Small Litters Research Articles

Preconception Prebiotic and Sitagliptin Treatment in Obese Rats Affects Pregnancy Outcomes and Offspring Microbiota, Adiposity, and Glycemia.

Maternal obesity is associated with increased risk of pregnancy complications and greater risk of obesity in offspring, but studies designed to examine preconception weight loss are limited. The objective of this study was to determine if a combined dietary [oligofructose (OFS)] and pharmacological (sitagliptin) preconception intervention could mitigate poor pregnancy outcomes associated with maternal obesity and improve offspring metabolic health and gut microbiota composition. Diet-induced obese female Sprague-Dawley rats were randomized to one of four intervention groups for 8 weeks: (1) Obese-Control (consumed control diet during intervention); (2) Obese-OFS (10% OFS diet); (3) Obese-S (sitagliptin drug); (4) Obese-OFS + S (combination treatment). Two reference groups were also included: (5) Obese-HFS (untreated obese consumed high fat/sucrose diet throughout study); (6) Lean-Control (lean reference group that were never obese and consumed control diet throughout). Offspring consumed control diet until 11 weeks of age followed by HFS diet until 17 weeks of age. The Obese-OFS + S rats lost weight during the intervention phase whereas the OFS and S treatments attenuated weight gain compared with Obese-HFS (p < 0.05). Gestational weight gain was lowest in Obese-OFS + S rats and highest in Obese-HFS rats (p < 0.05). Prepregnancy intervention did not affect reproductive parameters but did affect pregnancy outcomes including litter size. Male Obese-OFS offspring had significantly lower percent body fat than Obese-HFS at 17 weeks. Female Obese-S and Obese-OFS offspring had significantly lower fasting glucose at 17 weeks compared with Obese-Control and Obese-HFS. Clostridium cluster XI was higher in Obese-HFS and Obese-S dams at birth compared with all other groups. Dams with an adverse pregnancy outcome had significantly lower (p = 0.035) Lactobacillus spp. compared with dams with normal or small litters. At weaning, male offspring of Obese-HFS had higher levels of Methanobrevibacter than all other groups except Obese-S and female Obese-HFS offspring had higher Enterobacteriaceae compared with all other groups. At 11 and 17 weeks of age, Bacteroides/Prevotella spp. was significantly lower in male and female offspring of Obese-HFS dams compared with all other groups except Obese-OFS + S. Modest weight loss induced with a diet-drug combination did not affect maternal fecundity but did have sex-specific effects on offspring adiposity and glycemia that may be linked to changes in offspring microbiota.

Epidemiology of clinical feline herpesvirus infection in zoo-housed cheetahs (Acinonyx jubatus).

OBJECTIVE To determine the incidence of and risk factors for clinical feline herpesvirus (FHV) infection in zoo-housed cheetahs and determine whether dam infection was associated with offspring infection. DESIGN Retrospective cohort study. ANIMALS 144 cheetah cubs born in 6 zoos from 1988 through 2007. PROCEDURES Data were extracted from the health records of cheetahs and their dams to identify incident cases of clinical FHV infection and estimate incidence from birth to 18 months of age. Univariate and multivariable Cox proportional hazards models, controlling for correlations among cheetahs with the same dam, were used to identify risk factors for incident FHV infection. RESULTS Cumulative incidence of FHV infection in cheetah cubs was 35% (50/144). No significant association between dam and offspring infection was identified in any model. Factors identified as significant through multivariable analysis varied by age group. For cheetahs up to 3 months of age, the most important predictor of FHV infection was having a dam that had received a preparturition FHV vaccine regimen that included a modified-live virus vaccine versus a dam that had received no preparturition vaccine. Other risk factors included being from a small litter, being born to a primiparous dam, and male sex. CONCLUSIONS AND CLINICAL RELEVANCE This study provided the first population-level characterization of the incidence of and risk factors for FHV infection in cheetahs, and findings confirmed the importance of this disease. Recognition that clinical FHV infection in the dam was not a significant predictor of disease in cubs and identification of other significant factors have implications for disease management.

