Methodological challenges in the study of fetal growth

Several conceptual and methodological challenges must be solved in order to create knowledge that can be useful to pregnant women, their families, and any clinicians who serve them: (1) going beyond nominal and ordinal hypotheses and presenting estimates of conditional probabilities; (2) focusing on clearly defined outcomes; (3) modeling the relationship of fetal growth and length of gestation; (4) understanding the process of fetal growth even though most of our data is cross-sectional; (5) estimating the independent effects of genetics, race, ethnicity, maternal risk behaviors, medical prenatal care, and socioeconomic status on fetal growth and length of gestation; and (6) estimating the independent effects of maternal pre-pregnancy weight, weight gain during pregnancy, and nutrition on fetal growth and length of gestation. The analysis and writing of this study was funded, in part, by a grant from the National Institute of Child Health and Human Development (NICHD RO1 HD 20511). Troy D. Abell, Ph.D., M.P.H., is associate professor of anthropology and adjunct associate professor of family medicine at the University of Oklahoma. His major interests are in the biocultural determinants of fetal growth and the epistemologic issues inherent in statistical reasoning, scientific inference, and decision analysis.     

Depression in pregnancy,infant birth weight and DNA methylation of imprint regulatory elements

Depressed mood in pregnancy has been linked to low birth weight (LBW, < 2,500 g), a risk factor for adult-onset chronic diseases in offspring. We examined maternal depressed mood in relation to birth weight and evaluated the role of DNA methylation at regulatory sequences of imprinted genes in this association. We measured depressed mood among 922 pregnant women using the CES-D scale and obtained birth weight data from hospital records. Using bisulfite pyrosequencing of cord blood DNA from 508 infants, we measured methylation at differentially methylated regions (DMRs) regulating imprinted genes IGF2/H19, DLK1/MEG3, MEST, PEG3, PEG10/SGCE, NNAT and PLAGL1. Multiple regression models were used to examine the relationship between depressed mood, birth weight and DMR methylation levels. Depressed mood was associated with a more that 3-fold higher risk of LBW, after adjusting for delivery mode, parity, education, cigarette smoking, folic acid use and preterm birth. The association may be more pronounced in offspring of black women and female infants. Compared with infants of women without depressed mood, infants born to women with severe depressed mood had a 2.4% higher methylation at the MEG3 DMR. Whereas LBW infants had 1.6% lower methylation at the IGF2 DMR, high birth weight (> 4,500 g) infants had 5.9% higher methylation at the PLAGL1 DMR compared with normal birth weight infants. Our findings confirm that severe maternal depressed mood in pregnancy is associated with LBW, and that MEG3 and IGF2 plasticity may play important roles.     

Depression in pregnancy,infant birth weight and DNA methylation of imprint regulatory elements

Depressed mood in pregnancy has been linked to low birth weight (LBW, < 2,500 g), a risk factor for adult-onset chronic diseases in offspring. We examined maternal depressed mood in relation to birth weight and evaluated the role of DNA methylation at regulatory sequences of imprinted genes in this association. We measured depressed mood among 922 pregnant women using the CES-D scale and obtained birth weight data from hospital records. Using bisulfite pyrosequencing of cord blood DNA from 508 infants, we measured methylation at differentially methylated regions (DMRs) regulating imprinted genes IGF2/H19, DLK1/MEG3, MEST, PEG3, PEG10/SGCE, NNAT and PLAGL1. Multiple regression models were used to examine the relationship between depressed mood, birth weight and DMR methylation levels. Depressed mood was associated with a more that 3-fold higher risk of LBW, after adjusting for delivery mode, parity, education, cigarette smoking, folic acid use and preterm birth. The association may be more pronounced in offspring of black women and female infants. Compared with infants of women without depressed mood, infants born to women with severe depressed mood had a 2.4% higher methylation at the MEG3 DMR. Whereas LBW infants had 1.6% lower methylation at the IGF2 DMR, high birth weight (> 4,500 g) infants had 5.9% higher methylation at the PLAGL1 DMR compared with normal birth weight infants. Our findings confirm that severe maternal depressed mood in pregnancy is associated with LBW, and that MEG3 and IGF2 plasticity may play important roles.     

