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The grazing grassland ecosystem on the Qinghai-Tibetan Plateau is highly impacted by seasonal temperature variations. During the long cold season, the biomass and nutrient contents of forage grass do not meet the nutritional needs of grazing livestock and seriously affect growth performance and livestock products. This study investigated different feeding strategies on growth performance, meat quality and rumen fungal community of Tibetan sheep in the winter. Twelve one-year-old healthy castrated Tibetan sheep with similar initial body weights were randomly grouped into traditional grazing (TG) and barn feeding (BF) groups. The TG sheep were labelled and grazed on the local cool-season pasture without feed supplementing, while BF sheep were fed a mixed diet in feeding shed. Compared with the TG group, significantly increased body weight and average daily weight gain (ADG) were observed in the BF group (p < 0.001), which resulted in a significant increase in the hot carcase weight, net meat weight, carcase rate and net meat rate (p < 0.01). Moreover, the longissimus dorsi muscle of the BF group showed significantly increased muscle fibre diameter, perimeter, and area and increased crude protein and ether extract contents (p < 0.01), while the meat tenderness and amino acid content were reduced. ITS high-throughput sequencing showed that Ascomycota was the predominant fungal phylum in the rumen of Tibetan sheep. At the genus level, the rumen of TG sheep presented higher proportions of Preussia, Anaeromyces and Pilidium, while the most abundant genera in the BF sheep were Penicillium, Acaulium and Vishniacozyma. In summary, BF strategy enhanced the relative abundance of several dominant fungal genera related to the nutrient absorption and metabolism capacity, and effectively improves the growth and slaughter performance and affects meat quality of Tibetan sheep in the winter. Growth and slaughter performance effectively improved under the barn feeding (BF) strategy. The mutton of BF group had higher crude protein and ether extract contents, and lower amino acid content. Barn feeding strategy enhanced the rumen nutrient absorption and metabolism capacity by altering the relative abundance of several dominant fungal genera. [ABSTRACT FROM AUTHOR]

Simple Summary: The quality of mutton is closely related to the development of the entire animal husbandry and sheep industry. The present work quantified the difference in meat quality between Chaka (CK) sheep and (Tibetan) TB sheep through the technology of transcriptomics, combined with metabolomics, to identify genes and metabolites, which are related to meat quality. Our study found that TB sheep have better nutritional value, while CK sheep have better flavor. The GPAT2, PLPP2, AGPAT1, PNPLA2, and GPAT4 genes were identified as key genes that regulate glycerophospholipid metabolism and correlate with meat color, texture, and flavor. Our study comprehensively compared the longissimus thoracis et lumborum (LTL) muscle of CK sheep and TB sheep and explored the difference in meat quality at the molecular level, which may provide a strategy for improving meat quality from a molecular perspective. This study aimed to comprehensively evaluate the characteristics in the longissimus thoracis et lumborum (LTL) muscle of Chaka (CK) sheep and Tibetan (TB) sheep, and transcriptomics–metabolomics association analysis was used to find the possible genes, differential metabolites, and significant differential metabolic pathways that lead to meat quality differences. Based on the researched results, the nutritional quality of meat, including the contents of ether extract (11.95% vs. 10.56%), unsaturated fatty acid (51.20% vs. 47.69%), and polyunsaturated fatty acid (5.71% vs. 3.97%), were better in TB sheep than in CK sheep, while the CK sheep has better muscle fiber characteristics, such as the total number (62 vs. 45) and muscle fiber density (1426.54 mm2 vs. 1158.77 mm2) and flavor. Omics research has shown that the key differential metabolites and metabolic pathways were dominated by amino acid metabolism, particularly the glutathione metabolism, taurine and hypotaurine metabolism, and lipid metabolism-related pathways, such as glycerophospholipid metabolism and the sphingolipid signaling pathway. The intermediate metabolite sn-Glycerol 3-phosphoethanolamine played a key role in determining sheep meat quality, which was regulated by GPAT2, PLPP2, AGPAT1, PNPLA2, and GPAT4 and correlated with meat color, texture, and flavor. Overall, these results will provide effective information and more evidence to support further exploration of valuable biomarkers of meat quality. [ABSTRACT FROM AUTHOR]

At the alpine meadow in Guinan County, Qinghai Province, the responses of leaf structural and functional traits of Poa crymophila, Carex qinghaiensis and Potentilla anserine were studied through the experiment of simulating different grazing modes. The results show that compared with the fenced grassland (FG), heavy grazing leads to significant decreasing in the leaf dry matter content (LDMC) of C. qinghaiensis, and the grazing mode has no effect on the LDMC of P. crymophila and P. anserine. Grazing leads to significant increase in the specific leaf area (SLA) of C. qinghaiensis and P. anserine. Compared with FG, grazing resultes in a significant decreasing in leaf carbon content (LCC), a significant increasing in nitrogen and phosphorus content (LPC), and a significant downward trend in C / N, C / P and N / P. The plasticity of leaf traits in response to grazing is different. The plasticity of LPC is strong and a sensitive trait, while the plasticity index of LCC is the lowest and an inert trait. The variability of LDMC and SLA is the largest. In conclusion, the response patterns of leaf traits of the three herbs to grazing are different and related to grazing modes. The asymmetric change of leaf phenotypic traits is the result of trade-off between traits,which might be an adaptive strategy to grazing activities. [ABSTRACT FROM AUTHOR]

