Luteinizing hormone receptor number and affinity in corpora lutea from prepuberal gilts induced to ovulate and spontaneous corpora lutea of mature gilts     

C E Estienne  G B Rampacek  R R Kraeling  M J Estienne  C R Barb 《Journal of animal science》1988,66(4):917-922

This study was designed to determine if luteal cell receptors for luteinizing hormone/human chorionic gonadotropin (LH/hCG) contribute to the previously demonstrated abnormal function of induced corpora lutea (CL) in gilts. Twenty-five prepuberal (P) gilts, induced to ovulate with 1,500 IU pregnant mare serum gonadotropin followed 72 h later with 500 IU hCG (d 0 = day of hCG), and 22 mature (M) gilts that had displayed two or more estrous cycles were ovariectomized (OVX) on d 10, 14, 18, 22 or 26 after the onset of estrus. All gilts except those OVX on d 10 were hysterectomized between d 6 and 9 to ensure luteal maintenance. The CL were stored at -196 degrees C until determination of LH/hCG receptor number and dissociation constant (KD) by saturation analysis. Receptor number was greater for M than for P gilts on d 14 (P less than .07) and d 18 (P less than .01). The KD was greater in M than in P gilts on d 14 (P less than .01) and d 18 (P less than .0001). The LH/hCG receptor number and KD of P gilts remained the same throughout the days studied. The LH/hCG receptor number (fmol/mg protein) of M gilts was elevated on d 10, 14, and 18 (50.8, 50.4 and 51.4, respectively) and decreased on d 22 (26.5) and d 26 (25.4) to values similar to those of P gilts. In M gilts, KD increased on d 14, remained high on d 18 and decreased on d 22. We suggest that abnormal function of induced CL in P gilts may be due to an elevated LH receptor number.  相似文献   

Sequential bacteriological observations in relation to cell-mediated and humoral antibody responses of cattle infected with Mycobacterium paratuberculosis and maintained on normal or high iron intake   总被引：3，自引：0，他引：3  

AWD LEPPER  CR WILKS†  M. KOTIW†  JT WHITEHEAD†  KS SWART† 《Australian veterinary journal》1989,66(2):50-55

Twenty calves were orally infected with Mycobacterium paratuberculosis before weaning. Ten of these plus 4 non-infected controls were maintained on elevated dietary iron intake from 6 to 33 months of age. During this time, in which the majority of animals were bred, the influence of increased dietary iron upon tests of cellular and humoral immune responsiveness to antigens of the organism were monitored. Results were examined in relation to the organism's capacity to multiply and infect up to 7 portions of the intestinal tract. No significant differences were detected in the degree of intestinal disease or pattern of faecal excretion of M. paratuberculosis in iron supplemented and non-supplemented cattle. Cutaneous delayed-type hypersensitivity (DTH) to johnin PPD developed at 1 month and in-vitro lymphocyte and immunostimulatory activity (LS) to this antigen at 2 months after infection. LS indices were significantly reduced in magnitude in iron-supplemented cattle (p less than 0.01). Most ELISA antibody responses were positive 10 to 17 months after infection and preceded the fewer number of CF responses by several months. Neither of the antibody tests was affected by elevated iron intake. Generally, complete or partial resistance to paratuberculosis was associated with sustained positive monthly LS tests (index greater than or equal to 2.0), whereas antibody levels tended to be sustained only in the more severely affected cattle. Although neither test system was affected by pregnancy the ELISA failed to detect a significant proportion of cattle chronically shedding M. paratuberculosis in faeces.  相似文献   

Role of leptin in modulating the hypothalamic-pituitary axis and luteinizing hormone secretion in the prepuberal gilt     

Barb CR  Barrett JB  Kraeling RR 《Domestic animal endocrinology》2004,26(3):201-214

