This study aimed to investigate the dose-effect of iron on growth performance, antioxidant function, intestinal morphology, and mRNA expression of jejunal tight junction protein in 1- to 21-d-old yellow-feathered broilers.  A total of 720 1-d-old yellow-feathered male broilers were allocated to 9 treatments with 8 replicate cages of 10 birds per cage.  The dietary treatments were consisted of a basal diet (contained 79.6 mg Fe kg^–1) supplemented with 0, 20, 40, 60, 80, 160, 320, 640, and 1,280 mg Fe kg^–1 in the form of FeSO₄·7H₂O.  Compared with the birds in the control group, birds supplemented with 20 mg Fe kg^–1 had higher average daily gain (ADG) (P<0.0001).  Adding 640 and 1,280 mg Fe kg^–1 significantly decreased ADG (P<0.0001) and average daily feed intake (ADFI) (P<0.0001) compared with supplementation of 20 mg Fe kg^–1.  Malondialdehyde (MDA) concentration in plasma and duodenum increased linearly (P<0.0001), but MDA concentration in liver and jejunum increased linearly (P<0.05) or quadratically (P<0.05) with increased dietary Fe concentration.  The villus height (VH) in duodenum and jejunum, and the ratio of villus height to crypt depth (V/C) in duodenum decreased linearly (P˂0.05) as dietary Fe increased.  As dietary Fe increased, the jejunal relative mRNA abundance of claudin-1 decreased linearly (P=0.001), but the jejunal relative mRNA abundance of zona occludens-1 (ZO-1) and occludin decreased linearly (P˂0.05) or quadratically (P˂0.05).   Compared with the supplementation of 20 mg Fe kg^–1, the supplementation of 640 mg Fe kg^–1 or higher increased (P˂0.05) MDA concentrations in plasma, duodenum, and jejunum, decreased VH in the duodenum and jejunum, and the addition of 1,280 mg Fe kg^–1 reduced (P˂0.05) the jejunal tight junction protein (claudin-1, ZO-1, occludin) mRNA abundance.  In summary, 640 mg of supplemental Fe kg^–1 or greater was associated with decreased growth performance, increased oxidative stress, disrupted intestinal morphology, and reduced mRNA expression of jejunal tight junction protein.

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.

The development of skeletal muscle are complicated processes involving genes responsible for proper muscle morphology, contractility, cell proliferation, differentiation, interactions, migration, and death. The three-dimensional chromatin architecture of skeletal muscle development has not been studied intensively although dynamic transcriptional regulation during differentiation of muscle cells is one of the most deeply studied processes. The RNA-seq was used to analyze the transcriptome pattern during chicken muscle development across 12 stages. Hi-C was used to build a chromatin architectures during four representative stages. ChIP-seq was conducted to identify enhancers in these four stages, which are occupied by histone H3K27ac and H3K4me3 peaks. Results show that large-scale genome architecture changes are mostly unidirectional, and coupled by complex on/off dynamic patterns of gene expression. Specifically, we observed 258.30 Mb of the genome undergoing A/B compartment switching. Notable alterations (316.57 Mb) of interaction frequencies within TADs were observed. Substantial aging-associated genes exhibited ascending connectivity with the compartment transition from repressive to active status during muscle development. Some muscle-related gene promoters that interacted with active enhancers during development, and some myopathy/aging-associated genes that were activated in aging muscle were founded. These results provide key insights into skeletal muscle development in vivo, and offer a valuable resource that allows in-depth functional characterization of candidate genes.