Sickness can change our mood for the worse, leaving us sad, lethargic, grumpy and less socially inclined. This mood change is part of a set of behavioural symptoms called sickness behaviour and has features in common with core symptoms of depression. Therefore, the physiological changes induced by immune activation, for example following infection, are in the spotlight for explaining mechanisms behind mental health challenges such as depression. While humans may take a day off and isolate themselves until they feel better, farm animals housed in groups have only limited possibilities for social withdrawal. We suggest that immune activation could be a major factor influencing social interactions in farm animals, with outbreaks of damaging behaviour such as tail biting as a possible result. The hypothesis presented here is that the effects of several known risk factors for tail biting are mediated by pro-inflammatory cytokines, proteins produced by the immune system, and their effect on neurotransmitter systems. We describe the background for and implications of this hypothesis.

Deoxynivalenol (DON) is one of the most prevalent Fusarium mycotoxins in grain and can cause economic losses in pig farming due to reduced feed consumption and lower weight gains. Biodetoxification of mycotoxins using bacterial strains has been a focus of research for many years. However, only a few in vivo studies have been conducted on the effectiveness of microbial detoxification of fusariotoxins. This study was therefore aimed at investigating the effect of a feed additive containing the bacterial strain Coriobacteriaceum DSM 11798 (the active ingredient in Biomin® BBSH 797) on growth performance and blood parameters, as well as uptake and metabolism of DON, in growing pigs. Forty-eight crossbred (Landrace-Yorkshire/Duroc-Duroc) weaning pigs were fed with pelleted feed made from naturally contaminated oats, with DON at four concentration levels: (1) control diet (DON < 0.2 mg kg⁻¹), (2) low-contaminated diet (DON = 0.92 mg kg⁻¹), (3) medium-contaminated diet (DON = 2.2 mg kg⁻¹) and (4) high-contaminated diet (DON = 5.0 mg kg⁻¹) and equivalent diets containing DSM 11798 as feed additive. During the first 7 days of exposure, pigs in the highest-dose group showed a 20–28% reduction in feed intake and a 24–34% reduction in weight gain compared with pigs in the control and low-dose groups. These differences were levelled out by study completion. Towards the end of the experiment, dose-dependent reductions in serum albumin, globulin and total serum protein were noted in the groups fed with DON-contaminated feed compared with the controls. The addition of DSM 11798 had no effect on the DON-related clinical effects or on the plasma concentrations of DON. The ineffectiveness of the feed additive in the present study could be a consequence of its use in pelleted feed, which might have hindered its rapid release, accessibility or detoxification efficiency in the pig’s gastrointestinal tract.

Deoxynivalenol (DON) contamination of feed may result in reduced growth, feed refusal, immunosuppression, and health problems in swine. Piglets can be exposed to DON via placenta before birth and via milk during lactation. The extent of early-life exposure of piglets to DON is, however, not fully known. This study was therefore aimed at investigating DON uptake in sows fed with naturally contaminated diets, DON transfer across placenta during late gestation, and transfer of DON to piglets via colostrum and milk. Forty-four crossbred sows were evaluated from day 93 ± 1 of gestation until weaning of piglets and fed with feed made from naturally DON-contaminated oats at three concentration levels: (1) control (DON < 0.2 mg/kg), (2) DON level 1 (1.4 mg DON/kg), and (3) DON level 2 (1.7 mg DON/kg). The transfer of DON to the piglets was evaluated in 15 sows, with repeated sampling of blood and milk from the sows and blood samples from five piglets of each litter. The piglet/sow plasma DON ratio and milk/plasma (M/P) DON ratio in sows were calculated to estimate the degree of transfer. Piglet/sow plasma ratios were 2.14 at birth, 2.30 within 12–36 h after parturition, 0.08 on day 7, 0.16 on day 21, and 0.20 at weaning. M/P ratios were 0.92, 1.11, 0.94, 1.21, and 0.90, respectively. The results indicate that DON is efficiently transferred across placenta and into milk. However, the low piglet/sow plasma ratios at mid-lactation to weaning indicate that the piglets were most strongly exposed to DON in early life, despite the high M/P ratios and efficient secretion of DON in milk throughout the entire lactation.

The most prevalent Fusarium mycotoxin in grains is deoxynivalenol (DON). Contamination of swine feed with DON can result in reduced consumption and poor growth performance. Gestating and lactating sows need sufficient feed intake for fetus development during late gestation and milk production and body maintenance during lactation. Therefore, there is considerable concern in modern piglet production about the effects of DON contamination in sow feed. Most previous studies in sows have been done under experimental conditions, with DON levels ≥2.8 mg/kg feed. The aim of the current field trial was to investigate the effects of feeding grains that are naturally contaminated with more realistic levels of DON on sows during late gestation and lactation. In a commercial, high-yield specific pathogen-free piglet production unit, 45 Norwegian Landrace × Yorkshire sows were fed three diets from 93 ± 1 days of gestation until weaning of the piglets, and average daily feed intake (ADFI), body weight (BW), production and reproduction performance, as well as sow blood parameters were recorded. Diets were made from naturally contaminated oats, with three concentration levels: 1) control (DON < 0.2 mg/kg), 2) DON level 1 (1.4 mg DON/kg), and 3) DON level 2 (1.7 mg DON/kg). Sows that were fed DON level 1 and 2 diets showed a 4–10% reduction in feed consumption during lactation, compared with sows in the control group. However, the DON-contaminated diets did not significantly affect sow BW or backfat thickness. Similarly, there were neither effects on production or reproduction performance, nor on blood parameters in the sows. The effects on skin temperature were variable. Naturally contaminated diets with realistic, moderately increased DON levels, fed during late gestation and lactation in a modern high-yield piglet production farm, had limited effects on sow health and production.