Three experiments (EXP) were conducted to test the hypothesis that leptin modulates LH, GnRH, and neuropeptide Y (NPY) secretion. In EXP I, prepuberal gilts received intracerebroventricular (i.c.v.) leptin injections and blood samples were collected. In EXP II, anterior pituitary cells from prepuberal gilts in primary culture were challenged with 10(-14), 10(-13), 10(-12), 10(-11), 10(-10), 10(-9), 10(-8), 10(-7), or 10(-6) M leptin individually or in combinations with 10(-10), 10(-9), and 10(-8) M GnRH. In EXP III, hypothalamic-preoptic area (HYP-POA) explants were placed in perfusion system and exposed to 0 (n=5), 10(-12) M (n=4), 10(-10) M (n=4), 10(-8) M (n=4), or 10(-6) M (n=5) human recombinant leptin (LEP) for 30 min. In EXP I, serum LH concentrations were unaffected by leptin treatment. In EXP II, all doses of leptin increased LH secretion except for 10(-12) and 10(-7) M. Only 10(-7), or 10(-13) M leptin in combination with 10(-8) or 10(-9) M GnRH, respectively, suppressed LH secretion. In EXP III, prior to leptin, media GnRH concentrations were similar across treatments. Media GnRH concentrations increased after 10(-12), 10(-10), and 10(-8) M leptin compared to control. Leptin treatment failed to influence NPY secretion across treatments. These results indicate that components of the neuroendocrine axis that regulate GnRH and LH secretion are functional and leptin sensitive before the onset of puberty. Other neural peptides in addition to NPY may mediate the acute effects of leptin on the GnRH-LH system and lastly, the inability of i.c.v. leptin treatment to increase LH secretion may in part be related to stage of sexual maturation and associated change in negative feedback action of estradiol on LH secretion.  相似文献   

Increased porcine circovirus type 2 replication in porcine leukocytes in vitro and in vivo by concanavalin A stimulation     

Lefebvre DJ  Meerts P  Costers S  Misinzo G  Barbé F  Van Reeth K  Nauwynck HJ 《Veterinary microbiology》2008,132(1-2):74-86

Previously, it was shown that modulation of the immune system enhances porcine circovirus type 2 (PCV2) replication in pigs. In the present study, the effect of the mitogen concanavalin A (ConA) on PCV2 replication was investigated. Since ConA induces T-lymphocyte activation and initiates the production of interferon-gamma (IFN-gamma), a cytokine that enhances PCV2 replication in porcine epithelial and monocytic cell lines in vitro, it was examined if the effects observed with ConA were mediated by IFN-gamma. In an in vitro study, ConA but not IFN-gamma enhanced PCV2 replication in peripheral blood mononuclear cells (PBMC). Up to 2.08% and 0.96% of PBMC were antigen positive for PCV2 strains 1121 and Stoon-1010, respectively, and a low virus production was observed. PCV2-infected PBMC were identified as CD4(+) (40%), CD8(+) (54%) and IgM(+) (11%). In a subsequent in vivo study, caesarean-derived colostrum-deprived piglets were injected with ConA or IFN-gamma 12h before inoculation and every 3 days for 9 days after inoculation with strain 1121. PCV2 was isolated from inguinal lymph node biopsies from 10 days post-inoculation (dpi) in ConA-treated pigs and from 15dpi in non-treated and IFN-gamma-treated pigs. ConA increased PCV2 replication levels, but disease was not observed. Half of the ConA-treated and IFN-gamma-treated pigs showed a delayed humoral immune response, but this delay did not result in increased PCV2 replication in these pigs. These experiments demonstrated that ConA enhances PCV2 replication in PBMC in vitro and in lymphoid tissues in vivo.  相似文献   

Patterns of gene expression in pig adipose tissue: insulin-like growth factor system proteins, neuropeptide Y (NPY), NPY receptors, neurotrophic factors and other secreted factors     

