Glossary



	abiotic Non-biological factors such as temperature, that form part of the environment of an organism. adenosine triphosphate (ATP) ATP is a nucleotide with 3 phosphate groups. When a phosphate is cut off from the ATP molecule (forming ADP: adenine diphosphate) a large amount of energy is released from the ATP molecule. This energy can be used by the cell to run some of its chemical reactions. amino acid Amino acids are small organic acids containing an amine (-NH₂) group and a carboxylic acid group (-COOH).They are the basic building blocks of proteins. Following digestion, free amino acids are absorbed from the intestine and distributed by the circulatory system to organs and tissues. There are 20 amino acids in total and in fish, 10 have been identified as essential dietary ingredients. ammonia A colourless strongly alkaline gas with a characteristic pungent smell. Chemical.formula: NH₃. anabolism Chemical reaction resulting in the production of new molecules and tissues. anoxia Oxygen deficiency in the blood cells or tissues of the body in such degree as to cause psychological and physiological disturbances. Anoxia may result from a scarcity of oxygen in the medium or from an inability of the body tissue to absorb oxygen under conditions of low ambient pressure. antibiotic Any of various substances (e.g. penicillin) produced by micro-organisms or made synthetically, that can inhibit or destroy susceptible micro-organisms. astaxanthin A member of the carotenoid family; a red pigment which is the predominant carotenoid of most crustacean species. bacterial infection Invasion of the body by pathogenic bacteria. benthic Pertaining to the bottom terrain of water bodies; describing the portion of the aquatic environment inhabited by organisms that live on or in the sediment. bile A bitter greenish-brown alkaline fluid which aids digestion; secreted by the liver and stored in the gall-bladder. bioenergetics The flow of energy through a biological system and the systems inherent system's requirements. biomass Any quantitative estimate of the total mass of organisms comprising all or part of a population or any other specified unit, or within a given area at a given time; measured as volume, mass (live, dead, dry or ash-free weight) or energy (joules, calories). biotic Relating to life or living things calcium (Ca) A malleable silvery-white netallic element of the alkaline earth group. An essential constituent of bones and teeth. Atomic No.: 20; Atomic weight.: 40.08. canthaxanthin A carotenoid pigment bloom (algal) A population burst of phytoplankton that remains within a defined part of the water column. cadmium (Cd) A malleable bluish-white metallic element that occurs in association with zinc ores. Used in electroplating and alloys. Symbol: Cd. Atomic number: 48. carbohydrate Any of a large group of organic compounds, including sugars and starch, that contain carbon, hydrogen and oxygen; a source of energy and component of various biological compounds including nucleic acids, mucous secretions and the chitin exoskeleton of crustacea. The presence of some carbohydrates may enhance the texture and palatibility of formulated feeds. carbonate A salt or ester of carbonic acid carnivore An organism that eats meat. Most carnivores are animals, but some fungi, plants, and protists may be too. catabolism Chemical rection resulting in the liberation of energy through final breakdown. catalyst A substance that increases the rate of a chemical reaction without itself undergoing any chemical change. chitin A polysaccharide that is the principal component of the exoskeleton of arthropods and of the bodies of fungi. cobalt (Co) A brittle hard silvery-white element that is a ferromagnetic metal: used in alloys. Atomic No.: 27; atomic weight.: 58.933 competition The simultaneous demand by two or more organisms or species for an essential common resource that is actually or potentially in limited supply (exploitation competition), or the detrimental interaction between two or more organisms or species seeking a common resource that is not limited (interference competition). consumer (ecology) An organism that feeds on another organism or existing organic matter, including herbivores, carnivores, parasites, saprophytic and heterotrophic organisms. Copper (Cu) A malleable reddish metallic element occurring as the free metal copper glance, and copper pyrites: used in alloys as brass and bronze. Symbol: Cu, Atomic number: 29. cyprinid A family of fresh water teleosts. There are about 1600 species, usually omnivorous or herbivorous. They have been traditionally cultivated in Asia. deamination The process by which proteins are utilized as an energy source when one amino acid is limiting or the protein component of the diet is in excess. degree day A unit used in the measurement of the duration of a life cycle or a particular growth phase of an organisim (e.g. egg development);calculated as the product of time and temperature average over a specific interval. digestion (1) In nutrition: the breakdown, in the alimentary tract, of complex organic substances into simpler substances so that they may be used in metabolisim. (2) In waste water treatment: catalytic activity, enzymatic activity and bacterial action in waste water treatment. dissolved oxygen The amount of oxygen, O₂, in solution under existing atmospheric pressure and temperature. dominance hierachy (feeding) A system of organisms which feed on each other arranged in a graded order. emulsification Making or forming into an emulsion. endocrine system Term