This book is intended to teach undergraduate students the essentials of aquaculture nutrition, feed formulation, and feeding management. It serves as a reference book for researchers in aquaculture, aquaculturists, fish farmers, and aquaculture nutritionists. For the basic understanding of the materials presented, it is essential that the students, teachers, and researchers have a good background in chemistry, fish biology, or fisheries. The book covers the subject areas of known nutrient requirements, effects of nutrient deficiencies on various aquatic species, nutrient sources, digestibility, and digestive physiology. Feed formulation, processing and storage, evaluation and quality control, feeding management, as well as the economics of feeding are included. Aspects on feeds and feeding related to the conservation of the aquatic environment are also dealt with. Each chapter of this book has common features such as an introduction, basic concepts, and a summary. Both the basic and practical aspects of fish nutrition are included to give the students and allow the readers who are unfamiliar with the topics a clear understanding and knowledge of these concepts. Study questions at the end of each chapter serve as a guide to summarize and impress on the students the salient points of the subject matter in each chapter. To easily comprehend the subject matter, there is an appendix containing the analytical methods and a glossary of technical terms. The users particularly the students are encouraged to broaden their knowledge by referring to the list of references and suggested readings at the end of each chapter.

This chapter teaches the reader to: differentiate the different feeding strategies in pond culture; learn feeding management methods such as stock sampling and record keeping, calculating daily feed ration, choosing appropriate feed size, and methods of applying feeds; understand the impact of feeding management on water quality and environment and on the cultured animal’s growth, survival, and feed conversion ratio; and describe the different feeding schemes used to culture fishes (milkfish, tilapia, rabbitfish, bighead carp, native catfish, sea bass, orange-spotted grouper, and mangrove red snapper; and crustaceans (tiger shrimp and mud crab). Other species for aquaculture stock enhancement (donkey’s ear abalone, seahorses, window-pane oyster) are also discussed.

This chapter discusses how to evaluate feedstuffs and feeds. The results of feed evaluation will be used to ensure the production of high quality feeds for fish, crustaceans, and shellfish.

The development of a feed that is both effective and economical for an aquaculture species in all its life stages is a continuous effort. Aquafeed development started when natural food sources in culture systems became inadequate and had to be supplemented with prepared feed. As fish stocking densities in culture increase, supplemental feeding is no longer sufficient. A complete feed that contains all the necessary nutrients in sufficient amounts to bring about good growth, survival, and reproduction is needed. Feed ingredients generally come from animal or plant sources and some are by-products of the food industry. There is no single feed ingredient or feedstuff that contains all the nutrients in adequate amounts. Thus, different feed ingredients are combined to make a feed that has the desired composition and nutrient levels. In combining various feed ingredients, it is important to know how much of each feed ingredient should be used to produce a cost-effective aquafeed. With the growth and expansion of aquaculture into a major industry, several fish species are being cultured; thus, the development of more efficient aquafeed formulations should continue. In developing cost-effective formulated diets, many important factors have to be considered. This chapter discusses these factors and the mathematical calculations in formulating a feed. It aims to enable students to formulate diets using purified and practical feed ingredients, and also to formulate effective supplemental and complete diets for aquaculture species.

This chapter provides basic information on the feeding habits and behavior, and physiology of fishes and crustaceans. The mechanisms that control the movement and digestion of food, methods of assessing digestibility of feed, factors affecting digestion and absorption of food nutrients, and feeding processes in fish are discussed. An understanding of the feeding habits, feeding mechanisms, and the digestion and absorption processes can help fish farmers and nutritionists maximize the use of feed. The rate at which fish digest their food is of primary importance in determining feeding rates, frequency, and ration size. Knowledge of the digestive physiology of fish is also necessary for an effective feed formulation and in choosing a proper feeding regime. This chapter aims to teach the reader: the feeding habits and behavior of fishes and crustaceans; the structural adaptation in the anatomy of the digestive tract; the various organs of the digestive systems of fishes and crustaceans and their functions; nutrient digestion and absorption by fishes and the fate of digested and undigested food; the factors that affect the rate of digestion and absorption; and the feeding process in fish.

This section describes the various lipid-soluble and water-soluble vitamins, their differences, physiological functions, and the symptoms of vitamin deficiencies in fish. It also shows a summary of nutritional deficiency signs and the requirements of various fish species for vitamins.

This section discusses the difference among the various forms of carbohydrate and their significance in fish nutrition; distinguish between utilization of carbohydrates by warmwater and coldwater fishes and know how dietary carbohydrates are made available to fish.

This section aims to teach the reader the ten essential amino acids required by fish and their chemical structures, distinguish between essential and non-essential amino acids; the fate of absorbed amino acids in fish; effects of deficiencies and excesses of dietary amino acids in fish diets; the procedure on how to determine the qualitative and quantitative amino acid requirements of fish; methods of evaluating protein quality; and how to determine protein requirements of some aquaculture species.