Effects of postnatal overfeeding and fish oil diet on energy expenditure in rats.

BackgroudEarly life nutrition may have a role in the regulation of metabolism in adulthood. The present study aimed to evaluate the effects of postnatal overfeeding and a postweaning fish oil diet on energy expenditure.MethodsOn postnatal day 3, rat litters were adjusted to a litter size of three (small litters, SLs) or ten (normal litters, NLs). After weaning, SLs were fed the standard diet or a fish oil diet enriched with polyunsaturated fatty acids (SL-FOs) for 10 weeks. The metabolic parameters of rats were monitored using the TSE LabMaster at postnatal week 3 (W3) and postnatal week 13 (W13).ResultsAt W3, the O2 consumption and heat production in SLs were lower than those in NLs, while the respiratory exchange ratio (RER) was higher than NLs. SLs showed obesity, dyslipidemia, and impaired glucose tolerance at W13. The postweaning fish oil diet in SLs not only increased O2 consumption, CO2 production, heat production, and reduced the RER but it also reduced weight gain, serum triglycerides, and improved glucose tolerance at W13.ConclusionPostnatal overfeeding can decrease the level of body energy expenditure and induce obesity, but a fish oil diet can increase the energy expenditure and prevent the development of metabolic dysregulation in adults.

On the technological development of cotton primary processing, using a new drying-purifying unit

The article reflects feasibility study of conducting research on technological development of cotton primary processing with the modified parameters of drying and cleaning process for small litter. As a result of theoretical and experimental research, drying and purifying unit is designed, in which in the existing processes a heat source, exhaust fans, a dryer drum, a peg-drum cleaner of cotton and the vehicle transmitting raw cotton from the dryer to the purifier will be excluded. The experience has shown that when a drying-purifying unit is installed (with eight wheels) purifying effect on the small litter of 34%, ie cleaning effect is higher than of that currently in operation 1XK drum cleaner. According to the research patent of RU UZ FAP 00674 “Apparatus for drying and cleaning fibrous material” is received.

Effects of birth weight and standardized litter size on growth performance of boars and subsequent reproductive performance

The aim of this study was to investigate the effects of birth weight and rearing litter size on growth and reproductive performance of boars. One hundred and forty male piglets were allotted to two groups, based on litter size: a smaller litter (SL) (8 piglets/litter, 70 boars) and a larger litter (LL) (12 piglets/litter, 70 boars). The boars in these litters were separated into two birth weight subgroups: lower birth weight (LBW) (mean: 1.15 kg, 70 boars) and greater birth weight (GBW) (mean: 1.59 kg, 70 boars). Testes volume, sexual activity and semen quality of boars at 180 days old were evaluated. The males in the GBW group, when compared with the LBW group, had greater bodyweight at 21, 28, and 63 days old ( P <0.01) and 180 days old ( P <0.05), greater testes volume and semen volume ( P <0.05), greater sperm concentration and total number of sperm in the semen ( P <0.01) and a longer ejaculation time ( P <0.05). The boars in the SL group had greater ( P <0.01) bodyweight at 21 and 28 days old, greater ( P <0.05) sperm concentration and total number of sperm in the semen than boars in the LL group. These results indicate that birth weight is a good predictor of sperm production in adult boars and suggest the possibility of increasing sperm production in adult boars by reducing the litter size in which they are reared. Keywords: Boars, bodyweight, piglets, reproduction, semen

Effect of litter size on pre-pubertal body weight and testicular volume in crossbred boars

The objective of this study was to examine the effect of litter size on pre-pubertal body weight and testicular volume in crossbred (Landrace × Desi) boars. The body weights of the piglets in small litter were significantly higher than large litter, at all age except weaning. At 22 weeks of age, boar reared in small litter was 10 kg heavier than larger litter. The testicular volume was significantly higher in all the piglets of small litter than piglets of larger litter at 18 and 22 weeks. However, at 14 weeks, piglets of small litter showed a tendency of higher testicular volume than the piglets of larger litter size. The results of this study suggest that piglets born and reared with small litter size are beneficial to obtain higher body weight and testicular volume around puberty. This may be helpful in early selection of boars for future use in artificial insemination.

