The bio‐surfactant mannosylerythritol lipid acts as a selective antibacterial agent to modulate rumen fermentation

Methyl‐mannosylerythritol lipid (MEL), a new sugar esterified lipid synthesized by Pseudozyma aphidis, was assessed for its functionality in modulating rumen fermentation and microbiota toward more propionate and less methane production. A pure culture study using rumen representatives showed that MEL selectively inhibited the growth of most Gram‐positive bacteria including Streptococcus bovis, ruminococci, and Fibrobacter succinogenes, but not Gram‐negative bacteria such as Megasphaera elsdenii, Succinivibrio dextrinosolvens, and Selenomonas ruminantium. A batch culture study revealed that MEL significantly decreased methane production in a dose‐dependent manner with accumulation of hydrogen, while propionate production was enhanced. A continuous culture (Rusitec) study confirmed all of these changes. A feeding study revealed that sheep fed a MEL diet showed an increased proportion of propionate, while proportions of acetate and butyrate were decreased without affecting total VFA level. These changes disappeared after cessation of MEL feeding. Based on these results, dietary application of MEL can favorably modify rumen fermentation in terms of the efficiency of dietary energy utilization.     

Detection of candidate polymorphisms around the QTL for fat area ratio to rib eye area on BTA7 using whole‐genome resequencing in Japanese Black cattle

In our previous study, we performed genome‐wide association study (GWAS) to identify the genomic region associated with Fat area ratio to rib eye area (FAR) and detected a candidate in BTA7 at 10–30 Mbp. The present study aims to comprehensively detect all polymorphisms in the candidate region using whole‐genome resequencing data. Based on whole‐genome resequencing of eight animals, we detected 127,090 polymorphisms within the region. Of these, 31,945 were located within the genes. We further narrowed the polymorphisms to 6,044 with more than five allele differences between the high and low FAR groups that were located within 179 genes. We subsequently investigated the functions of these genes and selected 170 polymorphisms in eight genes as possible candidate polymorphisms. We focused on SLC27A6 K81M as a putative candidate polymorphism. We genotyped the SNP in a Japanese Black population (n = 904) to investigate the effect on FAR. Analysis of variance revealed that SLC27A6 K81M had a lower p‐value (p = .0009) than the most significant SNP in GWAS (p = .0049). Although only SLC27A6 K81M was verified in the present study, subsequent verification of the remaining candidate genes and polymorphisms could lead to the identification of genes and polymorphisms responsible for FAR.     

The effect of cortisol administration on blood plasma immunoglobulin M (IgM) concentrations in masu salmon (Oncorhynchus masou)

Immunoglobulin M (IgM) is known as a main factor in the humoral immune system of teleosts. In the present study, the effect of cortisol on plasma IgM concentrations was investigated using a specific antibody to IgM in masu salmon (Oncorhynchus masou). Cortisol was orally administered each day for 2 weeks at a dose of 1 mg g⁻¹ in the diet, and for the following week the fish were fed a non-treated diet. Blood plasma samples were collected at 0, 1, 2 and 3 weeks after the initiation of treatment. Oral administration of cortisol elevated plasma cortisol concentrations to about 40 ng/ml for 2 weeks after administration and slightly reduced plasma IgM concentration; the suppression was statistically significant one week after the period of hormone administration. However, treatment with cortisol did not affect plasma concentrations of total protein or α1-protein, one of the major serum proteins, during the experimental period. These results indicate that cortisol specifically suppresses plasma IgM concentrations.     

Diurnal rhythm of serum steroid hormone levels in the Japanese whiting,Sillago japonica,a daily-spawning teleost

Ovarian developmental stages and serum steroid hormone levels were examined at six different times of day (0100, 0600, 1000, 1300, 1600, 2000 h) in a marine teleost, the Japanese whiting Sillago japonica, which has an asynchronous-type ovary containing oocytes at various stages of development and spawns every day during a period ranging up to three months. The largest oocytes in the ovaries at the active vitellogenic or post-vitellogenic stages were found between 0100 and 1300 h. Oocyte maturation indicated by germinal vesicle breakdown (GVBD) occurred at 1600 h, and ovulated oocytes were observed in the ovaries collected at 2000 h. These processes were accompanied by a significant daily change in serum steroid hormone levels. The serum level of estradiol-17β showed a peak in fish with mature oocytes sampled at 1600 h. In these fish, the second-largest oocytes in the ovaries were at the initial stage of vigorous vitellogenesis, the secondary yolk stage. Therefore the highest level of serum estradiol-17β was considered to be due to the second-largest oocytes. Testosterone levels remained low and constant throughout the experimental period. The serum levels of 17α,20β-dihydroxy-4-pregnen-3-one (17α,20β-diOHprog) peaked at 1600 h at which time all fish had mature oocytes. These results indicate that the Japanese whiting possesses a diurnal rhythm of oocyte development including vitellogenesis, oocyte maturation and ovulation, and further suggest that daily cycles in oocyte growth and maturation which simultaneously take place in an ovary are regulated by diurnal secretions of estradiol-17β and the maturation-inducing steroid, 17α,20β-diOHprog.     

