Exploring Hyperprolific Sows: A Study of Gross Morphology of Reproductive Organs and Oxytocin Receptor Distribution across Parities.

This study investigated the gross morphology of reproductive organs and oxytocin receptor distribution across different parities in hyperprolific sows. A total of thirty-two reproductive organs from Landrace × Yorkshire crossbred sows were categorized into three groups based on parity numbers: 1 (n = 10), 2-5 (n = 12), and ≥6 (n = 10). All sows were culled due to management problems, and none had reproductive disorders. A gross morphology examination of the ovaries, uterus, and the rest of the reproductive tract was conducted. Using immunohistochemistry, the levels of oxytocin receptor were evaluated in five layers of the uterus, the epithelial, superficial glandular, deep glandular, and circular and longitudinal smooth muscles of the myometrium, and were quantified using an H-score. On average, the age and body weight of sows and the total number of piglets born per litter were 799.8 ± 327.8 days, 213.2 ± 31.7 kg, and 15.5 ± 4.8, respectively. The numbers of ovulations in sows in parity number 1 (19.9 ± 2.4) were lower than those in sows in parity numbers 2-5 (29.7 ± 2.0, p = 0.004) and ≥6 (27.7 ± 2.1, p = 0.022). The uterine weights of sows in parity number 1 (902.9 ± 112.5 g) were lower than those of parity numbers 2-5 (1442.1 ± 111.8 g, p = 0.001) and ≥6 (1394.3 ± 125.1 g, p = 0.004). The length of the uterus in sows with parity number 1 (277.9 ± 26.1 cm) was shorter than those in sows with parity numbers 2-5 (354.6 ± 25.9 cm, p = 0.033) and tended to be shorter than those in sows with parity numbers ≥ 6 (346.6 ± 29.0 cm, p = 0.068). The immunolocalization of oxytocin receptors could be detected in various parts of the porcine endometrium and myometrium. Among the five tissue layers of the uterus, the H-score of oxytocin receptors in the deep uterine glands was greater than in the superficial uterine glands (p = 0.023) and the circular muscle layer of the myometrium (p = 0.011), but it did not differ from the epithelial layer of the endometrium (p = 0.428) or the longitudinal muscle layer of the myometrium (p = 0.081). Sows with parity numbers ≥ 6 had a lower oxytocin receptor H-score than those with parity numbers 1 (p < 0.001) and 2-5 (p < 0.001). In conclusion, these data emphasize the notable variations in several reproductive parameters and the levels of oxytocin receptor within the uterus of hyperprolific sows. Across the majority of uterine tissue layers, there was a marked decrease in the H-score of the oxytocin receptor in the older sows.

Large litters have a detrimental impact on litter performance and postpartum maternal behaviour in primiparous sows.

BACKGROUND: Our previous study confirmed that large litter size adversely affects prepartum maternal hormones and behaviour, concurrently with heightened oxidative stress in primiparous sows. The purpose of this study was to examine the effect of large litter size on litter performance, postpartum maternal behaviour, salivary cortisol levels, and colostral immunoglobulin levels in sows, as well as investigate their correlations with the levels of oxidative stress parameters. RESULTS: A total of 24 primiparous sows (Landrace[Formula: see text]Large white) and their offspring were categorised into two groups based on litter size: NORMAL (n = 8) with litter size ranging from 7 to 14 (mean 11.5[Formula: see text]2.7), and LARGE (n=16) with litter size ranging from 15 to 20 (mean 15.9[Formula: see text]1.4). All sows were housed in a group housing system during gestation and transitioned to an adaptable loose housing system (2.4[Formula: see text]2.3 m) during the farrowing and lactation periods. The nursing and carefulness behaviour of the sows was monitored over a 24-h period between 72 and 96 h after parturition. Saliva samples were collected for cortisol assay on 35, 21, and 7 days before parturition (D-35, D-21, and D-7, respectively), as well as on days 1, 7, and 28 after parturition (D1, D7, and D28, respectively). On D1, higher piglet mortality rates were observed among the LARGE group compared to the NORMAL group (p<0.01). The total and successful nursing behaviours of the sows were less frequent in the LARGE group than in the NORMAL group (p<0.05, for both), and the carefulness score of the LARGE group was also lower than that of the NORMAL group (p< 0.01). On D1, cortisol levels in LARGE sows were higher than those in NORMAL sows (p< 0.05), and for other time points (D-21, D-7, D7, and D28), cortisol levels in LARGE sows tended to be higher than those in NORMAL sows (p < 0.10, for all). Successful nursing behaviour displayed negative correlations with levels of salivary cortisol and certain oxidative stress parameters measured on D1. CONCLUSIONS: These findings suggest that the strategy for alleviating physiological and oxidative stress during the peripartum periods could benefit potential postpartum maternal behaviour and litter performance in the sows with large litters.

