Abstract
BACKGROUND: The objective of this study was to examine the relationship between two different types of silage (saline; SQ and non-saline; NSQ) and rumen metabolism in Tibetan sheep. RESULTS: It was found that sheep in the saline silage (SQ group) exhibited superior apparent quality (e.g., crude protein, crude fat, DM, crude polysaccharide, polyphenols, and flavonoid), secondary metabolite profiles (e.g., Proline, Leucine, Alanine, Pyruvate), and fermentation microbial populations (e.g., Firmicutes, Bacteroidota, and Lactobacillus) compared to the non-saline (NSQ) silage group. However, the higher fiber and carbohydrate content in the SQ silage resulted in lower relative feed value (RFV) values, which was also responsible for the increased proportion of Rikenellaceae_RC9_gut_group in the rumen of the SA-1 group. The greater contents of amino acids and saccharides in the GQ silage were also responsible for the acceleration of the growth and metabolic processes of rumen microorganisms. Furthermore, the presence of phenolic compounds, glutamate, and lactic acid bacteria in the SQ silage may also have contributed to the consumption of histamine in the rumen, while the accumulation of phenolic compounds may have been responsible for the reduced contents of short-chain fatty acids in the rumen. Furthermore, a probable association between histamine decline and ATP accumulate was identified. CONCLUSIONS: In conclusion, metabolites and microorganisms enriched in saline silage exert a positive influence on the metabolites and microorganisms in the rumen of Tibetan sheep. Additionally, the accumulation of phenolic compounds, glutamate, and lactic acid bacteria in saline-alkali land silage may lead to the decrease of histamine in the rumen of Tibetan sheep and is also the cause of the decrease in short-chain fatty acid levels in the rumen. Video Abstract.