Post-weaning Group Research Articles

Metabolic changes before and after weaning in Dezhou donkey foals in relation to gut microbiota.

Weaning is undoubtedly one of the most crucial stages in the growth and development of all mammalian animals, including donkey foals. Weaning is a dynamic and coordinated process of the body, which is closely associated with the health, nutrition, and metabolism of the host. Many studies have shown that the intestinal microbiota and serum metabolites of mammals exhibit different changes during lactation, weaning, and postweaning. However, the alterations in serum metabolites in donkey foals before and postweaning and the correlation between serum metabolites and intestinal microbiota are largely unknown. This study is based on the fecal 16S rRNA and serum metabolomes of Dezhou donkey foals. In total, 10 samples (fecal and serum) were collected during the following three stages: before weaning (F.M.1), during weaning (F.M.3), and postweaning (F.M.6). To study the alterations in intestinal microflora, serum metabolites, and their correlation before and postweaning. We found that with the growth and weaning progress of donkey foals, the intestinal microbiota of donkey foals underwent obvious changes, and the diversity of fecal bacteria increased (Chao1 and Shannon indexes). The main intestinal microbial flora of donkey foals include Bacteroides and Firmicutes. We found many microbiota that are associated with immunity and digestion in the postweaning group, such as Verrucomicrobiales, Clostridia, Oscillospiraceae, Akkermansia, and Rikenellaceae, which can be considered microbial markers for the transition from liquid milk to solid pellet feed. Clostridia and Oscillospiraceae can produce organic acids, including butyric acid and acetic acid, which are crucial for regulating the intestinal microecological balance of donkeys. Furthermore, the metabolome showed that the serum metabolites enriched before and postweaning were mainly related to arachidonic acid metabolism and riboflavin metabolism. Riboflavin was associated with the development of the small intestine and affected the absorption of the small intestine. We also found that the changes in the gut microbiome of the foals were significantly correlated with changes in serum metabolites, including lysophosphatidylcholine (LPC; 12,0) and positively correlated with Lachnoclostridium and Roseburia. To summarize, this study provides theoretical data for the changes in the intestinal microbiome and serum metabolism during the entire weaning period of donkey foals.

The effects of timing of high immune response phenotyping in relation to weaning on immune responses of crossbred beef calves.

Genetic selection for immune response has the potential to increase the sustainability of the beef industry by breeding cattle that are productive yet with an increased capacity to resist disease. Determining the optimal time to immunophenotype beef cattle is crucial for the accurate prediction of an animal's immune response. The objective of this study was to determine the effect of time of immunophenotyping in relation to weaning on immune responses of beef calves. Antibody- (AMIR) and cell-mediated (CMIR) immune responses were measured on 97 calves on the day of weaning (WEANING, N = 56) or 2 mo post-weaning (POST-WEANING, N = 41). Within each period of immunophenotyping, on day 0, blood was collected, and calves received a 1.0 mL intramuscular injection of type 1 and 2 test antigens. On day 14, blood was collected, and baseline skinfold thickness (SFT) was measured. Calves received an intradermal injection of 0.1 mg of the type 1 antigen suspended in 0.1 mL phosphate buffered saline (PBS) in the right tail fold, and 0.1 mL of PBS in the left. Changes in SFT at 24 h was used to indicate CMIR. To assess AMIR, the titer of type 2 antigen-specific bovine immunoglobulin G in serum from blood collected on day 14 was determined by measuring optical density (OD) using an enzyme-linked immunosorbent assay (ELISA). Among heifers, AMIR was greater for the POST-WEANING group than for the WEANING group (P < 0.01). Among steers, AMIR was not different between the POST-WEANING group and the WEANING group (P = 1.0). Therefore, the AMIR of heifers may be more negatively affected by immunophenotyping at weaning than the AMIR of steers. For steers, CMIR was greater in the POST-WEANING group than the WEANING group (P < 0.001). For heifers, CMIR was not different between the POST-WEANING group and the WEANING group (P = 0.22). The CMIR of steers may be more negatively affected by immunophenotyping at weaning than the CMIR of heifers. Calf age was not associated with AMIR or CMIR for calves phenotyped at weaning or post-weaning. The effect of sire nested within dam age was significant for CMIR for calves in the POST-WEANING group (P < 0.01), but not for calves in the WEANING group (P = 0.67). The results suggest that measuring immunocompetence at weaning may not be representative of a calf's genetic ability to mount an effective immune response, and immunophenotyping should be performed outside the weaning period.

