Sow environment during gestation: part I. Influence on maternal physiology and lacteal secretions in relation with neonatal survival

In pig husbandry, pregnant females are often exposed to stressful conditions, and their outcomes on maternal and offspring health have not been well evaluated. The present study aimed at testing whether improving the welfare of gestating sows could be associated with a better maternal health during gestation, changes in the composition of lacteal secretions and improvement in piglet survival. Two contrasted group-housing systems for gestating sows were used, that is, a French conventional system on slatted floor (C, 49 sows) and an enriched system using larger pens on deep straw (E, 57 sows). On the 105^th days of gestation (DG105), sows were transferred into identical farrowing crates on slatted floor. Saliva was collected from all sows on DG35, DG105 and DG107. Blood samples were collected on DG105 from all sows and on the 1^st day of lactation (DL1) from a subset of them (C, n=18; E, n=19). Colostrum and milk samples were collected from this subset of sows at farrowing (DL0) and DL4. Saliva concentration of cortisol was greater in C than in E sows at DG35 and DG105, and dropped to concentrations comparable to E sows after transfer into farrowing crates (DG107). On DG105, plasma concentrations of haptoglobin, immunoglobulins G (IgG) and A (IgA), blood lymphocyte counts and plasma antioxidant potential did not differ between groups (P > 0.10), whereas blood granulocyte count, and plasma hydroperoxide concentration were lower in E than in C sows (P < 0.05). Concentrations of IgG and IgA in colostrum and milk did not differ between the two groups. The number of cells did not differ in colostrum but was greater in milk from E than C sows (P < 0.05). Pre-weaning mortality rates were lower in E than C piglets (16.7% v. 25.8%, P < 0.001), and especially between 12 and 72 h postpartum (P < 0.001). Plasma concentration of IgG was similar in E and C piglets on DL4. In conclusion, differences in salivary cortisol, blood granulocyte count and oxidative stress markers between groups suggested improved welfare and reduced immune solicitation during late gestation in sows of the E compared with the C system. However, the better survival observed for neonates in the E environment could not be explained by variations in colostrum composition.     

Effects of sow nutrition during gestation on within-litter birth weight variation: a review

The increasing demand for efficiency in pork production requires great specialization of all sectors involved in this activity. In this context, the development of strategies that could reduce undesirable traits related with negative effects on piglet survival and postnatal growth and development are essential for the pig industry. Currently, special attention is given to variation in birth weight, as some evidences suggest an increased within-litter birth weight variation in modern sows. This variation has been shown to be associated with preweaning mortality, variable weights at weaning and deteriorated growth performance, which results in economic losses and lower efficiency. Therefore, understanding the factors that can influence the events that occur during gestation and that have an impact on the fetal growth and development are important to achieve better efficiency and also to develop strategies that can be used to achieve increased within-litter uniformity of piglet birth weight. This study concludes that even at a given placental size, fetal growth may vary because of differences in placental vascularization and efficiency. Feeding extra feed or energy during late gestation only marginally improves birth weight, and positive effects are not consistent between different studies. The detrimental effects of protein restriction on fetal growth during early gestation may be due to altered placental and endometrial angiogenesis and growth, which leads to a reduction in placental-fetal blood flow, nutrient supply from mother to the fetuses and ultimately to fetal growth retardation. The number of studies that attempted to influence within-litter birth weight variation by means of sow nutrition during gestation is limited. Therefore, more research concerning sow nutrition during gestation associated with the provision of balanced diets to meet requirements of the sows and fetuses are still required. This knowledge may subsequently provide starting points for the design of nutritional strategies that can influence within-litter birth variation.     

