Effect of lipopolysaccharide-induced immune stimulation and maternal fish oil and microalgae supplementation during late pregnancy on nursery pig hypothalamic-pituitary-adrenal function1.

The present study used Escherichia coli lipopolysaccharide (LPS) to investigate whether maternal immune challenge during late gestation altered programming of the offspring hypothalamus and hypothalamic-pituitary-adrenal axis (HPAA). In addition, interactions of maternal diet, supplementation with fish oil (FO) or microalgae (AL), and complex vs. simple weaning diets were investigated. Briefly, Landrace × Yorkshire sows (N = 48) were randomly assigned to diets supplemented with FO, AL, or a standard gestation control diet (CON) from day 75 of gestation (gd 75) until parturition. On gd 112, half the sows from each dietary treatment were immune challenged with LPS (10 µg/kg BW) or saline as a control. At 21 d postpartum, the offspring were weaned, and half the animals from each maternal treatment were allocated to either a complex or simple weaning diet. At 28 d postpartum, the offspring's hourly fever and 2-h cortisol responses to LPS immune challenge (40 µg/kg BW) were measured to assess hypothalamus and HPAA function. Results indicated that the maternal temperature of sows on the FO diet returned to baseline levels faster than sows on the AL and CON diets after LPS immune challenge (P < 0.05). In contrast, there was no difference in the maternal cortisol response across the dietary treatments (P > 0.10). Regardless of the dietary treatments, the maternal LPS immune challenge induced a greater cortisol response in male offspring (P = 0.05) and a greater fever response in female offspring (P = 0.03) when they were LPS immune challenged post-weaning. Male offspring from LPS-immune-challenged sows fed the FO and AL diets had a greater fever response than male offspring from the maternal CON diet group (P ≤ 0.05). Last, no effect of the complex or simple weaning diets was observed for the nursery pig cortisol or fever responses to LPS immune challenge. In conclusion, LPS immune challenge during late pregnancy altered responsiveness of the offspring hypothalamus and HPAA to this same microbial stressor, and a sex-specific response was influenced by maternal dietary supplementation with FO and AL.

An economic evaluation of intervention strategies for Porcine Epidemic Diarrhea (PED).

The economic losses of Porcine Epidemic Diarrhea (PED) and the net benefits of strategies to control the virus are calculated for individual farrow-to-finish herds. A production simulation model that estimates the number of pigs by population cohorts on a weekly basis for a farrow-to-finish farm depending on production parameters is simulated under normal operating conditions and then with an outbreak of PED. The estimated annual costs of a PED outbreak with the closure of the breeding herd as the only intervention is approximately $300,000 for a 700-sow farrow-to-finishing herd. The net returns per sow (hog) fall from $255 ($11.54) to a loss of $174 ($10.68). These losses can be significantly reduced with any of the 16 intervention strategies considered in this study. The most profitable strategy involving front loading of gilts with average feedback of infected material to improve herd immunity, intensive biosecurity protocols and no vaccination costs $27,000 to implement but reduces losses by 10 times this amount. Even the implementation of the least comprehensive strategy, which involves back-loading gilts after the herd reopens and an average feedback practice at a cost of $1000 reduces the losses caused by a PED outbreak by $130,000. Front-loading gilts in combination with herd closure is more cost-effective than back-loading. Despite the extra spending on intensive biosecurity protocols, the overall loss reductions achieved by the intensive biosecurity effort can be significant. Vaccination is the least cost-effective of the intervention practices considered. Even with significant increases in cost or effectiveness in the practices, intervention is justified across all strategies. The spreadsheet model of a farrow-finish hog farm developed in this study can be used to examine changes to the production parameters or to consider other swine disease outbreaks.

Evaluation of alginate-whey protein microcapsules for intestinal delivery of lipophilic compounds in pigs.

BACKGROUND: In animal care and management, there is an increasing demand for convenient methods of oral delivery of bioactive compounds to specific segments of an animal's gastrointestinal tract. The objective of this study was to test the suitability of microcapsules made with alginate and whey proteins of two different sizes (250 and 800 µm; containing 72 and 76 g kg(-1) of carvacrol respectively) for intestinal delivery of carvacrol in pigs. RESULTS: Encapsulated carvacrol was completely released from the microcapsules after 5 h incubation in simulated intestinal fluids or 6 h in (ex vivo) ileal digesta, whereas release in simulated gastric fluid was minimal. Tests with growing pigs showed over 95% of unencapsulated carvacrol was absorbed or metabolized in the stomach and the duodenum. Encapsulation effectively minimized carvacrol absorption in the stomach (P < 0.05), and increased carvacrol recovery in the small intestine (P < 0.05). Encapsulated carvacrol was completely released from both small and large size capsules within the gastrointestinal tract of pigs. Larger size microcapsules showed a slower in vitro release and greater in vivo recovery of carvacrol in the small intestine (P < 0.05) than the smaller ones. CONCLUSION: This study indicates alginate-whey protein microencapsulation is a feasible approach for targeted oral delivery of hydrophobic compounds to pig intestines; increasing capsule size increased delivery of carvacrol to the end of the small intestine. © 2015 Her Majesty the Queen in Right of Canada Journal of the Science of Food and Agriculture © 2015 Society of Chemical Industry.

Alterations in ileal mucosa bacteria related to diet complexity and growth performance in young pigs.

