Development of gut and gut-associated lymphoid tissues in piglets: role of maternal environment - The Gestating and Lactating Sow - page 335

weight piglets (Michiels et al. , 2013). These differences could be attributable to differences
in substrate availability or to modification in composition of intestinal microbiota, as
suggested in rats with IUGR (Fanca-Berthon et al. , 2010).

Most of the differences reported during the perinatal period (D'Inca et al. , 2010; Wang et
al. , 2005; Xu et al. , 1994b) are still present in pigs with IUGR early after weaning (Michiels
et al. , 2013) and in adulthood (Alvarenga et al. , 2013). Factors other than digestive defects,
such as changes in metabolic activity and hormonal imbalances, might be involved in
the reduction of growth potential (Wang et al. , 2008). The most consistently depressed
expression among growth factors is that of serum insulin-like growth factor 1 (IGF-1)
and IGF-1 gene expression in tissues such as muscle, liver, kidney and adipose tissue
(Chen et al. , 2011; Gondret et al. , 2013).

In conclusion, defects in foetal nutrition have huge effects on offspring gut physiology and
delay gut maturation. Such impairments in gut barrier and immune system development
contribute to the higher postnatal mortality and lower growth rate in surviving piglets
with IUGR (Morise et al. , 2008; Quiniou et al. , 2002).

15.3.3 Maternal n-3 polyunsaturated fatty acids and offspring gut maturation

Dietary polyunsaturated fatty acids (PUFA), such as linoleic acid (LA, 18:2n-6), α-linolenic
acid (ALA, 18:3n-3) and their longer-chain derivatives including eicosapentaenoic acid
(EPA, 20:5n-3), docosapentaenoic acid (DPA, 22:5n-3) and docosahexaenoic acid (DHA,
22:6n-3), for the n-3 family, and arachidonic acid (ARA, 20:4n-6) for the n-6 family are
essential components in cells of all tissues and contribute to the normal growth and
development of physiological functions in newborn piglets. The fatty acid composition
of piglet tissues is linked to the composition of sow diets during gestation and lactation.
Providing linseed oil (rich in ALA) in gestating sow diets increases PUFA in plasma
and placenta of sows as well as in plasma and tissues of piglets at birth and during the
suckling period (De Quelen et al. , 2013). Dietary linseed oil also increases the contents of
ALA, EPA and DPA in sow milk (De Quelen et al. , 2013; Farmer et al. , 2009). Vegetables
sources such as (extruded) linseed, walnut or rapeseed oil, and also marine sources such
as menhaden fish oil and shark-liver oil, could be used to supply n-3 PUFA in sow diets
(Fritsche et al. , 1993; Rooke et al. , 2001a,b). The effects of feeding other fat sources,
such as CLA and omega 3, on the immune system of sows are covered in more details in
Chapter 16 of this topic (Bontempo and Jiang, 2015).

Maternal supplementation of n-3 PUFA during gestation and lactation has no beneficial
effects on sow and litter performance (de Quelen et al. , 2010; Quiniou et al. 2010).
However, inclusion of extruded linseed in sow diet during gestation and lactation may
increase survival rate at weaning of piglets with birth weights close to the mean litter birth
weight, but not piglets with small birth weight (<1 kg) (Quiniou et al. 2010). Feeding
linseed meals to late-pregnant and lactating sows has also positive effects on post-
weaning growth of piglets that may be explained by an improvement of their immune
resistance (Farmer et al. , 2010). The n-3 PUFA are known for their anti-inflammatory
properties and their beneficial effects on intestinal inflammatory disorders. Surprisingly,