Effect of oral progesterone and caffeine at the end of gestation on farrowing duration and piglet growth and survival

The profitability of pig production is constrained by high incidences of peri-parturient and pre-weaning piglet mortality. Supplementing sows with either progesterone or caffeine during the last week of gestation can reduce stillbirths and improve piglet performance. However, the consequences of combining these two substances has not been investigated. The aim of the current study was to determine the effect of oral supplementation of sows with progesterone (regumate) and caffeine at the end of gestation on the timing and progression of farrowing, as well as piglet survival and growth to weaning. From days 111 to 113 of gestation, 20 Large White pregnant sows (parity 3.0±0.45) received 5 ml of Regumate Porcine (0.4 w/v oral solution; MSD Animal Health) daily on top of their morning ration. Sows were stratified according to parity and predicted farrowing date, and allocated at random to receive a diet supplemented with either 0 g caffeine/kg diet (CONT) or 2.4 g of caffeine/kg diet (CAFF) from day 113 of gestation until parturition (n=10 sows/treatment). Treatment did not affect total litter size; however, CONT sows gave birth to more live and fewer dead piglets compared with CAFF sows; 14.5±0.73 v. 11.7±1.03 and 0.7±0.20 v. 3.2±0.77; P<0.05). Mean, minimum and maximum piglet birthweight were unaffected by treatment. Compared with the control, caffeine increased the proportion of piglets with a birthweight <1 kg (0.16±0.05 v. 0.05±0.02; P=0.072) and decreased the proportion of live born piglets surviving to day 5 postpartum (0.77±0.06 v. 0.90±0.02; P<0.05) and to weaning (0.74±0.06 v. 0.90±0.02; P<0.05). Overall, the current data provided the first evidence that caffeine supplementation of sows receiving progesterone to prevent premature farrowing impaired piglet survival during, and shortly after parturition. This negative outcome may be linked to extended farrowing durations and an increase in the proportion of very light piglets at birth. These data provide compelling, albeit preliminary, evidence that caffeine and progesterone should not be used together at the end of gestation.     

Exogenous genistein in late gestation: effects on fetal development and sow and piglet performance

Due to their functional similarity to estradiol, phytoestrogens could prove to be beneficial in late gestating sows. The goal of this study was to determine the impact of providing the phytoestrogen genistein during late pregnancy on the performance of sows and their litters. In total, 56 gilts were equally divided into the two following groups on day 90 of gestation: (1) controls (CTL); and (2) two daily i.m. injections of 220 mg of genistein (GEN). Treatments were carried out until farrowing. Jugular blood samples were collected from 16 gilts/treatment on days 89 and 110 of gestation, and on days 3 and 21 of lactation. Milk samples were also obtained from those sows on day 3 of lactation. A male piglet from 16 CTL and 15 GEN litters was slaughtered at 24 h postpartum and a blood sample was obtained. The liver, heart and visceral organs were weighed and the semitendinosus (ST) muscle was collected and carcass composition was determined. The treatment increased (P<0.05) the concentrations of genistein and daidzein in the plasma of gilts on day 110 of gestation and of genistein in the plasma of piglets at 24 h postpartum. It also increased IGF1 concentrations in gilts at the end of the treatment period (P<0.05). Genistein had no impact (P>0.1) on weight or backfat loss of sows during lactation, milk composition or weights of piglets. The pre-weaning mortality rate of piglets was very low (<7%), yet the odds ratio comparing CTL with GEN sows indicated almost twice as many chances of pre-weaning deaths occurring in litters from CTL than GEN sows. Weights of the piglet carcasses were similar for both treatments, as well as weights of the various organs and of the ST muscle (P>0.1). However, carcasses from GEN litters contained more fat than those from CTL litters (9.63% v. 8.34%, P<0.05). None of the biochemical properties of the ST muscle differed between groups (P>0.1). In conclusion, injecting gilts with 440 mg/day of genistein in late gestation increased IGF1 concentrations in gilts and carcass fat in neonatal piglets, but had minimal effect on muscle development of piglets at birth and on the performance of lactating sows and their litters.     

