Reduced Litter Size Research Articles

HENMT1 is involved in the maintenance of normal female fertility in the mouse.

PIWI-interacting small RNAs (piRNAs) maintain genome stability in animal germ cells, with a predominant role in silencing transposable elements. Mutations in the piRNA pathway in the mouse uniformly lead to failed spermatogenesis and male sterility. By contrast, mutant females are fertile. In keeping with this paradigm, we previously reported male sterility and female fertility associated with loss of the enzyme HENMT1, which is responsible for stabilising piRNAs through the catalysation of 3'-terminal 2'-O-methylation. However, the Henmt1 mutant females were poor breeders, suggesting they could be subfertile. Therefore, we investigated oogenesis and female fertility in these mice in greater detail. Here, we show that mutant females indeed have a 3- to 4-fold reduction in follicle number and reduced litter sizes. In addition, meiosis-II mutant oocytes display various spindle abnormalities and have a dramatically altered transcriptome which includes a down-regulation of transcripts required for microtubule function. This down-regulation could explain the spindle defects observed with consequent reductions in litter size. We suggest these various effects on oogenesis could be exacerbated by asynapsis, an apparently universal feature of piRNA mutants of both sexes. Our findings reveal that loss of the piRNA pathway in females has significant functional consequences.

Uterine kisspeptin receptor critically regulates epithelial estrogen receptor α transcriptional activity at the time of embryo implantation in a mouse model.

Embryo implantation failure is a major cause of infertility in women of reproductive age and a better understanding of uterine factors that regulate implantation is required for developing effective treatments for female infertility. This study investigated the role of the uterine kisspeptin receptor (KISS1R) in the molecular regulation of implantation in a mouse model. To conduct this study, a conditional uterine knockout (KO) of Kiss1r was created using the Pgr-Cre (progesterone receptor-CRE recombinase) driver. Reproductive profiling revealed that while KO females exhibited normal ovarian function and mated successfully to stud males, they exhibited significantly fewer implantation sites, reduced litter size and increased neonatal mortality demonstrating that uterine KISS1R is required for embryo implantation and a healthy pregnancy. Strikingly, in the uterus of Kiss1r KO mice on day 4 (D4) of pregnancy, the day of embryo implantation, KO females exhibited aberrantly elevated epithelial ERα (estrogen receptor α) transcriptional activity. This led to the temporal misexpression of several epithelial genes [Cftr (Cystic fibrosis transmembrane conductance regulator), Aqp5 (aquaporin 5), Aqp8 (aquaporin 8) and Cldn7 (claudin 7)] that mediate luminal fluid secretion and luminal opening. As a result, on D4 of pregnancy, the lumen remained open disrupting the final acquisition of endometrial receptivity and likely accounting for the reduction in implantation events. Our data clearly show that uterine KISS1R negatively regulates ERα signaling at the time of implantation, in part by inhibiting ERα overexpression and preventing detrimentally high ERα activity. To date, there are no reports on the regulation of ERα by KISS1R; therefore, this study has uncovered an important and powerful regulator of uterine ERα during early pregnancy.

Compensatory feeding during early gestation for sows with a high weight loss after a summer lactation increased piglet birth weight but reduced litter size.

Sows mated in summer produce a greater proportion of born-light piglets (<1.1 kg) which contributes to increased carcass fatness in the progeny population. The reasons for the low birth weight of these piglets remain unclear, and there have been few successful mitigation strategies identified. We hypothesized that: 1) the low birth weight of progeny born to sows mated in summer may be associated with weight loss during the previous summer lactation; and 2) increasing early gestation feed allowance for the sows with high lactational weight loss in summer can help weight recovery and improve progeny birth weight. Sows were classified as having either low (av. 1%) or high (av. 7%) lactational weight loss in their summer lactation. All the sows with low lactational weight loss (LLStd) and half of the sows with high lactational weight loss received a standard gestation feeding regime (HLStd) (2.6 kg/d; day 0-30 gestation), whereas the rest of the sows with high lactational weight loss received a compensatory feed allowance (HLComp) (3.5 kg/d; day 0-30 gestation). A comparison of LLStd (n = 75) versus HLStd sows (n = 78) showed that this magnitude of weight loss over summer lactation did not affect the average piglet or litter birth weight, but such results may be influenced by the higher litter size (P = 0.030) observed in LLStd sows. A comparison of HLStd versus HLComp (n = 81) sows showed that the compensatory feeding increased (P = 0.021) weight gain of gestating sows by 6 kg, increased (P = 0.009) average piglet birth weight by 0.12 kg, tended to reduce (P = 0.054) the percentage of born-light piglets from 23.5% to 17.1% but reduced the litter size by 1.4 (P = 0.014). A subgroup of progeny stratified as born-light (0.8-1.1 kg) or -normal (1.3-1.7 kg) from each sow treatment were monitored for growth performance from weaning until 100 kg weight. The growth performance and carcass backfat of progeny were not affected by sow treatments. Born-light progeny had lower feed intake, lower growth rate, higher G:F, and higher carcass backfat than born-normal progeny (all P < 0.05). In summary, compensatory feeding from day 0 to 30 gestation in the sows with high weight loss during summer lactation reduced the percentage of born-light progeny at the cost of a lower litter size, which should improve growth rate and carcass leanness in the progeny population born to sows with high lactational weight loss.

