foreign exchange. In order to have a competitive edge over others, production costs must be kept low. As feed contributes about half of production costs; the Workshop should look into this important constraint.
The Malaysian Government is emphasizing on aquaculture development as a source for fish and prawn production and as a foreign exchange earner. Rapid achievements in this field and further potential for development will create a big demand for both formulated shrimp feed and trash fish. There is, therefore, a need to look into whether the existing feedmillers and trash fish resources can meet the expected demand for feeds in the future.
At the moment most shrimp feeds are imported from overseas. The future expansion of cage culture will depend on trash fish available. As these resources are limited, there is a need to look for alternative feeds so that expansion of cage culture industry will not be hampered.
There is still considerable scope for development in feeds production particularly in the quality of local ingredients produced and its cost competitiveness with foreign feed materials.
Encik Mazlan pointed out that the Fisheries Department of Malaysia had given much emphasis to the development of suitable formulated diets for various aquaculture species. The Department had established several feed research facilities under the Fisheries Research Institute. He elaborated on some achievements that had been made and how the results were disseminated to target groups such as fish culturists, potential investors and feedmillers. He expressed his hope that while the government is playing a lead role in pioneering the development of formulated feeds, the private sector would take over in commercializing them to meet the growing demand of the rapidly expanding private industry and possibly for export, too. He called upon the private sector to work together with the government sector for the bright future of feedmilling and aquaculture industries in their respective countries.
His full address is in Annex 1.
1.2 The Workshop was attended by fisheries scientists and extension workers of the ASEAN countries and resource persons from the private sector and international bodies from the region.
The list of participants is in Annex 2.
1.3 The Project Coordinator, Mrs. Medina N. Delmendo, in her address expressed the hope that the Workshop would attempt to find answers to problems of feeds for aquaculture use and come up with suitable programme of action.
She welcomed the presence of Mr. Michael New, an expert on fish nutrition and Programme Coordinator of the ASEAN/EEC Aquaculture Development and Coordination Programme (AsDCP) and the private sector in the Workshop and thanked the Department of Fisheries of Malaysia for hosting the Workshop.
1.4 The Workshop was chaired by Mr. Ong Kah Sin, Director of Fisheries Research Institute, Malaysia.
In his opening address he said that aquaculture is now accorded high priority because the technology and economic viability of various aquaculture systems had been well proven. Now the trend is towards the intensification of culture systems through further refinement of technology, particularly in the area of feed development. It is, therefore, timely to hold this Workshop so that leading workers in the ASEAN region could meet, share their experience and exchange ideas in this field.
He thanked the Project Coordinator, Mrs. Medina N. Delmendo, for having organized the Workshop.
His full address appears in Annex 3.
2.1 Of all the countries of the ASEAN region, Thailand is the only one self-sufficient in raw material feed ingredients supply with very minimum importation of compounded feeds, if any. All other countries import most of the raw feed ingredients or compounded feeds mainly from Taiwan. Thailand, however, is confronted with the lack of funds for research on fish nutrition requirements, feed technology and trained manpower for research.
2.2 Singapore on the other hand, while all the feed ingredients are imported, is leading the ASEAN countries in feed technology development. One of the reasons for this is the country's aim to establish technology to attract investment in various large intensive systems which can produce six times the small farm production.
2.3 The Workshop observed that at present there is no standard quality of formulated feeds for shrimp and finfish available in the market in the ASEAN region. This is due to the lack of knowledge about the nutritional requirements of species cultured in the area. Evaluation of feed based on crude protein levels alone is not an adequate measure of feed quality.
2.4 The rapid expansion of intensive shrimp farming operations in the region is already forcing increased competition for fish meal with livestock feeds, thus increasing market price. Alternative sources of protein other than raw materials of marine origin have to be found to avoid overdependence of fish meal utilization. This could be done either by protein sparing or the use of other protein sources.
2.5 Small farmers do not usually have the means to procure compounded feeds. It was, therefore, suggested that feed technology research to resolve the feed requirements of small-scale rural fish farmers producing fish for domestic consumption should be given appropriate attention. This would be particularly important considering the possibility in the near future of oversaturation of intensive shrimp culture for international market. Under such circumstances, there would be a necessity of expanding domestic market bases for the commodity. Home-made feeds using locally available raw materials should be considered.
2.6 In the light of shrimp and finfish feed problems confronting intensive aquaculture operations, semi-intensive aquaculture management systems would be a more viable alternative which might be an important consideration for planners and policy-makers.
2.7 For shrimp and finfish larvae rearing, live food organisms are still being used. There is a need to study the use of micro-particulate and encapsulated feeds for larvae, their nutritional efficacy and economics.
2.8 For the grouper larvae, research conducted in Thailand showed that rotifers could be used effectively for rearing 1–10 days old grouper larvae. After this period, they could subsist on Artemia nauplii.
2.9 For grow-out of finfish (except tilapia and carp), trash fish and semi-moist pelleted feeds are used; pelleted and minced trash fish are used for shrimps in Singapore.
2.10 For dry pelleted feed, the FCR of seabass in experimental tanks was 1.2:1. Studies conducted in Singapore showed that the optimal dietary protein requirement of seabass in the early grow-out stage (71–181 g) was found to be between 40–45 percent with the use of single protein reference diets containing protein derived entirely from fish meal. Experiments to determine performance of two practical dry formulations made from multiple protein sources on seabass of the same population showed that cheaper local formulation containing 43 percent protein and 12 percent fat performed better than the imported ration with 50 percent protein and 16 percent fat. The local feed formulation showed better protein utilization rates than the imported feed and trash fish.