The COVID-19 pandemic and birth outcomes in 2020: The role of prenatal care and other channels

We use national birth data to assess the associations between the COVID-19 pandemic during 2020 and birth outcomes in Uruguay. Employing interrupted time series difference-in-differences techniques, we find mixed results, with some pregnancies showing increases in the likelihood of very preterm or very-low-weight births, and some others showing decreases in the incidence of moderate prematurity and moderate low birth weight. Adverse outcomes are more likely among women with low education, women with previous children, and with risk factors, such as smoking or being older than 34. We observe improvements in health at birth for children of non-smokers, women younger than 35, and women with no other children. We underscore the role of health care by showing that women in the private sector, who suffered the strongest contraction in face-to-face prenatal care use, experienced more adverse birth outcomes. Our results also suggest that the economic recession and an increased burden of childcare were behind the increases in preterm and very-low-weight births. Because pollution is an unlikely channel for the positive results, we hypothesize that for some pregnancies, the pandemic improved the intrauterine habitat by leading to a quieter and healthier lifestyle.     

Hypothalamus integrity and appetite regulation in low birth weight rats reared artificially on a high-protein milk formula

High-protein (HP) milk formulas are routinely used in infants born with a low birth weight (LBW) to enhance growth and ensure a better verbal IQ development. Indirect evidence points to a link between an HP intake during early life and the prevalence of obesity in later life. We hypothesized that HP milk supplementation to LBW pups during early postnatal life would impact hypothalamic appetite neuronal pathways development with consequences, at adulthood, on energy homeostasis regulation. Rat pups born with a LBW were equipped with gastrostomy tubes on the fifth day of life. They received a milk formula with either normal protein (NP, 8.7 g protein/dl) or high protein content (HP; 13.0 g protein/dl) and were subsequently weaned to a standard, solid diet at postnatal day 21. Rats that had been fed HP content milk gained more weight at adulthood associated with an increase of plasma insulin, leptin and triglycerides concentrations compared to NP rats. Screening performed on hypothalamus in development from the two groups of rats identified higher gene expression for cell proliferation and neurotrophin markers in HP rats. Despite these molecular differences, appetite neuronal projections emanating from the arcuate nucleus did not differ between the groups. Concerning feeding behavior at adulthood, rats that had been fed HP or NP milk exhibited differences in the satiety period, resting postprandial duration and nocturnal meal pattern. The consequences of HP milk supplementation after LBW will be discussed in regard to neural development and metabolic anomalies.     

低出生体重儿肠道微生态构建影响因素的动态监测

目的 动态监测低出生体重儿肠道菌群,分析不同体重、不同喂养方式及疾病状态等因素对患儿肠道微生态的影响,为规范临床低出生体重儿宫外营养支持措施及治疗手段提供依据。方法 应用16S rRNA荧光定量PCR技术检测正常新生儿和低出生体重儿生后第1、3、7天粪便中大肠埃希菌、肠球菌、乳杆菌及双歧杆菌的含量。结果 （1）在生后7 d内,无论正常新生儿还是低出生体重儿,其粪便中大肠埃希菌、肠球菌、乳杆菌和双歧杆菌的含量均随日龄的增加而增加,且生后7 d内正常新生儿的粪便中大肠埃希菌、肠球菌、乳杆菌和双歧杆菌的含量均显著高于低出生体重儿（P<0.05）,正常新生儿生后7 d内粪便中各细菌的增长率均高于低出生体重儿。（2）体重2 000~2 500 g的低出生体重儿粪便中大肠埃希菌和肠球菌在各日龄中的含量明显高于体重<2 000 g的新生儿（P<0.05）;同时其粪便中双歧杆菌和乳杆菌含量在3日龄和7日龄阶段明显高于体重<2 000 g的新生儿（P<0.05）。（3）3日龄和7日龄母乳喂养组的低出生体重儿粪便中双歧杆菌和乳杆菌含量明显高于乳制品喂养组（P<0.05）;且母乳喂养组新生儿生后7日内粪便中大肠埃希菌、乳杆菌和双歧杆菌含量的增长率均高于乳制品喂养组,尤其是双歧杆菌的增长率（126.49% vs 54.81%）。（4）合并并发症的3日龄和7日龄的低出生体重儿,粪便中乳杆菌和双歧杆菌含量均明显低于无合并症的低出生体重儿（P<0.05）;且无并发症组的低出生体重儿其粪便中肠球菌、乳杆菌和双歧杆菌的增长率均高于有并发症组的低出生体重儿,大肠埃希菌增长率则低于有并发症组。结论 低出生体重儿肠道菌群的定植时间晚且数量少,体重、喂养方式及有无并发症是影响新生儿肠道菌群丰度的重要因素。母乳喂养可促进低出生体重儿肠道中益生菌的定植。疾病因素会导致肠道菌群丰度的降低,使肠道菌群紊乱,其程度可能与病情的严重程度相关。     

