a1 INRA, UMR 1079 SENAH, F-35590 St-Gilles, France
a2 Prairie Swine Centre, 2105 8th Street East, Saskatoon, SK, Canada, S7H 5N9
a3 Centro Internacional de Agricultura Tropical, AA 6713 Cali, Colombia
a4 INSERM UMR 865, CNRS, Faculté R. Laennec, IFR62 Lyon Est, Université Claude Bernard Lyon 1, Lyon, France
Dietary protein might modulate mucin flow and intestinal mucin gene expression. Since unheated phaseolin from Phaseolus vulgaris bean is resistant to digestion and increases gut endogenous protein losses, we hypothesised that unheated phaseolin influences mucin flow and gene expression, and that phaseolin heat treatment reverses these effects. The hypothesis was tested using a control diet containing casein as the sole protein source and three other diets with casein being replaced by 33 and 67 % of unheated and 67 % of heated phaseolin. The rats were fed for 6 d and euthanised. Digesta and faeces were collected for determining digestibility and mucin flow. Gut tissues were collected for mucin (Muc1, Muc2, Muc3 and Muc4) and Trefoil factor 3 (Tff3) gene expressions. Colonic mucin flow decreased linearly with increasing the dietary level of unheated phaseolin (P < 0·05). Unheated phaseolin increased N flow in ileum, colon and faeces (P < 0·05), and reduced apparent N digestibility linearly (P < 0·01). Heat treatment reversed all these changes (P < 0·05 to < 0·001), except mucin flow. The expressions of Muc mRNA in gut tissues were influenced by dietary phaseolin level (ileum and colon: Muc3 and Muc4) and thermal treatment (ileum: Muc2; colon: Muc2, Muc3, Muc4 and Tff3) (P < 0·05 to 0·001). In conclusion, phaseolin modulates mucin flow and Muc gene expression along the intestines differentially.
(Received January 05 2010)
(Revised April 19 2010)
(Accepted June 14 2010)
(Online publication August 02 2010)
p1 Present address: Riddet Institute, Private Bag 11 222, Palmerston North 4442, New Zealand.
Abbreviations: P0, casein control diet (no phaseolin); P33, diet containing phaseolin at 330 g/kg total protein; P67, diet containing phaseolin at 670 g/kg total protein; P67-H, diet containing heat-treated phaseolin at 670 g/kg total protein; Tff3, trefoil factor 3