Integrated multi-omics reveals the relationship between growth performance,rumen microbes and metabolic status of Hu sheep with different residual feed intakes

Residual feed intake(RFI)is a metric that provides a more accurate measure of feed efficiency.The lower the RFI,the higher the feed efficiency.The changes in the host microbiome and metabolome contribute to the greater feed efficiency of low RFI(LRFI)animals.The aim of this study was to explore the differences in rumen microorganisms,rumen metabolites and plasma metabolites of Hu sheep with differing RFI through the microbiome and metabolome.A total of 80 Hu sheep were used.The experiment consisted of a 15-d pretrial period and a 128-d experimental period.The RFI in the experimental period was calculated for all sheep,and the sheep were screened into high RFI(HRFI,n=8)and LRFI(n=8)groups.The HRFI and LRFI sheep did not differ in their initial and final body weights,average daily gain and body measurements,but the dry matter intake of LRFI sheep was significantly decreased(28.4%,P<0.001).The sheep with LRFI had higher digestibility of crude protein(P=0.010)and ether extract(P=0.010)compared to HRFI group.The concentrations of acetate(P=0.036),propionate(P=0.010),valerate(P=0.027)and total volatile fatty acids(P=0.048)in rumen of LRFI group were higher compared to HRFI group.The results of 16S rDNA sequencing indicated that the sheep with LRFI had higher proportions of Prevotella genus in rumen liquid(P=0.031).The rumen metabolome and plasma metabolome results showed that the citrate cycle,pyruvate metabolism and alanine,aspartate and glutamate metabolism processes were more active for sheep in LRFI group,which provided more energy substrate such as malic acid,oxoglutaric acid and citric acid.In conclusion,sheep with LRFI can utilize feed more efficiently,and the more active energy metabolism pathway and the production of energy substances may account for the higher feed efficiency.

The optical and molecular signatures of DOM under the eutrophication status in a shallow,semi-enclosed coastal bay in southeast China

We applied stable carbon isotopes,ultraviolet-visible absorption(UV-Vis),fluorescence excitation-emission matrices spectroscopy(EEMs),and Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS)to investigate the chemical composition and sources of the dissolved organic matter(DOM)in both the water column and pore water in Xiangshan Bay,a representative semi-enclosed and eutrophic bay in Zhejiang Province,China.One protein-like fluorescent component(C1)and two humic-like fluorescent components(C2 and C3)were identified by PARAFAC modeling.The concentration of dissolved organic carbon(DOC),the relative intensities of C2,C3,and black carbon-like compounds are all negatively correlated with salinity,indicating that there is a dilution effect of terrestrial signals by seawater in Xiangshan Bay.The differences in light penetration ability of Xiangshan Bay cause different degrees of photo-degradation,which may play an important role in the transformation of organic matter in Xiangshan Bay.The weak correlation between the C1 fluorescent component and salinity indicates that autochthonous sources cannot dominate the protein-like FDOM in the Xiangshan Bay drainage area.Multiple sources(such as anthropogenic inputs and release of pore water)also affect the distribution of the protein-like fluorescent component under eutrophication conditions.The relative proportion of the protein-like fluorescent component in Xiangshan Bay is on a medium level in China and anthropogenic inputs may be a significant source of DOM in coastal bays.

Habitat Influence on the Molecular, Carbon and Hydrogen Isotope Compositions of Leaf Wax n-Alkanes in a Subalpine Basin, Central China

Epidermal leaf waxes of terrestrial higher plants have been widely utilized for the reconstructions of paleoenvironment and paleoclimate in peat deposits. In this study, specimens of four plant species growing in both peatland and non-peatland habitats were retrieved to compare their molecular, carbon(δ13 C) and hydrogen(δ2 H) isotopic compositions of leaf wax n-alkanes from a closed subalpine basin in Central China. Three of the four species show quite higher total concentrations of n-alkanes in the relatively dry non-peatland setting than in the peatland. In addition, the δ2 H values of long-chain n-alkanes are generally less depleted in the peatland and are comparable among different plant species, which is interpreted as the influence of inundation condition and the possible limited supply of photosynthetic products. This study reveals different patterns of plant wax molecular and isotopic compositions between peatland and the surrounding non-peatland conditions, and confirms the paleoenvironmental potential of leaf wax ratios on the peat sequences.