低出生体重儿肠道菌群及肠道屏障功能的研究

目的 研究低出生体重儿的肠道菌群分布情况和肠道屏障功能的变化。方法 以低出生体重儿（1 500 g≤体重＜2 500 g）为研究对象,采用16S rRNA荧光定量PCR技术和JY-DLT肠道屏障功能分析系统检测低出生体重儿出生后第7天粪便中双歧杆菌、乳杆菌、大肠埃希菌、肠球菌4种细菌的含量以及血清中的二胺氧化酶、D-乳酸和细菌内毒素的浓度,比较正常新生儿与低出生体重儿肠道菌群和肠道屏障功能的差异,分析不同喂养方式、并发症对低出生体重儿肠道菌群及肠道屏障功能的影响。结果 （1）低出生体重儿组粪便中大肠埃希菌、肠球菌、乳杆菌、双歧杆菌含量均明显低于健康新生儿组（P＜0.05）,血清中二胺氧化酶、D-乳酸高于健康新生儿组（P＜0.05）,细菌内毒素水平差异无统计学意义（P＞0.05）。（2）母乳喂养组低出生体重儿粪便中双歧杆菌和乳杆菌含量明显高于乳制品喂养组（P<0.05）,且血清中二胺氧化酶和和D-乳酸含量低于乳制品喂养组（P<0.05）,细菌内毒素水平差异无统计学意义（P＞0.05）。（3）无并发症组低出生体重儿粪便中乳杆菌和双歧杆菌含量明显高于有并发症组（P＜0.05）,其血清中二胺氧化酶、D-乳酸和细菌内毒素水平均低于有并发症的低出生体重儿（P＜0.05）。结论 低出生体重儿的肠道菌群和肠道屏障功能都与正常新生儿存在差异,母乳喂养有助于肠道有益菌的定植和肠道屏障功能的恢复。     

Newborn Brain: Body weight ratios.

Newborn brain:body weight ratios are generally considered to be constant in man. In autopsy studies many factors influence the measured weight of the brain, and therefore the conclusions based on such observations, including the gestational age of the material, the presence or absence of intrauterine growth retardation, and the cause of death. In this study these influences have been eliminated by careful selection of normally grown fullterm newborns not subject to the factors influencing brain weight. Using double logarithmic plots, brain size in fullterm newborns is found to be related to the 0.64 power of birth weight. There is a negative correlation between relative brain size and increasing fullterm birth size in man.     

Prenatal care demand and its effects on birth outcomes by birth defect status in Argentina

Our objective was to identify determinants of prenatal care demand and evaluate the effects of this demand on low birth weight and preterm birth. Delay in initiating prenatal care was modeled as a function of pregnancy risk indicators, enabling factors, and regional characteristics. Conditional maximum likelihood (CML) estimation was used to model self-selection into prenatal care use when estimating its effectiveness. Birth registry data was collected post delivery on infants with and without common birth defects born in 1995-2002 in Argentina using a standard procedure. Several maternal health and fertility indicators had significant effects on prenatal care use. In the group without birth defects, prenatal care delay increased significantly LBW and preterm birth when accounting for self-selection using the CML model but not in the standard probit model. Prenatal care was found to be ineffective on average in the birth defect group. The self-selection of higher risk women into earlier initiation of prenatal care resulted in underestimation of prenatal care effectiveness when using a standard probit model with several covariates. Large improvements in birth outcomes are suggested with earlier initiation of prenatal care for pregnancies uncomplicated with birth defects in Argentina, implying large opportunity costs from the long waiting time observed in this sample (about 17 weeks on average). The suggested ineffectiveness for pregnancies complicated with common birth defects deserves further research.     

