Evaluation of molasses on fermentation profiles of wheat straw ensiled with tall fescue in the southwest Tibet.

Two experiments were carried out to determine the optimal proportion of mixed silage made with wheat straw and tall fescue, and further to evaluate the effects of molasses on fermentation quality. In Experiment 1, wheat straw and tall fescue were mixed at proportions of 10:0 (Control), 8:2 (WT20), 6:4 (WT40) and 4:6 (WT60) on fresh weight (FW) basis. Inclusion of tall fescue significantly (p < 0.05) increased lactic acid, water-soluble carbohydrate contents and ratio of lactic to acetic acid, and significantly (p < 0.05) decreased pH and contents of dry matter, NH3 -N and volatile fatty acids. WT60 had the highest (p < 0.05) lactic acid content, and the lowest (p < 0.05) pH and butyric acid content. In Experiment 2, the mixture of wheat straw and tall fescue (4/6) were treated with 0%, 3%, 4% and 5% molasses on FW basis (defined as control, WTM3, WTM4 and WTM5 respectively). Molasses addition significantly (p < 0.05) increased lactic acid and water-soluble carbohydrate contents, and significantly (p < 0.05) decreased pH and ammonia-nitrogen content as compared with control. Acetic acid content slightly (p > 0.05) decreased during ensiling, while trace amounts of propionic and butyric acids were observed. WTM5 had the lowest pH and the highest (p < 0.05) lactic acid, water-soluble carbohydrate contents and ratio of lactic to acetic acid at end of ensiling. In conclusion, the fermentation quality was maximally improved when the addition rate of molasses was 5% in 40% wheat straw ensiled with 60% tall fescue.

Effect of Lentinus sajor-caju on the chemical composition and antioxidant activity of highland barley straw under solid-state fermentation.

Introduction: The efficient utilization of straw resources as animal feed has gained considerable attention. The objective of this study was to evaluate whether Lentinus sajor-caju treatment alters the chemical composition and antioxidant activity of highland barley straw and enhances its functional value as a ruminant feed. Methods: The chemical composition, antioxidant capacity, and metabolomic profile of highland barley straw were determined after 21 days of solid-state fermentation with L. sajor-caju at 25°C. The differential metabolites between fermented and unfermented highland barley straw were identified by LC-MS and the relationship between the identified metabolites and antioxidant capacity was elucidated. Results: The results showed that, compared with untreated highland barley straw, the crude protein and ether extract contents were higher (51.55 and 76.43%, respectively) in highland barley straw after 21 days of incubation with L. sajor-caju, whereas the hemicellulose, cellulose, and acid detergent lignin contents were lower (2.48, 25.08, and 45%, respectively). The total antioxidant capacity was significantly higher in L. sajor-caju-treated than in untreated highland barley straw. In total, 600 differential metabolites (301 upregulated and 299 downregulated) were identified between L. sajor-caju-fermented and unfermented highland barley straw. Correlation analysis results showed that Fe2+ scavenging and total phenolic content were strongly correlated with total antioxidant capacity. Meanwhile, the differential flavonoid metabolites between fermented and unfermented highland barley straw were primarily associated with antioxidant activity, with kaempferol 3-xylosylglucoside, isoginkgetin, and rhoifolin being the most representative. Conclusion: Thus, this study demonstrates that L. sajor-caju could enhance the functional value of highland barley straw, showing the potential of L. sajor-caju for improving the utilization of agricultural straws in ruminants.

Effects of Bacillus licheniformis and Combination of Probiotics and Enzymes as Supplements on Growth Performance and Serum Parameters in Early-Weaned Grazing Yak Calves.