Development of human-directed behavior in dairy calves reared individually or in pairs.

Although social contact between dairy calves has broad effects on their behavioral development, influences of calf social housing on human-animal relationships are less well understood, despite implications for longer-term calf management and welfare. We characterized human-animal interactions in 3 distinct testing contexts to examine effects of social housing on development of human-directed behavior. At birth, Holstein heifer calves were randomly assigned to individual housing (n = 17 calves) or pair housing (n = 17 calves; 1 focal calf/pair). A human approach test was performed twice in the home pen (wk 3 and 5 of life), within an open testing arena (13 × 7 m; wk 4 of life), and within group-housing pens 6 d after all calves were weaned, mingled between treatments, and moved to groups (4 calves/pen; wk 8 of life). For these tests, a human approached, and then extended their hand, over a 2 min period for home and group pen tests and a 5 min period for the arena test, and behavior was recorded from video. During preweaning human approach tests in the home pen, individually housed calves had shorter latencies to contact the human (22.4 vs. 45.1 s; individual vs. pair housing) and spent more time in contact with the human [80.5 vs. 41.1 s; standard error (SE) = 9.9; individual vs. pair housing], with similar responses between repeated tests. In the arena approach test, individually housed calves spent more time oriented toward the human (134.6 vs. 81.3 s; SE = 16.5; individual vs. pair housing), whereas pair-housed calves were more likely to perform pen-directed non-nutritive oral behavior (60 vs. 40% of calves; pair vs. individual housing), suggesting differences in interest directed toward the human compared with the novel environment. We also found that total duration of human contact was correlated between the first home pen approach test and the novel arena test, but that specific response to human approach varied between testing contexts. Effects of treatment persisted during the postweaning group pen approach test, with previously individually housed calves tending to spend more time looking toward the human (53.0 vs. 30.0 s; SE = 9.4; individual vs. pair housing) and more likely to contact the human (47 vs. 12% of calves; individual vs. pair housing). Overall, these results show persistent effects of early life social housing on human-directed behavior which may have implications for longer-term management.

The Impact of Re-Mating Interval and Genotype on Physiological Response of Rabbits after First Kindling

This is an experiment aimed to study the effect of re-mating interval on rabbit does after first kindling on hormonal (insulin, leptin, and T3) and metabolites (triglycerides, urea, and glucose) levels. DNA damage in ovary cells of rabbit does during the 2nd parity was also studied. Two varieties were used: APRI (synthetic line) and Baladi Black (BB, Egyptian breed). A total number of 120 mature rabbit does (60 does for each breed) were 6 months of age and were used at the beginning of the breeding season. Does of each breed were divided into three equal groups according to reproductive rhythm. The 1st group was postpartum (PP). The 2nd group was 11 days after parturition (P11). The 3rd group was post-weaning (PW). There were significant (P&amp;ge;0.05) differences in plasma leptin concentration during 1st parity. The highest value of plasma leptin concentration was recorded by the PW group at mating. Also, there were significant differences in plasma insulin and T3 hormones concentrations of doe rabbits. The highest value of plasma insulin concentration was recorded by the PW group at mating in 1st parity and the highest value of plasma T3 hormone concentration was recorded for the PS group at mating. While there were insignificant differences during 2nd parity in T3 hormone concentration in rabbits, the differences of plasma glucose and triglyceride concentrations of doe rabbits during 1st parity and 2nd parity were significant. However, the highest significant value of plasma glucose concentration was recorded by the PW group at mating. On the other hand, there were insignificant differences in plasma urea concentration of doe rabbits during 1st parity and 2nd parity. Finally, no significant effects were observed on comet length, head diameter, tail length, or DNA % tail.

Rumen Fermentation, Digestive Enzyme Activity, and Bacteria Composition between Pre-Weaning and Post-Weaning Dairy Calves.