2.11 In Thailand the use of minced fish flesh with artificial diet on grouper was found significantly higher than the use of minced fish flesh alone. From the data given on the cost of feeds used, it was indicated that the cost of feed to produce 1 kg of grouper was Baht 36 for the 45 percent diet; Baht 39 for the 50 percent diet and Baht 37 for the 55 percent diet. For minced fish flesh alone, it would cost about Baht 55 to produce a kilogram of grouper. The results of trials conducted in Singapore using fish flesh were, however, not encouraging. It was found that groupers could be trained to take hard pellets but a large population would be necessary to be successful.
2.12 A survey of shrimp feeds (Kwan Foo Seong, Malaysia) showed two different grades and prices, one ostensibly for starter and the other for grow-out. Both had exactly the same amino acid profile. This observation was confirmed by findings in the Philippines.
2.13 Feed millers' commitment to shrimp feed manufacture, the Gold Coin in particular, is evident by its research and development programme; computerization of operation and increase in manpower has been made.
2.14 Experimental trials were conducted in Indonesia on shrimp feed development for larvae, post-larvae and grow-out in an attempt to replace the more expensive imported feeds. For grow-out purposes, formulations using a combination of squid and soybean meal showed best result; for post-larvae, brine-shrimp flake was found effective; for larvae artificial feeds made of local ingredients were developed. These trials were preliminary in nature. It was recommended that further tests with replications should be made to obtain more conclusive data.
2.15 In the Philippines, formulated feeds for Penaeus monodon were developed at SEAFDEC Aquaculture Department (AQD). It was reported that the quality of protein or amino acid profile of a diet is a necessary information in the development of shrimp feeds. The closer the essential amino acid pattern of the diet is to that of species under study, the more effective the diet becomes for growth. The nutrient requirements of P. monodon were studied at the AQD and suggested levels were given.
2.16 At present there is no single formula of shrimp feed that can be considered “best”. A farmer could, therefore, plan or formulate a diet to meet his needs. Some suggested formulations were also given and a few tips on how to formulate feeds were presented as a guide to shrimp farmers.
2.17 It was also reported that under the extensive shrimp culture, the cost of shrimp feeds per kilogram was Pesos 3.35 (US$0.17); under the modified extensive method (MODEX), Pesos 33.95 (US$1.70); semi-intensive and intensive methods Pesos 44.80 (US$2.24). The composition of feed cost to total operating cost was also found to be 8 percent for the extensive culture system; 55 percent for MODEX; 60 percent for semi-intensive and 55 percent for intensive operations. Analysis of all four systems showed financial profitability. However, taking into account the time value of money, the extensive system is not economical; the MODEX, semi-intensive and intensive methods are profitable when market conditions are stable. On the other hand, the MODEX and intensive systems are very sensitive to dynamic changes in the input/output markets and that the semi-intensive system is more stable despite such changes (Pascual, 1988).
2.18 Further research on the use of indigenous feed ingredients and fish nutritional requirement studies should be made to lower the cost of feeds and increase the profit of small farmers.
2.19 Attempts were made in Indonesia to use locally available plant material as feed ingredients for feeding red tilapia. These are Lemna and Salvinia spp., both aquatic weeds that are found abundant in freshwater systems. These aquatic plants are fermented with Sacharomycea and mixed with fish silage. Four kinds of formulated feeds using fermented ingredients and various protein sources were compared with commercial feeds.
2.20 Fermentation of the weeds improves digestibility while the yeast increases the crude protein content of the weeds. Results obtained indicated better performance of Lemna sp. than Salvinia sp.
2.21 The study was preliminary in nature; it was suggested that the diets should be isonitrogenous for better comparative results.
2.22 The Workshop felt that the common problem confronting the shrimp and finfish feeds development in the ASEAN region is the lack of knowledge on nutritional requirements of various species used for aquaculture. There is, therefore, a general need to undertake cooperative nutritional studies of culture species. The methodology for research should be standardized for comparability of results.
2.23 Nutritional studies should be devoted to species which are already in commercial production.
2.24 Experimental design is essential so as not to waste research efforts and scarce resources. For this purpose, it was recommended that technical advice of experts in this field within the region should be sought at the planning stage of research.
2.25 Alternatives to fish meal in aquaculture diets should be sought to lessen the demand and dependence on limited supply of fish meal.
2.26 The Workshop also felt that research on post-harvest handling of feed ingredients should be intensified to ensure a more consistent quality and supply of feedstuffs. Furthermore, there is a need to improve the present utilization of feed ingredients. Applied research should be geared towards increasing the efficiency of utilization of various feed ingredients particularly trash fish. The use of trash fish alone is wasteful as it does not exploit the possibility of protein sparing by other energy sources.
3.1 A general paper entitled “Formulated Aquaculture Feeds in Asia: Some Thoughts on Comparative Economics, Industrial Potential, Problems and Research Needs in Relation to the Small-Scale Farmer” was presented by Mr. Michael New.
In this paper, he discussed various aspects of the comparative economics and efficacy of different feeds and feed ingredients.
* Full text of all the technical/country review papers is found in Part II of the Report.
The author began by questioning existing methods of evaluating feed efficacy. He suggested that the use of Annual Profit Index (API) would be a better guide than the traditional Feed Conversion Ratio (FCR) in establishing the usefulness of a feed, both economic and technical, since the Annual Profit Index would address the specific considerations of the farmer and take into account his management constraints. The author also discussed the growth of compounded aquaculture feed manufacture in Asia. In particular, Thailand is poised to become a major producer of aquaculture feeds, particularly shrimp feed in the region. He estimated that by the year 2000, up to 830 000 tonnes of shrimp feeds may be produced in Asia, servicing a shrimp industry having a farm gate value of $6 300 million. This did not include compounded feeds manufactured for the finfish farming industry. The explosive growth of the industry has seen the entry of feedmills that produced feeds of dubious quality. Many farmers have complained that the growth rates they obtained did not match the manufacturer's claims.
The need for home-made feeds for small farmers was also addressed since it was an efficient way of using locally available raw materials.