Preliminary Study of Body Temperature Emissivity in Rabbits Selected for Litter Size Residual Variability

A divergent selection for litter size residual variability has been carried out in rabbits during 12 generations. Litter size residual variability was estimated as phenotypic variance of litter size within females after correcting for the year-season and the parity-lactation status effects. Stress causes an increase in core body temperature. Infrared thermography (IRT) has been shown to be a useful technique for identifying changes in body temperature emissivity. The aim of this work is to study the correlated response to selection for litter size residual variability in body temperature emissivity at natural mating. Natural mating can be considered a stressful stimulus for does. Temperature was measured in the eyeball by IRT before mating (basal temperature) and after 5 min, 30 min, and 60 min in does of the lines selected to decrease and to increase litter size residual variability (i.e., the Low and the High lines). Both lines showed similar basal temperature. Eyeball temperature was increased slightly in the Low line from basal state to 5 min after stressful stimulus (from 35.69 °C to 36.32 °C), and this increase remained up to 60 min after stress (36.55 °C). The High line showed a higher temperature than the Low line at 30 min (+0.96 °C, p = 0.99). At 60 min, temperature was similar between lines. The evolution of temperature was different between lines: the High line reached the peak of temperature later than the Low line (at 30 min vs. 5 min), and its peak was higher compared to the Low line (36.95 °C vs. 36.32 °C). In conclusion, the does selected for reducing litter size variability showed a lower increase in temperature after a stressful stimulus, therefore showing lower stress and consequently better welfare.

Comparison of the fertility of tumor suppressor gene-deficient C57BL/6 mouse strains reveals stable reproductive aging and novel pleiotropic gene

Tumor suppressor genes are involved in maintaining genome integrity during reproduction (e.g., meiosis). Thus, deleterious alleles in tumor suppressor-deficient mice would exhibit higher mortality during the perinatal period. A recent aging model proposes that perinatal mortality and age-related deleterious changes might define lifespan. This study aimed to quantitatively understand the relationship between reproduction and lifespan using three established tumor suppressor gene (p53, APC, and RECQL4)-deficient mouse strains with the same C57BL/6 background. Transgenic mice delivered slightly reduced numbers of 1st pups than wild-type mice [ratio: 0.81–0.93 (p = 0.1–0.61)] during a similar delivery period, which suggest that the tumor suppressor gene-deficient mice undergo relatively stable reproduction. However, the transgenic 1st pups died within a few days after birth, resulting in a further reduction in litter size at 3 weeks after delivery compared with that of wild-type mice [ratio: 0.35–0.68 (p = 0.034–0.24)] without sex differences, although the lifespan was variable. Unexpectedly, the significance of reproductive reduction in transgenic mice was decreased at the 2nd or later delivery. Because mice are easily affected by environmental factors, our data underscore the importance of defining reproductive ability through experiments on aging-related reproduction that can reveal a trade-off between fecundity and aging and identify RECQL4 as a novel pleiotropic gene.

