Impact of dietary fat levels and fatty acid composition on milk fat synthesis in sows at peak lactation

Maternal consumption of glycerol monolaurate optimizes milk fatty acid profile and enhances piglet gut health in association with G protein-coupled receptor 84 (GPR84) activation

This study evaluated the effect of maternal glycerol monolaurate (GML) supplementation during late gestation and lactation on sow reproductive performance, transfer of immunity and redox status, milk fat and fatty acid profile, and fecal microbiota. Eighty multiparous sows (Landrace × Large white) were randomly allocated to two treatment groups (with or without 1000 mg/kg GML) with 40 replicates per treatment. The feeding experiment lasted from d 85 of gestation (G85) to d 23 of lactation (L23). The samples were collected on d 1 (L1) and 21 (L21) of lactation. Our results showed that maternal GML supplementation significantly increased litter weight (P = 0.002), average daily gain of piglets (P = 0.048), and sow average daily feed intake (P = 0.032). Compared with CON group, the concentrations of lauric acid (C12:0; P = 0.022), C16:0 (P = 0.001), and total saturated fatty acids (P = 0.006) in colostrum as well as C12:0 in L21 milk (P = 0.001) were higher in GML group. Besides, the concentrations of immunoglobulin A (IgA) and IgG in colostrum as well as sow and piglet plasma, the total antioxidant capacity and superoxide dismutase activity in sow colostrum were also significantly higher in the GML group (P < 0.05). Microbiome results showed that GML addition increased fecal microbial alpha diversity as well as the relative abundances of short chain fatty acids producing bacteria Ruminococcaceae and Parabacteroides; and decreased the harmful Proteobacteria of sows (P < 0.05). The Spearman analysis showed that the microbial biomarkers Prevotellaceae, Ruminococcaceae, and Parabacteroides were positively correlated with IgA and IgG of sow plasma and milk (P < 0.05). Besides, maternal GML addition up-regulated the relative protein expressions of proliferating cell nuclear antigen, cyclin D1, G protein-coupled receptor 84 (GPR84) and phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway in the duodenum and jejunum of piglets. Collectively, current findings suggested that maternal GML supplementation enhanced piglet growth during lactation, which might be associated with improving milk fat and lauric acid contents, microbiota derived immunoglobulins transfer, and gut health through potential involvement of GPR84 and PI3K/Akt signaling pathway.

Alterations in Milk Biomolecular Profiles and Piglet Performances Due to Dietary Probiotic Bacillus licheniformis DSMZ 28710 Supplementation

The present study aimed to investigate the effects of probiotic Bacillus licheniformis DSMZ 28710 supplementation on sow performance, Preweaning piglet performance, and the biochemical profiles of colostrum and milk. Sixty-eight crossbred sows (Landrace× $\times $ Yorkshire) were allocated to either a standard lactation diet (Control; n = 35) or the Control diet supplemented with 10 g/sow/day of B. licheniformis DSMZ 28710 (Treatment; n = 33), from day 109 of gestation until day 21 of lactation. Sow and piglet performance, as well as the incidence of piglet diarrhea, were recorded. Moreover, the study investigated the changes in major chemical compositions, immunoglobulins, fatty acids, and non-volatile polar metabolites in colostrum, transient milk, and mature milk of sows. Supplementation of B. licheniformis increased piglet body weight on day 21 of lactation in old parity sows (p = 0.037). Moreover, the incidence of diarrhea was reduced in piglets suckled by sows supplemented with B. licheniformis DSMZ 28710, regardless of sow's parity or lactation stage (p < 0.05). Probiotic supplementation decreased fat content in transient milk (p = 0.026) and increased lactose content in mature milk (p = 0.011). Chemometric analysis revealed clear distinctions between the Control and Treatment group in the fatty acid profiles of colostrum, transient milk, and mature milk, while notable differences in non-volatile polar metabolite profiles were observed specifically in mature milk. In conclusion, supplementation with B. licheniformis DSMZ 28710 reduced the incidence of diarrhea in piglets, increased body weight of the piglets in old parity sows and altered the biomolecular profiles in colostrum, transit milk, and mature milk of the sows.

Valine metabolite, 3-hydroxyisobutyrate, promotes lipid metabolism and cell proliferation in porcine mammary gland epithelial cells

Improving mammary gland epithelial cells proliferation through nutrition is an important approach for enhancing sow milk production and piglet growth. An intermediate metabolite of valine, 3-hydroxyisobutyrate (3-HIB), regulates cellular lipid metabolism. In the present study, we investigated the effects of 3-HIB on porcine mammary gland epithelial cells proliferation and lipid metabolism. The addition of an appropriate concentration of 3-HIB significantly increased mammary gland epithelial cell proliferation and the expression of proteins associated with cell proliferation. Compared to the control group, the addition of 0.4-0.8 mM 3-HIB increased the expression levels of mTOR signaling pathway-related proteins and the cell cycle protein, Cyclin D1, while inhibiting the expression of the cell cycle arrest protein, P27. The addition of 0.8 mM 3-HIB increased the triglyceride and lipid droplet content in the cells. The addition of 3-HIB increased the expression of proteins related to de novo fatty acid synthesis and transport, resulting in a marked increase in most polyunsaturated fatty acids in the 3-HIB-added group. Compared to the control group, the addition of 0.8 mM 3-HIB increased the expression levels of the fatty acid oxidation-related proteins, ACSL and CAD, ultimately increasing cellular ATP synthesis. In summary, the addition of 0.8 mM 3-HIB to porcine mammary gland epithelial cells promotes cell proliferation by enhancing lipid metabolism and the expression of cell proliferation-related proteins.