Abstract P302: Nicotinamide Ameliorates IgA Nephropathy and Pregnancy Outcome in Pregnant Grouped-ddy Mice

Objective: IgA nephropathy (IgAN) affects women in childbearing ages. We have reported that nicotinamide (Nam) ameliorates a preeclampsia (PE)-like condition and pregnancy outcome in PE mouse models ( PNAS 2016, AJP 2017). Our preliminary data show that pregnant grouped ddY (gddY) mice, a model of IgAN, have PE-like phenotype and adverse pregnancy outcome. The aim of the present study is to clarify whether Nam ameliorates IgAN and pregnancy outcome in pregnant gddY mice. Design and Method: Pregnant gddY mice 9-11 weeks of age were divided into four groups (gddY, gddY+Nam, gddY+sFlt-1, and gddY+sFlt-1+Nam). PE-like phenotype was induced by administering sFlt-1 adenovirus (4x10 8 pfu) at 14.5 dpc. Nam 500 mg/kg/day was administered daily using gavage from 12.5 dpc. Age-matched pregnant slc:ddY mice were used as a control. Results: Compared with control ddY mice, gddY mice showed higher SBP and urinary albumin excretion (Fig. 1), and smaller litter size and fetal weights. Moreover, gddY+sFlt-1 mice showed severe endotheliosis and poor pregnancy outcome. Nam alleviated hypertension, albuminuria (Fig. 1), mesangial expansion and endotheliosis in gddY and gddY+sFlt-1 mice. In addition, Nam prolonged pregnancy period of gddy+sFlt-1 mice. Fetal weights from gddY+Nam mice, and gddY+sFlt-1+Nam mice were larger than those of gddY and gddY+sFlt-1 mice. Conclusions: Nam alleviated maternal hypertension, proteinuria and fetal growth restriction in pregnant gddY and gddY+sFlt-1 mice. Nam could help treat maternal IgAN with pregnancy and PE with IgAN.

Did Panthera pardus (Linnaeus, 1758) become extinct in Sumatra because of competition for prey? Modeling interspecific competition within the Late Pleistocene carnivore guild of the Padang Highlands, Sumatra

On the Island of Sumatra, the leopard (Panthera pardus) became extinct during the Late Pleistocene. Several theories exist about the reasons why leopards could not subsist in Sumatra, while today, national parks still bear tigers (Panthera tigris) and Asiatic wild dogs (Cuon alpinus). One often debated theory is that the competition for prey was the reason for the extinction of leopards in Sumatra. The aim of our study is to model the impacts of competition for prey in the carnivore guild of the Padang Highlands in Sumatra to test if competition pressure was sufficient to force the leopard to extinction. In the first step, we reconstructed the carnivore guild of the Padang Highlands based on fossils collected by Dubois in the three cave sites of Sibrambang, Djamboe and Lida Ajer. In the second step, we developed and applied an agent-based model based on population density, prey spectrum and daily meat intake and simulated different scenarios of competition among the Sumatran predators. We simulated the reconstructed guild and further tested scenarios with the absence of guild members to see under which circumstances leopards could have survived in Sumatra. Simulation of the reconstructed carnivore guild revealed that, in fact, the leopard could have been driven to extinction by competition from other carnivores. Excluding one of the competing medium-sized cats or the Asiatic wild dog leads to the survival of the leopard in our simulations. Interestingly, our model demonstrates that humans and tigers were not the strongest competitors for leopards because their exclusion from the scenarios does not conclude with the survival of leopards in our simulations. According to our results, the presence of two medium-sized cats and the Asiatic wild dog, in combination with the small litter size of the leopard, were the main reasons why the leopard could not tolerate the competition for prey in the Padang Highlands in Sumatra and thus became extinct in Sumatra.