早期应用微生态制剂对极低出生体重儿影响的临床观察

目的观察早期应用微生态制剂对极低出生体重儿黄疸、喂养、生长以及免疫功能的影响。方法我院NICU收治的生后24h内极低出生体重儿84例,随机分为观察组46例,对照组38例。观察组生后4h内开始口服或鼻饲胃管服用妈咪爱0.5g,2次/d,连用14d。观察两组达到高胆红素血症标准的人数,以及生后24h、5d总胆红素值;喂养不耐受人数;生后5d生理性体重下降及1个月体重增长情况;生后1个月免疫学指标。并加以对比。结果24h内血清胆红素比较无统计学意义(P0.05),治疗5d后观察组血清总胆红素明显低于对照组(P0.05),观察组出现高胆红素血症人数明显低于对照组(P0.05);观察组喂养不耐受出现例数明显低于对照组(P0.01);观察组生后5d体重下降的克数低于对照组(P0.05),1个月时体重增长克数高于对照组(P0.01);观察组IgA水平较对照组明显增加(P0.05),但IgG及IgM含量与对照组比较差异无统计学意义(P0.05)。结论早期应用微生态制剂能降低血清胆红素水平,对预防极低出生体重儿高胆红素血症有一定作用;能提高喂养的耐受性,有利于患儿生长发育;对极低出生体重儿的肠道功能及免疫功能有明显影响,能增加免疫球蛋白IgA水平,从而促进体液免疫的发展。     

极低出生体重婴幼儿发生宫外生长迟缓的危险性分析

目的:比较不同出生体重婴幼儿的生长特点,并分析影响极低出生体重婴幼儿发生宫外生长迟缓的危险因素。方法:回顾性调查2012年至2015年我院婴幼儿的临床资料,并按出生体重分成极低出生体重组和对照组,比较不同组别婴幼儿的差异性并采用logistics回归分析极低出生体重婴幼儿发生宫外生长迟缓的危险因素。结果:本次研究共收集婴幼儿200例,其中极低出生体重组118例,对照组82例,两组婴幼儿在胎龄、是否存在FGR或EUGR、首次接受肠内营养的时间、住院天数和出院时体重增长量上存在统计学差异,表现为极低出生体重组的婴幼儿的胎龄要小于对照组婴幼儿,且住院天数、首次接受肠内营养的时间和出院时体重增长量都要明显高于对照组婴幼儿,但对照组发生宫外生长迟缓和宫内生长受限的比例却明显低于极低出生体重组(P0.05)。针对极低出生体重婴幼儿的logistics回归分析显示,极低出生体重婴幼儿出生时伴有宫内生长受限或胎龄越小,则越有可能发生宫外生长迟缓(P0.05)。结论:极低出生体重的婴幼儿发生宫外生长迟缓的比例要明显高于低出生体重婴幼儿,其中婴幼儿本身的宫内生长受限和胎龄是影响极低出生体重婴幼儿发生宫外生长迟缓的最主要危险因素。     

益生菌制剂治疗极低出生体重儿喂养不耐受的临床研究

目的探讨益生菌制剂对极低出生体重儿（very low birth weight infant,VLBW）喂养不耐受的影响。方法将56例极低出生体重儿随机分成治疗组和对照组,每组28例。2组均予静脉营养及早产儿配方奶喂哺,治疗组在早产儿配方奶喂哺时添加益生菌制剂,每次0．5g,3次／d,2组同时记录恢复出生体重时间、达全胃肠喂养时间及黄疽消退时间。结果治疗组恢复出生体重时间、达全胃肠喂养时间均显著短于对照组（P〈0．01）,治疗组黄疸消退时间也明显缩短（P〈0．05）。微生态制剂治疗过程中无不良反应发生。结论益生菌制剂可改善极低出生体重儿喂养不耐受,促进患儿体重增长,缩短达到全胃肠喂养时间,值得推广应用。     

Effect of average litter weight in pigs on growth performance,carcass characteristics and meat quality of the offspring as depending on birth weight