applied to direct hormonal secretions and allied systems and processes. energy budget The dietary requirements of organisms, comprising a certain quantity of joules or calories per day to carry out certain living processes, e.g., growth, reproduction. enzyme Any of a group of complex proteins produced by living cells that act as catalysts in specific biochemical reactions. essential amino acids Amino acids which cannot be synthesised or stored in the body and must be ingested with food. There are 10 amino acids which have been identified as being essential in fish. extensive aquaculture The rearing of fish in semi-natural conditions: the production of a natural food supply within the system is the predominant factor in fish production. faeces Bodily waste matter discharged through the anus. fat soluble vitamin The vitamins, A,D and K which are soluble in fat (as opposed to water soluable). fatty acid Over 40 fatty acids are found in nature. Their physical, chemical and nutritional properties are determined by the number of carbon atoms in the molecule and the number and positioning of double bonds between carbon atoms. Fatty acids may be saturated, monounsaturated or polyunsaturated. feed attractant feed cannon A device that is used to deliver feed rapidly and in large quantities. feed performance The effectiveness of a feed in achieving its (present) targets. feed regime The regular set period for administering food. fishmeal A dehydrated and often defatted ground fish or fish waste produced in different grades and used as feed or less commonly as fertilizer. food additive Any substance added to a feed to improve it nutritionally, to prevent deterioration or to incorporate medications. Food Conversion Ratio (FCR) Efficiency of the stock at converting food into growth. furazolidone Furoxone, NF-180:3-(5 Nitrofurfurylic eneamino) 2-oxyadolidinone. A mitrofuran effective for control of Aeromonas salmonicida infections. furunculosis A systemic bacterial disease caused by Aeromonas salmoncida. All species and ages of fish are susceptible with the majority of outbreaks occurring in 1st year class fish. These outbreaks can occur at any time, are stress-mediated, and can be controlled by systemic antibacterials. Effective vaccines are now avaliable, but the best form of control is good husbandry practice. gall bladder The vessel storing bile after its secretion by the liver and before release into the intestine. gaping genotype The genetic constitution of an individual. gills The respiratory organs of many aquatic organisms. In fishes and crustaceans, these organs are also important in excretion, osmoregulation and mineral balance. In bivalvia, they play a major role in feeding glucose A six carbon sugar obtained from the hydrolysis of starches, sucrose, maltose, lactose and others; the major sugar found in the blood. glycerol A three carbon sugar alcohol, which is an important precursor of many lipids. herbivore An organism that feeds on plants or other autotrophic organisms.The term is used primarily to describe animals. hormones A chemical substance secreted in a ductless gland and discharged into the blood stream, affecting the functioning of another organ. hydrogen sulphide (H₂S) A strong-smelling soluble gas, H₂S, resulting from anaerobic decomposition; commonly found in the hypolimnion or bottom mud. Also can be released from the sedimented organic material (faeces and waste feed) that accumulates beneath fish cages or oyster trestles at sites restricted with regard to currents and depth. intensive aquaculture The rearing of fish within a holding unit, in which densities are limited by species tolerance, the ability to grow at raised stocking levels and the maintainance of environmental parameters, rather than the production of a natural food supply. iron (Pb) An essential micronutrient. A magnetic element with magnetic properties. lactose A disaccharide, especially abundant in milk, composed of glucose and galactose residues. latent heat capacity The energy as heat that is absorbed when a substance changes phase from solid to liquid (melting), or liquid to gas (vaporisation, evaporation). linoleic acid An essential fatty acid necessary for growth in animals. lipid Dietary lipids are the source of essential fatty acids in aquaculture feeds. They provide a rich source of energy and dietary phospholipids are vital as structural components of biomembranes. Lipids also serve as carriers for the absorption of other nutrients including fat-soluble vitamins A, D, E and K and natural or synthetic pigments. live diet Term used to describe the living organisms (e.g., rotifers, brine shrimps, etc) used to feed the larvae of certain finfish and shellfish, after hatching from the yolk sac, before being weaned on artificial diets. liver Organ responsible for many vital metabolic processes, such as the storage and filtration of assimilated products from the digestive tract. magnesium (Mg) An essential macro-nutrient a light silvery white metallic element (that tarnishes easily in air) and burns with an intense white flame to magnesium oxide. manganese (Mn) An essential micro-nutrient for plants/ a reddish-white hard brittle metallic element. maturation In embryology: the process of first meiotic cleavage and migration of the nucleus towards the animal pole, until germinal vesicle breakdown in post-vitellogenic eggs (hence, after completion of vitellogenesis). medication Treatment with drugs or remedies. metabolism The sum total of the chemical processes that occur in living organisms resulting in growth, production