Potential role of marine algae extract on 3T3-L1 cell proliferation and differentiation: an in vitro approach.

BACKGROUND: From ancient times, marine algae have emerged as alternative medicine and foods, contains the rich source of natural products like proteins, vitamins, and secondary metabolites, especially Chlorella vulgaris (C. vulgaris) contains numerous anti-inflammatory, antioxidants and wound healing substances. Type 2 diabetes mellitus is closely associated with adipogenesis and their factors. Hence, we aimed to investigate the chemical constituents and adipogenic modulatory properties of C. vulgaris in 3T3-L1 pre-adipocytes. RESULTS: We analysed chemical constituents in ethanolic extract of C. vulgaris (EECV) by LC-MS. Results revealed that the EECV contains few triterpenoids and saponin compounds. Further, the effect of EECV on lipid accumulation along with genes and proteins expressions which are associated with adipogenesis and lipogenesis were evaluated using oil red O staining, qPCR and western blot techniques. The data indicated that that EECV treatment increased differentiation and lipid accumulation in 3T3-L1 cells, which indicates positive regulation of adipogenic and lipogenic activity. These increases were associated with up-regulation of PPAR-γ2, C/EBP-α, adiponectin, FAS, and leptin mRNA and protein expressions. Also, EECV treatments increased the concentration of glycerol releases as compared with control cells. Troglitazone is a PPAR-γ agonist that stimulates the PPAR-γ2, adiponectin, and GLUT-4 expressions. Similarly, EECV treatments significantly upregulated PPAR-γ2, adiponectin, GLUT-4 expressions and glucose utilization. Further, EECV treatment decreased AMPK-α expression as compared with control and metformin treated cells. CONCLUSION: The present research findings confirmed that the EECV effectively modulates the lipid accumulation and differentiation in 3T3-L1 cells through AMPK-α mediated signalling pathway.

Physiological Roles of Adipokines, Hepatokines, and Myokines in Ruminants.

Since the discovery of leptin secreted from adipocytes, specialized tissues and cells have been found that secrete the several peptides (or cytokines) that are characterized to negatively and positively regulate the metabolic process. Different types of adipokines, hepatokines, and myokines, which act as cytokines, are secreted from adipose, liver, and muscle tissue, respectively, and have been identified and examined for their physiological roles in humans and disease in animal models. Recently, various studies of these cytokines have been conducted in ruminants, including dairy cattle, beef cattle, sheep, and goat. Interestingly, a few cytokines from these tissues in ruminants play an important role in the post-parturition, lactation, and fattening (marbling) periods. Thus, understanding these hormones is important for improving nutritional management in dairy cows and beef cattle. However, to our knowledge, there have been no reviews of the characteristics of these cytokines in beef and dairy products in ruminants. In particular, lipid and glucose metabolism in adipose tissue, liver tissue, and muscle tissue are very important for energy storage, production, and synthesis, which are regulated by these cytokines in ruminant production. In this review, we summarize the physiological roles of adipokines, hepatokines, and myokines in ruminants. This discussion provides a foundation for understanding the role of cytokines in animal production of ruminants.

Chemerin is a novel regulator of lactogenesis in bovine mammary epithelial cells.

Chemerin is a chemoattractant cytokine (chemokine) produced by adipocytes and hepatocytes; it regulates insulin sensitivity and adipocyte differentiation. The objective of this study was to investigate the effect of chemerin on the expression of genes related to lactogenesis and the regulators of chemerin signaling in a bovine mammary epithelial cell line (MAC-T). Two types of chemerin receptors, chemokine like-receptor 1 (CMKLR1) and chemokine (C-C motif) receptor-like 2 (CCRL2), were detected in cultured MAC-T cells, whereas chemerin was not detected. G protein-coupled receptor 1 (GPR1), another receptor of chemerin, was undetectable in MAC-T cells. Chemerin upregulated transcript expression of CMKLR1, CCRL2, and genes associated with fatty acid synthesis, glucose uptake, insulin signaling, and casein synthesis in MAC-T cells. Lactogenic hormones (insulin, growth hormone, and prolactin) downregulated the expression of CMKLR1 in MAC-T cells. Adiponectin suppressed CMKLR1 expression. TNF-α suppressed CMKLR1, but induced CCRL2 expression. These data suggest chemerin is a novel regulator of lactogenesis via its own receptor in bovine mammary epithelial cells.