Simple SummaryWeaning is very important for young ruminants. At this stage, calves’ main source of nutrients is transferred from milk into solid feed, such as starter and roughage. At the same time, the rumen function of calves undergoes tremendous changes, such as bacteria, which are the main players in rumen function. Our research found that the rumen bacteria network of post-weaning calves was more complex. The fermentation end products, such as acetate, propionate, and butyrate, were higher in the post-weaning calves than the pre-weaning group. However, digestive enzymes such as protease, carboxymethyl cellulase, cellobiohydrolase, and glucosidase were lower in the post-weaning calves than the pre-weaning calves. These findings provided useful information for reference regarding the feeding management of calves.To better understand the transition of rumen function during the weaning period in dairy calves, sixteen Holstein dairy calves were selected and divided into two groups: pre-weaning (age = 56 ± 7 day, n = 8) and post-weaning (age = 80 ± 6 day, n = 8). The rumen fluid was obtained by an oral gastric tube. The rumen fermentation profile, enzyme activity, bacteria composition, and their inter-relationship were investigated. The results indicated that the post-weaning calves had a higher rumen acetate, propionate, butyrate, and microbial crude protein (MCP) than the pre-weaning calves (p < 0.05). The rumen pH in the post-weaning calves was lower than the pre-weaning calves (p < 0.05). The protease, carboxymethyl cellulase, cellobiohydrolase, and glucosidase in the post-weaning calves had a lower trend than the pre-weaning calves (0.05 < p < 0.1). There was no difference in α and β diversity between the two groups. Linear discriminant analysis showed that the phylum of Fibrobacteres in the post-weaning group was higher than the pre-weaning group. At the genus level, Shuttleworthia, Rikenellaceae, Fibrobacter, and Syntrophococcus could be worked as the unique bacteria in the post-weaning group. The rumen bacteria network node degree in the post-weaning group was higher than the pre-weaning group (16.54 vs. 9.5). The Shuttleworthia genus was highly positively correlated with MCP, propionate, total volatile fatty acid, glucosidase, acetate, and butyrate (r > 0.65, and p < 0.01). Our study provided new information about the rumen enzyme activity and its relationship with bacteria, which help us to better understand the effects of weaning on the rumen function.

Dynamic changes in intestinal microbiota in young forest musk deer during weaning.

Weaning is an important event for all mammals, including young forest musk deer. However, weaning stress may cause intestinal microbiota-related disorders. Therefore, high-throughput 16S rRNA gene sequencing was applied to study the dynamic changes in intestinal microbiota during pre-weaning (10 days before weaning) and post-weaning (10 days after weaning) in 15 young forest musk deer. We saw that intestinal microbiota diversity in the post-weaning period was significantly higher than that in the pre-weaning period. The most dominant bacterial phyla were similar in the two groups (Firmicutes, Bacteroidetes and Verrucomicrobia). Meanwhile, we applied Linear discriminant analysis effect size (LefSe) to identify the most differentially microbial taxa in the pre-weaning and post-weaning groups. In the post-weaning forest musk deer, the relative abundance of Actinobacteria, Spirochaetes, Ruminococcaceae_UCG-005, Treponema and Prevotella was higher than in the pre-weaning group. However, higher relative abundance of the phyla Bacteroidetes was found in the pre-weaning group compared with that in the post-weaning group. In summary, this research provides a theoretical foundation for the dynamics of young forest musk deer intestinal microbiota during the weaning transition, which may benefit in understanding the growth and health of forest musk deer.

MON-029 Exposure to Fine Inhalable Particulate Matter of Air Pollution (pm2) of the City of Sao Paulo Causes Tubular Degeneration and Altered Mitochondrial-Related Gene Expression in Mice Testis

Background: Air pollution in industrial and urban centers is related to negative effects in living organisms, including alterations in male fertility. The fine inhalable particulate matter is the most deleterious fraction of air pollution and consists of a complex mixture of particles sized 2.5 µm or less of aerodynamic diameter (PM2.5). Experimental studies had already showed a deleterious effect of air pollution of Sao Paulo city on fertility in male mice. The hypothesis of its toxicity is based on activation of oxidative stress and inflammatory via as well as DNA adducts, leading to epigenetic alterations. Aim: To evaluate, under different conditions, the effects of the exposure to air pollution of city of Sao Paulo on mice testis. Methods: A group of mice was exposed during gestational period and after birth, from the weaning day until adulthood (prenatal and post-weaning group - PNPWG); another group of mice was exposed to PM2.5 during gestational period only (prenatal group - PNG); a third group of mice was exposed to PM2.5 after birth, from the weaning day until adulthood only (post-weaning group - PWG); and finally, a fourth group of mice was exposed to filtered air during gestational period and from post-weaning day until adulthood (control group - CG). Analyzes were performed on testis from adult animals. Stereological techniques were used to analyze structures of testis and Johnsen's score to evaluate spermatogenesis in a qualitative way. DNA microarray were used to evaluate gene expression. Results: Testis of all the exposed groups showed tubular degeneration characteristics. In comparison with CG, the testis of PNPWG showed higher weight and volume, surface area of the seminiferous tubules, volume of the seminiferous epithelium and epididymis weight. Quality of spermatogenesis in PNPWG was also significantly worse in comparison with CG. PWG had similar results when compared with CG, however the only parameters with significantly difference were the volume of the seminiferous epithelium and the quality of spermatogenesis. Mean volume of the seminiferous epithelium from PNG was significantly lower when compared to CG. Gene expression analysis exhibited differential expression of genes mostly related to mitochondrial tRNA in group-to-group comparison. The mt-Ty (mitochondrially encoded tRNA tyrosine) gene was hiperexpressed in PNPWG in comparison with other groups. Conclusion: We demonstrated for the first time that the exposure to PM2.5 of the city of Sao Paulo causes tubular degeneration with decreased or absent spermatogenesis associated with differential expression of genes related to mitochondrial function in mice testis. In addition, we demonstrated that post-natal exposure seems to be more deleterious for the testicular function.

