Fiber utilization
Impact of age
Adult pigs have a more developed and larger GI tract, a
lower feed intake per kg body weight, a slower digesta
transit time and a higher cellulolytic activity than young
pigs. This resulted in greater capacity of sows to digest
fibrous components compared to young pigs [27] and it
was shown that sows digest a larger part of the NSP in
the small intestine than growing pigs [28]. They also
showed that sows have a higher capacity to digest insoluble
NSP, whereas the difference in digestibility of soluble
NSP between growing pigs and sows were only
marginal. It was suggested that because of the increased
capacity to digest fibrous feedstuff by increased age and
body weight, at least two different energy values, one for
growing-finishing pigs and one for sows should be used
for most feed ingredients in pig diets [4]. This has been
implemented in the INRA net energy system for pigs
(www.evapig.com).
In weaned pigs, age affected the total tract apparent
digestibility of all dietary components except for NDF,
with higher values at five than at three weeks postweaning
[29].
Impact of pig breed
Digestive capacity and potential body protein deposition
are two important traits associated with pig performance.
However, in commercial pig breeding research has