Among the problems and priorities the author pointed out were; firstly, the requirements for ingredients of marine origin. The growth of the aquaculture feedmilling industry would be matched with a concurrent increase in fish meal utilization. Alternatives have to be found to avoid overdependence, either by sparing protein or use of non-traditional animal protein sources. Aquacultural growth is already forcing fish meal prices up and affecting the cost of poultry feeds in Thailand.
Secondly, it is important that feed technology research directs itself to resolving the requirements of small-scale rural farmers who produce fish for domestic market consumption. Such technologies would also need to consider the possibility of oversaturation of the international shrimp market and the necessity of expanding domestic market bases for the commodity.
Thirdly, there was a necessity to take into account the need to conserve scarce supplies of feed ingredients taking into account not only aquaculture requirements but the animal husbandry industry as well.
Finally, Mr. New posed a number of questions for consideration during the Workshop.
Discussion
Mr. Pathmasothy asked what alternatives there were to fish meal as an animal protein source. Mr. New replied that there are many possible alternatives such as bone meal, meat meal, blood meal, offal, etc. However, the economics, availability and quality of these substitutes have to be studied vis-a-vis their inclusion in aquaculture diets.
Mrs. Sariati requested clarification as to the quality of some Taiwanese feeds. Mr. New clarified that while some feeds had been reported to be of dubious quality, feeding techniques also play a role in establishing the efficiency of the feed. In the ensuing discussion, several observers confirmed that extraneous factors such as pond management, water quality and storage could affect the effectiveness of a feed adversely.
Mr. Hambal Hanafi asked whether in the light of the feed problems facing intensive aquaculture, semi-intensive or extensive cultures would be a viable alternative. Mr. New replied that this might be an important consideration for planners and policy-makers. The intensity of culture should tie in with the resources available in a particular country.
Mr. Kwan commented that in his surveys, he had come across shrimp feeds in two different grades and prices; one, ostensibly for starter and the other, grow-out having exactly the same amino acid profile. Dr. Pascual confirmed these observations. Mr. New also questioned whether such a wide variety of particle sizes as offered by feed manufacturers were necessary.
To a question by Mr. Ung, Mr. New clarified that the use of new Vitamin C analogues are still very experimental. However, Mrs. Chou felt that protected Vitamin C would be very useful as an anti-stress agent particularly for obviating transport stress. Since most of the Vitamin C now used in compounded feed is lost during processing, improvement in the processing technique should be made. However, some observers felt that more research would have to be carried out before the efficacy of the analogues are established.
Mr. Tang asked whether synthetic amino acids could be used to improve quality of non-traditional animal protein sources. Mr. New stated that amino acid supplementation are already being done.
Mr. Ung remarked that while Charoen Pokphand in Thailand used extrusion methods initially for shrimp feed production, they subsequently reverted to normal pelleting. Mr. New agreed that while at one time extrusion equipment was very expensive, prices have been dropping of late and extrusion may be more economically feasible in the future.
Mr. Tang brought up the problem of establishing on-farm efficacy of compounded feed. Mr. New agreed that there is no existing system by which the manufacturers' claims may be confirmed. He suggested an impartial public body to undertake this function. In the interim, farmers could only rely on the experience of other farmers. However, it was pointed out that variability in management practices would render such comparisons misleading. Dr. Pascual commented that we still do not know a great deal about fish and shrimp nutrition. Evaluation of feed based on crude protein levels alone is not an adequate measure of quality.
Mr. Chuah requested elaboration on the stability of semi-moist pellets. Mr. New replied that it may not be necessary to have high water stability. However, Mrs. Chou pointed out that high water stability is often demanded by the farmers when buying dry pellets.
To a comment by Mr. Ong, Mr. Jothy said that the current emphasis of the feed industry is in shrimp farming because the demand from the freshwater aquaculture sector is low. There are also more alternative feeds available. However, since freshwater aquaculture has a bright future, feeds for this sector may become important in the future. Mr. Kwan pointed out that this is already happening, albeit to a lesser extent than shrimp feeds.
Mr. Tang brought up the point that while feeds for different organisms are being developed, the energetics of their use should not be neglected. Mr. New agreed that emphasis should not be solely on compounded feed especially where it involves competition for feed ingredients from the livestock sector. This observation was shared by Dr. Pascual who said that while compounded feeds for milkfish are available, their use in the Philippines is still not economical.
3.2 The country review paper of Indonesia was presented by Mrs. Sariati Nizam.
In 1985, there were about 378 000 ha of brackishwater areas under culture producing about 305 000 metric tons of fish and shrimp. The government plans to increase aquaculture production through greater utilization of formulated feeds.
Various feedstuffs are available in the country but their use is limited by several factors such as competition with human consumption, inferior quality, limited quantity, the need for additional processing, etc. There are several brands of formulated fish and shrimp feeds available in the market, either produced locally or imported. There are about 13 feedmills producing fish and shrimp feed in Indonesia.
Problems and constraints related to formulated feeds were also discussed. These include the lack of knowledge on nutrient requirements of cultured species, limited availability of feedstuffs, quality control of imported ingredients and finished products, etc. Recommendations have been made to intensify research work on feed formulation, develop quality control programmes and to study the availability of feedstuffs in the country.
Discussion
To answer Mr. Jothy's question whether Indonesia could develop an indigenous feed industry without restricting imports, Ms. Sariati said that at the moment, the local feedmills could only fulfill 2 percent of the demand in the country. The government thus could impose a tax on imported finished feed.
Mr. Ung commented that the government did not protect local feedmillers since imported compounded feed was tax-free while feed ingredients were taxed. In response, Ms. Sariati said that the government reimburses the tax payable for raw materials imported for aquaculture feeds in order to help the local feedmilling industry.