Reevaluating a Standardized Sedation Weaning Protocol for Pediatric Laryngotracheal Reconstruction for Continuous Quality Improvement

Health care organizations are complex and evolving systems. To date, longitudinal evaluation to ensure the sustainability of quality improvement (QI) initiatives has been missing from the otolaryngology literature. We sought to reassess perioperative management of laryngotracheal reconstruction, which requires adequate sedation. Using principles of continuous QI, the objectives of this study were to (1) describe step-by-step methods to sustain QI efforts and (2) revisit a series of process, outcome, and balance measures for sedation weaning management following implementation of a new electronic health record (EHR). A standardized sedation weaning protocol was previously developed and instituted in February 2013. To address healthcare system-wide changes, a 7-step, Institute for Healthcare Improvement methodology was used to reevaluate a series of measures comparing a previous postweaning group (2013-2014; 13 patients) and current post-EHR group (2016; 11 patients). We conducted a focus group review of these 24 patients. The primary outcome measure was length of sedation weaning. Secondary outcome, process, and balance measures included total length of sedation, absence of standardized wean document, absence of specific recommendations on weaning regimen, length of stay, continued weaning at discharge, discharge location, absence of discharge instructions on weaning regimen or iatrogenic withdrawal syndrome (IWS), discharge within 72 hours of stopping weaning, and readmission. The postweaning and post-EHR groups were similar in age (20.5 months [95% CI, 11.92-29.15] vs 26.5 months [95% CI, 17.68-35.40]), as well as male sex (11 of 13 [85%] vs 10 of 11 [91%]), respectively. In the post-EHR group, the standardized sedation wean document was missing from 9 of 11 (82%) medical records. However, the primary outcome measure, length of sedation weaning, remained stable at 9.45 (95% CI, 7.62-11.29) days in the post-EHR group compared with 9.08 (95% CI, 7.00-11.18) days in the postweaning group. In addition, only 5 of 11 (46%) of discharges in the post-EHR group had specific guidance on weaning since the standardized template was no longer in use. As a result, in the post-EHR group, patients were 15.2 (95% CI, 0.46-242.34) times as likely to lack discharge instructions on weaning or IWS. Quality improvement is meant to be a continuous process in which reevaluation of care practices are regularly performed. System-wide redesign can be achieved using a formal methodological approach. Moving forward, notable QI opportunities for our institution included the development of a flexible sedation weaning template, as well as enhancements to discharge instructions to include IWS diagnosis and treatment.

EFFECT OF RE-MATING INTERVAL AFTER THE FIRST PARTURITION ON THE LITTER PARAMETERS, MILK YIELD AND REPRODUCTION TRAITS OF RABBIT DOES

A total number of 120 nulliparous APRI and Baladi Black does (60 does for each breed) were mated at 5 months of age at the beginning of the breeding season (during September) to study the effect of re-mating interval after the first parturition on the litter parameters, milk yield per day and reproduction traits. All does were randomly divided into three equal groups according to reproductive rhythm: The 1st group: post partum (PP), the 2nd group: 11 days after parturition (P11), and the 3rd group: Post weaning (PW) .The body weight of P11 does were slightly higher than that of PP or PW groups. The re- mating interval groups during second parity had significant (P<0.05) effects on litter traits at weaning. Litter size and Litter weight at weaning age in PW group were higher significantly (P<0.05) than those in PP and P11 groups. Litter weight at 21 days of age in PW and P11 groups were higher significantly (P<0.05) than those in PP group. The PW group had significant higher litter size at weaning than those in PP group. Daily milk yield (DMY) after second parity was affected significantly by re-mating interval groups in the third and fourth week of suckling period. GL in PP group was higher significantly (P<0.05) comparing with P11 or PW groups. The values of litter size and weight traits were better for APRI does comparing with BB except litter weight at 21 days. The difference in results between the two breeds in daily milk yield showed generally higher trend of daily milk yield for APRI over BB. The Kindling interval and the gestation period were significantly (P<0.05) affected by interaction of re-mating interval group and breed. In conclusion, applying a lengthened period after the first kindling (by more than 10 days or after weaning) had a favorable effect on the does’ production.

