Aquaculture is gaining more and more importance as a

means to augment finfish and shellfish production in both the developed and developing countries of the world, to partially meet the growing demand for fish and shellfish protein. It has been predicated by TAG (1973) that by the year 2000, aquaculture could produce at least 50 million tons of animal protein, if certain research and development measures are undertaken, as against the production of 6 million tons of fish and shellfish through culture in 1975 (Pillay, 1976)

Paulraj, R

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• i . IB^^mmf^-mmmmmmifm^mm'im Proceedings of the Summer Institute in Recent Advances in Finfish and Shellfish Nutrition 11 TO 30 MAY 1987 CENTRAL MARINE FISHERIES RESEARCH INSTITUTE Dr. SALIM ALI ROAD COCHIN-682 031 i l^ehm'c^ f*c|i(k.vi SUMMER INSTITUTE IN RECENT ADVANCES IN FINFISH AND SHELLFISH NUTRITION 1 1 - 3 0 May, 1987 NUTRITIC^I 33^;AQUACULTURE - AN OVERVIEW R. PAUL RAJ Nutrition Section, Central Marine Fisheries Research Institute, Cochin-682 031. Aquaculture is gaining more and more importance as a means to augment finfish and shellfish production in both the developed and developing countries of the world, to partially meet the growing demand for fish and shellfish protein. It has been predicated by TAG (1973) that by the year 2000, aquaculture could produce at least 50 million tons of animal protein, if certain research and development.measures.are undertaken, as against the production of 6 million tons of fish and shellfish through culture in 1975 (Pillay, 1976). In India, traditionally an extensive type of aqua-culture was piracticed by the farmers in the states of Kerala, West Bengali Orissa and some of the North-Eastern States. Production realised from this system of aquaculture was extremely low, being less than 1 ton/ha/yr. These tradi-tional practices being largely governed by local conditions and needs, the farmers seldom felt the need to intensify operations. Low-density culture with minimum inputs and low production per unit area has often been more economical than intensive farming, involving the rearing of dense popu-lations and heavy inputs (Pillay, 1976). Recent researches have amply proved that by adopting scientific culture procedures and efficient management • • 2 • • practices substantial increase in production could be obtained especially firpm finfish and prawn culture systems. Production rate as high as 10 tons/ha has been achieved in static earthen freshwater carp culture ponds in India through optimum stocking, fertilization and supplementary feeding. Peed is often considered as the major operational input in semi-intensive and intensive finfish and prawn culture systems. Feed costs often exceed 50% of the opera-tional costs in intensive culture operations. In view of this practical feeds both supplemental and conplete should be carefully fornulated, and judiciously supplied considering the specific nutritional needs of cultivated species and the intensity of culture operation. In Semi-intensive systems, the supply of supplanentary feeds can be regulated judi-ciously keeping in view the quality and quantity of the natural food produced in the pond. Natural food production can be increased through systematic and judicious admini-stration of organic and inorganic fertilizers. Thu« in this system, the exogenous food supply need to provide only nutrients which may be deficient in the natural food, so that the feeds are effectively utilized. Anrang the three major groups of cultivable aquatic organisms, the bivalve molluscs are mainly cultured in open water bodies. Thus the production of most species of molluscs mainly depend upon the availability of plenty of preferred natural food in the system. In contrast to bivalve molluscs, finfish and crustaceans are cultured in ponds, raceways, cages, pens and recirculated systems. In these systems, in order to achieve optimum production, provision of compounded feeds, either supplementary or complete, forms are essential requisite. • • 3 • • Besides the need for feeds for grow-out systems, feeds are also required for hatcheries and nurseries to produce healthy stocking material. The larvae of most of the finfish, crustaceans and bivalve molluscs require micro-patticulate diets during the early larval phase. In most casei live-food particularly phytoplanktcn are being fed. While the bivalve molluscs continue to have preference for microparticulate diets, the advanced larvae of crustaceans and the fry of finfish efficiently ingest zooplankton and fornuilated feeds. In Table 1 the important basic food types ingested by the larvae are presented. Live-food production necessitates additional infrastructure, manpower and opera-tional inputs, thereljy the cost of production of stocking material is greatly enhanced. Table 1: Potential sources of diets for larvae Viable Non-viable a) bacteria b) motile gametes, spores c) yeast d) phytoplanktcn -- diatcans - unicellular algae e) zooplankton a) detritus b) organic aggregates c) artificial formulations - micsroparticulate diets - microencapsulated diets d) tissue suspensions Recent developmaits in feed technology reveal that microencapsulated diets can be fed to larvae in hatcheries. Encapsulation is a process by which liquid or particulate materials are enclosed within a specially designed artificial membrane or wall made of natural polymers, as gelatin, gums, waxes or the synthetic polymers of ethyl cellulose or polyvinyl alcohol, TSie type of capsule required depends on the mode of feeding; for instance, molluscs ingests the food whole and nuist be provided with a capsule whose walls are stable to sea water but readily soluble in the digestive tract of the animal by the action of digestive juices. Thus for the larvae, development of nutritionally adequate mlcro-particulate or microencapsulated diets with appropriate size, texture, taste etc. is most iitportant. Fonwalated feeds should contain adequate levels of nutrients to meet the physiological needs of