From Big Medical Encyclopedia

FISHES (Pisces) — a superclass of the vertebrate poikilothermic animals living in an aqueous medium, breathing gills with pair extremities of not five-fingered type — chest and belly fins; skin is usually covered with scales. The superclass of fish is divided into 4 classes. From them 2 classes — Placodermi (armor-clad R.) and Acanthodii (chelyustnozhaberny R.) combine only fossil forms. The class Chondrichthyes (cartilaginous R.) along with fossil types of R. includes also the modern fishes belonging to subclasses of Elasmobranchii (lamellibranch, or akulovy, R.) and Holocephali (tselnogolovy, or himerovy, R.). The class Osteichthyes (bone R.) combines only modern types

of R. V to modern fauna contain (but to data of different researchers) from 20 to 22 thousand types of R.; in waters of the USSR contain apprx. 1400 species of fish.

The shape of a body, as a rule, bilateral and symmetric, is more often spindle-shaped, compressed from sides, happens taenioid (saber fish), serpentine (eel), flattened (a flounder, slopes) and even spherical (kuzovka). The sizes of a body fluctuate ranging from 1 — 2 cm to 20 m (whale sharks). Skeleton bone or cartilaginous (sharks and slopes). Chest and belly fins at nek-ry types are transformed to bodies of an attachment, copulation, a support or reduced. Unpaired back and proctal fins provide to fish vertical stability, and a tail stalk with a fin — the movement. Except organs of sight, hearing, sense of smell and touch R. have bodies of a sideline catching low-frequency fluctuations in water. Nek-rye R. possess hydrostatic body — the swimming bubble transformed at amphipneustic R. to lungs. There are R. possessing electric bodies (eels, slopes) using electric discharge for attack or protection.

Rubles inhabit sweet, sea and saltish waters, meet in thermal sources and in the reservoirs which are freezing through to the bottom, in reservoirs of highlands and caves. The coastal tropical zone of the western part of the Pacific Ocean is richest with R.'s types. Anchovies, flying fishes, sailing vessels, tunas, skumbriyevy, akulovy live in surface open oceanic waters (pelagiala) a herring. At depths the number of types of R. are less (shirokorota, the shining anchovies, dlinnokhvosta, the angler fish). For the Arctic and boreal sea waters fishes, and are characteristic of sweet waters — salmon podkamenshchikovy, kambalovy, be-ldyugovy, cod, the koryushko-Vyya.

R.'s food is diverse. They consume phyto - and zooplankton of thickness of water (plankton-eaters), organisms which are living at the bottom of (bentofaga) or the died-off organisms (detritophagous animals), eat overgrowings (perifitonofaga), hishchnichat. R.'s most breeds by an otkladka of eggs (calves) in water where there is a fertilization and the subsequent development, but there are viviparous types (sharks, slopes) possessing internal fertilization. Occur among R. hermaphroditism (see) and same-sex reproduction (gynogenesis).

River — the most important object of trade; meat, fat, caviar are eaten by people, cheap grades — on a forage an animal; fish meal is used as page - x. fertilizer. In the seas of the USSR the herring, a cod, a haddock, a pollock, a flounder, from R. through passage is traded (i.e. R.'s types living in the basic in the seas, but breeding in the rivers and which, on the contrary, are usually living in the rivers, but breeding in the seas) have the greatest value salmon and sturgeon; in internal reservoirs of the USSR cyprinid and okunevy Rubles are generally got.

Occur among R. poisonous and unsuitable in food, nek-ry of them become poisonous depending on objects of food or in a breeding season (see. Poisonous animals ). Nek-ry R.' pricks are very painful and are followed not only a local inflammation, but also the general symptoms of poisoning (spasms, a fever). Among R. there are hozyaystvenno useful: the gambusia and nek-ry other types eat larvae of malarial mosquitoes; herbivorous (cupid and a silver carp) are used for biomelioration — clarification of irrigation canals from thickets of vegetation.

Fish as foodstuff

Fish as foodstuff takes the important place in food of the population of many countries of the world and serves one of the main sources of protein and a number of mineral substances. In the USSR more than 130 views of the River have trade value.

For the food purposes P. it is got by operation of natural resources or cultivation of certain types of R. in fish farms. An edible part at R. makes 34 — 67% of mass of a carcass (muscles of a body, calves, milts, a liver of nek-ry types of R.).

