High-Fibre feeding in gestation

Gestating sows are usually fed low levels of feed, which may not provide sufficient satiety, and does not allow sows to fully fulfil their motivation to express foraging and feeding behaviours. Feed restriction may therefore lead to high occurrences of non-feeding oral activities, including stereotypies, and restlessness and aggressive behaviour in grouphoused sows, which are interpreted as signals of sustained feeding motivation and frustration. Inclusion of fibres in the diet reduces the energy density of diets and therefore allows for larger meal sizes without increasing the energy supplied. Moreover, dietary fibres influence the mechanisms that enhance satiation and satiety at the sensory, postingestive and post-absorptive levels. This chapter reviews the impact of dietary fibres on behaviour and welfare of gestating sows, and describes their potential consequences for performance. Dietary fibres generally reduce the occurrence of stereotypies and decrease restlessness and activity, with some studies also reporting reduced aggression. These effects are most likely related to behavioural and physiological mechanisms underlying the impact of dietary fibres on satiety and feeding motivation. The extent of the response to dietary fibres is, however, variable and depends on the characteristics of the fibrous diet (inclusion rate, fibre source, physicochemical properties), housing and feeding conditions, and characteristics of the sows, especially parity, with greater effects in younger sows. Dietary fibres provided during gestation usually result in increased feed intake of sows during lactation, probably due to their effects on the size and capacity of the gastrointestinal tract. Studies on the effects of fibres on reproductive performance are scarce and show variable results, which might partly be attributed to over- or underestimation of the energy content of the diet during pregnancy. In conclusion, dietary fibres generally have a beneficial effect on the behaviour and welfare of gestating sows which are restrictedfed. The impact of high fibre diets during gestation on reproductive performance over multiple successive cycles in group-housed sows merits further research.