GROWTH OF THE DIGESTIVE ORGANS IN LIGHT AND HEAVY TYPES OF CHICKENS

The absolute and relative digestive organs (proventriculus, gizzard, l iver, small intestine, large intestine) in male light (Issa Brown) and heavy (Ross-1) types of chicken was estimated at two week intervals, from hatching to eight weeks of age. On the first day of age there wer e no statistically significant differences in organ dimensions between the two strains. The relative growth of digestive organs in both type s of chickens showed a rapid increase during the first two weeks and a fter that decreased. The growth rate in heavy type chicks was faster e specially during the first two weeks after hatching. From the second w eek of age (2, 4, 6 and 8 weeks) the dimensions of the digestive organ s were significant higher (P<0.01) in heavy type chickens. The proport ion of the body weight of the gizzard (6,10%), liver (3,20%), and smal l intestine (4.70%), al hatching, was higher in the light type of chic kens than in the heavy type (4.60%, 2,50% and 2,90% respectively). Aft er that the values were similar in both strains.