Offspring born from normal litter size (10 to 15 piglets) but classified as having lower than average birth weight (average of the sow herd used: 1.46 ± 0.2 kg; mean ± s.d.) carry at birth negative phenotypic traits normally associated with intrauterine growth restriction, such as brain-sparing and impaired myofiber hyperplasia. The objective of the study was to assess long-term effects of intrauterine crowding by comparing postnatal performance, carcass characteristics and pork quality of offspring born from litters with higher (>1.7 kg) or lower (<1.3 kg) than average litter birth weight. From a population of multiparous Swiss Large White sows (parity 2 to 6), 16 litters with high (H = 1.75 kg) or low (L = 1.26 kg) average litter birth weight were selected. At farrowing, two female pigs and two castrated pigs were chosen from each litter: from the H-litters those with the intermediate (H_I = 1.79 kg) and lowest (H_L = 1.40 kg) birth weight, and from L-litters those with the highest (L_H = 1.49 kg) and intermediate (L_I = 1.26 kg) birth weight. Average birth weight of the selected H_I and L_I piglets differed (P < 0.05), whereas birth weight of the H_L- and L_H-piglets were similar (P > 0.05). These pigs were fattened in group pen and slaughtered at 165 days of age. Pre-weaning performance of the litters and growth performance, carcass and meat quality traits of the selected pigs were assessed. Number of stillborn and pig mortality were greater (P < 0.05) in L- than in H-litters. Consequently, fewer (P < 0.05) piglets were weaned and average litter weaning weight decreased by 38% (P < 0.05). The selected pigs of the L-litters displayed catch-up growth during the starter and grower–finisher periods, leading to similar (P > 0.05) slaughter weight at 165 days of age. However, H_L-gilts were more feed efficient and had leaner carcasses than H_I-, L_H- and L_I-pigs (birth weight class × gender interaction P < 0.05). Meat quality traits were mostly similar between groups. The marked between-litter birth weight variation observed in normal size litters had therefore no evident negative impact on growth potential and quality of pigs from the lower birth weight group.     

Compensatory growth feeding strategy does not overcome negative effects on growth and carcass composition of low birth weight pigs

The aim of this study was to evaluate whether the compensatory growth feeding strategy could be a suitable solution for overcoming the negative effects on growth, carcass composition and meat quality of low birth weight pigs. Forty-two Swiss Large White barrows from 21 litters were selected at weaning and categorized into either being light (L; >0.8 and <1.3 kg) or heavy (H; >1.7 kg) birth weight pigs. From 27.8 kg BW, pigs were assigned within birth weight group to one of three feeding groups: AA: ad libitum access to the grower and finisher diet, RR: restricted access to the grower and finisher diet or RA: restricted access to the grower diet and ad libitum access to the finisher diet. At slaughter, the longissimus (LM) and semitendinosus (STM) muscles were removed from the right side of the carcass. Weight, girth and length of the STM and the LM area were determined after muscle excision. Carcass characteristics and meat quality traits were assessed. Using mATPase histochemistry, myofibre size and myofibre type distribution were determined in the LM and STM. Because of longer days on feed, total feed intake was greater (P<0.01) and feed efficiency was lower (P<0.01) in L than H barrows. Regardless of the birth weight group, AA and RA barrows grew faster (P<0.05) than RR barrows. During the compensatory growth period, RA barrows grew faster (P<0.05) than AA or RR barrows. Growth efficiency did not differ between RA and RR barrows but was greater (P<0.05) compared with AA barrows. Carcasses of L barrows were fatter as indicated by the lower (P⩽≤0.05) lean meat and greater (P⩽0.02) omental and subcutaneous fat percentage. Lean meat percentage was lower (P⩽0.05) in AA and RA than RR barrows. These differences caused by ad libitum feed access tended to be greater (feeding regime × birth weight group interaction; P<0.08) in L than H barrows. In L barrows, slow oxidative, fast oxidative glycolytic and overall average myofibre size of the LM and the fast glycolytic myofibres and overall average myofibre size of the dark portion of the STM were larger (P⩽0.03) than in H barrows. The study revealed that the compensatory growth feeding strategy was inadequate in overcoming the disadvantages of low birth weight.     

Consequences of a low litter birth weight phenotype for postnatal lean growth performance and neonatal testicular morphology in the pig