3.3 The country review paper of Malaysia was presented by Mr. Ismail Abu Hassan.
According to Mr. Ismail there is potential for development of the feed industry in Malaysia. Almost all of the raw ingredients for feeds have to be imported for various reasons which include non-availability or irregular supply of local raw ingredients, poor quality of ingredients and price competitiveness. There is a need to increase both the output and quality of local raw materials. The government and private sectors should do more research to find alternatives to imported ingredients. He also briefly discussed the work and achievements of Fisheries Department's research in feed development.
Discussion
Mr. New commented that there may be a need to consider alternatives to marine protein in view of the high trash fish requirement of the aquaculture industry as presented in the paper.
Mr. Kwan mentioned that the organoleptic quality of fish would be altered by the nature of feed provided. His belief was that the use of moist feeds resulted in poor quality of fish flesh. However, Mr. New pointed out that the quality of the moist feed, not its moisture was the cause; after all the most moist diet of all is trash fish.
Dr. Pascual wanted to know if the feed formula developed by the Gelang Patah Fisheries Station was secret or not. In reply she was told it is still secret. However, farmers were encouraged to buy feed from the station.
3.4 The country review paper of the Philippines was presented by Mrs. Sofia B. Basa.
She reported that the main feed ingredients in the country include legumes, (especially Leucaena); other fodder crops such as (papaya, coffee, kangkong, camote, water hyacinth, sago palm); roots and tubers (arrow roots, sweet potato, cassava, taro and elephant yam); cereal by-products such as ricebran, soybean meal and maize; oil cakes such as copra cake and feeds of animal origin (snail meal, earthworm meal, toad meal, fish silage, feather meal, maggot meal, mussel meal). Live feeds available include Chlorella, Scenedesmus and Spirulina. Generally, most of these ingredients are readily available. However, trash fish supplies are difficult to obtain in view of competition with processed fish products for human consumption and livestock feeds. Fish meal is also imported to meet the needs of the livestock industry.
There are 11 feedmills producing both shrimp and fish feeds. Most of them were set up only recently. A list of these feed manufacturers is included in the paper.
Major problems facing the industry include:
Discussion
Mr. Ismail questioned the use of ricebran as a shrimp feed since it has poor digestibility and low protein. Dr. Pascual clarified that digestibility studies had not been carried out. However, studies made indicated that milkfish ingest ricebran and only partially digest them. The faeces then fertilize the pond. Ipil-ipil leaf meal is not now recommended for use as an aquaculture feed ingredient.
To a question by Mr. Tang, Ms. Basa clarified that fish silage is currently being looked into. However, Mr. Ismail said that the acidity of fish silage might affect pond water pH.
Dr. Pascual pointed that while earthworm meal was listed, it is not commercially available. Mrs. Sariati, however, added that flaked earthworm imported from Taiwan is used in their hatchery.
3.5 The country review paper for Singapore was presented by Mrs. Renee Chou.
The major aquaculture production systems found in the country together with the main species under culture and their feed requirement was presented. Currently, live food is still being used for shrimp and finfish larvae. However, the use of micro-particulate and encapsulated feeds needed to be verified from the nutritional and economic point of view. In the fish grow-out phase, pelleted feeds and minced trash fish are being used for shrimp. Finfish, except tilapia and carp, are fed on trash fish and semi-moist feeds.
The development of larval feed is towards the use of live feeds produced under controlled conditions or collected from the sea by special plankton collecting equipment. Supplementation by micro-feeds is also being looked into. In the nursery and grow-out phase, research and development have been directed towards producing nutritionally adequate, high quality and economically dry formulated feeds.
Discussion
A question was raised on the use of plankton collectors. Mrs. Chou said that the equipment is essentially a device to pump and concentrate plankton. The equipment is still under trial.
To answer a question on the formulae of moist pellets, Mrs. Chou said that while bulk ingredient formulation is variable, the Primary Production Department would like to stress on the need for micro-nutrient incorporation in such feeds.
Mr. Ismail claimed that the use of mussel meal is costly. Mrs. Chou said that the present quotation was based on estimate of locally produced mussel meal. She quoted a price of $4.50/kg dry form and reported $5–6 is usual for imported mussel meal. She felt that its use needed to be encouraged since the raw material is locally produced and available; it is also an excellent feed ingredient. Mr. New commented on the use of crushed whole mussels as a shrimp feed in China.
With regard to a question on spiny lobsters, Mrs. Chou said young spiny lobsters were collected from the wild and cultured in cages. She said the cost of production for banana shrimp (12 g body weight) in raceways is unknown because the system is still experimental and has yet to run on a commercial scale.
To answer Mr. Tang's question on the acceptability of moist and dry pellets, Mrs. Chou said that while seabass could switch easily from one diet form to another the weaning of grouper is more difficult.
A question was also raised on the FCR of seabass feed. She explained that for the dry pelleted feed, the FCR was 1.2:1 in experimental tanks but probably higher than 2:1 in production cages due to wastage.
Mr. Tang asked about the venture into culture of P. japonicus in Singapore. Mrs. Chou said that the trials are being done by a private company which is using 24 units of 1 000 m2 pond.
In response to Mr. Ong's question about the production from floating cages, she said that while the targeted production for intensive system such as those intended for verification is expected to be high, present production of floating farm cages is 30 tonnes/0.5 ha and this could be less than that of high-technology system.
To answer Mrs. Sariati's question on whether the fish produced is exported, Mrs. Chou said almost all are for local consumption.
3.6 The country review paper of Thailand was presented by Mrs. Nanthiya Unprasert.
There has been a trend toward semiintensive and intensive aquaculture systems in Thailand since 1986. As a result, a great demand for compound feeds has been created.
As far as feed ingredients for feed is concerned, Thailand is considered self-sufficient as about 90–95 percent of raw materials are available locally.
The feedstuffs for aquaculture are almost the same types as those used in livestock feeds but the feed formulae are very different.