99-OR: Effects of Early Time-Restricted Feeding during Gestation on Offspring Glucose Homeostasis in Mice

Time-Restricted Feeding (TRF) is an increasingly common diet that may improve insulin sensitivity. This practice merits study in the setting of pregnancy, as the diet is common, pregnancy represents a critical period for the health of both mother and offspring, and the effects of TRF during pregnancy on maternal gestational health and long-term offspring consequences remain unexamined. To test these effects, female mice were randomized to 6 hours of food availability in the dark cycle (early-time restricted feeding, eTRF), or given 24-hour ad libitum (AL) food access. After one week of acclimatization, females were mated. Food intake and body composition were measured weekly throughout gestation; insulin sensitivity was assessed at day 16 of pregnancy. Offspring birth rate, survival, birthweight, and gestational age were assessed. Body composition and food intake were assessed weekly. After 70 days on a normal diet, all offspring were switched to a 45% high-fat diet (HFD) with continued weekly monitoring. Glucose tolerance and insulin tolerance tests were conducted before and after 10 weeks of HFD feeding. Our data suggests that maternal eTRF does not affect birth weight or gestational age, but does reduce litter size (7.7 pups vs. 6.0 pups) and 3-day pup survival (95% vs. 58%) compared to AL. eTRF offspring had similar insulin and glucose tolerance compared to AL counterparts until adulthood (70 days of age). After 12 weeks of high-fat diet feeding, eTRF males develop concomitant glucose intolerance (auc, p&amp;lt;0.0001) and insulin sensitivity (auc, p=0.006), which was absent in females. These metabolic changes were present despite eTRF males having similar fat mass, body weight, and food intake when compared to AL males. Taken together, these data suggest that eTRF during pregnancy followed by offspring HFD feeding results in male-specific impaired glucose metabolism. Further work planned will evaluate the role of pancreatic islet insulin secretion in vivo and in vitro in future cohorts. Disclosure M. E. Carter: None. N. El habbal: None. D. S. Snyder: None. J. R. Redd: None. B. Gregg: None. D. Bridges: None. Funding National Institute of Diabetes and Digestive and Kidney Diseases (R01DK107535); University of Michigan

Goat AKAP12: Indel Mutation Detection, Association Analysis With Litter Size and Alternative Splicing Variant Expression.

A-kinase anchoring protein 12 (AKAP12) plays key roles in male germ cells and female ovarian granulosa cells, whereas its influence on livestock litter size remains unclear. Herein we detected the genetic variants of AKAP12 gene and their effects on litter size as well as alternative splicing variants expression in Shaanbei white cashmere (SBWC) goats, aiming at exploring theoretical basis for goat molecular breeding. We identified two Insertion/deletions (Indels) (7- and 13-bp) within the AKAP12 gene. Statistical analyses demonstrated that the 13-bp indel mutation in the 3′ UTR was significantly associated with litter size (n = 1,019), and the carriers with DD genotypes presented lower litter sizes compared with other carriers (P < 0.01). Bioinformatics analysis predicted that this 13-bp deletion sequence could bind to the seed region of miR-181, which has been documented to suppress porcine reproductive and respiratory syndrome virus (PRRSV) infection by targeting PRRSV receptor CD163 and affect the pig litter size. Therefore, luciferase assay for this 13-bp indel binding with miRNA-181 was performed, and the luciferase activity of pcDNA-miR-181-13bp-Deletion-allele vector was significantly lower than that of the pcDNA-miR-181-13bp-Insertion-allele vector (P < 0.05), suggesting the reduced binding capability with miR-181 in DD genotype. Given that alternative spliced variants and their expression considerably account for the Indel genetic effects on phenotypic traits, we therefore detected the expression of the alternative spliced variants in different tissues and identified that AKAP12-AS2 exhibited the highest expression levels in testis tissues. Interestingly, the AKAP12-AS2 expression levels of homozygote DD carriers were significantly lower than that of individuals with heterozygote ID, in both testis and ovarian tissues (P < 0.05), which is consistent with the effect of the 13-bp deletion on the reduced litter size. Taken together, our results here suggest that this 13-bp indel mutation within goat AKAP12 might be utilized as a novel molecular marker for improving litter size in goat breeding.

Maternal overweight induced by reduced litter size impairs the behavioral neurodevelopment of offspring

AimsWe assessed the influence of maternal overweight on the behavioral neurodevelopment of male and female offspring in prepubertal age by reducing the litter size. Main methodsTo reduce litter size in Wistar rats, the offspring of generation 0 (G0) were culled for 12 pups (6 males and 6 females: normal litter, NL-G1) or 4 pups (2 males and 2 females: small litter, SL-G1). In G1 dams, overweight was characterized, maternal behavior and locomotor activity were assessed. At G2, we quantified the ultrasonic vocalizations in post-natal day 5 (PND5); we evaluated olfactory discrimination in the homing behavior test on PND13; and in PND28–32 (prepubertal age), we performed the following tests: social play behavior, hole board, object recognition, and open field. At the end of the experiments, hippocampus and prefrontal cortex were dissected to quantify the synaptophysin by western blotting. Key findingsOur data demonstrated that a reduction in litter size was able to induce maternal overweight without altering the parameters related to overweight in the offspring. The SL-G2 offspring showed deficits in early social communication, olfactory discrimination, social play behavior, and the exploration of objects, in addition to increasing repetitive and stereotyped movements. There were also changes in the synaptophysin levels in the hippocampus and prefrontal cortex of the offspring from reduced litter dams. In conclusion, maternal overweight caused by litter reduction impairs behavioral neurodevelopment, inducing autism-like symptoms in the offspring. SignificanceThis study alerts the public about the negative consequences of maternal overweight in the descendants.

