Domestic animal endocrinology最新文献

Synchronized cyclicity of replacement gilts is crucial to optimize breeding herd management, however, protocols with oral progestogen are expensive and require daily administration. This study tested two synchronization protocols without progestogens during the luteal phase in gilts. In Experiment I, on the day of the expression of the third estrus (D0), gilts were assigned to three groups (n = 6, each): control, with no treatment; PGF25: in which gilts received two doses of hCG (1,500 IU each) on D12 and D15 and two doses of a prostaglandin F2α (PGF) analogue (sodium cloprostenol; 250 µg) 6-h apart, on D25; and PGF30: in which gilts received two doses of hCG (1,500 IU each) on D12 and D15 and two doses of the PGF analogue (sodium cloprostenol; 250 µg) 6-h apart, on D30. The interval between PGF treatment and estrus expression was shorter in PGF30 than in PGF25 (P < 0.01). The PGF treatment failed to decrease serum progesterone (P4) for gilts from the PGF25 group (P > 0.05), but it was effective for gilts in the PGF30 group (P = 0.01). In Experiment II, gilts were assigned to three groups (n = 12, each): control (no treatment); eCG+hCG (400 IU eCG on D10 plus 500 IU hCG on D12); and hCG2 (two hCG doses, 1,500 IU each on D12 and D15). On D30, gilts from eCG+hCG and hCG2 that did not express estrus received two doses of the PGF analogue (250 µg each, 6-h apart). All gilts were inseminated when estrus was detected. Serum P4 concentrations were similar for all groups on D10 (P > 0.05) and greater on D20 and D25 for gilts in eCG+hCG and hCG2 (P < 0.01) than for those in the control, whereas P4 concentration was greater in hCG2 than in eCG+hCG, on both moments. The inter-estrus interval (IEI) was shorter for control gilts and intermediate for gilts in eCG+hCG, while the longest IEI was observed for gilts in hCG2 (P < 0.01). Total litter size was larger for gilts in the control (P = 0.02) compared to those in hCG2 and did not differ from the other groups for gilts in eCG+hCG (P > 0.05). In conclusion, Experiment I showed that PGF treatment did not induce luteolysis 10 days after the second hCG treatment but it was effective 15 days after the second hCG application. Additionally, Experiment II showed that both eCG+hCG and hCG2 were efficient in prolonging the luteal phase; however, number of piglets born alive and total litter size were negatively affected by the hCG2 protocol. In this sense, treatment with eCG+hCG or hCG2 may represent a steroid-free approach to prolong the luteal phase in gilts, although the doses and number of treatments must be further investigated.

The widespread use of silver nanoparticles (AgNPs) in consumer products and animal husbandry raises the need to study their impact on living organisms. This study was conducted on Hy-Line Brown hens at the age of 25 weeks with an average weight of 1.58 kg. Hens for 2 weeks received a solution of 50 nm AgNPs at a concentration of 100 pm (experimental group; n = 6) or a solution in which the nanoparticles were suspended (control group; n = 6). Thyroid hormones (thyroxine – T4, triiodothyronine – T3) were evaluated in the blood plasma and expression profiles of genes involved in thyroid hormone (TH) synthesis (TSHR, NIS, TPO, TG), metabolism (DIO1, DIO2, DIO3) and transport (MCT8, MCT10, LAT1) were determined in the chicken thyroid gland. Furthermore, iodothyronine deiodinase, TH transporter and TH receptor (THRA, THRB) mRNA expressions were evaluated in the livers isolated from the same chickens. AgNPs did not affect serum T₄ levels but elevated serum T₃ concentration. The results showed that AgNPs increased DIO3 mRNA in the thyroid gland. In turn, in the liver AgNPs administration significantly upregulated DIO2 and downregulated MCT10 mRNA levels. These results indicate that exposure to AgNPs leads to a tissue-specific alternative expression of genes engaged in TH metabolism. Moreover, the mRNA expression of DIO2 in the liver showed a positive correlation with plasma T₃ levels. In conclusion, AgNPs may have an impact on TH metabolism by affecting deiodinases and TH transporter MCT10 mRNA expression.