Maternal low intensity physical exercise prevents obesity in offspring rats exposed to early overnutrition

Low intensity exercise during pregnancy and lactation may create a protective effect against the development of obesity in offspring exposed to overnutrition in early life. To test these hypotheses, pregnant rats were randomly assigned into 2 groups: Sedentary and Exercised, low intensity, on a rodent treadmill at 30% VO2Max /30-minute/session/3x/week throughout pregnancy and the lactation. Male offspring were raised in small litters (SL, 3 pups/dam) and normal litters (NL, 9 pups/dam) as models of early overnutrition and normal feed, respectively. Exercised mothers showed low mesenteric fat pad stores and fasting glucose and improved glucose-insulin tolerance, VO2max during lactation and sympathetic activity. Moreover, the breast milk contained elevated levels of insulin. In addition, SL of sedentary mothers presented metabolic dysfunction and glucose and insulin intolerance and were hyperglycemic and hyperinsulinemic in adulthood. SL of exercised mothers showed lower fat tissue accretion and improvements in glucose tolerance, insulin sensitivity, insulinemia and glycemia. The results suggest that maternal exercise during the perinatal period can have a possible reprogramming effect to prevent metabolic dysfunction in adult rat offspring exposed to early overnutrition, which may be associated with the improvement in maternal health caused by exercise.

A synergistic negative effect of gestational smoke-exposure and small litter size on rat placental efficiency, vascularisation and angiogenic factors mRNA expression.

Smoking increases the risk of pregnancy complications such as spontaneous abortion and low birth weight (LBW). By cigarette smoke exposure (gestational day, GD3-17), normal-litter-size pregnancy with low birth weight (NP-LBW) and small-litter-size pregnancy with normal birth weight (SP-NBW) in rats were induced. The placental weight in SP-NBW was twice the weight of the normal in contrast with the smaller placenta in NP-LBW. Compared with the normal, placental efficiency (expressed as fetus-to-placenta weight ratio) and placental vascularisation were significantly decreased in smoke exposed placentas with more obvious decrease in SP-NBW. For NP-LBW, decreased placental vascularisation was due to decreased labyrinth vascularisation which was caused by both decreased number density and diameter of fetal capillary. For SP-NBW, decreased placental vascularisation was due to reduced proportion of labyrinth in placenta and decreased labyrinth vascularisation which was caused by decreased fetal capillary number density. Real time RT-PCR analysis showed a tendency for decreased placental mRNA level of vascular endothelial growth factor (VEGF), angiopoietin-1 (Ang1) and tyrosine kinase receptor-2 (Tie2) in NP-LBW(P<0.1), and the tendency became obvious in SP-NBW(P<0.05). A tendency for decreased placental mRNA level of fms-like tyrosine kinase-1(Flt1) and angiopoietin-2 (Ang2) was also observed in SP-LBW(P<0.1). Our data demonstrated the synergistic negative effect of gestational smoke-exposure and small litter size on placental efficiency, placental vascularisation and placental angiogenic growth factor mRNA expression in rat.

A delayed sperm penetration of cumulus layers by disruption of acrosin gene in rats.

Acrosin, the trypsin-like serine protease in the sperm acrosome, was long viewed as a key enzyme required for zona pellucida penetration to fertilize eggs. However, gene disruption experiments in mice surprisingly showed that acrosin-disrupted males were fertile. Thus, the acrosin was considered to be not an essential enzyme for fertilization in mice. However, the involvement of acrosin in fertilization has been suggested in various species such as rat, bull, and pig. Moreover, it has been reported that serine protease (including acrosin) activity in mice is significantly weaker compared to other species, including rats. We analyzed the role of acrosin by disrupting the rat acrosin gene. It was found that, unlike in mice, acrosin was almost the sole source of serine protease in rat spermatozoa. Nevertheless, the acrosin-disrupted males were not infertile. However, the litter size from acrosin-disrupted males was decreased compared to heterozygous mutant rats. Further investigation using an in vitro fertilization system revealed that the acrosin-disrupted spermatozoa possessed an equal ability to penetrate the zona pellucida with wild-type spermatozoa, but the cumulus cell dispersal was slower compared to wild-type and heterozygous spermatozoa. This delay was presumed to be the cause of the small litter size of acrosin-disrupted male rats.

