Growth Performance, Biochemical Blood Indices, and Large Intestine Physiology of Rats Fed Diets with Alfalfa Protein-Xanthophyll Concentrate

SIMPLE SUMMARY: Alfalfa protein-xantophyll concentrate is a rich source of nutrients and bioactive compounds. It provides protein, lutein, vitamins, minerals, phytoestrogens, and other plant metabolites. Thus, it may affect animal health in many ways; however, its impact is not fully recognized. Therefore, the aim of the study was to determine the effect of dietary supplementation with 1.5% and 3% concentrate on growth performance, blood biochemical profile, and large intestine physiology of rats as a model animals. The results showed that feeding a diet supplemented with alfalfa concentrate could reduce thickness of the protective mucus layer in the colon of rats but did not affect animal growth and microbial activity in the caecum. ABSTRACT: The effect of dietary levels of alfalfa protein-xanthophyll concentrate (PXC) was determined in growing rats. Three groups of eight four-week-old male Wistar rats, with an average initial body weight of 61 g, were fed for 28 days either natural-ingredient diets without PXC or supplemented with 1.5% or 3% PXC. Growth performance, blood biochemistry, caecal fermentation, morphology of the large intestine, and mucin gene expression were evaluated. PXC did not affect growth performance but tended to decrease relative liver weight. Among biochemical blood parameters, only bilirubin decreased and uric acid increased in response to 1.5% and 3% PXC, respectively. Caecal fermentation was not affected, with the exception of isovaleric acid concentration, which tended to be higher in rats fed the diet containing 3% PXC. Colonic crypts tended to be deeper in rats fed the 3% PXC diet and the thickness of the colonic mucus layer was reduced by both PXC levels. In conclusion, PXC did not affect growth performance or caecal fermentation but decreased thickness of the protective mucus layer in the colon.