AFIA - Laboratory Methods Manual - Australian Fodder Industry ...

Reagents:
1. Neutral Detergent Solution (NDS), prepared as follows (all chemicals reagent grade):
Note: A total of 2.0 L of NDS should be used during all digestions regardless of the number
of samples. The following formula gives weights required for 1.0L.
Note 2: If bulk solutions are made and stored prior to use, care MUST be taken to ensure that all
components are mixed back into the solution before any solution is decanted. Failure to do
so may result in significant error.
a) Place 18.61 ± 0.01 g of EDTA (disodium ethylenediaminetetraacetate, C 10 H 14 N 2 Na 2 O 8 x
2H 2 O) and 6.81 ± 0.01 of sodium tetraborate decahydrate (Na 2 B 4 O 7 x 10H 2 O), in a
beaker and add some distilled water and heat until dissolved.
b) Add 30.0 ± 0.1 g sodium lauryl sulphate (C 12 H 25 OSO 3 Na), 10.0 ± 0.1 mL of triethylene
glycol and 4.56 ± 0.01 g disodium hydrogenphosphate (Na 2 HPO 4 ).
c) Add water and heat until dissolved. Mix and dilute to 1000 mL. Check pH which should be
in the range 6.9 - 7.1.
2. Sodium sulphite, anhydrous
3. Alpha-amylase, 17,400U/mL, Heat-stable, ANKOM #FAA standardised as per Appendix
1.8R(1).
4. Distilled water (dH2O)
5. Acetone
Procedure:
Note: Analyses are performed only on samples previously dried at 55 to 60 o C (maximum) and
ground to pass a 1 mm screen. Operators should wear gloves when handling filter bags.
1. Weigh the filter bag, record weight (W1) and then zero balance. The bags have negligible
moisture content and do not need to be pre-dried.
2. Weigh 0.50 ± 0.05 g, of well-mixed laboratory dry sample directly into filter bag. Record weight
to at least 0.1 mg (0.001 g) accuracy (W2).
3. Seal the bag closed within 1 cm of the open edge using the heat sealer. Weigh and seal one
empty bags to be run as blanks during analysis.
4. Spread sample uniformly inside the filter bag. This should be done by shaking and lightly
flicking the bag to eliminate clumping.
5. Weigh a second sub-sample for laboratory dry matter determination.
6. Pre-extract lipid from all samples with acetone. Place bags into a glass container with a lid.
Pour enough acetone into container to cover bags and secure top. Shake the container 10
times and allow bags to soak for 10 min. Repeat with fresh acetone. Pour out acetone and
place bags on a wire screen to air dry.
7. The Bag Suspender is composed of nine individual baskets, one centre post and one spring.
Place three bags per basket, maximum 24 bags per run and stack baskets on centre post,
each basket rotated 120 degrees from previous one. The ninth basket remains empty and
acts as a top for the eighth basket.
AFIA Laboratory Methods Manual – v7 September 2011 Page 46 of 103