79 Direct and Indirect Effects of Heat Stress on the Hepatic and Ovarian Proteome in Gilts

Abstract Seasonal infertility (SI) caused by heat stress (HS) impacts the US swine industry by reducing litter size, farrowing rates, and production efficiency. Identifying the biological underpinnings of SI is a foundational step towards developing mitigation strategies to reduce the nearly $1 billion annual revenue losses to the swine industry. The study objective was to investigate the direct and indirect effects of HS via HS conditioned serum infusion in swine. We hypothesized gilts housed in thermoneutral (TN) conditions receiving gradual infusions of serum obtained from HS gilts would experience altered endocrine and metabolic function compared to gilts receiving serum from TN gilts. Prepubertal gilts (n = 18) were assigned to donor or recipient groups and donors were allocated to TN or HS environments. Blood was collected from HS donors and TN donors exposed to 24-hours of HS or TN conditions, respectively. Serum was infused into recipients housed in TN conditions via indwelling jugular catheters. Over a 24-hour period approximately 20% of the estimated recipient gilt serum volume from donors (pooled by treatment) was infused into recipients. After infusions were completed, gilts were euthanized and tissues collected. Increased rectal temperatures were observed in HS recipients compared to TN recipients (P ≤ 0.05). Protein extracts from liver and ovary underwent proteomic analysis via liquid-chromatography with tandem mass-spectrometry (LC-MS/MS) to assess protein abundance. In the liver and ovary, we identified 135 and 264 proteins, respectively, that were differentially abundant between TN and HS recipients (P &amp;lt; 0.10). Gene Ontology enrichment analysis identified alterations to pathways involved in hormone regulation, immune response, and apoptosis. Collectively, these data demonstrate gilts receiving HS serum experienced altered endocrine and metabolic function compared to gilts receiving TN serum. This project was supported in part by the Iowa Pork Producers Association. USDA is an equal opportunity provider and employer.

PSIII-1 Effect of Rearing Cross-fostered Piglets in Litters of Differing Size Relative to Sow Functional Teat Number on Pre-weaning Growth and Mortality

Abstract Litter sizes of commercial sows have increased recently, often resulting in the number of piglets exceeding the sow functional teat number. The objective of this study was to determine the effects of litter size after cross-fostering on piglet pre-weaning mortality (PWM) and growth. A RCBD was used with 13 blocks of 3 litters (total 39 litters/561 piglets); blocking factors were farrowing day, sow parity, body condition score, and functional teat number. Three Litter Size treatments (LS) relative to sow functional teat number were compared: Under (2 piglets below); Equal (same number of piglets); Over (2 piglets above). Piglets were weighed 24 h after birth and allotted to LS to create litters with similar gender ratio and average and CV of birth weight. Weaning was at 19.5 ± 0.50 d, weights and PWM were recorded. Piglet weight data were analyzed using PROC MIXED of SAS; PWM data were analyzed using PROC GLIMMIX of SAS. Models included LS and sow within block. Litter sizes averaged 12.1, 14.1, and 16.1 for the Under, Equal, and Over treatments, respectively (P ≤ 0.05). The Under treatment tended (P = 0.07) to have greater weaning weights compared to the Equal and Over treatments (Table 1). The Under treatment had lower (P ≤ 0.05) PWM than the Over treatment, with the Equal treatment being intermediate and not different to the other 2 (P &amp;gt; 0.05; Table 1). In conclusion, reducing litter size after cross-fostering to two piglets below the number of functional teats of the sow decreased PWM and tended to increase weaning weights.