Genetic basis of sow hyperprolificacy and litter size optimization based on a genome-wide association study.

Over the last few decades, there has been a constant increase in sow litter size, the consequences of which include parturition duration extension, an increase in the percentage of stillborn and hypoxic piglets, and increased variation in piglet birth weight, which reduces their vitality. As such, it seems clear that further increasing sow fertility will generate difficulties and costs in rearing numerous litters with low birth weights. Therefore, the current study aimed to analyze the genetic background of sow hyperprolifcacy using a genome-wide association study (GWAS). The research included 144 sows in the maternal component, divided into two equal groups. The first group (control) consisted of females giving birth to the optimal number of piglets in their third and fourth litters (14-16), while the second group (cases) included those with excessive litter size (>16). The analyzed sows were genotyped using Illumina's PorcineSNP60v2 BeadChip microarray, comprising 64,232 single nucleotide polymorphisms (SNPs). Statistical analysis using R included quality control of genotyping data and GWAS analysis based on five logistic regression models (dominant, codominant, overdominant, recessive, and log-additive) with a single SNP marker as the explanatory variable. On this basis, one SNP (SIRI0000069) was identified on chromosome seven within the EFCAB11 (EF-hand calcium binding domain 11) gene that had a statistically significant effect on sow hyperprolificacy. Additionally, ten SNPs (INRA0007631, ALGA0011600, ALGA0043433, ALGA0043428, M1GA0010535 ALGA00443338, ALGA0087116, MARC0056787, ALGA0112928, and ALGA0089047) had a relationship with the analyzed feature at a level close to significance, set at 1-5. These SNPs appear important since they are located on chromosomes on which a large number of quantitative trait loci (QTLs) and SNPs associated with reproductive characteristics, including litter size, have been identified.

Factors associated with farrowing assistance in hyperprolific sows.

OBJECTIVE: The present study was performed to determine risk factors associated with the frequency of farrowing assistance in hyperprolific sows in a tropical environment and to investigate the impacts of farrowing assistance on piglet colostrum consumption and sow colostrum yield. METHODS: Farrowing data from 352 Landrace×Yorkshire crossbred sows and 5,554 piglets in five commercial swine herds in Thailand were investigated. The sows were classified according to parity numbers: 1 (n = 72), 2 to 4 (n = 128), 5 to 6 (n = 84), and ≥7 (n = 68) and the total number of piglets born per litter (TB): 10 to 13 (n = 90), 14 to 16 (n = 117), and ≥17 (n = 145). The incidence of farrowing assistance and associated parameters were investigated. RESULTS: The TB and farrowing duration averaged 15.8±0.2 and 279.9±11.2 min, respectively. The percentage of sows that required farrowing assistance was 29.8% and varied among herds from 5.7% to 53.3% (p<0.001). The percentage of piglets born after birth assistance using manual intervention was 8.4%. Sows with parity numbers 1 and 2 to 4 had a lower frequency of farrowing assistance than sows with parity numbers ≥7 (p<0.01). The colostrum yield of sows that required farrowing assistance did not differ from sows that farrowed without assistance (5.3±0.2 and 5.1±0.1 kg; p = 0.288); however, the colostrum consumption of piglets born from sows that required farrowing assistance was lower than those born from sows that farrowed without assistance (302.2±15.7 and 354.2±5.6 g; p<0.001). Blood oxygen saturation of the piglets born after birth assistance tended to be lower than the piglets that farrowed without birth assistance (87.8%±1.3% vs 90.4%±0.4%; p = 0.054). CONCLUSION: The frequency of farrowing assistance in sows varied among herds and was influenced by parity number. The piglets born after receiving birth assistance should receive special care to improve their blood oxygen saturation and enhance colostrum intake.