Mother–young bonding in prolific D’man and Romanov sheep

The effect of prolificacy on mother–young mutual recognition is still largely unknown in sheep. The aim of the present study was to investigate the ability of prolific ewes to develop an exclusive bond with their neonate and to recognize each other from alien subjects. Observations were performed on 11 D’man and 16 Romanov ewes with, respectively, 19 and 37 of their lambs. Maternal selectivity was tested at 24 h postpartum during two consecutive periods of 3 min. All mothers accepted their own lambs at suckling, while 21 out of 27 (78%) rejected the alien, thus displaying mostly selective nursing. To assess mother–young recognition, a two-choice test was performed at 36 h postpartum. Ewes clearly preferred their own lambs to an alien lamb and behavioral differences were not found between mothers of small (singletons and twins) and large litters (triplets and quadruplets). Romanov ewes reached their own lambsmore rapidly and spent more time near them than D’man ewes. Lambs from small litters, in particular light lambs, clearly preferred their mothers to an alien dam; however, both light and heavy lambs in large litters did not discriminate between the two stimulus ewes. D’man lambs clearly preferred their mothers to an alien dam; in contrast, such a preference was not as clearly demonstrated in Romanov lambs.

Niche pork: Comparing pig performance and understanding producer benefits, barriers and labeling interest

AbstractOpportunities for alternative swine production and marketing are emerging across the value chain. Given the developing nature of the differentiated pork industry, measurements of niche performance and success are not yet fully known. For this reason, the objectives of this study were to determine performance metrics across all major life phases for niche pork production and compare such metrics with national averages of conventional commodity pork production. Additionally, this study aimed to quantify producers’ reasoning and barriers to successfully raising niche swine. Niche meat producers in the USA self-identified for this study (n = 176); their swine production had alternative characteristics that included small- to mid-sized farms, farrow-to-finish operations, heritage breeds, housing with bedding and outdoor or pasture access, no use of antibiotics (sub-therapeutic for growth promotion or no antibiotics ever), vegetarian feed, diverse agricultural enterprises and alternative marketing avenues. This study focused on the metric categories regarding reproduction, mortality, culling and growth characteristics. The niche system produced approximately 15% fewer weaned piglets per bred sow per year than the conventional system due to fewer breeding cycles, smaller litters and higher piglet mortality in alternative production. Similarly, niche production finished 12% fewer hogs per bred sow per year than conventional production. Regarding age benchmarks of finishing and breeding, the niche system averaged 18 additional days to finish hogs at a standardized market weight of 124 kg. Likewise, niche production gilts were first bred at 283 days, whereas conventional production breeds gilts at 225 days. All directly comparable metrics were found to be statistically significant with 95% confidence for the one-sample test of means. Regarding farmer attitudes toward niche pork, survey participants shared personal reasons for raising swine and barriers to successful niche production. Choosing niche over commodity swine, participants’ reasons were grouped into three intra-related categories: (1) farm and producer viability, (2) animal and environmental welfare, and (3) consumer preference and taste. Despite these benefits, participants were faced with numerous challenges, which were organized into four intra-related categories: (1) alternative production requirements, restrictions and knowledge; (2) access and affordability of credit and inputs; (3) alternative supply chain for processing, marketing and customers; and (4) non-niche production competition and governmental policies. In sum, the success of these niche pork operations equates to high welfare for the pigs, economic viability for the operation, personal enjoyment for the farmer, customer satisfaction with meat flavor and quality, and responsible environmental practices, inclusive of many components of an alternative food system.

Age-related effects of body mass on fertility and litter size in roe deer.