Live or fresh natural feeds still play an important role in aquaculture especially in larval rearing.
The feedmilling industry has been one of the fastest growing economic activity in Thailand. The huge demand for shrimp and fish feed is a recent phenomenon.
One of the problems faced by Thailand is inadequate funds to carry out studies on aquatic animal nutrition requirements and on fish feed technology. The nutritional requirements and feed technologies developed in temperate countries are not entirely appropriate to the need of the developing countries for tropical species.
The paper recommended that study of nutritional requirements of the various tropical species for aquaculture use should be carried out.
Discussion
It was generally agreed that there was a shortage of trained manpower to carry out research on fish nutrition. The attention of participants was drawn to the fact that next year (1989) SEAFDEC would be organizing a 1.5–2 months training course on fish/shrimp nutrition. However, the Workshop felt that there is also a strong need for longer, senior training courses to develop technical manpower for fish and shrimp feeds technology and fish nutrition specialists.
Mr. Ismail requested that a list of feed manufacturers in Thailand be added to the country review paper of Thailand for the information of aquaculturists and scientists alike.
Mr. Ung asked about the mechanism for disseminating research findings of government institutions to the private sector. The Workshop agreed that research results should be made freely available to both manufacturers and farmers. A compilation of recent research results on shrimp and finfish feeds development was prepared by the Project Coordinator for the information of participants. This would be a useful reference material for feed research workers in the region.
3.7 The paper entitled “Formulated Feeds for Penaeus monodon” was presented by Dr. Felicitas Pascual.
The paper discussed the food and feeding habits of Penaeus monodon (Fabricius), present knowledge of nutrient requirements and the available formulations in the market including those developed at the SEAFDEC Aquaculture Department. Some data or the economics of feeding were also presented. Further research on the use of the indigenous feed ingredients and nutritional requirement studies were recommended to lower the cost of feeding and increase profits for farmers.
Discussion
Mr. New wondered why experimental diets contained 6–10 percent lipid content while most commercial diets in the region contained only 3.5 percent. Dr. Pascual replied that most feedmills did not have fat sprayers and, therefore, could not produce high lipid diets; this did not apply only to existing Taiwanese diets which were also low in fat. Mr. Ung agreed that the possibility of protein sparing through high lipid levels should be explored.
Mr. Kwan brought up the issue of blue prawns which he said could be associated with high aflatoxin levels in feed. Dr. Pascual clarified that studies had implied that Vitamin A, Astaxanthin and other carotenoids, phosphates as well as management practices had been implicated in the blue prawn syndrome. Mrs. Chou added that blue P. monodon had been detected in Singapore, but survival did not seem to be affected. No blue P. japonicus, however, had been detected.
Mrs. Umiyati asked what attractants were used. Dr. Pascual replied that mussel meat, shrimp head and squid meal were used.
Mr. Tang requested information on the level of BHT and moisture in the feed. Dr. Pascual clarified that 0.2 percent BHT and a moisture level of less than 10 percent prevailed in the finished feed. Studies indicate that the feed could be stored up to one month in plastic bags at room temperature without deterioration.
Mr. Ong asked if the SEAFDEC feed had been compared with other commercial feeds. Dr. Pascual replied that initial studies had been carried out and further studies are being planned. Diet 4 had been tested by three stations and FCR's of 1.5–2:1 had been obtained. Stocking density used in this study was 25 000/ha.
Mr. Che Utama requested if krill and squid meal had been evaluated. Dr. Pascual replied that only the use of shrimp head meal had been explored.
3.8 The paper on the Feedmilling Industry, the Assessment of Product Quality and the Economics of Shrimp Feeds was presented by Mr. Kenneth Chin from Gold Coin (Malaysia) Ltd.
The Malaysian feed industry has been heavily dependent on foreign supplies of raw materials. Hence, the cost of compound feed fluctuated with the availability of raw materials in the world market. Gold Coin, being an established feedmiller started experimenting with shrimp feeds in 1983. Taiwanese formulated feeds was then already dominating the market. Since the anticipated development of local shrimp industry in Malaysia did not fully materialize, Gold Coin has to look for export markets.
In the assessment of compound feeds, physical and nutritional characteristics are the two most important criteria. Physically, feed pellets must be of suitable size for each growing stage, digestible, have good water stability and be attractive, palatable and neutral in pH. In addition, the compound feed should be nutritionally balanced and have an attractive appearance.
Although commercial feeds are expensive because of the high cost of quality ingredients, they do offer several economic advantages. Gold Coin's commitment to the shrimp feed industry is evident by its research and development programmes, computerization and increase in manpower.
Discussion
Mr. Tang asked what minimum capacity of a feedmill plant would be economical and worthwhile. Mr. Chin said that it should be about 200–400 metric ton/month capacity.
A question was also raised regarding quality control in feedmills. Mr. Chin told the Workshop that the ingredients and finished feeds were both batch-analyzed. He also stressed that the feedmill policy is not to change feed formula often.
In response to a question about the amounts of feed exported and locally used per month, Mr. Chin said that about 100 metric tons are used in Malaysia, 50 metric tons are exported to Thailand and about 80 metric tons are exported to Indonesia.
A long discussion prevailed on Mr. Tang's suggestion that feedmillers should supply premixes to farmers for on-farm feed preparation. The Workshop concluded that such supply would depend on demand. Mr. New said that this was standard practice in Japanese cage farming.
3.9 The paper entitled “Status of Shrimp Feed Development at BADC Jepara, Indonesia” was presented by Mrs. Sri Umiyati Sumeru.
The paper outlined the development of larval, post-larval and grow-out diet for marine shrimp in an attempt to replace the relatively more expensive imported feeds. Artificial larval feeds based on local ingredients have been successfully developed. Tests on P. monodon indicated that the feed could be used as a supplement to live feeds without any adverse effect on survival and growth of the larvae. For post-larval feed, a brine shrimp flake had also been developed and proved to be effective. For grow-out, various formulations using different protein source have been attempted. Formulations using a combination of squid and soybean meal proved to be the best. The feed developed can be used to replace more expensive imported feeds.
