Transgene escape could lead to genetically modified rice establishing wild populations in the natural environment and competing for survival space with weeds.  However, whether the expression of the Bacillus thuringiensis (Bt) gene in rice will alter the relationship between transgene plants and weeds and induce undesirable environmental consequences are poorly understood.  Thus, field experiments were conducted to investigate the weed competitiveness and assess the ecological risk of transgenic Bt rice under herbicide-free and lepidopterous pest-controlled environments.  Results showed that weed–rice competition in the direct-sowing (DS) field was earlier and more severe than that in the transplanting (TP) field, which resulted in a significant decrease in biomass and yield in DS.  However, conventional Bt and non-Bt rice yield was not significantly different.  The weed number, weed coverage ratio, and weed diversity of conventional Bt rice were significantly higher than those of non-Bt rice at the early growth and mature stages, especially in DS plots, suggesting that Bt traits did not increase the weed competitiveness of transgenic rice and had no negative effect on weed diversity.  Grain yield and weed number varied between different hybrid rice lines, but those differences were insignificant between Bt and non-Bt rice.  The number of insects increased with the increase of weeds in hybrid rice plots, whereas the insect number and diversity did not display a significant difference between Bt and non-Bt rice.  Therefore, the ecological risk of transgenic Bt rice is comparable to non-Bt rice.

Topping is a cultivation method that is widely practiced due to the indeterminate growth character of cotton (Gossypium hirsutum L.).  Among the different methods of accomplishing topping, manual topping is common in the Yellow River Valley of China, although it is time- and labor-intensive.  The objective of this study was to characterize the responses of cotton to different topping treatments with respect to development, yield and quality.  This study included field experiments from 2015 to 2016 with three different topping methods: manual topping (MT), chemical topping (CT) using mepiquat chloride, and a non-decapitation treatment (NT).  We found that the plant height, the number of fruiting branches and the length of upper fruiting branches of cotton treated with CT were significantly lower than NT.  The chlorophyll content of cotton treated with CT was not significantly different from NT, but was higher than that of MT in the later season.  CT enhanced plant development with reduced endogenous gibberellic acid and abscisic acid contents, and the apical development of the main stem was inhibited.  Compared with MT, CT significantly increased the biomass of the vegetative parts.  Most importantly, there were no significant differences in the yield or fiber quality between MT and CT.  These findings suggested that CT, a simplified and effective topping method, could be utilized as an alternative in the Yellow River Valley of China.

Soil management practices affect rhizosphere microorganisms and enzyme activities, which in turn influence soil ecosystem processes. The objective of this study was to explore the effects of different nitrogen application rates on wheat (Triticum aestivum L.) rhizosphere soil microorganisms and enzyme activities, and their temporal variations in relation to soil fertility under supplemental irrigation conditions in a fluvo-aquic region. For this, we established a split-plot experiment for two consecutive years (2014–2015 and 2015–2016) in the field with three levels of soil moisture: water deficit to no irrigation (W1), medium irrigation to (70±5)% of soil relative moisture after jointing stage (W2), and adequate irrigation to (80±5)% of soil relative moisture after jointing stage (W3); and three levels of nitrogen: 0 kg ha^–1 (N1), 195 kg ha^–1 (N2) and
270 kg ha^–1 (N3).  Results showed that irrigation and nitrogen application significantly increased rhizosphere microorganisms and enzyme activities.  Soil microbiological properties showed different trends in response to N level; the highest values of bacteria, protease, catalase and phosphatase appeared in N2, while the highest levels of actinobacteria, fungi and urease were observed in N3.  In addition, these items performed best under medium irrigation (W2) relative to W1 and W3; particularly the maximum microorganism (bacteria, actinobacteria and fungi) amounts appeared at W2, 5.37×10⁷ and 6.35×10⁷ CFUs g^–1 higher than those at W3 in 2014–2015 and 2015–2016, respectively; and these changes were similar in both growing seasons.  Microbe-related parameters fluctuated over time but their seasonality did not hamper the irrigation and fertilization-induced effects.  Further, the highest grain yields of 13 309.2 and 12 885.7 kg ha^–1 were both obtained at W2N2 in 2014–2015 and 2015–2016, respectively.  The selected properties, soil microorganisms and enzymes, were significantly correlated with wheat yield and proved to be valuable indicators of soil quality.  These results clearly demonstrated that the combined treatment (W2N2) significantly improved soil microbiological properties, soil fertility and wheat yield on the Huanghuai Plain, China.

