Determination and prediction of the net energy content of wheat bran for pregnant sow.

Two experiments were conducted to determine net energy (NE) values of wheat bran ingredients and develop a prediction equation for NE of wheat bran. In each experiment, 12 multiparous pregnant sows were allocated to two 3 × 6 Youden squares with three consecutive periods and six diets in each square. The study consisted of six diets, including a corn-soybean meal basal diet and five diets formulated with 29.2% wheat bran. Each period lasted for 10 d, with 5 d allocated for adaptation and followed by 5 d for heat production measurement. Sows were provided feed at 604 kJ/kg BW0.75·d-1. On day 10, sows underwent fasting to measure fasting heat production. Results indicated that the inclusion of wheat bran in the diets significantly reduced digestibility of energy and nutrients in (p < 0.05). The average net energy (NE) content of wheat bran was determined to be 8.8 MJ/kg DM. A regress equation NE = 7.968 + 0.28 × CP + 0.607 × EE - 0.782 × ash - 0.05 × hemicellulose (R2 = 0.98, p < 0.01) was found to accurately predit the NE value when feeding pregnant sows with wheat bran-based diets. In conclusion, the net energy content of wheat bran fed to pregnant sows ranged from 7.24 to 10.67 MJ/kg DM and can be effectively estimated using proximate analysis methods.

Effects of soybean hulls and corn stalk on the performance, colostrum composition and faecal microflora of pregnant sows.

This study was conducted to investigate the effects of different supplementation levels of soybean hulls and corn stalk in high-fibre gestation diet on the performance, colostrum composition and faecal microbiota of sows. Forty first-farrowing Danish Landrace sows were randomly assigned to five dietary treatment groups. The control (CON, 3.15% crude fibre) group was fed a normal diet, and the treatment groups were soybean hulls low-fibre (SHL, 6.00% crude fibre) group, soybean hulls high-fibre (SHH, 8.00% crude fibre) group, corn stalk low-fibre (CSL, 6.00% crude fibre) group and corn stalk high-fibre (CSH, 8.00% crude fibre) group. The weaning weight of the litter and the average daily feed intake of the lactating sows in the SHL, SHH and CSH groups were higher than those in the CON group (p < 0.05). The immunoglobulin A and G levels of the colostrum in the SHL, SHH, CSL and CSH groups were higher than those in the CON group (p < 0.05), and the immunoglobulin M levels in the SHL, SHH and CSH groups were higher than those in the CON group (p < 0.05). The abundance of Proteobacteria at the phylum level in the CON group was higher than that in the CSL, CSH and SHH groups (p < 0.05). The abundance of Lactobacillaceae at the family level in the SHH and CSL groups were higher than that in the CON group (p < 0.05). The abundance of Lactobacillus at the genus level in the SHH and CSL groups were higher than that in the CON group (p < 0.05). In conclusion, SHH group had the best effect, and the optimal crude fibre level in the gestation diet of sows is 8%.

Safety and DIVA Capability of Novel Live Attenuated Classical Swine Fever Marker Vaccine Candidates in Pregnant Sows.

Classical Swine Fever (CSF), a highly contagious viral disease affecting pigs and wild boar, results in significant economic losses in the swine industry. In endemic regions, prophylactic vaccination and stamping-out strategies are used to control CSF outbreaks. However, sporadic outbreaks and persistent infections continue to be reported. Although the conventional attenuated CSF vaccines protect pigs against the disease, they do not allow for the differentiation of infected from vaccinated animals (DIVA), limiting their use as an eradication tool. In this study, three targeted attenuation strategies were employed to generate vaccine candidates based on the current prevalent CSFV group 2 strains GD18 and QZ07: a single deletion of H79 in Erns (QZ07-sdErnsH-KARD), double deletion of H79 and C171 in Erns (GD18-ddErnsHC-KARD and QZ07-ddErnsHC-KARD), and deletion of H79 in Erns combined with a 5-168 amino acids deletion of Npro (GD18-ddNpro-ErnsH-KARD). Additionally, a negative serological marker with four substitutions in a highly conserved epitope in E2 recognized by the monoclonal antibody 6B8 was introduced in each candidate for DIVA purposes. The safety of these four resulting vaccine candidates was evaluated in pregnant sows. Two candidates, GD18-ddErnsHC-KARD and QZ07-sdErnsH-KARD were found to be safe for pregnant sows and unlikely to cause vertical transmission. Both candidates also demonstrated potential to be used as DIVA vaccines, as was shown using a proprietary blocking ELISA based on the 6B8 monoclonal antibody. These results, together with our previous work, constitute a proof-of-concept for the rational design of CSF antigenically marked modified live virus vaccine candidates.