We analysed effects of females’ body mass and age on reproductive capacity of European roe deer (Capreolus capreolus) in a large sample set of 1312 females (305 yearlings and 1007 adults), hunted throughout Slovenia, central Europe, in the period 2013–2015. Body mass positively affected probability of ovulation and potential litter size (number of corpora lutea), although its effect was more pronounced in yearlings than in adults. Between age groups, we found clear differences in responses of both reproductive parameters to body mass which influences primarily reproductive performance of younger, and in particular, lighter individuals: at the same body mass yearlings would at average have smaller litters than adults, and at lower body mass also young to middle-aged adults would have smaller litters than old ones. In addition, while yearlings have to reach a critical threshold body mass to attain reproductive maturity, adult females are fertile (produce ova) even at low body mass. However, at higher body mass also younger individuals shift their efforts into the reproduction, and after reaching an age-specific threshold the body mass does not have any further effects on the reproductive output of roe deer females. Increased reproductive capacity at more advanced age, combined with declining body mass suggests that old does allocate more of their resources in reproduction than in body condition.

Granulosa cell endothelin-2 expression is fundamental for ovulatory follicle rupture

Ovulation is dependent upon numerous factors mediating follicular growth, vascularization, and ultimately oocyte release via follicle rupture. Endothelin-2 (EDN2) is a potent vasoconstrictor that is transiently produced prior to follicle rupture by granulosa cells of periovulatory follicles and induces ovarian contraction. To determine the role of Edn2 expression, surgical transplant and novel conditional knockout mice were super-ovulated and analyzed. Conditional knockout mice utilized a new iCre driven by the Esr2 promoter to selectively remove Edn2. Follicle rupture and fertility were significantly impaired in the absence of ovarian Edn2 expression. When ovaries of Edn2KO mice were transplanted in wild type recipients, significantly more corpora lutea containing un-ovulated oocytes were present after hormonal stimulation (1.0 vs. 5.4, p = 0.010). Following selective ablation of Edn2 in granulosa cells, Esr2-Edn2KO dams had reduced oocytes ovulated (3.8 vs. 16.4 oocytes/ovary) and smaller litters (4.29 ± l.02 vs. 8.50 pups/dam). However, the number of pregnancies per pairing was not different and the reproductive axis remained intact. Esr2-Edn2KO ovaries had a higher percentage of antral follicles and fewer corpora lutea; follicles progressed to the antral stage but many were unable to rupture. Conditional loss of endothelin receptor A in granulosa cells also decreased ovulation but did not affect fecundity. These data demonstrate that EDN2-induced intraovarian contraction is a critical trigger of normal ovulation and subsequent fecundity.

Administration of Fluoxetine or a Small Molecule TPH1 Inhibitor Affects Litter Size, Pup Mortality, and Milk Yield During Murine Pregnancy and Lactation