Early weaning is an effective strategy to improve cow feed utilization and shorten postpartum intervals in cows; however, this may lead to poor performance of the weaned calves. This study was conducted to test the effects of supplementing milk replacer with Bacillus licheniformis and a complex of probiotics and enzyme preparations on body weight (BW), size, and serum biochemical parameters and hormones in early-weaned grazing yak calves. Thirty two-month-old male grazing yaks (38.89 ± 1.45 kg body weight) were fed milk replacer at 3% of their BW and were randomly assigned to three treatments (n = 10, each): T1 (supplementation with 0.15 g/kg Bacillus licheniformis), T2 (supplementation with a 2.4 g/kg combination of probiotics and enzymes), and a control (without supplementation). Compared to the controls, the average daily gain (ADG) from 0 to 60 d was significantly higher in calves administered the T1 and T2 treatments, and that from 30 to 60 d was significantly higher in calves administered the T2 treatment. The ADG from 0 to 60 d was significantly higher in the T2- than in the T1-treated yaks. The concentration of serum growth hormone, insulin growth factor-1, and epidermal growth factor was significantly higher in the T2-treated calves than in the controls. The concentration of serum cortisol was significantly lower in the T1 treatment than in the controls. We concluded that supplementation with probiotics alone or a combination of probiotics and enzymes can improve the ADG of early-weaned grazing yak calves. Supplementation with the combination of probiotics and enzymes had a stronger positive effect on growth and serum hormone levels, compared to the single-probiotic treatment with Bacillus licheniformis, providing a basis for the application of a combination of probiotics and enzymes.

Altitudinal Distribution Patterns of Phyllosphere Microbial Communities and Their Contribution to Silage Fermentation of Kobresia pygmaea Along the Elevation Gradient on the Tibetan Plateau.

The study aimed to reveal altitudinal distribution patterns of phyllosphere microbial communities and silage fermentation of Kobresia pygmaea along the elevation gradient on the Tibetan Plateau. The K. pygmaea was individually collected from 2,500, 3,000, 4,000, 4,500, and 5,000 m above sea level (a.s.l.) on the Tibetan Plateau and ensiled for 60 days, respectively. The phyllosphere bacterial diversity increased while fungal diversity decreased along the elevation gradient, and bacterial and fungal richness showed a unimodal distribution with peak abundance at 4,000 and 3,000 m a.s.l., respectively. After 60 days of ensiling, the bacterial and fungal community composition changed but did not exhibit clear altitudinal distribution patterns. All K. pygmaea underwent a weak fermentation indicated by pH above 5.0 and low ratio of lactic/acetic acid (LA/AA). The S5000 and S3000 showed the highest and lowest pH, respectively. Although Lactobacillus dominated S4000 after 60 days of ensiling, S4000 still exhibited poor fermentation quality as well as silages from the other four regions. The higher ammonia N concentrations in S3000 and S4000 than the other silages were consistent with the detectable butyric acid in S3000 and S4000. The silage fermentation of K. pygmaea collected from five regions exhibited poor fermentation quality, thereby inoculating lactic acid bacteria to K. pygmaea before ensiling is highly recommended to improve fermentation quality on the Tibetan Plateau.

The microbial communities and natural fermentation quality of ensiling oat (Avena sativa L.) harvest from different elevations on the Qinghai-Tibet Plateau.

Introduction: Ensiling whole-crop oat (Avena sativa L.) has attracted a growing interest in the Qinghai-Tibet Plateau. The study aimed to investigate the microbial community and chemical composition of fresh and ensiling oat harvested from six different elevations of the Qinghai-Tibet Plateau. Method: The oat (A. sativa L. cv. Qingyin No. 1) was planted in six different sites across Qinghai-Tibet Plateau (BM, Bomi County; BY, Bayi County; DZ, Dazi County; BR, Biru County; SC, Suo County; SN, Seni County), where the elevations were in the range of 2,800-4,500 m above sea level (a. s. l.). Oat was harvested at the milk stage and ensiled for 90 days. Results: The highest crude protein (CP) and lowest water-soluble carbohydrate (WSC) were observed in fresh oat of SN and BM, respectively, however, no distinct gradient trend in WSC and CP concentrations along the elevation gradient. The lowest LAB counts in fresh oat from the highest elevational regions of SN. After 90 days of ensiling, the pH in all oat silages was lower than 4.2, and silages from SC and SN showed a lower pH and butyric acid concentration, and higher lactic acid (LA) concentration than silages of other regions. The oat silage from BR showed the lowest LA concentration and the highest pH. The bimodal distributions of fungal and bacterial richness in fresh oat along the elevation gradient were observed, while the elevation gradients did not affect the fungal Shannon index in fresh oat. Dioszegia, Cladosporium, and Vishniacozyma were the prevalent fungal genus in fresh oat, while Wickerhamomyces, Candida, and Saccharomyces dominated the fungal communities of silages. Wickerhamomyces and Candida were the dominant genera in oat silages from BM and SC, respectively. Erwinia, Paenibacillus, Pseudomonas, Leuconostoc, and Exiguobacterium dominated the bacterial community of fresh oat, while Lactobacillus and Kosakonia were the dominant bacterial genus in oat silages. Pantoea was the most dominant bacterial genus in fresh oat from low-elevational regions (BM, BY, and DZ). Oat from SN exhibited the best fermentation quality although fresh oat of SN hosted the lowest LAB counts, indicating that high-efficient LAB might be present in fresh oat sampled from high altitudes.

