Tissues Of Gilts Research Articles

Determination of ractopamine residue in tissues and urine from pig fed meat and bone meal

ABSTRACTIn many countries, ractopamine hydrochloride (RAC) is allowed to be used in animal production as a β-agonist, which is an energy repartitioning agent able to offer economic benefits such as increased muscle and decreased fat deposition, feed conversion improvement and an increase in average daily weight gain. However, some countries have banned its use and established strict traceability programmes because of pharmacological implications of β-agonist residues in meat products. In Brazil, commercial RAC is controlled (5–20 mg kg−1) and only added to pig diet during the last 28 days before slaughter. However, the control is more difficult when co-products, like meat and bone meal (MBM), which can be produced from RAC treated animals, are part of the feed composition. Therefore, a study was undertaken to evaluate the presence of RAC residue concentrations in urine and tissues of gilts (n = 40) in four dietary groups: 0%, 7%, 14% and 21% (w/w) of MBM-containing RAC (53.5 µg kg−1). The concentration of RAC residues in MBM, pig tissues and urine was determined by LC–MS. Low RAC concentrations were detected in muscle, kidney, liver and lungs (limit of detection = 0.15, 0.5, 0.5 and 1.0 µg kg−1, respectively); however, no RAC residues were quantified above the limit of quantification (0.5, 2.5, 2.5 and 2.5 µg kg−1, respectively). In urine, the RAC concentration remained below 1.35 µg L−1. These data suggest that MBM (containing 53.5 µg kg−1 RAC) added to diet up to 21% (w/w) could hamper the trade where RAC is restricted or has zero-tolerance policy.

347 Prolactin, prolactin receptor, and adiponutrin messenger RNA abundances in mammary extraparenchymal tissue of gilts are affected by body condition

347 Prolactin, prolactin receptor, and adiponutrin messenger RNA abundances in mammary extraparenchymal tissue of gilts are affected by body condition

Porcine circovirus type 2 DNA detection in the uterine tissue of gilts in relation to endometritis and the number of leukocyte subsets in the endometrium

The aim of the present study was to determine the prevalence of porcine circovirus type 2 (PCV2) DNA-positive uterine tissues in gilts in relation to endometritis and the number of leukocyte subsets in the endometrium. Uterine tissues from 32 Landrace × Yorkshire gilts were investigated. The gilts were classified according to both macroscopic and microscopic examination of the endometrium into three groups: normal (n = 13), acute endometritis (n = 11) and chronic endometritis (n = 8). Reproductive cycle was defined according to the ovarian appearance as follicular, luteal and inactive phases. PCV2 DNA was determined using polymerase chain reaction. The number of leukocyte subsets, including lymphocytes, neutrophils, eosinophils, macrophages and plasma cells, in the epithelium, subepithelium and glandular layer of the endometrium was carefully evaluated. It was found that PCV2 DNA was detected in 34.4 % (11/32) of the uteri. According to the lesion of endometritis, PCV2 DNA was detected in 53.9 % (7/13) of normal uteri, 36.4 % (4/11) of acute endometritis, and 0.0 % (0/8) of chronic endometritis (P = 0.038). The PCV2 DNA was detected in 55.0 % (5/9), 20.0 % (4/20) and 66.7 % (2/3) of tissues in follicular, luteal and inactive phases, respectively (P = 0.081). Leukocyte subsets in all tissue layers of the endometrium did not differ significantly between the uterine tissues with and without PCV2 DNA detection (P > 0.05). These findings indicate that PCV2 exists in the reproductive organs of the gilts. The PCV2 persistence can be a risk factor for transmission of the virus to negative sows and potentially cause reproductive failures. Nevertheless, the influence of PCV2 natural infection on the reproductive function of gilt still requires further investigation.

Prevalence of porcine circovirus-2 DNA-positive ovarian and uterine tissues in gilts culled due to reproductive disturbance in Thailand.

The present study aimed to determine the prevalence of porcine circovirus-2 (PCV-2) DNA-positive ovarian and uterine tissues in gilts culled due to reproductive disturbance in Thailand. Tissues (70 ovaries and 102 uteri) and serum (n = 102) samples from 102 gilts were included. PCV-2 DNA was detected by using polymerase chain reactions. The localisation of PCV-2 antigen was determined by immunohistochemistry, and PCV-2 antibody was evaluated by ELISA. PCV-2 DNA was detected in 30.0% (21/70) of the ovaries and in 45.1% (46/102) of the uteri. Age did not influence the frequency of PCV-2 DNA detection in these reproductive organs of gilts (P > 0.05). The prevalence of PCV-2 DNA-positive uterine tissue in gilts culled due to non-reproductive problems (20.0%) was lower than gilts culled due to abortion (85.0%), abnormal vaginal discharge (47.5%) and anoestrus (53.5%) (P < 0.05). The prevalence of PCV-2 DNA-positive uterine tissue in the gilts with high antibody titres (23.0%) was lower than in gilts with low antibody titres (57.6%) and seronegative gilts (64.5%) (P < 0.05). PCV-2 immunostaining was detected in the endometrial cells, lymphocytes and macrophages of the uteri and in oocytes and granulosa cells of the ovaries. In conclusion, the detection of PCV-2 in the reproductive organs reveals an important potential impact of this virus on the reproductive apparatus in gilts.