Effects of an autocorrelated stochastic environment and fisheries on the age at maturity of Chinook salmon

Chinook salmon (Oncorhynchus tshawytscha) reproduce only once in their lifetime, and their age at reproduction varies among individuals (indeterminate semelparous). However, the factors that determine their spawning age still remain uncertain. Evidence from recent studies suggests that individual growth and reproduction of Chinook salmon are affected by the rate of coastal upwelling, which is shown to be positively autocorrelated between years. Therefore, the serially autocorrelated environmental is expected to play an important role in determining their spawning age. In the present study, I demonstrate the advantage of an indeterminate maturation strategy under a stochastic environment. I then present theoretical evidence for the advantage of adjusting the maturation probability based on the environment they experienced and demonstrate that fisheries reduce the fitness of the strategy to delay maturation. The results presented herein emphasize the importance of incorporating detailed life-history strategies of organisms when undertaking population management.     

Age at maturity in cavies and guinea-pigs (Cavia aperea and Cavia aperea f. porcellus): influence of social factors

Age at maturity, a particularly important parameter in the life history of small mammals, contributes greatly to fitness. Social influences on age at maturity have been demonstrated for altricial rodents, in particular, mice. Nothing is known about such effects in precocial small mammals. Wild cavies Cavia aperea are born in a highly precocial state and mature early in life, briefly after weaning. We investigated whether the wild cavy C. aperea and the domestic guinea-pig Cavia aperea f. porcellus reach maturity earlier in the presence of adults of the opposite sex. Juvenile females kept in pairs without males showed first vaginal opening (=oestrus) when 59 days old in cavies and at about 40 days in the guinea-pig. However, in the company of adult males, cavy females kept in pairs reached maturity when about 30 days old, and guinea-pig females when 26 days old. Most cavy females experienced successful pregnancy following first vaginal opening. In cavies, female mass at birth and at first oestrus was not correlated with age at first oestrus. In guinea-pigs, birth mass predicted age at maturity only when a male was present. The growth rate from birth to first oestrus related to age at first oestrus. In the wild cavy, the presence of a male appeared to influence maturation more between days 25 and 30 than earlier in life. Male C. aperea matured and had fully descended testes when about 65–70 days old. All male cavies produced abundant motile sperm from day 75. First successful copulations occurred at about the same age. Surprisingly, the priming effect of the presence of an adult male on female maturation proved stronger in these highly precocial caviomorphs than in altricial rodents investigated so far.     

Influence of oligosaccharides on the growth and tolerance capacity of lactobacilli to simulated stress environment

Aims:  Lactobacilli should resist stress environments in industry process and gastrointestinal tract before exerting their beneficial effects. To explore the possible stabilizers in probiotic products, prebiotic oligosaccharides were investigated.
Methods and Results:  We investigated the effect of four selected oligosaccharides on the survival of probiotic Lactobacillus plantarum and L. acidophilus to simulated stress conditions. It was found that the tolerance of lactobacilli to simulated artificial gastrointestinal juice, heat treatment and phenol solution was obviously enhanced in fructo-oligosaccharides (FOS) and xylo-oligosaccharides (XOS) group. In addition, chito-oligosaccharides (COS), manno-oligosaccharides (MOS) and glucose also had positive effect compared with control group (without sugar).
Conclusions:  Prebiotic oligosaccharides, especially XOS and FOS added in medium have protection function to lactobacilli in stress environments. The protection function of oligosaccharides may correlate with the bacteria growth, which was stimulated by these oligosaccharides.
Significance and Impact of the Study:  Prebiotic oligosaccharides may be used as stabilizers in probiotic products.     

Ecophysiological responses of Fagus sylvatica seedlings to changing light conditions. II. The interaction of light environment and soil fertility on seedling physiology

