Pig International - November 2017 - 32
32 ❙ PigInternational
Animal feed formulation: Fiber
matrix secrets revealed
A complex matrix of fiber values and fiber sources can reveal how
much more we need to learn before we are ready to incorporate
novel thinking into everyday animal feed formulations.
The case has been made often regarding the futility of
keeping crude fiber as anything but an index of historical appeal when it comes to define fiber quantity and
quality in a feed or ingredient. Ruminant nutrition
scientists have developed a new fiber system based on
two better chemical analytical values, namely acid-detergent fiber (ADF) and neutral-detergent fiber (NDF),
but it is of rare if any use for monogastric animals.
Terms like water-holding capacity, solubility and fermentability have emerged for poultry and pig diets, and
there have been several, but not enough, scientific reports
trying to establish a working method on how to use them
in everyday formulation practice. Results remain frustrating, if only because we lack two basic things:
■ A comprehensive database of all ingredients describing their concentration in these new fiber values.
Such an undertaking is not impossible, but it is
rather expensive, given the plethora of fibers within
■ set of values to be used as feed specifications during formulation that will relate ingredient concentration in each fiber value with feed final figures.
Fiber sources and their values
An interesting array of fiber values for a number of
fiber sources can be seen in the table. It is lamentable
that this table, which has just been published, does not
include other ingredients as well, but given the complexity of such research, it remains an excellent start.
Modern fiber thinking is now beyond chemical
analyses as we focus more on biological values.
One most notable aspect that fiber enthusiasts will
soon observe by studying these data and any such
similar information is that there is no strong correlation between any of the values presented in this table.
There are some patterns, explained by similar forms
of fiber among different ingredients, but the breadth of
differences even among the same family of fibers, and
the number of such families, makes their combination
in each ingredient almost unique - a fiber signature!
Of high note are three ingredients with high solubility, namely apple pomace, dried sugar beet
pulp and pure pectin. All are rich in pectin,
yet only one of them, sugar beet pulp, has a
water-holding capacity that can be attributed to its high pectin level.
This is a most confusing index of fiber quality because scientists
have not determined yet how to
incorporate it into
Fiber is everywhere and comes in a great
variety of forms of differing biological value.
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www.WATTAgNet.com ❙ November/December 2017