Determination of GABAAα1 and GABAB1 receptor subunits expression in tissues of gilts during the late gestation

GABA(Aα1) and GABA(B1) receptor subunits are responsible for most behavioral, physiological and pharmacological effects of GABA receptors. We investigated the expression of GABA(Aα1) and GABA(B1) receptor subunits in different tissues of gilts during late pregnancy in hot summer. The mRNA abundance of GABA(Aα1) receptor subunit in different tissues of gilts at d 90 and d 110 of gestation was as follows: d 90: brain>lung>liver>ovary>spleen>kidney>heart; d 110: brain>lung>spleen>liver>ovary>kidney>heart. And, the mRNA abundance of GABA(B1) receptor subunit was as follows: d 90: spleen>lung>brain>kidney>ovary>liver>heart; d 110: spleen>lung>kidney>brain>ovary>liver>heart. The results in this trial indicated that the GABA(Aα1) receptor subunit was abundantly expressed in brain, while GABA(B1) receptor subunit was abundant in spleen and lung of gilts during late gestation. There were no gestation stage-dependent effects on GABA(Aα1) and GABA(B1) receptor subunits expression in all tissues.

Prevalence of porcine reproductive and respiratory syndrome virus (PRRSV) antigen-positive uterine tissues in gilts culled due to reproductive disturbance in Thailand

The objective of the present study was to determine the prevalence of porcine reproductive and respiratory syndrome virus (PRRSV) antigen-positive uterine tissue in gilts culled due to reproductive disturbance in relation to age at culling, reasons for culling, herds, and PRRSV vaccination. Uterine tissues of 100 gilts from six swine herds in Thailand were collected. The immunohistochemistry was performed to detect the PRRSV antigen using a polymer-based non-avidin-biotin technique. PRRSV was detected in the cytoplasm of the macrophages in the subepithelial connective tissue layers of the endometrium in 33.0% of the culled gilts. The detection of PRRSV antigen varied among the herds from 14.3% to 80.0% (P = 0.018). The detection of PRRSV in the uterine tissues at different ages was not statistically different (29.6%, 39.4%, and 40.9% in gilts culled at 6-8, 9-10, and 11-16 months of age, respectively, P = 0.698), similar to the reasons for culling (P = 0.929). PRRSV antigen was found in 24.5% of the gilts vaccinated against the EU-strain-modified-live PRRSV vaccine and in 23.1% of the gilts vaccinated against the US-strain-modified-live PRRSV (P = 0.941). The level of antibody titers against PRRSV had no impact on PRRSV antigen detection in the uterine tissues. Similarly, the detection of PRRSV antigen did not differ between the virgin gilts (35.4%) and the gilts mated before culling (30.8%) (P = 0.622). It can be concluded that PRRSV remains in the uterine tissue of the infected gilts for several months even though vaccinations and acclimatization have been carried out.

Growth characteristics, blood metabolites, and insulin-like growth factor system components in maternal tissues of gilts fed L-carnitine through day seventy of gestation1,2

A total of 59 gilts (BW = 137.7 kg) from 3 breeding groups were used to assess the effects of feeding l-carnitine during gestation on gilt growth characteristics, blood metabolites, and uterine and chorioallantoic expression of IGF axis components at d 40, 55, and 70 of gestation. Experimental treatments were arranged in a 2 x 3 factorial, with main effects of added l-carnitine (0 or 50 ppm) and day after initial breeding (d 40, 55, or 70 of gestation). All gilts received a constant feed allowance of 1.75 kg/d and a top-dress containing 0 or 50 ppm of l-carnitine beginning on the first day of breeding through the assigned day of gestation. No dietary treatment differences were observed for gilt BW, backfat, or estimated protein or fat mass at any day of gestation. No differences were observed in circulating total and free carnitine at breeding, but concentrations increased (P < 0.01) as day of gestation increased for gilts fed diets containing l-carnitine compared with those fed the control diet. Maternal IGF-I concentration decreased (P < 0.01) from d 0 to 70 for all gilts, with no differences between treatments. Insulin-like growth factor binding protein-3 mRNA (P = 0.05) and IGFBP-5 mRNA (P = 0.01) increased in the endometrium of gilts supplemented with l-carnitine. These data demonstrate that l-carnitine supplementation and day of gestation alter the expression of the IGF axis by changing the expression of IGFBP at the fetal-maternal interface in swine. These changes in the IGF axis at the fetal maternal interface may aid in determining the reasons for the effects of l-carnitine on reproductive traits.