Single Nucleotide Polymorphism in the Coding Region of Bovine Chemerin Gene and Their Associations with Carcass Traits in Japanese Black Cattle.

Chemerin, highly expressed in adipose and liver tissues, regulates glucose and lipid metabolism and immunity in these tissues in ruminants and mice. Our previous reports showed that chemerin is involved in adipogenesis and lipid metabolism in adipose tissue as an adipokine. The aim of the present study was to identify single nucleotide polymorphisms (SNPs) in the coding region of the chemerin gene and to analyze their effects on carcass traits and intramuscular fatty acid compositions in Japanese Black cattle. The SNPs in the bovine chemerin gene were detected in 232 Japanese Black steers (n = 161) and heifers (n = 71) using DNA sequencing. The results revealed five novel silent mutations: NM_001046020: c.12A>G (4aa), c.165GT (92aa), c.321 A>G (107aa), and c.396C>T (132aa). There was no association between 4 of the SNPs (c.12A>G [4aa], c.165GG [107aa], and c.396C>T) and carcass traits or intramuscular fatty acid compositions. Regarding the remaining SNP, c.276C>T, we found that cattle with genotype CC had a higher beef marbling score than that of cattle with genotype CT, whereas cattle with genotype CT had a higher body condition score (p<0.10). Further, cattle with genotype CC had significantly higher C18:0 content in their intramuscular fat tissue than that of cattle with genotype CT (p<0.05). On the other hand, cattle with genotype CT had significantly higher C14:0 and C16:0 content in their intramuscular fat tissue (p<0.05). Moreover, the number of individuals carrying the minor allele of c.276C>T SNP is small. It is suggested that the c.276C>T SNP of the chemerin gene has potential in cattle breeding using modern methods, such as marker assisted selection. So, further functional and physiological research elucidating the impact of the chemerin gene on bovine lipid metabolism including fatty acid synthesis will help in understanding these results.

Neurotensin enhances sperm capacitation and acrosome reaction in mice.

Neurotensin (NT) has multiple functions, ranging from acting as a neurotransmitter to regulating intestinal movement. However, its function in reproductive physiology is unknown. Here, we confirmed the expression and localization of NT receptors (NTR1) in mouse epididymal spermatozoa and investigated the effect of NT on sperm function. Sperm protein tyrosine phosphorylation, one of the indices of sperm capacitation, was facilitated dose-dependently by NT administration. In addition, the acrosome reaction was promoted in capacitated spermatozoa, and addition of a selective antagonist of NTR1 and NTR2 blocked the induction. Furthermore, intracellular calcium mobilization by NT addition was observed. This showed that NT was an accelerator of sperm function via its functional receptors. The presence of NT was confirmed by immunohistochemistry and its localization was observed in epithelia of the uterus and oviduct isthmus and ampulla, which correspond to the fertilization route of spermatozoa. The NT mRNA level in ovulated cumulus cell was remarkably increased by treatment with human chorionic gonadotropin (hCG). Using an in vitro maturation model, we analyzed the effects of FSH, epidermal growth factor (EGF), estradiol, and progesterone in NT production in cumulus cells. We found that FSH and EGF upregulated NT release and mRNA expression. Both FSH- and EGF-induced upregulation were inhibited by U0126, an MAPK kinase inhibitor, indicating that FSH and EGF regulate NT expression via a MAPK-dependent pathway. This evidence suggests that NT can act as a promoter of sperm capacitation and the acrosome reaction in the female reproductive tract.

Effects of growth hormone gene polymorphism on lipogenic gene expression levels in diaphragm tissues of Japanese black heifers.

