Fixation is the first step towards preservation of tissues and can impact downstream histological applications. Historically, formalin has been the fixative of choice in both research and clinical settings due to cost, accessibility, and broad applicability. Here, we describe a method for collection of porcine colon, and compare the usage of Carnoy’s solution (CS) to a 10% neutral buffered formalin (NBF) in tissue fixation. Consecutive colon samples were collected from 24 four-wk-old piglets and fixed in CS for 45 min or NBF for 24 h. We measured the thickness of the inner mucus layer using Alcian Blue stain and found thicker inner mucus layers in porcine colons fixed with CS as compared to NBF (P < 0.0001). Carnoy’s solution-fixed colon exhibited greater bacterial cell counts than NBF-fixed colon (P < 0.0022) after labeling with an eubacterial probe in fluorescent in situ hybridization (FISH). No difference was observed between the mucosal height (P = 0.42) and number of goblet cells (P = 0.66) between the 2 fixatives. From this, we concluded CS is more suitable than NBF for the preservation of the mucus layer and the associated mucosal bacteria in the porcine colon without compromising on overall tissue morphology. This study provides a useful sampling and fixation methodology for histology studies in the porcine gastrointestinal tract, and may be beneficial to microbiota, pathology, and nutrition studies.

Post-weaning enteropathies in swine caused by pathogenic E. coli, such as post-weaning diarrhea (PWD) or edema disease (ED), remain a significant problem for the swine industry. Reduction in the use of antibiotics over concerns of antibiotic resistance and public health concerns, necessitate the evaluation of effective antibiotic alternatives to prevent significant loss of livestock and/or reductions in swine growth performance. For this purpose, an appropriate piglet model of pathogenic E. coli enteropathy is required. In this study, we attempted to induce clinical signs of post-weaning disease in a piglet model using a one-time acute or lower daily chronic dose of a pathogenic E. coli strain containing genes for both heat stable and labile toxins, as well as Shiga toxin. The induced disease state was monitored by determining fecal shedding and colonization of the challenge strain, animal growth performance, cytokine levels, fecal calprotectin, histology, fecal metabolomics, and fecal microbiome shifts. The most informative analyses were colonization and shedding of the pathogen, serum cytokines, metabolomics, and targeted metagenomics to determine dysbiosis. Histopathological changes of the gastrointestinal (GI) tract and tight junction leakage as measured by fecal calprotectin concentrations were not observed. Chronic dosing was similar to the acute regimen suggesting that a high dose of pathogen, as used in many studies, may not be necessary. The piglet disease model presented here can be used to evaluate alternative PWD treatment options.

Two experiments were conducted to evaluate the effects of including liquid lactose (LL) and molasses (M) in swine diets on pellet quality and pig performance. In experiment 1, a total of 194 nursery pigs (DNA 241 × 600, initially 6.7 ± 0.4 kg at 27 d of age) were used in a 33-d experiment evaluating the effects of LL (SweetLac 63; Westway Feed Products, Tomball, TX) or cane molasses on nursery pig performance and pellet quality. Pelleted experimental diets were fed from d 0 to 21, and a common pelleted diet fed from d 21 to 33. Dietary treatments consisted of a control diet containing 19.1% total sugars from whey powder and whey permeate and experimental diets with a percentage of whey permeate replaced by either 5% or 10% LL or 9.4% cane molasses (5 LL, 10 LL, and 9.4 M, respectively). Hot pellet temperature and production rate decreased (P < 0.05) from the control to 9.4 M treatments with 5 LL and 10 LL having intermediate effects. Pellet durability index (PDI) increased (P < 0.05) in 5 LL, 10 LL, and 9.4 M, respectively. From d 0 to 7, pigs fed the 10 LL and 9.4 M treatment had the best G:F followed by the control and 5 LL treatments. From d 0 to 21, ADFI had a marginally significant improvement (P < 0.10) in pigs fed up to 10 LL in the diet. Fecal consistency scores at d 7 were also firmer (P < 0.05) in pigs fed 9.4 M compared with pigs fed the control or 5 LL treatments with pigs fed the 10 LL treatment being intermediate. There was no evidence for differences in fecal consistency scores for d 14. In experiment 2, a total of 289 finishing pigs (DNA 241 × 600; initially 53.5 ± 0.5 kg BW) were used in a 53-d experiment evaluating the effects of LL on pellet quality and finishing pig performance. Experimental diets were fed in pelleted form from d 0 to 53 divided into three phases. Dietary treatments were a corn-soybean meal control diet with 0%, 2.5%, 5%, and 7.5% LL added in the place of corn. PDI improved (linear, P < 0.01) with increasing inclusion of LL. There were no differences in ADG, ADFI, final BW, or carcass characteristics. Pigs fed diets with increasing levels of LL tended to have improved (quadratic, P = 0.070) G:F.