the organisms, such as to supply energy, to build and maintain the cells and tissues, and regulate body processes. According to Halver (1976) any balanced formula for fish diets must include an energy source plus sufficient indispensable amino acids, essential fatty acids* specific vitamins and minerals to sustain life and promote growth. Studies with crustaceans shew that in addition to the nutrients listed above, a dietary source of sterol and phospholipids are essential for norrtal growth and metamorphosis (Kanazawa, 1984). All the essential nutrients (Table 2) should be incorporated in adequate levels and in optimum proportions in compounded diets. Any imbalance of these nutrients would affect the efficacy of conversion of food by the animals. Quantitative requiranents of specific nutrients vary with species, size, physiological condition, temperature, stress, nutrient balance of the diet and environ-mental factors, thus economical rations nwst be programmed accordingly. • « 3 • • After determining the nutritional requirements of the species, it is essential to identify feed ingredients which would provide the essential nutrients for formulating practi-cal diets. Thus nutritional and ingredient standards are defined. Finally the diets are prepared as dry pellets, moist-pellets, flakes, pastes, microparticulates, micro-capsules etc. keeping in view the specific preferences of various size groups and physiological stages of the species. Binders, antioxidants, mold inhibitors, anabolic agents, colouring and flavouring agents can be added as additives depending upon specific needs. In the process of feeding aquatic animals, a general understanding of the type,of digestive system found in the animal is essential (Mac Grath, 1975). Information about the ability of the animal to chew or break feed particles into smaller units, thus increasing the surface area of feed particles for greater ease of ingestion and digestion, and about type of digestive tract the animal has and its histo-logy are required. In addition, digestion and absorption efficiency are required. These informations would help in evolving suitable diet forms for the species and stage concerned. Based on the informations on nutritional requirements of the species and availability of nutrients in various feed-stuffs and nutritional environmental interactions diets can be formulate keeping the cost of the finished product igi view. For achieving maximum production the feeding strate-gies employed ^re very important. Feeding strategies are evolved based on the size and physiological stages of animals, water quality, water ten^erature, feeding habits of the animal, dietary form, behaviour of the animals etc. Thus nutrition and feed formulation research involves a number of stages, which are summarized in Fig. 1, • • o • • Table 2; Essential dietary nutrients for finfish and Shellfish Energy nutrients? Proteins, lipids, carbohydrates • Non-energy nutrientsi Vitamins, minerals Essential amino acids 'J • • "•' 1. Valine 2. Isoleueine 3. Threonine 4. Tryptophan -5y Arginine 6. Lysine 7• Leucine 8* 'Phenylalanine Tyrosine 1 9, Methionine Cystine llO. Histidine Vitamins . • ( • 118. Thiamine s jl9. Riboflavin S20. Pyridoxine J21. Choline j22'. Niacin \23. Pantothenic acid j24* Inosital J25, Biotin 26* Folic acid 27. Cyanocobalamin 28. Ascorbic acid 29. Vitamin A 30. Vitamin D 31. Vitamin E 132. Vitamin K Essential fatty acids 11. Linolenic acid (18;2w6) 12. Linolenic acid (18:3w3) 13. Eicosapentaenoic acid (20J5W3) 14. Docosahexaenoic acid (22!6w3) Sterol 15. Cholesterol Phospholipids 16. Phosphotidyl choline 17. Phosphotidyl ethanolamie Minerals 33. Calcium 34. Phosphorous 35. Coppeir 36. Magnesium. 37. Zinc 38. Cobalt 39. iron 40. Iodine 41 • Manganese 42. selenium 43. Molybdenum I • • • V • • P i g . 1 • NUTRITIONAL ElESEayiCH BASIC Nutritional requironents (size, stage, pl^siological, condition) Digestive syston and digestion Metabolism of nutrients Nitrogen and energy balance Excretion Metabolic rates Nutrition and Environment interaction Inter-relationships between nutrients Influence of nutrients on body composition APPLIED Ingredients -potential nutritive value composition-antinutritional factors biol9itical value Digestibility of nutrients in diets Feeding rates and factors influaK!ing it Diet growth Diet form Additives: determining safe levels of antioxi-dants, mold inhibitors, anabolic agents ^  binding agents etc. Nutritional standard Ingredient standard lieast-cost formulation Process Finishes Microparticulate Microcapsules "* Flakes Meals feeds Pellets ^ hard. - soft Process standards Storage - shell-life REFERia^ CES Halver, 1976. The Nutj^itional requirements of cultivated warrnwater and coldwater species. FAQ Technical Conference on Aquaculture^ Kyoto. Japan, 26 May to 2 June, 1976. FIR/AQ/Conf. 76/R, 131. Kanazawa, A. 1984. Nutrition of penaeid prawns and shrinks* Proc> of the First International Conference on the culture of penaeid prawns/shriraps. Illoilo City* Philippines, 1984, Mac drath, W.S. Jr« 1975. The role of feed Industry in developing formulated feeds for aquaculture* Proc* First international Conference on Aquaculture Nutrition. Delaware. K.S* Price, W.N, shaw and K.s. Danberg (eds), p. 119-123. Pillay, T.V.R. 1976. The State of Aquaculture 1975. FAO Technical Conference on Aquaculture, Kyoto, Japan, 26 May - 2 June 1976. FIR/AQ/Conf./76/R.36 Ravenna Ukeles, 1975. Views on bivalve larval nutrition. In Proc. First International Conference on Aqua-culture Nutrition, October 1975. Delaware, K.s. Price, W.N. Shaw and K.s. Danberg (eds.), p. 127-167, TAG Secretariat, 1973. Report of the Tac working Group on Aquaculture consultative group on international Agricultural Research, Technical Advisory Coninittee. Seventh Meeting^- Rome. 4-8 February 1973. Rome, FAO, DDDR: lAR 73 (75) NOV. 1973: 25 p. 

Nutrition in  aquaculture - An overview

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Nutrition in aquaculture - An overview

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