Litter Size Research Articles

Superovulation with an anti-inhibin monoclonal antibody improves the reproductive performance of rat strains by increasing the pregnancy rate and the litter size

Rats are multiparous rodents that have been used extensively in research; however, the low reproductive performance of some rat strains hampers the broader use of rats as a biomedical model. In this study, the possibility of increasing the litter size after natural mating in rats through superovulation using an anti-inhibin monoclonal antibody (AIMA) was examined. In outbred Wistar rats, AIMA increased the number of ovulated oocytes by 1.3-fold. AIMA did not affect fertilization and subsequent embryonic development, resulting in a 1.4-fold increase in litter size and a high pregnancy rate (86%). In contrast, conventional superovulation by eCG/hCG administration decreased the pregnancy rate to 6–40% and did not increase the litter size. In inbred Brown Norway rats, AIMA increased the litter size by 1.2-fold, and the pregnancy rate increased more than twice (86% versus 38% in controls). AIMA also increased the litter size by 1.5-fold in inbred Tokai High Avoiders and Fischer 344 rats. AIMA increased the efficiency of offspring production by 1.5-, 2.7-, 1.4-, and 1.4-fold, respectively, in the four rat strains. Thus, AIMA may consistently improve the reproductive performance through natural mating in rats, which could promote the use of AIMA in biomedical research.

The mammalian sperm factor phospholipase C zeta is critical for early embryo division and pregnancy in humans and mice.

The mammalian sperm factor phospholipase C zeta is critical for early embryo division and pregnancy in humans and mice.

Assessing reproductive performance and predictive models for litter size in Landrace sows under tropical conditions.

Litter size and piglet loss at birth significantly impact piglet production and are closely associated with sow parity. Understanding how these traits vary across different parities is crucial for effective herd management. This study investigates the patterns of the number of born alive piglets (NBA), number of piglet losses (NPL), and the proportion of piglet losses (PPL) at birth in Landrace sows under tropical conditions. Additionally, it aims to identify the most suitable model for describing these patterns. A dataset comprising 2,322 consecutive reproductive records from 258 Landrace sows, spanning parities from 1 to 9, was analyzed. Modeling approaches including 2nd and 3rd degree polynomial models, the Wood gamma function, and a longitudinal model were applied at the individual level to predict NBA, NPL, and PPL. The choice of the best-fitting model was determined based on the lowest mean and standard deviation of the difference between predicted and actual values, Akaike information criterion (AIC), and Bayesian information criterion (BIC). Sow parity significantly influenced NBA, NPL, and PPL (p<0.0001). NBA increased until the 4th parity and then declined. In contrast, NPL and PPL decreased until the 2nd parity and then steadily increased until the 8th parity. The 2nd and 3rd degree polynomials, and longitudinal models showed no significant differences in predicting NBA, NPL, and PPL (p>0.05). The 3rd degree polynomial model had the lowest prediction standard deviation and yielded the smallest AIC and BIC. The 3rd degree polynomial model offers the most suitable description of NBA, NPL, and PPL patterns. It holds promise for applications in genetic evaluations to enhance litter size and reduce piglet loss at birth in sows. These findings highlight the importance of accounting for sow parity effects in swine breeding programs, particularly in tropical conditions, to optimize piglet production and sow performance.

The transgenerational effects of maternal low-protein diet during lactation on offspring

Environmental factors such as diet and lifestyle can influence the health of both mothers and offspring. However, its transgenerational transmission and underlying mechanisms remain largely unknown. Here, using a maternal lactation-period low-protein diet (LPD) mouse model, we show that maternal LPD during lactation causes decreased survival and stunted growth, significantly reduces ovulation and litter size, and alters the gut microbiome in the female LPD-F1 offspring. The transcriptome of LPD-F1 metaphase II (MII) oocytes shows that differentially expressed genes are enriched in female pregnancy and multiple metabolic processes. Moreover, maternal LPD causes early stunted growth and impairs metabolic health, which is transmitted over two generations. The methylome alteration of LPD-F1 oocytes can be partly transmitted to the F2 oocytes. Together, our results reveal that LPD during lactation transgenerationally affects offspring health, probably via oocyte epigenetic changes.

Association of polymorphism in the promotor area of the caprine BMPR1B gene with litter size and body measurement traits in Damani goats.