Effects of Italian ryegrass silage supplementation on feed intake and behavior of pregnant sows.

This study aimed to assess the behavior and stress status of pregnant sows following supplementation with Italian ryegrass silage (IRS) and the impact of feeding the IRS on feeding costs. Six sows with an initial body weight (BW) of 238.6 ± 5.9 kg were allotted to a 6 × 3 Latin square design with a 5-day acclimatization period followed by a 5-day data collection period. A commercial diet was replaced by IRS on a dry matter (DM) basis up to 0%, 9%, and 13% in the control treatment and the two test treatments, respectively. Apart from collecting data on daily feed intake and BW, urine was collected, and video footage was recorded for the last day of each treatment for analysis of urinary cortisol and behavior. There were no leftovers with all diets and nutrient uptake was unaffected (p > 0.05), while BW gain decreased (p < 0.05) to be a limited range from 1% to 3%, with increased inclusion of IRS. Both the behavior of sows and cortisol concentration were unaffected (p > 0.05). Furthermore, it was estimated that feeding 13% DM of IRS would reduce feed costs by 17%. IRS would be acceptable in replacing up to 13% of the commercial diet and cutting feeding costs.

Establish a Pregnant Sow-Neonate Model to Assess Maternal Immunity of a Candidate Influenza Vaccine.

While it is well appreciated that maternal immunity can provide neonatal protection, the contribution of maternal vaccination toward generating such immunity is not well characterized. In our previous work, we created a candidate influenza vaccine using our chimeric hemagglutinin (HA) construct, HA-129. The HA-129 was expressed as part of a whole-virus vaccine that was built on the A/swine/Texas/4199-2/98-H3N2 backbone to generate the recombinant virus TX98-129. The TX98-129 candidate vaccine has the ability to induce broadly protective immune responses against genetically diversified influenza viruses in both mice and nursery pigs. In the current study, we established a pregnant sow-neonate model to evaluate the maternal immunity induced by this candidate vaccine to protect pregnant sows and their neonatal piglets against influenza virus infection. In pregnant sows, the results consistently show that TX98-129 induced a robust immune response against the TX98-129 virus and the parental viruses that were used to construct HA-129. After challenge with a field strain of influenza A virus, a significant increase in antibody titers was observed in vaccinated sows at both 5 and 22 days post challenge (dpc). The challenge virus was detected at a low level in the nasal swab of only one vaccinated sow at 5 dpc. Evaluation of cytokine responses in blood and lung tissue showed that levels of IFN-α and IL-1ß were increased in the lung of vaccinated sows at 5 dpc, when compared to unvaccinated pigs. Further analysis of the T-cell subpopulation in PBMCs showed a higher ratio of IFN-γ-secreting CD4+CD8+ and CD8+ cytotoxic T cells in vaccinated sows at 22 dpc after stimulation with either challenge virus or vaccine virus. Finally, we used a neonatal challenge model to demonstrate that vaccine-induced maternal immunity can be passively transferred to newborn piglets. This was observed in the form of both increased antibody titers and deceased viral loads in neonates born from immunized sows. In summary, this study provides a swine model system to evaluate the impact of vaccination on maternal immunity and fetal/neonatal development.

Effects of Different Iron Supplements on Reproductive Performance and Antioxidant Capacity of Pregnant Sows as Well as Iron Content and Antioxidant Gene Expression in Newborn Piglets.

To improve the reproductive performance of sows and the iron nutrition of newborn piglets, we studied the effects of dietary iron on reproductive performance in pregnant sows as well as antioxidant capacity and the visceral iron content of sows and newborn piglets. Forty pregnant sows were divided into four groups, the iron deficiency group (Id group) was fed a basic diet while sows in the treatment groups were fed diets supplemented with 200 mg/kg lactoferrin (LF group), 0.8% heme-iron (Heme-Fe group), or 500 mg/kg iron-glycine complex (Fe-Gly group). The results indicated that (1) different sources of iron had no significant effect on litter size, live litter size, and litter weight of sows; (2) the three additives improved iron nutrition in newborn piglets, with LF and Heme-Fe having better improvement effects; and (3) the addition of different iron sources improved the level of serum antioxidant biochemical indexes of sows and newborn piglets, and it can have an effect on gene level, among which lactoferrin has the best effect. Thus, adding LF, Heme-iron, or Fe-Gly to the diet of sows during the second and third trimester of gestation can improve the antioxidant capacity of the sows. The supplementation of LF in pregnant sow diets can also improve the antioxidant capacity and the iron nutrition of newborn piglets, with better additive effects than in Heme-Fe and Fe-Gly.

