Effects of peat feeding on the performance and health status of fattening pigs and environmentally derived mycobacteria

The purpose of the present study was to investigate the effects of feeding peat as a supplement in the period after weaning on the performance and health status of pigs. Also to assess the risk of the development of tuberculous lesions in the lymph nodes and parenchymatous organs, caused by conditionally pathogenic mycobacteria present in peat. Twenty Large White × Landrace pigs in equal numbers of barrows and gilts (mean live weight 18.0 ± 1.7 kg) were used in the experiment. The experimental group was fed a diet containing commercial underground peat in the dose of 80 g peat/kg dry matter for 30 days. Subsequently, they were fed an identical diet with the control group without peat for 60 days. A short-time feeding peat did not significantly affect the growth and performance of pigs. From day 21, a statistically highly significant (P < 0.01) increase in the consumption of the experimental diet was recorded, however, without a positive effect on the growth of experimental animals. The conversion of the peat containing diet was comparable to the conversion of the control diet. It follows from the results of biochemical analysis of blood that peat feeding for 30 days did not adversely affect the metabolic profile and health status of experimental animals. No tuberculous or tuberculoid lesions in lymph nodes or parenchymatous organs were detected in any of 20 slaughtered animals. Despite that, mycobacteria were isolated from 10 (25.0%) tissues of 5 (50.0%) pigs from the experimental group. One isolate was identified as Mycobacterium avium subsp. hominissuis (IS901- and IS1245+). Seven of nine isolates were determined as conditionally pathogenic atypical mycobacteria: M. fortuitum (n = 2) and M. xenopi (n = 5). It follows from the present results that feeding of a peat supplemented diet to pigs may be considered as economically non-effective and due to the findings of mycobacteria as risky.