Effect of lipopolysaccharide-induced immune stimulation and maternal fish oil and microalgae supplementation during late pregnancy on nursery pig hypothalamic–pituitary–adrenal function1

Abstract

The present study used Escherichia coli lipopolysaccharide (LPS) to investigate whether maternal immune challenge during late gestation altered programming of the offspring hypothalamus and hypothalamic–pituitary–adrenal axis (HPAA). In addition, interactions of maternal diet, supplementation with fish oil (FO) or microalgae (AL), and complex vs. simple weaning diets were investigated. Briefly, Landrace × Yorkshire sows (N = 48) were randomly assigned to diets supplemented with FO, AL, or a standard gestation control diet (CON) from day 75 of gestation (gd 75) until parturition. On gd 112, half the sows from each dietary treatment were immune challenged with LPS (10 μg/kg BW) or saline as a control. At 21 d postpartum, the offspring were weaned, and half the animals from each maternal treatment were allocated to either a complex or simple weaning diet. At 28 d postpartum, the offspring’s hourly fever and 2-h cortisol responses to LPS immune challenge (40 μg/kg BW) were measured to assess hypothalamus and HPAA function. Results indicated that the maternal temperature of sows on the FO diet returned to baseline levels faster than sows on the AL and CON diets after LPS immune challenge (P < 0.05). In contrast, there was no difference in the maternal cortisol response across the dietary treatments (P > 0.10). Regardless of the dietary treatments, the maternal LPS immune challenge induced a greater cortisol response in male offspring (P = 0.05) and a greater fever response in female offspring (P = 0.03) when they were LPS immune challenged post-weaning. Male offspring from LPS-immune-challenged sows fed the FO and AL diets had a greater fever response than male offspring from the maternal CON diet group (P ≤ 0.05). Last, no effect of the complex or simple weaning diets was observed for the nursery pig cortisol or fever responses to LPS immune challenge. In conclusion, LPS immune challenge during late pregnancy altered responsiveness of the offspring hypothalamus and HPAA to this same microbial stressor, and a sex-specific response was influenced by maternal dietary supplementation with FO and AL.

Effects of Dietary Fat Sources during Late Gestation on Colostrum Quality and Mammary Gland Inflammation in Lipopolysaccharide-Challenged Sows

“…In addition, maternal FO diets appeared to alleviate LPS-induced decreased weight gain of piglets and colostrum production, although these effects were not statistically significant, suggesting that feeding FO to sows as a source of n-3 PUFA may play an important role in regulating prenatal maternal stress. Similarly, a recent study demonstrated that maternal n-3 PUFA dietary supplementation attenuated the sow fever response to inflammatory stress challenges [14].…”

“…A total of sixty multiparous sows (Landrace × Yorkshire; 3 to 5 of parity) were randomly selected and assigned into three dietary treatment groups (3% SO, 3% CO and 3% FO) based on backfat thickness and body weight (n = 20 per group) using a randomized complete block design. The dose of 3% was included as previously described, which showed beneficial effects of FO on the hypothalamic-pituitary-adrenal function in sows and offspring [14]. All sows in the present experiment were artificially inseminated by pooled semen from three Duroc boars .…”

Effect of algae or fish oil supplementation and porcine maternal stress on the adrenal transcriptome of male offspring fed a low-quality protein diet

“…This study is the first to investigate the effects of maternal AL and FO supplementation in combination with maternal LPS challenge in late gestation on adrenal mRNA expression in swine. The animals in this study were previously used to the assess acute-phase response to an LPS challenge ( You et al., 2019 ). The results from this study showed differential effects of maternal gestation dietary treatment and maternal LPS status, leading to the hypothesis that the maternal treatments would also influence the adrenal transcriptome of the offspring.…”

“…Following the LPS challenge, adrenal tissue was selected from 24 of the male offspring ( n ​= ​4/maternal gestation dietary treatment and maternal LPS status). The adrenal gland was selected for microarray analysis due to previously observed differences in the offspring cortisol response following LPS challenge ( You et al., 2019 ). Total RNA was extracted from 20-30 ​mg of adrenal tissue using the Qiagen RNeasy extraction kit (Qiagen, Valencia, CA, USA) as per the manufacturer’s specifications.…”

“…Previously, ovine research has shown that the combination of maternal dietary n-3 PUFA supplementation and an LPS challenge can differentially modulate the offspring stress response, as characterized by fever and cortisol responses, when offspring are later exposed to an LPS challenge ( Fisher-Heffernan et al., 2015 ; Fisher et al., 2014 ; You et al., 2019 ). In pigs, there appear to be differences in the stress response between male and female offspring, with male offspring being more sensitive than female offspring to maternal AL or FO dietary supplementation and/or maternal LPS exposure ( You et al., 2019 ). In addition, more pronounced differences were observed among these male offspring from differing maternal treatments.…”