Two SNPs, i.e. L127V and T172M, of bovine growth hormone (GH) causing the presence of GH gene haplotypes A, B, and C was previously shown to alter intramuscular fatty acid (FA) composition in Japanese Black (JB) heifers. To determine the SNP effect on somatotropic hormone concentration and lipogenesis, we measured plasma GH, insulin, and insulin-like growth factor-1 (IGF-1) concentrations. We also measured mRNA levels of fatty acid synthase (FASN), stearoyl-coA desaturase (SCD), and sterol regulatory element binding proteins-1 (SREBP-1) and FA composition in diaphragm tissues. Heifers with genotype CC had the lowest plasma insulin concentration and FASN and SCD mRNA levels among genotypes. FASN mRNA levels in haplotype A tended to positively correlate with saturated FA (SFA) content and negatively correlated with C18:2 and unsaturated FA (USFA) contents. SCD mRNA levels in haplotype A positively correlated with monounsaturated FA (MUFA) contents and negatively correlated with C18:0 content. They also tended to positively correlate with C16:1, C18:1, and USFA contents and USFA/SFA ratio and negatively correlate with SFA content. Taken together, GH gene polymorphism affects the lipogenic genes expression levels and their relationships with fatty acid compositions in diaphragm tissues of JB heifers at 31 months of age.

Chemerin Regulates Epithelial Barrier Function of Mammary Glands in Dairy Cows.

Epithelial barrier function in the mammary gland acts as a forefront of the defense mechanism against mastitis, which is widespread and a major disorder in dairy production. Chemerin is a chemoattractant protein with potent antimicrobial ability, but its role in the mammary gland remains unelucidated. The aim of this study was to determine the function of chemerin in mammary epithelial tissue of dairy cows in lactation or dry-off periods. Mammary epithelial cells produced chemerin protein, and secreted chemerin was detected in milk samples. Chemerin treatment promoted the proliferation of cultured bovine mammary epithelial cells and protected the integrity of the epithelial cell layer from hydrogen peroxide (H2O2)-induced damage. Meanwhile, chemerin levels were higher in mammary tissue with mastitis. Tumor necrosis factor alpha (TNF-α) strongly upregulated the expression of the chemerin-coding gene (RARRES2) in mammary epithelial cells. Therefore, chemerin was suggested to support mammary epithelial cell growth and epithelial barrier function and to be regulated by inflammatory stimuli. Our results may indicate chemerin as a novel therapeutic target for diseases in the bovine mammary gland.

Heat-Shock Proteins Gene Expression in Peripheral Blood Mononuclear Cells as an Indicator of Heat Stress in Beef Calves.

This study was conducted to investigate the effect of HS on HSPs gene expression in bovine PBMCs of beef calves in in vitro and in vivo models. In the in vitro experiment, blood samples were collected from the jugular vein of five beef calves (age: 174.2 ± 5.20 days, BW: 145.2 ± 5.21 kg). In the in vivo experiment, sixteen Korean native male beef calves (age: 169.6 ± 4.60 days, BW: 136.9 ± 6.23 kg) were exposed to ambient temperature for seven days (22 to 24 °C, relative humidity 60%; temperature-humidity index (THI) = 68 to 70) and subsequently to the temperature and humidity corresponding to the target THI level for 21 days (HS). For PBMC isolation, blood samples were collected every three days. In the in vitro model, the cell viability was significantly decreased in HS groups compared with the control group (p = 0.015). The expression of HSP70 (p = 0.022), HSP90 (p = 0.003) and HSPB1 (p = 0.026) genes was increased in the HS group in in vitro model. In the in vivo experiment, the HSP70 gene expression was increased after sudden exposure to HS conditions (severe THI levels; THI = 88 to 90), whereas HSP90 and HSPB1 showed no differences among the THI groups (p > 0.05). However, in the severe THI group, the HSP70 gene expression returned to normal range after six days of continuous HS. In conclusion, the HSP70 gene plays a pivotal role in protecting cells from damage and is sensitive to HS in immune cells compared with other HSP genes in in vitro and in vivo models. In addition, the in vivo models suggest that calves exhibit active physiological mechanisms of adaptation to HS after six days of continuous exposure by regulating the HSP70 gene expression.