Non‐neuronal serotonin regulates milk synthesis in an autocrine‐paracrine manner during lactation. Selective Serotonin Reuptake Inhibitors (SSRI), including Fluoxetine, are the most commonly prescribed antidepressants during pregnancy and lactation in the United States. SSRI increase local activity of serotonin in both neuronal and non‐neuronal tissues, including the mammary gland. The objective of this study was to examine the effects of SSRI administration during lactation on milk yield, pup weight, pup mortality, and litter size. As a negative control, we used a small‐molecule inhibitor of the rate‐limiting enzyme in serotonin synthesis, tryptophan hydroxylase 1 (Tph1). Beginning the day after pregnancy (d1 after cervical plug), C57Bl/6J dams were administered 20 mg/kg of either saline or fluoxetine daily via intraperitoneal injection through d21 of lactation. Additionally, on d1 of pregnancy, dams were either maintained on a control diet or loaded on a control diet fortified with a small‐molecule inhibitor of Tph1. There were three treatment groups: injected with saline and receiving control chow (CON; n=15), fluoxetine/control chow (FLX; n=11), saline/Tph1 inhibitor chow (TPH1; n=14). Litter size on d0 was recorded, as was pup mortality throughout lactation. Milk yield per pup was determined using the weigh‐suckle‐weigh method and pup weight gain was recorded. Of all dams enrolled in the study (19 CON, 34 FLX, 26 TPH1), a certain proportion were excluded because all pups were found dead. By treatment, 21.1% (4/19) of CON dams, 67.6% (23/34) of FLX dams, and 46.2% (12/26) of TPH1 dams were excluded due to a dead/killed litter. Of those dams that kept all pups, FLX dams had smaller litters (P=0.01; 6.5 ± 0.4 vs. 4.6 ± 0.5 vs. 6.4 ± 0.5 pups for CON, FLX, and TPH1) and tended to have more dead pups (P=0.06; 0.7 ± 0.2 vs. 0.9 ± 0.3 vs. 0.2 ± 0.1 dead pups for CON, FLX, and TPH1) than CON or TPH1 dams. FLX dams also produced less milk (P=0.03) than TPH1 or CON dams and subsequently had pups that gained less weight throughout lactation (P&lt;0.0001; 4.9 ± 0.5 vs. 4.4 ± 0.5 vs. 4.7 ± 0.5 g/pup for CON, FLX, and TPH1). Collectively, this data suggests that FLX administration throughout pregnancy and lactation may have adverse effects on pup development both in utero and during lactation. While previous literature has established that SSRI are the safest antidepressants due to minimal side effects, our data suggests that FLX treatment affects the dam's gestational and lactational capacity and therefore pup growth during pregnancy and lactation.Support or Funding InformationKaros PharmaceuticalsNational Science Foundation Graduate Research Fellowship Grant No. DGE‐1256259

Is reproductive strategy of Alpine mountain hares adapted to different elevations?

In Lepus, litter size is inversely related to the duration of the reproductive season resulting in a consistent yearly production of around ten leverets per female. In high latitudes, animals have few litters with large litter sizes, whereas in low latitudes, several litters with small litter sizes are common per year. Knowledge on reproductive performance of Alpine mountain hares (Lepus timidus varronis) is scarce. In this study, we analysed 89 hares from Grisons, Switzerland, by examining placental scars and eye lens weight. The general aim of the survey was to examine the reproductive performance of female Alpine mountain hares. In particular, we focused on the question whether this subspecies adjusts the reproductive strategy in relation to elevation such as other Lepus species do in relation to latitude. All adults of our sample reproduced. 39% of the females littered twice and 61% three times a year with a median litter size of 3.00. We identified a significant effect of elevation on litter size, whereas the elevation did not influence the number of litters. We found no significant difference of yearly reproductive output across elevation range. Hence, some reproductive parameters seem to indicate that the Alpine mountain hare changes the reproductive strategy in relation to elevation similar to the mountain hares living further north do in relation to latitude.

COMPROMISED FERTILITY IN FREE FEEDING OF WILD-CAUGHT NORWAY RATS (RATTUS NORVEGICUS) WITH A LIQUID BAIT CONTAINING 4-VINYLCYCLOHEXENE DIEPOXIDE AND TRIPTOLIDE.

Wild rat pests in the environment cause crop and property damage and carry disease. Traditional methods of reducing populations of these pests involve poisons that can cause accidental exposures in other animals and humans. Fertility management with nonlethal chemicals would be an improved method of rat pest population control. Two chemicals known to target ovarian function in female rats are 4-vinylcyclohexene diepoxide (VCD) and triptolide. Additionally, triptolide impairs spermatogenesis in males. A liquid bait containing no active ingredients (control), or containing triptolide (0.001%) and VCD (0.109%; active) was prepared to investigate the potential use of these agents for wild rat pest population control. Liquid bait was made available to male (n = 8 control; n = 8 active) and female (n = 8 control; n = 8 active) Sprague Dawley rats ( Rattus norvegicus ) for oral consumption prior to breeding. Whereas, control bait-treated females produced normal-sized litters (10.0 ± 1.7 pups/litter), treated females delivered no pups. Wild Norway male (n = 20) and female (n = 20) rats ( Rattus norvegicus ) were trapped, individually housed, and one group given free access to control bait, one group to active bait. Following three cycles of treatment-matched mating pairs, females consuming control bait (control) produced normal litter sizes (9.73 ± 0.73 pups/litter). Females who had consumed active bait (treated) produced no litters on breeding cycles one and two; however, 2 of 10 females produced small litters on the third mating cycle. In a fourth breeding cycle, control females were crossmated with treated males, and treated females were crossmated with control males. In both groups, some dams produced litters, while others did not. The differences in response reflect a heterogeneity in return to cyclicity between females. These results suggest a potential approach to integrated pest management by compromising fertility, and could provide a novel alternative to traditional poisons for reducing populations of wild rat pests.