This study aimed to explore polymorphisms in the promoter region of the caprine BMPR1B (Bone morphogenetic protein receptor 1 beta) gene and its association with body measurement and litter size traits in Damani does. A total of 53 blood samples were collected to analyze the association between the BMPR1B gene polymorphism and 11 phenotypic traits in Damani female goats. The results revealed that three novel SNPs were identified in the promoter region of the caprine BMPR1B gene, including g.67 A > C (SNP1), g.170 G > A(SNP2), and g.501A > T (SNP3), among which the SNP1 and SNP2 were significantly (p < 0.05) associated with litter size and body measurement traits in Damani goats. In SNP1 the AC genotype could be used as a marker for litter size, and the CC genotype for body weight in Damani goats. In SNP2, the genotype GG was significantly (p < 0.05) associated with ear and head length. Therefore, we can conclude from the present study, that genetic variants AC and CC of the caprine BMPR1B gene could be used as genetic markers for economic traits through marker-assisted selection for the breed improvement program of the Damani goat.

Key mRNAs and lncRNAs of pituitary that affect the reproduction of FecB + + small tail han sheep

BackgroundThe pituitary directly regulates the reproductive process through follicle-stimulating hormone (FSH) and luteinizing hormone (LH). Transcriptomic research on the pituitaries of ewes with different FecB (fecundity Booroola) genotypes has shown that some key genes and lncRNAs play an important role in pituitary function and sheep fecundity. Our previous study found that ewes with FecB + + genotypes (without FecB mutation) still had individuals with more than one offspring per birth. It is hoped to analyze this phenomenon from the perspective of the pituitary transcriptome.ResultsThe 12 Small Tail Han Sheep were equally divided into polytocous sheep in the follicular phase (PF), polytocous sheep in the luteal phase (PL), monotocous sheep in the follicular phase (MF), and monotocous sheep in the luteal phase (ML). Pituitary tissues were collected after estrus synchronous treatment for transcriptomic analysis. A total of 384 differentially expressed genes (DEGs) (182 in PF vs. MF and 202 in PL vs. ML) and 844 differentially expressed lncRNAs (DELs) (427 in PF vs. MF and 417 in PL vs. ML) were obtained from the polytocous-monotocous comparison groups in the two phases. Functional enrichment analysis showed that the DEGs in the two phases were enriched in signaling pathways known to play an important role in sheep fecundity, such as calcium ion binding and cAMP signaling pathways. A total of 1322 target relationship pairs (551 pairs in PF vs. MF and 771 pairs in PL vs. ML) were obtained for the target genes prediction of DELs, of which 29 DEL-DEG target relationship pairs (nine pairs in PF vs. MF and twenty pairs in PL vs. ML). In addition, the competing endogenous RNA (ceRNA) networks were constructed to explore the regulatory relationships of DEGs, and some important regulatory relationship pairs were obtained.ConclusionAccording to the analysis results, we hypothesized that the pituitary first receives steroid hormone signals from the ovary and uterus and that VAV3 (Vav Guanine Nucleotide Exchange Factor 3), GABRG1 (Gamma-Aminobutyric Acid A Receptor, Gamma 1), and FNDC1 (Fibronectin Type III Domain Containing 1) played an important role in this process. Subsequently, the reproductive process was regulated by gonadotropins, and IGFBP1 (Insulin-like Growth Factor Binding Protein 1) was directly involved in this process, ultimately affecting litter size. In addition, TGIF1 (Transforming Growth Factor-Beta-Induced Factor 1) and TMEFF2 (Transmembrane Protein With EGF Like And Two Follistatin Like Domains 2) compensated for the effect of the FecB mutation and function by acting on TGF-β/SMAD signaling pathway, an important pathway for sheep reproduction. These results provided a reference for understanding the mechanism of multiple births in Small Tail Han Sheep without FecB mutation.

