Comparative digestive function and starch digestion kinetics in broilers and pigs

Abstract

This study compared starch digestion dynamics in broilers and pigs. Seven replicates of two broilers (24-d-old) and one pig (50-d-old) each were fed the same maize-based pelleted diet for 10 d, containing both solid (TiO ₂ ) and liquid (Cr-EDTA) markers. After 5 h of fasting, animals had 1 h of feed access before being euthanised at 2, 4, 6 and 8 h post-feeding. Digesta was collected from all pre-caecal segments. Jejunum and ileum combined were cut into four equal parts (SI1–4). Broilers had a heavier anterior tract and longer small intestine (SI) relative to live weight ( P < 0·05), lower gizzard pH than the pig stomach ( P < 0·05) and higher digesta DM. Duodenal digesta of broilers had a greater volume of particles <0·2 mm than pigs ( P < 0·05). Apparent starch digestibility was higher in SI1–SI3 of broilers ( P < 0·05), indicating more rapid starch digestion than pigs, although both species achieved similar digestibility (about 0·98) in SI4. Marker passage was unaffected by marker type but differed between species. Pigs showed higher proportion of markers exiting the anterior tract at 8 h ( P < 0·05) and tended ( P < 0·1) to have greater passage out of the SI, suggesting a more continuous flow pattern than broilers. Interval-based analysis showed similar marker passage out of the SI during 0–2 h, after which broilers had a pulsatile pattern, with reduced passage from 2 to 4 h, increased passage from 4 to 6 h and again lower passage from 6to 8 h ( P < 0·05). In conclusion, broilers and pigs can attain comparable starch digestibility but rely on different kinetics and physiological mechanisms.