    The efficiency of hybrid rice seed production can be improved by increasing the percentage of exserted stigmas. To identify quantitative trait loci (QTLs) for this trait, we conducted QTL mapping using 75 chromosome segment substitution lines (CSSLs) developed from a cross between the donor parent, Xieqingzao B (XQZB), a maintainer line which has high stigma exsertion and the recurrent parent, Zhonghui 9308 (ZH9308), a restorer line which has low stigma exsertion. A total of nine QTLs (qSSE5, qSSE10, qSSE11, qDSE10, qDSE11, qTSE5, qTSE6, qTSE10, and qTSE11) for single stigma exsertion (SSE), dual stigma exsertion (DSE) and total stigma exsertion (TSE) were assessed in two environments (Hainan and Zhejiang). Six of these QTLs (qSSE10, qSSE11, qDSE10, qDSE11, qTSE10, and qTSE11) were found in both environments, while one QTL (qTSE6) was found in only Hainan, and two QTLs (qSSE5 and qTSE5) were found in only Zhejiang. The qSSE10, qSSE11, qDSE10, qDSE11, qTSE6, qTSE10, and qTSE11 alleles, which are derived from the parent XQZB, exhibited a positive additive effect. In contrast, the qSSE5 and qTSE5 alleles, which are derived from the parent ZH9308, exhibited a negative additive effect. The SSE, DSE and TSE traits were significantly correlated with each other in an environmentally dependent manner. These results indicated that the lines showing higher values for SSE were more likely to exhibit increased values for DSE, which would ultimately increase TSE. To evaluate the advantage of exserted stigmas for cross-pollination, single, dual and total stigma exsertion should be considered separately in future attempts at genetic improvement to achieve increased production of rice hybrid seeds. This study also provides information for fine mapping, gene cloning and particularly marker-assisted selection (MAS), on the latter and with an emphasis the phenotypic effects and implications of the QTLs for practical use in hybrid rice breeding.

The objective of this study was to evaluate the effects of low ambient temperature (LAT) and dietary vitamin C (VC) supplementation on pulmonary vascular remodeling (PVR) and the relative expression of hypoxia inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and its receptor 2 (VEGFR-2) mRNA of lungs in 21-d-old broilers. 400 1-d-old male Cobb broilers were assigned randomly to 4 treatments as follows for 21 d: 1) LAT and a basal diet; 2) LAT and a basal diet supplemented with 1 000 mg kg–1 VC (LAT+VC); 3) normal ambient temperature (NAT) and a basal diet; 4) NAT and a basal diet supplemented with 1 000 mg kg–1 VC (NAT+VC). Each treatment was composed of 10 replicates of 10 birds per replicate. Samples of lung were collected after the broilers were killed at d 21. LAT increased the ratio of vessel wall area to vessel total area (WA/TA, %) and mean media thickness in pulmonary arterioles (mMTPA, %) (P<0.05). Dietary VC supplementation decreased mMTPA (P<0.05), but had no effect on the WA/TA. LAT increased (P<0.05) the relative mRNA expression of HIF-1α, VEGF and VEGFR-2, while adding VC to the diet could decrease (P<0.05) their relative mRNA expression. A significant positive correlation existed between the level of VEGF mRNA expression and the value of WA/WT (P<0.05) or mMTPA (P<0.05). These results suggested LAT resulted in pulmonary vascular remodeling, and the increase of HIF-1α, VEGF and VEGFR-2 mRNA expression, and dietary VC supplementation can alleviate pulmonary vascular remodeling in broiler by affecting these gene expression.

Quality control and screening of active substances in traditional Chinese medicines have been performed using fingerprint analysis. The spectrum-effect relationship between chromatography fingerprints and efficacy of herbal drugs is considered as a potentially useful method for determining active ingredients in complex mixtures. The study was designed to develop a method for determining the bioactive components of a compound Chinese medicine called Tiefeng based on spectrum-effect relationships between high-performance liquid chromatography (HPLC) fingerprints and anticoccidial activities. Four peaks of the established HPLC fingerprint indicate the main bioactive components of this medicine. In addition, pharmacodynamic atlas was defined and used to assess the anticoccidial activity of Tiefeng from different sources for the first time. We found that the level of anticoccidial activity of Tiefeng was consistent with the degree of similarity between the pharmacodynamic atlas and chromatogram of any sample. Furthermore, effect of this medicine was related with the main active constituents, along with the origin and the harvesting time.

