Iron is an important trace element that affects the growth and development of animals and regulates oxygen transport, hematopoiesis, and hypoxia adaptations. Wujin pig has unique hypoxic adaptability and iron homeostasis; however, the specific regulatory mechanisms have rarely been reported. This study randomly divided 18 healthy Wujin piglets into three groups: the control group, supplemented with 100 mg/kg iron (as iron glycinate); the low-iron group, no iron supplementation; and the high-iron group, supplemented with 200 mg/kg iron (as iron glycinate). The pre-feeding period was 5 days, and the formal period was 30 days. Serum was collected from empty stomachs before slaughter and at slaughter to detect changes in the serum iron metabolism parameters. Gene expression in the liver was analyzed via transcriptome analysis to determine the effects of low- and high-iron diets on transcriptome levels. Correlation analysis was performed for apparent serum parameters, and transcriptome sequencing was performed using weighted gene co-expression network analysis to reveal the key pathways underlying hypoxia regulation and iron metabolism. The main results are as follows. (1) Except for the hypoxia-inducible factor 1 (HIF-1) content (between the low- and high-iron groups), significant differences were not observed among the serum iron metabolic parameters. The serum HIF-1 content of the low-iron group was significantly higher than that of the high-iron group (p < 0.05). (2) Sequencing analysis of the liver transcriptome revealed 155 differentially expressed genes (DEGs) between the low-iron and control groups, 229 DEGs between the high-iron and control groups, and 279 DEGs between the low- and high-iron groups. Bioinformatics analysis showed that the HIF-1 and transforming growth factor-beta (TGF-β) signaling pathways were the key pathways for hypoxia regulation and iron metabolism. Four genes were selected for qPCR validation, and the results were consistent with the transcriptome sequencing data. In summary, the serum iron metabolism parameter results showed that under the influence of low- and high-iron diets, Wujin piglets maintain a steady state of physiological and biochemical indices via complex metabolic regulation of the body, which reflects their stress resistance and adaptability. The transcriptome results revealed the effects of low-iron and high-iron diets on the gene expression level in the liver and showed that the HIF-1 and TGF-β signaling pathways were key for regulating hypoxia adaptability and iron metabolism homeostasis under low-iron and high-iron diets. Moreover, HIF-1α and HEPC were the key genes. The findings provide a theoretical foundation for exploring the regulatory pathways and characteristics of iron metabolism in Wujin pigs.

Iron deficiency in sows has been demonstrated to have a detrimental effect on porcine fetal growth and development, as well as on the reproductive performance of sows. The placental barrier of sows restricts the transportation of inorganic iron to the fetus, resulting in iron deficiency anemia in neonatal piglets and consequently leading to slow growth. The purpose of this study is to explore the effect of heme Fe on iron metabolism in pregnant sows. Ninety-six multiparous Landrace × Yorkshire (LY) sows (weight 235 ± 15kg) with similar litter size and feeding management were randomly divided into four treatment groups: control group (supplemented with 400 mg/kg), iron deficiency group (with no added FeSO₄), heme Fe group (supplemented with 140 mg/kg), and glycine Fe group (supplemented with 470 mg/kg). Iron supplementation lasted from the second trimester (day 30) to day 114 before delivery. In this study, the production performance of sows, the iron content in sow placentas, and in the livers, spleens, placenta and colostrum of newborn piglets, as well as the hemoglobin(HGB) level, the iron regulation parameters in the serum of newborn piglets and the iron regulation genes in the livers and placentas were measured. The results showed that: (1) The number of live births and the average birth weight of piglets in the heme Fe group were 14.8% and 6.33% higher than those in the control group, respectively(P < 0.01). Compared with FeSO₄ and glycine Fe, heme Fe improved the production performance of sows. (2) In the heme Fe group, the iron content in colostrum was significantly higher than in the control group (1.27-fold) and glycine Fe group (0.45-fold), while the iron content in the livers of newborn piglets increased by 30.38% and 14.61% compared to the control and glycine Fe groups, respectively (P < 0.01). These results suggest that heme Fe significantly facilitates iron transport in sows, particularly enhancing its deposition in colostrum and neonatal livers. This effect may be attributed to the upregulated expression of heme oxygenase 1(HO-1) gene in the placenta, which enhances the uptake and transport of heme Fe, thereby increasing fetal iron acquisition.(3) In the liver and placentas of sows in the deficiency group, the expression of hepcidin was decreased, while the expressions of transferrin receptor 1 (tfr1), feline leukemia virus subgroup C receptor 1(Flvcr1) and transferrin were increased (P < 0.01). In addition, the gene expression level of HO-1 in the heme Fe group of liver was significantly higher compared to that in the control group (1.85-fold), the iron deficiency group (2.99-fold), and the iron glycinate group (1.67-fold). In conclusion, maternal heme Fe supplements have a significant impact on iron storage in neonatal piglets and are helpful for preventing iron deficiency in newborn piglets.

Introduction: This study investigated whether glycyrrhetinic acid (GA) can alleviate the reproductive toxicity of Zearalenone (ZEN) in replacement gilts.Methods: Eighty Landrace × Yorkshire gilts were randomly assigned to four dietary groups: control (basal diet), ZEN (1 mg/kg), GA (400 mg/kg), and ZEN + GA (1 mg/kg ZEN + 400 mg/kg GA).Results: The onset of estrus advanced significantly in all treatment groups, with the GA and ZEN + GA groups showing the most pronounced changes. Puberty onset occurred earlier in the ZEN group and was further advanced by GA supplementation. ZEN exposure impaired uterine and ovarian development, while GA improved organ development and mitigated the abnormalities in the ZEN + GA group. Hormonal analysis revealed that ZEN reduced estradiol (E2) and luteinizing hormone (LH), whereas GA elevated all measured hormones. The ZEN + GA group showed a partial recovery in hormone levels, excluding E2. Histological examination of liver tissue in the ZEN group revealed focal hepatocellular necrosis and lymphocyte infiltration, which GA notably attenuated. ZEN upregulated 3α/3β/17β-hydroxysteroid dehydrogenase (HSD) gene expression in the liver and duodenum, while GA co-administration downregulated most HSD genes except hepatic 3α-HSD.Discussion and conclusion: These findings suggest that GA can alleviate ZEN-induced reproductive toxicity via modulation of endocrine and hepatic metabolic pathways.

Impact of different dietary fibre levels on the roughage resistance of the Dahe black pig | Ye Wang, Chaoying Liu, Jinjin Zhu, Enzhong Li, Mingcheng Wang, Zhichao Shen, Xinfeng Yang, Guojin Lv, Rongfu Guo | Agricultural Journals