From the perspective of genomics and metabolomics, revealing the effects of feeding methods on Jersey cattle on the Qinghai-Tibet Plateau

Abstract Background: Grazing and house feeding methods have been studied on yak, but there is no relevant research on grazing and indoor feeding of Jersey cattle on the Qinghai-Tibet Plateau.Results: In this study, the differences in metabolites in the serum and rumen of Tibet Plateau Jersey cattle in total mixed ration house feeding and grazing supplementary feeding were assessed. The rumen fermentation parameters, bacterial community, serum antioxidant indices, immune indices and metabolites of total mixed rations house-feeding Jersey cattle (Group B, n =6) and grazing supplementary-feeding Jersey cattle (Group G, n =6) were evaluated. The rumen fermentation parameters results showed that the acetic acid and propionic acid concentrations and the ammonia nitrogen concentration in Group B were significantly higher than those in Group G (P < 0.05). The rumen bacterial community 16S rDNA gene results showed that The Chao1 index was significantly higher in Group G than in Group B (P < 0.05), and the observed_species, Shannon and Simpson indices were not significantly different between the two groups (P > 0.05). The distance between the two groups by principal component analysis was not significant, and adnoism analysis showed that there was no significant difference in rumen flora between Group G and Group B (R=0.55, P=0.08). Antioxidant and immune indices analysis of serum results showed that there was no significant difference in total antioxidant capacity between Group G and Group B (P > 0.05), while IL-6, Ig-M and TNF-α were significantly higher in Group G than in Group B (P < 0.05). LC‒MS metabolomics analysis of serum results showed that, A total of 149 major serum differential metabolites were identified between Group G and Group B. The differential metabolites were mainly enriched in the metabolic pathways of biosynthesis of amino acids, protein digestion and absorption, ABC transporters, aminoacyl-tRNA biosynthesis, mineral absorption and biosynthesis of unsaturated fatty acids and other metabolic pathways.Conclusions: The results of this study revealed the differences in rumen fermentation and serum metabolism of Jersey cattle under different feeding methods, providing a theoretical basis for the scientific feeding of Tibetan Plateau Jersey cattle.