1.   Types of feed microscopy Microscopy

A flexible, fast and inexpensive feed quality control technique.

It is the ideal complement for the classical chemical analyses (Weende, van Soest,), and provides faster general information on ingredient quality. It is especially useful for the

identification of tainting or adulterating materials, or for quantitative determinations when specific physical or chemical methods do not exist. It can become a part of any quality control system, because the required equipment is simple and affordable for any feed manufacturer.

Feed Microscopy can also be applied to any segment of the feed manufacturing process. It helps to solve potential operational problems, and can be especially important during the mixing stage. Mix quality (formula compliance), and the presence or absence of some micro-ingredients (minerals, vitamins) can be established by the observation of specific microtests. The microscopic analysis of mixtures can constitute an important probe of the manufacturing process’ adequacy, especially when it includes further processing that may alter the initial characteristics of the ingredients. An example of this is starch gelling due to extrusion or expansion. On the same token, charred particles, fragments of bone, metal, rubber or insects can be identified faster than with any other physical or chemical procedure.

There are two main groups of feed microscopy Qualitative microscopy

Quantitative microscopy

2.   Qualitative microscopy

Qualitative microscopy aims at the identification of ingredients and extraneous materials, alone or mixed, through recognising their external appearance (stereo microscopy) or their cell features (compound microscopy

• Identification of feed ingredients & extraneous materials alone or mixed, through recognizing their
• external appearance (stereo microscopy)

• OR

• Cell features (compound microscope)

• Identifies and evaluates feed ingredients and foreign particles.

Physical characters & structure

• (smell, taste, touch, sound, homogeneity, size, shape)

•      Chemical test

• Analyses the feed for proximate principle

• (Crude fiber, ash, fat, CP)

3.   Quantitative microscopy

Quantitative microscopy includes additional measurements of relative proportion of ingredients, and tainting and/or adulterating materials on complete feed.

• Relative ingredients

• Tainting

• Adulterating materials on complete feed

• Includes additional measurements of relative proportion of ingredients, and tainting and adulterating materials on complete feed.

TAINT

• Unpleasant odors or flavors imparted to food through external sources ADULTRANTS

A substance added to a product but not listed as an ingredient,

Microscope use in feed microscopy

• Both types can be performed using stereo microscopes and compound microscopes

• In practical terms, the stereo microscope is more widely used,

• At 10x and 20x,

•      The basic equipment for Feed Microscopy usually contains:

• A collection of feed ingredient standards:  (100 g for each ingredient is enough.)

•      A collection of common weed seeds:

• Binocular stereo microscope:

• Compound microscope: (from 50x to 500x magnification and metal plate,)

• Sieve set: (4 sieve set with mesh sizes of 1 mm – 0,5 mm – 0,250 mm – 0,125 mm is recommended.)
• Electronic analytical scale (0,0001 g):

• Reagents: Tetrachloroethylene and petroleum ether