Oral inoculation with Salmonella enterica serovar Typhimurium or Choleraesuis promotes divergent responses in the somatotropic growth axis of swine1

Abstract

Enteric disease and immune challenge are processes that have detrimental effects on the growth performance of young swine. The current study tested the hypothesis that salmonella-induced enteric disease would perturb the endocrine growth axis in a serovar-dependent fashion. Specifically, we evaluated the effects of Salmonella enterica serovar Typhimurium (Typhimurium) and serovar Choleraesuis (Choleraesuis) on critical regulatory components of growth in young swine. Weaned pigs were housed 2 per pen with ad libitum access to feed and water in a 14-d experiment. Pigs were then repeatedly fed 10 8 cfu of either Choleraesuis or Typhimurium in dough balls, with control pigs receiving dough without bacteria. Bacteria were refed twice weekly. Rectal temperatures were monitored daily from d 0 to 7 and ADFI was measured through d 14. Pigs were weighed and samples of serum were obtained for circulating IGF-I on d 0, 7, and 14. At the conclusion of the study, samples of semitendinosus muscle and liver were obtained and subsequently assayed for IGF-I, IGFBP-3, and IGFBP-5 mRNA. Rectal temperatures were elevated in pigs given Choleraesuis from d 2 through 7 (P < 0.05) when compared with control pigs and pigs fed Typhimurium. Pigs receiving Choleraesuis had a substantially decreased feed intake on d 2, 3, 4, 7, 8, 9, and 10 (P < 0.01), with a trend for a reduction on d 5 (P = 0.08), and they experienced an approximately 25% reduction in BW compared with control pigs and pigs given Typhimurium by the conclusion of the study. Pigs given Choleraesuis also experienced marked reductions in circulating IGF-I on d 7 (P < 0.01 vs. control and Typhimurium), with reductions of lesser magnitude on d 14 (P = 0.07 vs. control and P < 0.05 vs. Typhimurium). Inoculation tended to affect liver IGFBP-3 mRNA (P = 0.08), for which expression tended to be elevated in pigs given Typhimurium and Choleraesuis. In contrast, IGFBP-3 mRNA relative abundance was increased (P < 0.03) in pigs given Typhimurium compared with control pigs. Muscle IGF-I mRNA was reduced in pigs given Choleraesuis compared with control pigs and pigs given Typhimurium (P < 0.05). Treatment tended to affect muscle IGFBP-3 mRNA (P = 0.10). Oral inoculation of growing pigs with Choleraesuis disrupted feed intake and BW gain, and this was accompanied by decreases in circulating IGF-I and reduced muscle expression of mRNA for IGF-I and IGFBP-3.

A Simple Assay to Assess Salmonella Typhimurium Impact on Performance and Immune Status of Growing Pigs after Different Inoculation Doses

“…However, in this study the ST inoculation doses evaluated did not increase rectal temperature even with most animals excreting ST in the first week post-infection. The same results were reported by Davis et al [ 25 ] in younger pigs inoculated with 10 8 CFU of ST in a 14 days trial. The authors did not observe any differences in the rectal temperature of ST-inoculated pigs even when three doses were given at three different times.…”

“…The dose administration of 1 × 10 8 and 1.5 × 10 8 CFU in this study were chosen to more closely mimic the fecal–oral transmission of Salmonella organisms often found in intensive swine production conditions, as it was previously reported that growing–finishing phase pigs could shed high concentrations of ST in the environment (between 10 6 and 10 8 CFU/g of feces) [ 12 , 13 ]. Additionally, studies in which pigs were inoculated with doses between 10 6 and 10 7 showed the presence of mild infections or had no different outcomes from no-challenge animals [ 24 , 25 ]. Furthermore, when pigs were inoculated with higher doses of Salmonella Typhimurium (10 9 CFU) severe clinical responses and mortality were observed [ 18 ].…”

Metabolizable energy for piglets in the nursery phase submitted at activation of immune system

“…According to Shurson & Johnston (1998), the increase of tissue catabolism after activation of the immune system can be related to this process. Moreover, another likely explanation is the reduction of serum IGF-I (insulin-like growth factor type I), according to what was observed by Davis et al (2010). These authors inoculated orally Salmonella in pigs in the initial phase and observed reduction in the weight gain of the animals.…”

Insulin-like growth factor binding protein 5b of Trachinotus ovatus and its heparin-binding motif play a critical role in host antibacterial immune responses via NF-κB pathway

“…The top five tissues with the highest expression level were the liver, spleen, brain, gill, and head kidney. In humans, IGFBP5 was closely related to many diseases, such as colorectal cancer, chronic rhinosinusitis, sarcopenia, and so on ( 51 – 55 ), and pathogen infection induced a significantly higher expression of IGFBP5 in mammals—for example, IGFBP5 expression was significantly upregulated after Salmonella enterica stimulation in pigs ( 56 ). In our study, V. harveyi caused a significant induction of TroIGFBP5b in the liver, spleen, and head kidney.…”