Mycobacteria in peat used as a supplement for pigs: failure of different decontamination methods to eliminate the risk

Abstract

Peat used as a feed supplement for piglets has favourable dietetic qualities; however, its frequent contamination with potentially pathogenic mycobacteria (PPM) has been shown to pose a potential risk to piglet health. The purpose of the present study was to investigate possible ways of devitalising mycobacteria. Examination of 118 samples from various types of commercially available peat (natural peat, packed peat for horticulture and specially processed peat intended for piglet feeding) showed that PPM were present in 84 (71.1%) samples. Mycobacterium avium subsp. hominissuis (82.1%) was the most frequent mycobacterial isolate. In addition, from a natural locality where peat is mined and stored in large piles for up to four months, mycobacteria were detected in peat samples collected from the surface and from up to 25 cm in depth. We used different physical and chemical procedures for peat decontamination (peracetic acid, formaldehyde, steam, and microwave radiation) in attempting to devitalise the mycobacteria in peat. We found that PPM can be reliably devitalised with 1.0% peracetic acid, or 5.0% formaldehyde. However, under field conditions, when using bulk amounts of peat, none of the above procedures were shown to be suitable. Based on these results, the feeding of peat to piglets is confirmed as a high-risk practice.

Nontuberculous Mycobacteria as Sapronoses: A Review

“…hominissuis was the most isolated causative agent in several studies [ 121 , 122 , 123 , 124 , 125 , 126 ]. It is very difficult to remove NTM from naturally infected peat by any disinfection procedure currently practiced including treatment with high temperatures [ 127 ].…”

Nontuberculous Mycobacteria: Ecology and Impact on Animal and Human Health

“…The second extended edition of the book, published in 2009, comprehensively summarizes the information available at the time on the ecology of mycobacteria and their impact on human and animal health [ 2 ]. Two of the four co-editors of this book are deceased: Jindrich Kazda (1927–2018) and Karel Hruska (1935–2022), while Joseph Oliver Falkinham, III [ 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ] and Ivo Pavlik [ 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ] can be considered as successors in this field of research.…”

Zinc oxide enriched peat influence Escherichia coli infection related diarrhea, growth rates, serum and tissue zinc levels in Norwegian piglets around weaning: five case herd trials

“…Independent studies have stated that the effects of batches containing dietary humic substances are variable, warranting further investigation [39, 46]. An important prerequisite when applying peat supplementation to animals, is the monitoring of potentially pathogenic mycobacteria sometimes present in batches of peat preparations [47, 48]. These case herd trials aimed to explore the effects of different ZnO sources and ZnO levels in peat preparations on pre- and post-weaning fecal consistency and weight gain.…”