Effects of artificial rearing on behaviour, welfare, and immune function in piglets

With the steady increase in litter sizes, artificial rearing is becoming widely used to raise surplus piglets. The study aimed to evaluate the potential impacts of artificial rearing on behaviour and immune function in piglets. A total of 240 piglets were divided into three groups: piglets reared by the sow until weaning on day 35 (CON group), piglets artificially reared from day 7 (AR7 group), and piglets artificially reared from day 21 (AR21 group). Behavioural observation was conducted for 8 hours weekly, and the elimination position was recorded on days 7, 21, and 35. Serum and hair samples were collected to measure immunoglobulins and cortisol concentration, respectively. The results revealed that piglets in the AR7 group exhibited less frequent milk-drinking, exploring, and playing, but more frequent belly nosing and oral manipulation of conspecifics. Moreover, artificial rearing affected the elimination sites of AR7 piglets on day 21, but this phenomenon was not observed on day 35. In addition, the AR7 piglets had higher levels of cortisol and CRP, as well as lower levels of IgG and IgA compared to the CON piglets. The AR21 piglets also had a higher CRP level compared to the CON piglets. In conclusion, artificial rearing, initiated either from day 21 or day 7, negatively affected behavioural expression and immune function. Artificial rearing from day 7 was found to be the most physiologically detrimental.

Increased uterine arterial tone, stiffness and remodeling with augmented matrix metalloproteinase-1 and -7 in uteroplacental ischemia-induced hypertensive pregnancy

Preeclampsia is a pregnancy-related disorder manifested as hypertensive pregnancy (HTN-Preg) and often fetal growth restriction (FGR), but the mechanisms involved are unclear. We have reported enhanced reactivity of systemic vessels in HTN-Preg rats, but the critical changes in the uterine circulation are less clear. We tested whether HTN-Preg involves localized aberrations in uterine arterial tone, stiffness and remodeling by matrix metalloproteinases (MMPs). Blood pressure (BP) and litter size were recorded in normal pregnant (Preg) rats and Preg rats with reduced uteroplacental perfusion pressure (RUPP). Isolated uterine arteries were placed in a pressure myograph for measuring intrinsic and extrinsic tone and arterial stiffness. Arteries were bathed in normal Krebs solution (2.5 mM Ca2+), Ca2+-free (2 mM EGTA) Krebs, treated with sodium nitroprusside (SNP), or endothelium denuded, then pressurized at 10 mmHg steps from 10 to 110 mmHg, and the % change in diameter was analyzed to measure total (active + passive), active Ca2+-dependent myogenic, passive, and endothelium-dependent tone, respectively. BP was higher and the litter size and pup weight were reduced in RUPP vs Preg rats. In normal Krebs, increasing intraluminal pressure caused smaller increments in diameter in arteries of RUPP vs Preg rats, suggesting greater total vascular tone. Arterial incubation in Ca2+-free Krebs, treatment with SNP or endothelium-removal abolished the differences in vascular tone, and subtraction of each of these components from total vascular tone revealed significant active Ca2+-dependent myogenic, passive, and endothelium-dependent tone, respectively, in RUPP vs Preg rats. The total and passive strain–stress curves were shifted leftward in arteries of RUPP vs Preg rats, indicating increased uterine arterial stiffness. Arterial sections showed decreased lumen/total and increased wall/total area, and immunohistochemistry revealed greater MMP-1 and MMP-7 staining particularly in the media, suggesting uterine arterial remodeling by MMPs in RUPP vs Preg rats. The increased uterine arterial active myogenic, passive, and endothelium-dependent tone, arterial stiffness and remodeling by MMPs would further reduce uterine blood flow and exacerbate uteroplacental ischemia, FGR and HTN-Preg.

Effects of short and long – term nutrition and progesterone supplementation on the success of fixed – time artificial insemination in the ewe

The success of fixed - time artificial insemination (AI) in the ewe is variable due to poor synchrony of estrus. We examined the effects of long-term nutrition (LTN; low, medium, high - 6 months), short-term nutrition (STN; 1.0 M, 1.5 M – 14 days) and progesterone supplementation (P; single pessary, replacement on Day 9) on synchrony and reproductive outcomes. High LTN advanced (P < 0.05) estrus, increased (P = 0.06) pregnancy (range 71.1 – 81.1%) and improved (P < 0.01) litter size (range 1.30 – 1.50). STN increased (P < 0.05) pregnancy (79.0 versus 72.3%) but not litter size or timing of estrus. A LTN x STN interaction (P < 0.01) for time of estrus indicates that the effects of LTN were moderated by STN depending on the level of LTN. Pessary replacement delayed (P < 0.05) the onset of estrus, improved synchrony but did not affect pregnancy or litter size. High LTN increased (P < 0.05) the number of large (≥ 3.8 mm) and medium - size follicles (2.0 – 3.7 mm) but the diameter of large follicles tended to be reduced (P = 0.08) on Day 12. STN did not affect follicle number or size whilst P reduced (P < 0.05) the diameter of large follicles on Day 12 (4.83 versus 5.10 mm) and increased the number of medium – size follicles (3.56 versus 2.74 mm). In conclusion, both LTN and STN are major sources of variability in AI programs whilst pessary replacement has potential to reduce variability.

