Parity affects mammary development in late-pregnant swine.
| Autor: | Farmer C; Agriculture and Agri-Food Canada, Sherbrooke Research and Development Centre, 2000 College, Sherbrooke, QC, CanadaJ1M 0C8., Johannsen JC; Department of Animal and Veterinary Sciences, Aarhus University, DK-8830 Tjele, Denmark., Gillies C; Department of Animal Biosciences, University of Guelph, Guelph, ON, CanadaN1G 2W1., Huber LA; Department of Animal Biosciences, University of Guelph, Guelph, ON, CanadaN1G 2W1., Hovey RC; Department of Animal Science, University of California, Davis, CA 95616, USA. |
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| Jazyk: | angličtina |
| Zdroj: | Translational animal science [Transl Anim Sci] 2024 Mar 23; Vol. 8, pp. txae037. Date of Electronic Publication: 2024 Mar 23 (Print Publication: 2024). |
| DOI: | 10.1093/tas/txae037 |
| Abstrakt: | The goal of this project was to determine whether various measures of mammary development differed between gilts and multiparous sows at the end of gestation. During gestation, Yorkshire × Landrace gilts ( n = 19) and sows (second and third gestations, n = 17) were fed one daily meal of a conventional corn-based diet, where the amount fed was based on body weight (BW) and backfat thickness (BF) at mating. On day 110 ± 1 of gestation, a jugular blood sample was obtained from all gilts and sows to measure insulin-like growth factor-1 (IGF-1), glucose, free fatty acids, and urea. On that same day, BW and BF were measured and animals were euthanized. Mammary glands from one side of the udder were dissected for compositional analyses. The fifth gland of the contralateral row of mammary glands was sampled for histology and immunohistochemical localization of Ki67. There was less total parenchyma (1,437.4 vs. 2,004.7 ± 127.1 g; P < 0.001) and total extraparenchymal tissue (1,691.0 vs. 2,407.0 ± 125.3 g; P < 0.001) in mammary glands of gilts compared to those from sows. When these values were expressed per kg BW (226.0 and 284.0 ± 2.7 kg for gilts and sows, respectively), parenchymal mass did not differ ( P > 0.10), while extraparenchymal tissue weight tended to be less in gilts than sows ( P = 0.07). All components within the parenchyma differed by parity ( P < 0.001). Specifically, parenchymal tissue from gilts contained a greater proportion of fat and dry matter (DM), a lower proportion of protein, and lower concentrations of DNA (6.59 vs. 9.35 ± 0.53 mg/g DM) and RNA (7.76 vs. 12.33 ± 0.70 mg/g DM) than that from sows. On the other hand, the circumference of alveolar lumens was greater in gilts than sows ( P < 0.001), while the percentage of epithelial cells that were positive for Ki67, a marker of cell proliferation, was greater in sows than gilts ( P < 0.05). Circulating concentrations of IGF-1 were greater in gilts than in multiparous sows (45.0 vs. 27.3 ± 2.8 ng/mL, P < 0.001). None of the other blood variables were changed by parity. Results show a marked effect of parity on mammary gland development in swine. At the end of gestation, the mammary glands of gilts had less parenchyma with lower epithelial proliferation than glands from multiparous sows. These differences could alter the response of mammary tissue to various nutritional or endocrine signals. This information is crucial for the development of management strategies designed to maximize sow milk yield. Competing Interests: The authors declare no conflict of interest. (© His Majesty the King in Right of Canada, as represented by the Minister of Agriculture and Agri-Food Canada, 2024.) |
| Databáze: | MEDLINE |
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