Effect of altrenogest treatment before weaning on reproductive performance and production efficiency in primiparous and multiparous sows.

BACKGROUND: Most sows will experience negative energy balance during lactation resulting in impaired follicular development. This study aimed to treat 28-day lactating sows with altrenogest (ALT) to suppress follicle enlargement during lactation, and to assess the estrus and reproductive performance post-weaning. METHODS: In this study, we conducted two trials. In trial 1, we monitored the follicular development of lactating sows including 10 primiparous sows and 10 multiparous sows during the whole lactation to confirm the ALT administration time. In trial 2, a total of 42 primiparous and 111 multiparous sows were allocated to three treatments: Ctrl (control group, n = 51): no treatment; TAI (timed artificial insemination group, n = 51): sows were injected with equine chorionic gonadotropin (eCG) after weaning 24 h and gonadotropin-releasing hormone (GnRH) when they expressed estrus; and AT-TAI (ALT treatment-timed artificial insemination group, n = 51): base on the process of TAI group, the sows were fed with 20 mg ALT per day before weaning 10 days. All sows were artificially inseminated twice at 12 h and 36 h after estrus. The follicle size changes and serum hormone levels were explored in this process. RESULTS: Although the follicle size of multiparous sows was larger than primiparous sows during the whole lactation (P < 0.05), similar change trends of follicle size were observed in primiparous and multiparous sows. Meanwhile, the FSH, LH and E2 levels of multiparous sows were higher than primiparous sows. The ALT treatment significantly inhibits the increase in follicle size (P < 0.05) and reduces the serum levels of FSH, LH and E2 (P > 0.05). Additionally, ALT treatment increases estrus concentration and the preovulatory follicle size (P < 0.05), meanwhile, it delays the weaning-to-estrus interval (WEI, P < 0.001). However, the estrus rate, pregnancy rate, total pigs born and born alive did not differ between treatments (P > 0.05). CONCLUSIONS: There were significant differences in the size of follicles in the lactation between primiparous and multiparous sows. ALT treatment during the last ten days of lactation concentrated estrus expression leading to higher work efficiency of breeder in batch production, however, with no improvement in reproductive performance.

Effect of cholesterol-loaded cyclodextrin treatment on boar sperm cryopreservation.

Objective: This study investigated the efficacy of different concentrations of Cholesterol-loaded cyclodextrin (CLC) on cryopreservation in boar sperm quality. Methods: In this study, we treated boar sperm with different concentrations of CLC before freezing and analyzed the sperm cholesterol concentration, plasma membrane, acrosome integrity rate and total motility rate before and after freeze-thawing. We also investigated the levels of reactive oxygen species (ROS), malondialdehyde (MDA), ATP, and structural- and oxidative-damage related proteins in all groups after thawing. Results: The results revealed that the cholesterol concentration of the CLC-treated groups was higher than that of the control group, both before freezing and after thawing (p < 0.05). The plasma membrane integrity rate, acrosome integrity rate, and total motility rate of sperm were also enhanced after thawing in the CLC-treated group (all p < 0.05). Moreover, ROS and MDA production and ATP loss were reduced in CLC-treated sperm during freezing and thawing (p < 0.05). Finally, CLC pretreatment partially prevented the consumption of various proteins involved in metabolism including CAPZB, HSP90AA1 and PGAM2 (p < 0.05). Conclusion: CLC treatment increased cholesterol concentration and decreased structural injury and oxidative damage during boar sperm freezing and thawing, improving the efficacy of sperm cryopreservation in boar.

The Antioxidant Salidroside Ameliorates the Quality of Postovulatory Aged Oocyte and Embryo Development in Mice.