The consequences of a low litter average birth weight phenotype for postnatal growth performance and carcass quality of all progeny, and testicular development in male offspring, were investigated. Using data from 25 sows with one, and 223 sows with two consecutive farrowing events, individual birth weight (BW) was measured and each litter between 9 and 16 total pigs born was classified as low (LBW), medium (MBW) or high (HBW) birth weight: low and high BW being defined as >1 standard deviation below or above, respectively, the population mean for each litter size. Litter average BW was repeatable within sows. At castration, testicular tissue was collected from 40 male pigs in LBW and HBW litters with individual BW close to their litter average BW and used for histomorphometric analysis. LBW piglets had a lower absolute number of germ cells, Sertoli cells and Leydig cells in their testes and a higher brain : testis weight ratio than HBW piglets. Overall, LBW litters had lower placental weight and higher brain : liver, brain : intestine and brain : Semitendinosus muscle weight ratios than MBW and HBW litters. In the nursery and grow–finish (GF) phase, pigs were kept in pens by BW classification (9 HBW, 17 MBW and 10 LBW pens) with 13 males and 13 females per pen. Average daily gain tended to be lower in LBW than HBW litters in lactation (P = 0.06) and throughout the nursery and GF phases (P < 0.01), resulting in an increasing difference in body weight between LBW, MBW and HBW litters (P < 0.05). Average daily feed intake was lower (P < 0.001) in LBW than HBW litters in the nursery and GF phases. Feed utilization efficiency (feed/gain) was similar for LBW and HBW litters in the nursery, but was lower (P < 0.001) in HBW than LBW litters in the GF phase. By design, slaughter weight was similar between BW classifications; however, LBW litters needed 9 more days to reach the same slaughter weight than HBW litters (P < 0.001). BW classification did not affect carcass composition traits. In conclusion, LBW litters showed benchmarks of intrauterine growth retardation, LBW had a negative impact on testicular development and germ and somatic cell populations, and was associated with decreased postnatal growth during all phases of production; however, no measurable effect on carcass composition traits was established.     

Effects of dietary enrichment with a marine oil-based n-3 LCPUFA supplement in sows with predicted birth weight phenotypes on birth litter quality and growth performance to weaning

The effects of a marine oil-based n-3 long-chain polyunsaturated fatty acid (mLCPUFA) supplement fed to the sow from weaning, through the rebreeding period, during gestation and until end of lactation on litter characteristics from birth until weaning were studied in sows with known litter birth weight phenotypes. It was hypothesized that low birth weight (LBW) litters would benefit more from mLCPUFA supplementation than high birth weight litters. A total of 163 sows (mean parity=4.9±0.9) were rebred after weaning. Sows were pair-matched by parity and litter average birth weight of the previous three litters. Within pairs, sows were allocated to be fed either standard corn/soyabean meal-based gestation and lactation diets (CON), or the same diets enriched with 0.5% of the mLCPUFA supplement at the expense of corn. Each litter between 9 and 16 total pigs born was classified as LBW or medium/high average birth weight (MHBW) litter and there was a significant correlation (P<0.001) between litter average birth weight of the current and previous litters within sows (r=0.49). Sow serum was harvested at day 113 of gestation for determination of immunoglobulin G (IgG) concentrations. The number of pigs born total and alive were lower (P=0.01) in mLCPUFA than CON sows, whereas the number of stillborn and mummified pigs were similar between treatments. Number of stillborns (trend) and mummies (P<0.01) were higher in LBW than MHBW litters. Tissue weights and brain : tissue weight ratios were similar between treatments, but LBW litters had decreased tissue weights and increased brain : tissue weight ratios compared with MHBW litters. Placental weight was lower (P=0.01) in LBW than MHBW litters, but was not different between treatments. Average and total litter weight at day 1 was similar between treatments. mLCPUFA increased weaning weight (P=0.08) and average daily gain (P<0.05) in MHBW litters, but not in LBW litters. Pre-weaning mortality was similar between treatments, but was higher (P<0.01) in LBW than MHBW litters. IgG concentration in sow serum was similar between treatments and litter birth weight categories. In conclusion, litter birth weight phenotype was repeatable within sows and LBW litters showed the benchmarks of intra-uterine growth retardation (lower placental weight and brain sparing effects). As maternal mLCPUFA supplementation decreased litter size overall, only improved litter growth rate until weaning in MHBW litters, and did not affect pre-weaning mortality, maternal mLCPUFA supplementation was not an effective strategy in our study for mitigating negative effects of a LBW litter phenotype.     

