重组生长因子对早期断奶仔猪小肠黏膜形态和二糖酶活性的影响

旨在研究表达表皮生长因子(EGF)的乳酸菌对早期断奶仔猪小肠的组织形态与肠黏膜二糖酶活性的影响。选取21日龄体重相近的仔猪108头分4个处理组,每组3个重复,每个重复9头,4个处理组按2×2分组设计,即高质量料+EGF组(HE)、高质量料组(HM)、低质量料+EGF组(LE)和低质量料组(LM)4个处理。HE、LE两组从断奶的当天开始每日饮用含基因工程表达的猪EGF(pEGF)及其转基因乳酸球菌(EGF-Lactococcus lactis,EGF-LL)的M17培养液,HM、LM两组则仅给予同样剂量的M17培养液。在试验的第15天,从每个处理中随机抽取6头(共24头)屠宰测定试验猪肠绒毛高度、隐窝深度和肠黏膜二糖酶的活性。结果:LE组的空肠绒毛高度(V)、隐窝深度(C)及绒毛高度/隐窝深度(V/C)均极显著地大于LM组(P<0.01),HE组的隐窝深度和V/C显著大于HM组;LE和HE组空肠处的乳糖酶和蔗糖酶活性均显著高于LM组(P<0.01),十二指肠处HE组乳糖酶活性极显著地高于LM组(P<0.01),空肠处LE组的乳糖酶活性显著高于HM组(P<0.05),LE组的小肠黏膜形态和二糖酶活性与HM组相差不大。结果表明口服表达EGF的乳酸菌可以改善断奶仔猪小肠形态,提高小肠消化酶的活性,对空肠的影响尤为显著,其效果和血浆蛋白粉的相类似。     

重组表皮生长因子对仔猪小肠上皮细胞增殖活性的影响

通过口服血浆蛋白粉以及表达和传递表皮生长因子(EGF)的乳酸球菌(EGF-LL),以检验在断奶关键期重组猪EGF促进小肠黏膜细胞增殖活性、改善胃肠道形态、降低肠绒毛萎缩的可行性,探讨EGF-LL替代血浆蛋白粉的可能性。选取21日龄体重相近的仔猪108头分4个处理组,每组3个重复,每个重复9头,4个处理组按2×2分组设计,即高质量饲料+EGF-LL组(HE)、高质量饲料组(HM)、低质量饲料+EGFLL组(LE)和低质量饲料组(LM),以组织学方法测试各组小肠绒毛和隐窝长度以及绒毛和隐窝上皮细胞增殖细胞核抗原(PCNA)含量。结果:前3组十二指肠和空肠的绒毛高度均显著高于LM组(P0.05),单独添加血浆蛋白粉也具有显著的促进作用。而对于小肠隐窝深度的影响,则是添加EGF-LL较不添加的深度显著变小(P0.05),单独添加血浆蛋白粉对其影响不大。添加EGF-LL使得小肠隐窝PCNA含量显著增加,却使得小肠绒毛上皮PCNA含量显著下降。单独添加血浆蛋白粉显著促进小肠隐窝PCNA含量,但对于小肠绒毛上皮PCNA含量没有显著影响。本试验结果表明,以乳酸球菌为载体向早期断奶仔猪胃肠道传递EGF,可以促进早期断奶仔猪小肠绒毛的发育和上皮细胞的分化,增强小肠上皮干细胞的分裂增殖能力,血浆蛋白粉也有上述作用,饲料添加EGF-LL可以替代血浆蛋白粉。     

断奶腹泻仔猪小肠病理变化观察

目的:研究断奶腹泻仔猪小肠病变,以期为临床防治断奶仔猪腹泻提供理论依据.方法:断奶腹泻仔猪及健康仔猪各4头,处死后观察小肠病变及通过显微测微尺测定小肠绒毛高度和隐窝深度.结果:(1)腹泻仔猪小肠发生广泛充血、出血,黏膜上皮细胞变性、坏死和大量炎性细胞浸润;(2)腹泻仔猪十二指肠、空肠、回肠的小肠绒毛出血率均极显著高于健康组(P<0.01);(3)腹泻仔猪空肠绒毛高度均显著低于健康组(P<0.05),隐窝深度显著高于健康组(P<0.05),绒毛高度/隐窝深度值极显著小于健康组(P<0.01).结论:断奶仔猪腹泻造成小肠严重的病变和功能障碍.     

