Glossary of Hatchery terms

Glossary of Hatchery Feed Terms - A - B

October 9, 2019


Additive — An ingredient or combination of ingredients added to the basic feed mix or parts thereof to fulfil a specific need.

Aflatoxins — A group of extremely heat-stable mycotoxins, produced by strains of Aspergillus flavus and A. parasiticus, which exhibit fluorescence on UV radiation. Aflatoxins are toxic to a wide range of eukaryotes.

Agglomeration — A process that produces a cluster of finely ground ingredients or microcapsules. For larval feed production, two methods are often used: (a) Microextrusion Marumerization (MEM): in this two-step process the ingredients are pressed through a die or screen with very small holes using either a cold extruder or a cooking extruder to produce long noodles; these are then broken into lengths approximately the same as the diameter with a marumerizer (b) PARA - Particle-Assisted Rotational Agglomeration: a lower pressure method which uses a marumerizer but not an extruder. It is capable of producing shaped feed particles of less than 400 um in diameter.

Alevin — The larval stage of fish from hatching to the end of dependence on endogenous yolk as a source of nutrition. This term is often restricted to salmonids and related fish before they emerge from the spawning gravel or incubation substrate, to begin swimming freely.

Alga (plural: algae) — Primitive chlorophyll-containing mainly aquatic eukaryotic organisms lacking true stems and roots and leaves.

Alginates — Industrial product derived from brown algae (seaweeds).

Amphihaline — Aquatic species, which passes periodically at well defined stages of its life cycle, from salt water to freshwater and vice versa.

Androgen  — (a) A fish that has only a male parent; all genes in an androgen come from the father (b) Anabolic steroid hormone that stimulates activity of accessory sex organs and sexual characteristics in males. They are often termed male sex hormones.

Antioxidant — A substance that chemically protects other compounds against oxidating thus enhancing stability and prolonging shelf-life; for example, vitamin E prevents oxidation and rancidity of fats.

Artemia — A small crustacean. At certain periods of the year, it produces cysts, metabolically inactive as long as they are kept dry, that float at the water surface of saline waterbodies; upon immersion in seawater, these cysts hydrate and the embryo resumes its development. The cysts can be easily used as a source of live food for early stages of fish and crustaceans.


Berry —  One of the eggs of a fish or a crustacean.

Binder — The adhesive component that holds   together the non-adhesive components of a compound mixture such as aquafeed.

Bioencapsulation — A technique whereby various substances, for example nutritional elements and prophylactics, are administered into living organisms, which can then be administered as feed to another animal.

Blastoderm — The foundation from which the  embryo will form on an egg. For practical purposes, the blastoderm is the same as the blastodisc or germinal disc of a fertilized egg.

Blastopore —  As the blastoderm grows over the egg, it finally leaves a circular opening or blastopore.

Blastula — A hollow ball of cells, one of the early stages of embryonic development.

Breaking stage —  Developmental stage of the brine shrimp cysts, when their shell (including the outer cuticular membrane) bursts and the embryo appears, surrounded by the hatching membrane.

Breeding color — Skin pigmentation developed during the spawning period.

Breeding cycle — A period between hatching and the first spawning of a given generation.

Brine shrimp — See Artemia

Brood — A group of young animals produced (spawned) at the same time.

Brood fish — Sexually mature fish, especially for propagation in fish farms.

Brooding — Care of the eggs during at least the early part of development. This can be undertaken either inside or outside the animal and can be undertaken by males in some animals.

Broodstock — Sexually mature specimens of both sexes kept for the purpose of controlled reproduction (independent of whether a first or subsequent generation is produced) as well as younger specimens destined to be used for the same purpose.