A Calcium-Deficient Diet in Rat Dams during Gestation and Nursing Affects Hepatic 11β-hydroxysteroid dehydrogenase-1 Expression in the Offspring

Background

Prenatal malnutrition can affect the phenotype of offspring by changing epigenetic regulation of specific genes. Several lines of evidence demonstrate that calcium (Ca) plays an important role in the pathogenesis of insulin resistance syndrome. We hypothesized that pregnant female rats fed a Ca-deficient diet would have offspring with altered hepatic glucocorticoid-related gene expression and that lactation would modify these alterations.

Methodology

We determined the effects of Ca deficiency during pregnancy and/or lactation on hepatic 11β-hydroxysteroid dehydrogenase-1 (Hsd11b1) expression in offspring. Female Wistar rats consumed either a Ca-deficient (D: 0.008% Ca) or control (C: 0.90% Ca) diet ad libitum from 3 weeks preconception to 21 days postparturition. On postnatal day 1, pups were cross-fostered to the same or opposite dams and divided into the following four groups: CC, DD, CD, and DC (first letter: original mother''s diet; second letter: nursing mother''s diet). All offspring were fed a control diet beginning at weaning (day 21) and were killed on day 200±7. Serum insulin and adipokines in offspring were measured using ELISA kits.

Principal Findings

In males, mean levels of insulin, glucose, and Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) were higher in the DD and DC groups than in the CC group. We found no difference in HOMA-IR between the CC and CD groups in either males or females. Expression of Hsd11b1 was lower in male DD rats than in CC rats. Hsd11b1 expression in male offspring nursed by cross-fostered dams was higher than that in those nursed by dams fed the same diet; CC vs. CD and DD vs. DC. In females, Hsd11b1 expression in DC rats was higher than that in CC rats.

Conclusions

These findings indicated that maternal Ca restriction during pregnancy and/or lactation alters postnatal growth, Hsd11b1 expression, and insulin resistance in a sex-specific manner.     

Pre-Weaning Growth Hormone Treatment Reverses Hypertension and Endothelial Dysfunction in Adult Male Offspring of Mothers Undernourished during Pregnancy

Maternal undernutrition results in elevated blood pressure (BP) and endothelial dysfunction in adult offspring. However, few studies have investigated interventions during early life to ameliorate the programming of hypertension and vascular disorders. We have utilised a model of maternal undernutrition to examine the effects of pre-weaning growth hormone (GH) treatment on BP and vascular function in adulthood. Female Sprague-Dawley rats were fed either a standard control diet (CON) or 50% of CON intake throughout pregnancy (UN). From neonatal day 3 until weaning (day 21), CON and UN pups received either saline (CON-S, UN-S) or GH (2.5 ug/g/day)(CON-GH, UN-GH). All dams were fed ad libitum throughout lactation. Male offspring were fed a standard diet until the end of the study. Systolic blood pressure (SBP) was measured at day 150 by tail cuff plethysmography. At day 160, intact mesenteric vessels mounted on a pressure myograph. Responses to pressure, agonist-induced constriction and endothelium-dependent vasodilators were investigated to determine vascular function. SBP was increased in UN-S groups and normalised in UN-GH groups (CON-S 121±2 mmHg, CON-GH 115±3, UN-S 146±3, UN-GH 127±2). Pressure mediated dilation was reduced in UN-S offspring and normalised in UN-GH groups. Vessels from UN-S offspring demonstrated a reduced constrictor response to phenylephrine and reduced vasodilator response to acetylcholine (ACh). Furthermore, UN-S offspring vessels displayed a reduced vasodilator response in the presence of L-NG-Nitroarginine Methyl Ester (L-NAME), carbenoxolone (CBX), L-NAME and CBX, Tram-34 and Apamin. UN-GH vessels showed little difference in responses when compared to CON and significantly increased vasodilator responses when compared to UN-S offspring. Pre-weaning GH treatment reverses the negative effects of maternal UN on SBP and vasomotor function in adult offspring. These data suggest that developmental cardiovascular programming is potentially reversible by early life GH treatment and that GH can reverse the vascular adaptations resulting from maternal undernutrition.     