Effects of Dexamethasone on Offspring Survival and Intrauterine Growth Restriction

The placenta is the primary organ responsible for deactivating maternal glucocorticoids and reducing fetal exposure. Glucocorticoid use during pregnancy is a common treatment for asthma, allergies, and COVID-19. Several studies have reported adverse effects including intrauterine growth restriction as a result of glucocorticoid exposure, yet little is known about the mechanisms by which short and long-term maternal glucocorticoid exposures affect placental biology and fetal development. To better understand the role of glucocorticoids on placental and fetal outcomes, we used a mouse model exposed to the synthetic glucocorticoid, dexamethasone (Dex), prior to and throughout gestation. We conducted a randomized controlled trial in mice with a treatment arm of Dex exposure and water exposure as control. Virgin C57Bl/6J female mice were single-housed at 11 weeks of age, and Dex was introduced in the drinking water as a 1mg/kg/day dose. After one week of treatment, mice were bred with age-matched virgin males. Dam body composition, food, and water intake were monitored weekly. Maternal insulin sensitivity, pup survival rate, litter size, and pup birth weight at postnatal day (PND) 0.5 were also assessed. Dams treated with Dex lost significant lean mass after one week of treatment. Dex treatment did not appear to affect the dams’ ability to get pregnant, as both groups carried pups to term with similar lengths of gestation (p=0.838). Water and Dex-treated dams gained comparable weight during the first and second trimesters of pregnancy, however, the Dex group gained less lean mass than the water group during the third trimester. At PND0.5, Dex dams had fewer pups with a 40% reduction in litter size (p=0.01) and lighter pups with a 37% reduction in offspring weight (p<0.001), indicating substantial intrauterine growth restriction. All pups of Dex-treated dams died by PND1. Attempts to rescue pups of Dex-dams by cross-fostering with water-treated nursing dams or by feeding the pups 10% glucose at PND0.5 failed by PND1. These results demonstrate a novel finding regarding the chronic use of glucocorticoids before and during conception and pregnancy. The reduction in both pup weight and late-pregnancy maternal weight gain suggests potential growth restriction or placental insufficiency. Further molecular studies during multiple time points of gestation will help elucidate the mechanisms at play.

Effects of Peripartal Sertraline on Maternal Calcium Metabolism and Maternal Bone Health

Abstract Lactation taxes mothers’ bone health, causing them to lose up to 10% of their bone mass for milk calcium. Selective serotonin reuptake inhibitor antidepressants (SSRIs) are commonly used during pregnancy and lactation but independently decrease bone mass. We previously demonstrated that both maternal and offspring bone densities were compromised by maternal treatment with the SSRI fluoxetine throughout pregnancy and lactation. In this study, we examined whether sertraline similarly affect maternal and offspring bone. Female C57BL/6 dams (n=23/group) were treated with sertraline (10 mg/kg/d) or a vehicle (DMSO) for 41 d (E0-lactation(L) 21). Pups were euthanized at weaning (L21). Dams were euthanized at peak lactation (L10, n=4/group), weaning (L21, n=9/group) or 3 mo post-weaning (n=10/group) for analysis. Sertraline treatment did not affect dams’ weight gain during pregnancy or lactation and did not impact milk production/consumption, measured by weigh-suckle-weigh. Unlike fluoxetine, which increases circulating calcium, sertraline treatment reduced serum calcium concentration at L21 compared with control (p&amp;lt;0.05). Mammary calcium genes were not altered at L10, but at L21 we observed decreased mammary expression of the calcium transporters Orai1, Spca1, Spca2, and Serca2 (p&amp;lt;0.05), and a tendency for decreased Pthlh (a calcium-regulating peptide; p=0.08). In the intestinal duodenum, Calb1 (a cytosolic calcium trafficking protein) expression was increased at L10 and L21 (p&amp;lt;0.05), and the calcium transporters Trpv6, Pmca1 and Spca2 were increased by L21 (p&amp;lt;0.05). Sertraline treatment did not affect L21 calcium concentration in either tissue, although the mammary gland calcium was 3.5 times that of the duodenum. Previously, we reported that circulating markers of bone formation (P1NP) or bone resorption (CTX) were unchanged in sertraline-treated dams at L21. This is unlike fluoxetine, which decreased P1NP without altering CTX. Furthermore, compared with control, sertraline treatment did not alter expression of bone resorption or formation genes (e.g. Trap, Rank/RankL, Alp, Runx2) in maternal femoral bone at L21 or 3 mo post-weaning. Interestingly, in utero exposure to sertraline reduced litter size (5.4 vs 6.8 pups/dam, p&amp;lt;0.01) and increased pup mortality (20% vs 5% dead pups/litter, p&amp;lt;0.01) during the first 24 hours postpartum compared with controls, but did not affect length of gestation or live birth rate. Exposure to sertraline during lactation did not alter weight gain in the surviving offspring, nor did it alter circulating calcium in the pups at weaning, suggesting an adequate supply of calcium in the milk from the dam. These data suggest that, compared with high-dose fluoxetine, low-dose peripartal sertraline has a milder impact on maternal bone and may reduce mammary calcium but could induce a failure to thrive in the offspring.

