Investigation of the insulin-like growth factor system in the avian epiphyseal growth plate

Components of the insulin-like growth factor (IGF) system were investigated in chondrocytes isolated from the avian growth plate. The genes for IGF-I, IGF-II, type 1 IGF receptor (IGF-R), IGF binding protein-2 (IGFBP-2), IGFBP-3, IGFBP-5 and IGFBP-7 were found to be expressed in both proliferative and hypertrophic chondrocytes. The expression of IGF-II in proliferative chondrocytes was extremely high relative to IGF-I. Although IGF-I expression was significantly increased in hypertrophic chondrocytes, the level was still low relative to IGF-II. In cell culture, IGF-I stimulated proteoglycan synthesis and increased the expression of Indian hedgehog (Ihh) and type X collagen, markers of chondrocyte differentiation. IGF-II was found to be equally efficacious in stimulating proteoglycan biosynthesis. These observations suggest that IGF-II may play a significant role in avian growth plate physiology, which is consistent with several reports on mammalian endochondral bone growth.     

KIT-KIT ligand in the growth of porcine oocytes in primordial follicles

Mammalian ovaries are endowed with a huge number of small oocytes in primordial follicles (primordial oocytes). The mechanism regulating initiation of oocyte growth and follicular development is not well understood. Several growth factors and cytokines are known to be involved in oocyte growth and follicular development. Herein, the involvement of KIT, a receptor tyrosine kinase, and its ligand, KIT ligand (KL), in the initiation of porcine oocyte growth was examined. At first, KIT expression was examined immunohistochemically in primordial oocytes from neonatal (10-20 days) and prepubertal (about 6 months) pigs. Similar expression of KIT was detected in all oocytes from both the neonatal and prepubertal pigs. Next, to examine the growth of primordial oocytes, ovarian tissues containing primordial oocytes were xenotransplanted into immunodeficient SCID mice. Primordial oocytes from the neonatal pigs grew with follicular development as described previously, whereas those from the prepubertal pigs did not initiate growth in the xenografts after 2 months. To stimulate the growth of primordial oocytes from the prepubertal pigs, they were cultured in a medium supplemented with KL (50 and 100 ng/ml) for 1 or 3 days before xenografting. After 2 months, however, the oocytes did not grow, and the primordial follicles did not develop, although a higher number of primordial oocytes survived in the KL-treated tissues. These results suggest that KIT-KL might not be associated with the growth initiation of porcine primordial oocytes, although they do enhance the survival of the oocytes.     

刈割对羊草和全叶马兰生长与种间关系的影响

研究刈割对羊草(Leymus chinensis)和全叶马兰(Kalimeris integrifolia)生长与种间关系的影响。结果表明:刈割强度越大,相对生长速率越大;留茬4.8和12cm之间差异显著;刈割改变植物间相互作用的方向,削弱种间关系在群落中的重要性;刈割对羊草生长的影响较大。     

Endocrine and histologic correlates of the dynamics of the metacarpal growth plate in growing rams

The objective was to study control of mature size by characterizing metacarpal growth plate closure in relation to relevant bone growth-regulating hormones in two breeds exhibiting distinct differences in mature frame size. Thirty-four Suffolk and 34 Dorset ram lambs were slaughtered in pairs within breed at birth, weaning and monthly intervals until 420 d and then bimonthly to 600 d. Plasma growth hormone was depressed to undetectable levels due to the high-energy, ad libitum-fed diet. Plasma insulin-like growth factor-I (IGF-I) rose over the growth period from 116 ng/ml (newborn Suffolk) to a high of 451 ng/ml (420-d Dorset); it appeared to peak at approximately 400 d and then declined to a stable level. Dorsets consistently exhibited higher IGF-I levels. The thyroid hormones exhibited no apparent age association. An age-associated rise was detected for testosterone, but not for estradiol. Mature metacarpal lengths were estimated to be 147.2 and 127.4 mm for Suffolks and Dorsets, respectively. Ninety-five percent of mature length was attained in Suffolks by 226 d and in Dorsets by 165 d. Growth plates, however, did not begin to appear closed until 390 d and closure was not complete in all animals until 480 d, suggesting that metacarpal growth rate was dissociated temporally from growth plate closure. Although growth plate closure likely is controlled by the endocrine system, there were no apparent relationships between circulating hormones and growth plate width, age at closure or zonal divisions within the growth plate, suggesting that the growth plate experiences a very different hormonal environment than what can be measured in the circulating blood.     

