Fiber in Animal Nutrition

Fiber in Swine Nutrition 22 fiber level must also be maintained during lactation and that there is a risk for consti- pation problems if the difference in fiber content between gestation and lactation diet is too great. Additionally several scientific studies have investigated the effects of different dietary fiber levels on sow physiology, colostrum production and piglet performance. Loisel et al. (2013) fed 29 nulliparous sows with high fiber (23.4%TDF) or low fiber (13.3% TDF) diets from gestation day 92 until far- rowing. In this trial increasing the TDF by 13.4% percent points in gestation affected the sows colostrum composition (higher lipid content) but not the milk yield. Furthermore it increased the colostrum intake of piglets with low birth weights which resulted in de- creased preweaning mortality. The allocated investigation of the hormones associated to lactogenesis in this trial could not explain these observations. In the future sow behavior and piglet conditions need to be evaluated more closely when investigating the effects of dietary fiber in and around farrowing. Digestion Insoluble and bulking fiber like cellulose and the lignin-cellulose complex fill the gut and have a good water binding capacity. The bulking effect and the excitation of intestinal receptors by the edges of the particles pro- mote the onward movement of the digesta in the gut. A sufficient fill of the gut and intact peristalsis of the intestine contributes to satiation and prohibits constipation in and around farrowing. Soluble and fermentable fibers in turn provi- de the nutritional basis for lactic acid bacteria in the hind gut. Especially pectin plays an important role when providing fermentable fiber to sows because it is the main compo- nent in common feed materials like sugar beet pulp and apple pomace. Thereby short chained fatty acids (SCFA) are released and contribute to daily energy supply. While diets for piglets should be formulated without using higher quantities of soluble and fermentable fiber sources because the digestion in the hind gut is not fully de- veloped, adolescent pigs efficiently utilized these feed sources. Renteria-Flores et al. (2008) investigated the effect of feeding diets high in insoluble fiber, high in soluble fiber or high in insoluble and soluble fiber to gestating sows compared to a control group. The results showed that soluble fiber and insoluble fiber differently affects nutrient digestibility. Increasing soluble fiber intake increases digestibility of energy, soluble fiber and insoluble fiber without taking influence on N utilization. Contrary increasing insoluble fiber decreased digestibility of energy, N and soluble fiber. The digestibility of insoluble fiber was not affected. This again demonstrates that insoluble f iber and soluble f iber as well as their diet range differently affect the digestibility of the diet. Hereby age also affected the fiber digestibility. Multiparous sows had the better ability to digest insoluble fiber than nulliparous sows. In summary the results of this trial suggest that high levels of fiber can be included in diets for gestating sows without negatively affecting the diet. Thereby always taking the type of fiber in the feed materials and their physicochemical properties into account. Initially there is no reason to believe that adding an insoluble and bulking fiber without a significant energy or protein content to a diet might improve the digestibility of crude nutrients. Surprisingly numerous trials with © ERLING Verlag