Maedi-visna virus (MVV) is an ovine lentivirus that is widespread in many countries worldwide. Both clinical and subclinical MVV infections cause substantial economic losses. MVV infection in live sheep is usually diagnosed serologically, with antibody-positive sheep being regarded as infected. There have been few reports of maedi-visna in China, with no detailed epidemic analysis of MVV infection in ovine herds. In order to investigate the seroprevalence and spatial distribution of maedi-visna among ovine flocks in China, a total of 672 serum samples were collected from different ovine flocks in 12 regions (provinces, autonomous regions or municipalities) of China in 2011, and serum antibody levels were determined using a commercial ELISA Kit. This study represents the first investigation of the seroepidemiology of maedi-visna in China, indicating a circulation of MMV among sheep.

The β-1,3-glucan from yeast has been extensively examined for its immuno-enhancing effects in animals. However, investigation on the relationship among β-glucan, gut microbiota and immune-modulating effects remains limited particularly in pigs. Considering the critical roles of gut methanogens in the microbial fermentation, energy metabolism and disease resistance, we investigated the phylogenetic diversity of methanogens from fermented cultures of porcine colonic digesta with (G) or without (N) yeast β-glucan based on sequences of the archaeal 16S rRNA gene. A total of 145 sequences in the G library were assigned into 8 operational taxonomic units (OTUs) with the majority of sequences (114/145) related to strains Methanobrevibacter millerae or Methanobrevibacter gottschalkii with high identities ranging from 97.9 to 98.6%, followed by 23 sequences to Methanobrevibacter ruminantium, 2 sequences to Methanobrevibacter smithii and one sequence to Methanobrevibacter wolinii. The 142 sequences in the N library were assigned to 2 OTUs with most sequences (127/142) related to strains M. millerae or M. gottschalkii with sequence identities ranging from 97.9 to 98.5%, and 15 sequences related to M. gottschalkii with 97.9% identity. Shannon diversity index showed that the G library exhibited significantly higher archaeal diversity (P<0.05) and Libshuff analysis indicated the differences in the community structure between the two libraries were significant (P<0.0001). In conclusion, the current study provides evidence that addition of yeast β-glucan significantly increased the diversity of methanogens in in vitro fermented porcine colonic digesta.

A rapid, sensitive and specific ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC-MS) method was developed for the analysis of tetracycline antibiotics, including tetracycline (TC), oxytetracycline (OTC), chlortetracycline (CTC) and their 4-epimers (4-epiTCs) in agricultural soil fertilized with swine manure. Soil samples were extracted and cleaned-up with 10 mL EDTA-McIlvaine buffer solution (pH 4.0), then cleaned-up and pre-concentrated using the Oasis MAX cartridge and then eluted with 1 mL solution by mixing formic acid, methanol and water at a ratio of 2:15:83 (v/v/v). The purified samples were separated by an ACQUITY UPLC BEH C18 column using acetonitrile and water containing 0.1% formic acid mobile phase and detected by a single quadrupole MS. The limits of detection for the soil extraction method (LODsoil) ranged from 0.6-2.5 μg kg-1 with recoveries from 23.3-159.2%. Finally, the method was applied to an agricultural field in an area with intensive pig-fattening farming. Tetracyclines were detected in soil from 2.8 to 42.4 μg kg-1 soil. These results demonstrate that soil from swine farms can become severely contaminated with tetracycline antibiotics and their metabolites.

To investigate the tissue deposition and elimination of melamine (MEL) in broilers, a total of 1 920 commercial 1-d-old male Cobb broilers were randomly allotted to 6 treatments with diets contaminated by MEL at 0, 2, 10, 30, 50, 100 mg kg-1 of diet for 42 d, and followed MEL withdrawal from diet at 50 or 100 mg kg-1 of diet for 96 h. The MEL was found in residue of plasma, liver, kidney, breast, and leg muscle with the highest level in kidney and in dose response manner (except in kidney), but no time response (except in plasma). The MEL residue in organ tissue was below the safe level of 50 μg mL-1 in blood or 50 μg kg-1 in tissues proposed by the US FSIS when MEL in diet was lower (2 mg kg-1). The MEL in tissues was eliminated by withdrawal MEL from diets. The elimination half-life of MEL was from 3.2 to 6.6 h, and the clearance time, when MEL residue concentration under limit detection, was from 18.0 to 31.4 h.