Effect of experimental therapeutic ultrasound on the distal antebrachial growth plates in one-month-old rabbits

The effect of therapeutic ultrasound (US) on the growth plates of growing bone was determined through fluorescence labelling and histopathological evaluation in one-month-old rabbits. Mean growth rates and mean heights of the growth plates of the US exposed radius vs. control radius, and US exposed ulna vs. control ulna showed no statistically significant differences at all intensities and time intervals. Mean growth rates and heights of the growth plates of the US exposed radius for 0.2 W/cm(2) (SATA) US vs. 0.5 W/cm(2) US showed the same type of pattern compared to those of the control radius for 0.2 W/cm(2)vs. 0.5 W/cm(2) at days 10, 15 and 20. Similar results were also found for the ulna. Effects of 0.5 W/cm(2) US on the mean growth rates and mean heights of the growth plates were superior to those of 0.2 W/cm(2) US at day 10. The results at day 10 were reversed for the same comparisons at days 15 and 20. No cavitation effect of US was observed on growth plate cells. There was no evidence of partial or complete premature closure of the growth plates or of angular deformity of the carpal region.     

典型草原亚洲小车蝗危害对植物补偿生长的作用

以内蒙古典型草原亚洲小车蝗Oedaleus asiaticus为对象,通过田间罩笼和人工模拟取食2种方式,比较了亚洲小车蝗4个龄期及3种密度下对典型草原不同植物补偿性生长反应的特点。结果表明,3龄、4龄期罩笼试验地上生物量高于模拟取食(P<0.05),5龄、成虫罩笼试验地上生物量显著低于模拟取食试验(P<0.05),说明亚洲小车蝗的取食对植物生长存在明显的补偿生长作用。5龄亚洲小车蝗密度小于16头/m2时,地上生物量与对照间差异不显著(P>0.05),植物表现等补偿生长;成虫亚洲小车蝗密度大于4头/m2时,地上生物量显著低于对照区(P<0.05),植物表现欠补偿生长;3龄、4龄亚洲小车蝗密度大于4头/m2时,地上生物量显著高于对照区(P<0.05),植物表现超补偿生长。亚洲小车蝗3、4龄期,羊草Ley-mus chinensis和冷蒿Artemisia frigida出现超补偿生长,其他植物种群均出现等补偿生长;5龄和成虫期随密度增加,均出现欠补偿生长。     

我国退牧还草工程重点县草原植被长势遥感监测

利用遥感和地理信息系统等先进技术手段,基于MODIS数据,对我国4大主要草地类型区的退牧还草工程县的草原植被长势进行了监测,主要结论如下:1)内蒙古东部退化草原区2005年草原植被长势虽然差于2004年的面积有上升趋势,但是总体长势良好,明显好于2004年;2)蒙甘宁西部荒漠草原区2005年草原植被长势较差,虽然生长季节草原植被长势差于2004年的面积呈上升趋势,但总体相对比较稳定;3)新疆北部退化草原区2005与2004年相比长势持平的草地面积所占比重大,比较稳定,呈现出长势好差交替的时序变化格局;4)青藏高原东部江河源草原区2005年草原长势好于2004年的草地面积占本区总草地面积的48.07%,长势差于2004年的草地面积占本区草地总面积的32.56%,与2004年持平的占19.37%,由此表明青藏高原东部区草原长势明显好于2004年同期,长势差和长势好于2004年的草原面积波动较为明显。     

Bacterial growth during the early phase of infection determines the severity of experimental Escherichia coli mastitis in dairy cows

