Effect on Gilt Behavior and Postures when Selected for Residual Feed Intake Selection in Response to a Lipopolysaccharide Challenge

The objective of this study was to determine low and high-RFI gilt sickness behavior when challenged with lipopolysaccharide (LPS). This work was conducted with seven low residual feed intake gilts (RFI) and eight high RFI gilts (63±4 kg BW) from the 8th generation of the ISU Yorkshire RFI selection lines. Gilts were challenged intramuscularly with 30 µg/kg BW Escherichia coli O5:B55 LPS at 1000±1 hour. Gilts were video recorded one day before the LPS challenge (baseline) and on the treatment day (LPS challenge). Video was analyzed for lying, sitting, standing, eating and drinking using a 1-minute scan sample at two time points on the baseline and treatment days; 1) 1000 to 1200 hour and 2) 1700 to 1800 hour. There were no line by treatment interactions for behaviors and postures in response to the LPS challenge (P ≥ 0.32). There were no RFI selection line differences in behavioral and postural responses to the LPS challenge (P ≥ 0.45). Regardless of the RFI selection line, after the LPS challenge gilts laid more (P \u3c 0.0001) and stood less (P \u3c 0.0001). However, there were no differences observed in the percent of time engaged in sitting, eating and drinking (P ≥ 0.16). Regardless of the RFI selection line, gilts laid more (P = 0.0004) and stood and ate less (P \u3c 0.0001) during the first (AM) compared to the second time point (PM). In conclusion, gilts from both RFI selection lines similarly expressed classical sickness behaviors and postures when challenged with LPS

Acute Systemic Inflammatory Response to Lipopolysaccharide Stimulation in Pigs Divergently Selected for Residual Feed Intake

Background: It is unclear whether improving feed efficiency by selection for low residual feed intake (RFI) compromises pigs’ immunocompetence. Here, we aimed at investigating whether pig lines divergently selected for RFI had different inflammatory responses to lipopolysaccharide (LPS) exposure, regarding to clinical presentations and transcriptomic changes in peripheral blood cells. Results: LPS injection induced acute systemic inflammation in both the low-RFI and high-RFI line (n = 8 per line). At 4 h post injection (hpi), the low-RFI line had a significantly lower (p= 0.0075) mean rectal temperature compared to the high-RFI line. However, no significant differences in complete blood count or levels of several plasma cytokines were detected between the two lines. Profiling blood transcriptomes at 0, 2, 6, and 24 hpi by RNA-sequencing revealed that LPS induced dramatic transcriptional changes, with 6296 genes differentially expressed at at least one time point post injection relative to baseline in at least one line (n =4 per line) (|log2(fold change)| ≥ log2(1.2); q \u3c 0.05). Furthermore, applying the same cutoffs, we detected 334 genes differentially expressed between the two lines at at least one time point, including 33 genes differentially expressed between the two lines at baseline. But no significant line-by-time interaction effects were detected. Genes involved in protein translation, defense response, immune response, and signaling were enriched in different co-expression clusters of genes responsive to LPS stimulation. The two lines were largely similar in their peripheral blood transcriptomic responses to LPS stimulation at the pathway level, although the low-RFI line had a slightly lower level of inflammatory response than the high-RFI line from 2 to 6 hpi and a slightly higher level of inflammatory response than the high-RFI line at 24 hpi. Conclusions: The pig lines divergently selected for RFI had a largely similar response to LPS stimulation. However, the low-RFI line had a relatively lower-level, but longer-lasting, inflammatory response compared to the high-RFI line. Our results suggest selection for feed efficient pigs does not significantly compromise a pig’sacute systemic inflammatory response to LPS, although slight differences in intensity and duration may occur

Multi-Farm Analyses Indicate a Novel Boar Pheromone Improves Sow Reproductive Performance

