Glossary of Hatchery terms

Glossary of Hatchery Feed Terms - M - P

October 9, 2019


Marumerizer — a sizing and shaping device that breaks extruded strands into small individual agglomerations and shapes them into spherical particles.

Microencapsulation — Liquids and particulate dietary components are enclosed within a coating, which helps prevent dissolving and leaching, but will release under specific environmental conditions.

Microextrusion Marumerization (MEM) — see Agglomeration

Microalgae — see Phytoplankton

Micro-ingredients — Vitamins, minerals, antibiotics, drugs, and other materials normally required in small amounts and measured in milligrams, micrograms or parts per million (ppm)

Mycotoxins — Toxins naturally produced by molds and fungi

Mysis — Pelagic larval stage of a crustacean intermediate between the protozoea (zoea) and postlarva stages.


Nauplius (pl. nauplii) — Earliest larval stage of a crustacean.


Particle-Assisted Rotational Agglomeration (PARA) — see Agglomeration

Pellet — Agglomerated feed formed by compacting and forcing it through die openings by a mechanical extrusion process.

Phytoplankton — Minute plants suspended in water with little or no capability of controlling their position in the water mass. The plant component of plankton. Frequently referred to as microalgae.

Plankton — Passively drifting or weakly swimming organisms, including many microscopic plants and animals.

Postlarva (pl. postlarvae) — Stage occurring after the larval stage, resembling the juvenile but still lacking certain characteristics. For  crustaceans: the stage following metamorphosis from larva (zoea) to juvenile. In penaeid shrimp, this is commonly counted in days after appearance of postlarval features, e.g. PL12 indicates a postlarva that has lived 12 days since its metamorphosis from the zoea stage of development.

Prebiotics — Non-digestible food ingredients that stimulate the growth and/or activity of bacteria in the digestive system that have favorable effects on the intestinal flora.
Probiotics — Live micro-organisms added to feed, which confer health benefits.

Protein efficiency ratio (PER) —  Ratio of live weight gain (in grams) over protein consumed (in grams). Production per unit of protein fed.

Protein utilization, (apparent) net (NPU)  — The amount of nitrogen retained by the animals over the total nitrogen consumed.

Protein, biological value of (BV) — Percent digested protein retained by the animal, expressed as the percentage of food nitrogen utilized for growth and body maintenance; this involves digestion, absorption, utilization and excretion of nitrogen-bearing compounds, especially proteins.
Protein, crude — The nitrogen content in a feed or animal or plant tissue, multiplied by a factor, which is generally 6.25.

Proteins, single-cell- (SCP) — type of natural food used in hatcheries made of individual cells (unicellular organisms), such as yeasts and microalgae fed to brine shrimp  nauplii.

Protozoan (pl. protozoans) —  A member of the phylum Protozoa, composed of mostly microscopic animals made up of a single cell or a group of more or less identical cells, reproducing by fission and living chiefly in water; includes many parasitic forms.
Protozoea (pl. protozoeae) — Larval stages between the nauplius and mysis in crustaceans; usually have seven pairs of appendages.

Proximate analysis —  (Analysis of) moisture, lipid, protein, fibre, ash and (by difference) carbohydrate content of any animal or plant product or mixed substance such as a feed.