The aim of this study was to investigate the importance of bacterial growth for the severity of experimental Escherichia coli mastitis, indirectly expressed as the area under the curve of bacterial counts in milk over time. The association of pre-infusion somatic cell count and post-infusion influx of inflammatory cells in milk with severity of infection was also examined. Bacterial growth was studied through culture in milk samples (in vitro) and through monitoring of bacterial counts in milk during the early phase of infection (in vivo) in 36 cows. Individual variation in bacterial counts was more than 2 x 10(2)-fold after 6 h of in vitro incubation, and more than 8 x 10(2)-fold 6 h after intramammary infusion. In vitro growth in milk was not associated with in vivo growth during the early phase of infection, nor with severity of E. coli mastitis. Somatic cell count before experimental E. coli mastitis was negatively associated with in vivo bacterial growth during the early phase of infection (R2 = 0.28), but was not associated with severity of E. coli mastitis (R2 = 0.06). In vivo bacterial growth during the early phase of infection (positive association; R2 = 0.41), together with influx of inflammatory cells in milk, expressed as mean hourly increase of somatic cell count between 6 and 12 h post-infusion (negative association; R2 = 0.11), are major determinants for the severity of experimental E. coli mastitis (R2 = 0.56).     

肉鸡胫骨软骨发育不良早期钙黏蛋白1(CDH1)差异表达研究

为研究福美双诱发肉鸡胫骨软骨发育不良(Tibial Dyschondroplasia,TD)早期钙黏蛋白1(CDH1)的差异表达,基础日粮中添加福美双,在试验第1、2、6天,对试验鸡进行剖杀,迅速采取胫骨生长板故入4％多聚甲醛溶液于4℃固定,做CDH1免疫组化分析;提取对照组和饲喂福美双组的生长板总RNA,采用Real-time PCR对CDH1 基因进行差异表达验证.结果钙黏蛋白1 (CDH1/E-cadherin)基因在TD生长板表达上调,在对照和TD软骨生长板,其蛋白合成主要在前肥大、肥大区软骨细胞质,增殖区软骨细胞无表达,钙化区软骨细胞表达少,在饲喂福美双第1、2、6天其表达增加与定量PCR变化结果相一致,且在饲喂福美双第2、6天呈明显高表达.结果表明CDH1 参与细胞黏附、血管入侵及调节Wnt/β-cat的信号传递,和其它分子共同调节软骨内骨化.     

Evaluation of osteoinduction properties of the demineralized bovine foetal growth plate powder as a new xenogenic biomaterial in rat

The aim of this study was evaluation of osteoinductive properties of demineralized bovine foetal growth plate in submuscular transplantation (ectopic osteoinduction) as a new xenogenic biomaterial in rat model. Demineralized bovine foetal growth plate was ectopically implanted in 18 male Sprague–Dawley rats. In 18 of the animals under aseptic conditions two submuscular pouches were created between external and internal oblique abdominal muscles in the two flanks: the right was left empty (sham) and the left was filled with 20 mg of demineralized bovine foetal growth plate powder. Radiographs were taken in 2, 4 and 6 weeks after the surgery, then six animals were pharmacologically euthanized after 2, 4 and 6 weeks for histopathological evaluation. Results showed: (1) osteoinductivity of xenogenic demineralized bovine foetal growth plate powder, and (2) earlier mineralization of ectopically implanted demineralized bovine foetal growth plate in the submuscular implanted area. Our results show that submuscular implantation of xenogenic demineralized bovine foetal growth plate has osteoinductive properties in a rat model.     

Changes in the muscle proteome after compensatory growth in pigs

Sixteen female pigs (Duroc x Landrace x Large White) were divided into 2 groups, which had either free access to the diet (control group) or were feed-restricted from d 28 to 80 and then had free access to the diet (compensatory growth group). The sensory analysis showed that the pigs exhibiting compensatory growth produced meat with increased tenderness compared with control pigs (P < 0.05). To gain further knowledge of the influence of compensatory growth on meat tenderness, the sarcoplasmic protein fraction of muscle tissue was studied at the time of slaughter and 48 h postmortem using proteome analysis. At slaughter, 7 different proteins were found to be affected by compensatory growth: HSC70, HSP27, enolase 3, glycerol-3-phosphate dehydrogenase, aldehyde dehydrogenase E2, aldehyde dehydrogenase E3, and biphosphoglycerate mutase. The HSC70 and HSP27 both belong to the heat shock family and are known to play a role during muscle development. Hence, they may be affected by compensatory growth and increased protein turnover. Forty-eight hours after slaughter, 8 different proteins were found to be affected by compensatory growth: myosin light chain (MLC) II, MLC III, sulfite oxidase, chloride intracellular channel 1, 14-3-3 protein gamma, elongin B, and phosphohistidine phosphatase 14. The changes observed on MLC II and MLC III could be a consequence of enzymatic cleavage in the neck region of the globular myosin head domain that causes the release of MLC II and MLC III from the actomyosin complex. It has previously been hypothesized that compensatory growth results in an increased postmortem proteolysis; thus it was presumed that the intensity of some protein fragments would be affected by compensatory growth. However, the peptides that were found to be affected at 48 h postmortem were all full-length proteins. The 14-3-3 protein gamma has been proposed to play a role in the contraction of muscle during rigor and may thereby have an effect on meat tenderness. This study reveals some very interesting changes in the muscle proteome affected by compensatory growth, which may be useful in understanding the relationship among compensatory growth, protein turnover, and meat tenderness.     

