Effect of indigestible polysaccharides on protein digestibility and nitrogen retention in growing rats.
The effect of five indigestible polysaccharides (IP) of different origin and chemical structure on N balance and dry matter digestibility was studied in growing rats. The diets contained 10% of gum guar (GG), carob bean gum (CBG), Na-alginate (Na-A), agar-agar (AA) or carrageenan (C), respectively. Dry matter digestibility and apparent protein digestibility were significantly decreased below control values by all 5 IP. N retention was significantly lower after ingestion of AA or C. In the rats receiving GG, CBG or Na-A urinary N excretion was reduced, thus compensating for increased fecal N losses by these animals. The different effects of the 5 substances on N balance are attributed to their partial breakdown through the action of intestinal microflora and/or their ability to partially inhibit the activity of proteolytic enzymes in the gastrointestinal tract. Trypsin inhibition in vitro was observed for C only. Suitability of the various IP as bulking agents in reducing diets is discussed.
D000362:Agar / Q000494:pharmacology; D000464:Alginates / Q000494:pharmacology; D000818:Animals; D002351:Carrageenan / Q000494:pharmacology; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000494:pharmacology*; D004044:Dietary Proteins / Q000008:administration & dosage / Q000378:metabolism*; D005243:Feces / Q000032:analysis; D008297:Male; D009584:Nitrogen / Q000032:analysis / Q000378:metabolism*; D011134:Polysaccharides / Q000008:administration & dosage / Q000494:pharmacology*; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D014361:Trypsin Inhibitors / Q000378:metabolism; D014886:Weaning
D000464:Alginates; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D011134:Polysaccharides; D011506:Proteins; D014361:Trypsin Inhibitors; D002351:Carrageenan; D000362:Agar; D009584:Nitrogen