Birth Weight Pigs Research Articles

A genome-wide association study reveals candidate genes and regulatory regions associated with birth weight in pigs.

Piglet birth weight is associated with preweaning survival, and its related traits have been included in the breeding program. Thus, understanding its genetic basis is essential. This study identified four birth weight-associated genomic regions on chromosomes 2, 4, 5, and 7 through genome-wide association study analysis in 7286 pigs from three different pure breeds using the FarmCPU model. The genetic and phenotypic variance explained by the four candidate regions is 8.42% and 1.85%, respectively. Twenty-eight candidate genes were detected, of which APPL2, TGFBI, MACROH2A1, and SEC22B have been reported to affect body growth or development. In addition, 21 H3K4me3-enriched peaks overlapped with the birth weight-associated genomic regions were identified by integrating the genome-wide association study results with our previous ChIP-seq and RNA-seq data generated in the pig placenta, a fetal organ relevant to birth weight, and three of the regulatory regions influence TGFBI, MACROH2A1, and SEC22B expression. This study provides new insights into understanding the mechanisms for birth weight. Further investigating the variants in the regulatory regions would help identify the functional variants for birth weight in pigs.

Comprehensive Analysis of Placental DNA Methylation Changes and Fetal Birth Weight in Pigs.

Birth weight is a complex multifactorial trait relevant to health states and disease risks in later life. The placenta is essential for proper fetal growth and facilitates gas, nutrient, and waste exchange between the mother and developing fetus. How changes in placental DNA methylation affect fetal birth weight remains to be fully elucidated. In this study, we used whole-genome bisulfite sequencing and RNA sequencing to reveal a global map of DNA methylation and gene expression changes between the placentas of highest birth weight and lowest birth weight piglets in the same litters. The transcriptome analysis identified 1682 differential expressed genes and revealed key transcriptional properties in distinct placentas. We also identified key transcription factors that may drive the differences in DNA methylome patterns between placentas. The decrease in DNA methylation level in the promoter was associated with the transcriptional activation of genes associated with angiogenesis, extracellular matrix remodeling, and transmembrane transport. Our results revealed the regulatory role of DNA methylation in gene transcription activity leading to the differences in placental morphological structures and birth weights of piglets. These results could provide novel clues to clarify the underlying regulatory mechanisms of placental development and fetal growth.

Maternal Hypermethylated Genes Contribute to Intrauterine Growth Retardation of Piglets in Rongchang Pigs.

The placenta is a crucial determinant of fetal survival, growth, and development. Deficiency in placental development directly causes intrauterine growth retardation (IUGR). IUGR can lead to fetal growth restriction and an increase in the mortality rate. The genetic mechanisms underlying IUGR development, however, remain unclear. In the present study, we integrated whole-genome DNA methylation and transcriptomic analyses to determine distinct gene expression patterns in various placental tissues to identify pivotal genes that are implicated with IUGR development. By performing RNA-sequencing analysis, 1487 differentially expressed genes (DEGs), with 737 upregulated and 750 downregulated genes, were identified in IUGR pigs (H_IUGR) compared with that in normal birth weight pigs (N_IUGR) (p < 0.05); furthermore, 77 miRNAs, 1331 lncRNAs, and 61 circRNAs were differentially expressed. The protein-protein interaction network analysis revealed that among these DEGs, the genes GNGT1, ANXA1, and CDC20 related to cellular developmental processes and blood vessel development were the key genes associated with the development of IUGR. A total of 495,870 differentially methylated regions were identified between the N_IUGR and H_IUGR groups, which included 25,053 differentially methylated genes (DMEs); moreover, the overall methylation level was higher in the H_IUGR group than in the N_IUGR group. Combined analysis showed an inverse correlation between methylation levels and gene expression. A total of 1375 genes involved in developmental processes, tissue development, and immune system regulation exhibited methylation differences in gene expression levels in the promoter regions and gene ontology regions. Five genes, namely, ANXA1, ADM, NRP2, SHH, and SMAD1, with high methylation levels were identified as potential contributors to IUGR development. These findings provide valuable insights that DNA methylation plays a crucial role in the epigenetic regulation of gene expression and mammalian development and that DNA-hypermethylated genes contribute to IUGR development in Rongchang pigs.