Analysis of the mouse high-growth region in pigs

In the mouse, homozygous animals for the high growth mutation show a 30–50% increase in growth without becoming obese. This region is homologous to the distal part of pig chromosome 5 (SSC5). A previous genome scan detected several quantitative trait loci (QTL) in this region for body composition and meat quality using a three generation Berkshire × Yorkshire resource family. In this study, the effects on swine growth, fat and meat quality traits of three genes previously identified within the mouse high growth region were analysed. The genes studied were CASP2 and RIPKI domain containing adaptor with death domain ( CRADD ), suppressor of cytokine signalling 2 ( SOCS2 ) and plexinC1 ( PLXNC1 ). In addition, the influence of two other genes located very close to this region, namely the plasma membrane calcium-transporting ATPase 1 ( ATP2B1 ) and dual specificity phosphatase 6 ( DUSP6 ) genes, was also investigated. Single nucleotide polymorphisms were identified and used to map these genes to the QTL region on SSC5. Results indicate significant associations between these genes and several phenotypic traits, including fat deposition and growth in pigs. The present study suggests associations of these genes with swine fat and growth related traits, but further studies are needed in order to clearly identify the genes involved in the regulation of the QTL located on SSC5.     

The effects of the primary growth of two ryegrasses on the dynamics of changes in digestibility and feed intake by sheep

Dynamics of changes in digestibility and feed intake by sheep of two ryegrass species during primary growth Environmental impacts can cause short-term variations in chemical composition and feeding value of grass swards during growth and maturation and induce concomitant changes of intake of these grasses by animals. Continuous digestion trials are effective in observing the dynamics of these variations. Therefore this study was conducted to evaluate the effects of maturity-related alterations in the chemical composition of two ryegrass swards during primary growth on nutrient digestibilities and feed intake by sheep. Pure swards of perennial ryegrass (Lolium perenne L., variety Gremie) and Italian ryegrass (Lolium multiflorum Lam., variety Lema) were harvested daily during primary spring growth between 23 April and 19 June 1991 and each grass was offered to a group of five sheep for ad libitum intake. A continuous digestion trial design was employed to measure daily intakes and faecal outputs of organic matter (OM) and OM constituents. Digestibility values were calculated with the assumption that faecal output of day 2 represented the undigested nutrients of the grass eaten at day 0. Based on results of a preliminary study, daily intakes and digestibilities were expressed as rolling 3-day averages. The chemical composition of the grasses varied considerably with growth. Crude protein concentrations declined from 18.3 to 5.9% of dry matter (DM) for perennial ryegrass and from 17.0 to 5.4% of DM for Italian ryegrass, whereas concentrations of some cell-wall fractions markedly increased and partly more than doubled. Fibre content was slightly greater for perennial ryegrass than for Italian ryegrass over the whole growth period. The decline of feeding value with maturity was closely related to increasing concentrations of fibre components and their declining digestibility. Intake by sheep of Italian ryegrass was higher by 3 g/kg of body weight at the beginning and at the end of the primary growth period. Digestibility of the OM was greater than 80% at the start of the experiment and still around 70% after 2 months of grass growth. The decline in DM and metabolizable energy intake was much more pronounced than the decrease of OM digestibility. This could be attributed in part to a decline in feed intake capacity of non-lactating sheep caused by increasing body fat mass. Short-term fluctuations in OM digestibilities were related to alterations of chemical composition of the grasses caused by growth and maturation, in particular variations in water-soluble carbohydrate concentrations. The two ryegrass species differed with regard to nitrogen associated with the cell-wall (NDF) and lignocellulose (ADF). Continuous digestion trials were effective in observing the dynamics of alterations in feeding value and feed intake by sheep as related to growth and maturation of two ryegrass species during primary spring growth.     

