Oxygen concentration of gut luminal contents varies post‐prandially in growing pigs
2022
Montoya, Carlos A. | Maier, Eva | Banic, Milena | McNabb, Warren C. | Moughan, P. J. (Paul J.)
The oxygen (O₂) concentration of gastrointestinal tract (GIT) contents decreases distally, but little is known about how O₂ concentrations are influenced by ingestion of a meal. The O₂ concentration in luminal contents at different GIT locations (stomach [cardia and pylorus], proximal, mid‐ and distal small intestine and caecum) and how these concentrations changed post‐prandially were determined. Fifty entire male pigs (22 kg bodyweight at the start of study) were fed semi‐synthetic diets containing casein, α‐lactalbumin, whey protein isolate or zein as the sole source of protein for 8 days. A further group of pigs received the casein diet for six days and a semi‐synthetic protein‐free diet for a further 2 days. On day 8, pigs (n = 2 per diet and time point) were euthanized post‐prandially (0, 1, 2, 4 and 6 h), and the stomach, small intestine and caecum were isolated and O₂ determined in the GIT contents. Observations at each time point were averaged across the diets (n = 10). The mean O₂ concentration was markedly higher (p ≤ 0.05) in the stomach compared with the rest of the GIT. The O₂ concentration was similar in the small intestinal regions (p > 0.05; 1.0%–1.1%) and the caecum (0.9%), apart for the proximal small intestine which had a 24% higher (p ≤ 0.05) O₂ concentration than the caecum. The mean O₂ concentration in the GIT varied post‐prandially (p ≤ 0.05). The O₂ concentration in the cardia decreased 1.8%/h over the first two hours post‐feeding and thereafter increased 0.3%/h (p ≤ 0.05). In the caecum, the O₂ concentration was constant during the first 4 h and thereafter increased slightly (p ≤ 0.05). The flow of food through the GIT influenced both the concentration and amount of O₂ in GIT luminal contents.
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