Analysis of Early Growth of Piglets from Hyperprolific Sows Using Random Regression Coefficient.

Management of hyperprolific sows is challenging when it comes to controlling birth weight variability and piglet survival in large litters. The growth of low birth weight piglets can be compromised and have a negative impact on production efficiency. The objective of the study was to apply a random regression coefficient model to estimate the main effects of the growth of piglets of highly prolific sows. The dataset contained growth data for 360 piglets from 25 Pen Ar Lan Naima sows. In addition to routine procedures after farrowing, piglets were weighed five times: on day 1 after farrowing, on day 14 of life, at weaning on day 28, on day 30 of nursery period, and at the end of the nursery period when piglets were 83 days old. Data were treated as longitudinal, with body weight as the dependent variable. Fitting age as a quadratic regression within piglets in the random part of the model helped to determine the significant effect of birth weight, litter size, and parity on the growth of the piglets. Since the piglets from large litters often have non-uniform birth weights and this can affect further growth, the use of a random regression coefficient model is practical for analysing the growth of such piglets due to the ability to describe the individual growth pattern of every individual.

Large litter size increases oxidative stress and adversely affects nest-building behavior and litter characteristics in primiparous sows.

The study examined 24 primiparous sows (Landrace × Large white) and their offspring, which were grouped based on litter size: NORMAL (n = 8, average litter size 11.5 ± 1.2), with litter size between 7 and 14, and LARGE (n = 16, average litter size 15.9 ± 1.0), with litter size between 15 and 20. Sows were group-housed during gestation, and housed in an adjustable loose housing system (2.4 × 2.3 m) during farrowing and lactation. All the sows were confined in the farrowing crates (0.6 × 2.3 m) for 7 days after the onset of parturition. Saliva samples of sows were collected on days 35, 21, and 7 before farrowing (D-35, D-21 and D7, respectively), and on days 1, 7, and 28 after farrowing (D1, D7, and D28, respectively) to measure the levels of Trolox equivalent antioxidant capacity (TEAC), hydrogen peroxide (H2O2), advanced oxidation protein products (AOPP), and tumor necrosis factor-alpha (TNF-α). Colostrum samples were collected for oxytocin and prolactin assays. Nest-building behavior (NB) for 24 h before parturition and farrowing was observed through video analysis. The results showed that LARGE sows had higher levels of H2O2 on D1 and D7 and AOPP during late gestation (p < 0.05, for all) and lower TEAC levels during late gestation and on D7 and D28 after farrowing (p < 0.05, for all) than NORMAL sows. Additionally, LARGE sows tended to have higher levels of TNF-α on D1 and D7 (p < 0.10, for both). LARGE sows showed shorter duration and lower frequency of NB during 24-12 h before parturition (p < 0.05, for both), and tended to have lower prolactin levels (p = 0.10). Furthermore, large sows tended to show longer farrowing duration and higher stillbirth rate (p = 0.06, p = 0.07, respectively). In conclusion, this study confirmed that large litter size may increase oxidative stress in sows during late gestation and lactation. The data also suggested that this could adversely impact prolactin release, leading to reduced NB.

Offspring of hyper prolific sows: Immunity, birthweight, and heterogeneous litters.