Prostatic androgen-repressed message-1 as a regulator of adipocyte differentiation in the mouse.

Adipocyte differentiation is an important aspect in energy homeostasis. Although the regulation of adipocyte differentiation is relatively well understood, the underlying molecular mechanism remains unclear. In this study, subcutaneous and epididymal adipose tissues were used to study the differential expression of associated genes. We found that the expression level of mouse homologue of rat prostatic androgen-repressed message-1 (mPARM-1) gene was higher in subcutaneous, perirenal and mesenteric adipose tissues than in epididymal adipose tissue. In mouse subcutaneous, perirenal, and mesenteric adipose tissues, the expression level of this gene was higher in adipocytes than in non-adipocyte cells, i.e. stromal-vascular cells. Furthermore, mPARM-1 mRNA expression was up-regulated in subcutaneous, mesenteric, and epididymal adipose tissues of mice fed a high-fat diet compared to those fed a normal-fat diet. Expression level of mPARM-1 mRNA increased in the early stage of the chemically induced adipocyte differentiation, preceding the increase in peroxisome proliferator-activated receptor-gamma 2 (PPAR-gamma2) mRNA. Tumor necrosis factor-alpha (TNF-alpha), an inhibitor of adipocyte differentiation, reduced the expression of mPARM-1 mRNA in differentiated 3T3-L1 cells and subsequently down-regulated the expression of adipogenic genes, including PPAR-gamma2, leptin and adipogenin. Moreover, knockdown of mPARM-1 expression with siRNA reduced lipid accumulation and the expression levels of PPAR-gamma2 and adipocyte protein 2 mRNAs, which suggest that the degree of adipocyte differentiation of 3T3-L1 cells has been reduced. These results indicate that mPARM-1 might be involved in the regulation of fat accumulation and adipocyte differentiation.

Addition of Wakame seaweed (Undaria pinnatifida) stalk to animal feed enhances immune response and improves intestinal microflora in pigs.

This study was conducted to evaluate the effects of supplementation of Wakame seaweed stalks on the immunity and intestinal microflora of pigs. Three separate experiments were performed: Relatively young (start at 20-30 kg; Experiments 1 and 2) and fattening period (70 kg; Experiment 3). All pigs (including the control group) were fed the same commercial feed, free from antibiotic additives, but in the feed for the treatment groups, 1% seaweed powder was added. There were no group differences observed in daily weight gain and feed intake in Experiments 1 and 2 between groups; however, daily weight gain was significantly higher in the treatment group compared to the control group in Experiment 3. The percentage of peripheral blood natural killer cells of the treatment group was significantly higher than that of the control group in all experiments. Although addition of seaweed changed the gene expression of cytokine and toll-like receptors of the small intestinal Peyer's patches slightly, seaweed seems to alter intestinal microflora preferentially, for instance, there was an increase in Lactobacillus and a decrease of Escherichia coli observed. These results suggest that Wakame seaweed can be used as supplement for pig feed to improve the gut health and immunity of pigs.

Correlations between mitochondrial respiration activity and residual feed intake after divergent genetic selection for high- and low- oxygen consumption in mice.

The aims of the present study were to identify the differences between two mouse lines (high (H)- and low (L)-oxygen consumption) in terms of mitochondrial respiratory activity when GMP (glutamate, malate, and pyruvate) and succinic acid are used as substrates and to examine the relationship between mitochondrial respiration activity and feed efficiency in both lines. The average daily feed intake, feed conversion ratio (FCR), and residual feed intake (RFI) were significantly higher in the H than the L line. The correlation between FCR and RFI was significant (r = 0.60, p < 0.05). RFI was effective as an indicator of feed efficiency. When succinic acid was used as a substrate, mitochondrial respiration states 2-4, ACR, and proton leak were significantly higher in the H than the L line. When GMP was used as a substrate, respiration states 3 and 4 in the H line were significantly higher than those in the L line, and there were significant positive correlations between FCR and RFI and mitochondrial respiration states 2-4. The results indicated that selection for high or low OC changed the basal metabolic rates estimated from liver mitochondrial respiration activity and feed efficiency.

