Effect of dietary fiber, genetic strain and age on the digestive metabolism of broiler chickens

Krás, RVde M Kessler, ARibeiro, AMLHenn, JDBockor, LSbrissia, AF

In this study, 360 male broilers, out of which 240 of a fast-growing strain (Cobb500), and 120 of a slow-growing strain (Label Rouge), were used to evaluate the effect of dietary fiber on digesta transit time and digestive metabolism during the period of 1 to 42 days of age. A completely randomized experimental design with a 3x2 factorial arrangement was applied, consisting of three groups of birds (slow-growing - SG; fast-growing fed ad libitum - FGAL; and fast-growing pair-fed with SG broilers - FGPF) and two iso-protein diets (a 3100 kcal ME/kg low-fiber diet - LFD- and a 2800 kcal ME/kg high-fiber diet - HFD- with 14% wheat bran and 4% oat hulls). HFD-fed birds presented lower ME retention (p 0.001) and lower dry matter metabolizability (DMM) (p 0.001), which is possibly related to the shorter digesta transit time observed in these birds (p 0.001). DMM was reduced with age, whereas metabolizable energy remained almost constant (p 0.001) independently of strain. This may be related to the increase in feed intake as birds age. The slow-growing strain did not present better utilization of the high-fiber diet as compared to the fast-growing strain in none of the analyzed ages, even though showing a significant better use of fiber and dietary energy from 31 days of age.

1. pair-fed
2. fiber
3. metabolism
4. strain
5. Age