Simple Summary: Yaks are one of the sources of greenhouse gas emissions from livestock farming on the Qinghai–Tibet Plateau region, and regulating greenhouse gas emissions from yaks has important ecological significance. In this study, we evaluated potential links between basal diet, rumen microbiota composition, and CH4 and CO2 emissions of yaks under different feeding regimes. We found the CO2 and CH4 emissions of yaks were lower in traditional grazing than in warm-grazing and cold-indoor feeding regimes. The rumen microbiota of the yaks changed because of differences in basal diet. The CO2 and CH4 emissions of yaks were related to complementarity among members of the rumen functional genera. We believe that shifts in feeding regimes are effective measures reducing greenhouse gas emissions from yaks and rumen microbiome characterization could be useful screening tools for selecting yaks with low gas emissions. Shifts in feeding regimes are important factors affecting greenhouse gas (GHG) emissions from livestock farming. However, the quantitative values and associated drivers of GHG emissions from yaks (Bos grunniens) following shifts in feeding regimes have yet to be fully described. In this study, we aimed to investigate CH4 and CO2 emissions differences of yaks under different feeding regimes and their potential microbial mechanisms. Using static breathing chamber and Picarro G2508 gas concentration analyzer, we measured the CO2 and CH4 emissions from yaks under traditional grazing (TG) and warm-grazing and cold-indoor feeding (WGCF) regimes. Microbial inventories from the ruminal fluid of the yaks were determined via Illumina 16S rRNA and ITS sequencing. Results showed that implementing the TG regime in yaks decreased their CO2 and CH4 emissions compared to the WGCF regime. The alpha diversity of ruminal archaeal community was higher in the TG regime than in the WGCF regime. The beta diversity showed that significant differences in the rumen microbial composition of the TG regime and the WGCF regime. Changes in the rumen microbiota of the yaks were driven by differences in dietary nutritional parameters. The relative abundances of the phyla Neocallimastigomycota and Euryarchaeota and the functional genera Prevotella, Ruminococcus, Orpinomyces, and Methanobrevibacter were significantly higher in the WGCF regime than in the TG regime. CO2 and CH4 emissions from yaks differed mainly because of the enrichment relationship of functional H2- and CO2-producing microorganisms, hydrogen-consuming microbiota, and hydrogenotrophic methanogenic microbiota. Our results provided a view that it is ecologically important to develop GHG emissions reduction strategies for yaks on the Qinghai–Tibet Plateau based on traditional grazing regime. [ABSTRACT FROM AUTHOR]

Simple Summary: Chaka sheep are adapted to a harsh, highly saline environment and are also known for having typical sensory characteristics attributed to free-range conditions and grazing on wild plants. Black Tibetan sheep are located in Guinan county, Tibetan Autonomous Prefecture of Hainan, Qinghai Province, and are well-adapted to the harsh plateau environment in China. In this study, we compared the fatty acids and metabolites in the longissimus dorsi muscle between Black Tibetan and Chaka sheep grazing in a highly saline environment. We found that upregulated organic acid and fatty acid biosynthesis increased the meat quality of Chaka sheep. The objective of this study was to investigate and compare fatty acids and metabolites in the longissimus dorsi muscle between Black Tibetan and Chaka sheep grazing in a highly saline environment. A total of eight castrated sheep (14 months old) with similar body weights (25 ± 2.2 kg) were selected. The experimental treatments included Black Tibetan (BT) and Chaka sheep (CK) groups, and each group had four replications. The experiment lasted for 20 months. All sheep grazed in a highly saline environment for the whole experimental period and had free access to water. The results showed that the diameter (42.23 vs. 51.46 μm), perimeter (131.78 vs. 166.14 μm), and area of muscle fibers (1328.74 vs. 1998.64 μm2) were smaller in Chaka sheep than in Black Tibetan sheep. The ash content in the longissimus dorsi was lower in Chaka sheep than in Black Tibetan sheep (p = 0.010), and the contents of dry matter (DM), ether extract (EE), and crude protein (CP) in the longissimus dorsi showed no differences (p > 0.05). For fatty acids, the proportions of C10:0, C15:0, and tC18:1 in the longissimus dorsi were higher in Chaka sheep than in Black Tibetan sheep (p < 0.05). However, all other individual fatty acids were similar among treatments, including saturated fatty acids (SFAs), unsaturated fatty acids (UFAs), monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), and the ratios of n-6 PUFAs to n-3 PUFAs and PUFAs to SFAs (p > 0.05). A total of 65 biomarkers were identified between the two breeds of sheep. Among these metabolites, 40 metabolic biomarkers were upregulated in the CK group compared to the BT group, and 25 metabolites were downregulated. The main metabolites include 30 organic acids, 9 amino acids, 5 peptides, 4 amides, 3 adenosines, 2 amines, and other compounds. Based on KEGG analysis, eight pathways, namely, fatty acid biosynthesis, purine metabolism, the biosynthesis of unsaturated fatty acids, renin secretion, the regulation of lipolysis in adipocytes, neuroactive ligand–receptor interaction, the cGMP-PKG signaling pathway, and the cAMP signaling pathway, were identified as significantly different pathways. According to the results on fatty acids and metabolites, upregulated organic acid and fatty acid biosynthesis increased the meat quality of Chaka sheep. [ABSTRACT FROM AUTHOR]