Products from R. divide into groups: The river is fresh, salty, smoked and dried, canned food from R., culinary products from R., caviar, and from positions of dietology: on lean — contains less than 2% of fat (a cod, a pike perch, a pollock, a navaga), srednezhirny — 2 — 5% of fat (zherekh, a Siberian salmon, a flounder, a bream, a sazan), fat — more than 5% of fat (a sturgeon, a salmon, a grouper, a herring).

The chemical structure of R. and fish products hesitates in considerable limits. The amount of fat, and also its distribution in a body depends on biological features of a look, a season and R.'s age E.g., at sturgeon, nek-ry salmon and sigovy R. fat is distributed in intermuscular partitions; at seldy the ground mass of fat accumulates under skin, at som — in a tail and fins, at a cod and coal fish — in an abdominal cavity. High content iolinenasyshchenny fat to - t is peculiar to fat P. (e.g. at a jack mackerel their share makes apprx. 50%, at a tuna, a hake — St. 30%). However this feature does fats P. less resistant to oxidation in the course of storage.

Protein P. differs in high biological value (see the tab.).

R. and fish products contain vitamins D, E, thiamin, Riboflavinum, Folacinum, ascorbic to - that, etc. E.g., vitamin D in fabrics of a herring contains to 30 mkg / 100, Kets — to 16 mkg / 100, in granular caviar — to 8 mkg / 100.

Edible part P. contains also many mineral substances (To, Na, Mg, Sa, S, P, Fe, etc.). It is necessary to refer a variety of microelements in R. and rather high content to features of mineral composition nek-ry of them. So, the content of iodine at many sea types of R. reaches 30 — 65 mkg / 100, at cod — 135 — 310 mkg / 100, fresh-water R. have 4 — 5 mkg / 100. In R.'s muscles is about 3 times more With, than in meat. On the content of extractives P. does not concede to meat, and at a pike perch, a herring, it is more sardinella of purine connections, than in meat (at a pike perch of 60 mg / 100, a herring, sprats — to 100 mg / 100)

Features of structure of muscular tissue P. (lack of elastin and rather large amount of collagen) cause softer coagulation of proteins, promote deduction of water and preservation of a gentle consistence of dishes after heat treatment.

Dishes from fresh R., especially low-fat, cause less long, than meat, allocation of a gastric juice and juice of a pancreas; for digestion of fish proteins it is required to time how many and for milk protein approximately as much. The dietary value of R. as foodstuff is explained by it.

At a salting and production of smoked and dried products from R. muscular tissue is condensed, dehydrated, becomes impregnated with fat and develops a specific taste and a consistence. Though salty and dried R. are digested and acquired worse, than fresh R., however use of these products, and also caviar, in small amounts in the form of snack, increases appetite, stimulates release of digestive juices.

Large number of types of R., distinction in their chemical structure and nutrition value, use of various culinary and technological processing allow to use widely them in food of the healthy and sick person. From low-fat types of R. prepare specialized products for children of the first year of life. Dishes from R. are applied in to lay down. food at diseases of the digestive system, cardiovascular system, at disbolism, in food of the weakened patients and aged people.

Fresh R. belongs to perishable goods. R.'s damage is caused by the microbes coming from the habitat and also autolytic processes, to-rye in R.'s carcass go more intensively, than in carcasses of hematothermal animals.

The river which is especially caught in the contaminated reservoirs and incorrectly processed can become the reason of a number of bacterial and viral diseases — salmonellosis (see), typhoid (see), infectious hepatitis (see. viral hepatitis ), botulism (see), food toxicoinfections (see. Toxicoinfections food ).

Different types of R. can be sources of the helminthic invasions of the person caused by trematodes — opisthorchosis (see), clonorchosis (see), paragonimiasis (see); tape-worms — diphyllobotriasis (see), and also nek-ry nematodes (see. Nematodoses ). Prevention of helminthic invasions of the person is based on observance of rules of heat treatment, a salting, R.'s smoking and carrying out a dignity. - a gleam. works struck

with R. Nek-rye trade and edible R.' types contain the toxins dangerous to the person in areas of catch (see. Food poisonings , Poisonous animals ). Both separate bodies and fabrics, and R. in general can be poisonous. E.g., poisonous consider caviar of a marinka, the man with a big mustache, Ottoman, a gonad and a liver of skalozub, nek-ry seldy, sharks; virulence quite often changes depending on a season, the consumed forage and other factors. The poisonings known under the name of a sigvater are caused by the different types of R. (St. 400) living in coastal waters of the tropical seas and usually edible (a sea crucian, karanks, the goatfish, a reef perch, etc.), but sometimes their meat becomes poisonous. Satisfactory measures of prevention of this poisoning it is not developed.