In Utero Exposure of Hyperlipidemic Mice to Diesel Exhaust: Lack of Effects on Atherosclerosis in Adult Offspring Fed a Regular Chow Diet

Uterine stress is associated with an increased risk of later life metabolic diseases. In this study, we investigated the effect of diesel exhaust (DE) exposure in utero on adult susceptibility to atherosclerosis in genetically hyperlipidemic mice. Pregnant apolipoprotein E-deficient mice received either DE exposure (~250–300 μg/m3 PM2.5 for 6 h/day, 5 days/week) or filtered air (FA) throughout gestation. Treatment effects on litter size and gender distribution were recorded. Plasma cholesterol and triglycerides were measured at 8, 12 and 16 weeks of age. Urinary 8-isoprostane and liver 8-hydroxy-deoxyguanosine levels were measured at killing at 16 weeks of age. Expression of the antioxidant genes heme oxygenase-1 and the glutamate-cysteine ligase modifier and catalytic subunits were measured in the lung, liver and aorta. The average area and frequency of atherosclerotic lesions were measured in the aortic sinus and innominate arteries. There were significantly smaller litters and higher postnatal mortality in the DE-exposed mice. There were no significant differences in plasma lipids or lipoprotein profiles, expression of antioxidant genes or markers of oxidative stress between treatment groups. There were also no significant differences in average atherosclerotic lesion area in the aortic sinus or innominate arteries of the DE and FA groups although there was a higher frequency of lesions in the DE-exposed group. Our study indicates that in utero DE exposure does not influence later life lipoprotein metabolism, redox homeostasis or the risk of developing larger atherosclerotic lesions.

Administration of non-pathogenic isolates of Escherichia coli and Clostridium perfringens type A to piglets in a herd affected with a high incidence of neonatal diarrhoea

A bacterial cocktail of living strains of Clostridium perfringens type A (CPA) without β2-toxin gene and non-pathogenic Escherichia coli was administered orally to newborn piglets before first colostrum intake and on 2 consecutive days on a farm with a high incidence of diarrhoea and antibiotic treatment in suckling piglets associated with E. coli and CPA. This clinical field study was driven by the hypothetic principle of competitive exclusion of pathogenic bacteria due to prior colonization of the gut mucosal surface by non-pathogenic strains of the same bacterial species with the aim of preventing disease. Although CPA strains used in this study did not produce toxins in vitro, their lack of pathogenicity cannot be conclusively confirmed. The health status of the herd was impaired by a high incidence of postpartum dysgalactia syndrome in sows (70%) and a high incidence of neonatal diarrhoea caused by enterotoxigenic E. coli and CPA during the study. No obvious adverse effect of the bacterial treatment occurred. On average, more piglets were weaned in litters treated (P=0.009). Visual pathological alterations in the small intestinal wall were more frequent in dead piglets of the control group (P=0.004) and necrotizing enteritis was only found in that group. A higher average daily weight gain of piglets in the control group (P<0.001) may be due to an increased milk uptake due to less competition in the smaller litters. The bacterial cocktail was tested under field conditions for its potential to stabilize gut health status in suckling piglets before disease development due to colibacillosis and clostridial infections; however, the gut flora stabilizing effect of the bacterial cocktail was not clearly discernible in this study. Further basic research is needed to confirm the positive effects of the bacterial treatment used and to identify additional potential bacterial candidates for competitive exclusion.