Effects of Lactobacillus formosensis S215T and Lactobacillus buchneri on quality and in vitro ruminal biological activity of condensed tannins in sweet potato vines silage.

AIMS: This study investigated the influence of two microbial inoculants; Lactobacillus formosensis and Lactobacillus buchneri on fermentation quality, chemical composition, aerobic stability and in vitro ruminal biological activity of condensed tannins in sweet potato vines silage. METHODS AND RESULTS: Sweet potato vines were ensiled for 28 and 60 days; without inoculant (CON), with Lact. buchneri (LB) or with Lact. formosensis (LF), both inoculants applied to achieve 1 × 106  CFU g-1 fresh forage. Lactobacillus formosensis silage had lower pH and higher lactic acid than all treatments. Yeasts and moulds were not detected in LB silage after ensiling. Lactobacillus buchneri silage was more aerobically stable than all treatments, whereas LF was more stable than CON silage. In vitro ruminal biological activity of condensed tannins was lower in microbial-inoculated silages than CON after ensiling. CONCLUSION: Lactobacillus formosensis improved fermentability by reducing silage pH and improved aerobic stability by producing more propionate, which inhibited yeast activity. Lactobacillus buchneri improved aerobic stability of the silage by producing more acetate. Both strains effectively reduced the antinutritional effect of condensed tannins after ensiling. SIGNIFICANCE AND IMPACT OF THE STUDY: Lactobacillus formosensis has the potential to be used as a silage inoculant because of its ability to improve fermentability and aerobic stability in sweet potato vines silage.

Vascular endothelial growth factor A improves quality of matured porcine oocytes and developing parthenotes.

Vascular endothelial growth factor is a multipotent angiogenic factor implicated in cell survival and proliferation. The objective was to determine effects of exogenous recombinant human VEGFA (or VEGFA165) in culture media on porcine oocyte maturation and parthenote development. Adding 5 ng/mL VEGFA to the culture medium improved the maturation rate of denuded oocytes (P < 0.05), although 5, 50, or 500 ng/mL did not significantly affect nuclear maturation of oocytes. Parthenotes from oocytes cultured either in in vitro maturation or in vitro culture medium supplemented with 5 or 50 ng/mL VEGFA had an improved blastocyst rate and increased total numbers of cells (P < 0.05). Moreover, those treated with 5 ng/mL of VEGFA had a higher hatched blastocyst rate (average of 121 cells per blastocyst). All VEGFA-treated oocytes had reduced apoptotic indices (P < 0.05), except for those with a higher dose (500 ng/mL) of VEGFA which had more apoptotic cells (P < 0.05). Adding 5 ng/mL VEGFA to oocytes during the last 22 h of in vitro maturation improved (P < 0.05) blastocyst rates and total numbers of cells, with reduced apoptosis indices similar to that of long-term (44 h) culture. Furthermore, Axitinib (VEGFR inhibitor) reversed the effects of VEGFA on parthenote development (P < 0.05). Follicular fluids from medium (2-6 mm) to large (>6 mm) follicles contained 5.3 and 7.0 ng/mL vascular endothelial growth factor protein, respectively, higher (P < 0.05) than concentrations in small (<2 mm) follicles (0.4 ng/mL). Also, VEGFA and its receptor (VEGFR-2) were detected (immunohistochemistry) in growing follicles and developing blastocysts. In addition, VEGFA inhibited caspase-3 activation in matured oocytes (P < 0.05). In conclusion, this is apparently the first report that VEGFA has proliferative and cytoprotective roles in maturing porcine oocytes and parthenotes. Furthermore, an optimal VEGFA concentration promoted porcine oocyte maturation and subsequent development.

Caecal transcriptome analysis of colonized and non-colonized chickens within two genetic lines that differ in caecal colonization by Campylobacter jejuni.

Campylobacter jejuni is one of the most common causes of human bacterial enteritis worldwide. The molecular mechanisms of the host responses of chickens to C. jejuni colonization are not well understood. We have previously found differences in C. jejuni colonization at 7-days post-inoculation (pi) between two genetic broiler lines. However, within each line, not all birds were colonized by C. jejuni (27.5% colonized in line A, and 70% in line B). Therefore, the objective of the present experiments was to further define the differences in host gene expression between colonized and non-colonized chickens within each genetic line. RNA isolated from ceca of colonized and non-colonized birds within each line was applied to a chicken 44K Agilent microarray for the pair comparison. There were differences in the mechanisms of host resistant to C. jejuni colonization between line A and line B. Ten times more differentially expressed genes were observed between colonized and non-colonized chickens within line B than those within line A. Our study supports the fact that the MAPK pathway is important in host response to C. jejuni colonization in line B, but not in line A. The data indicate that inhibition of small GTPase-mediated signal transduction could enhance the resistance of chickens to C. jejuni colonization and that the tumour necrosis factor receptor superfamily genes play important roles in determining C. jejuni non-colonization in broilers.