In Europe, in the last 3 decades, there has been a constant increase in litter size due to the use of superior maternal line genetics. Those sows giving birth to more piglets than their average number of functional teats are identified as hyperprolific sows (HPS). The large number of piglets born within a litter implies not only a challenge for their access to vital resources like colostrum and milk but has a direct effect on their average birth weight and heterogeneity. These conditions are detrimental to piglets' vitality in the first hours of life and also to their immunity development. An exceptionally large number of growing fetuses in HPS leads to intrauterine crowding and consequently to an increased number of piglets suffering from intrauterine growth retardation (IUGR), which put piglets at a high risk of mortality after birth and up to later stages of life. Increased heterogeneity of birth weight within large litters increases the competition for colostrum intake, with the smaller piglets being less competitive and vital, and therefore affecting negatively their immunity. Low birth weight, long interval to reach the udder, and long duration of farrowing, all have negative effects on piglets' immunoglobulin absorption. In HPS litters, colostrum management should be focused on low birth weight piglets, anticipating their impaired capabilities associated with ingesting adequate colostrum, by shortening the time to reach the udder and reducing competition among piglets. The vitality of neonate piglets, especially low in birth weight or affected by IUGR should be enhanced to improve their body temperature and their early life stage energy metabolism.

Body weight of newborn and suckling piglets affects their intestinal gene expression.

Modern hyperprolific sows must deal with large litters (16-20 piglets) which reduce piglet birthweight with a concomitant increase in the proportion of small and intrauterine growth retarded piglets. However, larger litters do not only have a greater variation of piglet weights, but also a greater variation in colostrum and milk consumption within the litter. To further understand the impact that body weight has on piglets, the present study aimed to evaluate the degree of physiological weakness of the smallest piglets at birth and during the suckling period (20 d) compared to their middle-weight littermates through their jejunal gene expression. At birth, light piglets showed a downregulation of genes related to immune response (FAXDC2, HSPB1, PPARGC1α), antioxidant enzymes (SOD2m), digestive enzymes (ANPEP, IDO1, SI), and nutrient transporter (SLC39A4) (P < 0.05) but also a tendency for a higher mRNA expression of GBP1 (inflammatory regulator) and HSD11ß1 (stress hormone) genes compared to their heavier littermates (P < 0.10). Excluding HSD11ß1 gene, all these intestinal gene expression differences initially observed at birth between light and middle-weight piglets were stabilized at the end of the suckling period, when others appeared. Genes involved in barrier function (CLDN1), pro-inflammatory response (CXCL2, IL6, IDO1), and stress hormone signaling (HSD11ß1) over-expressed compared to their middle-weight littermates (P < 0.05). In conclusion, at birth and at the end of suckling period, light body weight piglets seem to have a compromised gene expression and therefore impaired nutrient absorption, immune and stress responses compared to their heavier littermates.

Under hyperprolific situations, piglets must deal with a reduced birthweight and a severe sibling competition for nutrients. Therefore, light body weight newborn and suckling piglets may also have physiological disadvantages compared to their middle-weight littermates. To further understand the impact that body weight has on piglets, the present study aimed to evaluate the degree of physiological weakness of the smallest piglets at birth and during the suckling period (20 d) compared to their middle-weight littermates through their jejunal gene expression. Newborn light piglets downregulated genes related to immunity, antioxidant, and digestive activities, but also a tendency to upregulate other genes related to inflammation and stress responses. At the end of the suckling period, those genes expression differences vanished while others appear. Light weight piglets showed lower expression of genes involved in barrier function, inflammation, and stress responses compared to their middle-weight littermates. At birth and at the end of lactation, light piglets seem to have a compromised intestinal gene expression for nutrient absorption, immune and stress responses compared to their heavier littermates.

Evaluation of an on-farm method to assess colostrum IgG content in hyperprolific sows.