Effects of Farrowing Induction on Some Farrowing Characteristics in the Pig − A Review

Abstract Several farrowing induction programs have been used to increase the proportion of sow farrowing during the work period and the rate of farrowing supervision, as well as to promote the success of cross-fostering and the practice of all-in all-out in swine production. The present overview aimed to evaluate the effects of farrowing induction on farrowing duration, birth interval, birth weight, dystocia/birth assistance, and stillbirth in pigs. The results showed that via different routes of administration, either natural or synthetic prostaglandins alone or in combination mostly with uterotonic drugs, including oxytocin and carbetocin, have been used for the induction of farrowing. Sometimes other drugs, such as dexamethasone, estradiol, xylazine, ergometrine, and AGN190851, were added. Vulvar and perinatal routes reduced the intramuscular dose of prostaglandins by 50% to 75%, while equal effects remained. A split dose of prostaglandin 6 h apart should be used because it may enhance complete luteolysis. Additionally, if uterotonic drugs are used following prostaglandin injection, they should be injected after the birth of the first piglets at the earliest timepoint to ensure full opening of the cervix. These two practices decrease the farrowing duration, the birth interval, and dystocia. Induction should not be conducted more than 2 days earlier than the expected farrowing date in order to keep the stillbirth rate and birth weight unaltered. This review also revealed that certain factors, such as the rate of farrowing supervision, natural differences in piglets’ birth weights, litter size, gestation length, and treatment with altrenogest before induction, may be confounding factors that possibly alter the effect of induction programs on certain farrowing characteristics.

Timing of dietary zinc additions during gestation for improved piglet survival.

The objectives of this study were to determine a practical approach to feeding elevated dietary zinc (Zn) to gestating sows in a commercial setting and to confirm preweaning mortality could be reduced by feeding high Zn to sows during different periods of gestation. The study was conducted at a commercial sow farm in the upper Midwest. Mixed parity sows (n = 267) over three consecutive weekly farrowing groups (sows farrowing within 1wk) were assigned randomly to one of the three dietary treatments within parity. Treatments consisted of: (1) control sows fed a corn-soybean meal diet containing 206mg/kg total supplemental Zn supplied by zinc hydroxychloride; (2) breed-to-farrow: as control + 147mg/kg supplemental Zn as ZnSO4 (353mg/kg total supplemental Zn) fed from 5 d after breeding to farrowing; and (3) day 110-to-farrow: as control fed from breeding to farrowing + 4,079mg/kg supplemental Zn as ZnSO4 (4,285mg/kg total supplemental Zn) starting day 110 of gestation until farrowing. At farrowing, individual piglets were weighed and identified within 12h of birth. Data were analyzed using PROC GLIMMIX of SAS and the model considered the fixed effect of dietary treatment and random effect of farrowing group. Dietary treatments did not affect number of total pigs born per litter. For breed-to-farrow sows, there was an increase in the percentage of pigs born alive compared to sows fed the control and day 110-to-farrow treatments (P < 0.001). The number of stillborn pigs expressed as a percentage of total litter size at birth decreased for breed-to-farrow sows (P < 0.001) compared with control or day 110-to-farrow sows. Mortality of low birth weight piglets from birth to weaning did not differ among dietary treatments (P = 0.305); however, a trend for decreasing post-natal mortality (P = 0.068) of normal birth weight pigs was observed for pigs born to sows fed elevated Zn 5 d before farrowing. In conclusion, feeding elevated Zn to sows throughout gestation increased the proportion of pigs born alive suggesting that elevated gestational Zn intake makes piglets more robust to endure the stresses of farrowing and decreases intrapartum mortality. Under the conditions of this study, elevated Zn intake of sows did not influence piglet post-natal survival. However, feeding high zinc throughout gestation may decrease piglet mortality during the parturition process.

Muscle Fiber, Connective Tissue and Meat Quality Characteristics of Pork from Low Birth Weight Pigs as Affected by Diet-Induced Increased Fat Absorption and Preferential Muscle Marbling.

This study investigated how birth weight differences in piglets affected carcass and muscle fiber properties as well as meat quality at slaughter. Within litters, piglets were grouped according to their birth weight as either normal (NBW; 1.62-1.73 kg) or low (LBW; 1.18-1.29 kg). At 5 weeks of age, NBW piglets were randomly transitioned to control (C) or isocaloric high fat diets derived from non-dairy (HF), while LBW piglets were randomly transitioned to high fat diets derived from non-dairy (HF) or dairy sources (HFHD). Piglets were reared in individual pens under standardized housing and feeding conditions. Live weight was recorded weekly, and pigs were slaughtered at 12 weeks of age. Hot carcass weights, dressing percentages, lean meat yield, and primal cut proportions were determined. The m. longissimus thoracis was collected from the right side of the carcass for measurement of physical and chemical properties of meat and muscle fiber characteristics. Results indicated that LBW pigs compensated for their live weight compared to NBW pigs at 6 weeks of age. The mean muscle fiber diameter of LBW-HFHD group is significantly higher than NBW-C and NBW-HF group, and the type I muscle fiber diameter is significantly higher than NBW-C group. Dairy fat inclusion in LBW pig diet reduced carcass back fat thickness. This increased the calculated lean meat yield to be comparable to that of NBW pigs fed a commercial diet. Incorporating dairy-sourced high-fat into LBW pigs' diets appears to be an effective strategy for producing carcasses equivalent to NBW pigs.