The objective of this study was to examine the effectiveness of a novel 3-molecule boar pheromone (BOARBETTER®, BB,) to improve sow reproductive performance (breeding, conception, farrowing rates, pigs born alive, stillborn, mummies and total born). Data from 12 commercial farm sites were used to evaluate the effectiveness of BB. Each farm was used as the experimental unit in the meta-analyses. Individual sows records were collected, merged and analyzed in overall analyses. Relative to CON, BB increased the number of total born pigs per litter (13.81 ± 0.11 vs. 14.30 ± 0.11 pigs/litter, respectively; p < 0.01) and the number of pigs born alive (12.76 ± 0.14 vs. 13.13 ± 0.14 pigs/litter, respectively; p < 0.05). In the merged dataset analyses, the parity by treatment interaction was significant for total pigs and pigs born alive per litter (p < 0.01). In parities one through three, treatment with BB increased total pigs born by 0.88 per litter, and pigs born alive per litter by 0.73 pigs per litter (p < 0.05). However, BB had no effect on these parameters in sows from parities four through six. BOARBETTER® increased reproductive success, is cost effective, safe, and can meaningfully improve sow reproductive success and performance

Preliminary Study: Depriving Piglets of Maternal Feces for the First Seven Days Post-Partum Changes Piglet Physiology and Performance before and after Weaning

Coprophagy has been described in piglets although its importance has not been fully assessed. The aim of this study was to evaluate how deprivation of maternal feces influenced piglet physiology, behavior, and performance. Eight litters were randomly assigned to one of two treatments. Control (CON) litters had access to maternal feces while deprived (DEP) litters were deprived of maternal feces for the first 7 d post-partum. Piglet behavior was quantified for 24 h at 7 d of age. Blood samples were collected from one male and female from each litter at 0, 7, and 21 d for hematological analyses, and post-weaning performance was assessed until 123 d post-weaning. No treatment effects were observed on piglet behavior. DEP piglets had 25% lower leukocyte counts (p < 0.01). Relative to DEP litters, CON litters had increased post-weaning feed intake (0.998 vs 0.901 kg/d; p = 0.02) and weight gain (0.536 vs 0.483 kg/d; p < 0.01). At 123 d post-weaning, CON pigs were 9.3 ± 2.3 kg heavier than treatment pigs (p < 0.01). These results suggest that access to maternal feces improves immunocompetence and growth performance. Further studies are needed to explore the physiological mechanisms through which maternal feces improve growth performance, including nutritional and microbial factors, or the presence of maternal semiochemicals

Effect on Gilt Behavior and Postures when Selected for Residual Feed Intake Selection in Response to a Lipopolysaccharide Challenge

The objective of this study was to determine low and high-RFI gilt sickness behavior when challenged with lipopolysaccharide (LPS). This work was conducted with seven low residual feed intake gilts (RFI) and eight high RFI gilts (63±4 kg BW) from the 8th generation of the ISU Yorkshire RFI selection lines. Gilts were challenged intramuscularly with 30 µg/kg BW Escherichia coli O5:B55 LPS at 1000±1 hour. Gilts were video recorded one day before the LPS challenge (baseline) and on the treatment day (LPS challenge). Video was analyzed for lying, sitting, standing, eating and drinking using a 1-minute scan sample at two time points on the baseline and treatment days; 1) 1000 to 1200 hour and 2) 1700 to 1800 hour. There were no line by treatment interactions for behaviors and postures in response to the LPS challenge (P ≥ 0.32). There were no RFI selection line differences in behavioral and postural responses to the LPS challenge (P ≥ 0.45). Regardless of the RFI selection line, after the LPS challenge gilts laid more (P < 0.0001) and stood less (P < 0.0001). However, there were no differences observed in the percent of time engaged in sitting, eating and drinking (P ≥ 0.16). Regardless of the RFI selection line, gilts laid more (P = 0.0004) and stood and ate less (P < 0.0001) during the first (AM) compared to the second time point (PM). In conclusion, gilts from both RFI selection lines similarly expressed classical sickness behaviors and postures when challenged with LPS.</p