Effect on Feeding Behaviour and Growing of Being a Dominant or Subordinate Growing Pig and Its Relationship with the Faecal Microbiota.

Pigs are a social species, and they establish hierarchies for better use of resources and to reduce conflicts. However, in pig production, the opportunities for growth can differ between dominant and subordinate animals. In the present study, a system was tested to perform a dominant versus subordinate test in growing pigs to investigate how the hierarchy affects feeding behaviour, growth, and gut microbiota assessed in faeces. Sixty-four animals housed in eight different pens were used, with four castrated males and four females in each one, weighing 18 kg at arrival and maintained during the whole growing period, until 140 kg. Three stool samples were obtained from the animals directly from the anus to avoid contamination of the faeces 58, 100, and 133 days after the start of the study to investigate the microbiota composition. The dominant animals had higher gains during the growing period than the subordinates. In addition, they were performing more visits to the feeder throughout the day. Differential abundance patterns were observed in five bacterial genera, with Oliverpabstia, Peptococcus, and Faecalbacterium being more abundant in dominant animals and Holdemanella and Acetitomaculum being overrepresented in subordinate ones. This microbial biomarker accurately classified dominant versus subordinate groups of samples with an AUC of 0.92.

Ultra-diluted complex additive in the diet reveals benefits in the intestinal tract of nursery-phase piglets.

This study aimed to assess an ultra-diluted (UD) complex, as a replacement for an antimicrobial growth promoter in diets, on growth performance, intestinal health, and inflammatory response of nursery piglets. The experiment lasted 37 days and involved 126 animals weaned at 21 ± 1.3 d, with an initial body weight of 5.62 ± 1.16 kg. Piglets were assigned to six dietary treatments in a randomized block design with seven replicates and three piglets per pen as experimental unit. The treatments were: positive control (PC)- basal diet + 120 mg/kg of chlorohydroxyquinoline; negative control (NC)- basal diet without additives; and NC containing 4.5; 6.0; 7.5 or 9.0 kg of UD additive/ton diet. Performance data were calculated, and daily diarrhea was observed. Blood samples were collected for hematological analysis. At the end of the experiment, one animal per pen was slaughtered for organ weighing, pH, and the collection of intestinal samples for histopathology. Feces and cecal contents were collected for microbiological and antibiogram analyses. There was no difference in the performance between the treatments. Throughout the study, UD levels were equal to those of PC for diarrhea occurrence. Higher levels of UD complex led to higher total leukocyte counts. The 4.5 treatment showed a reduction in total and thermotolerant Enterobacteriaceae populations in piglet feces and an increase in lactic acid bacteria compared to PC. All treatments resulted in fewer duodenal histopathological alterations than those in the NC group. The use of UD additives, especially at 4.5 kg/ton, is a good alternative to chlorohydroxyquinoline in piglet diets.