Reproductive performance of local goats in Municipality of Liquica

One of the small ruminants with a lot of promise and popularity in the Municipality of Liquica are kacang goats. The purpose of this study is to determine how well the local goats in Liquica Municipality reproduce. In this study, a quantitative approach was taken. The research location was chosen using the purposive sampling method. The criterion of having at least three goats and five years of experience with them were used to choose the responders for this study. Solvin's formula was employed to ascertain the sample size. The variables that were observed were the kidding interval, size of the litter, length of pregnancy, and age at puberty. The findings demonstrated that the local goats in Tibar Village had good reproductive performance. Of the 71 respondents, they reported that the average age at puberty was 6.51 ± 0.65, the average gestation period was 5.08 ± 0.28, the average litter size was 1.08 ± 0.36, and the average calving interval was 8.86±0.59. Ulmera Village respondents, numbering seventy, stated that the local goats' puberty age was 7.84 ± 0.93, their gestation period was 5.09 ± 0.28, their litter size was 1.6 ± 0.48, and their calving interval was 8.56 ± 0.53. In Liquisa Municipality, the reproductive performance of Javanese goats is deemed satisfactory despite farmers' continued adherence to customary rearing practices.

Comparative Study on the Use of Artificial Insemination in Sows in Three Production Units in the Region of Tlachichuca Puebla, México

The main objective of this study was to make a comparison of the use of artificial insemination in sows from three production units belonging to the Tlachichuca-Puebla region, Mexico. These pork production units belonged to the communities of José María Morelos, San Francisco Independencia and Tlachichuca, Puebla respectively. 20 sows were used, 15 of which were primal and 5 multiparous, which were inseminated over a period of 10 months. 20 doses of semen were acquired from the Coyametl Genetic Transfer Center, located in the City of Acatzingo, Puebla. The information obtained from the project was concentrated in the different stages of the study, and stored in an Excel file; the information was processed through the SPSS 10 package for Windows, applying descriptive statistics. 75% of Primal or Nulliparous sows were found which were artificially inseminated and 25% corresponded to Multiparous; 7% of the producers expressed no interest in planning but rather a greater number of kilos when selling, 15% responded interest in the number of offspring and fewer deaths at birth with better feeding of the bellies before and after the births, 78% mentioned the importance of planning a procedure to improve their productivity and reproductive life in their pork production units (PPUs). Regarding litter size, results were obtained through AI in the sows of the 3 UPPs (José María Morelos, San Francisco Independencia and Tlachichuca), a total of piglets in the primals of 163 of the 15 inseminated sows, with an average of 10.8 piglets/sow; In the case of multiparous sows, there were 58 piglets in total with an average of 11.6 piglets/sow. In conclusion, comparative studies are useful for analysis in pork production units, since they are pillars in decision making; as it was, in the reproductive indicators where AI was applied, giving objectivity and greater certainty as was the case in the three communities of the Tlachichuca region, Puebla, Mexico.

Use of a precision feeding program during gestation improves the performance of high-producing sows

