Rice direct seeding has the significant potential to save labor and water, conserve environmental resources, and reduce greenhouse gas emissions tremendously.  Therefore, rice direct seeding is becoming the major cultivation technology applied to rice production in many countries.  Identifying and utilizing genes controlling mesocotyl elongation is an effective approach to accelerate breeding procedures and meet the requirements for direct-seeded rice (DSR) production.  This study used a permanent mapping population with 144 recombinant inbred lines (RILs) and 2 828 bin-markers to detect quantitative trait loci (QTLs) associated with mesocotyl length in 2019 and 2020.  The mesocotyl lengths of the rice RILs and their parents, Lijiangxintuanheigu (LTH) and Shennong 265 (SN265), were measured in a growth chamber at 30°C in a dark environment.  A total of 16 QTLs for mesocotyl length were identified on chromosomes 1(2), 2(4), 3(2), 4, 5, 6, 7, 9, 11(2), and 12.  Seven of these QTLs, including qML1a, qML1b, qML2d, qML3a, qML3b, qML5, and qML11b, were reproducibly detected in both years via the interval mapping method.  The major QTL, qML3a, was reidentified in two years via the composite interval mapping method.  A total of 10 to 413 annotated genes for each QTL were identified in their smallest genetic intervals of 37.69 kb to 2.78 Mb, respectively.  Thirteen predicted genes within a relatively small genetic interval (88.18 kb) of the major mesocotyl elongation QTL, qML3a, were more thoroughly analyzed.  Finally, the coding DNA sequence variations among SN265, LTH, and Nipponbare indicated that the LOC_Os03g50550 gene was the strongest candidate gene for the qML3a QTL controlling the mesocotyl elongation.  This LOC_Os03g50550 gene encodes a mitogen-activated protein kinase.  Relative gene expression analysis using qRT-RCR further revealed that the expression levels of the LOC_Os03g50550 gene in the mesocotyl of LTH were significantly lower than in the mesocotyl of SN265.  In conclusion, these results further strengthen our knowledge about rice’s genetic mechanisms of mesocotyl elongation.  This investigation’s discoveries will help to accelerate breeding programs for new DSR variety development.

This experiment was conducted to investigate the effects of live yeast and yeast cell wall polysaccharides on growth performance, rumen function and plasma lipopolysaccharides (LPS) content and immunity parameters of beef cattle.  Forty Qinchuan cattle were randomly assigned to one of four treatments with 10 replicates in each treatment.  The dietary treatments were: control diet (CTR), CTR supplemented with 1 g live yeast (2×10¹⁰ live cell g^–1 per cattle per day (YST1), CTR supplemented with 2 g live yeast per cattle per day (YST2) and CTR supplemented with 20 g of yeast cell wall polysaccharides (30.0%≤β-glucan≤35.0%, and 28.0%≤mannanoligosaccharide≤32.0%) per cattle per day (YCW).  The average daily gain was higher (P=0.023) and feed conversion ratio was lower (P=0.042) for the YST2 than the CTR.  The digestibility of neutral detergent fiber (P=0.039) and acid detergent fiber (P=0.016) were higher in yeast supplemented groups.  The acetic acid:propionic acid of the YST2 was lower compared with the CTR (P=0.033).  Plasma LPS (P=0.032), acute phase protein haptoglobin (P=0.033), plasma amyloid A (P=0.015) and histamine (P=0.038) were lower in the YST2 compared with the CTR.  The copies of fibrolytic microbial populations such as Fibrobacter succinogenes S85, Ruminococcus albus 7 and Ruminococcus flavefaciens FD-1 of the YST2 were higher (P<0.001), while the copies of typical lactate producing bacteria Streptococcus bovis JB1 was lower (P<0.001) compared with the CTR.  Little differences were observed between the CTR, YST1 and YCW in growth performance, ruminal fermentation characteristics, microbial populations, immunity indices and total tract nutrient digestibility.  It is concluded that the YST2 could promote fibrolytic microbial populations, decrease starch-utilizing bacteria, reduce LPS production in the rumen and LPS absorption into plasma and decrease inflammatory parameters, which can lead to an improvement in growth performance in beef cattle. 

This study was conducted to investigate the phylogenetic diversity of archaea in the rumen of adult and elderly yaks.  Six domesticated female yaks, 3 adult yaks ((5.3±0.6) years old), and 3 elderly yaks ((10.7±0.6) years old), were used for the rumen contents collection.  Illumina MiSeq high-throughput sequencing technology was applied to examine the archaeal composition of rumen contents.  A total of 92 901 high-quality archaeal sequences were analyzed, and these were assigned to 2 033 operational taxonomic units (OTUs).  Among these, 974 OTUs were unique to adult yaks while 846 OTUs were unique to elderly yaks; 213 OTUs were shared by both groups.  At the phylum level, more than 99% of the obtained OTUs belonged to the Euryarchaeota phylum.  At the genus level, the archaea could be divided into 7 archaeal genera.  The 7 genera (i.e., Methanobrevibacter, Methanobacterium, Methanosphaera, Thermogymnomonas, Methanomicrobiu, Methanimicrococcus and the unclassified genus) were shared by all yaks, and their total abundance accounted for 99% of the rumen archaea.  The most abundant archaea in elderly and adult yaks were Methanobrevibacter and Thermogymnomonas, respectively.  The abundance of Methanobacteria (class), Methanobacteriales (order), Methanobacteriaceae (family), and Methanobrevibacter (genus) in elderly yaks was significantly higher than in adult yaks.  In contrast, the abundance of Thermogymnomonas in elderly yaks was 34% lower than in adult yaks, though the difference was not statistically significant.  The difference in abundance of other archaea was not significant between the two groups.  These results suggested that the structure of archaea in the rumen of yaks changed with age.  This is the first study to compare the phylogenetic differences of rumen archaeal structure and composition using the yak model. 

Pig and poultry production in China had experienced considerable changes from 1960 to 2010.  The present study aimed to evaluate the effects of these changes on greenhouse gas emission inventories (expressed as CO₂ equivalent) from these two sectors.  The inventories included methane emissions from enteric fermentation, methane and nitrous oxide production from manure management.  The greenhouse gas emissions from these sources in 2010 in pig sector were 17, 62 and 21%, respectively, and that in poultry sector (including chicken, duck, goose and others) were 1, 18 and 81%, respectively.  Total CO₂ equivalent increased from 1960 to 2010 in both pig (11 582 to 55 564 Gg yr^–1) and poultry (1 497 to 14 873 Gg yr^–1) sectors.  Within poultry sector, emissions from chicken, duck, goose and others accounted for 74, 15, 11 and 0.01% in 2010, respectively.  However, during the last 50 years, these emissions continuously reduced when related to production of 1 kg of pork (8.01 to 1.14 kg kg^–1), poultry meat (1.19 to 0.37 kg kg^–1) and egg (0.47 to 0.33 kg kg^–1), which is mainly associated with the continuous improvement in production efficiency in all management systems.  These results provide benchmark information for Chinese authorities to develop appropriate policies and mitigation strategies to reduce greenhouse gas emissions from pig and poultry sectors.