Effects of exogenous lactic acid bacteria and maize meal on fermentation quality and microbial community of Orychophragmus violaceus silage.

Orychophragmus violaceus is a local Brassicaceae in China, while most of it is directly mowed and discarded after the ornamental period. In order to develop forage resources, this study firstly evaluated the potential preservation of O. violaceus silage. O. violaceus was harvested at full-bloom stage, and ensiled without (CK) or with maize meal (Y5), lactic acid bacteria inoculant (Z) and compound additive (Y5Z) for 60 d. Results of chemical and microbiological analysis showed that a large amount of lactic acid was produced and the final pH value was below 4.1 in silages regardless of additive application. CK silage was well preserved as indicated by the low levels of dry matter loss and butyric acid content, and the predominant genus were identified as Enterococcus and Pediococcus. Y5 silage had potential health risks for humans and animals as seen by frequent occurrence of pathogenic bacteria Clostridium and Achromobacter. Z and Y5Z silages were poorly preserved, resulting in great dry matter loss and butyric acid content. Considering the abundant acetic acid production, the dominant Lactobacillus might possess a heterofermentative pathway in Z and Y5Z silages. In conclusion, O. violaceus has the potential to be long stored as silage because of its sufficient water-soluble carbohydrates, while exogenous lactic acid bacteria and maize meal generally provided little positive effect. In future research, efficient homofermentative Lactobacillus strains were suggested to be screened to further enhance the ensiling process of O. violaceus silage.

Effects of grazing mixed-grass pastures on growth performance, immune responses, and intestinal microbiota in free-range Beijing-you chickens.

There is an increasing interest in free-range poultry with the increasing focus on food safety and animal welfare. This study was conducted to evaluate the effects of grazing mixed-grass pastures on growth performance, immune responses, and intestinal microbiota in free-range laying chickens. Ten-week-old female Beijing-you chickens were blocked by the BW and randomly assigned to 3 free-range systems in poplar plantations for 120 d: forage-removed paddocks with a high stocking density of 5 m2/hen (control [CK]); mixed-grass pastures with a low stocking density of 6 m2/hen ;or mixed-grass pastures with a high stocking density of 5 m2/hen. Intestinal microbial community analysis was performed by 16S rRNA gene sequencing using Illumina MiSeq. The results revealed that no differences (P > 0.05) were found between the 3 raising systems for the BW and ADG. Chickens grazing mixed-grass pastures exhibited decreased (P > 0.05) mortality and improved immune responses as evidenced by increased T-lymphocyte proliferation (P > 0.05) and immunoglobulin A (P > 0.05) and immunoglobulin M concentrations (P < 0.05) compared with those raised in forage-removed paddocks. Metagenomic analysis indicated that grazing mixed-grass pastures regulated the intestinal microbiota by increasing the prevalence of beneficial bacteria, such as Lactobacillus, Bacteroides, and Faecalibacterium, and reducing potentially pathogenic bacteria population, such as the Rikenellaceae_RC9_gut_group compared with the CK. Therefore, this study indicated that grazing mixed-grass pastures could positively influence intestinal microbiota that may contribute to the overall growth and immunity of free-range chickens and that a low stocking density of 6 m2/hen was optimal to Beijing-you chickens grazing mixed-grass pastures.

Effects of dietary supplementation of alfalfa meal on growth performance, carcass characteristics, meat and egg quality, and intestinal microbiota in Beijing-you chicken.

This study was conducted to investigate the effects of alfalfa meal supplementation on growth performance, carcass characteristics, meat and egg quality, and intestinal microbiota in chickens. A total of 600 healthy 20-wk female Beijing-you chickens (a local Chinese chicken breed) were selected and randomly assigned into 4 dietary treatments: 0, 5, 8, and 10% alfalfa meal supplementation. Chickens were raised in a free-range system for 56 d. Microbiota inhabiting 3 different intestinal sections (duodenum, ileum, and cecum) was determined using high-throughput sequencing. The results showed that chickens given alfalfa meal had lower (P < 0.05) feed conversion ratio, mortality, abdominal fat yield, and yolk cholesterol content, and higher (P < 0.05) breast muscle contents of inosine monophosphate, total amino acids, essential amino acids, non-essential amino acids, delicious amino acids, yolk protein, albumen protein, and yolk color compared to those given no alfalfa meal. The Lactobacillus was the dominant genus in both duodenum and ileum, while the microbiota in cecum was mainly composed of the Bacteroides. Although small changes in the dominant intestinal microbiota of chickens fed with or without alfalfa meal were observed, supplementation of alfalfa meal tended to stimulate the proliferation of beneficial bacteria, such as the Lactobacillus and Bacteroides, and inhibit potential pathogens, including the Clostridium. Therefore, dietary supplementation of alfalfa meal was feasible to Beijing-you chickens raised in a free-range system, and 10% was recommended as the relatively optimal level.

Molecular cloning and functional characterisation of an H+-pyrophosphatase from Iris lactea.

