Evaluation of Beech Nuts, Shells, and Cores as Ruminant Feed Sources: Chemical Composition, in vitro Digestibility, Gas Production, and Methane Emissions

Abstract

This study investigated the chemical composition, in vitro gas production, methane emissions, and in vitro digestibility of whole beech nuts (WB), their shells (BS), and cores (BC) to evaluate their potential as feed ingredients for ruminants. Samples were analyzed for chemical composition and incubated using the in vitro gas production technique (Hohenheim) to assess fermentation kinetics, organic matter digestibility (OMD), metabolizable energy (ME), net energy lactation (NEL), in vitro true digestibility (IVTD), and methane production. The results showed significant differences           (P < .05) among the three nut parts. Beech nut cores had the highest crude protein (23.46%) and ether extract (19.93%) contents, with superior cumulative gas production (37.38 mL/200 mg DM at 96 hours) and a higher gas production rate, indicating their high fermentability. It also showed the highest OMD (62.82%), ME (12.29 kcal/kg DM), NEL (7.97 kcal/kg DM), and IVTD (95.82%). Furthermore, BC produced the lowest methane emission (2.30 mL), indicating its potential effectiveness in mitigating enteric methane production when incorporated into ruminant rations. Conversely, BS exhibited the highest fibre and lignin contents, which corresponded with the lowest values for total gas production (20.52 mL), OMD (32.25%), ME (4.53 kcal/kg DM), NEL (1.80 kcal/kg DM), and IVTD (36.32%). However, it produced the greatest methane yield relative to the total gas volume. Whole beech nuts showed moderate nutritive and fermentative values due to their mixed composition of cores and fibrous shells, while BC emerged as a high energy and protein feed promising sustainable ruminant nutrition and lower methane emissions. Meanwhile, BS have limited nutritive value but may serve as a source of structural fibre when used in small quantities. Further in vivo studies are recommended to confirm animal performance responses, palatability, and the practical inclusion levels of beech nuts and their parts in livestock diets.