Dietary Supplementation With Fine-Grinding Wheat Bran Improves Lipid Metabolism and Inflammatory Response via Modulating the Gut Microbiota Structure in Pregnant Sow.

This study investigated the effects of fine-grinding wheat bran on pregnant sow body condition, lipid metabolism, inflammatory response, and gut microbiota. In this study, wheat bran was crushed into three particle sizes. A total of 60 Landrace × Yorkshire second parity sows were allotted to two groups: CWB (a diet containing coarse wheat bran with particle size of 605 µm) and FWB (a diet containing fine wheat bran with particle size of 438 µm). Fine-grinding wheat bran had higher soluble dietary fiber concentration, swelling capacity, water-holding capacity, and fermentability than coarse wheat bran. Pregnant sows fed FWB throughout pregnancy had lower body weight and fat deposition than sows fed CWB. And the piglet body weight at birth of the FWB group was remarkably increased. Serum concentrations of lipids (triglycerides, total cholesterol, and free fatty acid), interleukin 6, leptin, and resistin were decreased on day 90 of pregnancy by fine wheat bran supplementation. Feeding FWB significantly decreased abundance of Firmicutes and dramatically increased the abundance of Bacteroidetes at phylum level. At genus level, the abundance of Terrisporobacter was decreased in FWB feeding sows, but the abundance of Parabacteroides was increased. Fecal total short-chain fatty acids, propionate, and butyrate contents were markedly increased in the FWB group. The results suggested that the physicochemical properties of finely ground wheat bran had been improved. Dietary supplementation with fine wheat bran changed the gut microbiota structure and enhanced the short-chain fatty acids level, which improved the maternal body condition, metabolic and inflammatory status, and reproductive performance in sows.

Effect of Maternal Catalase Supplementation on Reproductive Performance, Antioxidant Activity and Mineral Transport in Sows and Piglets.

This experiment was conducted to investigate the effects of maternal catalase (CAT) supplementation on reproductive performance, antioxidant enzyme activities, mineral transport, and mRNA expression of related genes in sows and offspring. A total of 40 pregnant sows at 95 days of gestation with similar parity (3−5 parities) and back-fat thickness were assigned randomly and equally into the control (CON) group (fed a basal diet) and CAT group (fed a basal diet supplemented with 660 mg/kg CAT; CAT activity, 280 U/g). The reproductive performance was recorded, and the placenta and blood samples of sows and neonatal piglets, as well as the jejunum and ileum samples from neonatal boars (eight replicates per group), were collected. Results showed that dietary supplementation with CAT significantly decreased the intrauterine growth restriction (IUGR) rate and increased the activity of serum CAT in neonatal piglets and umbilical cords (p < 0.05). In addition, CAT supplementation tended to improve total antioxidant capacity (T-AOC) levels in the maternal serum (p = 0.089) and umbilical cords of piglets (p = 0.051). The serum calcium (Ca), manganese (Mn), and zinc (Zn) of farrowing sows and Mn concentration in the umbilical cord, and serum Ca, magnesium (Mg), copper (Cu), and Mn of neonatal piglets were significantly increased (p < 0.05) in the CAT group. CAT supplementation downregulated mRNA expression of TRPV6 and CTR1 (p < 0.05), Cu/Zn SOD (p = 0.086) in the placenta and tended to increase the mRNA expression of the glutathione peroxidase 1 (GPX1) (p = 0.084), glutathione peroxidase 4 (GPX4) (p = 0.063), and CAT (p = 0.052) genes in the ileum of piglets. These results showed that the maternal CAT supplementation improved fetal growth by decreasing the IUGR rate, and modulated antioxidant activity, as well as mineral elements in the pregnant sows and their piglets.

Detection and Characterization of Viral Pathogens Associated with Reproductive Failure in Wild Boars in Central Italy.