Changes in Blood Metabolic Profiles Reveal the Dietary Deficiencies of Specific Nutrients and Physiological Status of Grazing Yaks during the Cold Season in Qinghai Province of China.

This study aimed to investigate the changes in the blood metabolic profiles of grazing yaks during the cold season to reveal their physiological status and seek the nutrients needed to be supplemented. Six castrated yaks (3 years old) with 166.8 kg (standard deviation = 5.3) of liveweight grazed in the Qinghai-Tibetan Plateau were used as experimental animals without supplementary feeding. Blood samples of each animal were collected in October and December 2015, and March 2016 for the analysis of serum biochemicals and metabolome. Results showed serum indices involved in protein metabolism in grazing yaks showed greater differences during the cold season than the metabolisms of energy or minerals. Cold stress in December had minor effects on the serum metabolic profiles of yaks compared with those in October. Yaks in October and December shared seven differential serum metabolites and enrichments of the "arachidonic acid metabolism" and "glycine, serine, and threonine metabolism" pathways compared with those in March caused by the shortage of feeds. Summarily, the nutrient deficiency would be influential on the physiological status of grazing yaks during the cold season, especially on the protein metabolism, which could be improved by supplementary feeds.

Draft genomes assembly and annotation of Carex parvula and Carex kokanica reveals stress-specific genes.

Kobresia plants are important forage resources on the Qinghai-Tibet Plateau and are essential in maintaining the ecological balance of grasslands. Therefore, it is beneficial to obtain Kobresia genome resources and study the adaptive characteristics of Kobresia plants on the Qinghai-Tibetan Plateau. Previously, we have assembled the genome of Carex littledalei (Kobresia littledalei), which is a diploid with 29 chromosomes. In this study, we assembled genomes of Carex parvula (Kobresia pygmaea) and Carex kokanica (Kobresia royleana) via using Illumina and PacBio sequencing data, which were about 783.49 Mb and 673.40 Mb in size, respectively. And 45,002 or 36,709 protein-coding genes were further annotated in the genome of C. parvula or C. kokanica. Phylogenetic analysis indicated that Kobresia in Cyperaceae separated from Poaceae about 101.5 million years ago after separated from Ananas comosus in Bromeliaceae about 117.2 million years ago. C. littledalei and C. parvula separated about 5.0 million years ago, after separated from C. kokanica about 6.2 million years ago. In this study, transcriptome data of C. parvula at three different altitudes were also measured and analyzed. Kobresia plants genomes assembly and transcriptome analysis will assist research into mechanisms of plant adaptation to environments with high altitude and cold weather.

Evaluating fermentation quality, in vitro digestibility and aerobic stability of a total mixed ration ensiled with different additives on Tibet plateau.

