Progesterone (P4) plays a key role in pregnancy establishment and maintenance; during early pregnancy, P4 stimulates the production and release of uterine secretions necessary for conceptus growth prior to implantation; therefore, exogenous P4 supplementation may improve embryo development. This study evaluated the effects of supplementation during early pregnancy with long-acting injectable progesterone or altrenogest on embryonic characteristics of sows and gilts. Thus, a total of 32 sows and 16 gilts were used. On day 6 of pregnancy sows and gilts were allocated to one of the following groups: non-supplemented; supplemented with 20 mg of altrenogest, orally, from days 6 to 12 of pregnancy; supplemented with 2.15 mg/kg of long-acting injectable progesterone on day 6 of pregnancy. Animals were killed on day 28 of pregnancy, and ovulation rate, embryo survival, embryo weight, crown-to-rump length, uterine glandular epithelium and endometrial vascularization were assessed. Treatments had no effect on pregnancy rate, embryo survival or endometrial vascular density (P > 0.05). Non-supplemented gilts presented larger and heavier embryos compared to gilts from supplemented groups (P < 0.05). Sows in the altrenogest group presented larger and heavier embryos compared to non-supplemented sows and sows supplemented with long-acting injectable progesterone. In conclusion, supplementation of sows and gilts with progestagen from day 6 of pregnancy can be used as a means to improve embryo survival without deleterious effects.

The study aimed to evaluate the supplementation of gilts with cow’s milk naturally enriched with n-3 and n-6 polyunsaturated fatty acids (PUFA) on reproductive outcomes, and the serum biochemical and FA profile of swine females and their offspring. During 316 days, 30 gilts were distributed into three groups: (1) Control, fed a basal diet + milk from cows without oil; (2) n-3, fed a basal diet + milk from cows fed a diet enriched with linseed oil; (3) n-6, fed a basal diet + milk from cows fed a diet enriched with soybean oil. The gilts receiving the diets containing PUFA had higher serum urea and very-low-density lipoprotein levels and lower serum total protein and low-density lipoprotein levels compared to the Control group. Females supplemented with n-3 presented higher serum palmitic acid and γ-linolenic acid levels than those fed n-6. Piglets from the Control group were heavier at birth than those from females supplemented with enriched milk. The piglets from females receiving enriched milk had 140 g higher body weight from 1 to 21 days old compared to the Control group, and greater average daily weight gain from 7 to 14 days old. The serum eicosapentaenoic acid level of piglets fed n-3 was 69% higher than those fed n-6, which reduced the AA/EPA ratio. Gilts supplemented with PUFA-enriched cow’s milk showed changes in their serum palmitic and γ-linolenic acid levels, in addition to improved performance, EPA concentration and consequently reduced AA/EPA ratio in their piglets, demonstrating beneficial results for their progeny.

This study evaluated the effects of supplying altrenogest from day 6-12 of pregnancy on the endometrial glandular epithelium, corpora lutea (CL) morphology, and endometrial and CL gene expression. A total of 12 crossbred females (Landrace × Large White) were used. The females were assigned to 4 treatments according to a random design with a 2 × 2 factorial arrangement, with two categories (sow or gilt) and two treatments (non-treated and treated with altrenogest). On day 6 of pregnancy, animals were allocated to one of the following groups: non-treated (NT, n = 6; 3 sows and 3 gilts), and (T, n = 6; 3 sows and 3 gilts) treated daily with 20 mg of altrenogest, from day 6-12 of pregnancy. All animals were euthanized on day 13 of pregnancy. All CLs were individually weighed, and their volume were determined. The endometrial glandular density (GD), mean glandular area (MGA), and vascular density (VD) were determined by histomorphometric and immunohistochemical analyses. Endometrium samples were collected and analyzed by qRT-PCR to evaluate the abundance of transcripts for VEGF and IGF-I. Females in the T group had higher MGA (P < 0.05) compared to the NT group. There was no effect of treatment on GD or VD for both experimental groups. Sows in the T group had augmented expression of IGF-I (P < 0.05). Progestagen had no detrimental effect on CL morphology. In conclusion, altrenogest improves the uterine environment during the peri-implantation period in pigs without compromising corpora lutea development.

The use of altrenogest (ALT) supplementation for oestrous synchronization improves subsequent reproductive performance of gilts and sows. However, the causes of this improvement in reproductive performance after ALT treatment are not fully/clearly understood. The objective of this study was to evaluate the effects of ALT supplementation for oestrous synchronization in gilts on the endometrial glands and embryonic development characteristics at 28 days of pregnancy. Pregnant gilts were divided into two experimental treatments: Control (did not receive ALT; n = 9 gilts) and ALT (ALT feeding at 20 mg/day for 18 days; n = 9 gilts). At 28 days of pregnancy, six gilts from each treatment were slaughtered, and reproductive tracts were immediately evaluated. There was no statistical difference (P > 0.05) between treatments regarding ovulation rate, number of embryos, number of vital embryos and number of non-vital embryos. Embryo weight, length and embryonic vesicle weight were lower in ALT treatment compared with Control (P < 0.01), and it was lower in the cervical uterine region compared with apex uterine region, respectively (P < 0.05). Higher values of gland duct area, gland duct perimeter, percentage of the glandular area and total endometrial area were observed in ALT treatment compared with Control (P < 0.05). The use of ALT during 18 days for oestrous synchronization in gilts increased the gland duct area, perimeter and total endometrial area but did not increase the embryo number and embryo size at day 28 of pregnancy.

This study aimed to compare different selenium (Se) sources in the diet on boar's semen quality and fertility. For this, 28 boars aged 8 to 28 months were fed with the following dietary treatments for 95 days: 0.3 mg Se/kg as sodium selenite (SS, n = 14) and 0.3 mg Se/kg as hydroxy-selenomethionine (OH-SeMet, n = 14). During this period, two experiments were carried out. In experiment 1, the semen of all boars was evaluated every 2 weeks. Raw semen was initially evaluated for the processing of seminal doses, which were stored at 17 °C for 72 h, followed by sperm quality assessments. Furthermore, Se concentration and glutathione peroxidase (GPx) activity were measured in the seminal plasma. In experiment 2, 728 females were inseminated weekly with seminal doses from boars of the different experimental groups to further assess in vivo fertility and litter characteristics. Results demonstrated that boars fed OH-SeMet had more Se in their seminal plasma (p &lt; 0.05), showing the greater bioavailability of the organic source in the male reproductive system. Moreover, boars fed OH-SeMet tended (p &lt; 0.10) towards a higher total sperm count in the ejaculate (66.60 vs. 56.57 × 10 9 sperm), and the number of seminal doses (22.11 vs. 18.86; 3 × 10 9 sperm/dose) when compared to those fed SS. No effect of the dietary treatments was observed on GPx activity in seminal plasma (p &gt; 0.05), as well as on raw and stored semen quality (p &gt; 0.05). Under in vivo conditions, seminal doses from boars fed OH-SeMet tended (p &lt; 0.10) towards a higher pregnancy rate at weeks 3, 5, and 8, and also resulted in a higher (p &lt; 0.05) percentage of pregnant females in the overall period (99.30 vs. 97.00). In conclusion, the replacement of SS with OH-SeMet in boars' diet can improve sperm production and results in better reproductive performance for them, bringing greater productivity and profitability to artificial insemination centers and commercial pig farms.