Wild boar and domestic swine share several pathogens, including viruses responsible for reproductive failures, representing an important sanitary and economic risk for the swine industry. Among them, suid herpesvirus 1 (SuHV-1), porcine circovirus 2 (PCV2) and porcine parvovirus 1 (PPV1) are widely diffused in the wild boar population. Unfortunately, little is known about their pathogenetic mechanisms and impact on the reproductive parameters of wild animals. This study aims to investigate the presence of viruses responsible for reproductive failure in pregnant wild boar sows and their foetuses. The investigation was conducted on 46 pregnant wild boar and their foetuses by molecular analysis; a phylogenetic study was performed on the positive samples. All of the investigated pathogens were identified in sows, while only herpesvirus and circovirus were detected in the tissues of their foetuses. Phylogenetic analysis revealed that the viral sequences obtained from the positive wild boars were closely related to those previously identified in domestic swine belonging to the same study areas. The results suggest that SuHV-1 and PCV2 can infect wild boar foetuses, with a possible impact on wild boar reproductive performance. Moreover, our data highlight the importance of continuous monitoring of swine pathogens circulating in wild environments, so as to carry out adequate sanitary actions.

Immune Responses in Pregnant Sows Induced by Recombinant Lactobacillus johnsonii Expressing the COE Protein of Porcine Epidemic Diarrhea Virus Provide Protection for Piglets against PEDV Infection.

Porcine epidemic diarrhea (PED) induced by porcine epidemic diarrhea virus (PEDV) is an intestinal infectious disease in pigs that causes serious economic losses to the pig industry. To develop an effective oral vaccine against PEDV infection, we used a swine-origin Lactobacillus johnsonii (L. johnsonii) as an antigen delivery carrier. A recombinant strain pPG-T7g10-COE/L. johnsonii (L. johnsonii-COE) expressing COE protein (a neutralizing epitope of the viral spike protein) was generated. The immunomodulatory effect on dendritic cell in vitro and immunogenicity in pregnant sows was evaluated following oral administration. L. johnsonii-COE could activate monocyte-derived dendritic cell (MoDC) maturation and triggered cell immune responses. After oral vaccination with L. johnsonii-COE, levels of anti-PEDV-specific serum IgG, IgA, and IgM antibodies as well as mucosal secretory immunoglobulin A (SIgA) antibody were induced in pregnant sows. High levels of PEDV-specific SIgA and IgG antibodies were detected in the maternal milk, which provide effective protection for the piglets against PEDV infection. In summary, oral L. johnsonii-COE was able to efficiently activate anti-PEDV humoral and cellular immune responses, demonstrating potential as a vaccine for use in sows to provide protection of their piglets against PEDV.

Effects of time of feeding during gestation on sow's performance1.

The aim of this study was to investigate the effect of different feeding time regimes given similar energy intake per kilogram live BW0.75 during gestation on sow's performance. One hundred and seventy-four sows [Topigs TN 70 (Landrace × Large White, Topigs USA); parity 3.81 ± 0.16; initial BW = 211.57 ± 3.34 kg; backfat (BF) 13.70 ± 0.42 mm] were blocked by parity, farrowing date, balanced for BW and randomly assigned to 1 of 3 treatments in a randomized complete block design. Treatments included sows fed corn-soybean meal-based diet once at [0730 (control, T1), 1130 (T2), or 1530 h (T3)], with daily feed quantity kept at 1.25× maintenance energy intake [100 × (BW)0.75] kcal ME/d. Sows received 6,758, 7,434, and 8,110 kcal ME/d from days 30 to 60, days 61 to 90, days 91 to 109 of gestation, respectively. The gestation diet was formulated to contain 3,379 kcal of ME/kg, 0.70% Ca, 0.61% total P, 0.58% SID Lys, 0.26% SID Met, 0.45% SID Thr, 0.12% SID Trp, and 0.48% SID Met+Cys. Body weight and BF were recorded on days 30, 60, 90, and 109 of gestation, 24 h after farrowing and at weaning. Results showed that feeding times evaluated did not alter BW changes from day 30 to day 109 of gestation (P = 0.81) or from day 30 to weaning (P = 0.87). Similarly, feeding sows daily at 1130 h did not influence BF gains and sow reproductive performance relative to the control sows (P > 0.10). Sows fed once daily at 1530 h gained more BF compared with the control (3.69 ± 0.47 vs. 2.12 ± 0.50 mm, P = 0.04) from day 30 to day 109 of gestation. From day 30 of gestation to weaning, treatments did not influence BF gain (P = 0.24). Feeding sows daily meal at 1530 h had propensity to increase (P = 0.09) the number of piglets weaned by 0.54 piglets compared with the control sows. In conclusion, the present study demonstrated that feeding pregnant sows at 1530 h altered energy and nutrient metabolism improving their BF gain and exhibited a potential to increase the number of weaned piglets compared with conventional feeding regime.