Effects of overfeeding in breastfeeding period on blood pressure and vascular endothelial dilation function of rats

Objective To study the effects of postnatal overfeeding and high-fat diet on blood pressure of rats, and to explore the pathophysiological mechanism underlying hypertension induced by continuous early postnatal overfeeding. Methods Male Sprague-Dawley rats were randomly divided into normal feeding group (10/litter) and overfeeding group (3/litter) on postnatal day 3 with a random number table. After weaning at postnatal week 3, the rats were randomly given standard chow or high-fat (HF) diet until week 16. Hence four groups were analyzed, namely normal feeding group, breastfed overfeeding group, post-weaning overfeeding group, and continuous overfeeding group. Body weight was continuously monitored in each week. Visceral fat pad(retroperitoneal and perigenital), systolic pressure, and heart rate were observed at week 3 and week 16. Thoracic aorta was sampled for measurement of vascular endothelial dilation function. Histological morphology was observed with HE staining, nitric oxide content of thoracic aorta was detected with nitrate reductase method. The mRNA expression of endothelial nitric oxide synthase (eNOS) in thoracic aorta was determined by real-time polymerase chain reaction. The protein expressions of eNOS and phosphorylated eNOS were determined by Western blot. Results At week 3, breastfed overfeeding rats displayed significantly larger body weight [(77.80±0.57) g vs. (62.80±0.85)g, t=14.576, P<0.01] and visceral fat [retroperitoneal: (8.19±0.49)mg/g vs. (4.92±0.31)mg/g, t=5.629, P<0.01; perigenital: (3.50±0.29)mg/g vs. (2.08±0.13)mg/g, t=4.552, P<0.01] compared with normal feedindg rats, and the protein expression of phosphorylated eNOS in aortic tissues was significantly reduced to week 16 (F=15.215, P<0.01); high-fat diet feeding after weaning further increased the body weight and fat mass in breastfed overfeeding rats. At week 16, continuous overfeeding rats showed hypertension [(149±1.94)mmHg (1 mmHg=0.133 kPa), F=22.834, P<0.01], impaired vascular endothelial dilation function (F=7.648, P<0.05), and reduced protein expression of phosphorylated eNOS(F=15.215, P<0.01), while the post-weaning overfeeding group only had elevated blood pressure. Conclusions Overfeeding in breastfeeding period and high-fat diet after weaning leads to hypertension. The continuous decrease in phosphorylated eNOS in vascular tissues may be an important molecular process participating in the occurrence of vascular endothelial dysfunction in adults induced by postnatal overfeeding. Key words: Early postnatal overfeeding; Vascular endothelial dilation function; Hypertension; Nitric oxide; Phosphorylated endothelial nitric oxide synthase

Mycoplasma hyopneumoniae infections in peri-weaned and post-weaned pigs in Belgium and The Netherlands: Prevalence and associations with climatic conditions

Mycoplasma hyopneumoniae (M. hyo) is an important pathogen in modern intensive pig farming in Europe. The objectives of the present study were (1) to use the tracheobronchial swab (TBS) technique to obtain data on the distribution of M. hyo infections in recently weaned pigs in Belgium and The Netherlands, and (2) to look for associations between infection prevalence and specific climatic conditions. One hundred and seventy-six pig herds were randomly selected and 30 piglets sampled on each farm: 18 at 3–5 weeks of age and 12 at 6–11 weeks. Mucus collected from the tracheobronchial bifurcation and suspended in saline was subjected to PCR analysis for M. hyo.In 27% of herds (n = 44) at least one piglet tested positive for M. hyo at 3–5 weeks of age, and 29% (n = 47) at 6–11 weeks of age. The individual animal prevalence at the two ages was 7.1% and 10.9%, respectively. The probability of 3–5 week old piglets being M. hyo-positive was negatively associated with the precipitation rate (odds ratio [OR] = 0.971) during the week preceding the sampling. In the older post-weaning group, the odds of being M. hyo-positive at piglet level were significantly affected by season (OR of detection during autumn compared to summer 20.9). Thus, under Belgian and Dutch field conditions, piglets may be infected with M. hyo very early in life, with prevalence increasing further during the post-weaning period.