Grazing, as an important land use method in grassland, has a significant impact on the morphological and physiological traits of plants. However, little is known about how the molecular mechanism of plant responds to different grazing intensities. Here, we investigated the response of Taraxacum mongolicum to light grazing and heavy grazing intensities in comparison with a non-grazing control. Using de novo transcriptome assembly, T. mongolicum leaves were compared for the expression of the different genes under different grazing intensities in natural grassland. In total, 194,253 transcripts were de novo assembled and comprised in nine leaf tissues. Among them, 11,134 and 9058 genes were differentially expressed in light grazing and heavy grazing grassland separately, with 5867 genes that were identified as co-expression genes in two grazing treatments. The Nr, SwissProt, String, GO, KEGG, and COG analyses by BLASTx searches were performed to determine and further understand the biological functions of those differentially expressed genes (DEGs). Analysis of the expression patterns of 10 DEGs by quantitative real-time RT-PCR (qRT-PCR) confirmed the accuracy of the RNA-Seq results. Based on a comparative transcriptome analysis, the most significant transcriptomic changes that were observed under grazing intensity were related to plant hormone and signal transduction pathways, carbohydrate and secondary metabolism, and photosynthesis. In addition, heavy grazing resulted in a stronger transcriptomic response compared with light grazing through increasing the of the secondary metabolism- and photosynthesis-related genes. These changes in key pathways and related genes suggest that they may synergistically respond to grazing to increase the resilience and stress tolerance of T. mongolicum. Our findings provide important clues for improving grassland use and protection and understanding the molecular mechanisms of plant response to grazing. [ABSTRACT FROM AUTHOR]

As one of the most economically significant Oleaceae family members, Jasminum sambac is renowned for its distinct sweet, heady fragrance. Using Illumina reads, Nanopore long reads, and HiC‐sequencing, we efficiently assembled and annotated the J. sambac genome. The high‐quality genome assembly consisted of a total of 507 Mb sequence (contig N50 = 17.6 Mb) with 13 pseudomolecules. A total of 21,143 protein‐coding genes and 303 Mb repeat sequences were predicted. An ancient whole‐genome triplication event at the base of Oleaceae (~66 million years ago [Ma], Late Cretaceous) was identified and this may have contributed to the diversification of the Oleaceae ancestor and its divergence from the Lamiales. Stress‐related (e.g., WRKY) and flowering‐related (e.g., MADS‐box) genes were located in the triplicated regions, suggesting that the polyploidy event might have contributed adaptive potential. Genes related to terpenoid biosynthesis, for example, FTA and TPS, were observed to be duplicated to a great extent in the J. sambac genome, perhaps explaining the strong fragrance of the flowers. Copy number changes in distinct phylogenetic clades of the MADS‐box family were observed in J. sambac genome, for example, AGL6‐ and Mα‐ were lost and SOC‐ expanded, features that might underlie the long flowering period of J. sambac. The structural genes implicated in anthocyanin biosynthesis were depleted and this may explain the absence of vivid colours in jasmine. Collectively, assembling the J. sambac genome provides new insights into the genome evolution of the Oleaceae family and provides mechanistic insights into floral properties. [ABSTRACT FROM AUTHOR]

