Agriculture Reference
In-Depth Information
et al.
, 1994, 1996). To prevent excess body weight gain and fat deposition, which may
slow down the farrowing process and promote locomotion problems, restricted feeding is
usually applied during gestation. The level of feed provided corresponds to approximately
40-60% of the sows' voluntary intake (Lawrence
et al.
, 1988; Van der Peet-Schwering
et
al.
, 2004), which results in a low level of satiety and a reduced performance of appetitive
and consummatory sequences of feeding behaviour. This feeding level might not fulfil the
behavioural needs of pregnant sows, especially their motivation to express foraging and
feeding behaviours. Feed restriction has, therefore, been linked to behavioural problems
widely reported in the literature, such as stereotypies at meal time (Lawrence and Rushen,
1993) and aggressive behaviour in group-housed sows due to feeding competition
(Terlouw
et al.
, 1991). Both of these behavioural problems have been considered to reflect
an unfulfilled feeding motivation and impaired welfare (De Leeuw
et al.
, 2008; Meunier-
Salaün
et al.
, 2001; Philippe
et al.
, 2008). Moreover, excessive feed restriction could also
be detrimental for the birth weight and viability of piglets, as well as for the weaning-to-
oestrus interval or conception rate, both of which having been associated with low body
fat reserves at farrowing (Campos
et al.
, 2012; Van der Peet-Schwering
et al.
2003b).
Societal debate on intensive animal production systems highlighted some doubts on
the welfare status of farm animals (Eurobarometer, 2005). These doubts particularly
concern the feeding practices where the inability of sows to express spontaneous feeding
behaviours fails to satisfy one of the five freedoms considered as a requirement in
legislation: the freedom to express normal behaviour (Council Directive 1991 630/EEC;
EC, 1991). A way of satisfying feeding motivation in pregnant sows while maintaining
a restricted energy supply to prevent concomitant excessive weight gain and fat
deposition, is to provide sources of fibrous material as a rooting substrate or to include
fibrous ingredients in the diet. This alternative way was considered in the reinforced
implementation of European legislation on pig welfare (Council Directive 2001/88/EC;
EC, 2001). The supply of fibrous components in diets or as rooting material may promote
nutritional satiety, for instance, by increasing feed bulk without increasing the energy and
nutrient allowances, and behavioural satiety through their impact on the appetitive and
consummatory sequence of the feeding behaviour.
The objective of this chapter is to describe the major effects of dietary fibres used for
pregnant sows. The characterization of fibres and their putative effects on satiety will be
discussed, as well as the consequences of fibrous diets on performance and behavioural
activity in relation to animal welfare.
5.2
Dietary fibres: definition, sources and characteristics
The definition of dietary fibres as non-digestive constituents from plant cell walls
was introduced by Hipsley (1953). Thereafter, it has been widely discussed with new
proposals from experts, and a final definition has been adopted in the 2009 meeting of
the Codex Alimentarius Commission (Berridge, 2009; Phillips and Cui, 2011). Dietary
fibre is defined as carbohydrate polymers with ten or more monomeric units which are
not hydrolysed by the endogenous enzymes in the small intestine of humans.
