Chitosan affects total nutrient digestion and ruminal fermentation in Nellore steers

• Chitosan is a potential modulator of ruminal fermentation.
• Ruminal dosing of chitosan improved the nutrient digestibility.
• Chitosan had no effect on dry matter intake.

This study aimed to investigate the effects of chitosan on dry matter intake (DMI), nutrient digestibility, ruminal fermentation, and blood metabolites in Nellore steers. Eight ruminally cannulated Nellore steers (540 ± 28.5 kg of BW) were used in a replicated 4 × 4 Latin square design, with 21-d of experimental periods. The animals were randomly assigned to the following treatments: control (without chitosan addition; Q0), Q50, Q100 and Q150, by dosing 50, 100 and 150 mg/kg BW chitosan, respectively, through the cannula. Although there was no difference on DMI, chitosan addition increased dry matter, neutral detergent fiber, and crude protein apparent total-tract digestibility (P < 0.05). Ruminal pH was not affected, whereas NH3N concentration was quadratically affected with chitosan addition (P = 0.01). There were no differences in total volatile fatty acids concentration among treatments. Chitosan had a quadratic effect on propionate and butyrate, whereas acetate molar proportions decreased linearly (P < 0.05). Acetate:propionate ratio decreased with chitosan addition (P < 0.05). Plasma glucose concentration was higher with chitosan addition (P < 0.05); however, total protein, urea, aspartate aminotransferase, and gamma-glutamyl transferase were not affected by chitosan. Addition of chitosan altered ruminal fermentation, improved nutrient digestibility, and did not appear to damage animal health.