The colostrum quality (immunoglobulin content) is one of the most challenging aspects for hyperprolific sows in the modern pig industry. The objective of this study was to evaluate relationships among sow body condition scores, litter characteristics, and colostrum IgG content in hyperprolific sows, using a digital Brix refractometer to measure IgG. Samples (5 ml) were collected from two hundred and eighty-seven sows within the first hour postpartum. Sow parameters and back fat thickness at farrowing (BFF) and weaning (BFW) were recorded. The results indicate a positive correlation between parity and IgG, as well as BFF and BFW. A negative correlation was found between the number of weaning piglets and BFW. Moreover, a positive correlation was observed between the number of mummified piglets and colostrum IgG. Finally, lactation duration was positively associated with BFF. In conclusion, the number of mummified piglets is a factor positively associated with colostrum IgG content in hyperprolific sows.

Identifying Risk Factors for Low Piglet Birth Weight, High Within-Litter Variation and Occurrence of Intrauterine Growth-Restricted Piglets in Hyperprolific Sows.

This study aimed to identify risk factors affecting PBW, high CVPBW and the occurrence of IUGR piglets in 12 commercial Danish herds with hyperprolific sows using free-access stalls, floor or electronic sow feeding systems in the gestation unit. The following factors were investigated: the duration of previous lactation, the length of the interval from weaning to insemination, the length of gestation, litter size, parity, sow backfat thickness in late gestation and the type of feeding system in the gestation unit. The study included newborn piglets from 452 litters with the following production indicator averages: 21.3 piglets/L, 1235 g PBW, 22.9% CVPBW and 10.9% and 11.8% within-litter occurrence of severe and mild IUGR piglets, respectively. Increasing length of weaning-to-insemination interval decreased PBW by 25.8 g/day. For 2nd to 9th parity sows, each additional piglet in the litter increased CVPBW by 0.38%, the occurrence of severe IUGR piglets by 0.68% and mild IUGR piglets by 0.50%. Sows of 5th parity and older had a 1.39% higher CVPBW and 49.1 g lighter piglets compared with sows of 2nd to 4th parity. PBW was lower in one ESF herd, suggesting complex interactions that need to be further elucidated. The main critical risk factor observed was litter size.

Prenatal Exposure to Innately Preferred D-Limonene and Trans-Anethole Does Not Overcome Innate Aversion to Eucalyptol, Affecting Growth Performance of Weanling Piglets.

In the present research, two studies were performed to determine the effects of specific botanical compounds (BCs) on the innate feed preference and feed intake of piglets, as follows: Exp. 1 studied the innate feed preferences of post-weaning piglets using a double-choice feeding test. A total of 828 weaned piglets were distributed into 36 pens (23 pigs/pen) and assigned to three dietary pair choice feeding options (n = 12): unsupplemented prestarter diets (reference) versus reference plus D-limonene, trans-anethole, or eucalyptol. Piglets showed a preference for diets with D-limonene (53.8%) and trans-anethole (54.5%), and an aversion to eucalyptol (41.6%) (p < 0.05). Exp. 2 studied whether the prenatal and perinatal exposure to D-limonene, trans-anethole, and eucalyptol influences the feed intake and growth of newly-weaned piglets. Twenty-eight gestating and lactating sows were distributed into two dietary treatments (n = 14): unsupplemented Control diets or Control plus a blend of BCs (BBC; containing D-limonene, trans-anethole, and eucalyptol). D-limonene, trans-anethole, and eucalyptol were transferred into the placental fluid, and D-limonene and trans-anethole into the milk (p < 0.05). Furthermore, weanling piglets (n = 200; Control) and (n = 203; BBC) received the same treatment as their mothers in prestarter diets. The early response after weaning showed that piglets' post-weaning BW gain was higher in the Control (p < 0.05) group than in those exposed to BBC. In conclusion, prenatal exposure to preferred D-limonene and trans-anethole, or familiarity to eucalyptol did not help to overcome the innate aversion to eucalyptol and its negative effect on weanling piglets' BW.