Intestinal microbiota diversity and expression of pattern recognition receptors in newly weaned piglets

This study evaluated the gastrointestinal microbial diversity and the expression of pattern recognition receptors (PRRs) of the small intestine during the first week post-weaning in newly weaned piglets. Sixteen piglets were sacrificed on days 0, 1, 4, and 7 post-weaning. Luminal contents from the stomach, ileum, and colon were collected to determine the microbiota diversity; intestinal mucosa from the ileum was collected to assess mRNA expression of PRRs, including toll-like receptors (TLRs) and NOD-like receptors (NLRs); sections of ileum were examined immunohistochemically to assess the immunoglobulin-secreting cells. The results showed that the number of denaturing gradient gel electrophoresis (DGGE) bands from the ileum and colon contents were significantly reduced in the d 4 post-weaning group. Biodiversity indexes (Shannon–Wiener index, richness index, and evenness index) were significantly decreased in the ileum of weaning groups. These indexes decreased in the colon of the d 4 post-weaning group. No significant differences were obtained in the stomach. With the exception of TLR5, the mRNA expressions of TLR2, TLR4, and TLR7 increased post-weaning. The mRNA expressions of NOD1 and NOD2 were significantly affected in the d 4 post-weaning group, and there were no significant differences in the d 1 or d 7 post-weaning groups. Analysis of the immunoglobulin-secreting (IgA, IgG, and IgM) cells showed that the ratio of each immunoglobulin was significantly higher on d 7 than d 0. The results revealed that microbial diversity was lower in the ileum and on d 4 post-weaning. Weaning significantly affected the expression of intestinal PRRs mainly on d 1 and d 4 post-weaning. The expression of specific PRRs was triggered by weaning to recognize distinctive microbiota and promote the development and maturation of the intestinal mucosal immunity.

Alpha (1,2)-Fucosyltransferase M307A Polymorphism Improves Piglet Survival

To confirm the beneficial effects of alpha (1,2)-fucosyltransferase (FUT1) M307 A on piglet survival on commercial farms, we performed PCR-RFLP analysis of FUT1 M307 in successfully marketed (n = 245) and disease affected/deceased pigs during weaning (n = 252) at a commercial farm. We also evaluated the FUT1 genotypes of 190 healthy pigs from three different genetic backgrounds. The distribution of genotypes differed between the successfully marketed and disease affected/deceased pig groups. The frequency of the A allele, associated with resistance to edema and post-weaning diarrhea, was higher in the post-weaning survival group (0.21) than in the non-survival group (0.16, P < 0.05). The odds ratio for piglet survival between AA and GG genotypes was 1.98; thus, piglet survival for individuals with the AA genotype was almost two-fold greater than for GG individuals. The FUT1 gene polymorphism can be used as an effective marker for selection programs to improve post-weaning piglet survival.

Effect of Gonadotropins during Hot Summer Season Given at Different Times after Weaning on Selected Reproductive Indicators of the Sow

The experiment was performed on a large indoor herd during a hot season period in Alföld, Hungary. The post-weaning sows (F1 and F2 of Large White × Landrace mated to Duroc boars (mean parity 3.4 +/-0.7 SD; mean body condition 3.01 +/-0.3 SD, previous lactation length of 28.3 +/-1.5 d) were divided into four groups of similar body condition, lactation length and parity and were treated as follows: Group 1: sows (n = 420) were injected subcutaneously with 400 I.U. of Gonadotropinum sericum (pregnant mare serum gonadotropin, PMSG [eCG]) and 200 I.U. of Gonadotropinum chorionicum (human choriongonadotropin, HCG [hCG]) one day after weaning. Group 2: sows (n = 405) received subcutaneously 4 ml of saline injection one day after weaning. Group 3: sows (n = 425), purposely chosen from among animals that did not show heat within 7 days after weaning, were treated on day 7 post-weaning with PMSG and HCG as the animals in group 1. Group 4: sows (n = 415) purposely chosen from among animals that did not show heat within 7 days after weaning, were treated on day 7 post-weaning as group 2. Sows expressing oestrus, sows ovulating after treatment, treatment to oestrus intervals and follicular sizes were evaluated. The number of sows expressing oestrus, sows ovulating, and treatment to oestrus intervals differed between the groups (group 1 vs. 2: P &lt; 0.05, group 3 vs. 4: P &lt; 0.01). The sows treated with PMSG and HCG on day 7 post-weaning (group 3) had smaller (P &lt; 0.05) follicular diameters compared to the sows that were treated one day after weaning. Group 4 sows had a smaller follicular diameter (3.6 +/- 0.6 mm) compared to group 1 (P &lt; 0.001) and 3 (P &lt; 0.01). The present results show that the gonadotropin treatment one day after weaning or in the case of anoestrus 7 days after weaning overrides the negative effects of the hot summer season and effectively prevents seasonal infertility of the breeding sow.