Effect of feeding frequency and sow parity based on isocaloric intake during gestation on sow performance.

The aim of this study was to investigate the effect of feeding frequency and sow parity based on same rate of maintenance energy intake during gestation on sow performance. One hundred and seventy-seven sows [Topigs Norsvin 70, Landrace × Large White, Topigs Norsvin USA, Burnsville, MN; parity 3.80 ± 0.16; initial BW = 211.34 ± 3.37 kg; backfat (BF) 13.57 ± 0.54 mm] were blocked by parity, balanced for BW, and randomly assigned to 1 of 3 treatments in a randomized complete block design. Treatments included sows fed corn-soybean meal-based diet 1× daily at 0730 h (control, T1), 2× daily [half ration at 0730 and 1530 h (T2)], or 3× daily [a third portion at 0730, 1130, and 1530 h (T3)], with daily feed quantity kept at 1.25 × maintenance energy intake [100 × (BW)0.75] kcal ME/d. Treatments were imposed from day 30 of gestation. Sows received on average 6,921, 7,129, and 7,399 kcal ME/d from days 30 to 60, days 61 to 90, days 91 to 109 of gestation, respectively. Feeding frequency during gestation had no effect on lactation ADFI (P > 0.10). Sows fed 3× daily during gestation had improved lactation G:F (P = 0.040) compared with sows fed 2× but similar to control sows (P = 0.338). Treatment did not alter BW or BW variations during gestation, lactation, or from days 30 to wean (P > 0.10). Sows fed 2× daily had tendency to gain BF from day 30 to day 109 of gestation (P = 0.053) but tended to lose BF during lactation (P = 0.091) relative to the control sows. Feeding frequency (2× and 3× daily) tended to increase the number of piglets weaned by 0.40 (P = 0.056) and 0.53 (P = 0.098) piglets, respectively, compared with control sows. Sows fed 2× daily during gestation had reduced number of stillborn relative to control sows (P = 0.035). From day 30 to wean, gilts had propensity to lose BF relative to P1+ (P = 0.094), but lost BF compared with P3+ and P6+ sows (P = 0.003). Parity P6+ sows had highest percentage of both 72 h and preweaning piglet mortality than P0, P1+, and P3+ sows (P < 0.05). In conclusion, parity (P6+) had greater lactation BW gain but higher mortalities relative to lower parity sows. Sows fed 2× daily tended to gain BF from days 30 to 109 of gestation and had reduced number of stillborn relative to control sows. It appears that increasing gestation sow feeding frequency from 1× daily to 2× and 3× daily may reduce the number of stillborn and increase litter size at weaning although most of the reproductive traits were not affected.

Assessment of the efficacy of an attenuated live marker classical swine fever vaccine (Flc-LOM-BErns) in pregnant sows.

Here, we constructed an attenuated live marker classical swine fever (CSF) vaccine (Flc-LOM-BErns) to eradicate CSF. This was done by taking infectious clone Flc-LOM, which is based on an attenuated live CSF vaccine virus (LOM strain), and removing the full-length classical swine fever virus (CSFV) Erns sequences and the 3' end (52 base pairs) of the CSFV capsid. These regions were substituted with the full-length bovine viral diarrhoea virus (BVDV) Erns gene sequence and the 3' end (52 base pairs) of the BVDV capsid gene. Sows were vaccinated with the Flc-LOM-BErns vaccine 3 weeks before insemination and then challenged with virulent CSFV at the early, mid- or late stages of pregnancy. We then examined transplacental transmission to the foetuses. Piglets born to sows vaccinated with Flc-LOM-BErns did not show vertical infection, regardless of challenge time. In addition, CSFV challenge did not affect the delivery date, weight or length of the foetus. Pregnant sows inoculated with the Flc-LOM-BErns vaccine were anti-CSF Erns antibody-negative and anti-BVDV Erns antibody-positive. Challenge of pregnant sows with virulent CSFV resulted in anti-CSF Erns antibody positivity. These results strongly indicate that differential diagnosis can be conducted between the Flc-LOM-BErns vaccinated animal and virulent CSFV affected animal by detecting antibody against BVDV Erns or CSF Erns gene. Therefore, the Flc-LOM-BErns vaccine may fulfil the function of differential diagnosis which required for DIVA vaccine.