Non-invasive smooth muscle electromyography (SMEMG) as a novel monitoring technology of the gastrointestinal tract of awake, free-moving pigs-A pilot study.

Katalin Nagy,Hedvig Fébel,György Grosz,Róbert Gáspár,Kálmán Ferenc Szűcs,George Bazar,Tamás Tóth

doi:10.1371/journal.pone.0257311

Katalin Nagy, Hedvig Fébel + Show 5 more

Open Access

https://doi.org/10.1371/journal.pone.0257311

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Abstract

There are several mathematical models and measurements to determine the efficiency of the digestibility of different feedstuffs. However, there is lack of information regarding the direct methods or measurement techniques used to analyse the physical response of the different parts of the gastrointestinal tract (GIT) of growing pigs to different diets. Smooth muscle electromyography (SMEMG) is a non-invasive method for the measurement of gastrointestinal myoelectrical activity. In the present study, SMEMG methodology has been adapted from laboratory rats to pigs, and the effects of feedstuffs with control (CTR) or experimentally increased (EXP) amounts of fibre were investigated on gastrointestinal tract motility. Nine barrow pigs ((Danish Landrace × Danish Yorkshire) × Danish Duroc) were used (30 ± 3 kg), and their CTR and EXP feedstuffs contained 29 and 49 g/kg crude fibre (CF), respectively. Myoelectric activities of the stomach, ileum and caecum were detected in the awake pigs by a pair of electrodes. The recorded myoelectric signals were analysed with fast Fourier transformation (FFT), and the spectra were expressed in GIT section-specific cycles per minutes (cpm) values and the maximum power spectrum density (PsDmax). A significant increase (P < 0.001) was observed in the value of the PsDmax of the small intestine (20-25 cpm) as a consequence of the EXP diet. The PsDmax values of the stomach (3-5 cpm) and large intestine (1-3 cpm) did not show any significant change in pigs fed the EXP diet. As a direct and non-invasive method, SMEMG is suitable for the rapid evaluation of the effects of diets with different fibre contents on the GIT of non-anaesthetised, free-moving pigs.

Highlights

Digestion is affected by many factors, such as the physical and chemical characteristics of feed [1], feed processing [2], different animal factors and nutritional levels [3]
The changes in the myoelectric activity of the gastrointestinal tract (GIT) were followed with Smooth muscle electromyography (SMEMG) in parallel with the mechanical contractions in anaesthetised rats using a strain gauge tool. Another SMEMG experiment was carried out in awake rats, measuring GIT activity under normal and stressed conditions [19]. Based on these earlier findings, our study primarily aims to develop the non-invasive SMEMG measurement applied for pigs, and to identify and analyse myoelectric signals of the different GIT segments in growing and awake pigs
A durable SMEMG device was successfully tested as a portable tool for the non-invasive monitoring of gastrointestinal myoelectrical activity in awake, free-moving, growing pigs

Summary

Introduction

Digestion is affected by many factors, such as the physical and chemical characteristics of feed [1], feed processing [2], different animal factors and nutritional levels [3]. Ileal or total tract digestion models have been developed for pigs [6,7,8], in which digestibility is predicted by separately quantifying transit time, endogenous secretions, degradation, absorption and microbial fermentation. These predictions are required because of the limited quantitative information concerning the digestion and transit kinetics in the different segments of the GIT of pigs. The gastric emptying process is represented by different masses of feedstuff or segments of the digestive tract [6,7,8]

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