Current gestating sow feeding strategies are based on using a single diet regardless of parity or gestation stage. Precision feeding (PF) of the individual sows allows dynamic changes in amino acid and energy requirements throughout gestation. The hypothesis of the study was that meeting the daily predicted amino acid and energy demands of gestating sows using a mathematical model and automatic precision feeder to establish the nutrition programs, would improve reproductive and productive performance compared to conventional feeding programs. Seventy-five mixed-parity sows were distributed among 3 treatments. A treatment managed as flat curve (FLAT: 2.1 kg/d, 1 – 110 d), a high-low-high curve (HLH: 2.2 kg/d, 1 – 49 d; 2.0 kg/d, 50 – 84 d; 2.6 kg/d, 85 – 110 d), where sows received the same diet with 3.2 Mcal/kg of metabolizable energy (ME) and 0.7 g/kg of standardized ileal digestible (SID) lysine. For the PF treatment, feeding level and blend of 2 basal diets (3.0 Mcal/kg of ME; 8.0 and 2.0 g/kg of SID lysine for high and low lysine, respectively) was adjusted daily for each sow to accurately meet estimated amino acid and energy requirements based on live weight, gestation stage and parity. Sows fed PF were heavier on d 110 of gestation (P = 0.011) and tended to increase total number of born (P = 0.092) and born alive (P = 0.077). Sows fed PF showed a higher litter weight (P = 0.003) at birth, lower lactation feed intake (P = 0.010), higher milk yield (P = 0.043) and a larger litter size (P = 0.050). Precision feeding sows also presented an improved maternal transformation index (P = 0.013) when compared to HLH and FLAT. In conclusion, our results demonstrate that the application of PF strategies based on daily nutrient adjustments is highly beneficial for high-producing sows to support the dynamic needs for nutrient availability for the sow´s body growth, mammary gland and fetal development.

Association analysis of polymorphisms in SLK, ARHGEF9, WWC2, GAB3, and FSHR genes with reproductive traits in different sheep breeds.

The aim was to investigate the relationship between polymorphisms of gene mutation loci and reproductive traits in local sheep breeds (Duolang Sheep) and introduced sheep breeds (Suffolk, Hu Sheep) in Xinjiang to provide new molecular markers for the selection and breeding of high fecundity sheep. The expression pattern of typing successful genes in sheep tissues was investigated by RT-qPCR technology, providing primary data for subsequent verification of gene function. The 26 mutation loci of WWC2, ARHGEF9, SLK, GAB3, and FSHR genes were typed using KASP. Association analyses were performed using SPSS 25.0, and the typing results showed that five genes with six loci, WWC2 (g.14962207 C>T), ARHGEF9 (g.48271079 C>A), SLK (g.27107842 T>C, g.27108855 G>A), GAB3 (g.86134602 G>A), and FSHR (g.80789180 T>G) were successfully typed. The results of the association analyses showed that WWC2 (g.14962207 C>T), SLK (g.27108855 G>A), ARHGEF9 (g.48271079 C>A), and FSHR (g.80789180 T>G) caused significant or extremely significant effects on the litter size in Duolang, Suffolk and Hu Sheep populations. The expression distribution pattern of the five genes in 12 sheep reproduction-related tissues was examined by RT-qPCR. The results showed that the expression of the SLK gene in the uterus, the FSHR gene in the ovary, and the ARHGEF9 gene in hypothalamic-pituitary-gonadal axis-related tissues were significantly higher than in the tissues of other parts of the sheep. WWC2 and GAB3 genes were highly expressed both in reproductive organs and visceral tissues. In summary, the WWC2 (g.14962207 C>T), SLK (g.27108855 G>A), ARHGEF9 (g.48271079 C>A), and FSHR (g.80789180 T>G) loci can be used as potential molecular markers for detecting differences in reproductive performance in sheep. Due to variations in typing results, the SLK (g.27107842 T>C) and GAB3 (g.86134602 G>A) loci need further validation.

Polymorphisms of the HRG, FETUB, and GUCY1A1 genes and their association with litter size in sheep

