This ppt is all about concept of microscopy in evaluating animal feed to determine different contaminants and adulterant.

1. Latest Concepts in Feed
Microscopy
Department of Animal Nutrition
College of Veterinary Science and Animal Husbandry, Anjora (Durg), C.G.
Course Name: Advances in Feed Technology
Course No.: ANN 708 (1+0)
Course Teacher: Dr. Meenu Dubey
Student Name: Rakesh Sheel
Class: PhD II Semester
Session: 2022- 23

2. What is Feed Microscopy?
Evaluation of the quality of feeds and extent of
adulteration and contamination with the help of
microscope
Simple, rapid and less time taking technique
Very affordable and useful for preliminary examination
of feed ingredients

3. Objectives and Importance
Proof of identity and purity of feed ingredients
Establishment of impurities and prohibited
contaminants
Recognition of undesirable elements such as
insects and moulds
(Kamphues et al., 1998)

4. Objectives and Importance
Indication of the composition of compound feeds
Complementary to the chemical feed analysis in lab
To stop bovine spongiform encephalitis (BSE), European
commission has determine constituents of the animal origin in feed
using a microscopic method.
(European community, 1998;
Von holst et al., 2006)

5. Basic Requirements
Analyst must have knowledge of biology of ingredients as
well as adulterants
Analyst require training and experience to improve visual
identification skill
Require collection of reference materials and dedicated
expert systems
Knowledge of sample preparation for various adulterant is
needed

6. Types of Feed Microscopy
Qualitative Feed Microscopy
Identification and evaluation
of ingredients and foreign
materials, alone or in mixture,
via either surface features
(stereomicroscopy) or cellular
characteristics (compound
microscopy)
Quantitative Feed Microscopy
Subjective, proportioned
measurement of ingredients
in finished feeds or of
contaminants and adulterants
in ingredients in finished
feeds or of contaminants and
adulterants in ingredients

7. Sample Preparation
Screening: about 10 g of the ground sample is placed on 40 mm
mesh sieve to separate particles using RO- Tap shaker (to remove
the fine starchy dust and other fine particles)
Floatation technique: sample (expeller pressed cakes) is soaked in
chloroform; stirred and allowed to settle (to separate organic and
inorganic fractions)
Supernatant is then dried and used for microscopic identification

8. Stereomicroscopic Inspection Process
Set the microscope at lower magnification and adjust the focus
Spread a fraction of sample on petri dish and examine under the
microscope
Inspect coarse objects thoroughly starting from one end to
other
Adjust the proper magnification to examine accurate
characteristics
Extra ingredients other than feedstuffs are called
CONTAMINANTS if found in small amount and ADULTERANTS if
in large amount

9. Microstructure of Adulterants
 Compound feeds and feed ingredients are adulterated with rice husk,
groundnut husk, castor husk, wheat straw and saw dust.
Acacia nilotica/ saw dust:
 Whitish brown in color and
woody in appearance,
 Thick, hard, opaque and
somewhat lustrous
 Do not break even after
applying pressure with
needle and tweezers
Groundnut husk:
 Outer portion is yellow and inner
portion is white opaque and glossy
 Husk fragments possess longitudinal
ridges forming a reticulate patter
 Thin, papery, red particles (pericarp
of kernel)

10. Castor husk:
 Dark brown to black outer
layer
 Whitish yellow inner layer
 Hard and exhibit a woody
appearance

11. Microstructure of Adulterants
Wheat husk:
 Elongated, dull white to
brownish yellow in color
 Thin, semi glossy and
semi transparent
 In some of the particles
fibrous strands are
clearly visible
 Rice husk:
 Yellow in color and irregular in shape and size.
 Hard and possess sharp edges.
 Flake like appearance with longitudinal striations
forming a cross hatching pattern on the surface
of the particles

12. Detection of over-heated maize
Observations were made with
stereomicroscope and compound
microscope.
Sample 01 shows black parts that
resemble charcoal at the edges of some
particles, and small black spots.
Sample 2 had no black parts.
(Newsletter 2014 IAG section Feed Microscopy)

13. Unstained Microscopic Pictures of Processed
Animal Protein (PAPs)
< 0.1% concentration of MBM in PAPs can be detected (Liu et al., 2011)

14. Stained Microscopic Pictures of Processed
Animal Protein (PAPs)
Treated with tetrachloroethylene (Liu et al., 2011)

15. Spot and Other Chemical Test
 Drugs and other feed
additives are tested for
presence or absence as a
quick check of correct
formulating and mixing
 A small amount of sample
sprinkled thorough 40 mm
mesh on the surface of a
drop of reagent in a white
spot plate and reaction
should be observed under
20 X resolution
Reagents Observations
1N HCL Effervescence (carbonates)
Quimociac
reagent
• Effervescence without precipitates (carbonate)
• Yellow precipitate with effervescence (Phosphates)
• Yellow precipitate without effervescence (di or
monosodium phosphates)
0.1 N Silver nitrate White precipitate is insoluble in nitric acid but soluble
in conc. ammonium hydroxide(Salt)
Distilled water Milky white solution (milk product)
Potassium Ferro/
ferricyanate
Blue color (ferric salts)
Barium chloride Form precipitates which are insoluble in conc. HCL
(sulfates)

16. Conclusions
 Feed microscopy is a simple, rapid, affordable and real time cutting age
imaging technique.
 It is very helpful in determining and evaluating qualitative aspect of feed
ingredients very early in feed plant.
 This technique needs technical knowledge and professional skill and
experience
 It gives the preliminary idea about the type of adulteration, insect or mould
infestation etc. to empower the regulation of feed purchase.
 With the use of microscopic spot on test, qualitatively determination of the
presence of different inorganic chemical or adulterant in the sample could
be possible.
 Overall this technology has the potential to optimize finished feed product
and ultimately contribute to improve animal production.

17. Thank you