# Effects of Different Levels of Lycium ruthenicum Leaves on Rumen Fermentation, Amino Acids, Fatty Acids and Rumen Bacterial Diversity in Sheep

## TL;DR

Adding Lycium ruthenicum leaves to sheep diets improves rumen health and meat quality by altering fermentation and bacterial diversity.

## Contribution

This study demonstrates the novel use of Lycium ruthenicum leaves as a feed supplement to enhance sheep meat quality and rumen function.

## Key findings

- Supplementing sheep diets with 5–15% Lycium ruthenicum leaves increased rumen acetate, butyrate, and total volatile fatty acids.
- Lycium ruthenicum leaves altered rumen bacterial diversity, increasing Firmicutes and Ruminococcus while decreasing Prevotella.
- Meat from supplemented sheep had improved color, higher sweet amino acids, and favorable fatty acid changes.

## Abstract

Lycium ruthenicum (black goji berry) leaves (LRL) contain a variety of bioactive compounds such as flavonoids, polyphenols, alkaloids, etc., which make it a good candidate for improving the growth performance of livestock and the quality of their products. Lycium ruthenicum extracts given to ruminants like sheep have been shown to enhance antioxidant and immune activity and improve ruminal fermentation. However, feeding LRL to ruminants has rarely been reported. In this study, we compared the ruminal microbes, fermentation, and meat quality of F1 generation crosses of Dorper × Hu lambs supplemented with different levels of LRL during the finishing stage. The addition of 5–15% LRL to the sheep diet improved the rumen microbial community, its fermentation activity, and the resulting meat quality.

Lycium ruthenicum leaves (LRL), as an agricultural by-product rich in bioactive compounds, can be used as an unconventional feedstuff in animal diets and have the potential to improve animal health. This study investigates the effects of dietary supplementation with graded levels of LRL on rumen fermentation, meat amino acid and fatty acid profiles, and rumen bacterial diversity in sheep. Forty three-month-old male Dorper × Hu crossbred F1 lambs with an initial body weight of 29.58 ± 2.06 kg were randomly assigned to four groups (n = 10). Over a continuous 63-day trial period, the lambs were fed diets containing 0%, 5%, 10%, and 15% LRL, respectively. At the end of the trial, rumen fluid and longissimus dorsi muscle samples were collected to assess rumen fermentation characteristics, bacterial community structure, and meat quality. The results showed that: (1) The concentrations of acetate, butyrate, and total volatile fatty acids (TVFA) in the rumen were increased in the LRL5% group (p < 0.05 or p < 0.01). (2) The relative abundance of the phylum Firmicutes and the genus Ruminococcus increased (p < 0.05), while the relative abundance of the genus Prevotella decreased (p < 0.05) in the LRL5% group. (3) Meat L* increased (p < 0.05), and a* decreased (p < 0.05) in the LRL-supplemented groups. (4) The content of sweet amino acids in meat increased in LRL groups (p < 0.05). Moreover, the contents of non-essential amino acids, sweet amino acids, and total amino acids in meat increased linearly with increasing dietary LRL levels (p < 0.05). (5) Compared with the CON group, the content of C18:0 in meat decreased in the LRL5% group (p < 0.05), while the content of C20:1 increased in the LRL10% group (p < 0.05). In conclusion, dietary supplementation with LRL can improve meat quality, rumen fermentation, and rumen bacterial community structure in sheep. The recommended dietary inclusion level of LRL ranges from 5% to 15%.