Feeds for Small-scale Aquaculture: Recent submissions

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    • The effect of different levels of vitamins premix in the diet of African catfish (Clarias gariepinus) fingerlings 

      Monje, Priscilla; Dizon, M. P.; Divina, C. C. (Aquaculture Department, Southeast Asian Fisheries Development Center, 1996)
      The present study was conducted to determine the growth and survival of African catfish (Clarias gariepinus) fingerlings fed diets with various levels of vitamin premix. The fingerlings (mean weight, 1.55 to 2.12 g) were stocked in circular concrete tanks measuring 1.5 m x 17 cm at a density of 50 fish/tank. Fish were fed 42% protein diets containing of 0, 1,2 and 3% vitamin premix (commercially blended). The fingerlings were fed at a rate of 10 % of the total body weight. Feeding was done three times daily at 0800, 1200, and 1600h. Feeding rates were adjusted based on the average weight of the fish every after sampling period. The fish were given the experimental diets for a period of 8 weeks. Results showed no significant differences in the weight gain and survival rate of the catfish. Water quality parameters such as dissolved oxygen, pH and temperature were not affected by the addition of vitamin premix at the level of up to 3 percent in the diet of African catfish fingerlings.

    • Future considerations in fish nutrition research 

      Lim, Chhorn (Aquaculture Department, Southeast Asian Fisheries Development Center, 1996)
      Considerable progress has been made In the field of fish nutrition during the past two decades. Nutritional data for some species such as trout, salmon, channel catfish, and common carp are well established and efficient feeds have been developed. However, nutrition of fish species commercially Important In the Southeast Asian region is still in its infancy and much of the existing Information needs further verification. Basic requirements for some of the 5 major nutrient classes and energy have been determined. However, knowledge of larval and broodstock nutrition is limited. The role of nutrition in immune function and disease resistance should be investigated. Nutritional value and nutrient bioavailability of local feedstuffs as well as methods for improving the nutritional quality of inferior feedstuffs should be given priority. The potential benefits of additives, and harmful effects of toxicants and anti-nutritional factors need to be assessed. The effects of the diet on product quality are becoming increasingly important, but work on feed processing technology in relation to the physical and nutritional quality of feeds is lacking. Emphasis must also be given to the improvement of feed performance and feeding strategies for various life stages under different production systems and management practices in order to reduce production costs and minimize the negative impact of feeds on the environment.

    • Review of SEAFDEC/AQD fish nutrition and feed development research 

      Millamena, Oseni M. (Aquaculture Department, Southeast Asian Fisheries Development Center, 1996)
      Research on fish nutrition and feed development at SEAFDEC Aquaculture Department has focused on three major areas: nutrient requirements and their interrelationships, digestive enzymes and digestibility, and practical feed development for important species such as milkfish (Chanos chanos Forsskal), sea bass (Lates calcarifer), Nile tilapia (Oreochromis niloticus), bighead carp (Aristichthys nobilis), and tiger shrimp (Penaeus monodon). Early studies on the nutrient requirements were mainly on protein, lipid and carbohydrate. Studies on essential amino acids and fatty acids, and optimum proteln:energy ratio in the diets for cultured species were conducted later. Likewise, requirements for other essential nutrients in shrimps, like phospholipid and cholesterol, were studied. Dietary calcium and phosphorus required to prevent soft-shelled shrimps were determined. Requirements for water-soluble vitamins and bioavailability of stable forms of vitamin C were evaluated. Little is known of the vitamin and mineral requirements.The major digestive enzymes in milkfish have been studied. The apparent digestibility of common feedstuffs were determined in vivo and in vitro for milkfish and tiger shrimp, and presently, for sea bass. Development of cost-effective practical feed continues to be a major research undertaking at SEAFDEC/AQD. Diet refinement emphasizes on use of inexpensive and indigenous materials in diet formulations. The feasibility of using legumes, leaf meals, and agricultural by-products and wastes as feed components has been demonstrated. Feed and feedstuff quality control and proper processing techniques were found to improve the nutritional value of low-grade raw materials. Improved feeding techniques and practices have been pursued to minimize feeding costs. Studies on the effect of feeds on the environment are being initiated. Economically feasible grow-out diets for semi-intensive culture of milkfish, Nile tilapia, and tiger shrimp, and diets for broodstock and larvae of these species have been developed.