Effect of dietary beta-carotene on the accumulation of beta-carotene and vitamin A in plasma and tissues of gilts.

The absorption of beta-carotene in pigs is limited. Nevertheless beta-carotene might positively affect reproduction. In this study the absorption and tissue distribution of beta-carotene as well as its function as precursor of vitamin A was investigated in gilts that were fed according to one of three dietary treatments: VA (4000 IU vitamin A), VA + VA (4000 IU + 8300 IU) and VA + BC (4000 IU + 100 mg beta-carotene per kg diet) for 14 weeks. Only in the VA + BC group was beta-carotene detected in plasma (1-8 ng x mL(-1)), liver, adrenals and corpora lutea, indicating that pigs absorb intact beta-carotene at low rates. Liver levels of vitamin A were higher (P < 0.01) at comparable levels in the VA + VA and VA + BC group than in the VA group, indicating a conversion rate of beta-carotene to vitamin A of 40 to 1 on the basis of weight for beta-carotene at this level (100 mg x kg(-1)) in the diet. Higher levels of vitamin A in the uterus of the VA + BC group (P < 0.01) as well as the accumulation of beta-carotene in adrenals and corpora lutea might reflect some influence of beta-carotene on local vitamin A metabolism which might be of importance for reproductive performance in gilts.

Progesterone receptor in the mammary tissue of pregnant and lactating gilts and the effect of tamoxifen treatment during late gestation

An isotope exchange assay using [3H]progesterone was used to examine progesterone receptor moieties in cytosolic extracts obtained from mammary tissue of gilts over the course of pregnancy and lactation, and during treatment of pregnant gilts with tamoxifen. Scatchard analysis was used to determine the concentrations and dissociation constants of progesterone receptors. The concentration of progesterone receptor was high at the onset of pregnancy (1394 fmol/mg DNA), fell to a nadir at 45 days (36 fmol/mg DNA), increased to a second maximum at 75 days (1232 fmol/mg DNA) and declined thereafter till parturition: the dissociation constant (Kd) of progesterone for its receptor remained stable during pregnancy with a mean Kd of 0.78 nmol/l. Progesterone receptors were not identifiable at day 21 of lactation. Treatment of pregnant gilts with tamoxifen (100 mg or 1.0 g/gilt per day orally identical to 0.70 or 7.0 mg/kg per day) did not affect the development of mammary structures or the ability to lactate at parturition; however, mammary progesterone receptor content in tamoxifen-treated animals tended to be lower than the controls at day 90 of pregnancy (15.7 +/- 1.56 vs 27.0 +/- 3.75 fmol/mg protein respectively). The results show that a temporal relationship exists between oestrogen concentrations in the circulation of pregnant gilts with progesterone receptor content in mammary tissue.

Quantification of receptors for estradiol-17 beta and progesterone in the pituitary and hypothalamus of prepubertal gilts induced to ovulate with pregnant mare's serum and human chorionic gonadotropin.

Nuclear and cytoplasmic exchange assays were developed and validated to quantify receptors for estradiol-17 beta (E217 beta) and progesterone (P4) in hypothalamic and pituitary tissues of gilts before, during, and after treatment with pregnant mare's serum (PMS) and human chorionic gonadotropin (hCG). Prepubertal gilts, 5 months old, were assigned randomly to four treatments. One group of gilts received 500 IU PMS (Day 0) and were sacrificed 2 days later (2 days post-PMS); another group received 500 IU PMS on Days 0 and 2, and were sacrificed 4 days from the initial injection (4 days post-PMS). A third group of gilts received PMS (500 IU) on Days 0 and 2, 1000 IU hCG on Day 4, and were sacrificed 5 days after hCG (5 days post-hCG). Controls were given saline on Days 0, 2 and 4 and sacrificed on Day 6. In pituitary tissues, there were no significant changes in numbers of cytoplasmic E2 17 beta receptors, cytoplasmic P4 receptors, nuclear P4 receptors or nuclear E2 17 beta receptors among the control, 2 days post-PMS, 4 days post-PMS or 5 days post-hCG treatment groups. In hypothalamic tissues, no differences in cytoplasmic E2 17 beta receptors, cytoplasmic P4 receptors or nuclear P4 receptors were found among any of the treatments. Nuclear receptors for E2 17 beta in hypothalamic tissues were greater, however, in gilts 2 days post-PMS (P less than 0.05) than in controls or 5 days post-hCG gilts, but they were not different from gilts 4 days post-PMS. Follicular development and serum concentrations of E2 17 beta followed the expected patterns after PMS; only ovaries from hCG-treated pigs contained corpora lutea. Because the PMS-hCG regimen simulated the onset of puberty, it seems that gilts attain puberty without a significant change in the number of receptors for E2 17 beta and P4 in the pituitary or hypothalamus.