Livestock turnover and dynamic livestock carrying capacity are crucial factors for alpine grassland management: The Qinghai-Tibetan plateau as a case study.

Alpine grasslands are distributed widely on high-elevated ranges and plateaus from the wet tropics to polar regions, accounting for approximately 3% of the world's land area. The Qinghai-Tibetan Plateau (QTP) is the highest and largest plateau in the world, and approximately 60% of the plateau consists of alpine grassland, which is used mainly for grazing animals. Livestock structure was determined in Guinan (GN), Yushu (YS) and Maqu counties (MQ) on the QTP by interviewing 235 local pastoralists. Based on data collected from GN, the livestock carrying capacity was calculated using herbage dry matter biomass intake (LCCm) by the livestock, and the metabolizable energy yield (LCCe) and digestible crude protein (LCCp) available in pasture. The pasture area per household differed among the regions of the QTP, which was the main reason for the difference in livestock stocking rate. The householders raised the appropriate proportion of breeding females and young yaks and sheep in GN and MQ, but not in YS, to maintain a constant turnover. Most pasture in YS was used at the community level, especially in summer. The calculated carrying capacities based on metabolizable energy yield (LCCe) of the pasture and dry matter biomass (LCCm) were similar in most months except for August, when the value of LCCe was higher than LCCm. Based on the digestible protein of the pasture, the calculated livestock carrying capacity overestimated the actual carrying capacity during the herbage growing season from May to September. Appropriate practices should be taken in different regions of QTP, such as providing supplementary feed, especially protein, during the forage non-growing season. Livestock carrying capacity should be adjusted dynamically, and calculated by a number of parameters. The stocking rate should be controlled to optimize livestock production and curb or minimize grassland degradation to generate a sustainable system. This study examined the grasslands and LCC on the QTP, but the results could be applied to grasslands worldwide.

The water extract of Rheum palmatum has antioxidative properties and inhibits ROS production in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Rheum palmatum (RP) is a widely used traditional herb, which possesses antioxidant properties, inhibits ROS production and reduces fever. AIM OF THE STUDY: The aim of this study was to examine the antioxidative properties of the water extract of RP on oxidative-stressed mice. MATERIALS & METHODS: Forty mice were administered with DL-homocysteine (DL-Hcy) to induce oxidative stress and were divided into four groups: 1) CK: NaCl and water; 2) DL-Hcy: DL-Hcy and water; 3) DL-Hcy+50RP: DL-Hcy with 50 mg kg-1 body weight (BW) d-1 RP; and 4) DL-Hcy+150RP: DL-Hcy with 150 mg kg-1 BW d-1 RP. Rhein (0.3 mg g-1 dry matter) was the main active ingredient in RP. RESULTS: When compared with Dl-Hcy mice, the mice with supplementary RP mitigated oxidative stress by reducing the liver concentrations of superoxide dismutase (SOD) by 27% and glutathione peroxidase (GSH-Px) by 32%, and the reactive oxygen species (ROS) in the kidney and spleen. These responses were more pronounced in DL-Hcy+150RP than DL-Hcy+50RP mice. RP also exhibited therapeutic effects on liver steatosis, chronic kidney nephritis and intestinal villus width shortening caused by oxidative stress, and concomitantly decreased the serum glucose concentration (RP vs. DL-HCY, 2.3 vs. 4.1 mmol L-1). CONCLUSION: It was concluded that RP possesses antioxidant and therapeutic properties that can mitigate lesions on organs and prevent diabetes in oxidative-stressed mice. This study highlights the potential of RP as a medicinal supplement for animals in the future.

Linkages between rumen microbiome, host, and environment in yaks, and their implications for understanding animal production and management.

Livestock on the Qinghai-Tibetan Plateau is of great importance for the livelihood of the local inhabitants and the ecosystem of the plateau. The natural, harsh environment has shaped the adaptations of local livestock while providing them with requisite eco-services. Over time, unique genes and metabolic mechanisms (nitrogen and energy) have evolved which enabled the yaks to adapt morphologically and physiologically to the Qinghai-Tibetan Plateau. The rumen microbiota has also co-evolved with the host and contributed to the host's adaptation to the environment. Understanding the complex linkages between the rumen microbiota, the host, and the environment is essential to optimizing the rumen function to meet the growing demands for animal products while minimizing the environmental impact of ruminant production. However, little is known about the mechanisms of host-rumen microbiome-environment linkages and how they ultimately benefit the animal in adapting to the environment. In this review, we pieced together the yak's adaptation to the Qinghai-Tibetan Plateau ecosystem by summarizing the natural selection and nutritional features of yaks and integrating the key aspects of its rumen microbiome with the host metabolic efficiency and homeostasis. We found that this homeostasis results in higher feed digestibility, higher rumen microbial protein production, higher short-chain fatty acid (SCFA) concentrations, and lower methane emissions in yaks when compared with other low-altitude ruminants. The rumen microbiome forms a multi-synergistic relationship among the rumen microbiota services, their communities, genes, and enzymes. The rumen microbial proteins and SCFAs act as precursors that directly impact the milk composition or adipose accumulation, improving the milk or meat quality, resulting in a higher protein and fat content in yak milk and a higher percentage of protein and abundant fatty acids in yak meat when compared to dairy cow or cattle. The hierarchical interactions between the climate, forage, rumen microorganisms, and host genes have reshaped the animal's survival and performance. In this review, an integrating and interactive understanding of the host-rumen microbiome environment was established. The understanding of these concepts is valuable for agriculture and our environment. It also contributes to a better understanding of microbial ecology and evolution in anaerobic ecosystems and the host-environment linkages to improve animal production.