Effects of almond hulls on the chemical composition and in vitro ruminal protein degradation of lucerne silage

Enhancing protein efficiency in the diet or the use of by-products can reduce feed costs and the environmental impact of animal production. Aims. The aim of this study was to determine the effects of almond hull (AH) additions to lucerne silage (alfalfa silage) on some chemical parameters and in vitro protein degradability. Methods. The second-cut lucerne was chopped after withering to up to 2 cm length. Chopped feed was ensiled with 100 g kg−1 DM of three varieties (Nonpareil, Ferragnes and Texas) of AHs dried and ground and each treatment was ensiled in vacuum-sealed polyethylene plastic bag for 90 days, as five replications. Key results. As a result, all AH treatments increased the dry matter of lucerne silage. Condensed tannin content in lucerne silage increased with addition of all AH varieties (P < 0.05). Catechin, which was high before ensiling in all AH groups, decreased after ensiling. Gallic acid content increased in all AH-supplemented groups (P < 0.05). In lucerne silage, NH3-N concentration decreased in all AH-supplemented groups, and in vitro ruminal undegradable protein was increased (P < 0.05). In the study, Fourier transform infrared spectra supported the findings, showing that chemical bonds were formed between tannins and proteins. Conclusions. As a result, it was shown that the addition of AH to lucerne silage could reduce ruminal protein degradability. Implications. This study offers strategies for converting AHs into a higher-value product and for enhancing the utilization of lucerne protein.