Physical and chemical components of the empty body during compensatory growth in beef steers

The composition of carcass and noncarcass tissue growth was quantified by serial slaughter of 26 Angus x Hereford crossbred steers (initial age and weight 289 +/- 4 d and 245 +/- 4 kg) during continuous growth (CON) or compensatory growth (CG) after a period of growth restriction (.4 kg/d) from 245 to 325 kg BW. All steers were fed a 70% concentrate diet at ad libitum or restricted levels. Homogenized samples of 9-10-11th rib and noncarcass tissues were analyzed for nitrogen, fat, ash, and moisture. Growth rate from 325 to 500 kg BW was 1.54 and 1.16 kg/d for CG and CON steers. The weight of gut fill in CG steers was 10.8 kg less (P less than .05) before realimentation and 8.8 kg more (P less than .10) at 500 kg BW than in CON steers. The allometric accretive rates for carcass chemical components relative to the empty body were not affected by treatment. However, the accretive rates for CG steers were greater (P less than .01) for noncarcass protein (.821 vs .265), noncarcass water (.861 vs .507), and empty-body protein (.835 vs. .601) than for CON steers. Final empty-body fat was lower (P less than .001; 24.2 vs 32.4%) and empty-body protein higher (P less than .001; 16.6 vs 14.8%) in CG steers than in CON steers. Consequently, net energy requirements for growth (NEg) were approximately 18% lower for CG steers. We conclude that reduced NEg requirements and changes in gut fill accounted for most of the compensatory growth response exhibited in these steers.     

Quantitative analysis of long-bone growth in the horse

Long-bone growth at the distal ends of the radial bones, the distal ends of the 3rd metacarpal bones, the distal ends of the 3rd metatarsal bones, and the proximal ends of the proximal phalangeal bones (of thoracic and pelvic limbs) was quantitatively analyzed in 9 Thoroughbred-Quarter Horse foals from birth to 2 years of age. Metal growth markers were surgically implanted in the bones of the animals at 2 to 4 days of age. Radiographs of the bones were made on the day of surgical manipulation, the next day, and then once a week for 8 months, and once a month thereafter for an additional 18 months. On each radiograph, the intervals between the growth markers were measured and plotted, and these accumulated growth data were subjected to statistical analyses. Growth curves, cumulative growth, and relative growth rates were determined. The ages of radiographic growth plate closure also were determined. Total bone growth observed in these foals was proportionately greater than that observed in a similar study of Shetland-Welsh ponies, probably indicating a breed difference. The most rapid growth rate at the 5 anatomic sites in the foals occurred from birth to 10 weeks of age; however, in the distal part of the radius, there was a continuous, though declining growth rate until 60 weeks of age, whereas in the distal ends of the 3rd metacarpal and metatarsal bones and the proximal end of the proximal phalanges growth ceased abruptly and nearly plateaued after 10 weeks of age.(ABSTRACT TRUNCATED AT 250 WORDS)     

施肥对黔中地区混播草地牧草生长性能的影响

本文研究了氮磷钾不同配比施肥量对黑麦草和紫花苜蓿混播草地牧草生长的影响,结果表明:氮肥促进禾本科牧草叶的生长(P<0.05),增施钾肥对禾草的生长有利;磷能促进豆科牧草根的生长(P<0.05)且豆科牧草株高随着施磷量的增加各处理间差异显著(P<0.05),高氮抑制豆科牧草的生长;最高产量的施肥方式:N:P_2O_5:K_2O为20:30:20,比对照处理的草地产量增加63.92％。     

