Samuel Oghenevwede MUKORO

This study evaluated the in vitro nutritive value of diets containing different inclusion levels of chitin and chitosan extracted from periwinkle shells (Tympanotonus fuscatus). The experiment aimed to determine the effects of these biopolymers on gas production, nutrient digestibility, and fermentation characteristics using in vitro rumen incubation techniques. Chitin and chitosan were extracted from processed periwinkle shells and incorporated into diets at varying levels (0.5–6%), alongside control and antibiotic-based treatments. Chemical composition analysis showed significant variations in crude fibre, ash, and protein content, with the 0.5% chitosan diet recording the highest crude protein (22.75%) and organic matter (91.00%). Gas production increased progressively with incubation time, peaking at 24 hours. Diets containing 0.5% chitosan produced the highest cumulative gas volume (30.00 ml/200 mg DM), indicating enhanced microbial fermentation, while higher chitin levels (6%) suppressed fermentation activity. Post-fermentation parameters showed that moderate chitosan inclusion (0.5%) improved dry matter digestibility (67.77%), organic matter digestibility (64.86%), metabolizable energy (7.58 MJ/kg DM), and short-chain fatty acid production (0.657 mmol/L) without significantly affecting methane output. Excessive inclusion levels reduced digestibility and fermentation efficiency