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Sudan Journal of Agricultural Research

Evidence of the presence of tannin-enzyme complexes in the gut of chicken fed dietary tannins
 

E. Ahmed and R.R. Smithard
 

Abstract:

Activity of pancreatic, intestinal lumen and mucosa enzymes were measured in chicken fed different levels (0, 13.5, 25.4 and 51 g/kg diet) of dietary tannins for 4 wk, ad-libitum. Feed intake, body weight gain and efficiency of feed conversion were all depressed by tannins. An improvement was noted in efficicency of feed conversion in birds fed the highest level of tannins from wk 1 to 4. All luminal enzymes activities were inhibited by tannins; however, a significant recovery was obtained when polyvinylpyrrolidone (PVP) was added to homogenization media. The highest rate of recovery was found for chymotrypsin (EC 3.4.21.1) and the lowest was for α-amylase (EC 3.2.1.1). Addition of exogenous trypsin and enteropeptidase to enzyme homogenates increased tryptic and chymotryptic activity by 105o and 72% of the original activity, repectively. Tannins induced a significant (P<0.05) increase in the relative weight of pancreata; however, that of the liver was only enlarged in birds that consumed the highest level of tannins (51 g/kg diet). Pancreata from birds fed the highest level of tannins accumulated more tryptic activity compared to chymotryptic and α-amylolytic. The activity of mucosal enteropeptidase (EC 3.4.21.9) was enhanced and that of dipeptidase (EC 3.4.13.11; L-leucylglycine substrate) was inhibited. There was no clear effect of tannins on disaccharidases (sucrase; EC 3.2.1.48; maltase; EC 3.2.1.20) activity.

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Sudan Journal of Agricultural Research Vol. 4(2004) PP. 77-87