Betaine and Isoquinoline Alkaloids Protect against Heat Stress and Colonic Permeability in Growing Pigs.

Hieu Huu Le,Weicheng Zhao,Valeria Artuso-Ponte,Eva Vidacs,John Barton Furness,Deborah Jayne Phillips,Majid Shakeri,Jeremy James Cottrell,Frank Rowland Dunshea,Hafiz Ansar Rasul Suleria,Rachel Mai Mcquade

doi:10.3390/antiox9101024

Abstract

Heat stress (HS) compromises productivity of pork production, in part as a result of increased oxidative stress and inflammatory responses, particularly within the gastrointestinal tract. This study aimed to investigate whether plant-derived betaine and isoquinoline alkaloids could ameliorate HS in pigs. Fifty female Large White × Landrace grower pigs, which were acclimated to control (CON), control plus betaine (BET), or control plus isoquinoline alkaloids (IQA) diets for 14 days were then exposed to heat stress or thermoneutral condition. Both BET and IQA partially ameliorated increases in respiration rate (p = 0.013) and rectal temperature (p = 0.001) associated with HS conditions. Heat stress increased salivary cortisol concentrations and reduced plasma creatinine, lactate, and thyroid hormone concentrations. Heat stress increased colon FD4 permeability, which was reduced by IQA (p = 0.030). Heat stress increased inflammation in the jejunum and ileum, as indicated by elevated interleukin-1β (p = 0.022) in the jejunum and interleukin-1β (p = 0.004) and interleukin-8 (p = 0.001) in the ileum. No differences in plasma total antioxidant capacity (TAC) were observed with HS, but betaine increased plasma TAC compared to IQA. Dietary BET increased betaine concentrations in the jejunum, ileum (p < 0.001 for both), plasma, liver, kidney (p < 0.010 for all), urine (p = 0.002) and tended to be higher in muscle (p = 0.084). Betaine concentration was not influenced by HS, but it tended to be higher in plasma and accumulated in the liver. These data suggest that betaine and isoquinoline alkaloids supplementation ameliorated consequences of heat stress in grower pigs and protected against HS induced increases in colonic permeability.

Highlights

Pigs are sensitive to heat stress (HS) as they lack functional sweat glands to facilitate heat loss via an evaporative pathway from the skin
There was an interaction between environmental condition and time of the day (p < 0.001) such that respiration rate (RR) was increased to a greater extent over the day in pigs subjected to HS compared to those housed in TN condition (Figure 1A)
There was a significant interaction between HS and diet (p = 0.013) such that RR were lower in pigs given BET or isoquinoline alkaloids (IQA) and subjected to HS but not in those housed in TN condition (Figure 1A)

Summary

Introduction

Pigs are sensitive to heat stress (HS) as they lack functional sweat glands to facilitate heat loss via an evaporative pathway from the skin. Pair feeding studies in other species have shown that only half of the lost productivity can be explained by reductions in feed intake alone [1] The reasons for this further loss in productivity are multi-faceted but include factors such as disruption of the lining of the gastrointestinal tract (GIT). The resultant reduced blood flow to the GIT is insufficient to meet metabolic needs and precipitates oxidative stress and loss of the villus epithelium, exposing the lamina propria [5,6]. This results in increased permeability to endotoxins and inflammation [7,8]

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