Specific timing of taurine supplementation affects learning ability in mice

The effects of taurine supplementation on visual discrimination in mice were examined. Taurine, 2-aminoethane-sulphonic acid, found in high concentrations in the central nervous system of mammals and in human milk, has been shown to be essential for development. Male mice were divided into four groups according to taurine supplementation periods. 1) Lifelong: taurine (400 mg/kg/day) was dissolved in distilled water and provided as drinking water. In the prenatal period, taurine was given via the mother. After weaning mice were administered taurine in drinking water. 2) Pre-weaning: mice were exposed to taurine prior to weaning, 3) Post-weaning: mice were exposed to taurine after weaning. 4) Control: no supplementation of taurine. It was shown that the Lifelong group required a longer period of time to acquire visual discrimination than the Control group. Conversely, in the Post-weaning group, mice learned the task faster than Controls. Visual discrimination learning time in the Pre-weaning group showed no significant difference compared with that in the Control group. From these results, we suggest that the perinatal to early postnatal period is a “sensitive period” where taurine supplementation can result in retardation of learning in later life. At the same time, taurine supplementation after weaning improved visual discrimination learning. Thus, timing of taurine supplementation affected learning.

Glial fibrillary acidic protein and RNA expression in adult rat hippocampus following low-level lead exposure during development.

The astroglial cytoskeletal element, glial fibrillary acidic protein (GFAP), is a generally accepted sensitive indicator for neurotoxic effects in the mature brain. We used GFAP as a marker for structural changes in rat hippocampus related to chronic low level lead exposure during different developmental periods. Four groups of rats were investigated: a control group, a perinatal group, which was exposed during brain development (E0-P16), a permanent group, exposed during and after brain development (E0-P100), and a postweaning group, exposed after brain development (P16-P100). Sections were processed for light microscopy (hematoxylin-eosin, Nissl, periodic acid Schiff (PAS) and GFAP-specific immunohistology), for electron microscopy, and for in-situ hybridization (GFAP). Sections were prepared from animals tested for active avoidance learning (AAL) and long-term potentiation (LTP). Chronic lead exposure did not affect glial and neuronal functions, as assessed by LTP and AAL, when lead exposure started after brain development (postweaning group). In this group, astrocytes displayed increased GFAP and GFAP gene transcript levels. However, lead exposure affected neuronal and glial function when the intoxication fell into the developmental period of the brain (perinatal and permanent groups). In these groups, LTP and AAL were impaired, and astrocytes failed to react to the toxic exposure with an adequate increase of GFAP and GFAP gene transcripts. Although GFAP is an accepted marker for neurotoxicity, our data suggest the marker function of GFAP to be restricted to postnatal toxic insult.

Phenobarbitone: adverse effects on reproductive performance and offspring development in the Mongolian gerbil, (Meriones unguiculatus)

Phenobarbitone at a concentration of 500 mg/l in drinking fluid of gerbils during pregnancy (60 mg/kg) and lactation (136 mg/kg) markedly reduced the proportion of animals bearing litters, decreased pup weights at birth and during later life and delayed development of the self-righting reflex, auditory startle reaction, eye opening and full fur coverage. It also prolonged the period of suckling. Scars of implantation were evident in uterine horns of 60% of treated and in none of control females that had failed to give birth. Treated offspring after weaning were given phenobarbitone (500 mg/l; 42-124 mg/kg) as their drinking fluid throughout life and a further group of gerbils received this concentration of the drug from the time of weaning. Seizure susceptibility was unaltered by the drug treatment, and the only evidence of behavioural change was seen in offspring gerbils at 6 weeks when the bout length of social investigation during encounters was increased. Drug-treated offspring showed no abnormality in brain weight relative to body weight. Weight gain and brain weight remained normal among the gerbils given phenobarbitone after weaning. The drug treatment reduced scent gland size in breeding males, though not in the offspring, and had no effect on weights of the testes or ovaries and uterus. no effect on weights of the testes or ovaries and uterus. Plasma concentrations of phenobarbitone in females of the postweaning group amounted on average to 4.4 mg/kg. Most of the adverse effects of this dose of phenobarbitone in the gerbil can thus be seen to be associated either with reproductive impairment or with exposure during sensitive periods of early development.