Comparative transcriptome analysis of rumen papillae in suckling and weaned Japanese Black calves using RNA sequencing.

The length and density of rumen papillae starts to increase during weaning and growth of ruminants. This significant development increases the intraruminal surface area and the efficiency of VFA (acetate, propionate, butyrate, etc.) uptake. Thus, it is important to investigate the factors controlling the growth and development of rumen papillae during weaning. This study aimed to compare the transcriptomes of rumen papillae in suckling and weaned calves. Total RNA was extracted from the rumen papillae of 10 male Japanese Black calves (5 suckling calves, 5 wk old; 5 weaned calves, 15 wk old) and used in RNA-sequencing. Transcript abundance was estimated and differentially expressed genes were identified and these data were then used in Ingenuity Pathway Analysis (IPA) to predict the major canonical pathways and upstream regulators. Among the 871 differentially expressed genes screened by IPA, 466 genes were upregulated and 405 were downregulated in the weaned group. Canonical pathway analysis showed that "atherosclerosis" was the most significant pathway, and "tretinoin," a derivative of vitamin A, was predicted as the most active upstream regulator during weaning. Analyses also predicted IgG, lipopolysaccharides, and tumor-necrosis factor-α as regulators of the microbe-epithelium interaction that activates rumen-related immune responses. The functional category and the up-regulators found in this study provide a valuable resource for studying new candidate genes related to the proliferation and development of rumen papillae from suckling to weaning Japanese Black calves.

Selection for high and low oxygen consumption-induced differences in maintenance energy requirements of mice.

Maintenance energy requirements (MER) of mice selected for high (H) or low (L) oxygen consumption (OC) were compared. Forty-four mice from H and L OC lines were weaned at 3 weeks and divided into four experimental groups: group A were sacrificed at 4 weeks; group B were fed ad libitum, and groups C and D were fed 2.8 and 2.4 g/day, respectively, from 4 to 8 weeks of age. Groups B-D were sacrificed at 8 weeks. Chemical components were estimated for all groups. MER was estimated using a model that partitioned metabolizable energy intake into that used for maintenance, and protein and fat deposition. The feed conversion ratio for the B group was significantly higher in the H than in the L line. Feed intake for metabolic energy content per metabolic body size was significantly also higher in the H line, whereas accumulated energy content per metabolic body size was significantly higher in the L line. MER of the H line was greater than that of the L line (P < 0.10). These results suggest that selection for H or L OC produced differences in chemical components, feed efficiency, and MER between the H and L lines.

Search for an index for the taste of Japanese Black cattle beef by panel testing and chemical composition analysis.

To search for an index for chemical composition related to superior taste in Japanese Black beef, we conducted panel tests and analyzed the chemical composition of seven beef brands. Thirty-five sirloin beefs from five heifers were used in this study, sold under seven beef brands graded as more than A4 on the Japanese Meat Grade scale. The chemical composition analyses assessed both raw and roasted meat, the latter of which was roasted under the same conditions as those used for the panel test. Results of the panel test and chemical composition analyses revealed that fatty acid composition, sugar content, adenosine triphosphage (ATP)-related compounds, amino acid composition and odor composition in the sirloin meat differed among beef brands. Furthermore, the correlations of chemical compositions between roasted and raw meat were significantly high. Sugar content and ATP-related compounds in roasted meat were significantly correlated with the item 'overall evaluation' of the panel test. ATP-related compounds, such as inosinic acid, carnosine and taurine, in roasted and raw meat were correlated significantly with the item 'umami intensity' of the panel test. These results suggest that the composition of these components is important for an index related to the overall evaluation of beef.

Effects of mycoplasmal pneumonia of swine (MPS) lung lesion-selected Landrace pigs on MPS resistance and immune competence in three-way crossbred pigs.