of energy, elimination of waste material etc. methane An odourless, colourless hydrocarbon gas produced either by natural or artificial anaerobic decomposition of organic material. mineral Inorganic salts required by aquatic organisms in moderate or trace quantities, for the correct functioning of an organism's physiological activities. Sufficient quantities of minerals are usually present in aquaculture feeds from the raw materials used. Compared to vitamins, minerals are cheap and stable and so addition of minerals to feeds does not contribute to higher feed costs moist feed A diet with about 30% moisture prepared from dry products, including a protein source and supplements. monitor A process consisting of regular investigations and the recordings of findings. monounsaturated fatty acid Fatty acid containing a single carboxyl group (COOH) and a straight unbranched carbon (C) chain with a single double bond. muscle An organ composed of muscle tissue. Muscle tissue is characterized by its ability to contract hence producing movement. Muscle is divided into two main groups: striated and smooth. Striated muscle is capable of voluntary contraction; all involuntary muscles except the heart are termed smooth muscle. myofibrils Contractile protein fibrils of muscle cells, composed of many myofilaments. myospeta nitrofuran Antimicrobial agents derived from furfural with a nitro group in the 5 position and various radicals substituted in the 2 position. They are active primarily against Gram negative bacteria, e.g. Nifurprazine (q.v.). nutrients A substance which provides nourishment; the term is often used to refer to dietary components. nutrition The sum of the processes in which an animal (or plant) takes in and utilizes food; the act or process of being nourished. omnivorous Literally, eats all or any kind of food; among protozoa, including many ciliates, such species appear to be satisfied in their feeding habitits by nutritive substances ranging from bacteria and algae to ciliates, tissues of multicellular organisms, and even detritus. Among crustaceans and fish, species feeding on a range of substances such as algae, plants, weeds, detritus, plankton and/or larger benthic and neritic organisms. optimal range Each species usually functions most efficiently over a limited part of its environmental gradient, known as its optimal range. osmoregulation The process by which organisms maintain a stable solute concentration. The maintenance of osmotic pressure on each side of a semipermeable membrane, i.e. osmotic balance. oxidise To undergo a chemical reaction with 0₂. eg. oxidation/reduction reactions. oxolinic acid A quinolone antibiotic that interferes with nucleic acid replication in bacteria. It is licensed for use in Japan and some European countries for the control of Aeromonas salmonicida and Yersinia ruckeri. pancreas Organ found in the primary region of the fish gut. The pancreas secretes digestive enzymes into the pyloric caecae, where digestion primarily takes place. parasite An animal (or plant) that lives in or on another (the host) from which it obtains nourishment. The host is sometimes adversely affected by the presence of the parasite. pelleted feed Feed in the shape of pellets made up of food particles in which all nutrient requirements for a cultivated species have been compounded, shaped through a die, either dry or frozen, in order to be fed to the animal. pepsin A proteolytic enzyme secreted by certain cells of the stomach wall. pepsinogen Inactive precursor of pepsin, secreted into the gastric lumen. phenotype A set of observable characteristics of an individual or group as determined by its genotype and environment. phosphates Any salt or ester of phosphoric acid, esp. used as a fertiliser. phosphorus (P) A non-metallic element occurring naturally in various phosphate rocks and existing in allotropic forms, esp. as a poisonous whitish waxy substance burning slowly at ordinary temperatures and so appearing luminous in the dark, and a reddish form used in matches, fertilisers, etc. photoperiod The period of daily illumination which an organism receives. physiology The science of the functions of living organisms and their parts. pigment 1. Colouring-matter used as paint or dye, usually as an insoluble suspension. 2. The natural colouring-matter of animal or plant tissue, e.g. chlorophyll, haemoglobin. piscine Of, or concerning, fish. plankton Microscopic organisms drifting or floating in the sea or fresh water. poikliothermic A cold-blooded organism; capable or regulating its body temperature by behavioural means, such as basking or burrowing. polysaccharide Any of a group of carbohydrates whose molecules consist of long chains of monosaccharides. polyunsaturated fatty acid (PUFA) Fatty acid containing a single carboxyl group (COOH) and a straight unbranched carbon (C) chain with more than one double bond. Potassium (K) An element essential for the growth and survival of living organisms. At the cellular level it is involved in maintaining intracellular ion balance and generating the membrane potential in all cells and in producing electrical signals in neurons. Also one of the major elements required for plant growth. prey An animal that is hunted or killed by another for food. producer (ecology) An autotrophic organisim, usually a photosynthetic green plant in an ecology which synthesizes organic matter from inorganic materials and is an early stage in a food chain ie, primary producer. progeny The immediate descendant or descendants of a person, animal etc; offspring. protease Any