105 Awardee Talk: Timing of Dietary Zinc Supplementation During Gestation did not Affect Trace Element Concentrations in Sows and Their Piglets

Abstract Gestating sows (n = 267) were used to determine if timing of high dietary zinc supplementation in a commercial setting would reduce pre-weaning mortality of pigs and influence maternal and piglet copper (Cu), iron (Fe), and zinc (Zn) concentrations. Sows from three consecutive weekly farrowing groups were assigned randomly within parity to one of three dietary treatments consisting of: 1) Control: a corn-soybean meal diet containing 125 ppm supplemental Zn supplied by zinc hydroxychloride; 2) Breed-to-Farrow (B-to-F): as Control + 141 ppm supplemental Zn as ZnSO4 (266 ppm total supplemental Zn) fed from 5 days after breeding to farrowing; and 3) Day 110-to-Farrow (D110-to-F): as the Control diet fed from breeding to farrowing + 2,715 ppm supplemental Zn as ZnSO4 (2,840 ppm total supplemental Zn) starting on day 110 of gestation until farrowing. A subset of ten sows per treatment (n = 30; average parity = 3) were selected to assess Cu, Fe, and Zn concentrations of serum, colostrum, and milk. Sera were isolated from blood collections at allotment and the day before respective farrowing date of each sow. Colostrum was collected the day of farrowing and milk on day 2 of lactation. At farrowing, two average and two low birth weight pigs from each sow (n = 122) were selected for collections of serum and tail samples at days 1 and 2 of age, respectively. The statistical model included fixed effects of treatment, farrowing group, and the random effect of their interaction. The piglet model was similar but included the random term of pig nested within sow. There were no differences in concentrations of Cu, Fe, and Zn in sow serum, milk, or colostrum attributable to dietary treatment. Piglet serum concentrations of Cu, Fe, and Zn were unaffected by feeding gestating sows high levels of supplemental zinc at any time (Table). Low birth weight pigs born to sows fed the Control diet tended (P = 0.082) to have increased concentrations of Cu in tails compared with pigs born to sows fed high zinc. In conclusion, timing of dietary zinc supplementation to gestating sows had minimal influence on concentrations of important trace elements in sows and their offspring.

113 Effect of Birth Weight on Tissue Copper, Iron, and Zinc Concentrations in Piglets

Abstract Pigs (n = 3,990) were used in a previous study to determine if supplemental zinc fed to sows at various timepoints during gestation would reduce pre-weaning mortality. Additionally, data were analyzed to evaluate the effect of birth weight on tissue concentrations and distribution of copper (Cu), iron (Fe), and zinc (Zn) in piglets. Mixed parity sows were fed 1 of 3 diets: a control corn-soybean meal diet containing 125 ppm supplemental Zn supplied by zinc hydroxychloride, a diet consisting of the control + 141 ppm supplemental Zn as ZnSO4 (266 ppm total supplemental Zn) fed from 5 days after breeding to farrowing, or the control diet fed from breeding to farrowing + 2,715 ppm of supplemental Zn from ZnSO4 (2,840 ppm total supplemental Zn) starting on day 110 of gestation until farrowing. Two low and 2 average birth weight pigs (n = 122) were selected from 10 sows per treatment group to assess Cu, Fe, and Zn concentrations of serum and tails. Serum was collected from each pig at day 1 of age and tails were collected on day 2 of age. Liver tissue was collected from a subset of pigs (n = 65) that died naturally or were euthanized within 2 days of age. The statistical model included fixed effects of treatment and farrowing group, the random effect of their interaction, and the random effect of pig nested within sow. Serum concentrations of each trace element did not differ by birth weight (Table). Low birth weight piglets had greater concentrations of Fe (P = 0.018) and Cu (P = 0.031) in their tails than average birth weight pigs. No differences were observed in tail Zn concentration by birth weight. Notably, pigs that died naturally weighed less at birth than euthanized pigs (P &amp;lt; 0.001). Moreover, pigs that died naturally had greater hepatic Fe concentrations (P &amp;lt; 0.001) and tended to have greater liver Cu concentrations (P = 0.098) compared with euthanized pigs. The associations between tissue iron and copper concentrations and birth weight of piglets may have nutritional and pathophysiological implications and thus warrant further investigation.

Exploring characteristics of placental transcriptome and cord serum metabolome associated with low birth weight in Kele pigs.