Hausman GJ  Barb CR  Dean RG 《Domestic animal endocrinology》2008,35(1):24-34

Although cDNA microarray studies have examined gene expression in human and rodent adipose tissue, only one microarray study of adipose tissue from growing pigs has been reported. Total RNA was collected at slaughter from outer subcutaneous adipose tissue (OSQ) and middle subcutaneous adipose tissue (MSQ) from gilts at 90, 150, and 210 d (n=5 age(-1)). Dye labeled cDNA probes were hybridized to custom porcine microarrays (70-mer oligonucleotides). Gene expression of insulin-like growth factor binding proteins (IGFBPs), hormones, growth factors, neuropeptide Y (NPY) receptors (NPYRs) and other receptors in OSQ and MSQ changed little with age in growing pigs. Distinct patterns of relative gene expression were evident within NPYR and IGFBP family members in adipose tissue from growing pigs. Relative gene expression levels of NPY2R, NPY4R and angiopoietin 2 (ANG-2) distinguished OSQ and MSQ depots in growing pigs. We demonstrated, for the first time, the expression of IGFBP-7, IGFBP-5, NPY1R, NPY2R, NPY, connective tissue growth factor (CTGF), brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF) genes in pig adipose tissue with microarray and RT-PCR assays. Furthermore, adipose tissue CTGF gene expression was upregulated while NPY and NPY2R gene expression were significantly down regulated by age. These studies demonstrate that expression of neuropeptides and neurotrophic factors in pig adipose tissue may be involved in regulation of leptin secretion. Many other regulatory factors were not influenced by age in growing pigs but may be influenced by location or depot.  相似文献   

Effects of IGF‐1 on In Vitro Culture of Bovine Preantral Follicles are Dose‐Dependent          下载免费PDF全文

CR Jimenez  JL de Azevedo  RG Silveira  J Penitente‐Filho  EL Carrascal‐Triana  AM Zolini  VR Araujo  CAA Torres  WG Gonçalves 《Reproduction in domestic animals》2016,51(3):435-444

This study aimed at assessing the effect of different concentrations of the growth factor similar to insulin 1 (IGF‐1) in the development, survival and ultrastructure of the bovine preantral follicles cultured in situ. Fragments of bovine ovarian cortical tissue were cultured during 1 and 7 days in 1 ml of α‐MEM⁺, supplemented with different concentrations of human recombinant IGF‐1 (0, 30, 70 and 100 ng/ml), in an incubator at 37°C and 5% of CO₂ in 24‐well plates with total replacement of the medium every 2 days. Non‐cultured ovarian fragments (control) and ovarian fragments cultured during 1 and 7 days were processed for classic histology, mechanical isolation and electron transmission microscopy (ETM). Parameters such as normality, viability, activation, development, diameter and ultrastructure were evaluated. All statistical analyses were carried out using sas Version 9.2. The results showed that the percentage of follicles morphologically normal in the IGF‐1 30 ng/ml treatment was similar to the fresh control (p > 0.05) both on the day 1 and on the day 7 of in vitro culture. In the viability analysis, the cultured treatments maintained the percentage of viable follicles during the entire culture period (p > 0.05). After 7 days of culture, the IGF‐1 30 ng/ml treatment showed higher percentages of developing follicles (48.33%) than those of the fresh control (22.22%) and the cultured treatments (p < 0.05). Also, after 7 days of culture, IGF‐1 30 ng/ml presented a higher follicular diameter when compared to the control and other concentrations of IGF‐1 tested. Ultrastructurally, the non‐cultured control and IGF‐1 30 ng/ml, after 7 days of culture, showed conserved oocytes, nuclei and organelles. Hence, it is concluded that IGF‐1 30 ng/ml was the most efficient concentration for the development of bovine preantral follicles cultured in vitro.  相似文献   

Autochthonous feline leprosy caused by Mycobacterium sp. strain Tarwin affecting a cat from the Central Coast of New South Wales          下载免费PDF全文

E Torii  G Reppas  MB Krockenberger  JA Fyfe  CR O'Brien  R Malik 《Australian veterinary journal》2016,94(8):285-289

