Abstract: This research aimed to explore the effect of sturgeon head soup, made by high-pressure liquefaction after cooking, in promoting milk secretion in rats with postpartum hypogalactia. Lactating Wistar rats were randomly assigned into blank, bromocriptine-induced hypogalactia, positive control (whey + seabass power), and experimental (sturgeon head soup) groups (n = 6). After 14 days of oral administration, the changes in body mass and milk secretion were investigated. Mammary gland morphology, related hormone levels and protein expression were measured by hematoxylin eosin (HE) staining, immunohistochemistry, enzyme linked immunosorbent assay (ELISA) and real-time fluorescence quantitative polymerase chain reaction (qPCR). The results showed that for the experimental group, an increase in the secretion of proteins that showed a brownish yellow in immunohistochemical analysis was observed in the mammary glandular ducts and acini along with a decrease in the number of adipose connective tissue between the mammary glandular lobules compared with the model group. Milk productivity, mammary gland to body mass ratio, and percent body mass gain of the whole litter of suckling rats were significantly increased in the experimental group (P < 0.05). The levels of prolactin (PRL), prolactin receptor (PRLR), β-casein (β-CN), α-lactalbumin (α-LA), lactose synthase (LS) and fatty acid synthase (FAS) were significantly elevated in the maternal serum and mammary tissue. The mRNA expression of the genes regulating the synthesis of β-CN and FAS in the mammary gland was significantly up-regulated compared with the model group. These results suggest that sturgeon head soup can promote milk secretion in rats with postpartum hypogalactia, and the underlying mechanism may be related to increasing the contents of PRL and PRLR and promoting the expression of β-CN, α-LA and FAS.

Key words: sturgeon head soup; postpartum hypogalactia; prolactin; β-casein; α-lactalbumin; fatty acid synthase