The neonate with low birth weight (LBW) resulted from intrauterine growth retardation (IUGR) exists a substantial risk of postpartum death. Placental insufficiency is responsible for inadequate fetal growth; however, the pathological mechanisms of placental dysfunction-induced IUGR in pigsremain unclear. In this study, the characteristics of placental morphology, placental transcriptome, and cord serum metabolome were explored between the Kele piglets with LBW and the ones with normal birth weight (NBW). Results showed that LBW was a common occurrence in Kele piglets. The LBW placentas showed inferior villus development and lower villi density compared to NBW placentas. There were 1024 differentially expressed genes (DEGs) identified by transcriptome analysis between the LBW and NBW placentas, of which 218 and 806 genes were up- and down-regulated in the LBW placentas, respectively. PPI network analysis showed that ITGB2, CD4, IL6, ITGB3, LCK, RAC2, CD8A, JAK3, TYROBP, and CXCR4 were hub genes in all DEGs. From GO and KEGG enrichment analysis, DEGs were primarily enriched in immunological response, cell adhesion, immune response, cytokine-cytokine receptor interaction, and PI3K-Akt signaling pathway. By using metabolomic analysis, a total of 115 differential metabolites in the cord serum of LBW and NBW piglets were found, mostly linked to amino acid metabolism and sphingolipid metabolism. In comparison to NBW piglets, LBW piglets had lower levels of arginine, isoleucine, and aspartic acid in the cord. Taken together, these data revealed dysplasia of the placental villus, insufficient supply of nutrients, and abnormal immune function of the placenta may be associated with the occurrence and development of LBW in Kele pigs.

Branched-chain amino acid supplementation does not enhance lean tissue accretion in low birth weight neonatal pigs, despite lower Sestrin2 expression in skeletal muscle.

Postnatal muscle growth is impaired in low birth weight (L) neonatal pigs. Leucine supplementation has been established as a dietary intervention to enhance muscle growth in growing animals. The aim of this study was to investigate the efficacy of supplementing L neonatal pig formulas with branched-chain amino acids (B) to enhance the rate of protein accretion. Twenty-four 3-day old pigs were divided into two groups low (L) and normal birth weight (N) based on weight at birth. Pigs were assigned to a control (C) or 1% branched-chain amino acids (B) formulas, and fed at 250mL·kg body weight -1·d-1 for 28 d. Body weight of pigs in the L group was less than those in the N group (P < 0.01). However, fractional body weight was greater for L pigs compared with their N siblings from day 24 to 28 of feeding regardless of formula (P < 0.01). In addition, feed efficiency (P < 0.0001) and efficiently of protein accretion (P < 0.0001) were greater for L than N pigs regardless of supplementation. Pigs fed the B formula had greater plasma leucine, isoleucine, and valine concentrations compared with those fed the C formula (P < 0.05). Longissimus dorsi Sestrin2 protein expression was less for pigs in the L group compared with those in the N group (P < 0.01), but did not result in a corresponding increase in translation initiation signaling. Longissimus dorsi mRNAexpression of BCAT2 was less for LB pigs compared with those in the LC group, and was intermediate for NC and NB pigs (P < 0.05). Hepatic mRNA expression of BCKDHA was greater for pigs in the L compared with those in the N groups (P < 0.05). However, plasma branched-chain keto-acid concentration was reduced for C compared with those in the B group (P < 0.05). These data suggest that branched-chain amino acid supplementation does not improve lean tissue accretion of low and normal birth weight pigs, despite a reduction in Sestrin2 expression in skeletal muscle of low birth weight pigs. The modest improvement in fractional growth rate of low birth weight pigs compared with their normal birth weight siblings was likely due to a more efficient dietary protein utilization.

Genetic and phenotypic time trends of litter size, piglet mortality, and birth weight in pigs