To clarify the genetic influence of mycoplasmal pneumonia of swine (MPS) lesion-selected Landrace (La) on MPS resistance and immune characteristics in three-way crossbred pigs (LaWaDa), the LaWaDa pigs were compared with the non-selected crossbred (LbWbDb) and purebred (La) pigs. The MPS lesion score in the three lines was as follows: La line < LaWaDa line < LbWbDb line, with significant differences among the lines. The proportions of myeloid cells and T cells were lower and higher, respectively, in the LaWaDa pigs compared with those in the other two lines. Messenger RNA (mRNA) expression of interleukin (IL)-6, IL-10, transforming growth factor-ß, and interferon-γ in peripheral blood was significantly increased after vaccination in the La and LaWaDa lines. IL-4 mRNA expression in the LaWaDa line was intermediate to the La and LbWbDb lines. Furthermore, principal component analysis for immune traits and MPS lesions was executed to clarify the characteristics of each pig line. These findings suggest that the immune responses in the three pig lines are genetically distinct and that MPS resistance and some immunity characteristics from the La line were transmitted to the three-way crossbred pigs.

Reduction in voltage-gated K+ currents in primary cultured rat pancreatic beta-cells by linoleic acids.

Free fatty acids (FFAs), in addition to glucose, have been shown to stimulate insulin release through the G protein-coupled receptor (GPCR)40 receptor in pancreatic beta-cells. Intracellular free calcium concentration ([Ca(2+)](i)) in beta-cells is elevated by FFAs, although the mechanism underlying the [Ca(2+)](i) increase is still unknown. In this study, we investigated the action of linoleic acid on voltage-gated K(+) currents. Nystatin-perforated recordings were performed on identified rat beta-cells. In the presence of nifedipine, tetrodotoxin, and tolbutamide, voltage-gated K(+) currents were observed. The transient current represents less than 5%, whereas the delayed rectifier current comprises more than 95%, of the total K(+) currents. A long-chain unsaturated FFA, linoleic acid (10 microm), reversibly decreased the amplitude of K(+) currents (to less than 10%). This reduction was abolished by the cAMP/protein kinase A system inhibitors H89 (1 microm) and Rp-cAMP (10 microm) but was not affected by protein kinase C inhibitor. In addition, forskolin and 8'-bromo-cAMP induced a similar reduction in the K(+) current as that evoked by linoleic acid. Insulin secretion and cAMP accumulation in beta-cells were also increased by linoleic acid. Methyl linoleate, which has a similar structure to linoleic acid but no binding affinity to GPR40, did not change K(+) currents. Treatment of cultured cells with GPR40-specific small interfering RNA significantly reduced the decrease in K(+) current induced by linoleic acid, whereas the cAMP-induced reduction of K(+) current was not affected. We conclude that linoleic acid reduces the voltage-gated K(+) current in rat beta-cells through GPR40 and the cAMP-protein kinase A system, leading to an increase in [Ca(2+)](i) and insulin secretion.

Utilization of digital differential display to identify differentially expressed genes related to rumen development.

This study aimed to identify the genes associated with the development of the rumen epithelium by screening for candidate genes by digital differential display (DDD) in silico. Using DDD in NCBI's UniGene database, expressed sequence tag (EST)-based gene expression profiles were analyzed in rumen, reticulum, omasum, abomasum and other tissues in cattle. One hundred and ten candidate genes with high expression in the rumen were derived from a library of all tissues. The expression levels of 11 genes in all candidate genes were analyzed in the rumen, reticulum, omasum and abomasum of nine Japanese Black male calves (5-week-old pre-weaning: n = 3; 15-week-old weaned calves: n = 6). Among the 11 genes, only 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2), aldo-keto reductase family 1, member C1-like (AKR1C1), and fatty acid binding protein 3 (FABP3) showed significant changes in the levels of gene expression in the rumen between the pre- and post-weaning of calves. These results indicate that DDD analysis in silico can be useful for screening candidate genes related to rumen development, and that the changes in expression levels of three genes in the rumen may have been caused by weaning, aging or both.