To improve performance and optimize rumen function in yaks (Bos grunniens), further knowledge on the appropriate dietary protein levels for ruminal microbiota and the metabolite profiles of yaks in feedlot feeding is necessary. Current understanding of dietary protein requirements, ruminal microbiota, and metabolites is limited. In this study, yaks were fed a low-protein diet (L; 9.64%), middle low-protein diet (ML; 11.25%), middle high-protein diet (MH; 12.48%), or a high-protein diet (H; 13.87%), and the effects of those diets on changes and interactions in ruminal microbiota and metabolites were investigated. Twenty-four female yaks were selected, and the effects on ruminal microbiota and metabolites were investigated using 16s rRNA gene sequencing and gas chromatography time-of-flight/mass spectrometry (GC-TOF/MS). Diets containing different protein levels changed the composition of the rumen bacterial community, the H group significantly reduced the diversity of ruminal microbiota (p < 0.05), and the number of shared amplicon sequence variants (ASVs) between the H group and the other three groups was lower, suggesting that the ruminal microbiota community fluctuated more with a high-protein diet. In rumen, Bacteroidetes , Firmicutes , and Proteobacteria were the most abundant bacteria at the phylum level, and Bacteroidetes was significantly less abundant in the MH group than in the L and ML groups (p < 0.05). Prevotella_1 , Rikenellaceae_RC9_gut_group , and Christensenellaceae_R-7_group had the highest abundance at the genus level. Prevotellaceae was enriched in the low-protein groups, whereas Bacteroidales_BS11_gut_group was enriched in the high-protein groups. Rumen metabolite concentrations and metabolic patterns were altered by dietary protein levels: organic acid metabolites, antioxidant-related metabolites, and some plant-derived metabolites showed variation between the groups. Enrichment analysis revealed that significant changes were concentrated in six pathways, including the citrate cycle (TCA cycle), glyoxylate and dicarboxylate metabolism, and butanoate metabolism. Network analysis showed promotion or restraint relationships between different rumen microbiota and metabolites. Overall, the rumen function was higher in the MH group. This study provides a reference for appropriate dietary protein levels and improves understanding of rumen microbes and metabolites. [ABSTRACT FROM AUTHOR]

Drought and heat stresses are two major environmental stress factors that severely threaten crop growth and productivity. Plant delay of germination 1-like (DOG1L) family genes play important roles in various developmental processes and stress responses. In our previous study, a tobacco DOG1L gene (NtDOG1L-T) was found to regulate seedling growth and drought response. Unfortunately, the role of DOG1L genes in heat stress response is yet to be studied. Here, we present data supporting the role of DOG1L genes in heat stress and possible underlying molecular mechanisms. Transcript levels of NtDOG1L-T were rapidly induced by heat or abscisic acid (ABA) treatment. Furthermore, NtDOG1L-T promoter activity was markedly activated by ABA or heat stress, as revealed by histochemical staining in transgenic tobacco seedlings. Overexpression of NtDOG1L-T in transgenic lines improved heat stress tolerance. The NtDOG1L-T -transgenic plants exhibited lower levels of reactive oxygen species (ROS) and lipid peroxidation but higher antioxidant enzyme activities in response to heat stress. Furthermore, transcript abundance of some defense-, heat-, and ABA-responsive marker genes was significantly upregulated, as shown by reverse transcription quantitative PCR (qPCR) in these transgenic plants. In conclusion, NtDOG1L-T positively regulates heat stress tolerance possibly by modulation of antioxidant capability and defense-, heat-, and ABA-related gene expression in tobacco. This study may provide valuable resource for the potential exploitation of DOG1Ls in genetic improvement of heat stress tolerance in crops. [ABSTRACT FROM AUTHOR]

The rumen microbiota is strongly associated with host health, nutrient absorption, and adaptability. However, the composition, functioning and adaptability of rumen microbiota in Tibetan sheep (TS) across different phenological periods are unclear. In this study we used sequencing of the V4-V5 region of 16S rRNA, qPCR technology and metagenomics to investigate the adaption of rumen microbiota to forage in different stages of phenology. In a grassy period, due to the high nutritional quality of the forage, TS can produce high concentrations of NH3-N and short fatty acids by increasing the content of key bacteria in the rumen, such as Bacteroidetes, Prevotella , Succiniclasticum , Treponema , Butyrivibrio fibrisolvens , Fibrobacter succinogenes , Prevotella ruminicola , Ruminococcus albus , and Ruminococcus flavefaciens to aid in growth. In the withering period, there was a positive correlation between microorganisms which indicated the closely cooperation between microorganisms, and metagenomic analysis showed that the high genes (GHs and CBMs) and subtribe (GH8, GH12, GH45, GH6, GH9, GH5, GH10, GH3, GH52, GH11, GH57, CBM1, CBM4, CBM6, CBM16, CBM37, CBM13, CBM35, CBM42, CBM32, and CBM62) that encode cellulolytic enzymes were significantly increased when the host faced low quantity and quality of forage. Genes involved in metabolic pathways, fatty acid biosynthesis and biosynthesis of antibiotics were significantly enriched, which indicated that rumen microbiota could improve plant biomass deconstruction and energy maintenance in the face of nutritional deficiencies. In the regreen period, both the composition and function of rumen microbiota had obvious disadvantages, therefore, to improve the competitiveness of microorganisms, we suggest TS should be supplemented with high-protein feed. This study is of great significance for exploring the high altitude adaptability of TS. [ABSTRACT FROM AUTHOR]