Discussion
The participants were generally quite concerned about incorporation of antibiotics in formulated feeds both at the larval and grow-out stages. It was pointed out that such usage might lead to development of resistant strains of bacteria.
The need for proper experimental design in feeding experiments was again emphasized by Mr. New. The interpretation of experimental data was difficult without good experimental design.
3.10 The paper entitled “Effect of Various Protein Levels of Artificial Diets Mixed with Minced Fish Flesh Alone on Growth, Feed Conversion and Survival of Grouper (Epinephelus tauvina, Forskal)” was presented by Mrs. Thanom Pimoljinda.
A study had been conducted to determine the effect of mixing 45 percent, 50 percent and 55 percent protein artificial diets with minced fish flesh diet on the growth, feed conversion and survival of groupers. Fishes with initial size of 0.91 g in weight and 4.38 cm in length were fed on the experimental diets in 85 × 135 × 100 cm concrete tanks for 60 days. The result revealed that the growth rate of the fish fed with artificial diets plus minced fish flesh was significantly higher than the minced fish flesh alone. The survival rates of fish fed with 45 percent, 50 percent and 55 percent protein artificial diets plus minced fish flesh were 82.08 percent, 87.5 percent, 87.08 percent, respectively while minced fish flesh alone gave a survival rate 84.58 percent. Feed conversion rates were 2.83, 2.77, 2.68 and 3.95, respectively.
Discussion
Mrs. Chou commented that trials using fish flesh alone were carried out in Singapore but fish performance was observed to be poor. Whole fish, however, usually gave better growth results. She added that groupers could be trained to take a dry pellet and that a large stock was necessary to ensure even-size fish available at the end of weaning period. Mr. Kwan agreed that the use of fish flesh only could lead to calcium and phosphorus deficiency problems in fish.
Mr. New commented that the study was well executed, but the impact of the interesting results could be enhanced by using the data to calculate the cost of feeding. Using the data in this paper, he had calculated that the cost of feeding to produce 1 kg of grouper was B36 for the 45 percent diets, B37 for the 50 percent diet and B37 for the 55 percent diet and B55 for minced fish. This information is of vital interest to farmers.
Dr. Pascual described feeding trials of grouper in cages and ponds in SEAFDEC, 100 g fingerlings were stocked in 1 m2 cages at a rate of 1–5/cage and in 10 m2 ponds at 20/pond. They were fed trash fish twice a day and reached market size in about two months.
3.11 The paper on “Some Aspect of the Use and Manufacture of Formulated Fish Feeds” was presented by Mr. Kwan Foo Seong.
As production intensifies to enable more efficient utilization of the available resources, adequate supply of suitable quality feed is required. Presently, live food is still necessary for the early stages of cultured species. In the grow-out stage, natural feed, moist feed and dry pelleted feed can be used. Although moist feed offers the advantages of palatability, dry feed will be increasingly used in feeding fish due to their advantages of convenience, flexibility in manufacture and ready availability in the required quantity. With the existing established terrestrial animal feedmillers, the requirement for aquaculture feed can be fulfilled easily. The only bottleneck in the manufacture would be the need to grind the feed finely. There is no existing facility in Malaysia capable of producing extruded pellets, and Mr. Kwan questioned the need for that kind of feed.
The development of aquaculture feeds in Malaysia is hindered by the problems of a small and dispersed market, lack of precise data on the nutritional requirements of local species and the shortage of certain ingredients. The quality of feed can be evaluated chemically through proximate analysis and biologically through observation on growth and feed utilization. The presence of toxins such as aflatoxin has to be taken into consideration.
Discussion
There was considerable discussion about aflatoxin contamination of feed ingredients. The conclusion was that every ingredient is susceptible to aflatoxin contamination. This goes against the existing belief that only ingredients containing starch were affected by Aspergillus sp. Mr. Kwan also clarified that aflatoxin could not be denatured by heat but aluminium silicate compounds could be used for blocking absorption of the toxin. However, Dr. Hertrampf said that aluminium silicate compounds were non-selective and might also block other nutrients. It was suggested that anti-mould agents should be applied right after harvest.
Regarding the effect of the extrusion process on nutrients, participants felt that vitamins might be destroyed and protein partially denatured. However, digestability could be improved and vitamins added after extrusion. There were two schools of thought about the benefits of extrusion.
Mr. Chin stated earlier that the feed mash if kept in the conditioning chamber longer does not require binder; on the other hand, Mr. Kwan responded that it still needed a binder; this is standard practice in Taiwanese feeds.
The participants felt that floating feeds are not necessary for all species; the feeding techniques are more critical.
3.12 The next paper entitled “The Availability of Formulated Feeds, Their Manufacture and Feed Conversion Values Found in West Malaysia” was presented by Mr. S. Pathmasothy.
This paper indicated that in Malaysia, freshwater aquaculture is gaining popularity. At the moment there is a trend towards semi-intensive and intensive culture systems. As a result, the need for supplementary feed is also increasing. In large commercial farms formulated feeds are normally used.
Supplementary feeds used by small farmers are normally wet feeds which consisted of trash fish or chicken viscera comprising largely of intestines. The use of these feeds could give a conversion rate of 3:1 when fed to Pangasius sutchi. Copra cake mixed with other ingredients were also used.
Pellet feeds are not easily available to small-scale farmers. This is because feedmills generally would not take orders less than 1 or 2 tons.
Local feedmillers have the ability to produce high quality feeds. The majority of raw materials used are usually imported.
In the Fisheries Research Station at Batu Berendam, experiments on feed have also been carried out and the station also produced feed pellets of different sizes to cater to fish with different mouth sizes.
