INVESTIGATION OF ACUTE STRESS IMPACT ON NURSERY PIG GASTROINTESTINAL FUNCTION AND ABILITY OF BIOACTIVE COMPONENTS OF GARLIC TO MITIGATE STRESS-INDUCED PHYSIOLOGICAL CHANGES

Experiments were conducted to determine the effect of post-weaning feed and water deprivation on nursery pig growth performance, gastrointestinal function, and ability of garlic-derived diallyl disulfide (DADS) and diallyl trisulfide (DATS) to mitigate deprivation-induced effects. For the first experiment, the effects of a 24-h post-weaning feed, water, or feed + water deprivation event on nursery pig growth and intestinal characteristics were determined. Water deprivation more severely impacted nursery pig growth and intestinal measurements compared to feed deprivation. The water deprivation event resulted in an increase in serum stress markers and altered intestinal morphology and tight junction gene expression during the first week post-weaning. Furthermore, the acute post-weaning deprivation event impacted growth performance throughout the nursery period and resulted in pigs 0.57 kg lighter at 28 d post-weaning. A second experiment examined the interaction between a 24-h post-weaning feed + water deprivation event and a subsequent cyclic heat stress event. The results showed that the feed + water deprivation event reduced growth performance, increased serum stress markers, decreased ileal morphology, and altered intestinal tight junction gene expression similar to the first experiment. Growth performance and intestinal tight junction gene expression were decreased during the heat stress period. Growth performance results showed a stress event interaction in which nursery pig performance was poorest in pigs exposed to both stress events. Next, an in-vitro experiment was conducted to determine if garlic-derived DADS + DATS could mitigate hydrogen peroxide- and LPS-induced oxidant and endotoxin stress, respectively, in porcine epithelial (IPEC-J2) cells. Results showed that the garlic-derived compounds could mitigate oxidative stress by increasing superoxide dismutase and catalase activity. Furthermore, DADS + DATS were immune modulatory and augmented the LPS-induced increase in interleukin 8 (IL-8) secretion. Following the in-vitro evaluation, two in-vivo pilot trials were conducted to identify the optimal dosage of DADS + DATS and to evaluate the effect of graded doses of DADS + DATS on nursery pig and broiler chicken performance and gastrointestinal function. Garlic-derived DADS + DATS were supplemented to pigs and chickens by daily oral gavage for a period of 6 d. The oral gavage of DATS + DATS did not impact nursery pig growth performance, although ileal villus height was increased. Furthermore, there was a linear increase in IL-8 and a decrease in zonula occludens 1 (ZO-1) ileal gene expression due to oral DADS + DATS administration. The optimal dosage of DATS + DATS to maximize ileal villus height was determined to be 1.7 mg per kg BW. For the broiler chicken trial, DADS + DATS supplementation by oral gavage improved BW gain, ileal morphology,

Name thesis:degree_name

Doctor of Philosophy (PhD)

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Animal Science

Year

2015

Author dc:creator

• Horn, Nathan Lane

Contributors dc:contributor

• Olayiwola Adeola
• Kolapo Ajuwon
• Frank Ruch
• Susan Eicher

Repository record dc:identifier

https://docs.lib.purdue.edu/open_access_dissertations/1116

OAI identifier oai:identifier

oai:docs.lib.purdue.edu:open_access_dissertations-2332