The Tibetan antelope (Pantholops hodgsonii), blue sheep (Pseudois nayaur), and Tibetan sheep (Ovis aries) are the dominant small ruminants in the Three‐River‐Source National Park (TRSNP). However, knowledge about the association between gut microbiota and host adaptability remains poorly understood. Herein, multi‐omics sequencing approaches were employed to investigate the gut microbiota‐mediated forage adaption in these ruminants. The results revealed that although wild ruminants (WR) of P. hodgsoni and P. nayaur were faced with severe foraging environments with significantly low vegetation coverage and nutrition, the apparent forage digestibility of dry matter, crude protein, and acid detergent fiber was significantly higher than that of O. aries. The 16s rRNA sequencing showed that the gut microbiota in WR underwent convergent evolution, and alpha diversity in these two groups was significantly higher than that in O. aries. Moreover, indicator species, including Bacteroidetes and Firmicutes, exhibited positive relationships with apparent forage digestibility, and their relative abundances were enriched in the gut of WR. Enterotype analysis further revealed that enterotype 1 belonged to WR, and the abundance of fatty acid synthesis metabolic pathway‐related enzyme genes was significantly higher than enterotype 2, represented by O. aries. Besides, the metagenomic analysis identified 14 pathogenic bacterial species, among which 10 potentially pathogenic bacteria were significantly enriched in the gut microbiota of O. aries. Furthermore, the cellulolytic strains and genes encoding cellulase and hemicellulase were significantly enriched in WR. In conclusion, our results provide new evidence of gut microbiota to facilitate wildlife adaption in severe foraging environments of the TRSNP, China. [ABSTRACT FROM AUTHOR]

Aims The Qinghai-Tibetan Plateau has a mean altitude exceeding 4000 m and covers about 2.5 million km2. More than 60% of this area is alpine grassland. Exclosures have been widely used in this region to study the sustainable use of grassland resources. We used patterns of functional trait diversity to infer the effects of exclosures on community assembly in alpine meadows. Methods We studied functional diversity using five traits under grazing and three enclosed (exclosure) plots (3, 8, and 18 years old) in an alpine meadow on the Qinghai-Tibetan Plateau. We quantified the strength of the community assembly processes by comparing the observed functional trait diversity with a null model that assumes random community assembly. Important findings We found evidence for deterministic assembly processes for plant communities in exclosures. The changes in CWM of the five traits from grazing land to 18-year exclosure indicated that environmental filtering occurred due to the exclosures. Multivariate functional diversity (MFDis and MPDses), and functional diversity of individual traits, including that of leaf area, leaf weight and aboveground biomass (FDis of leaf area, leaf weight, and aboveground biomass), increased gradually from grazing land to the 18-year exclosure, and the values of the 18-year exclosure were significantly greater than null expectation. This can be interpreted to indicate that exclosures resulted in greater competitive interaction between species. These results suggest that the effect of exclosures on community assembly is more deterministic than stochastic in this meadow. [ABSTRACT FROM AUTHOR]

Root-knot nematodes (RKNs, Meloidogyne spp.) are destructive plant parasites with a wide host range. They severely reduce crop quality and yield worldwide. Tobacco is a versatile model plant organism for studying RKNs-host interactions and a key plant material for molecular research. Long noncoding RNAs (lncRNAs) play critical roles in post transcriptional and transcriptional regulation in a wide range of biological pathways, especially plant development and stress response. In the present study, we obtained 5,206 high-confidence lncRNAs based on RNA sequencing data. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses revealed that the target genes of these lncRNAs are mainly involved in plant biotic and abiotic stresses, plant hormone signal transduction, induced systemic resistance, plant-type hypersensitive response, plant-type cell wall organization or biogenesis. The 565 differentially expressed lncRNAs found to be involved in nematode stress response were validated by quantitative PCR using 15 randomly-selected lncRNA genes. Our study provides insights into the molecular mechanisms of RKNs-plant interactions that might help preventing nematode damages to crops. [ABSTRACT FROM AUTHOR]

Yak and Tibetan sheep are the major indigenous ruminants on the Qinghai-Tibetan Plateau in China. The aim of this work was to study the differences in ruminal fermentation parameters and rumen prokaryotic community composition between hosts and feeding paradigms. The 16S rRNA genes targeting bacteria and archaea were sequenced using the MiSeq platform. The results showed that the prokaryotic community structure between yak and Tibetan sheep was significantly different ( P < 0.01). A significant difference in structure was also found between groups of yaks barn fed with a total mixed ration (TMR) and those naturally grazing (NG) ( P = 0.034), as well as for Tibetan sheep of the two groups ( P = 0.026). The core prokaryotic populations that existed in the rumen mostly dominated the structure. There was an obvious correlation of the prokaryotic community composition at the phylum and genus levels with the host or the feeding pattern. In addition, Tibetan sheep showed significantly higher yields of volatile fatty acids (VFAs) than yak, as did the NG group compared with the TMR group. In conclusion, both the host and feeding pattern may influence rumen microbial ecology system, with host effects being more important than those of the feeding pattern. [ABSTRACT FROM AUTHOR]