Cases of poisoning with meat of a horse-mackerel, mackerel and others skumbroidny, and also tunas are known. In these R.' muscles there is a lot of histidine (see), to-ry under the influence of nek-ry microbes turns into histamine-like substance — thermostable toksinony Rapid cooling and R.'s processing prevent formation of toxin. The toxicity of a number of deep-water R. connected with features of composition of their fatty tissue is found.

Owing to biological features R.'s organism is capable to concentrate mercury, arsenic and other toxic agents. Therefore the content of mercury in R. is normalized in a number of the countries (including in the USSR) and shall not exceed 0,1 — 0,5 mg/kg, and for tunas a little bigger quantity is allowed (to 1 mg/kg).

In order to avoid damage fresh-caught R. shall be cooled, preserved immediately in any way or go for cutting. Living R. is transported by special transport (live-fish autocontainers, tanks, cars) in the conditions providing its normal physiological state and excluding bruises. Special attention is paid on temperature and a dignity. quality of water; in transit living R. in shops is offered to add to water anesthetics (e.g., cinchona of ice floes) that leads to oppression of mobility and decrease in oxygen consumption; after change in more spacious aquariums anesthetics are completely removed from an organism of River.

Transportation, storage and sale is fresher and is carried out by the cooled R. (temperature in the thickness of meat from — 1 ° to 4-5 °) according to the existing rules and instructions. At the same time gigabyte. requirements to storage, transportation and sale of different fish products are various and depend on features of a type of a product. So, culinary products from fresh R. and smoke-cured R. belong to perishable goods; their storage at a temperature close to 0 ° shall not exceed 3 days.

Salty R. contains from 6 to 14% and above sodium chloride. At such concentration of salt reproduction of the microbes causing food toxicoinfections is suppressed. However salty R.'s damage can happen at the expense of galofilny bacteria and mushrooms (Serratia salinaria, childbirth of Oospora, Sporendonema); at 8 ° — 10 ° and below their development practically stops. The preserving R. agents of cold smoking are salt and antiseptic substances of smoke, however nek-ry microbes and a mold (e.g., Penicillium) are steady against their action and can cause damage of the smoked River. Salty, smoked and dried R. at a temperature from +8 ° to +10 ° remains several months. The salty, smoked, and also dried R.'s damage connected with oxidation of fats accelerates under the influence of oxygen of air and light.

Caviar P. is a product, unstable to bacterial and oxidizing damage. Extraction and processing of caviar are made almost in aseptic conditions. For conservation of granular caviar of sturgeon and salmon R. use salt (3 — 6%), hexamethylenetetramine (1 g/kg), the benzoic to - that (to 2 g/kg), sorbic to - that (to 1 g/kg); granular caviar of sturgeon can be exposed pasteurizations (see). Caviar of other types of R. is preserved by salt (6 — 14%). Caviar with addition of preservatives is usually stored to 10 months.

Control for a dignity. conditions of production and quality of fish products carry out by bodies and institutions G osudarstvenny a dignity. supervision, and also other ministries and departments.

Methods of a research of foodstuff from R. are ordered by state standard specifications and include chemical (definition of sodium chloride, preservatives, tin and other metals, ammonia etc.), physical (definition of moisture), bacteriological and parasitological methods.


Bibliography: Berg L. S. Fishes of sweet waters of the USSR and the adjacent countries, p.1 — 3, M. — L., 1948 — 1949; To the Breeze. Pollution of coastal waters microbes, viruses and parasites and its value from the point of view of public health care, Bulletin WHO, t. 38, No. 1, page 76, 1968; Hygiene of products from fish, mollusks and Crustacea, the Report of committee of WHO, Is gray. tekhn. dokl. No. 550, M., 1975; Levinton Zh. B. Perspectives of use of some species of fish in food of the population, in book: Diet, pitas., under the editorship of P. N. Maystruk, century 15, page 32, Kiev, 1980; Lindberg G. U. Determinant and characteristic of families of fishes of world fauna, L., 1971; Nikitin B. P. Fish products, M., 1968, bibliogr.; Nikolsky G. V. Private ichthyology, M., 1971; Pigulevskiys. B. Poisonous animals, Toxicology of vertebrata, L., 1966; Holsted B. U. Dangerous marine animals, the lane with English, L., 1970, bibliogr.; Microbial safety of fishery products, ed. by of Page O. Chichester a. H. D. Graham, N. Y., 1973.

BB. E. Lapin; A. H. Hares (pitas.).