Reproductive performance and immune status of sows fed diets containing Olextra 1200 during lactation

The olive oil tree (Olea europaea L.) contains hydrophilic and lipophilic bioactive compounds, which include flavones, phenolic acids, phenolic alcohols, secoiridoids, and hydroxycinnamic acid derivatives. These bioactive compounds have anti-inflammatory, antimicrobial, and antioxidant properties, and therefore, olive-derived plant bioactive compounds may reduce chronic inflammation and intestinal integrity in pigs. Therefore, olive-derived plant bioactive compounds, such as Olextra 1200, may improve health and prevent disease by inhibiting B cell activation and cytokine expression. However, there is a lack of data demonstrating effects of olive extracts on reproductive performance of sows and their offspring. Therefore, the objective of this experiment was to test the hypothesis that dietary supplementation of Olextra 1200 increases reproductive performance as well as the immune status of sows.

Experimental design

A corn-based lactation control diet was formulated, and an additional diet was formulated by adding 0.20% Olextra 1200 to the control diet. Forty-two sows (parity ≥ 1) were allotted to a randomized complete block design with three blocks of 14 sows and 7 sows per treatment in each block for a total of 21 sows per treatment. Sows were housed in farrowing crates from day 108 of gestation when feeding of experimental diets was initiated. Feed intake was restricted from day 108 to farrowing, but sows had free access to experimental diets and water throughout the lactation period. On day 114 of gestation and on day 14 of lactation, blood samples were collected from the vena cava of sows to analyze for regulatory T cells. Sow milk was collected on day 1 (colostrum) and day 14 of lactation. Sows were weaned on day 20 ± 1.


No differences were observed between sows fed the control diet and the diet with Olextra 1200 on the following measurements: Body weight loss during lactation, feed intake during lactation, days between weaning and estrus, estimated total and daily milk yields, number of pigs born per litter, number of pigs born alive per litter, number of still born pigs per litter, number of mummified pigs per litter, and number of pigs weaned per litter (Table 1).  However, the number of pigs per litter after cross-fostering and the total litter weight after cross-fostering increased when sows were fed the Olextra 1200 diet.

Milk urea nitrogen (MUN) can be used as an indicator of amino acid utilization efficiency and, therefore, provides an estimation of the amount of N loss after absorption. The concentration of MUN in colostrum was greater (P < 0.05) in sows fed the control diet compared with sows fed the diet with Olextra 1200, which indicates that sows fed the Olextra diet were more efficient in utilizing amino acids (Table 2). Therefore, it is possible that addition of Olextra to diets resulted in improved colostrum quality, which supports the observed increase in total litter weight when sows were fed the diet with Olextra. However, Olextra did not influence concentrations of other components in colostrum of sows. No differences were observed in the composition of milk between treatments.

Cytotoxic T cells (e.g., CD8 T cells) are responsible for immune defense against intracellular pathogens such as viruses and bacteria. During a viral infection, CD8 T lymphocytes get activated to kill virus-infected cells and produce antiviral cytokines. The frequency of CD8 T cells on day 114 of gestation decreased (P < 0.05) when Olextra 1200 was added to the diet (Table 3). However, no other effects of dietary treatment on regulatory T cells on d 114 of gestation were observed. On day 13 after farrowing, the frequency of CD25 + FoxP3 neg (of CD8 T cells) tended to be reduced (P < 0.10) in sows fed the diet with Olextra 1200.

Key Points

  • Sows fed a diet containing olive-derived bioactive compounds may have improved colostrum quality.
  • Supplementation with olive-derived bioactive compounds may suppress the occurrence of pathogen infection in lactating sows by reducing cytotoxic T cells.

Table 1. Performance of sows and litters fed experimental diets during lactation1

1Data are means of 21 observations for the control treatment and 20 observations for the Olextra treatment.

2Olextra = Olextra 1200.

3Estimated milk yield was calculated as 4 g milk per 1 g of litter body weight gain (Close and Cole, 2000).

Table 2.  Composition of colostrum and milk samples from sows fed experimental diets1

1Data are means of 21 observations for the control treatment and 20 observations for the Olextra treatment.

 2Olextra = Olextra 1200.

3Free fatty acids as a % of the fat %.

4MUN = Milk urea N

Table 3. Frequency of regulatory T cells in the blood collected from sows fed experimental diets1

1Data are means of 21 observations for the control treatment and 20 observations for the Olextra treatment.

 2Olextra = Olextra 1200.

3CD = cluster of differentiation 4; FOXP3 = forkhead box protein 3.

4Regulatory T cells are the sum of CD25 + FoxP3 + SP CD4 T cells, CD25 + FoxP3 + DP CD4 T cells, and CD25 + FoxP3 + DP CD8 T cells.