Gilt retention challenges can result in a parity profile skewed to younger females in the breeding herd. We know that there are differences in reproductive efficiency and disease control in gilts vs sows. Gilt progeny (GP) are already known to have lower birth, weaning and slaughter weights than sow progeny (SP). Disease control issues are greater in Gilt progeny (GP). GP can be more susceptible to disease due to higher pathogen shedding (infectious pressure) coming from gilts (especially at farrowing). Gilt progeny can also be more challenged by disease due to the reduced rates of passive immunity supplied by gilts via colostrum and milk. One area, however, that is less well researched is the physical attributes of gilt progeny that can contribute to increased health challenges. The gastrointestinal barrier is a semipermeable structure that allows the uptake of essential nutrients. The gastrointestinal barrier also allows for the detection of immune stimulating antigens that exist within the intestinal lumen while at the same time restricting the entry pathogenic molecules and bacteria into the body. These Australian researchers wanted to quantify changes in gastrointestinal barrier function in GP vs SP at four timepoints: birth (~0 hours), 24 hours after birth (24 h), 1 day preweaning (PrW), and 1 day postweaning (PoW). Gastrointestinal barrier integrity was quantified by measuring transepithelial resistance (TER), macromolecular permeability, the abundance of pro-inflammatory or cytokine proteins (IL-8, IL-1β, and TNF-α) and tight junction proteins (claudin-2 and -3). Paracellular permeability (Papp) was characterized using a dual tracer approach using FD4 and T150 labeled dextrans as way of measuring barrier integrity or the tightness of intestinal epithelial junctions.
The researchers found the following:
- In the birth cohort, at the initiation of feeding, there was a reduction of paracellular permeability (leaking) by 24 hours after birth that is consistent with maturation of the gut mucosal lining (P = 0.058) This was accompanied by increased cytokine abundance as evidenced by elevations in TNF-α and IL-1β. The researchers did note that gilt progeny had increased IL-8 abundance for jejunum (P=0.001) and ileum (P= 0.063) at birth vs 24 h overall.
- In the weaning cohort, jejunal (P = 0.05) and ileal (P= 0.022) permeability based on tracking FD4 was higher in gilt progeny while only higher ileal T150 was observed in gilt progeny (P = 0.032) when compared to sow progeny.
- Ileal claudin-2 tight junction protein abundance tended to be higher in sow progeny overall (P = 0.063), but researchers noted that in gilt progeny ileal claudin-2 expression was upregulated at weaning while no change was observed in sow progeny at the time of weaning (P = 0.043).
Take Home Message:
- Overall the researchers concluded from this study that the gastrointestinal tract of gilt progeny have poorer adaptation to early life events.
- The response to weaning was particularly more pronounced in the gilt progeny and the researchers suggest that this challenge is likely to contribute to poorer postweaning growth.
- These findings can be added to the already long list of challenges in raising gilt progeny. This challenge is even bigger during a gilt start or when gilt retention is a challenge and the sow herd parity is skewed to increased numbers of gilts.
Reference: Udani A Wijesiriwardana , John R Pluske , Jessica R Craig , John B Furness , Mitchell Ringuet , Linda J Fothergill, Frank R Dunshea , Jeremy J Cottrell A comparative analysis of gastrointestinal tract barrier function and immune markers in gilt vs. sow progeny at birth and weaning J Anim Sci . 2024 Jan 3:102:skae054. doi: 10.1093/jas/skae054.