Pastoralists on the Tibetan alpine rangeland suffered great economic loss in cold season, due to serious live-weight loss of domestic livestock under traditional grazing management. This study aimed to evaluate the effect of dietary types (crude protein levels) on feed intakes, growth performance and economic returns of local Tibetan sheep and yaks during cold season. Twenty-four yearling Tibetan sheep (25.29±3.95 kg LW) and twenty two-year-old yaks (100.62±4.55 kg LW) with familiar body conditions were randomly assigned to four groups, fed oats hay (OH), oats silage (OS), total mixed ration (TMR) and traditionally grazed on the local cool-season pasture (TG), respectively, over a 135-day experiment. Daily dry matter intake was determined; all animals were weighed at the beginning and every 15 days of the 135-day experiment. Then, the total live-weight gain, average daily live-weight gain, gain rate, feed efficiency and net economic benefit were calculated. Results indicated that feed and nutrient intakes (DMI, DMI/kg LW, DMI/kg LW0.75 and CPI) of TMR, OH and OS were higher than TG (P < 0.05). Grazing animals suffered serious live-weight loss, while TMR, OS and OH significantly (P < 0.05) improved total live-weight gain and gain rate in both Tibetan sheep and yaks during the entire experiment. TMR worked better in animal performance and feed efficiency, obtained the highest breeding profit in both Tibetan sheep and yaks among four treatments (P < 0.05). When expressed on net economic benefit, TMR shared the highest net economic benefit in Tibetan sheep, OH shared the highest net economic benefit in yaks, but, no significant difference of net economic benefit in yaks fed TMR and OH diets was determined (P > 0.05). Results indicated that TMR was a reasonable diet in promoting feed intakes, animal performance, feed efficiency and economic returns in domestic livestock, which should be considered by local herdsmen to increase their breeding profit during cold season. [ABSTRACT FROM AUTHOR]

The study by the eddy covariance technique in the alpine shrub meadow of the Qinghai-Tibet Plateau in 2003 and 2004 showed that the net ecosystem carbon dioxide exchange (NEE) exhibited noticeable diurnal and annual variations, with more distinct daily changes during the warmer seasons. The CO2 emission of the shrub ecosystem culminated in April and September while the CO2 absorption capacity reached a maximum in July and August. The absorbed carbon dioxide during the two consecutive years was 231.4 and 274.8 g CO2·m−2 respectively, yielding an average of 253.1 gCO2·m−2 per year: that accounts for a large proportion of absorbed CO2 in the region. Obviously, the diurnal carbon flux was negatively related to temperature, radiation and other atmospheric factors. Still, minute discrepancies in kurtosis and duration of carbon emission/absorption were detected between 2003 and 2004. It was found that the CO2 flux in the daytime was similarly affected by photosynthetic photon flux density in both years. Temperature appears to be the most important determinant of CO2 flux: specifically, the high temperature during the plant growing season inhibits the carbon absorption capacity. One potential explanation is that soil respiration is enhanced under such condition. Analysis of biomass revealed that the annual net carbon fixed capacity of aboveground and belowground biomass was 544.0 in 2003 and 559.4 g C·m−2 in 2004, which coincided with the NEE absorption capacity (63.1 g C·m−2 in 2003 and 74.9 g C·m−2 in 2004) in the corresponding plant growing season. [ABSTRACT FROM AUTHOR]

Simple Summary: The Qinghai–Tibetan plateau is considered as the third Pole of the world and is characterized by low oxygen, high altitude, extreme cold weather and strong ultraviolet radiation. Yak, as the main domestic animals raised on the plateau, play various roles in local herdsmen's lives by supplying necessities such as meat, milk and fuel. Yak are adapted to the harsh environment on the plateau; microbiota in gut equip the hosts with special abilities including adaptability, as illustrated by numerous research projects. Accordingly, the microbes in the gastrointestinal tract of yak must be characteristically profiled as a strategy to adapt to the environment. However, little is known about the microbial community in whole tract of yak; almost all of reported researches focused on rumen. Therefore, in the current study the bacterial community in the gastrointestinal tract of yak was explored using 16S rDNA amplicon sequencing technology, and the community profiling characteristic in each section was clearly elucidated. In the current research, samples of yak gastrointestinal tracts (GITs) were used to profile the bacterial compositional characteristics using high through-put sequencing technology of 16S RNA amplicon. A total of 6959 OTUs was obtained from 20,799,614 effective tags, among which 751 OTUs were shared by ten sections. A total of 16 known phyla were obtained in all samples—the most abundant phyla were Firmicutes (34.58%), Bacteroidetes (33.96%) and Verrucomicrobia (11.70%). At the genus level, a total of 66 genera were obtained—Rikenellaceae_RC9_gut_group (7.24%), Akkermansia (6.32%) and Ruminococcaceae_UCG-005 (6.14%) were the most abundant. Species of Observed (Sob), Shannon and Chao values of the Stomach were the greatest, followed by the large intestine, while small intestine had the lowest diversity (p < 0.05). Bacteroidete were more abundant in sections from rumen to duodenum; while Firmicutes were the most abundant in sections from jejunum. ABC transporters (7.82%), Aminoacyl-tRNA biosynthesis (4.85%) and Purine metabolism (3.77%) were the most abundant level-3 pathways in all samples. The results of associated correlation analysis indicated that rectum samples might be used as an estimator of rumen bacterial communities and fermentation. The results of this research enrich the current knowledge about the unique animals of the QTP and extend our insight into GITs microecology of various animals. [ABSTRACT FROM AUTHOR]