Approachability and contact behavior of commercial dairy calves to humans

Calves (n = 106) on four dairy farms were observed for their approachability to humans. All calves experienced similar rearing conditions: Beginning individual pen, after birth until weaning at about 2 months, where they were housed individually and fed milk and a milk replacement; Late individual pen, after weaning until grouping at about 3.5 months, where they were housed individually and fed hay, silage and concentrate feed; Beginning group pen, after grouping until 5 months, where they were housed in groups of 2–5 animals and fed hay, silage and concentrate feed; later group pen, from 5 to 7 months. The number of calves that contacted an experimenter who stood in front of their pens for 10 min was recorded on 6 separate days over 3 months. Latency to touch and time spent in activities during touching such as sucking, licking, biting and rubbing were also measured. There were no significant differences in the latency to touch and the ratio of touch to non‐touch calves between the rearing conditions and the farms. The time spent touching was significantly affected by the interaction between the rearing condition and the farm (P < 0.01). In detail, the time spent sucking (P < 0.001) and licking (P < 0.01) was different between the rearing condition × farm variables. The proportion of calves that approached and touched the experimenter tended to be higher in the farms in which a stockperson worked longer inside and outside their pens (both ρ = 0.95, P = 0.051). These results were interpreted according to the perspectives of early positive reinforcement with food and the habituation process to humans existing nearby.     

Steroid-binding characteristics of sex hormone-binding globulin (SHBG) in carp, Cyprinus carpio

In this study, the binding characteristics of SHBG were investigated in carp by the combination of FPLC and steroid ELISA techniques. The results of this study suggest that almost all E₂ was bound to SHBG in the blood.     

Clinicopathological features of canine neuroaxonal dystrophy and cerebellar cortical abiotrophy in Papillon and Papillon-related dogs

Neuroaxonal dystrophy (NAD) was examined in two Papillon dogs and a mix breed dog between Papillon and Chihuahua. In addition, cerebellar cortical abiotrophy (CCA) in a Papillon dog, which had similar clinical and magnetic resonance imaging (MRI) features to those of NAD, was also investigated. The common clinical symptoms of all dogs affected with NAD and CCA, were pelvic limb ataxia and cerebellar ataxia including intention tremor, head tremor, and hypermetria in the early onset. These clinical signs were progressed rapidly, and two dogs with NAD were euthanized by owner's request and the other two died by aspiration pneumonia. MRI examinations and gross observations at necropsy revealed moderate to severe cerebellar atrophy in all cases of NAD and CCA. The most typical histological change of NAD was severe axonal degeneration with marked spheroid-formation in the dorsal horn of the spinal cords, the nuclei gracilis, cuneatus, olivalis and its circumference in the medulla oblongata. The spheroids were characterized as large eosinophilic or granular globes within the enlarged myelin sheaths, sometimes accompanied by moderate accumulation of microglias and/or macrophages. In contrast, such spheroid formation was minimal in the brain of CCA. In the cerebellum, mild to moderate loss of the Purkinje and granular cells were recognized in three dogs with NAD, whereas these changes were more prominent in a dog with CCA. Although the clinical signs and MRI findings relatively resembled between NAD and CCA, the histopathological features considered to be quite differ, suggesting distinct pathogenesis and etiology. Since both NAD and CCA are proposed as the autosomal recessive hereditary disorders, careful considerations might be needed for the breeding of Papillon and Chihuahua dogs.     

The g.841G>C SNP of FASN gene is associated with fatty acid composition in beef cattle

The objective of the current study is to evaluate the association between fatty acid composition and fatty acid synthase gene polymorphisms as responsible mutations. For this purpose, we selected seven previously reported single nucleotide polymorphisms (SNPs) in FASN gene, including one within promoter region (g.841G>C) and six non‐synonymous SNPs (g.8805C>T, g.13126C>T, g.15532A>C, g.16024A>G, g.16039C>T, g.17924A>G), and genotyped them in Japanese Black cattle. Genotyping results revealed that g.8805 C>T and g.17924 A>G were monomorphic loci. Genome‐wide association analysis including the other five SNPs revealed that only g.841G>C showed significant associations with the percentages of C14:0, C14:1, C16:1 and C18:1 at 5% genome‐wide significance level. In order to further evaluate the effect, we genotyped g.841G>C using additional three populations, including two Japanese Black populations and a Holstein cattle population. g.16024A>G was also genotyped and included in the analysis because it has been reported to be associated with fatty acid composition in Japanese Black cattle. In the result of analysis of variance, g.841G>C showed stronger effects on fatty acid percentage than those of g.16024A>G in all populations. These results suggested that g.841G>C would be a responsible mutation for fatty acid composition and contribute to production of high‐grade beef as a selection marker in beef cattle.     

New Terpenes from the Egyptian Soft Coral Sarcophyton ehrenbergi

Chemical investigations of the Egyptian soft coral Sarcophyton ehrenbergi have led to the isolation of compounds 1–3 as well as the previously reported marine cembranoid diterpene sarcophine (4). Structures were elucidated by comprehensive NMR and HRMS experimentation. Isolated compounds were in vitro assayed for cytotoxic activity against human hepatocarcinoma (HepG2) and breast adenocarcinoma (MCF-7) cell lines.