Association Between Tail-Biting and Intestinal Microbiota Composition in Pigs

Abstract

Tail-biting (TB) in pigs is a serious behavioral disorder. It is an important challenge in swine production as it impacts animal welfare and health and the economics and safety of the pork meat supply chain. To prevent TB, approaches including enrichment material and tail docking are proposed but none are optimal. Nutrition appears to be an important factor in TB behavior, perhaps by modulating the intestinal microbiota (IM). Our aim was to assess the association between TB behavior and IM in pigs through comparisons of IM in groups of biter, bitten and non-biter/non-bitten pigs. Each group composed of 12 pigs was formed at the beginning of the growing/finishing phase based on a target behavior analysis centered on TB behavior for the biter group and a score of damages caused to the tail for the bitten group. Blood and fecal samples were collected from each pig during a TB episode, at time 0, t0, and when the TB episode was considered finished, 4 weeks later, at time 1, t1. Serum cortisol level was determined by ELISA and used as an indicator of stress. The pig's fecal microbiota was analyzed from DNA extracted from freshly collected fecal matter using amplicon sequencing of the V4 hypervariable region of the 16S rRNA gene. Serum cortisol levels were significantly higher in either the biter or bitten pig groups compared to the negative control group (p = 0.02 and p = 0.01, respectively). The microbiota alpha-diversity was not significantly different between all groups, biter, bitten and negative control. Analyses of beta-diversity, however, revealed a significant difference between either the biter or the bitten group in comparison to the non-biter/non-bitten negative control group in terms of structure and composition of the microbiota. Lactobacillus were significantly more abundant in the negative control group compared to the two other groups (p = 0.001). No significant difference was revealed between the biter and bitten groups. Quantitative real-time PCR (qPCR) confirmed that lactobacilli were more abundant in the negative control group. Our study indicates that TB behavior is associated with the IM composition in pigs.

The gut microbiota and microbial metabolites are associated with tail biting in pigs

“…In agreement with the study by Rabhi et al 27 , we identified taxa differences between biter pigs and controls. Rabhi et al, reported lower Lactobacillus in the biter pigs, and a similar reduction in the abundance of Lactobacillus has also been reported in feather pecking hens 58 .…”

“…The higher relative abundance of Firmicutes in the tail biter pigs was primarily driven by the higher abundance of the families Lachnospiraceae, Ruminococcaceae and Clostridiales Family XIII. Our results are partly in line with the so far only published paper on gut microbiota composition and tail biting in pigs 27 . In line with their results, we also found the highest similarity in microbiota composition between the biters and the victims and the largest differences between biters and controls.…”

“…Furthermore, the multiple stressors experienced already from an early age (e.g., weaning and separation from the dam, castration, frequent mixing with unfamiliar animals) may pose an increased risk of developing an unbalanced gut microbiota. A first explorative study has shown that pigs involved in tail biting had a different microbiota composition compared to pigs not involved in tail biting, and this difference was primarily dependent on a reduced abundance of Lactobacillus in the animals involved in tail biting 27 .…”

“…Furthermore, the multiple stressors experienced already from an early age (e.g., weaning and separation from the dam, castration, frequent mixing with unfamiliar animals) may pose an increased risk of developing an unbalanced gut microbiota. A first explorative study has shown that pigs involved in tail biting had a different microbiota composition compared to pigs not involved in tail biting, and this difference was primarily dependent on a reduced abundance of Lactobacillus in the animals involved in tail biting 27 .One of the pathways for crosstalk between the gut and the brain is through the production of microbial metabolites that have neuroactive properties. Short-chain fatty acids (SCFA) are the main metabolites produced in the large intestine by anaerobic bacterial fermentation of dietary fibre 28 .…”

Evolution of Pig Fecal Microbiota Composition and Diversity in Response to Enterotoxigenic Escherichia coli Infection and Colistin Treatment in Weaned Piglets

“…However, Li et al, recently reported that the human intestinal bacterial community was significantly disturbed by the combinatorial colistin and amoxicillin (a broad-spectrum beta-lactamase antimicrobial) exposure, illustrating that this combinatorial antibiotic exposure, which may have an impact on several different intestinal bacterial families, could lead to long-term effects on the bacterial diversity of a simulated human intestinal microbiota as well as an increase in the relative abundance of opportunistic pathogens within this microbiota [ 52 ]. Likewise, it was reported that the oral administration of broad-spectrum antimicrobials (e.g., amoxicillin, chlortetracycline) in clinically healthy pigs was associated with a significant alteration in the composition of the fecal microbiota of the treated animals [ 24 , 53 ].…”