Simple Summary: The Tibetan sheep (Ovis aries) is an ovine breed well adapted to the harsh plateau environment. For a long period of time, Tibetan sheep farming has been an important pillar industry for native herders on the Qinghai-Tibetan Plateau. With the increasing demand for sheep meat and products, nutrition research has gained increasing importance. In this study, the effects of three different dietary protein levels (10.1%, 12.1%, and 14.1%) on growth performance, carcass traits, serum metabolites, and meat composition were investigated in Tibetan sheep during the cold season. The results showed that the diets containing 12.1% and 14.1% protein were better than a diet containing 10.1% protein for enhancing the growth performance, carcass performance, and meat products of the Tibetan sheep. Dietary protein is a critical nutrient that directly influences the health and production of livestock. Recent studies showed that protein supplements could enhance the growth performance of Tibetan sheep. However, there is a lack of information regarding the influence of dietary protein levels on carcass traits and meat composition. This study investigated the effects of dietary protein levels on growth performance, carcass traits, serum metabolites, and meat composition in Tibetan sheep during the cold season on the Qinghai-Tibetan Plateau. A total of eighteen 1-year-old, healthy, castrated Tibetan sheep with similar initial body weights (31.7 ± 0.72 kg) were randomly divided into three treatment groups with different dietary protein level (low protein (LP, 10.1%); medium protein (MP, 12.1%); high protein (HP, 14.1%)) diets. The results indicated that the Tibetan sheep fed with the MP and HP diets had greater final body weights (BWs), average daily gains (ADGs), and average daily feed intakes (ADFIs) (p < 0.05). The MP and HP diets also improved the hot carcass weight, net meat (including the fat) weight, and bone weight of the sheep significantly (p < 0.05). Besides, the dietary protein levels could significantly affect the serum concentrations of growth hormone (p < 0.05). The diameter of muscle fibers in the MP group was significantly greater than that in the LP group (p < 0.05), while the density of muscle fibers showed the opposite trend. The dietary protein levels only significantly (p < 0.05) influenced the ether extract content and profile content of the longissimus dorsi muscle but had no effect on other parameters of meat composition. In summary, our results indicate that dietary protein levels affect growth performance, carcass traits, and meat composition and that diets containing 12.1% and 14.1% protein are recommended to obtain better production performance and meat products in Tibetan sheep, rather than a diet containing 10.1% protein, during the cold season on the Qinghai-Tibetan Plateau. [ABSTRACT FROM AUTHOR]

Herein, methane (CH 4 ), carbon dioxide (CO 2 ) and nitrous oxide (N 2 O) emission from different aged barn feeding Tibetan sheep were characterized using a respiration chamber in combination with gas chromatograph method in cold season of 2013. This work was based on measuring the increase of gas concentration inside respiration chamber by the means of gas chromatograph. Results indicated that diurnal CH 4 emission patterns for barn feeding Tibetan sheep were driven by feeding schedule, diurnal CO 2 emission patterns were relatively stable with two slight emission peaks, diurnal N 2 O emission patterns were driven by the variation of temperature inside chamber. Diurnal CH 4 emission rates were 17.65, 19.49 and 21.06 g sheep −1 d −1 for yearling, two-year and three-year barn feeding Tibetan sheep, account for 6.15%, 5.76% and 5.45% of their daily gross energy intakes, respectively. Diurnal CO 2 emission rates were 526.88, 588.43 and 640.66 g sheep −1 d −1 for yearling, two-year and three-year barn feeding Tibetan sheep, respectively. Diurnal N 2 O emission rates were 1.64, 1.25 and 1.05 mg sheep −1 d −1 for yearling, two-year and three-year barn feeding Tibetan sheep, respectively. Three-year barn feeding Tibetan sheep released more CO 2 -eq on per unit BW and BW 0.75 gain basis. [ABSTRACT FROM AUTHOR]

Anthropogenic changes in land use/cover have altered the vegetation, soil, and carbon (C) cycling on the Qinghai–Tibetan Plateau (QTP) over the last ~ 50 years. As a result, the Grain for Green Program (GfGP) has been widely implemented over the last 10 years to mitigate the impacts of cultivation. To quantify the effects of the GfGP on C partitioning and turnover rates at the ecosystem scale, an in situ 13 C pulse labeling experiment was conducted on natural and GfGP grasslands in an agro-pastoral ecotone in the Lake Qinghai region on the QTP. We found that there were significant differences in the C stocks of all the considered pools in both the natural and GfGP grasslands, with higher CO 2 uptake rates in the GfGP grassland than that in the natural grassland. Partitioning of photoassimilate (% of recovered 13 C) in C pools of both grasslands was similar 25 days after labeling, except in the roots of the 0–15 and 5–15 cm soil layer. Soil organic C (SOC) sequestration rate in the GfGP grassland was 11.59 ± 1.89 g C m − 2 yr − 1 significantly greater than that in the natural grassland. The results confirmed that the GfGP is an efficient approach for grassland restoration and C sequestration. However, it will take more than a century (119.19 ± 20.26 yr) to restore the SOC stock from the current cropland baseline level to the approximate level of natural grassland. We suggest that additional measures are needed in the selection of suitable plant species for vegetation restoration, and in reasonable grazing management. [ABSTRACT FROM AUTHOR]