IntroductionLitter size in pigs has increased steadily since 1990. Because of unfavorable genetic correlations with piglet mortality, breeding goals should include survival traits next to litter size. Unbalanced breeding programs that neglect this requirement have produced increased mortality levels, attracting negative public attention. Balanced breeding does not have this disadvantage, but the general public is largely unaware of this.MethodsWe present long-term time trends as realized in commercial breeding. The data includes (i) phenotypes of litter size, piglet birth weight, and piglet mortality, as used in routine breeding value estimation; and (ii) the genomic Best Linear Unbiased Prediction (gBLUP) estimated breeding values thus obtained. Piglet mortality (2001–2022) and birth weight (2009–2022) phenotypes were related to litter size by recording year. Estimated breeding values (EBVs) for the mortality traits were regressed on those for litter size by birth year (2012–2022).ResultsAverage litter size is very weakly correlated to the mortality (R2 ≤ 0.06) and birth weight (0.07 ≤ R2 ≤ 0.26) traits, and those correlations are unfavorable (antagonistic) within each year. However, all traits analyzed here show favorable simultaneous phenotypic and genetic trends over time: the antagonisms are neutralized by balanced breeding. Above the annual mean litter size level, farrowing and lactation mortality rates increased with increasing litter size in every year (unfavorable), but the annual intercepts and the slopes decreased from 2001 to 2022 (favorable). Average litter birth weight decreased with litter size in every year (unfavorable), but the annual intercepts increased and the slopes decreased from 2009 to 2022 (favorable). The within-litter birth weight variation coefficient increased with litter size in every year (unfavorable), but the annual intercepts decreased from 2009 to 2022 (favorable). The proportion of low birth weights (i.e.,&amp;lt; 0.9 kg) for a given litter size is decreasing over time, and the critical birth weight level (below which lactation mortality increases strongly) is clearly population dependent and changes over time too.DiscussionThe increases in litter size and piglet survival rates due to balanced breeding policies lead to reduced total numbers of dead piglets (i.e., per country, per year) coinciding with a certain pig production volume (i.e., with a certain total number of weaned piglets).

Challenges and opportunities for improving nitrogen utilization efficiency for more sustainable pork production

Pork is one of the most consumed animal-derived protein sources around the world, but less than 45% of dietary nitrogen (N) is converted into edible lean meat. This inefficiency contributes to the 80% of human-induced N emissions that have resulted in exceeding the planetary boundaries for N. Reducing this inefficiency requires using a multifaceted approach. Swine genetic selection programs have improved the rate of lean growth in recent decades, but further improvements may be difficult because of lack of genetic variation within the global pig population. Breeding programs to increase litter size have led to intrauterine growth restriction and an increased proportion of low-birth-weight piglets which do not utilize dietary protein as efficiently as normal birth weight pigs. Intact males have greater lean growth rate and N efficiency than castrates and gilts, and the use of immunocastration technology has been implemented in some countries to capture this benefit while minimizing boar taint in pig meat. Use of other metabolic modifiers including porcine somatotropin and ractopamine, alone or in combination with immunocastration, can further enhance lean growth and dietary N efficiency, but a general lack of consumer acceptance and potential food safety concerns have led to regulatory restrictions in many countries. Because feed production contributes about 70% of N emissions in pig production systems, use of precision feed formulation and feeding practices, selected dietary feed additives, feed processing, and minimizing feed wastage appear to offer the greatest opportunity to reduce N waste and environmental footprint to improve the sustainability of pork production.

Review: Nutritional regulation of muscle growth in neonatal swine.

Despite advances in the nutritional support of low birth weight and early-weaned piglets, most experience reduced extrauterine growth performance. To further optimize nutritional support and develop targeted intervention strategies, the mechanisms that regulate the anabolic response to nutrition must be fully understood. Knowledge gained in these studies represents a valuable intersection of agriculture and biomedical research, as low birth weight and early-weaned piglets face many of the same morbidities as preterm and low birth weight infants, including extrauterine growth faltering and reduced lean growth. While the reasons for poor growth performance are multifaceted, recent studies have increased our understanding of the role of nutrition in the regulation of skeletal muscle growth in the piglet. The purpose of this review is to summarize the published literature surrounding advances in the current understanding of the anabolic signaling that occurs after a meal and how this response is developmentally regulated in the neonatal pig. It will focus on the regulation of protein synthesis, and especially the upstream and downstream effectors surrounding the master protein kinase, mechanistic target of rapamycin complex 1 (mTORC1) that controls translation initiation. It also will examine the regulatory pathways associated with the postprandial anabolic agents, insulin and specific amino acids, that are upstream of mTORC1 and lead to its activation. Lastly, the integration of upstream signaling cascades by mTORC1 leading to the activation of translation initiation factors that regulate protein synthesis will be discussed. This review concludes that anabolic signaling cascades are stimulated by both insulin and amino acids, especially leucine, through separate pathways upstream of mTORC1, and that these stimulatory pathways result in mTORC1 activation and subsequent activation of downstream effectors that regulate translation initiation Additionally, it is concluded that this anabolic response is unique to the skeletal muscle of the neonate, resulting from increased sensitivity to the rise in both insulin and amino acid after a meal. However, this response is dampened in skeletal muscle of the low birth weight pig, indicative of anabolic resistance. Elucidation of the pathways and regulatory mechanisms surrounding protein synthesis and lean growth allow for the development of potential targeted therapeutics and intervention strategies both in livestock production and neonatal care.