Evaluation of left ventricular function following myocardial infarction in adult postnatally overfed mice

Perinatal environment, such as nutritional state, is of major importance for short- and long-term cardio-metabolic status. Postnatal overfeeding (PNOF) induced in rodents by litter size reduction at birth reproduces the effects of childhood overnutrition and was shown to affect the cardiovascular function and to predispose to cardiovascular pathologies. The aim of our work was to follow the evolution of cardiac function for 28 days after in vivo myocardial infarction in control or PNOF mice. C57BL/6 male mice were raised in litter adjusted to 9 or 3 pups for control and PNOF group respectively. After weaning, mice of both groups had free access to standard diet and water. At 4 months, they were subjected to permanent ligation of the left anterior descending artery (LAD) to induce myocardial infarction or to sham surgery. Echocardiographic measurements were acquired at baseline and 1, 7, 15 and 28 days after surgery for cardiac function evaluation. Twenty-eight days after surgery, the left ventricle (LV) and lungs were weighed and infarct size was assessed. At basal state, no difference of cardiac function was observed between the 4 groups. In both control and PNOF mice subjected to LAD ligation, the fractional area change (FAC) was significantly decreased 24 h after surgery and the systolic/diastolic LV area was significantly increased 7 d after surgery, and both remained stable until 28 d. However, no differences neither in LV contractile function nor in infarct size were noticed between control and PNOF mice, except for an increased LV mass in PNOF mice. While all groups of mice subjected to myocardial infarction developed heart failure, as demonstrated by decreased LV contractility and dilation, there were no differences between control and PNOF groups. Further measures will be done in order to assess circulating biomarkers as cardiac troponin I (cTnI), brain natriuretic peptide (BNP) and growth differentiation factor-15 (GDF-15).

Postnatal overfeeding induces a higher cardiac sensitivity to in vivo ischemia-reperfusion injury at all ages in male mice, but only in young females

Nutritional disturbances during the postnatal period may be responsible for a predisposition in adulthood to increased cardio-metabolic risk and a greater myocardial vulnerability to ischemia. However, these data have mainly been obtained in young male mice, but less is known for females and for older animals. Evaluate the impact of postnatal overfeeding on: – cardiac sensitivity after in vivo ischemia-reperfusion (I-R) on both sexes; – in young (4 months), adult (6 months) and mature (12 months) mice. PNOF was induced by reduction of litter size of C57/BL6 mice immediately after birth: normally-fed group (NF) litters were composed of 9 pups/mother and overfed group litters (OF) of 3 pups/mother. The in vivo ischemia was induced by a 45 min ligation of the left anterior interventricular artery, followed by 24 hours of reperfusion, in hearts from 4-, 6- and 12-months aged male and female mice. The area at risk (AAR) was determined by Evans blue coloration and the infarct size by TTC staining. PNOF induced an early and permanent increase in body weight in OF group, for males (4 months: +13%; 6 months: +23%; 12 months: +23%) and female mice (4 months: +23%; 6 months: +27%; 12 months: +15%). A significant increase of infarct size was observed in hearts of overfed male mice aged at all ages (4 months: +37%, 6 months: +32% and 12 months: +38% of AAR), but for females, infarct size was significant increased at 4 months (+34%), but not at 6 and 12 months. However, in all female groups (NF and OF) we observed a higher post-surgical mortality and a greater data variability as compared to males. Nutritional programming through short-term PNOF induced a higher susceptibility to myocardial I-R injury in vivo at all ages in male mice, but only in young females. The mechanism of this sexual dimorphism in our model is not well understood, but could involve distinct levels of cardioprotective pathways expression, related to hormonal status.

Reduction of litter size during lactation in rats greatly influences fatty acid profiles in dams.