Abstract. Litter size is one of the key factors affecting the efficiency of sheep breeding, and previous studies found that the HRG, FETUB, and GUCY1A1 genes were closely related to litter size in sheep. This experiment aims to explore the polymorphisms of the g.405442728A&gt;G locus of the HRG gene, the g.421655951C&gt;T locus of the FETUB gene, and the g.414050897G&gt;C locus of the GUCY1A1 gene and their association with sheep litter size. The MassARRAY® single-nucleotide polymorphism (SNP) genotyping technique was used to detect the polymorphisms of these loci in five sheep breeds, i.e., Small-tailed Han sheep, Hu sheep, Cele black sheep, Sunite sheep, and Bamei mutton sheep. In addition, the association between the polymorphisms of these genes and the litter size of Small-tailed Han sheep was also analyzed. The results showed that the g.405442728A&gt;G locus of the HRG gene was moderately polymorphic (0.25 &lt; PIC &lt;0.5) in both monotocous and polytocous sheep breeds; the g.421655951C&gt;T locus of the FETUB gene was lowly polymorphic (PIC &lt;0.25) in five sheep breeds; the g.414050897G&gt;C locus of GUCY1A1 showed moderately polymorphism in Small-tailed Han sheep (0.25 ≤ PIC &lt;0.5) and low polymorphism in four other sheep breeds (PIC &lt;0.25). The chi-squared test results showed that the g.405442728A&gt;G locus of the HRG gene was in the Hardy–Weinberg equilibrium state in five sheep breeds (P&gt;0.05). The g.421655951 C&gt;T locus of the FETUB gene and the g.414050897G&gt;C locus of the GUCY1A1 gene were in the Hardy–Weinberg equilibrium state in Small-tailed Han sheep (P&gt;0.05) and in the Hardy–Weinberg disequilibrium state in other sheep breeds (P&lt;0.05). The association analysis showed that the g.405442728A&gt;G locus of the HRG gene and the g.421655951C&gt;T locus of the FETUB gene had a significant impact on the litter size of sheep (P&lt;0.05), while the g.414050897G&gt;C locus of the GUCY1A1 gene had no significant impact on the litter size (P&gt;0.05). In summary, the HRG gene and the FETUB gene can be used as potential molecular markers for the selection of the litter size in sheep.

Responses of selected plasma metabolites to a 2-day nutritional challenge of goats divergently selected for functional longevity

Understanding the extent to which genetics × environment plays a role in shaping individual strategies to environmental challenges is of considerable interest for future selection of more resilient animals. Accordingly, the objective of this study was to evaluate the metabolic responses to a nutritional challenge of goats divergently selected for functional longevity based on plasma metabolites and the repeatability of these responses across 2 experimental farms and years. We carried out 6 different experimental trials from years 2018 to 2022 (4 trials on site Bourges (2018-21) and 2 trials (2021-22) on site Grignon) in which 267 first kidding goats, daughters of Alpine bucks divergently selected for functional longevity, longevity plus (n = 137), and longevity minus (n = 130), were exposed to a 2-d nutritional challenge in early lactation. The experiments consisted of a 5 or 7-d control period (pre-challenge) on a standard lactation diet followed by a 2-d nutritional challenge with straw-only feeding and then a 7 or 10-d recovery period on a standard lactation diet, for site Bourges and Grignon, respectively. During the challenge plasma metabolite composition was recorded daily. Linear mixed-effects models were used to analyze all traits, considering the individual as a random effect and the 2x2 treatments (i.e., genetic line and year nested in site) and litter size as fixed effects. The linear mixed-effects model using a piecewise arrangement was used to analyze the response/recovery profiles to the nutritional challenge. Random parameters estimated for each individual, using the mixed-effects models without the fixed effects of genetic line, were used in a Sparse Partial Least Square Discriminant Analysis (sPLS-DA) to compare the goat metabolism response to the challenge on a multivariate scale. The plasma metabolites, glucose, β-hydroxybutyrate (BHB), and nonesterified fatty acids (NEFA), and urea concentrations responded to the 2-d nutritional challenge. Selection for functional longevity did not affect plasma glucose, NEFA, BHB, and urea response/recoveries to a 2-d nutritional challenge. However, site, trial, and litter size affected these responses. Moreover, the plasma metabolites seem not to fully recover to prechallenge levels after the recovery phase. The sPLS-DA analysis did not discriminate between the 2 longevity lines. We observed meaningful between-individuals' variability in plasma BHB, especially on the prechallenge and rate of response and rate of recovery from the 2-d nutritional challenge (CV = 26.2%, 36.1%, and 41.2%, repeatability = 0.749, 0.322, and 0.741, respectively). Plasma NEFA recovery from challenge also demonstrated high between-individuals' variability (CV = 16.4%, repeatability = 0.323). Selection for functional longevity did not affect plasma metabolites responses to a 2-d nutritional challenge in dairy goats. Plasma NEFA and BHB response/recovery presented high between-individuals' variability, indicating individual adaptative characteristics to nutritional challenges not related to the environmental conditions but to inherent individual characteristics.

