Kinetics of cecal gas production and in vitro digestibility of cereals used in swine feed

Cecal fermentation is a key process for the energetic utilization of undigested carbohydrates in pigs, directly influencing intestinal health, nutrient efficiency, and overall productive sustainability. However, the fermentation dynamics of different cereals and plantbased byproducts remain poorly characterized. The aim of this study was to evaluate the in vitro digestibility and cecal gas production kinetics of three conventional cereals (corn, wheat, and barley) and two comparative feedstuffs (Dominican banana and cereal straw) commonly used in swine diets. A multienzymatic in vitro procedure simulating gastric, intestinal, and cecal fermentation phases was applied, with gas measurements taken at 2 to 96 h intervals. Results showed that cereals presented higher total dry matter digestibility (85.7 %) compared to banana and straw (54.4 %; P < 0.001), associated with lower neutral detergent fiber (15.4 %), acid detergent fiber (4.6 %), and lignin (1.22 %) contents. Fermentation kinetics revealed that cereals and banana displayed a rapid initial gas production (65 mL/g DM at 24 h) with sustained increases up to 96 h (90 mL/g DM), whereas cereal straw showed the slowest fermentation rate and no defined plateau (50 mL/g DM). This pattern reflects the differential availability of fermentable fractions and the structural influence of fiber on cecal microbial activity. Overall, the results confirm that the chemical composition and structural nature of feed ingredients determine the efficiency of cecal fermentation, highlighting the importance of fiber quality and type as key factors in diet formulation aimed at maximizing digestibility and energetic utilization in pigs.