Activities of enzymes of the pancreas, and the lumen and mucosa of the small intestine in growing broiler cockerels fed on tannin-containing diets

Abstract

Diets containing vegetable tannins, predominantly hydrolysable gallotannins, at levels of 13.5, 25 and 50 g/kg were fed to growing broiler cockerels to examine their effect on enzymes in the pancreas, the intestinal lumen and the intestinal mucosa. Pancreas weight per unit live weight showed a significant (P < 0.05) increase with increasing level of dietary tannin while that of the liver remained unaffected. Trypsin (EC 3 . 4 . 2 1 .4) and a-amylase (EC 3.2.1.1) activities in the pancreas of birds fed at the highest level of tannins were more than double those from birds fed on a tannin-free control diet. In the intestinal lumen inhibition of trypsin activity increased with increasing level of dietary tannin; a-amylase activity was inhibited at intermediate tannin levels but was restored at the highest level. Dipeptidase (EC 3.4.13.11) and sucrose a-glucosidase (disaccharidase) (EC 3.2.1.48) in the intestinal mucosa were both inhibited by tannins. Growth of the birds and digestibility of nitrogen were adversely affected by the tannin-containing diets.Tannin : Pancreatic enzymes : Brush border enzymes : Cockerel It is well established that tannins are potential protein precipitants (Hagerman & Butler, 1980;Hagerman & Klucher, 1986; Makker et al. 1987) and that they reduce the digestibilities of proteins (Mohammed & Ahnied, 1987) when present in animal feeds. Elevated faecal nitrogen excretion associated with ingestion of tannin-containing feeds is ascribed largely to interactions between either tannins and dietary protein or tannins and digestive enzymes, or both. However, Mitjavilla et al. (1977) concluded that the excess faecal N is mostly a result of mucus hypersecretion.Studies in vitro (Griffiths, 1981 ;Lumen & Salamat, 1980;Horigome et al. 1988) and in vivo (Griffiths & Moseley, 1980; Horigome er al. 1988) have demonstrated the formation of tannin-enzyme complexes. However, adopting a technique in vitro more relevant to the situation in vivo, Mole & Waterman (1987) showed that trypsin retained all its activity in the presence of tannic acid when the system included a substrate protein (bovine serum albumin ; BSA) and glycocholic acid, indicating that under such conditions tannins have a preferential affinity for dietary protein over enzyme protein. In previous work Mole & Waterman (1985) had shown that the formation of complexes between tannins and BSA, used as a substrate for proteolysis, could result in either enhancement or inhibition of proteolysis, or no effect at all depending on the tannin:BSA ratio in the complex.In contrast to what had been reported with rats (Griffiths & Moseley, 1980; Horigome et ul. 1988), tannins were shown to exert no effect on protein digestion by insect herbivores (Martin et ul. 1985(Martin et ul. , 1987 in terms of changes in activities of enzymes in the lumen of the small intestine, in order to provide further insight into the mode of action of dietary tannins. A further aim was to examine the effect of dietary tannins on the activity of membrane-bound enzymes wh...

Dietary utilisation of protein and energy from fresh and ensiled coffee pulp by the Nile tilapia, Oreochromis niloticus

“…This might be sufficient to interact with protein of coffee pulp and should be not enough to complex those from other ingredients, considering the previous described 1:2 optimum polyphenol/protein ratio. Significant inhibition of trypsin from intestinal lumen and dipeptidase for intestinal mucosa have been observed on broiler cockerel with a tannin incorporation level of 13.5 g kg -1 food dry matter (Ahmed et al, 1991). Considering tannin level given for coffee pulp, amount of coffee pulp used in our experiment could be sufficient to induce such inhibition.…”

Potential of oak acorn with and without polyethylene glycol as an alternative to corn in broiler diets

“…Also in the current study, pancreas weight was not affected by OA, which is in line with other studies (Longstuff & Mc Nab, 1991;Nyacotti et al, 1996). Conversely, in some previous studies (Ahmed et al, 1991;Mahmood et al, 2008), pancreatic hypertrophy was observed in broilers given high-tannin diets. Because pancreatic enzymes are inhibited by tannins, their production would be increased by the pancreas.…”

“…Because pancreatic enzymes are inhibited by tannins, their production would be increased by the pancreas. This condition could increase the weight of the pancreas (Ahmed et al, 1991). Birds response to dietary tannins is influenced by factors such as the source of the tannins and feedstuffs, tannin concentration, animal species, age and production level, the response parameters (weight gain, feed intake and feed efficiency), length of the test period, and diet composition (level and source of protein) (Jansman, 1993).…”

The effect of lingonberry leaves and oak cortex addition to sheep diets on pancreatic enzymes activity

“…Furthermore, such findings were obtained in monogastric animals. Ahmed et al (1991) reported that feeding growing broiler cockerels diet with increasing level of tannins, significantly increased weight of pancreas in comparison to control birds. It was probably because of higher activities of trypsin and α-amylase.…”