38 Effects of Dietary Supplementation with an Immuno-Modulator on Feed Intake and Reproductive Performance in Sows

Abstract OmniGen-AF (Phibro Animal Health, Teaneck, NJ; OG), an immuno-modulator consisting of a blend of vitamins, minerals, and microbial ingredients, has been employed in the dairy industry to mitigate the effects of heat stress and metabolic and immune system challenges on milk production. We previously reported that OG, fed to sows before and during lactation, decreased lactation BW loss, and increased litter birth and weaning weights (Lee et al., J. Anim. Sci. 99[Suppl. 3]:410-411, 2021). The objective of this study was to further these findings, by evaluating the effects of OG on feed intake and reproductive performance of crossbred sows. Berkshire x Duroc and Yorkshire x Landrace sows (n = 44; mean BW and parity, 276 kg and 4.6, respectively) from 10 farrowing groups and paired by parity and BW, were randomly assigned within pairs to one of two treatments: a fortified corn and soybean-meal based control diet (CON), or control diet top-dressed with 30 g of OG∙animal-1∙day-1. Sows consumed appropriate diets for approximately 35 d before expected farrowing date, throughout lactation, and the weaning to estrus interval. Sows were fed 2.7 kg∙animal-1∙day-1 during gestation, on an ad libitum basis during lactation, and 2.3 kg∙animal-1∙day-1 post-weaning. Total pigs born (12.3), pigs born alive (10.5), and pigs weaned (8.9) did not differ (P &amp;gt; 0.32) between treatments. Average birth weights, however, for both total pigs born (1.65 vs. 0.49 kg, SE = 0.11, P &amp;lt; 0.04) and pigs born alive (1.73 vs. 0.55 kg, SE = 0.11, P &amp;lt; 0.01) were greater for OG vs. CON sows. Pig BW at weaning were similar (P = 0.51) for OG (6.58 ± 0.25) and CON (6.34 ± 0.25). The ADFI during lactation tended to be greater (P = 0.09) for OG vs. CON sows (5.81 vs. 5.08 kg, SE = 0.29); however, total BW loss did not differ (P = 0.14) between treatments (10.0 and 5.2 kg, SE = 2.4 for OG and CON, respectively). The wean to estrus interval (5.1 d) was similar (P = 0.77) between groups. Under the conditions of this study, OG enhanced pig birth weights and sow feed consumption during lactation. The mechanisms responsible for these effects warrant further scrutiny.

Estimation of genetic parameters and inbreeding depression in Piau pig breed.

This study is aimed at estimating genetic parameters, effective population size, inbreeding, and inbreeding depression for birth weight, weaning weight, and average pre-weaning daily weight gain (ADG) in Piau pigs. We used information from 3841 Piau pigs, and four linear models were fitted in single-trait analyses, including or excluding maternal genetic effect, common litter effect, or a combination. The adjustments of the models were compared using the likelihood ratio test, in which the model that presented the best fit for each trait was used to estimate the (co)variance components. The inbreeding depression effect was evaluated using a linear model that included the fixed effects of sex, parity order, contemporary group, and inbreeding coefficient as a fixed covariate. The weights at birth and weaning showed low direct heritabilities (0.08 and 0.05, respectively), while the ADG showed moderate heritability (0.20). The weight at birth showed high genetic correlations with the weight at weaning (0.90) and the ADG (0.82). The weight at weaning and the ADG also showed a high genetic correlation (0.99). There was an inbreeding increase over the generations and a reduction in the effective population size. In the last generation evaluated, all the animals were inbred, the average inbreeding coefficient was 0.07, and the effective population size was 20.8. A significant inbreeding effect on ADG was observed, where an increase of 1% in the inbreeding coefficient resulted in a decrease of 0.005g in the ADG. Thus, increasing effective population size is mandatory for controlling inbreeding and reducing the loss of variability in this Piau pig population.

Sex bias in utero alters ovarian reserve but not uterine capacity in female offspring†.

Environmental stressors to which a fetus is exposed affect a range of physiological functions in postnatal offspring. We aimed to determine the in utero effect of steroid hormones on the reproductive potential of female offspring using a porcine model. Reproductive tracts of pigs from female-biased (>65% female, n = 15), non-biased (45-54.9% female, n = 15), and male-biased litters (<35% females, n = 9) were collected at slaughter (95-115kg). Ovaries and uterine horns were processed for H&E or immunohistochemistry. Variability of data within groups was analyzed with a Levene's test, while data were analyzed using mixed linear models in R. In the ovarian reserve, there was a significant birth weight by sex ratio interaction (P = 0.015), with low birth weight pigs from male-biased litters having higher numbers of primordial follicles with opposite trends seen in pigs from female-biased litters. Sex bias held no effect on endometrial gland development. A lower birth weight decreased the proportion of glands found in the endometrium (P = 0.045) and was more variable in both male-biased and female-biased litters (P = 0.026). The variability of primordial follicles from male-biased litters was greater than non- and female-biased litters (P = 0.014). Similarly, endometrial stromal nuclei had a greater range in male- and female-biased litters than non-biased litters (P = 0.028). A crucial finding was the greater variability in primordial follicles in the ovaries from females derived from male-biased litters and stromal cell count in the endometrium of females from male- and female-biased litters. This could be inflating the variability of reproductive success seen in females from male-biased litters.