At present some feeds produced in the country have a feed conversion rate of two.
Farmers usually do not get good conversion rates because at the farm level, FCR is affected by many factors like water quality, the biomass of fish, the management of feeding (feeding regime, feeding frequency, feeding schedule, etc.):
Discussion
Mr. Liong Pit Chong commented that since most fishfarmers in Malaysia are doing semi-intensive culture, there is no immediate need for high quality complete feeds that are required in intensive culture. In addition, the price of most freshwater fishes are not high. In this connection, it was suggested that pellet feed should only be recommended for fish which fetch good prices like Pangasius sp. or red tilapia.
3.13 The paper entitled “Preliminary Study on the Effect of Formulated Feed Using Fermented Aquatic Weed Ingredients to the Growth Rate of Red Tilapia” was presented by Mrs. Sri Hartati Suprayitno and Djati Widagdo.
This paper covered feeding trials on red tilapia conducted in 600 wooden tanks. Twenty fishes of red tilapia were stocked per tank at the range of body weight of 4.29–5.25 g each. Four kinds of formulated feeds using fermented ingredients and various protein sources were compared with a commercial feed for 40-day feeding trials. The formulated feeds were processed into pellets and referred as Diets A, B, C, D and E. The fish were fed the diets ad libitum twice a day. The result showed that red tilapia fed with Diet A had a greater average weight gain than the others. There were significant (P> 0.05) differences in daily growth rate among different fermented diets, but fish fed with Diet A was not significantly different (P> 0.05) with fish fed with Diet E (commercial feed). There is an indication that Lemna sp. gave a better performance than Salvinia sp. Survival rate was 100 percent in all treatments.
Discussion
Mr. New commented that the diets should have been made iso-nitrogenous for meaningful comparisons to be carried out. Ms. Sri Hartati said that this was only a preliminary study and in the future, this would be carried out.
Mr. Tang and Mrs. Unprasert requested clarification of the fermentation of Salvinia and Lemna. Ms. Hartati clarified that the weeds were combined with yeast (Saccha-romyces sp.) and fermented for about seven days. The weeds were totally disintegrated by then. The yeast increases the crude protein content of the weeds. Fermentation also improved digestability while fresh Lemna will be eaten by tilapia, fresh Salvinia is not consumed by the fish; fermentation was a means of increasing acceptability.
Mr. Jothy brought up the possibility of using other weeds such as Pistia. Mrs. Hartati said that other aquatic weeds would also be looked into subsequently.
3.14 The paper on “Formulation of Feed for Cage Culture of Finfish in Taal Lake, Philippines” was presented by Mrs. Sofia S. Basa.
This paper was the result of an experiment done at Taal Lake, south of Manila. Three floating net cages each measuring 5 × 10 × 5 m were stocked with 1 800 Tilapia nilotica fingerlings. Cage one was fed with test diet which was formulated using local ingredients. Cage two was fed only with ricebran and cage three had no supplemental feed. Growth rate, feeding rate and feed conversion ratio were determined. The highest total weight gain was for the cage fed with test diet followed by the cage fed with ricebran and the control. The FCR was about 1:1 for the test diet and 0.61 for ricebran.
Discussion
Ms. Sariati asked the reason for the use of ipil-ipil leaves instead of cassava leaves and the form in which they were used. Ms. Basa replied that it was used because of abundant supply. It was used in meal form. Dr. Hertrampf asked whether ipil-ipil adversely affects the fish, Ms. Basa said this was not tested. Dr. Pascual, however, informed the Workshop that ipil-ipil leaves are not good for milkfish even at a low dietary inclusion rate. Dr. Hertrampf added that in terrestrial animal feeds, it is not used at more than 5 percent. Ms. Basa clarified that in her formulation, she only used 3 percent.
Various participants commented that it was difficult to draw clear conclusions from this paper since the initial weights of fish in each cage differed and there were no replicates. Further experimental trials will be carried out to obtain conclusive results. Cage fishfarmers are, however, using similar formulation which they make themselves. Data on results of their feeding need to be monitored.
3.15 The paper “Possibility of Using Rotifer Brachionus plicatilis as Food for Early Stage of Grouper Larvae, Epinephelus malabaricus” was presented by Mr. Mavit Assavaaree.
This paper outlined the larviculture of grouper using rotifer as the first larval feeds. It was observed that initially, only smaller rotifer could be ingested by the larvae due to smallness of the mouth. However, after the sixth day, rotifers of all sizes could be eaten. A survival rate of 33 to 55 percent could be achieved up to the 15th day of culture. Artemia nauplii could be used thereafter.
Discussion
In response to a question as to whether there was any change in the size distribution of the rotifer with time, the author replied that as half of the culture was harvested each day and the culture solution renewed, there was regeneration daily and hence, little variation of the size range. For three to five-day old larvae, there was a need to select smaller rotifers for feeding purposes after which rotifers of all sizes could be offered.
It was also pointed out that Chlorella-fed rotifers were generally smaller in size compared to Tetraselmis-fed rotifers and hence, are preferable. Yeast-fed rotifers, though small were apparently nutritionally unbalanced.
The initial stocking density of the larvae was reported to be 68/liter for the first 15 days reducing to 18/liter thereafter.
The experiment concerned the first 24 days only of culture because it was felt that only the initial 15 days were really critical. Once the larvae reached the size when Artemia nauplii could be ingested, the culture should not present much problem. It was also pointed out that besides rotifers, no other suitable feed had been found available in the quantities required.
3.16 The paper entitled “Dietary Protein Requirement of Early Grow-out Seabass (Lates calcarifer Bloch) and Some Observations on the Performance of Two Practical Formulated Feeds” by F.J. Wong and Renee Chou was presented by Mrs. Chou.