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姬松茸深层发酵生产胞外多糖的碳氮源研究     

潘慧娟  吴应美  范雷法  Soccol CR  Pandey A 《中国食用菌》2006,25(2):44-46

研究表明摇床振荡培养有利于姬松茸菌丝体生长，而静止培养有利于其胞外多糖的合成。以胞外多糖为目标的研究中。为排除定粉类多糖（碳源）的干扰，红糖是比较理想的碳源，红糖的浓度以20g／L以内，酵母膏是较好的氮源。  相似文献   

Growth performance and adipose tissue deposition in barrows fed n-methyl-D,L-aspartate     

Estienne MJ  Douet WA  Harter-Dennis JM  Hartsock TG  Solomon MB  Barb CR 《Journal of animal science》2000,78(10):2504-2507

We previously reported that broilers fed n-methyl-D,L-aspartate (NMA) exhibited enhanced feed conversion efficiency and decreased percentage of fat in carcasses. In this experiment, growth performance and backfat thickness were evaluated in barrows fed NMA. Poland China x Yorkshire barrows weighing 68.8 +/- 1.7 kg (mean +/- SE) were allowed ad libitum access to feed containing NMA at levels of either 0 (n = 7), 100 (n = 6), 200 (n = 8), or 300 (n = 8) mg/kg for 36 d. Barrows were slaughtered at 99.5 +/- 2.3 kg BW. There was no effect (P > 0.1) of NMA on ADG or feed consumption. Gain:feed ratio decreased (P < 0.03) in a linear fashion with increasing level of NMA. There was a cubic effect (P < 0.05) of NMA treatment on first-rib backfat thickness. In response to graded levels of NMA, backfat thickness at the 10th rib (P < 0.08) and last rib (P < 0.03) increased in a linear fashion. The NMA had no effect (P > 0.1) on backfat thickness measured at the lumbar vertebra or longissimus muscle area measured at the 10th rib interface. The percentage of lean in the carcass decreased in a linear fashion (P < 0.05) in response to increasing levels of NMA in the diet. In summary, NMA had an overall negative effect on growth performance and carcass yield characteristics in barrows. The dichotomous effects of NMA on feed efficiency and body composition in poultry and swine warrants further scrutiny.  相似文献   

Serum concentrations of luteinizing hormone, growth hormone, testosterone, estradiol, and leptin in boars treated with n-methyl-D,L-aspartate     

Estienne MJ  Broughton DS  Barb CR 《Journal of animal science》2000,78(2):365-370

Three experiments were conducted to determine the effects of n-methyl-D,L-aspartate (NMA), an agonist of the excitatory amino acid glutamate, on secretion of hormones in boars. In Exp. 1, boars (185.0+/-.3 d of age; mean +/- SE) received i.v. injections of either 0, 1.25, 2.5, 5, or 10 mg of NMA/kg BW. There were no effects of NMA (P>.1) on secretion of LH and testosterone. Treatment with NMA, however, increased (P<.01) circulating GH concentrations in a dose-dependent manner. In Exp. 2, boars (401 d of age) received an i.v. challenge of NMA at a dose of 10 mg/kg BW or .9% saline. Treatment with NMA, but not saline (P>.1), increased serum concentrations of LH (P<.01), GH (P <.01), and testosterone (P<.06). In Exp. 3, boars that were 152, 221, or 336 d of age were treated i.v. with NMA (10 mg/kg BW). Across ages, treatment with NMA increased circulating concentrations of LH (P<.07) and testosterone (P<.01). However, NMA increased (P<.01) mean GH concentrations in only the oldest boars. Treatment with NMA had no effect (P>.1) on circulating concentrations of estradiol or leptin; however, estradiol concentrations increased (P<.03) with age. In summary, NMA increased secretion of LH, GH, and testosterone in boars. However, endocrine responses to treatment with NMA may be influenced by age of the animal. Finally, NMA did not influence circulating concentrations of estradiol or leptin.  相似文献