Effect of Natural Carbohydrate Fraction from Yeast Cell Wall (NCF) and Age on Intestinal Morphometric Parameters of Broiler Chickens

Yeast cell wall products are used as feed supplements for increasing animal health and performance. A trial was set up to test effects of natural carbohydrate fraction from yeast cell wall (NCF) on gut parameters that can be correlated with gut health. Trial design included four treatments (control group and three groups with different levels of NCF in feed: 0.02%, 0.04% and 0.08%) and eight replications per treatment. Each replication was one pen with 38 broiler chicks. Chicks were sexed in incubation station and only males were used in the trial. On days 7 and 28 of the trial, after body weight had been measured, chicks with weight approximate to that of their treatment average were selected for intestinal sampling. Ten chicks per treatment were slaughtered. Central part of jejunum was fixed, sectioned and stained with double staining (Alcian Blue and Periodic Acid-Schiff). At least 15 measurements (25 on average) were made per bird for villus height and width, crypt depth and Tunica muscularis thickness. Statistical analysis was performed using factorial ANOVA test with feed and age as factors, and with Duncans’ test. Age significantly affected jejunal morphometry, while effects of NCF were less obvious. Villus height, crypt depth and Tunica muscularis thickness doubled from 7th to 28th day, leaving villus to crypt ratio unchanged. Villus width also increased, but to a lesser extent, making villi of older chicks more elongated. Group receiving 0.02% NCF in feed had smaller crypt depth, and larger villus to crypt ratio, while group receiving 0.08% NCF had smaller villus area (villus height × villus width) compared to the control group.