Post-weaning enteropathies in swine caused by pathogenic E. coli, such as post-weaning diarrhea (PWD) or edema disease (ED), remain a significant problem for the swine industry. Reduction in the use of antibiotics over concerns of antibiotic resistance and public health concerns, necessitate the evaluation of effective antibiotic alternatives to prevent significant loss of livestock and/or reductions in swine growth performance. For this purpose, an appropriate piglet model of enterotoxigenic E. coli enteropathy is required. In this study, we attempted to induce clinical signs of post-weaning disease in a piglet model using a one-time acute or lower daily chronic dose of a Shiga toxin–producing and enterotoxigenic E. coli strain. The induced disease state was monitored by determining fecal shedding and colonization of the challenge strain, animal growth performance, cytokine levels, fecal calprotectin, histology, fecal metabolomics, and fecal microbiome shifts. The most informative analyses were colonization and shedding of the pathogen, serum cytokines, metabolomics, and targeted metagenomics to determine dysbiosis. Histopathological changes of the gastrointestinal (GI) tract and tight junction leakage as measured by fecal calprotectin concentrations were not observed. Chronic dosing was similar to the acute regimen suggesting that a high dose of pathogen, as used in many studies, may not be necessary. The piglet disease model presented here can be used to evaluate alternative PWD treatment options. Furthermore, this relatively mild disease model presented here may be informative for modeling human chronic gastrointestinal diseases, such as inflammatory bowel disease, which otherwise require invasive procedures for study.

thank you for providing me the opportunity to continue my education, providing support and challenging me. To Dr. Wickersham, thank you for adopting me as one of your graduate students and for inviting me to spend holidays with your family.To Dr. Leslie Frenzel, Del Rio would not have been as entertaining without you, your advice and knowledge were tremendous. To Mike Penn, I mostly drove you crazy out at the farm but I know that you loved it.To my fellow graduate students, thank you for making Texas feel like home, I am better for knowing all of you. I look forward to seeing what life has in store for each of you and hope that one day our paths will cross again. The Swine Nutrition and Production (SNaP) Team -Sarah, Logan and Lily -thank you for all of the laughs and support in good and challenging times. You are all rock stars for helping my projects run smoothly. Jessica, Emily, and Amelia, thanks for fielding all of my questions, being listening ears, great roommates (pseudo-roommates) and friends.I am thankful to have had many mentors thus far in my life and for each I am grateful. My achievements are a testament to you and the guidance and wisdom you have shared. To Coach Ben Williamson, thank you for encouraging me to undertake this graduate school journey and believing in me when I had doubts. To my friends that v I consider family, while we are spread from coast to coast pursuing our dreams, please know that I think of you often and appreciate your love and support. Thank goodness for modern technology that we are able to remain so close when we live so far. To my family, they say you cannot pick your family but I would choose all of you, every time.I truly hit the family jackpot. Thank you for supporting all of my endeavors and cultivating my passion for agriculture. To my grandmothers and grandfather, I was only given you for a chapter of my life but your memory still lives in me every day. I hope I am making you proud. To Mom and Dad, my pillars, your love and support are unmatched. Dad, I have never met anyone that works harder than you, you are my inspiration to never give up and to figure it out when things get tough. You may say that "It's all about the money" but you do it all for your family and for others. Mom, you are so self-sacrificing for my happiness and the best cheerleader around. All that I am and hope to be, I owe to my mother. Above all, I thank God for giving me the courage to pursue my dreams, wherever they may lead.