Retrograde flow of urine from cloaca to caeca in laying hens in relation to different levels of nitrogen intake.

Retrograde flow of urine into the caeca provides a more efficient recovery of nutrients and supplies a nitrogen source for the caecal microbes. 30 laying hens of Leghorn type were used in the present experiments. Hens were randomly divided into three treatment groups and fed a high nitrogen (19.8% crude protein in dry matter), medium (15.0% crude protein in dry matter), or low (10.6% crude protein in dry matter) isocaloric diet for fourteen days prior to and during the experimental period (8 h). Results from the study show that the retrograde flow of urine from cloaca to caeca is significantly higher in birds given a low protein diet compared to medium or high levels. It also shows that the produced amount of urine is significantly higher in hens given a low protein diet compared to the medium level diet.