The survival and growth of natural beech regeneration after canopy removal is variable and little is known about ecophysiological mechanisms of these responses. Biomass, nonstructural carbohydrate levels and nitrogen concentrations were measured in an Italian population of European beech seedlings. Seedlings were container-grown in two types of soil, organic and mineral, collected at the study site. The seedlings were grown under three light treatments: under full beech canopy (understory), exposed to full sun only during midday (gap) and under full sun (clearing). Leaf gas exchange and chlorophyll a fluorescence parameters were measured and then foliar analyses were conducted for chlorophyll, phenolic and tannin levels. Biomass and allocation were significantly affected by light and soil treatments. The clearing seedlings and those in organic soil were larger than seedlings in the other light treatments or soil type. Total nonstructural carbohydrate concentrations were lower in the understory seedlings and significant differences between soil types were present in the gap and clearing seedlings. Nitrogen concentrations were higher in the understory seedlings and those growing in the organic soil compared to the other treatments. Gas exchange rates were highest in clearing and the organic soil seedlings. Gap seedlings exhibited photosynthetic acclimation that allowed them to utilize high light of midday and any sunflecks during the morning and afternoon. Relative fluorescence was significantly influenced by both light treatment and soil type, with the highest values observed in the gap seedlings. Light response curves showed decreasing apparent maximum quantum efficiency from the understory to clearing, while maximum photosynthetic rate was highest in the gap seedlings. Chlorophyll concentration was highest in understory seedlings and those growing in organic soil and higher in seedlings growing in organic than in mineral soil. Both foliar tannin and phenolic levels were highest in clearing seedlings, and only tannin concentrations were affected by soil type. Understory seedlings had the highest mortality and insect herbivory; the latter was found to be inversely related to tannin concentration. Overall, growth and photosynthesis in beech seedlings responded positively to high light associated with small canopy gaps. Organic soil increased seedling size, particularly in the gap and clearing environments. We conclude that forest gaps are favorable for photosynthesis and growth of European beech seedlings.     

气候变暖可能对东北三省农业生态环境的影响及其对策

随着未来气候变暖,我国东北三省农业生态环境可能发生较大的变化,其变化趋势为,热量条件变好,作物生育期延长,冷害频率降低,积雪期缩短,湿润条件变差,干旱频率增大,蒸发量增加。未来气候变暖,若平均气温升高2℃,那时东北三省粮食产量可增加36%左右,农业地带将大幅度地向北推移,并且提出相应的农业对策。     

Gonadotropin-releasing hormone effects on placental hormones during gestation: II. Progesterone, estrone, estradiol and estriol

The release of progesterone (P), estrone (E1), estradiol (E2) and estriol (E3) from human placental tissue in vitro was found to be related to the gestational age of the placenta. The basal release of P, E1 and E2 on Day 1 of culture was highest from placentas of early gestation (9-13 wk). The release of P then declined, reaching a nadir by 15 wk, and continued at that level. The release of E1 and E2, reached a nadir at 17 weeks, and then again increased by term. In contrast, the basal release of E3 increased with increasing gestational age of the placenta. Thus, it appears that differing factors may influence placental P, E1, E2 and E3 production. In addition, the effect of synthetic gonadotropin-releasing hormone (GnRH) on these hormonal releases was studied. The stimulation of P by GnRH was greatest in placentas of 16 and 17 wk of gestation after extended culture when the basal release of P had declined. As much as a 240-fold increase was observed on the eighth day of culture. A large stimulation of P (32-fold) was also observed in the term placental cultures. A stimulation of E1 and E2 by GnRH was observed during the initial days of culture and in mid-gestational placental cultures (16-17 wk). A stimulation of E2 only was also observed at 13-15 wk and at term. A stimulation of E3 was observed in certain individual placentas. A correlation of the P and human chorionic gonadotropin (hCG) response to GnRH stimulation was noted, as well as an inverse relation of estrogens and hCG stimulation by GnRH. These data demonstrate that steroidogenic competence of the placenta differs with gestational age and that GnRH can influence steroid release. The degree and pattern of response to GnRH varied with the gestational age of the placenta and its endocrine milieu.     

A field experiment on the effects of interspecific competition from roach, Rutilus rutilus (L.), on age at maturity and gonad size in perch, Percafluviatilis L.