Intrauterine growth retardation affects liver bile acid metabolism in growing pigs: effects associated with the changes of colonic bile acid derivatives

BackgroundIntrauterine growth retardation (IUGR) is associated with severely impaired nutrient metabolism and intestinal development of pigs. Our previous study found that IUGR altered intestinal microbiota and metabolites in the colon. However, the consequences of IUGR on bile acid metabolism in pigs remained unclear. The present study aimed to investigate the bile acid metabolism in the liver and the profile of bile acid derivatives in the colon of growing pigs with IUGR using bile acid targeted metabolomics. Furthermore, we determined correlations between colonic microbiota composition and metabolites of IUGR and normal birth weight (NBW) pigs at different growth stages that were 7, 21, and 28-day-old, and the average body weight (BW) of 25, 50, and 100 kg of the NBW pigs.ResultsThe results showed that the plasma total bile acid concentration was higher (P < 0.05) at the 25 kg BW stage and tended to increase (P = 0.08) at 28-day-old in IUGR pigs. The hepatic gene expressions related to bile acid synthesis (CYP7A1, CYP27A1, and NTCP) were up-regulated (P < 0.05), and the genes related to glucose and lipid metabolism (ATGL, HSL, and PC) were down-regulated (P < 0.05) at the 25 kg BW stage in IUGR pigs when compared with the NBW group. Targeted metabolomics analysis showed that 29 bile acids and related compounds were detected in the colon of pigs. The colonic concentrations of dehydrolithocholic acid and apocholic acid were increased (P < 0.05), while isodeoxycholic acid and 6,7-diketolithocholic acid were decreased (P < 0.05) in IUGR pigs, when compared with the NBW pigs at the 25 kg BW stage. Moreover, Spearman’s correlation analysis revealed that colonic Unclassified_[Mogibacteriaceae], Lachnospira, and Slackia abundances were negatively correlated (P < 0.05) with dehydrolithocholic acid, as well as the Unclassified_Clostridiaceae abundance with 6,7-diketolithocholic acid at the 25 kg BW stage.ConclusionsThese findings suggest that IUGR could affect bile acid and glucolipid metabolism in growing pigs, especially at the 25 kg BW stage, these effects being paralleled by a modification of bile acid derivatives concentrations in the colonic content. The plausible links between these modified parameters are discussed.

Short- and Long-Term Effects of Birth Weight and Neonatal Care in Pigs.

Swine industries worldwide face a loss in profit due to high piglet mortality, particularly as a consequence of the marked increase in prolificity and low birth weight (BW) of piglets. This research studied the effect of BW and individual neonatal care provided to piglets on preweaning mortality, and the long-term effects on growth and carcass and meat characteristics. Litters from seventy-one crossbred sows (PIC 34) were included in the trial. Half of each litter did not receive any further management, and the remaining half received the pre-established management protocol of early assistance of neonatal care (NC). Along lactation, the low-BW piglets (weight equal to or less than 1.1 kg) showed a threefold higher mortality rate than piglets of higher weights (32 vs. 10%; p = 0.001), with mortality particularly concentrated within the first week after birth. No effect of NC treatment was observed on mortality ratio caused by crushing, but a significant effect was observed in low-BW piglets who died of starvation (p &lt; 0.01). The effect of NC on growth is dependent on BW, and heavier piglets at birth benefit from NC treatment to a higher extent than low-BW piglets. Low-BW piglets showed a higher fatness (p = 0.003), lower lean cut yield (p = 0.002) in carcasses, and higher intramuscular fat (IMF) content (2.29% vs. 1.91%; p = 0.01) in meat. NC treatment increased the lean content in carcasses from low-BW piglets (p &lt; 0.01). The monounsaturated fatty acids concentration was higher in lower-than-normal-BW piglets (48.1% vs. 47.1%; p = 0.002) and the opposite effect was observed for polyunsaturated fatty acids (13.6% vs. 15.7%; p = 0.002). NC treatment induced a higher concentration of n-7 fatty acids. In conclusion, NC treatment may be a useful practice to reduce mortality in low-BW piglets. Moreover, NC could affect carcass fatness and meat quality, thus suggesting a long-term effect on metabolism.