Restricted vs. ad libitum feeding during sow gestation affects piglet performance, behavior, and fecal microbiota composition

This study investigated how the nutrition of gestating sows affects piglet performance, behavior, and fecal microbiota. Twenty-four sows were divided into 2 feeding groups: those on a restricted diet (once a day) and those fed ad libitum (as much as they wanted), with all receiving the same diet during lactation. The piglets were categorized based on their feeding groups; RG-RL: Piglets born and nursed by restricted-fed sows with restricted feeding, AG-AL: Piglets born and nursed by ad lib-fed sows, RG-AL: Piglets born by restricted-fed sows and nursed by ad lib-fed sows, and AG-RL: Piglets born by ad lib-fed sows and nursed by restricted-fed sows. Performance traits were analyzed using the model including treatment, switching piglets, and room effects. Piglet behavior was evaluated with a generalized linear mixed model (GLMM) using binomial distribution, testing interactions of treatment, switching, gender, and other factors while accounting for random effects related to room, pen, and sow. Results showed that ad lib-fed sows had higher feed intake (P < 0.001), weight gain (P = 0.04), and backfat gain (P = 0.01) compared to restricted-fed sows. They also had lower cortisol levels during gestation (P = 0.02) and lactation (P = 0.04). Restricted-fed sows displayed more air-chewing behavior (P = 0.002), while ad lib-fed sows were more active (P = 0.03) and engaged in eating (P < 0.001). Birth weights and the number of piglets were similar across groups. During lactation, backfat loss varied among piglet groups, with the highest loss in AG-RL (P < 0.01). Piglets from ad lib-fed sows performed better overall, regardless of nursing source. At weaning, piglet weights (P = 0.01) were highest in AG-AL, followed by RG-AL, RG-RL, and AG-RL (interaction effect P = 0.006). Switching piglets initially reduced their playtime but later increased it (P = 0.04). The novel object test indicated that gilts became more active, resembling boars. Additionally, gut microbiota composition varied among sow groups during gestation (P = 0.04) and lactation (P = 0.02), suggesting that maternal diet influences piglet gut health. Overall, these findings highlight the potential role of epigenetic mechanisms in shaping these traits.

Effects of Dietary Net Energy Concentration on Reproductive Performance, Immune Function, Milk Composition, and Gut Microbiota in Primiparous Lactating Sows

This study aimed to determine the optimal dietary net energy concentration for the reproductive performance, immune function, milk composition, and gut microbiota of primiparous sows during lactation. Forty primiparous lactating sows (Landrace × Yorkshire) with similar body backfat thicknesses were randomly allocated into five treatment groups and fed diets with different dietary net energy concentrations of 10.05 MJ/kg, 10.47 MJ/kg, 10.89 MJ/kg, 11.30 MJ/kg, and 11.72 MJ/kg. The results showed that there were no differences in the performance of piglets, while there was a decrease in the daily feed intake of sows (p = 0.079, linear) as dietary net energy concentration increased. With the increasing dietary net energy concentration, the plasma insulin levels of sows increased (p < 0.01, linear), the plasma glucose levels tended to increase (p = 0.074, linear), and the blood urea nitrogen levels tended to decrease (p = 0.063, linear). Moreover, the plasma total superoxide dismutase activity of sows increased (p < 0.05, quadratic) and the plasma malondialdehyde content of sows decreased (p < 0.05, quadratic) by increasing the dietary net energy concentration. Interestingly, with the increase in dietary net energy concentration, the plasma immunoglobulin M content of sows increased, the milk immunoglobulin M, immunoglobulin G, immunoglobulin A and the percentage of milk fat increased (p < 0.05, linear), and the milk secretory immunoglobulin A content also increased (p < 0.05, linear and quadratic). The milk immunoglobulins and milk fat content of sows fed with net energy concentration of 11.72 MJ/kg were highest. Moreover, there were significant differences in the α-diversity, β-diversity, and relative abundance of gut microbiota in sows fed with different dietary net energy concentrations. At the phylum level, Spirochaetota and Bacteroidota in the gut microbiota of sows were mainly affected by increasing the dietary net energy concentration. Furthermore, the correlation analysis showed that milk immunoglobulin content had a significant negative correlation with the relative abundance of Bacteroidota, and plasma malondialdehyde content also had a significant negative correlation with the relative abundance of Spirochaetota. In summary, these results suggest that increasing the dietary net energy concentration to 11.72 MJ/kg can increase immunological substances in milk, improve milk quality, and alter the composition of gut microbiota in primiparous lactating sows.