同一蛋白质水平不同赖氨酸与蛋氨酸比例对早期断奶藏羔羊复胃发育的影响

试验旨在研究18%蛋白质水平下,不同赖氨酸与蛋氨酸比例(Lys/Met)对早期断奶藏羔羊复胃发育的影响。选取(55±2)日龄断奶、体重(10.85±0.65)kg藏羔羊42只,随机分为3组,每组14只,公、母各半,分别饲喂18%蛋白质水平下不同Lys/Met比例的羔羊早期断奶料,试验期20 d。对早期断奶藏羔羊各胃室重量和组织形态指标进行了测定。结果表明,Lys/Met比例为3.1∶1时,藏羔羊复胃和瘤胃增重最好,瘤网胃乳头增长,瓣胃角化层、黏膜上皮和中央肌层增厚,皱胃胃底腺黏膜增厚效果最好。提示,早期断奶料营养水平影响藏羔羊复胃的生长发育,适宜的Lys/Met比例能够促进其良好的生长发育,在18%蛋白质水平下,藏羔羊早期断奶料Lys/Met比例为3.1∶1时效果最佳。     

不同生长年限威宁草芦营养成分动态研究

对生长1~4年的威宁草芦牧草新品种不同生育时期营养成分进行动态测定。结果表明:不同生长年限威宁草芦的蛋白质、粗灰分含量都是随着生育时期的推后呈线性下降(P<0.05),酸性洗涤纤维和粗脂肪含量随着生育时期的推后呈线性上升(P<0.05),无氮浸出物的含量变化与生育期无明显相关,粗蛋白含量随着生长年限的推后逐渐下降,而磷、钙含量则以四年生最高;1~4年生分蘖期至抽穗期粗蛋白含量在13.42%~16.96%之间,而粗纤维含量在21.03%~32.88%之间,是西南地区优质地方牧草新品种,具有广泛的推广应用前景。     

三江源地区草地植物功能性状与蒸散发关系研究

蒸散发作为调控区域水分收支的重要支出项,受植物性状的影响。本研究于2021年5月—2021年9月对三江源及其周边共5个区域(海晏(HY)、同德(TD)、玛多(MD)、曲麻莱(QML)、可可西里(KKXL))的实际蒸散发及植被数据进行收集,通过相关性分析解释植被变化过程对环境的适应策略。结果表明：三江源草地植物多以丛生或密丛生为主,其中比叶面积与株高、叶片干物质含量、生长型和种子类型间呈显著负相关(P<0.05)。生长季实际蒸散发日、月动态在5个区域均呈现单峰变化趋势,生长季累积量为HY(309.97 mm)>TD(279.58 mm)>QML(247.90 mm)>MD(239.42 mm)>KKXL(230.35 mm)。分析植物功能性状与实际蒸散发之间的相关性,表明株高、比叶面积、叶片干物质含量、生长型和种子类型均与实际蒸散发呈现一定相关性,其中生长型相关性最大(R²=0.74)。     

Influence of cysteine in conjunction with growth factors on the development of in vitro-produced bovine embryos

Cysteine supplementation to in vitro maturation (IVM) media of bovine oocytes increases cellular glutathione production. Beneficial effects of growth factors for improving the rate of blastocyst development have been reported, but combined effects are unknown. This study was conducted to determine the additive effect of cysteine with epidermal growth factor (EGF) and/or insulin-like growth factor-I (IGF-I) on embryo development. Bovine oocytes from slaughterhouse ovaries were matured in TCM-199 (control), with or without the addition of 0.6 mm cysteine (C) at 0 or 12 h of maturation. After in vitro fertilization, embryos were allocated to culture treatments containing synthetic oviductal fluid medium. Culture treatments included fetal calf serum (FCS, 4%) alone; IGF-I (100 ng/ml); EGF (10 ng/ml); and IGF-I + EGF (100 + 10 ng/ml). Although rates for blastocysts development were not different among treatments, an increased proportion of embryos attaining morula formation was achieved when cysteine was added to the maturation media (12 h C IGF-I + EGF, 41.4%; 0 h C EGF, 40.0%) as compared to control (FCS: 34.6%). When cysteine treatments were combined, percent cleavage was greater for IGF-I + EGF (70.8%) compared to FCS (61.2%). The abundance of mRNA from the apoptotic genes, Bax and Bcl-2, and the oxidative stress genes, copper (Cu)-zinc (Zn) superoxide dismutase (SOD) and manganese (Mn) SOD in embryos was assessed. No treatment effect was observed on the expression of these genes. In conclusion, supplementation of cysteine during IVM of oocytes, in conjunction with growth factors could effectively be used as a replacement for FCS.