enzyme able to hydrolyse proteins and peptides by proteolysis. protein Any of a large group of nitrogenous compounds of high molecular weight. Essential ingredient in the diet of fish as a source of amino acids. pyloric caecae Blind-ended side branches of the first part of the fish intestine, at the end of the pyloric sphincter. They participate in the digestive processes as the principal site of protein digestion. respiration In living organisms, the process involving the release of energy and carbon dioxide from the oxidation of complex organic substances. R_maint Rate of nutrient intake required for daily maintenance. R_max The point of maximum voluntary food intake. saturated fatty acid Fatty acid containing a single carboxyl group (COOH) and a straight unbranched carbon (C) chain with no double bond. sediment Solid particulate material, both mineral and organic, that has settled from suspension in the water column (sedimentation) when hydrograpic conditions favour this phenomenon. semi-intensive aquaculture Generally used to describe a method of farming in which only part of the life cycle of the cultured organism is under managed control. Usually early rearing is controlled and subsequently the organism is released for ongrowing. shelf-life The amount of time for which a stored item of food etc. remains usable. shellfish Aquatic invertebrates possessing a shell or exoskeleton, usually molluscs and /or crustaceans. silo A pit or airtight structure in which green crops are pressed and kept for fodder, undergoing fermentation. smolt A characteristic stage in the life cycle of most salmonids: the juvenile salmonid at the time of physiological and physical pre-adaptation to the marine life. sodium (Na) A soft silver-white reactive metallic element, occurring naturally in soda, salt, etc., that is important in industry and is an essential element in living organisms. solubility The capacity of a substance to be dissolved. Specific Growth Rate (SGR) Growth rate of fish fed on a particular diet. starch An odourless tasteless polysaccharide occurring widely in plants and obtained chiefly from cereals and potatoes, forming an important constituent of the human diet. steroid Any of a group of organic compounds with a characteristic structure of four rings of carbon atoms, including many hormones, alkaloids, and vitamins. sucrose sugar, a disaccharide obtained from sugar cane, sugar beet, etc. sugar Sugars are carbon compounds with many alcohol groups (-OH) attached. They are burned or oxidized by animal cells to carbon dioxide and water, via a complex process known as glycolysis ("sugar-splitting"). Sugars polymerize to form oligosaccharides, macrolides (large rings) and branched and linear polymers. Since their empirical formulas are [C(H₂O)]n, sugars and their polymers are termed carbohydrates. sulphamerizine In pharmacology, a readily absorbed sulfonamide usually used in combination with other sulfonamide drugs to reduce renal toxicity. sulphonamide Antimicrobial compounds having the general formula RNO₂SH₂ and acting via competition with p-aminobenzoic acid in folic acid metabolism (i.e. sulfamerazine, sulfamethazine, sulfadimethoxine); cf. potentiated sulphonamides. sustainability The capacity to remove harvestable material over a period of time with non-apparent deleterious effects (on the system). synthesis The process or result of building up separate elements, into a connected whole. tetracycline Antibiotic produced by the actinomycete, streptomyces which inhibits the binding of +RNA to bacterial rebosomes which can be used against both gram-negative + gram-positive bacterial infections. tissue A group of similarly specialized cells that perform a common function, tissues make up the organs and other structures of living organisms. A tissue sample is a small representative piece of tissue which is removed for further study. tolerance limit The level beyond which an organism no longer has the capacity to endure something/ a state. toxin Any poisonous (toxic) substance tribrissen An antibacterial compound incorporated into feeds in order to combat bacterial infections and parasite problems. It is a combination of sulphadiagine and trimethropin, and reduces the side effects sometimes associated with other anti-bacterial compounds (eg kidney damage). triglyceride An ester formed when one molecule of glycerol combines with three similar, or different, fatty acids. trimethoprim Potentiated sulphonamides; refers to any anti-microbial agent comprising a specific member of the sulphonamide group in combination with a potentiator, usually trimethroprim. trypsin A proteolytic enzyme secreted by the pancreas and released into the intestine. urine Excretory fluid produced by the kidneys that plays an important role in the elimination of nitrogenous wastes and in the maintenance of hydro-mineral balance. vaccine A preparation of non-virulent disease organisms or immunogens which still retain the capacity to stimulate the production of antibodies or resistance to them; cf. antigen. vitamins A diverse group of organic compounds that are essential components of fish diets for normal growth, reproduction, and health. withdrawal period Zinc (Zn) An essential enzyme found in pancreatic juice of mammals (similar enzymes found in other animals and plants), formed from an inactive precurser, trypsinogen, by enzymatic cleavage in the small intestine by enteropoptidase. zymogen Functionally inactive precursor of certain enzymes, the active form being produced by specific cleavage of the polypeptide chain, (a proenzyme).