A study on the nutritive value of pollen from the Chinese Masson Pine (Pinus massoniana) and its effect on fecal characteristics in rats

A digestion experiment with growing rats was conducted to study the effect of native and broken pollen of Chinese Masson Pine (Pinus massoniana) on fecal composition and digestibilities of dry matter, crude protein and crude ash. For that issue each 10 of 30 animals were fed a semisynthetic diet containing either no pollen or an addition of 6% native or broken pollen for 17 days at restricted amounts. In a second experiment each 6 of 12 growing rats received a semisynthetic diet containing either no or 5% broken pollen. At day 4, 11 and 18 samples of the feces were collected and analyzed for mesophilic aerobic bacteria. The pollen contained large amounts of cell wall constituents (26-30% lignin and 10-15% cellulose, 2-13% hemicellulose) with higher values found in native pollen. The contents of crude protein, crude fat, total lipids, available carbohydrates (starch and sugars), crude ash, gross energy and metabolizable energy were 13%, 2-10%, 8-10%, 17-18%, 3.1-3.5%, 21-22 kJ/g and 5.7-9.0 kJ/g. The addition of native pollen to the diet increased the total amount of feces by 71% as compared to the control level. The fecal contents of dry matter and of crude protein and crude ash in fecal dry matter changed by -5, +4 and -5 percentage units. The apparent digestibilities of dry matter and crude protein decreased by 3 and 5 percentage units, respectively, while the apparent digestibility of crude ash remained unchanged. Broken pollen acted in the same direction, however the effects were about 20% less pronounced as compared to native pollen. The pollen feeding reduced the fecal germ contents of Proteus mirabilis and Escherichia coli, while the amounts of alpha-hemolysing streptococci was increased. In total, the observed effects of an addition of native broken or pollen to the diet seemed to be based mainly on the increased intake of cell wall constituents.