纳米载铜蒙脱石对断奶仔猪腹泻、肠道菌群及肠粘膜形态的影响

选用96头健康“杜长大“三元杂交断奶仔猪,随机分为3组,每组8头,设4个重复,分别饲喂基础日粮(对照组)、基础日粮 2.0g/kg纳米蒙脱石(MMT)、基础日粮 2.0g/kg纳米载铜蒙脱石(MMT-Cu),研究了MMT-Cu对断奶仔猪腹泻、肠道菌群及其肠粘膜形态的影响.结果表明,与对照组相比,饲料中添加2.0g/kg MMT-cu,能显著(P＜0.05)提高断奶仔猪的平均日增重和饲料转化效率,显著降低腹泻率(P＜0.05);显著降低(P＜0.05)小肠和结肠内容物中大肠杆菌和沙门氏菌的数量;显著提高(P＜0.05)小肠绒毛高度和绒毛高度与隐窝深度的比值;显著提高(P＜0.05)十二指肠微绒毛高度.与对照组相比,添加2.0g/kg MMT也能显著降低断奶仔猪腹泻率(P＜0.05),提高(P＜0.05)小肠绒毛高度和绒毛高度与隐窝深度的比值,但对于断奶仔猪的生长性能和肠道菌群无显著影响(P＞0.05).与添加2.0g/kg MMT相比,添加2.0g/kg MMT-Cu能显著降低(P＜0.05)小肠和结肠内容物中大肠杆菌和沙门氏菌的数量.     

蛋氨酸羟基类似物对断奶仔猪生长性能和小肠形态的影响

文章旨在评估日粮添加不同水平的蛋氨酸羟基类似物对断奶仔猪生长性能、小肠绒毛形态及盲肠微生物数量和挥发性脂肪酸浓度的影响。试验选择21?d断奶平均体重为（6.14±0.05）kg的仔猪600头,随机为3组,每组5个重复,每个重复40头。对照组饲喂基础日粮,处理组日粮分别在基础日粮中添加0.1%和0.2%蛋氨酸羟基类似物,试验从断奶当天开展到断奶后28?d。结果：与对照组相比,处理1和2组仔猪的末重分别显著提高4.97%和3.20%（P＜0.05）,处理1组仔猪平均日增重较对照组显著提高9.31%（P＜0.05）。对照组仔猪料重比较处理组分别显著提高5.33%和4.14%（P＜0.05）。处理1组仔猪空肠绒毛高度显著高于对照组和处理2组（P＜0.05）,但对照组空肠隐窝深度较处理2组显著提高12.54%（P＜0.05）,处理1组仔猪空肠绒毛高度与隐窝深度的比值较对照组显著显著提高19.31%（P＜0.05）。处理1组仔猪回肠隐窝深度显著高于处理2组（P＜0.05）,而处理2组仔猪回肠绒毛高度与隐窝深度比值显著高于对照组和处理1组（P＜0.05）。处理1组盲肠乳酸杆菌数量、戊酸浓度显著高于对照组和处理2组（P＜0.05）,而对照组盲肠短链脂肪酸浓度和乙酸浓度显著低于处理组（P＜0.05）。结论：日粮添加0.1%蛋氨酸羟基类似物可以提高断奶后28?d仔猪的生长性能,改善空肠和回肠绒毛形态。 [关键词]蛋氨酸羟基类似物|断奶仔猪|生长性能|小肠形态     

断奶应激对仔猪肠形态、肠黏膜屏障和p38丝裂原活化蛋白激酶信号通路的影响

本试验旨在研究早期断奶仔猪肠黏膜屏障变化及其对p38丝裂原活化蛋白激酶(p38MAPK)信号通路的影响。选取21日龄"杜×长×大"仔猪12窝,每窝选取2～3头平均体重为(5.8±0.4)kg的仔猪断奶,为断奶组,每窝剩下的仔猪不断奶继续哺乳至35日龄,为哺乳组,分别于仔猪22、24、28和35日龄屠宰取样,每次每组6头。结果表明:与哺乳组相比,断奶组空肠绒毛高度和绒毛高度/隐窝深度在22、24和28日龄均显著降低(P<0.05),隐窝深度均显著提高(P<0.05),35日龄上述指标断奶组与哺乳组差异不显著(P>0.05)。断奶组在断奶后的不同时间肠形态发生了变化,断奶仔猪24和28日龄空肠绒毛高度/隐窝深度显著低于22日龄(P<0.05),35日龄断奶仔猪空肠绒毛高度和绒毛高度/隐窝深度显著高于22、24和28日龄(P<0.05)。与哺乳组相比,血浆D-乳酸含量和二胺氧化酶活性在断奶后不同时间均显著提高(P<0.05),35日龄断奶组仍显著高于哺乳组(P<0.05)。与22日龄断奶仔猪相比,24日龄p38 MAPK磷酸化水平与总水平的比值显著增加(P<0.05),并达到高峰,随后此比值随着日龄的延长逐渐降低。结果提示,21日龄仔猪断奶后肠形态和肠黏膜屏障受损,在35日龄肠形态基本恢复,但是肠道通透性仍未恢复,仔猪断奶后肠道通透性的恢复滞后于形态学重建,断奶应激激活了p38 MAPK信号通路。     