This study aimed to determine in lactating rats how fatty acid profiles are affected by litter size. On day 2 after parturition, litters of lactating rats were adjusted to a normal litter size of 9 pups/dam (NL) or to a small litter of 4 pups/dam (SL), and dams were studied at day 21 of lactation. Plasma glucose, insulin, and docosahexaenoic acid (DHA) concentrations were higher in SL than in NL dams, whereas the concentrations of most other fatty acids, triacylglycerols (TAG), and non-esterified fatty acids were lower in the SL dams. In the liver, the concentration of TAG was lower in SL than in NL dams as was the concentration of most fatty acids, with the exception of stearic acid (STA), arachidonic acid (ARA), and DHA concentrations that were higher in SL. Both plasma and liver Δ9 desaturase indices were lower in SL than in NL dams, whereas both Δ5 and Δ6 desaturase indices were higher in SL dams. In the liver, the expression of acetyl CoA carboxylase was lower in SL than in NL dams, and among the different adipose tissue depots, only mesenteric adipose tissue showed a higher concentration of most fatty acids in SL than in NL dams. It is proposed that reduction of litter size during lactation decreases liver lipogenesis de novo, although the synthesis of long-chain polyunsaturated fatty acids from their corresponding precursors increases, and lipolytic activity in mesenteric adipose tissue decreases probably as result of increased insulin responsiveness.

Zearalenone and the Immune Response.

Zearalenone (ZEA) is an estrogenic fusariotoxin, being classified as a phytoestrogen, or as a mycoestrogen. ZEA and its metabolites are able to bind to estrogen receptors, 17β-estradiol specific receptors, leading to reproductive disorders which include low fertility, abnormal fetal development, reduced litter size and modification at the level of reproductive hormones especially in female pigs. ZEA has also significant effects on immune response with immunostimulatory or immunosuppressive results. This review presents the effects of ZEA and its derivatives on all levels of the immune response such as innate immunity with its principal component inflammatory response as well as the acquired immunity with two components, humoral and cellular immune response. The mechanisms involved by ZEA in triggering its effects are addressed. The review cited more than 150 publications and discuss the results obtained from in vitro and in vivo experiments exploring the immunotoxicity produced by ZEA on different type of immune cells (phagocytes related to innate immunity and lymphocytes related to acquired immunity) as well as on immune organs. The review indicates that despite the increasing number of studies analyzing the mechanisms used by ZEA to modulate the immune response the available data are unsubstantial and needs further works.

Effects of moderate intensity endurance training and high-intensity interval training on the reproductive parameters of wistar rats overfed in infancy.

Studies indicate that rapid weight gain at critical development stages, such as the lactation period, is associated with the development of obesity, cardiovascular diseases, and diabetes in the long term. In addition to metabolic changes during adulthood, overweight/obesity may influence reproductive function. Human and animal studies suggest that lifestyle changes through exercise and/or controlled diet result in improved semen quality in obese individuals. However, the relationship between exercise volume/intensity and reproductive capacity effects remains inconclusive. The present study aimed to evaluate the effects of moderate intensity endurance training and high-intensity interval training (HIIT) on the reproductive parameters of lactating overfed male Wistar rats. Postnatal overfeeding was induced by applying the litter size reduction method. Forty males Wistar rats were used, divided into four groups: one with control litters (CLs) (10 animals/litter-sedentary) and three with small litters (SLs) (4 animals/litter), divided into sedentary, moderate endurance training, and HIIT. Morphologic, metabolic, and reproductive variables were analyzed. SL sedentary group showed increased body weight, adiposity, and decreased relative weight of the seminal vesicle, prostate, and epididymis as well as changes in the insulin tolerance and oral glucose tolerance tests glycemic tests compared to CL sedentary group. Endurance and HIIT protocols were efficient in improving the glycemic metabolism, central fat accumulation of trained groups and did not affect reproductive parameters. Endurance and HIIT protocols proved to be effective in reversing these metabolic changes without impairing the evaluated reproductive parameters.

