Effects of dietary fish meal and soybean meal on the ovine innate and acquired immune response during pregnancy and lactation

Abstract

In recent years, livestock producers have been supplementing animal diets with fish meal (FM) to produce value-added products for health conscious consumers. As components of FM have unique neuroendocrine-immunomodulatory properties, we hypothesize that livestock producers may be influencing the overall health of their animals by supplementing diets with FM. In this study, 40 pregnant ewes were supplemented with rumen protected (RP) soybean meal (SBM: control diet) or RP FM, commencing gestation day 100 (gd100), in order to evaluate the impact of FM supplementation on the innate and acquired immune response and neuroendocrine response of sheep during pregnancy and lactation. On gd135, half the ewes from each diet (n 5 10 FM, n 5 10 SBM) were challenged iv with lipopolysaccharide (LPS) to simulate a systemic bacterial infection and the febrile, respiratory and neuroendocrine responses were monitored over time; the other half (n 5 10 FM, n 5 10 SBM) of the ewes received a saline injection as control. On lactation day 20 (ld20), all ewes ( n 5 20 FM, n 5 20 SBM) were sensitized with hen egg white lysozyme (HEWL) and the serum haptoglobin (Hp) response was measured over time. The cutaneous hypersensitivity response (CHR) to HEWL challenge was measured on ld30 ( n 5 20 FM, n 5 20 SBM), and blood samples were collected over time to measure the primary and secondary immunoglobulin G (IgG) response to HEWL. There was an attenuated trend in the LPS-induced febrile response by the FM treatment when compared with the SBM treatment ( P 5 0.06), as was also true for the respiratory response (P 5 0.07), but significant differences in neuroendocrine function (serum cortisol and plasma ACTH) were not observed between treatments. Basal Hp levels were significantly lower in the FM supplemented ewes when compared with the SBM supplemented ewes ( P , 0.01), and the Hp response to HEWL sensitization differed significantly over time between treatments (P , 0.01). The CHR to HEWL was also significantly attenuated in the FM treatment compared with the SBM (P , 0.01); however, treatment differences in the primary and secondary IgG responses to HEWL were not observed. These results indicate that FM supplementation differentially affects the innate and acquired immune responses in pregnant and lactating sheep compared with a typical SBM diet of commercial flocks. The long-term implications of this immunomodulation warrant further investigation.

Effect of reducing the ratio of omega-6-to-omega-3 fatty acids in diets of low protein quality on nursery pig growth performance and immune response

“…In the current study, pigs that received nursery diets with fish oil supplemented between 1.25% and 5% (ω-6-to-ω-3 fatty acid ratio between 5:1 and 1:1) had reduced concentrations of the Hp serum acute-phase protein compared to those fed 0% fish oil. This is consistent with other reports in pigs (Bazinet et al, 2004), ewes (Stryker et al, 2013), and humans (Ernst et al, 1991) fed diets with reduced ω-6-to-ω-3 fatty acid ratios. During immune system stimulation, cytokines are released into circulation by inflammatory cells such as neutrophil granulocytes and macrophages, which induce the liver to produce acute-phase proteins such as Hp.…”

Maternal supplementation with fishmeal protects against late gestation endotoxin-induced fetal programming of the ovine hypothalamic-pituitary-adrenal axis

“…It was evident based on the cortisol responses from this study that there were endotoxin-induced changes in the HPAA response of the offspring as well as alterations based on the PUFA diet that mothers were consuming. It should be noted that there were no differences reported in the ewes' ACTH or cortisol response to endotoxin challenge across the PUFA treatment groups on gd135 of this trial reported in Stryker et al 27 However, the ewes did demonstrate a difference in their fever response, with FM + LPS ewes having an attenuated fever response compared with the SM + LPS ewes. 27 Results from the present study demonstrated that female offspring born to mothers supplemented with FM and challenged with endotoxin during late gestation had the greatest and quickest cortisol response to weaning stress as well as the endotoxin challenge compared with all other treatment groups.…”

“…It should be noted that there were no differences reported in the ewes' ACTH or cortisol response to endotoxin challenge across the PUFA treatment groups on gd135 of this trial reported in Stryker et al 27 However, the ewes did demonstrate a difference in their fever response, with FM + LPS ewes having an attenuated fever response compared with the SM + LPS ewes. 27 Results from the present study demonstrated that female offspring born to mothers supplemented with FM and challenged with endotoxin during late gestation had the greatest and quickest cortisol response to weaning stress as well as the endotoxin challenge compared with all other treatment groups. This was surprising as n-3 PUFAs have been shown to reduce pro-inflammatory cytokines (such as TNF-α, IL-1 and IL-6) that can activate the HPAA 16,31 and therefore, it was expected that offspring born to mothers supplemented with SM and challenged with LPS would have the greatest cortisol response.…”

“…Ewes were allocated to either a diet rich in soybean meal (SM) representing n-6 PUFA (control diet), or a diet rich in FM representing n-3 PUFA beginning on day 100 of gestation (gd100; gestation period 145 days) and continuing throughout lactation; the diet composition is provided in Stryker et al, 2013. 27 Ewes were offered feed twice a day totaling 2.64 kg of feed/day during gestation and 3.90 kg feed/day during lactation. Nutrient requirements were based on both the weight and age of the ewes, and were calculated using the Cornell Net Carbohydrate and Protein System for sheep (Cornell University, Ithaca, NY).…”

Fishmeal supplementation during ovine pregnancy and lactation protects against maternal stress-induced programming of the offspring immune system

“…On gd135, half of each the ewes from each dietary treatment group were endotoxin challenged with a 2 ml i.v bolus of 1.2 μg/kg body weight of lipopolysaccharide (LPS) from Escherichia coli 055:B5 (Sigma-Aldrich, Oakville, Ontario) dissolved in saline, or a 2 ml bolus of saline for control (CON). Health status such as febrile response, respiration rate and haptoglobin concentrations of these ewes were previously reported in Stryker et al [ 30 ]. The treatment groups and animal numbers are as follows SM + LPS ( n = 12), SM + CON ( n = 13), FM + LPS ( n = 14) or FM + CON ( n = 14).…”