Mycoplasma pneumonia of swine (MPS) resistance and immune characteristics of pig lines generated by crossing an MPS pulmonary lesion selected Landrace line and a highly immune capacity selected Large White line.

To understand the influence of crossbreeding on Mycoplasma pneumonia of swine (MPS) resistance and immune characteristics, two crossbred lines were characterized. One crossbred line, LaWa, was generated by crossing the MPS pulmonary lesion selected Landrace line (La) and the highly immune-selected Large White line (Wa). The second crossbred line, LaWb, was generated by crossing the La line and the nonselected Large White line (Wb). The crossbred LbWb line (nonselected Landrace line × nonselected Large White line) and the La line were used as controls. The LaWa and LaWb lines had an intermediate level of MPS lung lesions between La and LbWb lines, although the difference was not statistically significant. After stimulation with sheep red blood cells (SRBCs), the LaWb and LaWa lines showed immune characteristics similar to that of the La line; the number of monocytes in peripheral blood increased, while B cells, T cells, secretion of SRBC-specific immunoglobulin G, and interleukin (IL)-13 decreased. Additionally, the number of natural killer (NK) cells and the expression of IL-4 and IL-17 were significantly higher in the LaWb and LaWa lines, respectively. These data suggested that crossbreeding of La and Wa lines resulted in the inheritance of some of the selected immune responses.

Immunogenic properties and mycoplasmal pneumonia of swine (MPS) lung lesions in Large White pigs selected for higher peripheral blood immune capacity.

Immunogenic properties and mycoplasmal pneumonia of swine (MPS) lung lesions were compared between the immunity-selected Large White line and the non-selected Large White line. The selected Large White line showed a higher level of pulmonary MPS lesions compared with the non-selected Large White line. Subsequent to vaccination, the percentage of natural killer cells and T cells (CD3(+) CD4(+) CD8(-) and CD3(+) CD4(-) CD8(+) T cells) were significantly increased in the non-selected line but remained unchanged in the immunity-selected Large White line. Secretion of Mycoplasma hyopneumoniae vaccine-specific immunoblogulin G and phagocyte activity in peripheral blood were significantly higher in the immunity-selected Large White line than in the non-selected line. Expression of interleukin (IL)-4 and IL-6 messenger RNA in hilar lymph nodes was significantly lower in the immunity-selected Large White line than in the non-selected line. However, expression of IL-10 in all immune tissues was significantly higher in the immunity-selected Large White line. These results suggest that the selection for high immunity was not effective in increasing resistance to MPS lung lesions.

Immunogenic properties of Landrace pigs selected for resistance to mycoplasma pneumonia of swine.

Mycoplasma pneumonia of swine (MPS) lung lesions and immunogenic properties were compared between a Landrace line that was genetically selected for reduced incidence of pulmonary MPS lesions, and a non-selected Landrace line. The MPS-selected Landrace line showed significantly lower degrees of pulmonary MPS lesions compared with the non-selected Landrace line. When changes in immunity before and after vaccination were compared, the percentage of B cells in the peripheral blood of the MPS-selected Landrace line was significantly lower than that of the non-selected line. Furthermore, the concentration of growth hormone and the mitogen activity of peripheral blood mononuclear cells in the MPS-selected Landrace line showed significantly (P < 0.05) lower increases after vaccination than the non-selected line. Conversely, the concentration of peripheral blood interferon (IFN)-γ and salivary immunoglobulin A (IgA) after Mycoplasma hyopneumoniae vaccination was significantly higher in the MPS-selected Landrace line than in the non-selected line. Gene expression of toll-like receptor (TLR)2 and TLR4 was significantly higher in the MPS-selected Landrace line in immune tissues, with the exception of the hilar lymph nodes. The present results suggest that peripheral blood IFN-γ, salivary IgA TLR2, and TLR4 are important immunological factors influencing the development of MPS lesions.