Anti-Müllerian hormone (AMH) has a conserved role in regulating the reproductive cycle in several species. Its circulating concentration reflects the size of the growing primordial follicle reserve and is a reliable predictor of superovulation response in embryo/oocyte donors. This study investigated the possible application of AMH measurement in dromedary camels (Camelus dromedarius) multiple ovulation embryo transfer programs. In experiment 1, the follicular cycle of synchronized and naturally cycling camels (n = 12) was monitored. Blood was collected at 6 timepoints in 2 consecutive cycles corresponding to emergence, mid-cycle, and dominance in both group and hormonal fluctuations were evaluated for repeatability of measurements within and between cycles. In experiment 2, the correlation between circulating AMH concentrations prior to initiation of superovulation and the outcome of superovulation was evaluated. The results were compared between donors with higher (n = 7) and lower than median (n = 8) AMH values. Mean AMH concentrations in synchronized and non-synchronized camels were 1.46 ± 0.15 and 0.95 ± 0.09, respectively. Intercycle and intracycle values of AMH showed high repeatability in camels of both groups (>96.4% and >92.74%, respectively) with significant correlations between values at different stages of the ovarian cycle (Emergence and mid-cycle: R² = 0.82; emergence and. dominance: R² = 0.86; Mid-cycle and dominance: R² = 0.93, P < 0.05). Total follicles, CLs, and recovered embryos were highly correlated with AMH values prior to superovulation (R² = 0.64, R² = 0.77, and R² = 0.64, respectively, P < 0.05). A greater number of developed follicles prior to mating (17.00 ± 2.09 vs. 7.62 ± 1.06), CLs (12.58 ± 1.36 vs. 5.12 ± 0.93), transferable (10.85 ± 1,31 vs. 3.37 ± 0.82), and spherical embryos (8.14 ± 1.07 vs. 2.62 ± 0.7) were observed in camels with higher than median concentrations of AMH (P < 0.05). Fluctuations in estradiol and progesterone did not affect variations in mean AMH values (r² < 0.19 and r² < 0.24, respectively, P > 0.05). In conclusion, highly consistent AMH values in dromedary camels are a reliable predictor of superovulation response and outcome in dromedary camels.

American Bison's wild nature limits blood sample availability to study its endocrinology. This report describes progesterone (P4) and estrone-sulfate (E1S) assays in American Bison feces using Liquid Chromatography coupled with Mass Spectrometry (LC-MS). In 2 ranches, samples of feces (n = 73) and serum (n = 93) were collected in pregnant and nonpregnant American Bison. Feces samples (250 mg) were extracted with methanol, purified, and concentrated. Then, feces and serum samples were assayed using LC-MS, according to our previously described technique. Fecal matrix homogeneity was determined by measuring steroids in different areas of the sample and concentration evolutions were evaluated after storage at room temperature. During the validation process, lower limits of quantification were 20 pg/g (E1S) and 4 ng/g (P4) by meeting the following criteria: relative standard deviation <15% and relative bias <15%. By measuring hormones in different spots from the same sample, a moderate variability for E1S (coefficient of variation [CV] up to 21.3%) and a high variability for P4 (CV up to 85.5%) were highlighted. Correlation between concentrations in feces and in serum was higher for E1S (r = 0.77) than for P4 (r = 0.65) and P4 could be assayed in pregnant and nonpregnant animals whereas E1S was only present in pregnant. Feces storage at room temperature induced modification of steroid concentrations. The quantification of E1S and, at a lower level, of P4 in feces is an interesting alternative to serum assay to describe the pregnancy-related evolution of these steroids in American Bisons, with feces ideally stored frozen and mixed before the LC-MS procedures.