There is an increasing awareness of the adverse environmental effects of the intensive practices used in modern crop farming, such as those that cause greenhouse gas emissions and nutrient leaching. Harnessing beneficial microbes by changing planting practices presents a promising strategy for optimizing plant growth and agricultural sustainability. However, the characteristics of soil microorganisms under different planting patterns remain uncertain. We conducted a study of soil bacterial structure and function under monoculture vs. polyculture planting regimes using 16S rRNA gene sequencing on the Qinghai–Tibet Plateau. We observed substantial variations in bacterial richness, diversity, and relative abundances of taxa between gramineous and leguminous monocultures, as well as between gramineae–legume polycultures. The number of operational taxonomic units and alpha and beta diversity were markedly higher in the leguminous monocultures than in the gramineous monocultures; conversely, network analysis revealed that the interactions among the bacterial genera in the gramineous monocultures were more complex than those in the other two planting regimes. Moreover, nitrogen fixation, soil detoxification, and productivity were increased under the gramineous monocultures; more importantly, low soil-borne diseases (e.g., animals parasitic or symbiont) also facilitated strongly suppressive effects toward soil-borne pathogens. Nevertheless, the gramineae–legume polycultures were prone to nitrate seepage contamination, and leguminous monocultures exhibited strong denitrification effects. These results revealed that the gramineous monoculture is a more promising cropping pattern on the Qinghai–Tibetan Plateau. Understanding the bacterial distribution patterns and interactions of crop-sensitive microbes presents a basis for developing microbial management strategies for smart farming. [ABSTRACT FROM AUTHOR]

• Rumen bacteria community of Tibetan sheep was predominated by phyla Bacteroidetes, Firmicute and Verrucomicrobia at phylum level, as to genus , Rikenellaceae_RC9_gut_group and Prevotella_1 predominated. • Sex and age were two important factors which shaping the rumen bacterial composition of Tibetan sheep as previous reported on mice and human. • Most of predicted function genes significantly enriched in adult female sheep compared with adult male sheep and yearling female sheep, respectively. In this study, 18 Tibetan sheep were assigned into four groups by age and sex, namely young ewes (E1, n = 5), young rams (R1, n = 3), adult ewes (EA, n = 5) and adult rams (RA, n =5) to profile the bacterial composition of Tibetan sheep and to explore the impacts of sex and age on rumen microbiota using high-throughput sequencing method of amplicon of 16S rRNA V3–V4 region. The results indicated that all effective tags for 18 samples were clustered into 5429 OTUs (Operation taxonomic Units, OTUs) with an absolute abundance > 1 at a similarity level > 97%. The rumen bacterial composition of female adult sheep was more diverse than male adult sheep and yearling female sheep. SILVA database was used to annotate taxonomic information for each representative sequence using the RDP classifier, the results showed that Bacteroidetes, Firmicutes, Verrucomicrobia and Proteobacteria were the most dominant phyla, representing 56.68%, 28.81%, 6.71% and 1.73% of reads from all samples on average, respectively. At the genus level, Rikenellaceae_RC9_gut_group , and Prevotella_1 were most abundant with relative abundance of 12.98% and 11.19%, respectively. Relative abundance of Bacteroidetes in EA was greater than RA (p = 0.014), relative abundance of Firmicutes in RA was greater than EA (p < 0.001), and the relative abundance of Spirochaetae in E1 was greater than R1 (p = 0.038). Shifting genera between the sexes belonged to Order Bacteroidales and Clostridiales , both changed substantially across sex in adult sheep (p < 0.01). The abundance of Bacteroidetes in female sheep and Firmicutes and Planctomycetes in male sheep significantly increased with age (p < 0.05), while the abundance of Spirochaetae in female sheep and Cyanobacteria in male sheep decreased with age (p < 0.05). Shifting genera between age groups belonged to order Bacteroidales and Clostridial. The abundance of order Bacteroidales in female sheep increased with age (p = 0.046), and the abundance of order Clostridiales in male sheep increased with age (p = 0.006), while it decreased with age in female sheep (p = 0.030). In summary, this study profiled the bacterial composition characteristics of Tibetan sheep and concluded that physiological factors, e.g. sex and age, shaped the bacterial composition, which expands our knowledge of the rumen of ruminant animals residing on the Qinghai-Tibetan Plateau. [ABSTRACT FROM AUTHOR]