Perinatal salt restriction: a new pathway to programming adiposity indices in adult female Wistar rats

Low birth weight has been associated with increased obesity in adulthood. It has been shown that dietary salt restriction during intrauterine life induces low birth weight and insulin resistance in adult Wistar rats. The present study had a two-fold objective: to evaluate the effects that low salt intake during pregnancy and lactation has on the amount and distribution of adipose tissue; and to determine whether the phenotypic changes in fat mass in this model are associated with alterations in the activity of the renin-angiotensin system. Maternal salt restriction was found to reduce birth weight in male and female offspring. In adulthood, the female offspring of dams fed the low-salt diet presented higher adiposity indices than those seen in the offspring of dams fed a normal-salt diet. This was attributed to the fact that adipose tissue mass (retroperitoneal but not gonadal, mesenteric or inguinal) was greater in those rats than in the offspring of dams fed a normal diet. The adult offspring of dams fed the low-salt diet, compared to those dams fed a normal-salt diet, presented the following: plasma leptin levels higher in males and lower in females; plasma renin activity higher in males but not in females; and no differences in body weight, mean arterial blood pressure or serum angiotensin-converting enzyme activity. Therefore, low salt intake during pregnancy might lead to the programming of obesity in adult female offspring.     

Maternal cigarette smoke exposure contributes to glucose intolerance and decreased brain insulin action in mice offspring independent of maternal diet

Background

Maternal smoking leads to intrauterine undernutrition and is associated with low birthweight and higher risk of offspring obesity. Intrauterine smoke exposure (SE) may alter neuroendocrine mediators regulating energy homeostasis as chemicals in cigarette smoke can reach the fetus. Maternal high-fat diet (HFD) consumption causes fetal overnutrition; however, combined effects of HFD and SE are unknown. Thus we investigated the impact of combined maternal HFD and SE on adiposity and energy metabolism in offspring.

Method

Female Balb/c mice had SE (2 cigarettes/day, 5 days/week) or were sham exposed for 5 weeks before mating. Half of each group was fed HFD (33% fat) versus chow as control. The same treatment continued throughout gestation and lactation. Female offspring were fed chow after weaning and sacrificed at 12 weeks.

Results

Birthweights were similar across maternal groups. Faster growth was evident in pups from SE and/or HFD dams before weaning. At 12 weeks, offspring from HFD-fed dams were significantly heavier than those from chow-fed dams (chow-sham 17.6±0.3 g; chow-SE 17.8±0.2 g; HFD-sham 18.7±0.3 g; HFD-SE 18.8±0.4 g, P<0.05 maternal diet effect); fat mass was significantly greater in offspring from chow+SE, HFD+SE and HFD+sham dams. Both maternal HFD and SE affected brain lactate transport. Glucose intolerance and impaired brain response to insulin were observed in SE offspring, and this was aggravated by maternal HFD consumption.

Conclusion

While maternal HFD led to increased body weight in offspring, maternal SE independently programmed adverse health outcomes in offspring. A smoke free environment and healthy diet during pregnancy is desirable to optimize offspring health.     

Development of Cheaper Embryo Vitrification Device Using the Minimum Volume Method

This study was designed to compare the efficiency of the Cryotop and Calibrated plastic inoculation loop (CPIL) devices for vitrification of rabbit embryos on in vitro development and implantation rate, offspring rate at birth and embryonic and fetal losses. CPIL is a simple tool used mainly by microbiologists to retrieve an inoculum from a culture of microorganisms. In experiment 1, embryos were vitrified using a Cryotop device and a CPIL device. There were no significant differences in hatched/hatching blastocyst stage rates after 48 h of culture among the vitrified groups (62±4.7% and 62±4.9%, respectively); however, the rates were significantly lower (P<0.05) than those of the fresh group (95±3.4%). In experiment 2, vitrified embryos were transferred using laparoscopic technique. The number of implanted embryos was estimated by laparoscopy as number of implantation sites at day 14 of gestation. At birth, total offspring were recorded. Embryonic and fetal losses were calculated as the difference between implanted embryos and embryos transferred and total born at birth and implanted embryos, respectively. The rate of implantation and development to term was similar between both vitrification devices (56±7.2% and 50±6.8% for implantation rate and 40±7.1% and 35±6.5% for offspring rate at birth); but significantly lower than in the fresh group (78±6.6% for implantation rate and 70±7.2% for offspring rate at birth, P<0.05). Likewise, embryonic losses were similar between both vitrification devices (44±7.2% and 50±6.8%), but significantly higher than in the fresh group (23±6.6%, P < 0.05). However, fetal losses were similar between groups (10±4.4%, 15±4.8% and 8±4.2%, for vitrified, Cryotop or CPIL and fresh, respectively). These results indicate that the CPIL device is as effective as the Cryotop device for vitrification of rabbit embryos, but at a cost of €0.05 per device.     