Recent research has suggested that different cattle breed types may respond differently to anabolic implant protocols of varying intensity. Therefore, the purpose of this research was to compare anabolic implant protocols in feedlot steers of 2 different breed types. Sixty steers were stratified by weight and breed in a 2 × 3 factorial design examining 2 different breeds: Angus (AN; n=38) or Santa Gertrudis influenced (SG; n=22), and 3 implant strategies: no implant (CON; n=20), a moderate intensity implant protocol (d0 implant: Revalor-G, d56 implant: Revalor-IS, d112 implant: Revalor-S; MI; n=20), or a high intensity implant protocol (d0 implant: Revalor-IS, d56 implant: Revalor-S, d112 implant: Revalor-200; HI; n=20). Steers were randomly placed into pens equipped with GrowSafe bunks to collect dry matter intake and feeding behavior. All animals were fed the same diet. Weight, chute score, exit velocity, serum, rectal temperature, hip height and 12th rib fat thickness were collected approximately every 28 d over a 196 d period. Serum urea nitrogen (SUN) was evaluated as well. Total average daily gain was increased (P < 0.0001) in both the HI and MI steers compared to the CON steers by 29.4% and 26%, respectively. A treatment × breed interaction was observed (P < 0.0001) for hip height, with AN-CON steers being shorter (P < 0.0007) than AN-HI, SG-CON, SG-MI, and SG-HI steers. A breed × treatment interaction was observed (P < 0.004) for chute score and rectal temperature, with SG-HI and SG-MI steers having increased chute scores (P < 0.001) when compared to AN-HI, AN-MI, AN-CON, and SG-CON throughout the course of the trial. Additionally, SG-HI and SG-MI steers had an increased rectal temperature (P < 0.004) compared to AN-HI, AN-MI, AN-CON, and SG-CON steers. A breed effect was observed (P = 0.002) for SUN with AN steers having increased (P = 0.002) SUN concentration compared to SG sired steers, in addition to a treatment effect (P < 0.0001), with CON steers having a higher (P < 0.0001) SUN concentration than MI and HI steers, regardless of breed. The MI implant protocol increased net return per head, on average, by $97.28, regardless of breed, while the HI implant protocol increased net return by only $80.84. Taken together, despite the cattle breed types responding differently to the different anabolic implant protocols at times, a moderate intensity anabolic implant protocol was optimal in this experiment for steers raised in a temperate climate.

The study aimed to evaluate the involvement of apigenin, microRNA (miR)-152, and their interrelationships in the control of basic ovarian granulosa cell functions. The effects of apigenin (0, 10, and 100 µg/mL), miR-152 analogues or miR-152 inhibitor, and their combinations with apigenin on porcine granulosa cells were examined. Expression levels of miR-152, viability, proliferation, apoptosis, steroid hormones, IGF-I, oxytocin, and prostaglandin E2 release were analyzed. Apigenin increased the expression of miR-152, cell proliferation, and estradiol release and reduced apoptosis, progesterone, and IGF-I output. MicroRNA-152 analogues promoted cell viability and proliferation, as well as the release of progesterone, IGF-I, oxytocin, and prostaglandin E2; however, it inhibited apoptosis and estradiol output. miR-152 inhibitor had the opposite effect. Moreover, miR-152 analogues suppressed the effect of apigenin on cell apoptosis and estradiol release. These observations 1) confirm the involvement of apigenin in the control of basic ovarian cell functions; 2) are the first demonstration of importance of miR-152 in the control of these functions; 3) show the ability of apigenin to promote miR-152 expression and the ability of miR-152 to modify apigenin effects on ovarian cells.

Hair cortisol concentration (HCC) is considered as an indicator for a minimally invasive assessment of long-term stress. In dairy cows, in addition to stress influences, changing physiological conditions during gestation and lactation (eg, due to varying energy requirements or fluctuating milk yield) may affect HCCs. Thus, the aim of our study was to investigate HCCs of dairy cows during different stages of lactation and to determine the relationship between milk production traits and hair cortisol levels. Samples of natural hair and regrown hair were collected from 41 multiparous Holstein Friesian cows at 100-d intervals from parturition to 300 d postpartum. All samples were analyzed for cortisol concentration and the association of HCC with milk productions traits was evaluated. Our results show that cortisol concentration in natural hair increased after parturition and was highest 200 d postpartum. Cumulative milk yield from parturition to 300 d showed moderate and positive correlation with HCC in natural hair at 300 d. There was a positive correlation between urea concentration in milk and cortisol levels in regrown hair at 200 d, and between somatic cell count in milk and HCC in natural and regrown hairs 200 d postpartum. Together, these findings suggest that physiological loads during lactation, eg, caused by metabolic stress and/or inflammation, may be associated with increased HCC levels. In addition, the results on hair color confirm previous findings in cattle that black hair has higher cortisol concentrations than white hair. Black hair therefore appears to be more suitable for hair cortisol analysis as it provides higher protection against photodegradation.