Genetic variant of the sheep E2F8 gene and its associations with litter size

The economic efficiency of sheep breeding, aiming to enhance productivity, is a focal point for improvement of sheep breeding. Recent studies highlight the involvement of the Early Region 2 Binding Factor transcription factor 8 (E2F8) gene in female reproduction. Our group’s recent genome-wide association study (GWAS) emphasizes the potential impact of the E2F8 gene on prolificacy traits in Australian White sheep (AUW). Herein, the purpose of this study was to assess the correlation of the E2F8 gene with litter size in AUW sheep breed. This work encompassed 659 AUW sheep, subject to genotyping through PCR-based genotyping technology. Furthermore, the results of PCR-based genotyping showed significant associations between the P1-del-32bp bp InDel and the fourth and fifth parities litter size in AUW sheep; the litter size of those with genotype ID were superior compared to those with DD and II genotypes. Thus, these results indicate that the P1-del-32bp InDel within the E2F8 gene can be useful in marker-assisted selection (MAS) in sheep.

Effects of Growth Hormone-Releasing Hormone (GHRH) Plasmid Treatment on the Reproductive Productivity of Sows in Primiparous and Multiparous Sow Breeds.

The effect of growth hormone-releasing hormone (GHRH) plasmid treatment on sow reproductive performance was examined. Forty pregnant sows (three-way crossbreed: Landrace × Yorkshire × Duroc) at 85 days of gestation were included in the study and consisted of twenty primiparous and twenty multiparous sows (third parity). Sows were randomly assigned to the control and treatment groups. The treatment group received 5 mg dose of GHRH plasmid injection via electroporation, whereas the control group received a phosphate buffer solution. Reproductive indicators, including serum insulin-like growth factor-1 (IGF-1) concentration and weaned piglet data, were assessed. In the GHRH plasmid-treated group, serum IGF-1 concentration significantly increased compared with that in the control group, a trend observed in primiparous and multiparous sows. The key indicator of reproductive performance, litter size, showed that for control primiparous sows (C-PS), it was 10.90 ± 0.99 kg, while for control multiparous sows (C-MS), it was 14.00 ± 0.67 kg. Furthermore, for primiparous sows treated with GHRH plasmid (G-PS), the litter size was 11.60 ± 0.97 kg, and for multiparous sows treated with GHRH plasmid (G-MS), it was 14.00 ± 0.82 kg. The GHRH plasmid-treated group also exhibited a higher number of total births and surviving piglet numbers, along with a decrease in stillborn piglets; however, there was no significant difference in birth weight. The results suggest that GHRH plasmid treatment can enhance the reproductive performance of sows.

Increased miR-3074-5p expression promotes M1 polarization and pyroptosis of macrophages via ERα/NLRP3 pathway and induces adverse pregnancy outcomes in mice

Decidual macrophages (dMϕs) play critical roles in regulation of immune-microhomeostasis at maternal-fetal interface during pregnancy, but the underlying molecular mechanisms are still unclear. In this study, it was found that litter size and fetal weight were significantly reduced, whereas the rate of embryo resorption was increased in miR-3074-5p knock-in (3074-KI) pregnant mice, compared to that of wild-type (WT) pregnant mice. Plasma levels of pro-inflammatory cytokines in 3074-KI pregnant mice were also significantly elevated compared to WT pregnant mice at GD7.5. The quantity of M1-Mϕs in uterine tissues of 3074-KI pregnant mice was significantly increased compared to WT pregnant mice at GD13.5. Estrogen receptor-α (ERα) was validated to be a target of miR-3074-5p. Either miR-3074-5p overexpression or ERα knockdown promoted transcriptional activity of NF-κB/p65, induced M1-polarization and pyroptosis of THP1-derived Mϕs, accompanied with increased intracellular levels of cleaved Caspase-1, cleaved IL-1β, NLRP3, cleaved GSDMD and ASC aggregation. Furthermore, ERα could not only bind to NLRP3 or ASC directly, but also inhibit the interaction between NLRP3 and ASC. The endometrial miR-3074-5p expression level at the middle secretory stage of repeated implantation failure (RIF) patients was significantly decreased compared to that of control fertile women. These data indicated that miR-3074-5p could promote M1 polarization and pyroptosis of Mϕs via activation of NLRP3 inflammasome by targeting ERα, and the dysregulation of miR-3074-5p expression in dMϕs might damage the embryo implantation and placentation by interfering with inflammatory microenvironment at the maternal-fetal interface during early pregnancy.

