Role of Intestinal Viscosity in Interference of Fat Digestion General remarks

Increases in intestinal viscosity of broilers are mainly caused by feeding higher proportions of soluble NSPs such as the soluble pentosans in rye and wheat and soluble mixed linked P-glucans in barley. Although both rye and barley are comparable in soluble NSP content, the relationship between water extract viscosity profile and soluble NSP concentration is quite different (Fig. 9.1). It has been emphasized that, in addition to chemical analysis of polysaccharides, their physical properties...

Digestibility of fat and fatty acids

Carbohydrase supplementation of broiler diets based on rye, rye wheat, triticale or barley resulted in larger improvements in fat digestibility if the dietary fat was of animal origin compared with plant. In simple terms, it could be concluded that there is more scope for improvement in fat digestibility when it is low to begin with. This interpretation is probably the reverse of how such data should be viewed. An increase in intestinal viscosity depresses fat digestibility more in animal...

Factors Affecting Fat Digestibility

From the above section it becomes clear that a variety ofevents have to take place in a coordinated manner within a relatively short time (see below) if high quantities of ingested fat are to be absorbed. Hence, it is useful to take note of several factors that influence fat digestibility in broilers before dealing with the effects of intestinal viscosity caused by ingestion of cereal grain soluble non-starch polysaccharides (NSPs) and consequently the effects of the intestinal viscosity...

Lipase availability

Lipase activity was reported to be low in the very young turkey Krogdahl and Sell, 1989 and chick Nir et al., 1993 and lipase addition to a tallow-containing diet was shown to improve fat digestibility Polin et al., 1980 . Noy and Sklan 1995 did not detect any increase in ileal fat digestibility in chicks between 4 and 21 days of age 6 unsaturated fat in the diet despite an age-related increase in lipase secretion into the duodenum. At present, no final conclusion can be drawn under which...

Principles of Fat Digestion in Broilers

Digestion and absorption of fat in poultry was extensively reviewed by Krogdahl 1985 . Briefly, the initiation of fat digestion seems to start with a possible onset of fat emulsification in the upper digestive tract but mainly with the entrance of digesta into the duodenum, where it is mixed with the secretions of the exocrine pancreas and gall bladder, which contain lipase, co-lipase and conjugated bile salts, respectively. Bile salts and phospholipids facilitate progressive fat...

Degree of unsaturation and polarity of fatty acids

LCSFAs C16 0, C18 0 are more non-polar than unsaturated long-chain fatty acids of the C18 family and among these fatty acids the polarity increases as the number of double bonds increases. Among the saturated fatty acids C8 0 . . . C18 0 , the polarity increases as the chain length decreases. The more non-polar a fatty acid is, the more it relies on an adequate presence of bile salts and phospholipids for adequate emulsification. It has been shown that medium-chain saturated fatty acids MCSFA...

Feed passage through the digestive tract gut motility and unstirred waterlayer resistance

Carbohydrase supplementation of diets based on barley, rye or wheat has been shown to accelerate the total gastrointestinal tract transit time in chickens Jeroch et al., 1990 Salih et al., 1991 Almirall and Esteve-Garcia, 1994 D nicke et al, 1997a and in turkeys Gro er and Jeroch, 1997 , which in turn suggests that an increased intestinal viscosity would result in the opposite effect and would consequently reduce feed intake and performance. Table 9.2 summarizes some results on measurement of...

Bile salt availability

Bile salt availability in young broilers plays a central role in determining the extent to which fats differ in their digestibility. It has been suggested frequently that bile availability in the very young chick is insufficient, particularly if high proportions of tallow are provided as dietary fat. It was demonstrated that addition of bile or several bile salts to broiler diets containing beef tallow resulted in an improvement in fat digestibility Fedde et al., 1960 Gomez and Polin, 1976...