Nutritional and Digestive Factors Affecting Health and Performance in Weaned Pigs

Publikation: Bog/antologi/afhandling/rapportPh.d.-afhandling

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In pig production, the majority of antibiotics is used to treat gastrointestinal disorders causing diarrhoea during the weaning period. The risk of transmitting antibiotic resistant bacteria from animals to humans has increased the demand for lowering antibiotic use in animals. Together with the ban of medical levels of zinc oxide from June 2022, pig farmers are challenged when it comes to treating diarrhoea and lowering the consumption of antibiotics. The overall objective of this thesis was to increase knowledge on strategies to reduce the consumption of antibiotics used for intestinal disorders during the weaning period.
This PhD comprised three experiments, which aimed to answer four research questions; 1) does weaning pigs’ protein digestibility increase over time after weaning? 2) Does threonine (Thr) supplementation above nutrient recommendation reduce the risk of diarrhoea on a commercial farm? 3) Can supplementation of Thr and/or tryptophan (Trp) above nutrient recommendation benefit parameters of gut health and appetite? 4) Is a high feed intake (FI) during the first 4 days after weaning beneficial for parameters of gut health and does it decrease the risk of diarrhoea?
Protein digestibility increased with time after weaning. During the first two weeks, the protein digestibility was very low compared to the digestibility coefficients used to formulate diets. A low protein digestibility results in increased flow of undigested nitrogen to the lower gastrointestinal tract and may contribute to the high probability of diarrhoea during the first two weeks post-weaning (PW). To answer the next two research questions, one experiment on a commercial farm and one at the experimental facility at AU Foulum were performed. Increasing Thr levels above the nutrient recommendation on a commercial farm did not result in reduced probability of diarrhoea between day 21 to 32 PW or had any positive effect on growth performance. Diarrhoea probability was also not affected by the supplementation of 20% extra Thr and/or Trp above nutrient recommendation from weaning until PW Day 28. Supplementation with Thr and Trp together did, however, stimulate neutral mucin production in the large intestine and pigs were treated less with antibiotics against diarrhoea. Overall, this suggests that supplementation with Thr and/or Trp above nutrient recommendation is not an effective strategy to lower diarrhoea during the weaning period. Contrary to expectation, a high versus a low FI during PW day 0 to 4 was not beneficial for diarrhoea probability or other gut health parameters, besides stimulation of acid mucin production in the small intestine. Pigs with a high FI level were found to have an increased probability of diarrhoea and increased number of days treated with antibiotics.
This PhD work concluded that protein digestibility increases with age, a high FI just after weaning increases the risk of diarrhoea, and supplementation of Thr and/or Trp above nutrient recommendation was not able to reduce the probability of diarrhoea.
ForlagÅrhus Universitet
Antal sider138
StatusUdgivet - jun. 2023