苯甲酸对细菌性腹泻断奶仔猪生长性能及肠道健康的影响

文章旨在评估日粮补充苯甲酸对感染细菌性腹泻断奶仔猪生长性能及肠道健康的影响。试验将21 d断奶、平均体重为（6.31±0.12）kg的684头仔猪随机分为3组,每组6个重复,每个重复38头。对照组饲喂基础日粮（未感染细菌性腹泻）,感染组仔猪饲喂基础日粮,在断奶后7 d接种大肠杆菌K88 105 CFU/头,苯甲酸组饲喂基础日粮+5 kg/t苯甲酸,在断奶后7 d接种大肠杆菌K88 105 CFU/头。结果：对照组仔猪断奶后21 d的体重、1～21 d平均日增重显著高于感染组和苯甲酸组（P＜0.05）,同时,1～21 d饲料报酬显著高于感染组（P＜0.05）。对照组和苯甲酸组仔猪断奶后42 d体重、22～42 d和1～42 d日增重、饲料报酬均显著高于感染组（P＜0.05）。与感染组相比,对照组和苯甲酸组仔猪断奶后1～42 d的腹泻率分别显著降低29.93%和17.70%（P＜0.05）。甲酸组仔猪断奶后42 d空肠pH较感染组显著降低7.48%（P＜0.05）,同时回肠pH较对照组和感染组分别显著降低6.09%和5.67%（P＜0.05）。感染组十二指肠绒毛高度与隐窝深度比值、空肠隐窝深度显著低于对照组和苯甲酸组（P＜0.05）。苯甲酸组回肠隐窝深度较感染组显著提高16.89%（P＜0.05）,而绒毛高度较对照组和感染组分别显著提高12.63%和13.92%（P＜0.05）。结论：在本试验条件下,日粮添加5 g/kg苯甲酸可以降低细菌性腹泻对断奶仔猪生长性能的负面作用和腹泻率,同时可以降低回肠pH,改善回肠绒毛高度和隐窝深度。 [关键词]苯甲酸|腹泻|断奶仔猪|生长性能|肠道健康     

益生菌制剂对早期断奶仔猪肠道pH、黏膜形态结构和挥发性脂肪酸含量的影响

本试验旨在研究益生菌制剂对早期断奶仔猪肠道pH、黏膜形态结构和挥发性脂肪酸含量的影响.选用48头平均体重为(6.39±0.42)kg的(21±2)日龄“杜×长×大”三元杂交断奶仔猪,按性别、体重和窝源基本一致原则随机分为2个组,每个组4个重复,每个重复6头猪.试验1组为对照组,采用基础饲粮;试验2组为益生菌组,每千克基础饲粮中添加1×109 CFU活菌.试验期为21d.结果表明:1)28日龄时,益生菌组回肠内容物pH显著低于对照组(P＜0.05).2)和对照组相比,添加益生菌制剂,28日龄时,显著增加空肠、回肠绒毛高度和上皮内淋巴细胞数量(P＜0.05),显著提高回肠杯状细胞数量(P＜0.05),显著降低回肠隐窝深度(P＜0.05);35日龄时,显著增加空肠、回肠绒毛高度(P＜0.05),显著提高空肠上皮内淋巴细胞数量(P＜0.05),显著降低空肠、回肠隐窝深度(P＜0.05);42日龄时,显著增加空肠、回肠绒毛高度,显著提高空肠上皮内淋巴细胞和杯状细胞数量(P＜0.05),显著降低空肠隐窝深度(P＜0.05).3)28日龄时,益生菌组盲肠内容物中丁酸和乳酸含量显著高于对照组(P＜0.05);35日龄和42日龄时,益生菌组盲肠内容物中乙酸、丙酸、丁酸和乳酸含量显著高于对照组(P＜0.05).由结果可知,添加益生菌制剂能改善断奶应激对绒毛高度和隐窝深度的影响,提高肠道淋巴细胞数量和挥发性脂肪酸含量,降低肠道pH,从而缓解断奶应激对肠道环境的影响.     

