CategorySwine Health - General Disease
Date Full Report Received04/01/2014
Date Abstract Report Received04/01/2014
Funded ByNational Pork Board
In the last 10 years, Clostridium difficile has been implicated as a major cause of neonatal diarrhea in pigs. C. difficile infection (CDI) affects piglets ranging in age from 1-7 days. Clinical signs of CDI include diarrhea, abdominal distention and scrotal edema with most of the pathology being attributed to toxin production by this bacteria (Toxin A and B). Currently there are no commercial vaccines against C. difficile and the use of prophylactic antibiotics has been unsatisfactory and unrewarding for swine producers. Clostridium difficile infection is currently considered one of the most common causes of nosocomial diarrhea in humans. Therefore, we hypothesize that early oral administration of probiotics to pigs will control disease after experimental infection with C. difficile. An economical, safe, and simplistic therapy to control CDI and its subclinical incidence could be very beneficial to the swine industry.
Four replicates of the experimental design were conducted involving a total of 150 new born, caesarian derived piglets. Each experiment (replicate) divided piglets into 6 different study groups. GROUP 1 negative control, GROUP 2 piglets only received non-toxigenic C. difficile strain, GROPU 3 piglets received only probiotic yogurt, GROUP 4 positive control (challenged with toxigenic C. difficile strain), GROUP 5 animals received the probiotic non-toxigenic C. difficile strain and then challenged with the toxigenic C. difficile strain, GROUP 6 received probiotic yogurt and then challenge with the toxigenic C. difficile strain. Piglets were individually housed with non-challenged piglets (Groups 1 -3) being house in separate airspace than challenged piglets (Groups 4-6). The challenge isolate originated from a field case of neonatal diarrhea in 3-6 day-old piglets with high levels of toxin detected. Piglets were fed a set amount of milk replacer via gastric intubation three times daily. All pigs were humanely euthanized 72 hours post-challenge. The experimental protocol was approved by the Iowa State University Institutional Animal Care and Use Committee.
At necropsy, gross observations at necropsy included 1) body condition, 2) dehydration status, 3) perineal fecal staining, 5) consistency of colonic contents, 6) mesocolonic edema, and the presence of 7) visible colonic luminal necrosis and were scored independently in a blinded fashion as previously described. Necropsies, clinical sign scores and gross lesion scores were completed by the same two individuals for all experiments. Fresh and formalin fixed tissues including ileum, jejunum, descending colon, cecum, and a cross section of spiral colon were collected. All tissues were submitted for histopathologic examination by a veterinary pathologist that was blinded to animal group designation. Rectal swabs collected prior to inoculation and pooled colon and cecum contents collected at necropsy were assayed for C. difficile toxins using a commercially available toxin ELISA kit providing a semi quantitatively measure of the amounts of toxin from 0 (no toxin detection) to 4+ (marked toxin detection) as indicated by the manufacturer.
For statistical analysis, three categories of scores were compared: 1) clinical signs, 2) ELISA results and mesocolonic edema, and 3) microscopic lesions. Clinical signs scores were created by summing scores for body condition, hydration status, and perineum staining. Microscopic lesion score was the sum of scores for all histopathology categories as previously described.