The optimal dietary protein requirement of seabass in the early grow-out phase (71–181 g) was determined to be 40–45 percent by the use of single protein reference diets containing protein derived entirely from fish meal. Trash fish was found to give significantly higher growth rates but no significant difference in terms of the feed conversion ratio. However, in fish fed with trash fish, protein retention was significantly poorer.
A second experiment was conducted to assess the performance of two practical dry formulations made from multiple protein source on seabass. The cheaper local formulation containing 43 percent and 12 percent fat performed better than the imported ration which had 50 percent protein and 16 percent fat. The local feed also had better protein utilization rates than the foreign feed or trash fish. In the trash fish, 87.2 percent of the digestible energy came from protein while 12.8 percent came from fat. In the test diets, 51.9–57.4 percent came from protein, 31.8–37.7 percent from fat and 10.3–12.1 percent from carbohydrates. Protein sparing in the test diets may, therefore, account for better protein retention in the fish fed with these diets. The use of trash fish alone is wasteful because it does not exploit the possibility of protein sparing by other energy sources.
Discussion
In response to an inquiry by Mr. Ung, Mrs. Chou clarified that the use of formulated feeds at commercial levels could be economically feasible comparing processing, storage and application costs as well as availability of both formulated feed and trash fish.
Mr. Ong asked with regard to the basis for selecting the protein levels tested. Mrs. Chou replied that seabass being a carnivorous fish was expected to have protein requirement in the high range.
Dr. Hertrampf felt that there was a limit to using lipid to spare protein since high lipid levels would lead to fatty fish. This would render fish unacceptable to consumers. Mrs. Chou clarified that this could be seen in the results with imported feed where the fish carcass had high fat levels than other diets.
To a query by Mr. Tang, Mrs. Chou clarified that actual measurement of digestible energy was not undertaken because it was not necessary at this point.
On a point by Mr. Tang that feeding to satiation may lead to overfeeding, Mrs. Chou clarified that the calculated feeding rates did not suggest this to be so.
Dr. Pascual asked if nursery or larval feeds were being developed. Mrs. Chou said that nursery feeds would be developed at a later stage. However, nutritional requirements of the larvae have not yet been worked on.
3.17 The paper on “Preliminary Observations on the Nutritional Effects of a Betaine/Amino Acid Mixture: Survival, Growth and Food Conversion of Juvenile Penaeus monodon Fed with FINNSTIM” by Mr. Ung Eng Huan and Junila, Matti was presented by Mr. Ung Eng Huan.
A commercially available betaine (trimethylglycine)/amino acid mixture was tested on juvenile Penaeus monodon housed in individual test-chambers so as to rule out death due to cannibalism in a 60-day trial. Three pelleted diets were used FINNSTIM mixture included at 0 percent, 1 percent and 2 percent, respectively. Growth rate, food conversion and survival was observed. The control gave a 99.45 percent weight gain while the 1 percent and 2 percent regimes gave weight gains of 116.3 percent and 119.3 percent, respectively. FCR's obtained were 3.74, 3.94 and 4.64 for the 2 percent, 1 percent and 0 percent inclusion diets, respectively. Survival rates of 88.8 percent, 72.5 percent and 70 percent were obtained for the 2 percent, 1 percent and 0 percent, respectively. Possible reasons explaining the enhanced survival rate at the 2 percent inclusion rate were given.
Discussion
Dr. Hertrampf pointed out that the experiment should have also included control diets containing choline and methionine since betaine is used to replace them in terrestrial diets. Mr. Ung explained that this will be examined in a future experiment and was purposely left out in this experiment as all were methyl donors.
Mr. Kwan informed the Workshop that one of the uses of choline chloride was to spare methionine in poultry feed because the price of choline chloride is 3–50 percent lower.
According to Dr. Hertrampf, choline can replace methionine only to a certain level in poultry; betaine cannot replace methionine or choline completely. Dr. Pascual postulated that the good result might have been due to the presence of amino acid contained in the FINNSTIM rather than the betaine since the amino acid profile in the basal feed could have been deficient. Mr. Ung suggested that other researchers countercheck the apparent efficacy shown in this study.
General discussion
In opening the discussion session, the Chairman suggested that the participants of the Workshop raise matters not brought up earlier during the presentation and discussion of technical papers.
Mrs. Delmendo pointed out that there was a general need to do nutritional research on the various species of fish being cultured. She also proposed that as suggested by Thailand, the methodology used for this research should be standardized. More trained manpower for nutritional research was required. The matter of cooperative research programme should also be considered.
Mr. New repeated the concern he expressed in his opening paper about the increasing requirements for trash fish, either for direct use or for the manufacture of fish meal for inclusion in aquaculture diets. Shortages of this commodity is likely to affect the prices of feed for all animals not just fish. Mr. New said that he was pleased to note that many of the speakers are paying attention to home-made feeds and to the needs of the small farmer, not just the large farms using pelleted feeds. Finally, he stressed that good experimental design was essential if research effort was not to be wasted. He suggested that researchers should seek peer review from those experts in this field within the region at the design stage of their respective research and not wait until the work was presented for publication.
Participants felt that nutritional studies should first concentrate on species which are already in commercial production.
A discussion on the alternatives to fish meal in aquaculture diets ensued. Though it could not completely replace fish meal, soybean meal, if adequately supplemented with synthetic amino acids is a possible substitute for reducing the demand for fish meal (and therefore, trash fish). Mrs. Delmendo pointed out the use of soybean meal in marine shrimps as reported by Dr. Addison Lawrence. Mr. New also mentioned the use of soybean meal in milkfish feeds. Others should be sought.
Participants felt that research into post-harvest handling of feed ingredients should be intensified to ensure a more consistent quality and supply of feedstuffs.
In addition, there is a need to improve the present utilization of feed ingredients. Applied research should be geared towards increasing the efficiency of utilization of the various ingredients, particularly trash fish (e.g. fish silage).
