Shrimp shell chitosan improves preservation quality and in vitro rumen digestibility and reduces methane...

Objectives: This research assessed the impact of additives derived from shrimp shells, specifically chitosan, on the preservation of total mixed rations (TMR) in both anaerobic and aerobic environments, along with their effects on in vitro rumen digestibility, fermentation attributes, and methane production. Materials and Methods: A 2 × 4 factorial randomized complete block design was employed, featuring five replications. The study included two preservation conditions (anaerobic and aerobic) and four additive treatments: control, shrimp shell, chitin, and chitosan at 1% of fresh matter. After 30 days of storage, we assessed the preservation characteristics and the in vitro rumen fermentation variables. Results: Anaerobic preservation led to decreased dry matter loss, pH, and NH₃, and to increased total volatile fatty acids compared with aerobic preservation (p < 0.01). Chitosan showed the most beneficial preservation effect, exhibiting the least dry matter loss (3.50%) and pH (5.20), along with the highest organoleptic quality. Significant interactions between treatment and additive were observed for traits related to preservation, suggesting that the positive effects of chitosan were more pronounced under anaerobic conditions. Additionally, chitosan achieved the highest in vitro dry matter and organic matter digestibility (56.61% and 58.30%, respectively), along with the lowest methane concentration and cumulative gas production (p < 0.05). Conclusions: Shrimp shell-derived chitosan at 1% fresh matter effectively enhances TMR preservation and improves rumen fermentation, thereby increasing digestibility and reducing methane concentration. This indicates the potential to use shrimp shell waste as a valuable feed additive, promoting sustainable ruminant feeding and supporting circular economy practices.