Targeted metabolomics analysis of fatty acids in lamb meat for the authentication of paper mulberry silage as a substitute for alfalfa silage

The paper mulberry (Broussonetia papyrifera L.) is a valuable source of woody forage that can be used for ruminants, such as goat and lambs. However, there is limited knowledge about how paper mulberry silage affects carcass characteristics, meat physicochemical attributes, amino acid and unsaturated fatty acids in Hu lambs compared to alfalfa silage. The objective of this experiment was to investigate the impact of substituting alfalfa silage with paper mulberry silage on the slaughter performance, meat quality, free amino acid and fatty acid composition in muscles of Hu lambs.

Thirty 60-day-old male Hu lambs with 17.13 ± 0.26 kg body weight were randomly allocated into paper mulberry silage (30% of total mixed ration) and alfalfa silage (30% of total mixed ration) treatment, and the feeding trial lasted 70 days. The results indicated no significant differences in all measurements (P > 0.05). However, compared to the group fed with alfalfa silage, the group fed with paper mulberry silage exhibited a reduction in meat drip loss (P < 0.05) without any notable effect on meat nutrients (P > 0.05). Targeted metabolomics analysis revealed that feeding paper mulberry silage led to decreased levels of certain bitter amino acids, such as valine, leucine, isoleucine, tryptophan, and phenylalanine (P < 0.05). Furthermore, the consumption of paper mulberry silage significantly augmented the levels of monounsaturated and polyunsaturated fatty acids, particularly n6-polyunsaturated fatty acids (C18:2n6, C20:3n6, C20:4n6, etc.), in meat.

Substituting paper mulberry silage for alfalfa in the daily diet of Hu lambs not only has no detrimental effect on animal performance but also improves meat unsaturated fatty acid composition.