The effects of interspecific competition from roach on gonad development in O+ and 1+ perch were studied in a pond experiment by varying the roach density between treatments. The proportion of mature O+ males first increased and, thereafter, decreased with increasing roach density and increasing somatic weight. O f females were immature and all I+ males were mature. The proportion of mature 1+ females decreased with increasing roach density and decreasing somatic weight. The gonad weight of O+ and 1+ males as well as 1+ females decreased with increasing roach density and decreasing somatic weight. For 1+ males, which were individually marked, both start weight as well as somatic end weight were positively related to gonad weight. One possibleexplanation for the hump shaped relationship between the proportion of mature O+ males and somatic weight is that behavioural interactions between O+ and I+ males in the absence of roach affected maturing in O+ males. This study supports previous suggestions that annual variation in resource availability may give rise to variance in fecundity-body size relationships.     

Influence of chronic stress before and/or during gestation on pregnancy outcome of young and old Uje: WIST rats.

Young (70-120 d) and old (11-13 month) Uje:WIST rats were exposed to the strong stressor "chronic restraint" before and/or during gestation. Most adverse effects on pregnancy outcome were induced in young dams stressed before and during gestation (prolonged duration of pregnancy, lower body mass of the newborn pups). In old dams chronic restraint did not further deteriorate the age-dependent poor reproductive performance, but even rejuvenated it, if stress exposure was limited to the premating period.     

Gene–environment interactions at the FKBP5 locus: sensitive periods,mechanisms and pleiotropism

Psychiatric phenotypes are multifactorial and polygenic, resulting from the complex interplay of genes and environmental factors that act cumulatively throughout an organism's lifetime. Adverse life events are strong predictors of risk for a number of psychiatric disorders and a number of studies have focused on gene–environment interactions (GxEs) occurring at genetic loci involved in the stress response. Such a locus that has received increasing attention is the gene encoding FK506 binding protein 51 (FKBP5), a heat shock protein 90 cochaperone of the steroid receptor complex that among other functions regulates sensitivity of the glucocorticoid receptor. Interactions between FKBP5 gene variants and life stressors alter the risk not only for mood and anxiety disorders, but also for a number of other disease phenotypes. In this review, we will focus on molecular and system‐wide mechanisms of this GxE with the aim of establishing a framework that explains GxE interactions. We will also discuss how an understanding of the biological effects of this GxE may lead to novel therapeutic approaches .     

Resveratrol opposite effects on rat tissue lipoperoxidation: pro-oxidant during day-time and antioxidant at night

Abstract

We investigated the dosing-time dependency of acute resveratrol administration on lipoperoxidation level found in the heart, liver and kidney of male rats synchronized with a 12-h dark-light cycle. Resveratrol was administered by the i.p. route at the middle of the dark (6 h after dark onset, HADO) or light span (18 HADO) and thiobarbituric acid reactive species (TBARS) measured 4 h later at 10 and 22 HADO, respectively. Basal TBARS levels in the three organs were higher during the night span when compared to day span. Resveratrol effect on tissues TBARS was also dosing-time dependent. When administered during the dark phase, resveratrol decreased TBARS levels whereas at the light span, the polyphenol increased TBARS in the three organs. Resveratrol behaved as an antioxidant during the dark span and as a pro-oxidant during the light span. These data suggested a day/night rhythm in basal lipoperoxidation and in resveratrol antioxidant effect.     

Grazing in a porous environment: 1. The effect of soil pore structure on C and N mineralization