Malnutrition in utero and lactation: relation between the weight gained by the mothers and the development of their offspring

Physiological weight changes in rat dams and their offspring as sequelae of malnutrition during pregnancy and lactation have been studied. Daily monitoring of the body weight as well as the consumption of food (malnutrition dams 14 g during pregnancy and 20 g during lactation) and drink in control and malnutrition dams was conducted. The number of pregnant dams that completed their pregnant period successfully was registered as well as the number and weight of the pups at birth and their evolution over a period of a month. The percentage of mortality of the pups during that period has been studied. The present results indicate a highly significant decrease in body weight in experimental dams, which determines a retardation in the physiological development of the pups, and yields a higher percentage of mortality in the experimental animals than in controls. It can thus be concluded that malnutrition in utero and during lactation affects the ratio between weight gain for dams and the physical development of their pups.     

Gestational Heat Stress Alters Postnatal Offspring Body Composition Indices and Metabolic Parameters in Pigs

The study objectives were to test the hypothesis that heat stress (HS) during gestational development alters postnatal growth, body composition, and biological response to HS conditions in pigs. To investigate this, 14 first parity crossbred gilts were exposed to one of four environmental treatments (TNTN, TNHS, HSTN, or HSHS) during gestation. TNTN and HSHS dams were exposed to thermal neutral (TN, cyclical 18–22°C) or HS conditions (cyclical 28–34°C) during the entire gestation, respectively. Dams assigned to HSTN and TNHS treatments were heat-stressed for the first or second half of gestation, respectively. Postnatal offspring were exposed to one of two thermal environments for an acute (24 h) or chronic (five weeks) duration in either constant TN (21°C) or HS (35°C) environment. Exposure to chronic HS during their growth phase resulted in decreased longissimus dorsi cross-sectional area (LDA) in offspring from HSHS and HSTN treated dams whereas LDA was larger in offspring from dams in TNTN and TNHS conditions. Irrespective of HS during prepubertal postnatal growth, pigs from dams that experienced HS during the first half of gestation (HSHS and HSTN) had increased (13.9%) subcutaneous fat thickness compared to pigs from dams exposed to TN conditions during the first half of gestation. This metabolic repartitioning towards increased fat deposition in pigs from dams heat-stressed during the first half of gestation was accompanied by elevated blood insulin concentrations (33%; P = 0.01). Together, these results demonstrate HS during the first half of gestation altered metabolic and body composition parameters during future development and in biological responses to a subsequent HS challenge.     

Early renal structure alteration in rat offspring from dams fed low protein diet

To investigate the early renal alterations due to severe maternal protein restriction (MPR) Wistar dams received 23% (normal protein, NP) or 5% (low protein, LP) chow during gestation and lactation periods. In NP offspring at birth, the cortex-to-medulla (C/M) ratio was 35% greater in female than in male offspring and the mature/immature glomeruli ratio was lower in both sexes of LP offspring than in the matched NP ones (by 20%). At birth and at weaning the kidney of the LP offspring showed fewer glomeruli (40% less) than the age-matched NP offspring. The NP female offspring had almost 20% fewer glomeruli than the matched male offspring. At weaning, the number of glomeruli was positively correlated with BM at birth (R=0.86; P<0.001). The effects of gender and maternal protein restriction, both individually and overall, based on biometrical and stereological parameters were: day 1, MPR largely responsible for the majority of alterations observed in LP groups, however gender influenced C/M ratio; day 21, MPR and gender interacted and modified the number of glomeruli per kidney. The early adverse of MPR effect on renal development is disproportionate between mature and immature glomeruli at birth leading to fewer glomeruli at weaning. This supports epidemiological data in humans underlying why fetuses with low birth weight carry an increased risk of mortality from chronic diseases in adulthood, including hypertension.     

