Page 90 - Poultry-Punch April 2020 edition

POULTRY PUNCH ARTICLE

Most commonly used spot tests

Constituent Test Remark
Thiram (Pesticide 100g sample+ 50m1 chloroform shake (5min). Filter Filtered chloroform extract turns amber to
in maize) the contents with Whatman filter paper 1. Add few brown colour with in 1 -2 min indicative of
crystals of cuprous iodide to filtrate and shake thiram
Mahua cake In water extract of test feed add conc. H SO Violet or pink colour indicate the presence of
2 4
Mahua cake
Linseed meal Test feed is treated with 1-2 drops or more of dilute Depending upon the amount of HCN
H2SO4 in microtest tube. The mouth of test tube is produced a more or less intense blue colour
covered with a disk of filter paper moistened with a appears
drop of reagent
Common salt To 1g sample, add 100m1 distill water, stir & filter. White turbidity indicates presence of salts
Leather meal Pick up brown to black particles from sample and No colour change
place on Petridis, add 3-5 drops of ammonium
molybdate, stand for 5-10min
Fish meal quality Put 2-3g of test sample in a 100m1 beaker and add Heavy orange colour indicates presence. of
(presence of NPN) 1 0-15m1 distill water stir. After 2-3 min, add 3-5 NPN. intensity of orange colour of precipitate
drops of test extract on white porcelain plate and depend on, amount of NPN
add 2-3 drops of mercuric-potassium iodide alkaline
solution
Decomposition 5g test sample in 250m1 flask. Prepare cork, to Test paper darkens quickly, if sample is badly
test (animal and fit 2.25” of filter paper strip pinned to bottom & decomposed
marine products) moistened with saturated lead acetate. Add 50m1
dilute H SO (5m1 acid + 45m1 distill water) & insert
4
2
cork. Stand for 16hour.
Hoof or horn Place 2-3 particles of amber colour test sample Test particles if hard and tough –hoof and
into a evaporating dish, add 5m1 glacial acetic acid, horn ,soft and swollen gelatin
stand for 60 min

Urease activity in Spread the sample uniformly on petridish, glazed paper Inadequate heat treatment- particles turn red
soyabean meal with white background. soybean meal Spray cresol within a minute. Adequate heat treatment- Few
red (0.1 % solution) and thymol blue (0.1% alcoholic particles (<10%) slowly develop red coloration.
solution) reagent mixture (80m1 cresol red, 20m1
glycerol/sorbitol, 2g urea and few drops of thymol blue)
and examine for colour.

Size: Size of the grains governs its energy Homogeneity: Presence of contaminants contain fungal growth. Clumps in mineral
and protein due to proportional decrease/ like other grains, broken grains, husks, ingredients are not suitable for premixing.
increase in seed and its coat. Smaller the weed seeds, infested seeds is viewed. In Smell: Standing near the stock
grain lower will be the nutrient contents the oil seed cakes, closer observation will immediately indicate any difference from
due to more proportion of seed/grain coat. reveal the presence of fibrous material like the normal smell. Musty odour indicates
To evaluate the weight of cereals about hulls in de-oiled groundnut cake, rice polish the beginning of fungal contamination or
100grains or fixed volume is taken. Higher contaminated with husk. Presence of clumps boring insects. To detect rancidity in oil rich
weight indicates a higher ME value. This in oilseed meals indicates inadequate cooling feed ingredients this is the best method.
technique is called Test Weight. of the cake before packing. Clumps may Odour of petroleum products is suggestive

90 April, 2020