BACKGROUND: Evaluation of the prolonged impact of weaning diet on ileal mucosa bacteria and during periods of reduced and improved growth was conducted using 454 pyrosequencing. METHODOLOGY/PRINCIPAL FINDINGS: Weaned pigs were fed HIGH or LOW complexity diets, with or without antibiotics, for 6 weeks, followed by a common grower diet. Pigs were killed at 2 (n = 4 or 5) and 8 (n = 6) weeks post-weaning (periods of reduced and improved growth, respectively). Mucosal bacteria were removed; DNA was extracted and amplified using the V1-V3 region of the 16S rRNA gene. Mucosal bacteria clustered more closely by week post-weaning than diet but 44% of bacterial species did not change from week 2 to 8. There was no effect of diet complexity or antibiotic inclusion on indices of bacterial diversity. Firmicutes made up 91 and 96% of total reads at week 2 and 8, respectively. The proportion of Clostridium paraputrificum increased (P = 0.003) from week 2 to 8 in pigs fed LOW but didn't change in pigs fed HIGH; whereas Clostridium leptum decreased (P = 0.02) from week 2 to 8 in pigs fed LOW but didn't change in pigs fed HIGH. The proportion of Sarcina genus was 3-fold higher in pigs fed A+ compared to A- at week 2 and 5-fold higher at week 8 despite the lack of in-feed antibiotics at that time. CONCLUSIONS/SIGNIFICANCE: Shifts in mucosal bacteria populations may be related to dietary induced changes in growth performance during reduced and improved growth but further studies are required to confirm causative relationship. Weaning diet results in species specific prolonged alterations in mucosal bacteria, particularly where high levels of in-feed antibiotics are used. A considerable portion of ileal mucosal bacteria colonize early and remain stable over time despite changes in diet.

Epidermal growth factor-expressing Lactococcus lactis enhances intestinal development of early-weaned pigs.

Stress and incomplete gastrointestinal development in early-weaned piglets represent significant challenges in commercial swine farming. Orally ingested recombinant epidermal growth factor (EGF) has been shown to remain biologically active in the gastrointestinal tract as well as stimulate intestinal development, reducing the incidence of pathogen infection and diarrhea. We have previously shown that the food-grade bacterium Lactococcus lactis can be genetically altered to express biologically active EGF when fed to early-weaned mice. In this study, we assigned 8 pigs to each of 4 groups that were given EGF-expressing L. lactis (EGF-LL), empty vector-expressing L. lactis (EV-LL), recombinant human EGF, or unsupplemented bacterial media, all of which were delivered as 50-mL i.g. doses twice per day. All pigs were killed after 14 d to examine intestinal morphology. Pigs in the EGF-LL group had greater jejunal and duodenal villus heights (P < 0.0001) and intestinal length (P = 0.049) than pigs in the control group. Immunohistochemistry with antibodies against proliferating cell nuclear antigen (PCNA) revealed that the proliferation of intestinal cells was significantly greater in the EGF-LL group than in the control group. PCNA expression and intestinal length also were greater in the EV-LL group, which received L. lactis that did not express EGF, than in the control group (P = 0.049), further supporting the use of naturally occurring intestinal microbes as desirable vectors for recombinant protein delivery. Our data demonstrates the feasibility of delivering a growth factor using common probiotic bacteria to farm animals for commercial practice.

Previous feeding level influences plateau heat production following a 24 h fast in growing pigs.

Factorial approaches to estimate energy requirements of growing pigs require estimation of maintenance energy requirements. Heat production (HP) during fasting (FHP) may provide an estimate of maintenance energy requirements. Six barrows were used to determine effects of feeding level on components of HP, including extrapolated plateau HP following a 24 h fast (FHPp). Based on a cross-over design, each pig was exposed to three feeding levels (1.55, 2.05 and 2.54 MJ metabolisable energy/kg body weight (BW)(0.60) per d) between 30 and 90 kg BW. Following a 14 d adaptation period, HP was estimated using indirect calorimetry on pigs housed individually. Dynamics of HP were recorded in pigs for 5 d during the fed state and during a subsequent 24 h fast. Metabolisable energy intake was partitioned between thermal effect of feeding (HPf), activity HP (HPa), FHPp and energy retention. Feeding level influenced (P<0.05) total HP during the fed state, HPf and activity-free FHPp (609, 644 and 729 (SE 31) kJ/kg BW(0.60) per d for low, medium and high ME intakes, respectively). The value of FHPp when expressed per kg BW(0.60) did not differ (P=0.34) between the three subsequent experimental periods. Feeding level did not (P=0.75) influence HPa. Regression of total HP during the fed state to zero metabolisable energy intake yielded a value of 489 (SE 69) kJ/kg BW(0.60) per d, which is a lower estimate of maintenance energy requirement than FHPp. Duration of adaptation of pigs to changes in feeding level and calculation methods should be considered when measuring or estimating FHPp, maintenance energy requirements and diet net energy content.

Observational study of factors associated with nursery pig performance.

The objective of this study was to determine the association between body weight of pigs at 7 wk of age, specific management factors, and previous body weight. Among 3736 pigs from 8 commercial farms, greater 7-wk weight was associated with greater birth weight (P = 0.001), greater weaning weight (P = 0.001), and earlier age at weaning (P = 0.001). Farms with the earliest average weaning age had the highest health status. Farms with later weaning ages tended to use nurse sows for light-weight pigs. Pigs from farms using all-in/all-out management in the nursery had greater 7-wk weights (P = 0.01). The total mortality and culling rate during the nursery phase (weaning to approximately 7 wk of age) was 6.8%. Higher losses were observed among pigs with low weaning weights (< 4.1 kg) compared with those with higher weaning weights. More of the variation due to 7-wk weight was due to individual sow rather than to farm of origin.