Fatty acid-balanced oil improved nutrient digestibility, altered milk composition in lactating sows and fecal microbial composition in piglets

OBJECTIVE

This study aimed to investigate the effects of dietary supplementation of a fatty acid-balanced oil, instead of soybean oil, on reproductive performance, nutrient digestibility, blood indexes, milk composition in lactating sows, and fecal microbial composition in piglets.

METHODS

Twenty-four sows (Landrace×Yorkshire, mean parity 4.96) were randomly allotted to two treatments with twelve pens per treatment and one sow per pen based on their backfat thickness and parity. The experiment began on day 107 of gestation and continued until weaning on day 21 of lactation, lasting for 28 days. The control group (CG) was fed a basal diet supplemented with 2% soybean oil and the experimental group (EG) was fed the basal diet supplemented with 2% fatty acid-balanced oil.

RESULTS

The fatty acid-balanced oil supplementation increased (p<0.05) the apparent total tract digestibility of dry matter, crude protein, and gross energy in sows. The lower (p<0.05) serum high-density lipoprotein cholesterol and albumin levels of sows were observed in the EG on day 21 of lactation. Dietary supplementation with the fatty acid-balanced oil decreased the fat content, increased the immunoglobulin G level, and changed (p<0.05) some fatty acid content in milk. Moreover, the fatty acid-balanced oil supplementation changed (p<0.05) the fecal microbial composition of piglets, where the average relative abundance of Spirochaetota was decreased (p<0.05) by 0.55% at the phylum level, and the average relative abundance of some potentially pathogenic fecal microorganism was decreased (p<0.05) at the species level.

CONCLUSION

The fatty acid-balanced oil improved nutrient digestibility, changed the serum biochemical indices and milk composition of sows, and ameliorated the fecal microbial composition of piglets.

Maternal folic acid and vitamin B12 supplementation during medium to late gestation promotes fetal development via improving placental antioxidant capacity, angiogenesis and amino acid transport

BACKGROUND

Folic acid and vitamin B12 (FV), being B vitamins, not only facilitate the remethylation of homocysteine (Hcy) but also contribute to embryonic development. This study aimed to assess the impact of FV supplementation during late pregnancy on sows' reproductive performance, amino acid metabolism, placental angiogenesis, and related parameters. Twenty primiparous sows at day 60 of gestation were randomly allocated to two groups: a basal diet (CON) group and a group receiving a basal diet supplemented with folic acid at 20 ppm and vitamin B12 at 125 ppb.

RESULTS

The findings revealed that dietary FV supplementation significantly reduced the incidence of intrauterine growth retardation compared to the CON group (P < 0.05). Furthermore, it led to a decrease in the Hcy levels in umbilical cord serum (P < 0.05) and activation of the placental mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway (P < 0.05). Additionally, FV supplementation lowered placental malondialdehyde levels (P < 0.05) and increased the expression of placental thioredoxin (P = 0.05). Moreover, maternal FV supplementation notably elevated placental vascular density (P < 0.05) and the expression of sodium-coupled neutral amino acid transporter 2 (SNAT2) (P < 0.05), as well as amino acid concentrations in umbilical cord blood (P < 0.05).

CONCLUSION

Maternal FV supplementation during medium to late gestation reduced Hcy levels in umbilical cord blood and positively impacted fetal development. This improvement was closely associated with increased placental antioxidant capacity and vascular density, as well as activation of the placental mTORC1-SNAT2 signaling pathway. © 2023 Society of Chemical Industry.

Browning of Mammary Fat Suppresses Pubertal Mammary Gland Development of Mice via Elevation of Serum Phosphatidylcholine and Inhibition of PI3K/Akt Pathway

Mammary fat plays a profound role in the postnatal development of mammary glands. However, the specific types (white, brown, or beige) of adipocytes in mammary fat and their potential regulatory effects on modulating mammary gland development remain poorly understood. This study aimed to investigate the role of the browning of mammary fat on pubertal mammary gland development and explore the underlying mechanisms. Thus, the mammary gland development and the serum lipid profile were evaluated in mice treated with CL316243, a β3-adrenoceptor agonist, to induce mammary fat browning. In addition, the proliferation of HC11 cells co-cultured with brown adipocytes or treated with the altered serum lipid metabolite was determined. Our results showed that the browning of mammary fat by injection of CL316243 suppressed the pubertal development of mice mammary glands, accompanied by the significant elevation of serum dioleoylphosphocholine (DOPC). In addition, the proliferation of HC11 was repressed when co-cultured with brown adipocytes or treated with DOPC. Furthermore, DOPC suppressed the activation of the PI3K/Akt pathway, while the DOPC-inhibited HC11 proliferation was reversed by SC79, an Akt activator, suggesting the involvement of the PI3K/Akt pathway in the DOPC-inhibited proliferation of HC11. Together, the browning of mammary fat suppressed the development of the pubertal mammary gland, which was associated with the elevated serum DOPC and the inhibition of the PI3K/Akt pathway.