Testing the Adaptive Sterilization Hypothesis in mice inoculated with Chlamydia muridarum.

The "adaptive sterilization hypothesis" argues that the tendency of sexually transmitted infections (STIs) to cause infertility likely reflects an evolutionary adaptation of these pathogens. For example, some STIs can lead to bilateral occlusions of the oviducts and sterile matings. Cycling females that do not spend time gestating and lactating are ready to mate sooner than fertile females, and therefore, likely to mate more frequently and possibly more promiscuously. These sexual activities are associated with enhanced transmissibility of STIs, and tubal occlusion is a proximate mechanism by which STIs can increase fitness. Our principal objectives were to determine whether female mice inoculated with Chlamydia muridarum mate more frequently than mice inoculated with sterile saline and to test the hypothesis that tubal occlusion following C. muridarum infection modulates mating behavior in a manner that might increase transmissibility of Chlamydia. Similar to C. trachomatis infections in human females, C. muridarum can ascend the reproductive tract of mice, damage and occlude the oviducts, and cause infertility. However, ovarian function and mating activity are maintained following tubal occlusion. Twenty C57Bl/6 mice with regular estrous cycles were given intra-vaginal inocula of C. muridarum and 32 days later paired with a male for 90 days. Nine saline-treated females served as controls. Three Chlamydia-inoculated females were rendered infertile due to bilateral oviductal damage and mated 8 (±0.0) times. Control females mated on average 4.6 (±0.3) times, and 17 Chlamydia-inoculated fertile females, including six females with only a single oviduct occluded, mated on average 4.7 (±0.2) times. Chlamydia-inoculated fertile females with unilateral oviductal damage had significantly smaller average litter sizes as compared to females inoculated with saline. Females with unilateral tubal occlusion also tended to wean fewer pups than saline controls over the course of 90 days. Female mice with Chlamydia-induced tubal infertility mated more frequently (approximately every 11 d) than did fertile females (approximately every 20 d), which is consistent with the adaptive sterilization hypothesis. To determine whether Chlamydia-induced sterilization is truly adaptive, future studies will need to demonstrate increased sexual transmissibility, and possibly increased promiscuity, within populations of freely breeding mice.

Life-history of masked water snakes (Homalopsis buccata) in Java: implications for the sustainability of harvesting

Context Masked water snakes (Homalopsis buccata, Homalopsidae) thrive in the muddy edges of agricultural ponds and canals in densely populated areas of West Java, Indonesia, and are harvested by local farmers to protect fish stocks and to provide meat, skins, and medicines for commercial use. Aims Here, we aimed to quantify sexual dimorphism and reproductive biology of H. buccata, so as to deepen our knowledge of the species’ inherent ability to withstand commercial harvests. Methods We examined carcasses of 4286 snakes at six processing sites to quantify biological attributes (e.g. sexual dimorphism in body size and shape, seasonality of reproduction, fecundity, reproductive frequency), with emphasis on traits that affect the ability of snake populations to withstand this intensive harvesting. Key results The snakes we examined were primarily adults (&lt;1% juvenile), with approximately equal numbers of males and females except in January (when females comprised &gt;90% of specimens). Females grow larger than males, and they are more heavy-bodied but shorter-tailed than are males of the same snout–vent length. Reproduction is seasonal in both sexes, with testis volumes decreasing to a minimum over the period August to November (late dry season) when most adult-size females were gravid. Litter sizes ranged from 1 to 37 (mean 12), increasing with maternal body size, with ~75% of females reproducing each year. Conclusions On the basis of these results, we infer that the life history of H. buccata (viviparity, high fecundity, frequent reproduction, rapid maturation) renders it inherently resilient to harvesting, especially because that offtake is based on males as well as females. Because a lack of sustainability is evident only in hindsight, regular monitoring of the trade could assure that any problems are detected rapidly. Implications To further buffer these populations from the impact of harvest, hunting could be restricted during January (a time when gravid females are disproportionately vulnerable) and the largest snakes (females, with high fecundity and reproductive frequency) could be excluded from harvests.