GB/T 6433-2025Determination of crude fat in feeds (English PDF)

Foreword

This document was drafted in accordance with the provisions of GB/T 1.1-2020

"Directives for standardization - Part 1.Rules for the structure and drafting of

standardizing documents".

This document replaces GB/T 6433-2006 "Determination of crude fat in feeds".

Compared with GB/T 6433-2006, in addition to structural adjustments and editorial

changes, the main technical changes are as follows.

a) DELETE the sampling (see Clause 7 of the 2006 edition);

b) MODIFY the sample preparation requirements (see 4.4 of this document, Clause

r 8 of the 2006 edition);

c) ADD the pre-extraction requirements for extruded pellet feeds (see 4.1 and 4.5.1

of this document);

d) MODIFY the unit of determination results to percentage (see 4.6 of this document,

Clause 10 of the 2006 edition);

e) MODIFY the precision requirements (see 4.7 of this document, Clause 11 of the

2006 edition);

f) ADD the filter bag method (see Clause 5 of this document).

This document has modified and adopted ISO 6492.1999 "Animal feeding stuffs -

Determination of fat content". Compared with ISO 6492.1999, this document has made

the following structural adjustments.

- 4.1 corresponds to Clause 4 of ISO 6492.1999;

- 4.2 corresponds to Clause 5 of ISO 6492.1999;

- 4.3 corresponds to Clause 6 of ISO 6492.1999;

- DELETE Clause 7 of ISO 6492.1999;

- 4.4 corresponds to Clause 8 of ISO 6492.1999;

- 4.5 corresponds to Chapter 9 of ISO 6492.1999;

- 4.6 corresponds to Clause 10 of ISO 6492.1999;

- 4.7 corresponds to Clause 11 of ISO 6492.1999;

- DELETE Clause 12, Annex A and bibliography of ISO 6492.1999;

- ADD Clause 5.

The technical differences between this document and ISO 6492.1999 and their reasons

are as follows.

- ADD the pre-extraction requirements for extruded pellet feeds (see 4.1 and 4.5.1

of this document), to meet the needs of crude fat testing of extruded pellet feeds in

China;

- REPLACE ISO 3696 with GB/T 6682 (see 4.2.1 of this document), to meet the

technical characteristics of China;

- DELETE the content of sampling;

- REPLACE ISO 6498 with GB/T 20195 (see 4.4 of this document), to meet the

technical characteristics of China;

- MODIFY the sample preparation requirements (see 4.4 of this document, Clause 7

of ISO 6492.1999), to meet the needs of crude fat testing in different forms of feed

raw materials and feed products in China;

- MODIFY the unit of determination results to percentage (see 4.6 of this document,

Clause 10 of ISO 6492.1999), to be consistent with the provisions of the national

standards for feed labeling in China;

- MODIFY the precision requirements (see 4.7 of this document, Clause 11 of

ISO6492.1999) to be applicable to the actual technical level of crude fat testing of

feeds in China;

- ADD the filter bag method (see Clause 5 of this document), to meet the

development trend of crude fat testing technology at home and abroad and meet

the actual testing needs of feed industry of China.

This document has made the following editorial changes.

- MODIFY the standard name to "Determination of crude fat in feeds";

- CLARIFY the ISO 6492.1999 method as "Soxhlet extraction method", to

distinguish the added filter bag method.

Attention is drawn to the possibility that some of the elements of this document may be

the subject of patent rights. The issuing authority of this document shall not be held

responsible for identifying any or all such patent rights.

This document was proposed by and shall be under the jurisdiction of National

Technical Committee on Feed Industry of Standardization Administration of China

(SAC/TC 76).

Determination of crude fat in feeds

1 Scope

This document describes the Soxhlet extraction and filter bag methods for the

determination of crude fat in feeds.

This document applies to the determination of crude fat in compound feeds,

concentrated feeds, concentrate supplements, and feed ingredients (except algae and its

processed products).

To ensure the effectiveness of crude fat determination in this document, feeds are

divided into the following two categories, and Category B products need to be

hydrolyzed before extraction.

Category B.

- animal-derived feed ingredients, including dairy products;

- plant-derived feed ingredients from which fats cannot be extracted without prior

hydrolysis, such as gluten, yeast, soya and potato proteins, as well as heat-treated

feed ingredients and feed products;

- compound feeds, concentrated feeds, and concentrate supplements that use animal-

derived feed ingredients and/or plant-derived feed ingredients from which fats

cannot be extracted without prior hydrolysis, where at least 20 % of the crude fat

comes from these feed ingredients.

Category A.

- compound feeds, concentrated feeds, concentrate supplements, and feed

ingredients other than category B.

2 Normative references

The following referenced documents are indispensable for the application of this

document. For dated references, only the edition cited applies. For undated references,

the latest edition of the referenced document (including any amendments) applies.

GB/T 6682 Water for analytical laboratory use - Specification and test methods

(GB/T 6682-2008, ISO 3696.1987, MOD)

GB/T 20195 Animal feed - Preparation of test samples (GB/T 20195-2024, ISO

6498.2012, MOD)

carbide chips (4.2.7) and weigh (m1) to the nearest 0.0001 g, accurately transfer 50 mL

of petroleum ether extract into this flask.