268 Effect of Functional Amino Acid Supplementation in low and Normal Birth Weight Pigs on Performance and Immune Status During Subsequent Salmonella Challenge

Abstract Functional amino acid (FAA) supplementation improves growth performance and immune status of weaned pigs. The objective was to determine the effects of birth weight and FAA supplementation in the post-weaning period on the response of pigs to a subsequent Salmonella (ST) challenge. Thirty-two low (1.09±0.11 kg; LBW) and normal birth weight (1.58±0.11 kg; NBW) pigs were assigned to a nursery feeding program for 4 wk in a 2 × 2 factorial with factors of birth weight category (LBW vs. NBW) and basal (FAA–) or supplemented FAA profile (FAA+; Thr, Met, and Trp at 120% of requirements). Pigs were then placed onto a grower diet and, after a 7-d adaptation period, were inoculated with ST (2.2 × 109 CFU/mL) and monitored for 7 d post-inoculation. Growth performance, rectal temperature, gut health, ST fecal shedding and translocation, and blood parameters were measured pre- and post-inoculation. Inoculation with ST increased rectal temperature (39.7 vs. 38.9±0.5 oC) and overall rectal temperature was higher in LBW compared with NBW pigs (39.6 vs. 39.0±0.5 oC; P&amp;lt; 0.05). Salmonella shedding (1.8 vs. 2.3±0.1 score) and translocation to spleen (1.3 vs. 2.5±0.1 score) were less in NBW-FAA+ than NBW-FAA- pigs (P&amp;lt; 0.05). Post-inoculation weight gain was greater in NBW-FAA+ compared with the other groups (0.57 vs. 0.45±0.03 kg/d; P&amp;lt; 0.05). Post-inoculation haptoglobin (d 4; 1.0 vs. 0.7±0.1 g/L) and colonic myeloperoxidase (d 7; 4.3 vs. 2.5±0.6 µU/mL) were greater in LBW-FAA- pigs compared with the other groups (P&amp;lt; 0.05). On d 4 post-inoculation, plasma superoxide dismutase was less in LBW- FAA+ than in LBW-FAA- (60.5 vs. 93.3±7.7 mU/mL; P&amp;lt; 0.05). Reduced:oxidized glutathione at d 7 post-inoculation was greater in NBW compared with LBW pigs (2.5 vs. 1.7±0.3; P&amp;lt; 0.05). In conclusion, negative effects of Salmonella infection are ameliorated with supplementation of FAA to a greater extent in NBW than in LBW pigs.

Functional amino acid supplementation postweaning mitigates the response of normal birth weight more than for low birth weight pigs to a subsequent Salmonella challenge

Previous work has shown that dietary supplementation with key functional amino acids (FAA) improves growth performance and immune status of disease-challenged normal birth weight (NBW) pigs. It is not known whether FAA supplementation attenuates the effects of a subsequent disease challenge or whether this response is similar in low birth weight (LBW) pigs. The objective was to determine the effects of birth weight and FAA supplementation during the postweaning period in Salmonella-challenged pigs. Thirty-two LBW (1.08 ± 0.11 kg) and NBW (1.58 ± 0.11 kg) pigs were assigned to a nursery feeding program at weaning (25 d) for 31 days in a 2 × 2 factorial arrangement. Factors were birth weight category (LBW vs. NBW) and basal (FAA–) or supplemented FAA profile (FAA+; Thr, Met, and Trp at 120% of requirements). At d 31, pigs were placed onto a common grower diet and, after a 7-d adaptation period, were inoculated with Salmonella Typhimurium (ST; 2.2 × 109 colony-forming units/mL) and monitored for 7-d postinoculation. Growth performance, rectal temperature, fecal score, indicators of gut health, ST shedding score in feces, intestinal ST colonization and translocation, and blood parameters of acute-phase response and antioxidant balance were measured pre- and postinoculation. Inoculation with ST increased temperature and fecal score, and the overall rectal temperature was higher in LBW compared to NBW pigs (P < 0.05). Postinoculation (d 7), reduced:oxidized glutathione was increased in NBW compared to LBW pigs (P < 0.05). Salmonella shedding and translocation to spleen were lower in NBW-FAA+ compared to NBW-FAA− pigs (P < 0.05). Postinoculation average daily gain was higher in NBW-FAA+ (P < 0.05) compared to the other groups. Postinoculation haptoglobin, superoxide dismutase, and colonic myeloperoxidase were increased in LBW-FAA− pigs (P < 0.05). Ileal alkaline phosphatase was decreased in LBW compared to NBW (P < 0.05). Overall, FAA supplementation represents a potential strategy to mitigate the effect of enteric disease challenge in NBW, but not LBW pigs.