Agriculture Reference
In-Depth Information
Long-chain polyunsaturated fatty acids are substrates for prostaglandins and eicosanoids
and, therefore, subsequently influence cytokine expression (Alexander, 1998). The n-3 and
n-6 fatty acids (FA) are essential constituents of plasma membranes in the brain, central
nervous system, and vascular systems, making them critical components during rapid
tissue formation (i.e. gestation and foetal growth). These PUFA give rise to different types
of eicosanoids, which play important roles in the regulation of inflammatory reactions,
blood pressure, and platelet aggregation. Dietary CLA also affect the fatty acid composition
of colostral fat but, more interestingly, they positively affect immunologic variables in
colostrum, as seen by an increase in IgG concentrations (Bontempo
et al.
, 2004).
Recent studies have shown that several fatty acids appear to improve body function and
may be important to some physiological processes. However, those findings are often
contradictory, which may be due to the different levels of fatty acids supplemented as well
as the duration of the fatty acid supplementation. This review summarizes the current
knowledge on the effects of supplementation with omega FA and CLA in the maternal
diet on performance, fatty acid profile and immune status of sows and piglets. In addition,
the strategies for using both types of fatty acids are also discussed.
16.2
Use of fats and oils in sow's diets
The fat and energy contents in milk play an important role for piglet survival, and an
improvement in litter weight by adding fat to sow diets has been observed. Supplementing
the diet of sows with fat during late pregnancy increases total lipids and lactose in
colostrum, and also increases colostral IGF-I concentrations (Farmer and Quesnel, 2009).
In order to reduce the fat and energy losses encountered by sows during lactation, the
addition of animal fats or vegetable oils into late gestation or lactation diets is widely used
in commercial farms. Inclusion of dietary fat in late-gestation may improve colostrum
yield of sows and increase neonatal piglet survival (Hansen
et al.
, 2012). However, an
increased plane of nutrition during late gestation may have a negative effect on sow
performance during lactation. This topic of transition feeding is covered in more details
in Chapter 7 (Theil, 2015). An excess of energy intake during late gestation was shown
to inhibit the development of mammary secretory tissue and increase the loss of body
condition during lactation as a result of reduced feed intake (Laws
et al.
, 2009a). It has
also been suggested that the type of dietary fat rather than the total fat content of the
diet is important in determining neonatal outcome (Laws
et al.
, 2007a). Therefore,
supplementing dietary fats and oils should be done carefully and appropriately.
16.3
Omega fatty acids (n-3 and n-6 FA)
The n-3 and n-6 FA are polyunsaturated fatty acids (PUFA) and can be distinguished from
each other based on the location of the first double bond from the methyl end. Therefore,
the n-3 and n-6 FA are metabolically and functionally distinct, are not interchangeable,
and may have opposing physiological functions (Calder, 2003). Among PUFA, α-linolenic
acid (ALA; C18:3n-3) and linoleic acid (LA; C18:2n-6) are classified as nutritionally