High-protein diet during gestation and lactation affects mammary gland mRNA abundance, milk composition and pre-weaning litter growth in mice

We evaluated the effect of a high-protein diet (HP) on pregnancy, lactational and rearing success in mice. At the time of mating, females were randomly assigned to isoenergetic diets with HP (40% w/w) or control protein levels (C; 20%). After parturition, half of the dams were fed the other diet throughout lactation resulting in four dietary groups: CC (C diet during gestation and lactation), CHP (C diet during gestation and HP diet during lactation), HPC (HP diet during gestation and C diet during lactation) and HPHP (HP diet during gestation and lactation). Maternal and offspring body mass was monitored. Measurements of maternal mammary gland (MG), kidney and abdominal fat pad masses, MG histology and MG mRNA abundance, as well as milk composition were taken at selected time points. HP diet decreased abdominal fat and increased kidney mass of lactating dams. Litter mass at birth was lower in HP than in C dams (14.8 v. 16.8 g). Dams fed an HP diet during lactation showed 5% less food intake (10.4 v. 10.9 g/day) and lower body and MG mass. On day 14 of lactation, the proportion of MG parenchyma was lower in dams fed an HP diet during gestation as compared to dams fed a C diet (64.8% v. 75.8%). Abundance of MG α-lactalbumin, β-casein, whey acidic protein, xanthine oxidoreductase mRNA at mid-lactation was decreased in all groups receiving an HP diet either during gestation and/or lactation. Milk lactose content was lower in dams fed an HP diet during lactation compared to dams fed a C diet (1.6% v. 2.0%). On days 14, 18 and 21 of lactation total litter mass was lower in litters of dams fed an HP diet during lactation, and the pups' relative kidney mass was greater than in litters suckled by dams receiving a C diet. These findings indicate that excess protein intake in reproducing mice has adverse effects on offspring early in their postnatal growth as a consequence of impaired lactational function.     

Growth and survival of New Zealand sea lions, <Emphasis Type="Italic">Phocarctos hookeri:</Emphasis> birth to 3 months

Offspring birth mass and growth rate represent important life history traits, which influence many vital population and individual characteristics, while offspring survival is a key factor in variation in female reproductive success. For a threatened population of pinnipeds, such as New Zealand sea lions, Phocarctos hookeri, (Grey, 1844, NZ sea lions), understanding individual life history parameters and population dynamics is vital for their management and conservation. This is the first study of the behaviour of females during parturition, pup birth mass and growth, and pre-weaning survival of NZ sea lions, Enderby Island, Auckland Islands during austral summer breeding seasons, 2001/2002 to 2003/2004. Pregnant females arrived ashore 2.1 ± 0.16 days prior to giving birth. After parturition, mothers suckled their pups for 8.6 ± 0.16 days before leaving on their first foraging trip. Male pups were born significantly heavier than female (males 10.6 ± 1.4 kg, females 9.7 ± 0.9 kg). Pups lost on average 48 ± 0.14 g per day mass during the early postpartum period (between birth and mothers first foraging trip). Pup mortality did not vary by pup sex, birth mass, date of birth or any maternal characteristics however it varied significantly between years due to a bacterial infection epidemic (Pup mortality at 60 days: 2001 32%; 2002 21%; 2003 12%). The absolute growth rate per day for pups was 151 g/day over all years. Pup growth rate measured as the slope of linear line fitted to pup mass by age was consistently higher for pups with heavier birth mass, male pups and during the 2002 season. High offspring mortality and slow growth rates coupled with maternal foraging behaviour at their physiological limits may reflect a threatened species which has limited ability for population growth in an environment which is at the extreme of their historical range and impacted upon by fisheries.     

Excess Maternal Salt Intake Produces Sex-Specific Hypertension in Offspring: Putative Roles for Kidney and Gastrointestinal Sodium Handling