Progesterone (P4) has a pivotal role on female puberty attainment in most farm animals. However, there are no studies evaluating the effect of P4 treatment previously to boar exposure for puberty induction in gilts. Therefore, serum P4 concentration, estrus expression and reproductive performance after boar stimuli were evaluated in gilts intramuscularly treated with long-acting P4 before boar exposure. In Experiment I, prepubertal gilts received either 1 mL of saline (control) or intramuscular (I.M.) P4 treatment (150 mg, 300 mg or 600 mg; n = 6 per treatment). Serum P4 concentration for P4-treated gilts was greater than for control gilts for at least 8 d for P4300 and P4600 groups (P < 0.05), but greater until after 16 d only for those treated with 600 mg (P < 0.05). In Experiments II (prepubertal) and III (peripubertal), gilts received either saline (control) or 300 mg P4 I.M. and those showing estrus signs were artificially inseminated (AI), whereas gilts without estrus expression were culled. In prepubertal gilts (Exp. II), estrus expression rate did not differ (P < 0.05) for control (79.1%; n = 110) and P4-treated gilts (81.5%; n = 108). In peripubertal gilts (Exp. III), although estrus expression did not differ between control (77.6%; n = 106) and P4-treated (69.6%; n = 102) gilts (P > 0.05), P4-treated gilts presented longer (23.1 ± 1.4 days) interval from treatment to estrus expression than control gilts (17.1 ± 1.3 days; P < 0.05). In Experiments II and III, the proportion of culled gilts with ovarian structures consistent with normal estrous cycles, farrowing rate, and litter size did not differ between treatments (P > 0.05). In conclusion, I.M. treatment with 300 or 600 mg of long-acting P4 was efficient in maintaining high P4 concentrations in prepubertal gilts for at least 8 days. However, P4 treatment over this time interval did not benefit the reproductive performance of prepubertal and peripubertal gilts.

Recent studies have reported hormonal regulation of expression of fibrillin 1 (FBN1), the gene that encodes asprosin, in bovine theca cells, however, hormonal regulation of gene expression of FBN1 and the asprosin receptor, olfactory receptor 4M1 (OR4M1), has not been evaluated in granulosa cells (GC). This study was designed to characterize FBN1 and OR4M1 gene expression in GC during development of bovine dominant ovarian follicles, and to determine the hormonal regulation of FBN1 and OR4M1 mRNA expression in GC. GC FBN1 mRNA abundance was greater (P < 0.05) in medium (5.1–8 mm) estrogen inactive (EI) follicles than in large (>8.1 mm) or small (1–5 mm) EI follicles. In comparison, GC OR4M1 mRNA abundance was greater (P < 0.05) in small EI follicles than in large or medium EI follicles. Abundance of OR4M1 mRNA in GC of follicles collected on days 3 to 4 (early growth phase) and on days 5 to 6 (late growth phase) was similar, whereas FBN1 mRNA abundance was greater (P < 0.05) on days 5 to 6 vs days 3 to 4. Hormonal regulators for FBN1 mRNA abundance in cultured small-follicle GC were identified: TGFβ1 causing a 2.45-fold increase, WNT3A causing a 1.45-fold increase, and IGF1 causing a 65% decrease. Steroids, leptin, insulin, growth hormone, follicle stimulating hormone, fibroblast growth factor 9 and epidermal growth factor had no effect on FBN1 mRNA abundance. Abundance of OR4M1 mRNA in GC was regulated by progesterone with 3.55-fold increase, but other hormones did not affect GC OR4M1 mRNA abundance. Findings indicate that both FBN1 and OR4M1 gene expression are hormonally and developmentally regulated in bovine follicles, and thus may affect asprosin production and its subsequent role in ovarian follicular function in cattle.