OBJECTIVE: To investigate the improvement in utilization efficiency of total mixed ration (TMR) on Tibetan plateau, TMR were ensiled with different additives. METHODS: A total of 150 experimental silos were prepared in a completely randomized design to evaluate the six treatments: i) control (without additive), ii) Lactobacillus buchneri (L. buchneri), iii) acetic acid, iv) propionic acid, v) 1,2-propanediol; and vi) 1-propanol. After 90 days of ensiling, silos were opened for fermentation quality and in vitro analysis, and then subjected to an aerobic stability test for 14 days. RESULTS: Treating with L. buchneri, acetic acid, 1,2-propanediol and 1-propanol decreased propionic acid contents and yeast number, whereas increased (p<0.05) pH, acetic acid and ethanol contents in the fermented TMR. Despite increased dry matter (DM) loss in the TMRs treated with 1,2-propanediol and 1-pronanol, additives did not affect (p>0.05) all in vitro parameters including gas production at 24 h (GP24), GP rate constant, potential GP, in vitro DM digestibility and in vitro neutral detergent fibre digestibility. All additives improved the aerobic stability of ensiled TMR to different extents. Specially, aerobic stability of the ensiled TMR were substantially improved by L. buchneri, acetic acid, 1,2-propanediol, and 1-propanol, indicated by stable pH and lactic acid content during the aerobic stability test. CONCLUSION: L. buchneri, acetic acid, 1,2-propanediol, and 1-propanol had no adverse effect on in vitro digestibility, while ensiling TMR with the additives produced more acetic acid and ethanol, subsequently resulting in improvement of aerobic stability. There is a potential for some fermentation boosting additives to enhance aerobic stability of fermented TMR on Tibetan plateau.

Effects of different additives on fermentation quality and aerobic stability of a total mixed ration prepared with local feed resources on Tibetan plateau.

To improve the utilization efficiency of total mixed ration (TMR) on Tibetan plateau, the effects of different additives on fermentation quality and aerobic stability of the ensiled TMR prepared with local feed resources were studied. A total of 150 experimental silos were prepared in a completely randomized design to evaluate the following treatments: (a) control; (b) Lactobacillus buchneri; (c) acetic acid; (d) propionic acid; (e) 1,2-propanediol; and (f) 1-propanol. After 90 days of ensiling, silos were opened for fermentation quality and in vitro parameters analysis, and then subjected to an aerobic stability test for 14 days. The acetic acid, 1,2-propanediol and 1-propanol treatments increased (p < .05) pH and acetic acid content, and lowered (p < .05) the lactic acid production in comparison to control. There were no statistically significant differences in in vitro digestibility parameters among the treatments. Treatments of acetic acid, 1,2-propanediol and 1-propanol substantially improved the aerobic stability of the ensiled TMR, as indicated by almost unchanged pH and lactic acid contents throughout the aerobic exposure test. These results indicated that acetic acid, 1,2-propanediol and 1-propanol had no adverse effect on in vitro digestibility and could be effective additives for enhancing the aerobic stability of ensiled TMR prepared on Tibetan plateau.

Genome sequence of Kobresia littledalei, the first chromosome-level genome in the family Cyperaceae.

Kobresia plants are important forage resources in the Qinghai-Tibet Plateau and are essential in maintaining the ecological balance of grasslands. Therefore, it is beneficial to obtain Kobresia genome resources and study the adaptive characteristics of Kobresia plants in the Qinghai-Tibetan Plateau. We assembled the genome of Kobresia littledalei C. B. Clarke, which was about 373.85 Mb in size. 96.82% of the bases were attached to 29 pseudo-chromosomes, combining PacBio, Illumina and Hi-C sequencing data. Additional investigation of the annotation identified 23,136 protein-coding genes. 98.95% of these were functionally annotated. According to phylogenetic analysis, K. littledalei in Cyperaceae separated from Poaceae about 97.6 million years ago after separating from Ananas comosus in Bromeliaceae about 114.3mya. For K. littledalei, we identified a high-quality genome at the chromosome level. This is the first time a reference genome has been established for a species of Cyperaceae. This genome will help additional studies focusing on the processes of plant adaptation to environments with high altitude and cold weather.

Determination of 17beta-oestradiol by fluorescence immunoassay with streptavidin-conjugated quantum dots as label.

A sensitive and selective method for the determination of 17beta-oestradiol by fluorescence immunoassay (FIA) was established on the basis of quantum dots (QDs) as label. The complex of biotin-labelled anti-rabbit IgG and strepavidin conjugated by quantum dots (QD-SA) was regarded as a probe in this system and the strepavidin-biotin system as signal amplification system. After optimising the conditions of the immunoreaction, such as the concentration of the reagent and the pH of the buffer solution, the linear range and the limit of detection of 17beta-oestradiol were 0.01-10,000ngml(-1) and 0.00542ngml(-1), respectively. This method was applied to determine oestradiol in water samples, with the percent recoveries in the range of 86-113%.