Hypertension is common and contributes, via cardiovascular disease, towards a large proportion of adult deaths in the Western World. High salt intake leads to high blood pressure, even when occurring prior to birth – a mechanism purported to reside in altered kidney development and later function. Using a combination of in vitro and in vivo approaches we tested whether increased maternal salt intake influences fetal kidney development to render the adult individual more susceptible to salt retention and hypertension. We found that salt-loaded pregnant rat dams were hypernatraemic at day 20 gestation (147±5 vs. 128±5 mmoles/L). Increased extracellular salt impeded murine kidney development in vitro, but had little effect in vivo. Kidneys of the adult offspring had few structural or functional abnormalities, but male and female offspring were hypernatraemic (166±4 vs. 149±2 mmoles/L), with a marked increase in plasma corticosterone (e.g. male offspring; 11.9 [9.3–14.8] vs. 2.8 [2.0–8.3] nmol/L median [IQR]). Furthermore, adult male, but not female, offspring had higher mean arterial blood pressure (effect size, +16 [9–21] mm Hg; mean [95% C.I.]. With no clear indication that the kidneys of salt-exposed offspring retained more sodium per se, we conducted a preliminary investigation of their gastrointestinal electrolyte handling and found increased expression of proximal colon solute carrier family 9 (sodium/hydrogen exchanger), member 3 (SLC9A3) together with altered faecal characteristics and electrolyte handling, relative to control offspring. On the basis of these data we suggest that excess salt exposure, via maternal diet, at a vulnerable period of brain and gut development in the rat neonate lays the foundation for sustained increases in blood pressure later in life. Hence, our evidence further supports the argument that excess dietary salt should be avoided per se, particularly in the range of foods consumed by physiologically immature young.     

The Weaker Sex? The Propensity for Male-Biased Piglet Mortality

For the most part solutions to farm animal welfare issues, such as piglet mortality, are likely to lie within the scientific disciplines of environmental design and genetic selection, however understanding the ecological basis of some of the complex dynamics observed between parent and offspring could make a valuable contribution. One interesting, and often discussed, aspect of mortality is the propensity for it to be sex-biased. This study investigated whether known physiological and behavioural indicators of piglet survival differed between the sexes and whether life history strategies (often reported in wild or feral populations) relating to parental investment were being displayed in a domestic population of pigs. Sex ratio (proportion of males (males/males+females)) at birth was 0.54 and sex allocation (maternal investment measured as piglet birth weight/litter weight) was statistically significantly male-biased at 0.55 (t₃₅ = 2.51 P = 0.017), suggesting that sows invested more in sons than daughters during gestation. Despite this investment in birth weight, a known survival indicator, total pre-weaning male mortality was statistically significantly higher than female mortality (12% vs. 7% respectively z = 2.06 P = 0.040). Males tended to suffer from crushing by the sow more than females and statistically significantly more males died from disease-related causes. Although males were born on average heavier, with higher body mass index and ponderal index, these differences were not sustained. In addition male piglets showed impaired thermoregulation compared to females. These results suggest male-biased mortality exists despite greater initial maternal investment, and therefore reflects the greater susceptibility of this sex to causal mortality factors. Life history strategies are being displayed by a domestic population of pigs with sows in this study displaying a form of parental optimism by allocating greater resources at birth to males and providing an over-supply of this more vulnerable sex in expectation of sex-biased mortality.     

Chromosomal Polymorphism and Female Receptivity in a Natural Population of DROSOPHILA PERSIMILIS

In a natural population of Drosophila persimilis (McDonald Ranch, Napa Valley, California), KL and MD chromosomal arrangement frequencies undergo a seasonal cycle, with MD common in spring and KL common in summer. Samples collected from spring and summer provided isofemale strains established as homozygous KL and MD pairs (kinlines) with each pair derived from a single heterokaryotype wild progenitor. Haploid doses of chromosomes 2 and 4 were controlled by marker-cross derivations of kinlines. Percentage onset of female receptivity was measured from cultures at 25° and at 15°, using ten kinlines from spring and nine from summer collections, with fast-mating hybrid males as standard testers. Mating tests consisted of 20 tester males x 20 females of specific age, karyotype, and kinline observed for 30 min. At 25° females became receptive at 48 hr after eclosion: parental line (KL_i/KL_i and MD_i/MD_i) females were approximately equal at 55 to 60% receptive, while among hybrids, MD_i/MD_j homokaryotype females were significantly less receptive (68%) than all other outbred combinations (73 to 77%). At 15°, females became receptive at four days of age, with increases on the fifth and sixth days: both parental line and outbred MD/MD females were significantly more receptive (28% at four days and 62% at six days) than all heterokaryotype females (20 to 26% at four days and 55 to 59% at six days), which in turn were more receptive than KL/KL parental and outbred females (10% at four days and 40% at six days). Heterosis was expressed at 25°, but not at 15°. Thus, dominance for female receptivity was temperature dependent. Females polymorphic for these third chromosomal karyotypes possess differential temperature sensitivity for onset of receptivity and are likely to contribute in a significant way to the observed seasonal frequency cycle in the natural population from which they have been derived.     

