Fiber in Animal Nutrition

Fiber in Swine Nutrition 20 ties can be associated to 1) mechanical or 2) hormonal/chemical satiation. Mechanical satiation is associated to fibers with bulking features and goodwater binding capacity that support a good gut fill (i.e. cel- lulose and lignin-cellulose complex). These characteristics contribute to good swelling of the feed and distension of the receptors in the stomach. Furthermore including fibrous feedstuffs takes influence on the gastric fill and gastric emptying rate. High insoluble fiber levels can prevent the development and early drain of the liquid phase (Miguel et al. 2001). The bulking effect also promotes the onward movement of the digesta in the gut. Hormonal/chemical satiation is associa- ted to fermentable fibers that provide the nutritional basis for lactic acid bacteria in the hind gut (i.e. pectin). In the course of bacterial degradation short chained fatty acids (SCFA) are released and contribute to daily energy supply. SCFAs like acetic, propionic or butyric acid are produced over a longer period of time, stabilize the insulin and glucose level in the blood and thereby contribute to long term satiation. Finding parameters to clearly define satia- tion is difficult. Apart from the physiological factors mentioned above others can contribute to hunger or satiation behaviour (time, perso- nal, ambient temperature etc.). Therefore the data collected is sometimes incomprehensive or even contradictory when the effect of dif- ferent fiber sources is investigated. The influence of different fibrous feed stuffs on the feedingmotivation of adult female pigs was investigated by Souza da Silva (2012). In a latin square design pigs were fed diets containing one of three different fiber com- ponents (lignocellulose LC, citrus pectin Pec, resistant starch RS) compared to a control diet (C high starch, low fiber). In between the meals fed twice a day the pigs had access to a feeding automat. By turning a wheel fitted to the automat the pigs could work for a feed reward. Providing 5%Arbocel lignocellulose resulted in a lower number of wheel turns compared to the control, citrus pectin and resistant starch group. This indicates a low feeding motivation and therefore a good satiation (figure 3). Another trial (De Leeuw et al. 2004) evaluated the inf luence of low and high concentrations of fermentable NSPs on the glucose and insulin level in sows using wheat middlings or sugar beet pulp, respectively. Additionally the behaviour of the sows was evaluated throughout a 14 hour period. Defining satiation through reduced physical activity (figure 4). Figure 3: Feeding motivation of female pigs fed with different fiber sources (Souza da Silva 2012; modified) 500 450 400 350 300 250 200 1 2 3 4 5 6 7 No. of wheel turns LC Pec RS C © ERLING Verlag