Postovulatory aging is known to impair the oocyte quality and embryo development due to oxidative stress in many different animal models, which reduces the success rate or pregnancy rate in human assisted reproductive technology (ART) and livestock timed artificial insemination (TAI), respectively. Salidroside (SAL), a phenylpropanoid glycoside, has been shown to exert antioxidant and antitumor effects. This study aimed to investigate whether SAL supplementation could delay the postovulatory oocyte aging process by alleviating oxidative stress. Here, we show that SAL supplementation decreases the malformation rate and recovers mitochondrial dysfunction including mitochondrial distribution, mitochondrial membrane potential (ΔΨ) and ATP content in aged oocytes. In addition, SAL treatment alleviates postovulatory aging-caused oxidative stress such as higher reactive oxygen species (ROS) level, lower glutathione (GSH) content and a reduced expression of antioxidant-related genes. Moreover, the cytoplasmic calcium ([Ca2+]c) and mitochondrial calcium ([Ca2+]mt) of SAL-treated oocytes return to normal levels. Notably, SAL suppresses the aging-induced DNA damage, early apoptosis and improves spindle assembly in aged oocytes, ultimately elevating the embryo developmental rates and embryo quality. Finally, the RNA-seq and confirmatory experience showed that SAL promotes protective autophagy in aged oocytes by activating the MAPK pathway. Taken together, our research suggests that supplementing SAL is an effective and feasible method for preventing postovulatory aging and preserving the oocyte quality, which potentially contributes to improving the successful rate of ART or TAI.

Association of Metabolic and Endocrine Disorders with Bovine Ovarian Follicular Cysts.

After estrus, when mature follicles fail to ovulate, they may further develop to form follicular cysts, affecting the normal function of ovaries, reducing the reproductive efficiency of dairy cows and causing economic losses to cattle farms. However, the key points of ovarian follicular cysts pathogenesis remain largely unclear. The purpose of the current research was to analyze the formation mechanism of ovarian follicular cysts from hormone and gene expression profiles. The concentrations of progesterone (P4), estradiol (E2), insulin, insulin-like growth factor 1 (IGF1), leptin, adrenocorticotropic hormone (ACTH) and ghrelin in follicle fluid from bovine follicular cysts and normal follicles were examined using enzyme-linked immunosorbent assay (ELISA) or 125I-labeled radioimmunoassay (RIA); the corresponding receptors' expression of theca interna cells was tested via quantitative reverse transcription polymerase chain reaction (RT-qPCR), and the mRNA expression profiling was analyzed via RNA sequencing (RNA-seq). The results showed that the follicular cysts were characterized by significant lower E2, insulin, IGF1 and leptin levels but elevated ACTH and ghrelin levels compared with normal follicles (p < 0.05). The mRNA expressions of corresponding receptors, PGR, ESR1, ESR2, IGF1R, LEPR, IGFBP6 and GHSR, were similarly altered significantly (p < 0.05). RNA-seq identified 2514 differential expressed genes between normal follicles and follicular cysts. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis linked the ovarian steroidogenesis pathway, especially the STAR, 3ß-HSD, CYP11A1 and CYP17A1 genes, to the formation of follicular cysts (p < 0.01). These results indicated that hormone metabolic disorders and abnormal expression levels of hormone synthesis pathway genes are associated with the formation of bovine ovarian follicular cysts.

N-Carbamylglutamate Improves Reproductive Performance and Alters Fecal Microbiota and Serum Metabolites of Primiparous Sows during Gestation after Fixed-Time Artificial Insemination.

N-carbamylglutamate (NCG) supplementation during gestation improves reproductive performance in sows after conventional artificial insemination. However, whether NCG can improve reproductive performance and change fecal microbiota and serum metabolite levels during pregnancy in sows after fixed-time artificial insemination (FTAI) remains unclear. Two hundred multiparous sows were assigned a diet from mating until farrowing: control (corn−soybean meal) or NCG supplementation (0.05% NCG). At days 30, 70, and 110 of gestation and after farrowing, maternal microbial diversity and serum metabolites were studied. Supplementation of NCG increased the number of piglets born alive and the litter weight (all p < 0.05) and altered the fetal microbial community during gestation. Some genera were particularly abundant at different time points during gestation and after farrowing, but none were commonly abundant across all four time points. Metabolic analysis revealed that NCG supplementation significantly increased the serum concentrations of NCG, ferulic acid, cinnamoylglycine, 3-phenyllactic acid, and gamma-glutamylglutamic acid in the NCG group compared with levels in the control group. Our results reveal that NCG supplementation during gestation improves reproductive performance in sows after FTAI, exerting both direct (increased serum NCG levels) and indirect effects (altered intestinal microbiome and serum metabolites) on sow reproduction and, ultimately, improving placental and fetal development.