Chronic Maternal Vitamin B12 Restriction Induced Changes in Body Composition & Glucose Metabolism in the Wistar Rat Offspring Are Partly Correctable by Rehabilitation

Maternal under-nutrition increases the risk of developing metabolic diseases. We studied the effects of chronic maternal dietary vitamin B12 restriction on lean body mass (LBM), fat free mass (FFM), muscle function, glucose tolerance and metabolism in Wistar rat offspring. Prevention/reversibility of changes by rehabilitating restricted mothers from conception or parturition and their offspring from weaning was assessed. Female weaning Wistar rats (n = 30) were fed ad libitum for 12 weeks, a control diet (n = 6) or the same with 40% restriction of vitamin B12 (B12R) (n = 24); after confirming deficiency, were mated with control males. Six each of pregnant B12R dams were rehabilitated from conception and parturition and their offspring weaned to control diet. While offspring of six B12R dams were weaned to control diet, those of the remaining six B12R dams continued on B12R diet. Biochemical parameters and body composition were determined in dams before mating and in male offspring at 3, 6, 9 and 12 months of their age. Dietary vitamin B12 restriction increased body weight but decreased LBM% and FFM% but not the percent of tissue associated fat (TAF%) in dams. Maternal B12R decreased LBM% and FFM% in the male offspring, but their TAF%, basal and insulin stimulated glucose uptake by diaphragm were unaltered. At 12 months age, B12R offspring had higher (than controls) fasting plasma glucose, insulin, HOMA-IR and impaired glucose tolerance. Their hepatic gluconeogenic enzyme activities were increased. B12R offspring had increased oxidative stress and decreased antioxidant status. Changes in body composition, glucose metabolism and stress were reversed by rehabilitating B12R dams from conception, whereas rehabilitation from parturition and weaning corrected them partially, highlighting the importance of vitamin B12 during pregnancy and lactation on growth, muscle development, glucose tolerance and metabolism in the offspring.     

Effects of folic acid and amino acids supplementation on zinc intestinal absorption in the progeny of ethanol-treated rats

This study was designed to examine the effects of supplementation with folic acid and amino acids in dams that consumed ethanol during gestation and lactation to see whether there is an improvement in the intestinal absorption of zinc in pup rats on the 21st day after birth. The rats were randomized into two groups: Ethanol-rats (EG) were administered ethanol during the pregnancy and lactation periods; the ethanol-folic acid group (EFG) received a folic acid and amino acid supplement concomitantly with ethanol administration during pregnancy and lactation. The dams were mated to obtain the first offspring. Two sets of experiments were performed on the offspring at 21 days after birth. In general, in the first set, jejunal zinc absorption in the offspring of EG and EFG groups showed a gradual increase along with increased perfusion time at all assayed concentrations. Jejunal zinc absorption expressed as nmol/intestinal surface was higher in the ethanol-folic acid group than in ethanol animals at all assayed concentrations except at 25 microM concentration. In the second set of experiments, distal ileum zinc absorption in the offspring of ethanolfolic acid dams showed a significant increase at all concentrations tested. These results indicate that supplementation of folic acid and amino acids to dams that consume ethanol during gestation and lactation increase serum and milk zinc levels, although the zinc ingestion is lower. In pups of the supplemented dams, the jejunal and ileal absorption of zinc increased; as a consequence, the serum zinc levels increased. The activity of alcohol dehydrogenase, a metaloenzyme dependent on zinc levels, also increased.     