Transgenic production from in vivo-derived embryos: effect on calf birth weight and sex ratio

We examined transgenic-cattle production by DNA microinjection into 1-, 2-, and 4-cell embryos, analyzing the impact on calf size and subsequent viability. Embryos were either collected at an abattoir by flushing oviducts from superovulated and artificially inseminated cows (in vivo-derived) or obtained by in vitro maturation and in vitro fertilization of oocytes aspirated from excised ovaries (in vitro-derived). A human serum albumin (hSA) milk-expression DNA construct was microinjected, either in one of the visible pronuclei of in vitro- and in vivo-derived 1-cell embryos or in the nuclei of two blastomeres of 2- and 4-cell in vivo-derived embryos. Microinjection-induced mortality (lysis and developmental block) was equivalent ( approximately 40%) for all microinjected embryos. Embryos were co-cultured with BRL cells in B-2 medium containing 10% fetal calf serum (FSC). Overall, embryo development to morulae/blastocysts was significantly greater for in vivo-derived ova (15.5%) than for in vitro-derived oocytes (9.3%). All morulae and blastocysts were transferred to synchronized recipient females on Days 6-8 post-fertilization. A total of 189 calves were delivered. Birth weights were significantly greater for calves generated from in vitro-derived oocytes compared with those generated from in vivo-derived oocytes. One transgenic bull calf was obtained from the microinjection of a 2-cell embryo. Fluorescence in situ hybridization (FISH) analysis of lymphocytes detected one transgenic integration site in all cells. Transmission frequency of the hSA transgene in embryos obtained through IVM/IVF/IVC utilizing the semen of the transgenic calf confirmed that it was not mosaic.     

Low Birth Weight and Normal Birth Weight Newborns of Kolkata, India: Comparison of Some Maternal Risk Factors

This study compared several maternal risk factors of low birth weight (LBW) between 204 normal birth weight (NBW) and 133 LBW newborns from Kolkata, India. Based on their birth weight (BW), newborns were classified as LBW (BW < 2.5 kg) and NBW (BW ≥ 2.5 kg). Results revealed that means for maternal age (MA, p < 0.05), gestational age (GA, p < 0.01), hemoglobin (Hb) concentration (p < 0.05), and per capita daily income (PCDI, p < 0.05) were significantly higher among mothers of NBW. Correlation analyses revealed that MA (r = 0.119, p < 0.05), GA (r = 0.583, p < 0.01), PCDI (r = 0.118, p < 0.05), and Hb (r = 0.138, p < 0.05) were significantly positively correlated with BW; PCDI was also significantly positively correlated (r = 0.142, p < 0.01) with Hb. Stepwise regression analyses with BW as the dependent variable revealed that GA (t = 7.915, p < 0.001) and Hb (t = 2.057, p < 0.05) were the most important predictive variables. The effect of Hb, independent of GA, was statistically significant (change in F = 4.231, p < 0.05). Because GA is not modifiable in pregnant women, there is a need to increase Hb levels among pregnant mothers. Most importantly, appropriately targeted preventive strategies, including iron supplementation, need to be implemented for health promotion.     

Sources of sire-specific genetic variance for birth and weaning weight in Bruna dels Pirineus beef calves

This research investigated two sources of sire-specific genetic effects on the birth weight (BWT) and weaning weight (WWT) of Bruna dels Pirineus beef calves. More specifically, we focused on the influence of genes located in the non-autosomal region of the Y chromosome and the contribution of paternal imprinting. Our analyses were performed on 8130 BWT and 1245 WWT records from 12 and 2 purebred herds, respectively, they being collected between years 1986 and 2010. All animals included in the study were registered in the Yield Recording Scheme of the Bruna dels Pirineus breed. Both BWT and WWT were analyzed using a univariate linear animal model, and the relevance of paternal imprinting and Y chromosome-linked effects were checked by the deviance information criterion (DIC). In addition to sire-specific and direct genetic effects, our model accounted for random permanent effects (dam and herd-year-season) and three systematic sources of variation, that is, sex of the calf (male or female), age of the dam at calving (six levels) and birth type (single or twin). Both weight traits evidenced remarkable effects from the Y chromosome, whereas paternal imprinting was only revealed in WWT. Note that differences in DIC between the preferred model and the remaining ones exceed 39 000 and 2 800 000 DIC units for BWT and WWT, respectively. It is important to highlight that Y chromosome accounted for ∼2% and ∼6% of the total phenotypic variance for BWT and WWT, respectively, and paternal imprinting accounted for ∼13% of the phenotypic variance for WWT. These results revealed two relevant sources of sire-specific genetic variability with potential contributions to the current breeding scheme of the Bruna dels Pirineus beef cattle breed; moreover, these sire-specific effects could be included in other beef cattle breeding programs or, at least, they must be considered and appropriately analyzed.