Tonoplast H+-pyrophosphatases (VPs) mediate vacuolar Na+ sequestration, a process important for salt tolerance of plants. The function of VP in the highly drought- and salt-tolerant perennial Iris lactea under salt stress is unclear. Here, we isolated IlVP from I. lactea and investigated its function in transgenic tobacco. IlVP was found to comprise 771 amino acid residues and showed 88% similarity with Arabidopsis AtVP1. IlVP was mainly expressed in shoots and was up-regulated by salt stress. Overexpression of IlVP enhanced growth of transgenic tobacco plants compared with wild-type (WT) plants exposed to salt stress. Transgenic plants accumulated higher quantities of Na+ and K+ in leaves, stems, and roots under salt stress, which caused higher leaf relative water content and decreased cell membrane damage compared with WT plants. Overall, IlVP encoding a tonoplast H+-pyrophosphatase can reduce Na+ toxicity in plant cells through increased sequestration of ions into vacuoles by enhanced H+-pyrophosphatase activity.

Antioxidative systems, metal ion homeostasis and cadmium distribution in Iris lactea exposed to cadmium stress.

Iris lactea is a perennial halophyte and is tolerant to Cd. However, the mechanisms underlying this Cd tolerance are still poorly understood. In this study, morphological, physiological and biochemical responses of I. lactea to a 21 d exposure to different concentrations of Cd (0-150mgL-1) were investigated. I. lactea plants showed no toxicity symptoms except for a small reduction in growth at 100 and 150mgL-1 Cd, along with the enhancement of H2O2 and MDA content in comparison to the control. The activities of SOD and POD were significantly enhanced and Ca accumulated with increasing Cd concentrations. Moreover, most Cd was retained in roots and only a small amount was transported to the shoots with increasing external Cd concentrations. Cd content had a negative correlation with content of K, Fe, Zn, and Mn and a positive correlation with Mg content in shoots and roots, which had no influence on these contents of mineral nutrients in shoots and chlorophyll levels with the increase of Cd concentrations. The Cd translocation factors were always less than 1 and bioaccumulation factors ranged from 3.43 to 15.6 across all treatments, suggesting that I. lactea might be effectively used in phytostabilization of Cd contaminated soils. Overall, the findings suggest that I. lactea could reduce photoinhibition and oxidative damage and maintain metal ion homeostasis in plant tissue by limiting translocation of Cd from roots to shoots and enhancing induction of antioxidant enzyme activities, thereby improving its Cd tolerance.

Cloning and Transformation of EeHKT1;4 Gene from Elytrigia elongata.

The EeHKT1;4 gene was firstly cloned from Elytrigia elongata by RT-PCR technique with 1977 bp full-length cDNA encoding 1722 bp open reading frame (ORF) and 573 amino acids. The PCR fragment of EeHKT1;4 gene was inserted into the binary vector pBI121 and got the resulted expression vector, which named pBI121-35S-EeHKT1;4-Nos. The vector was further transformed into the agrobacterium EHA105, and then EeHKT1;4 gene was transferred into tobacco by the Agrobaterium- mediated genetic transformation method. The results showed that the target gene was inserted into the genomes of tobacco and expressed. Therefore, the transgenic tobacco (T0) plants overexpressing EeHKT1;4 gene were successfully obtained in this study. And EeHKT1;4 reduces Na+ concentration in the leaves of T0 plants, thereby plays a central role in protecting plant leaves from salinity stress.

Role of silicon in alleviating salt-induced toxicity in white clover.

To understand the role of silicon (Si) in alleviating sodium (Na) toxicity in Trifolium repens L. (white clover), the changes of biochemical and physiological parameters were investigated in four-week-old white clover seedlings exposed to 0 or 120 mM NaCl with or without 1.5 mM Si for 7 days. Results showed that added Si alone did not have any effects on the growth and Na⁺, K⁺ accumulations in white clover plants compared to the control (no added Si and NaCl). However, in the presence of NaCl, additional Si significantly enhanced the selective transport capacity for K⁺ over Na⁺ that contributed to reduced Na⁺ uptake and increased K⁺ uptake by roots, thereby improving its growth and K⁺/Na⁺ homeostasis in white clover. This study would provide a way for improving salt tolerance in important legume white clover forage.

Accumulation and tolerance characteristics of zinc in Agropyron cristatum plants exposed to zinc-contaminated soil.

In phytoremediation, plants are used to stabilize or remove toxins from soil. In this study, a pot experiment was conducted in a greenhouse to evaluate the phytoremediation potential of Agropyron cristatum (Poaceae) grown on Zinc (Zn) contaminated soils. Results indicated that Zn accumulation in both shoots and roots increased with soil Zn concentration, and Zn concentrations in roots were greater than in shoots. A significantly negative correlation was found between translocation factor or bioconcentration factor values and Zn concentrations in soil. Overall, A. cristatum was Zn excluder with an innate capacity to tolerate Zn stress and may have potential for the phytostabilization of sites contaminated with Zn.