近交系マウスの飼育条件の差異が母親行動とその仔の成熟後のopen-field行動に及ぼす効果

The mother-infant interaction was studied in the mouse by changing the size of litters. Litter size was reduced to either two or eight on the day following parturition, and the behavior of the mothers was observed by the time-sampling technique during the entire lactation period. There was no significant difference in their maternal behavior, (nursing, licking pups, and nest bulding). The mothers of the small litters were less active and spent more time resting than the mothers of the large litters. The offspring were re-grouped at weaning (21 days of age) into groups of two or eight of the same sex, and tested in an open field at nine weeks of age. The pre-weaning litter size and the post-weaning group size affected different aspects of the open-fieldbehavior.

Caught Between Ethics and Economics: Pharmacists and Tobacco

This study evaluated the gastrointestinal microbial diversity and the expression of pattern recognition receptors (PRRs) of the small intestine during the first week post-weaning in newly weaned piglets. Sixteen piglets were sacrificed on days 0, 1, 4, and 7 post-weaning. Luminal contents from the stomach, ileum, and colon were collected to determine the microbiota diversity; intestinal mucosa from the ileum was collected to assess mRNA expression of PRRs, including toll-like receptors (TLRs) and NOD-like receptors (NLRs); sections of ileum were examined immunohistochemically to assess the immunoglobulin-secreting cells. The results showed that the number of denaturing gradient gel electrophoresis (DGGE) bands from the ileum and colon contents were significantly reduced in the d 4 post-weaning group. Biodiversity indexes (Shannon–Wiener index, richness index, and evenness index) were significantly decreased in the ileum of weaning groups. These indexes decreased in the colon of the d 4 post-weaning group. No significant differences were obtained in the stomach. With the exception of TLR5, the mRNA expressions of TLR2, TLR4, and TLR7 increased post-weaning. The mRNA expressions of NOD1 and NOD2 were significantly affected in the d 4 post-weaning group, and there were no significant differences in the d 1 or d 7 post-weaning groups. Analysis of the immunoglobulin-secreting (IgA, IgG, and IgM) cells showed that the ratio of each immunoglobulin was significantly higher on d 7 than d 0. The results revealed that microbial diversity was lower in the ileum and on d 4 post-weaning. Weaning significantly affected the expression of intestinal PRRs mainly on d 1 and d 4 post-weaning. The expression of specific PRRs was triggered by weaning to recognize distinctive microbiota and promote the development and maturation of the intestinal mucosal immunity.

‘The Motion before the House ...’

This study evaluated the gastrointestinal microbial diversity and the expression of pattern recognition receptors (PRRs) of the small intestine during the first week post-weaning in newly weaned piglets. Sixteen piglets were sacrificed on days 0, 1, 4, and 7 post-weaning. Luminal contents from the stomach, ileum, and colon were collected to determine the microbiota diversity; intestinal mucosa from the ileum was collected to assess mRNA expression of PRRs, including toll-like receptors (TLRs) and NOD-like receptors (NLRs); sections of ileum were examined immunohistochemically to assess the immunoglobulin-secreting cells. The results showed that the number of denaturing gradient gel electrophoresis (DGGE) bands from the ileum and colon contents were significantly reduced in the d 4 post-weaning group. Biodiversity indexes (Shannon–Wiener index, richness index, and evenness index) were significantly decreased in the ileum of weaning groups. These indexes decreased in the colon of the d 4 post-weaning group. No significant differences were obtained in the stomach. With the exception of TLR5, the mRNA expressions of TLR2, TLR4, and TLR7 increased post-weaning. The mRNA expressions of NOD1 and NOD2 were significantly affected in the d 4 post-weaning group, and there were no significant differences in the d 1 or d 7 post-weaning groups. Analysis of the immunoglobulin-secreting (IgA, IgG, and IgM) cells showed that the ratio of each immunoglobulin was significantly higher on d 7 than d 0. The results revealed that microbial diversity was lower in the ileum and on d 4 post-weaning. Weaning significantly affected the expression of intestinal PRRs mainly on d 1 and d 4 post-weaning. The expression of specific PRRs was triggered by weaning to recognize distinctive microbiota and promote the development and maturation of the intestinal mucosal immunity.