Neonatal overfeeding during lactation rapidly and permanently misaligns the hepatic circadian rhythm and programmes adult NAFLD

Childhood obesity is a strong risk factor for adult obesity, type 2 diabetes, and cardiovascular disease. The mechanisms that link early adiposity with late-onset chronic diseases are poorly characterised. We developed a mouse model of early adiposity through litter size reduction. Mice reared in small litters (SLs) developed obesity, insulin resistance, and hepatic steatosis during adulthood. The liver played a major role in the development of the disease. ObjectiveTo gain insight into the molecular mechanisms that link early development and childhood obesity with adult hepatic steatosis and insulin resistance. MethodsWe analysed the hepatic transcriptome (Affymetrix) of control and SL mice to uncover potential pathways involved in the long-term programming of disease in our model. ResultsThe circadian rhythm was the most significantly deregulated Gene Ontology term in the liver of adult SL mice. Several core clock genes, such as period 1–3 and cryptochrome 1–2, were altered in two-week-old SL mice and remained altered throughout their life course until they reached 4–6 months of age. Defective circadian rhythm was restricted to the periphery since the expression of clock genes in the hypothalamus, the central pacemaker, was normal. The period-cryptochrome genes were primarily entrained by dietary signals. Hence, restricting food availability during the light cycle only uncoupled the central rhythm from the peripheral and completely normalised hepatic triglyceride content in adult SL mice. This effect was accompanied by better re-alignment of the hepatic period genes, suggesting that they might have played a causal role in mediating hepatic steatosis in the adult SL mice. Functional downregulation of Per2 in hepatocytes in vitro confirmed that the period genes regulated lipid-related genes in part through peroxisome proliferator-activated receptor alpha (Ppara). ConclusionsThe hepatic circadian rhythm matures during early development, from birth to postnatal day 30. Hence, nutritional challenges during early life may misalign the hepatic circadian rhythm and secondarily lead to metabolic derangements. Specific time-restricted feeding interventions improve metabolic health in the context of childhood obesity by partially re-aligning the peripheral circadian rhythm.

Neonatal overfeeding reduces estradiol plasma levels and disrupts noradrenergic-kisspeptin-GnRH pathway and fertility in adult female rats

This work evaluated the effects of neonatal overfeeding, induced by litter size reduction, on fertility and the noradrenaline-kisspeptin-gonadotrophin releasing hormone (GnRH) pathway in adult female rats. The litter size was adjusted to 3 pups with each mother in the small litters (SL) and 10 pups with each mother in the normal litters (NL). SL females exhibited metabolic changes associated with reproductive dysfunctions, shown by earlier vaginal opening and first estrus, later regular cyclicity onset, and lower and higher occurrences of estrus and diestrus phases, respectively, as well as reduced fertility, estradiol plasma levels, and mRNA expressions of tyrosine hydroxylase in the locus coeruleus, kisspeptin, and GnRH in the preoptic area in adult females in the afternoon of proestrus. These results suggest that neonatal overfeeding in female rats promotes reproductive dysfunctions in adulthood, such as lower estradiol plasma levels associated with impairments in fertility and noradrenaline-kisspeptin-GnRH pathway during positive feedback.

Correlated Response to Selection for Litter Size Residual Variability in Rabbits' Body Condition.

Simple SummarySelection for decreasing litter size residual variance has been proposed as an indirect way to select for resilience. Resilience has been directly related to welfare. A good body condition and efficient body fat mobilization have been associated with an optimal level of animal welfare. Two rabbit lines have been divergently selected for litter size residual variability. The low line selected for decreasing litter size variance more efficiently managed the body fat from mating to weaning in the second productive cycle in females compared to the high line, which could be related to the lower culling rate reported previously in the low line. Therefore, body condition can be used as a useful biomarker of resilience.A divergent selection experiment for residual variance of litter size at birth was carried out in rabbits during twelve generations. Residual variance of litter size was estimated as the within-doe variance of litter size after pre-correction for year and season as well as parity and lactation status effects. The aim of this work was to study the correlated response to selection for litter size residual variability in body condition from mating to weaning. Body condition is related directly to an animal’s fat deposits. Perirenal fat is the main fat deposit in rabbits. Individual body weight (IBW) and perirenal fat thickness (PFT) were used to measure body condition at second mating, delivery, 10 days after delivery, and weaning. Litter size of the first three parities was analyzed. Both lines decreased body condition between mating to delivery; however, the decrease in body condition at delivery was lower in the low line, despite this line having higher litter size at birth (+0.54 kits, p = 0.93). The increment of body condition between delivery and early lactation was slightly higher in the low line. On the other hand, body condition affected success of females’ receptivity and fertility at the third mating, e.g., receptive females showed a higher IBW and PFT than unreceptive ones (+129 g and +0.28 mm, respectively), and fertile females had a higher IBW and PFT than unfertile ones (+82 g and +0.28 mm, respectively). In conclusion, the does selected for reducing litter size variability showed a better deal with situations of high-energy demand, such as delivery and lactation, than those selected for increasing litter size variability, which would agree with the better health and welfare condition in the low line.