A survey was done in 1992 of 242 fish processors in Region III or Central Luzon: 57 in Bataan, 39 in Bulacan, 24 in Nueva Ecija, 45 in Pampanga, 41 in Tarlac, and 36 in Zambales. The fish processors were engaged in three major fish processing enterprises: fish smoking (52%), fish drying (17%), and fish fermentation (31%). The products were smoked fish ‘tinapa’, dried fish ‘daeng’, fish paste ‘bagoong’, rice-fish paste ‘buro’, and fish sauce ‘patis’. Most of the processors in Zambales, Bataan, and Bulacan produced bagoong; ‘buro’ was produced only in Pampanga. Of the processors, 105 were small-scale operators, most of them in Pampanga, Bataan, and Bulacan, who had average capital of P11,000, worked an average of 3 days a week, and processed an average of 5,000 kg of fish a year. The 90 medium-scale processors had average capital of P20,000 and handled between 5,000 and 20,000 kg of fish a year, 5 days a week. The 47 large-scale processors, mostly in Zambales, Bataan, and Tarlac, invested an average of P94,000, and handled more than 20,000 kg of fish a year, seven days a week. The 242 fish processors in Region III in 1992 employed 501 people, 47% of them family members. The total production of processed fish products was about 73,000 kg a month, including about 21,511 kg ‘tinapa’, 4,790 kg ‘daeng’, and 46,634 kg ‘bagoong’. Processors in Zambales fermented the most fish, about 23,000 kg/month, followed by those in Bulacan. Among those in fish smoking, Bataan processors produced the biggest volume of 5,900 kg/month. Fish drying was done only in Bataan and Bulacan, and Bataan processors produced about 2,800 kg/month. The fish processors in Region III sold their produce three ways: wholesale, retail, and contract buying. They followed a simple marketing plan, using outlets in nearby towns and cities, including Metro Manila. For six months of operation, the cost was lowest in fish smoking and highest in fish drying. Gross sales was also lowest in fish smoking, but highest in ‘bagoong’-making. Net profit was lowest in fish smoking and highest in ‘bagoong’-making. Return on investment was 38% in fish smoking, 41% in ‘bagoong’-making, but only 19% in fish drying. More than one-half of the processors earned incomes of P20,000–35,000 a month, one-fifth earned less, but one-fourth earned more. Fish processors in Region III in 1992 were on average 46 years old; nearly 80% were 26–55 years old and only two were younger than 26 years. There were more women than men in fish processing, particularly in Bataan, and about 93% were married. The respondents had formal education, but 60% did not go beyond elementary school. The respondents had considerable experience in fish processing, 60% of them having been in the business for 5–20 years, and 19% of them for even longer. Many reported household expenditures of P1,000–3,000 a month, but some also as high as P6,000–7,000 a month. The processors owned household appliances and furniture, and a few owned motorized boats. The Department of Agriculture provided extension services and credit to fish processors in Region III. Services included technical assistance, direct consultation, field visits, lectures, demonstrations, training, seminar, and preparation of feasibility study when availing of loans. Most fish processors in Bulacan considered extension services important, but most of those in Nueva Ecija were indifferent to extension services, apparently because they already had the needed knowledge and skills. In Pampanga, the older processors and those with greater investment considered extension services very important. In Zambales, processors with more experience required less extension services. In Bataan, gender, education level, investment, civil status, and income significantly influenced the processors’ assessment of the importance of extension services and the extent of their participation in the government’s extension program. Women considered it very important to avail of extension services, especially those who were married and those with little formal education.

The squid fishery in Carigara Bay used the following gears: hanging squid pots, squid jigs, drive-in net, and spear by slingshot. Hanging squid pot operations were concentrated in the municipal waters of Capoocan and Carigara and targeted Sepioteuthis lessoniana. During the one-week survey in Carigara Bay, 705 hanging squid pots with markers were found offshore of barangays Culasian, Pinamopoan, Cabul-an and Talarian, all in Capoocan town. Other operators in Carigara, Babatngon, Barugo, and San Miguel towns hung their squid pots from fish shelters (arong) offshore of Carigara and Capoocan towns. Test fishing operations were conducted in Carigara Bay from January to December 1992 using the hanging squid pot, squid jigs, and a squid cast net. A 16 hp motorized boat F/B Ellah Meh was used during the fishing operations. A total of 162 days test fishing with 15 hanging squid pots yielded 125.7 kg of the longfin squid Sepioteuthis 1essoniana. Sixty nights of fishing with the ordinary squid jig yielded 97 kg of Indian squid Photololigo duvaucelii. Two test fishing operations with the squid cast net yielded no squid at all. The S. lessoniana (75-500 g body weight) caught by pots were larger than the P. duvaucelii (7-270 g) caught by jigs.