A longitudinal study of pre- and post-weaning tail damage in non-docked pigs

Tail-biting occurs pre-weaning, but literature on tail damage during lactation and on the development of damage over time is sparse, especially for non-docked piglets. We assessed the prevalence of tail damage in non-docked piglets in a commercial Danish piggery during the lactation and weaning period, and investigated the within-animal association of tail lesions pre- and post-weaning. Non-docked piglets (n = 741) from 51 loose-housed sows were individually marked and tracked from birth to 9 weeks (w9) of age. Tail damage was scored during lactation at w1 and w4, and once a week post-weaning (average weaning age 30 days) at w6 to w9. The within-animal association of tail damage before and after weaning was investigated at pig level using generalized mixed models. Tail damage was prevalent already pre-weaning. During the lactation period, the prevalence of tail lesions was 5% at w1 and 42% at w4, with the most prevalent score being ‘superficial damages’ (66.7%, score 1; pre-weaning scheme: 0 = no damage, 3 = tail wound). Post-weaning, 45% of pigs had a tail lesion at least once over the four assessments, with 16.7% of pigs having a tail lesion at least at two assessments. The majority of lesions were ‘minor scratches’ (34.2%, score 1; post-weaning scheme: 0 = no damage, 4 = wound – necrotic tail end) and a ‘scabbed wound’ (19.9%, score 3). The number of pigs with lesions as well as wound severity increased over time. More pigs had a tail wound at w8 (15%, P < 0.001 and < 0.01) and w9 (19%, P < 0.001 and < 0.001) compared to w6 (2.7%) and w7 (5.6%). Pigs with tail lesions pre-weaning (w1: OR 3.0, 95% CI 0.9 to 10.2; w4: OR 3.4, 95% CI 2.0 to 5.8) had a significantly higher risk of having a wound post-weaning, and pigs with lesions at w4 additionally were at a higher risk (OR 3.0, 95% CI 1.8 to 5.1) of having a lesion over several assessments. Females compared to castrated males had a significantly lower risk of having tail lesions at w1 (OR 0.3, 95% CI 0.1 to 0.8). Similarly, females were at a significantly lower risk (OR 0.5, 95% CI 0.4 to 0.9) of having a wound post-weaning, and tended to have a lower risk of having lesions over several assessments (OR 0.7, 95% CI 0.5 to 1.2). Our study confirmed that tail damage is prevalent already during the lactation period, and that pre-weaning tail damage is predictive of tail wounds post-weaning.     

Sexual Dimorphism of the Feto-Placental Phenotype in Response to a High Fat and Control Maternal Diets in a Rabbit Model

Maternal environment during early developmental stages plays a seminal role in the establishment of adult phenotype. Using a rabbit model, we previously showed that feeding dams with a diet supplemented with 8% fat and 0.2% cholesterol (HH diet) from the prepubertal period and throughout gestation induced metabolic syndrome in adult offspring. Here, we examined the effects of the HH diet on feto-placental phenotype at 28 days post-coïtum (term = 31days) in relation to earlier effects in the blastocyst (Day 6). At 28 days, both male and female HH fetuses were intrauterine growth retarded and dyslipidemic, with males more affected than females. Lipid droplets accumulated in the HH placentas’ trophoblast, consistent with the increased concentrations in cholesteryl esters (3.2-fold), triacylglycerol (2.5-fold) and stored FA (2.12-fold). Stored FA concentrations were significantly higher in female compared to male HH placentas (2.18-fold, p<0.01), whereas triacylglycerol was increased only in HH males. Trophoblastic lipid droplet accumulation was also observed at the blastocyst stage. The expression of numerous genes involved in lipid pathways differed significantly according to diet both in term placenta and at the blastocyst stage. Among them, the expression of LXR-α in HH placentas was reduced in HH males but not females. These data demonstrate that maternal HH diet affects the blastocyst and induces sex-dependent metabolic adaptations in the placenta, which appears to protect female fetuses from developing severe dyslipidemia.     

Effects of birth weight and maternal dietary fat source on the fatty acid profile of piglet tissue

This study aimed to investigate the effects and possible interactions of birth weight and n-3 polyunsaturated fatty acid (PUFA) supplementation of the maternal diet on the fatty acid status of different tissues of newborn piglets. These effects are of interest as both parameters have been associated with pre-weaning mortality. Sows were fed a palm oil diet or a diet containing 1% linseed, echium or fish oil from day 73 of gestation. As fish oil becomes a scarce resource, linseed and echium oil were supplemented as sustainable alternatives, adding precursor fatty acids for DHA to the diet. At birth, the lightest and heaviest male piglet per litter were killed and samples from liver, brain and muscle were taken for fatty acid analysis. Piglets that died pre-weaning had lower birth weights than piglets surviving lactation (1.27±0.04 v. 1.55±0.02 kg; P<0.001), but no effect of diet on mortality was found. Lower DHA concentrations were observed in the brain of the lighter piglets compared with their heavier littermates (9.46±0.05 v. 9.63±0.04 g DHA/100 g fatty acids; P=0.008), suggesting that the higher incidence of pre-weaning mortality in low birth weight piglets may be related to their lower brain DHA status. Adding n-3 PUFA to the sow diet could not significantly reduce this difference in DHA status, although numerically the difference in the brain DHA concentration between the piglet weight groups was smaller when fish oil was included in the sow diet. Independent of birth weight, echium or linseed oil in the sow diet increased the DHA concentration of the piglet tissues to the same extent, but the concentrations were not as high as when fish oil was fed.     