The porous soil environment constrains grazing of microorganisms by microbivorous nematodes. In particular, at matric potentials at which water-filled pore spaces have capillary diameters less than nematode body diameters the effect of grazing, e.g. enhanced mineralization, should be reduced ('exclusion hypothesis') because nematodes cannot access their microbial forage. We examined C and N mineralization, microbial biomass C (by fumigation-extraction), the metabolic quotient (C mineralization per unit biomass C), nematode abundance, and soil water content in intact soil cores from an old field as a function of soil matric potential (−3 to −50 kPa). We expected, in accordance with the exclusion hypothesis, that nematode abundance, N and C mineralization would be reduced as matric potential decreased, i.e. as soils became drier. N mineralization was significantly greater than zero for −3 kPa but not for −10, −20 and −50 kPa. Microbial biomass C was less at −50 kPa than at −10 kPa, but not significantly different from biomass C at −3 and −20 kPa. The metabolic quotient was greatest at −50 kPa than any of the other matric potentials. From the exclusion hypothesis we expected significantly fewer nematodes to be present at −50 and −20 kPa representing water-filled capillary pore sizes less than 6 and 15 μm, respectively, than at −3 and −10 kPa. Microbivorous (fungivorous+bacterivorous) nematode abundance per unit mass of soil was not significantly different among matric potentials. Body diameters of nematodes ranged from 9 μm to 40 μm. We discuss several alternatives to the exclusion hypothesis, such as the 'enclosure hypothesis' which states that nematodes may become trapped in large water-filled pore spaces even when capillary pore diameters (as computed from matric potential) are smaller than body diameters. One of the expected outcomes of grazing in enclosures is the acceleration of nutrient cycling. This revised version was published online in June 2006 with corrections to the Cover Date.     

A study on body temperature regulation and residential thermal environments of the elderly—II. residential thermal environments at the kansai district

1. 1. An investigation was carried out on 3 male and 4 female elderly people, from 65 to 78 years ol.d The first survey was made in August and September of 1990 (in summer) and the second in January and February of 1991 (in winter).

2. 2. Matters for investigation were human subjects and thermal environmental elements of houses which were recorded by a portable thermo-recorder and a vinyl resin globe thermometer. Dry bulb temperatures at a height of 0.1 and 1.2 m and wet bulb and globe temperatures at 1.2 m high were recorded in the living room, bedroom, toilet etc., the thermo-recorders which measured air and wet bulb temperatures were kept out of the sun.

3. 3. Data was recorded constantly for 7 days at 20 min intervals. Plans of houses and furniture arrangement which influence the thermal conditions were drawn from video recordings. Physical and psychological surveys of individuals were carried out over 2 days of daily life.

4. 4. Subjects carried the thermo-recorders (YM1, YM2) on their side. Rectal, back of hand, sole of foot and ambient temperatures were measured every 2 min and with thermistor sensors. At the same time, behaviour and clothes, assessment of thermal sensation, comfort sensation and sensation of estimated room temperature were reported.

5. 5. Thermal radiation was measured with thermographs during the winter. Human activity was recorded every minute for 33 h. This report is the result of surveys in summer and winter.

6. 6. The following results were obtained: (i) the air conditioning is used sometimes in the houses of the elderly; (ii) thermal sensation range reported is narrow; (iii) skin surface temperatures of the elderly are relatively high and their range of change is narrow, and the range of rectal temperature in a day is narrow; (iv) high activity and excessive heating cause a rise of rectal temperature and the rectal temperatures are lower at rest time.

Effects of resource variation during early life and adult social environment on contest outcomes in burying beetles: a context-dependent silver spoon strategy?

Good early nutritional conditions may confer a lasting fitness advantage over individuals suffering poor early conditions (a ‘silver spoon’ effect). Alternatively, if early conditions predict the likely adult environment, adaptive plastic responses might maximize individual performance when developmental and adult conditions match (environmental-matching effect). Here, we test for silver spoon and environmental-matching effects by manipulating the early nutritional environment of Nicrophorus vespilloides burying beetles. We manipulated nutrition during two specific early developmental windows: the larval environment and the post-eclosion environment. We then tested contest success in relation to variation in adult social environmental quality experienced (defined according to whether contest opponents were smaller (good environment) or larger (poor environment) than the focal individual). Variation in the larval environment influenced adult body size but not contest success per se for a given adult social environment experienced (an ‘indirect’ silver spoon effect). Variation in post-eclosion environment affected contest success dependent on the quality of the adult environment experienced (a context-dependent ‘direct’ silver spoon effect). By contrast, there was no evidence for environmental-matching. The results demonstrate the importance of social environmental context in determining how variation in nutrition in early life affects success as an adult.