Effects of dietary pectin on protein digestion and metabolism in growing rats

In an attempt to clarify the relationships between the digestive and metabolic effects of additional feeding of citrus pectin, the intestinal contents, tissues weights, nitrogen excretion and retention were studied in laboratory rats. Twenty-four growing male Wistar rats (98.8 g ± 5.3 g of body weight) were fed ad libitum for 20 days with balanced diets containing casein as the source of protein. In the experimental diet 96 g of wheat starch was replaced by 80 g of citrus pectin and 16 g of vegetable oil. Apparent digestibility and apparent protein biological value were calculated, the weights of digestive tissues and digestive organ content weights were also determined. All tissues of different parts of the digestive tract were heavier in the pectin fed group, and small intestine and caecum were statistically significant different as compared to control group. The contents of the small intestine and caecum were significant heavier in the pectin group. Pectin significantly lowered dry matter intake and growth rate and significantly increased faecal excretion of nitrogen and significantly decreased urinary nitrogen excretion. The consequence of alteration in the nitrogen excretion route was significantly lower apparent protein digestibility and apparent net protein utilisation, but apparent protein biological value was unchanged.