Phytogenic Compounds Supplemented to Gestating Hyperprolific Sows Affects the Gut Health-Related Gene Expression and Histological Responses in Neonate Piglets.

This research aims to determine whether a specific blend of phytogenic compounds (BPC) supplemented in gestating hyperprolific sow diets can promote prenatal maternal effects in terms of piglet gut function and morphology. Twenty-eight (Landrace × Yorkshire) gilts and sows (parity 0 to 7) were randomly distributed by parity number and body weight into two dietary treatments: unsupplemented Control (CON) (n = 14) or CON diet supplemented with 1 g/kg feed of BPC during gestation (n = 14). The BPC supplementation during gestation of sows downregulated the neonate piglets' jejunal genes involved in oxidation (SOD2) and nutrient transport (SLC16A1/MCT1, SLC11A2/DMT1, and SLC39A/ZIP4), while IFNG and CLDN4 related to immune response and barrier function, respectively, were upregulated (q < 0.10). In addition, the jejunal villus height and the ratio of the villus height to crypt depth tended to increase (p < 0.10), while goblet cell volume density was higher (p < 0.05) in BPC compared to CON. In conclusion, dietary supplementation of BPC in gestating diets for hyperprolific sows influences neonatal histomorphology and expression of genes related to the intestinal function and health.

Phytogenic actives supplemented in hyperprolific sows: effects on maternal transfer of phytogenic compounds, colostrum and milk features, performance and antioxidant status of sows and their offspring, and piglet intestinal gene expression.

Phytogenic actives (PA) are plant-derived natural bioactive compounds that may promote livestock health and well-being, as well as improve growth performance and production efficiency. The current study aims to evaluate their effects on sows and their offspring. Eighty-one hyperprolific sows (up to parity 7) were assigned to 3 experimental treatments. Control sows were offered a nonsupplemented diet during gestation and lactation, and treated sows were fed the control diet supplemented with 1 g/kg of a blend of PA (BPA) in lactation (L) or during gestation and lactation (GL). An evaluation was made of placental and milk maternal transfer of these BPA and colostrum-milk features, sows and piglets antioxidant status, reproductive performance (litter size), body weight (BW) changes, weaning-estrus interval, and litter performance. Finally, piglet´s jejunum gene expression was measured. The BPA supplementation during gestation (GL) increased the number of piglets born alive (P = 0.020) and reduced (P < 0.05) the newborn piglets BW, while there were no differences among treatments on the suckling (day 20) and weaned (day 7) piglets BW (P > 0.05). Dietary phytogenic volatile compounds reached GL placental fluid, and milk of L and GL sows (P < 0.05). Moreover, colostrum protein in GL and milk fat content in L and GL were increased (P < 0.05). Milk of GL showed inhibitory activity against Bacillus subtilis and Staphylococcus aureus (P < 0.05). Antioxidant status of GL sows showed an enhanced (P < 0.05) of catalase (CAT) and total antioxidant capacity levels at early gestation (day 35), whereas higher levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) enzymes at late gestation (day 110). Likewise, GL newborn piglets showed higher CAT levels, whereas both CAT and SOD levels in suckling piglets, as well as CAT, SOD, and GSH-Px in weaned piglets, were increased in L and GL (P < 0.05). Jejunum messenger ribonucleic acid abundance of suckling piglets in L and GL groups showed overexpression of barrier function MUC2, digestive enzyme IDO, and immune response PPARGC-α, TNF-α, TGF-ß1, and IL-10 genes (P < 0.05). In conclusion, dietary BPA supplementation in hyperprolific sows increased the litter size (born alive) and improved the composition and bioactivity of colostrum and milk, besides, modified the antioxidant status of sows and their offspring, as well as the suckling piglets gut health gene expression. Several BPA volatile compounds were prenatal and postnatal maternally transferred (placental fluid and milk).