Effects of consuming endophyte-infected tall fescue on growth, reproduction and lactation in mice selected for high fecundity

Effects of a diet containing endophyte-infected tall fescue seed (83% infected) were investigated using 2 lines of mice, one line selected for fecundity (L(+)) and the other a randomly selected control line (K). Treatments included a commercial stock diet (C), 50% stock plus 50% non-infected tall fescue seed (N), and 50% stock plus 50% infected tall fescue seed (I). The experiment was conducted using mice on respective treatments in 2 phases (successive generations), with 15 to 23 mated females per line and diet subgroups. Mated females of Phase 1 were assigned at random within line to experimental diets which were fed during gestation and through 21 d of lactation. Litters were standardized to 10 pups 1 d after birth. Stock diets were fed to all groups from Day 21 to weaning on Day 28. Weaned male and female pups were allotted to previous diets. Mated females in Phase 2 were managed as in Phase 1 through weaning at 28 d. Diets of males did not affect reproduction and data were pooled within female diets. Selected (L(+)) dams gave birth to more live pups than K dams (P<0.05) during both phases (+3.4 and +2.8 +/- 0.4 pups, respectively). Diet but not line affected littering rate of mated females in Phase 1 (71.3%, I; < 87.1%, C or 93.0%, N; P<0.05) and Phase 2 (82.1%, I < 93.8%, N or 97.1%, C; P<0.05). Diet had no effect on fecundity during Phase 1 but females on I diet had reduced (P<0.05) litter size by 1.9 and 3.2 +/- 0.5 pups compared with the females on N and C diets, respectively, in Phase 2. Feed consumption and weights of dams during lactation generally ranked C>N>I. Growth of pups during both phases also ranked C>N>I. Vaginal opening at 28 d differed by line (71.4%, K < 89.3%, L(+), P<0.05) and diet (56.8%, I < 92.0%, C or 92.2%, N, P<0.05). These results suggest both acute and chronic effects of consumption of endophyte-infected diets. Absence of line-by-diet interactions demonstrates that adverse effects were unrelated to genetic differences between lines.     

Exposure to lard-based high-fat diet during fetal and lactation periods modifies breast cancer susceptibility in adulthood in rats

The present study investigated whether early life exposure to high levels of animal fat increases breast cancer risk in adulthood in rats. Dams consumed a lard-based high-fat (HF) diet (60% fat-derived energy) or an AIN93G control diet (16% fat-derived energy) during gestation or gestation and lactation. Their 7-week-old female offspring were exposed to 7,12-dimethyl-benzo[a]anthracene to induce mammary tumors. Pregnant dams consuming an HF diet had higher circulating leptin levels than pregnant control dams. However, compared to the control offspring, significantly lower susceptibility to mammary cancer development was observed in the offspring of dams fed an HF diet during pregnancy (lower tumor incidence, multiplicity and weight), or pregnancy and lactation (lower tumor multiplicity only). Mammary epithelial elongation, cell proliferation (Ki67) and expression of NFκB p65 were significantly lower and p21 expression and global H3K9me3 levels were higher in the mammary glands of rats exposed to an HF lard diet in utero. They also tended to have lower Rank/Rankl ratios (P=.09) and serum progesterone levels (P=.07) than control offspring. In the mammary glands of offspring of dams consuming an HF diet during both pregnancy and lactation, the number of terminal end buds, epithelial elongation and the BCL-2/BAX ratio were significantly lower and serum leptin levels were higher than in the controls. Our data confirm that the breast cancer risk of offspring can be programmed by maternal dietary intake. However, contrary to our expectation, exposure to high levels of lard during early life decreased later susceptibility to breast cancer.