21日龄断奶对仔猪肠道形态、肠道通透性及肠黏膜屏障的影响

本试验旨在研究21日龄断奶对仔猪肠道形态、肠道通透性及肠黏膜屏障的影响。采用2×3双因子完全随机试验设计,组别(哺乳组、断奶组)和日龄(22、24和28日龄)为2个主效应。选取6窝体况相近的健康大白仔猪,每窝选取6头平均体重为(6.1±0.2)kg的仔猪,随机分为2组,分别为断奶组和哺乳组,每组18头,分别于22、24和28日龄时屠宰,测定其生长性能、肠道形态、肠道通透性及肠黏膜屏障。结果表明:1)28日龄时,断奶组仔猪的末重和平均日增重均极显著低于哺乳组(P0.01)。2)组别和日龄对仔猪的空肠隐窝深度和绒毛高度/隐窝深度、回肠绒毛高度有极显著交互作用(P0.01);断奶组的空肠、回肠隐窝深度极显著高于哺乳组(P0.01),空肠、回肠绒毛高度和绒毛高度/隐窝深度极显著低于哺乳组(P0.01);哺乳组28日龄时的空肠绒毛高度/隐窝深度极显著高于22和24日龄时(P0.01),24日龄时的回肠绒毛高度极显著高于22日龄时(P0.01)。3)组别和日龄对仔猪的空肠黏膜二胺氧化酶(DAO)活性有显著交互作用(P0.05),断奶组的空肠、回肠黏膜DAO活性显著低于哺乳组(P0.05)。4)组别和日龄对仔猪空肠黏膜闭锁蛋白(occludin)的mRNA表达量有极显著交互作用(P0.01);空肠黏膜闭锁小带蛋白1(ZO-1)和哺乳组空肠黏膜occludin的mRNA表达量随着日龄的增加先升高后降低(P0.05);与哺乳组相比,断奶组回肠黏膜ZO-1、occludin和24日龄时空肠黏膜occludin的mRNA表达量显著降低(P0.05);24日龄时回肠黏膜ZO-1的mRNA表达量显著高于22日龄时(P0.05)。5)组别和日龄对仔猪空肠黏膜肿瘤坏死因子α(TNF-α)的mRNA表达量有显著交互作用(P0.05);断奶组24和28日龄时空肠黏膜TNF-α的mRNA表达量显著高于哺乳组(P0.05),空肠黏膜白细胞介素10(IL-10)的mRNA表达量显著低于哺乳组(P0.05)。回肠黏膜白细胞介素1β(IL-1β)的mRNA表达量随着日龄的增加而降低(P0.05)。综上所述,哺乳仔猪22~28日龄时肠道发育趋于成熟,而断奶会破坏仔猪肠道上皮细胞的结构和紧密连接蛋白的mRNA表达,引起肠道绒毛变短和脱落、肠道通透性增加和炎症反应,降低平均日增重。     

发酵豆粕对断奶仔猪生长性能、养分消化率和胃肠道发育的影响

本试验旨在研究发酵豆粕对断奶仔猪生产性能、养分消化率和胃肠道发育的影响.根据胎次、体重相近原则,选择90头26日龄体重为(4.75±0.38)kg的杜枫姜断奶仔猪,分为对照组、试验Ⅰ组(日粮中添加17.5%发酵豆粕)和试验Ⅱ组(日粮中添加35%发酵豆粕),每组3个重复,各重复10头.结果表明:试验Ⅰ、Ⅱ组仔猪日增重分别增加13.90%(P<0.05)、50.55%(P<0.01),料重比分别降低4.21%(JP>0.05)、19.47%(P<0.05).试验Ⅱ组、试验Ⅰ组仔猪腹泻率均极显著(P<0.01)、(P<0.05)低于对照组.试验Ⅰ、Ⅱ组仔猪粗脂肪、粗蛋白质的消化率均显著高于对照组(P<0.05),钙、磷的消化率差异不显著.两试验组仔猪胃内容物pH、胃黏膜和胃壁厚度极显著优于对照组(P<0.01),试验Ⅱ组的肠绒毛高度和绒毛高度/隐窝深度比值显著高于对照组(P<0.05),隐窝深度和肠壁厚度显著降低.     

Stimulation of pig growth performance by porcine growth hormone and growth hormone-releasing factor

The current study was undertaken to determine the effects of human growth hormone-releasing factor [hpGRF-(1-44)-NH2] on growth performance in pigs and whether this response was comparable to exogenous porcine growth hormone (pGH) treatment. Preliminary studies were conducted to determine if GRF increased plasma GH concentration after iv and im injection and the nature of the dose response. Growth hormone-releasing factor stimulated the release of pGH in a dose-dependent fashion, although the individual responses varied widely among pigs. The results from the im study were used to determine the dose of GRF to use for a 30-d growth trial. Thirty-six Yorkshire-Duroc barrows (initial wt 50 kg) were randomly allotted to one of three experimental groups (C = control, GRF and pGH). Pigs were treated daily with 30 micrograms of GRF/kg body weight by im injection in the neck. Pigs treated with pGH were also given 30 micrograms/kg body weight by im injection. Growth rate was increased 10% by pGH vs C pigs (P less than .05). Growth rate was not affected by GRF; however, hot and chilled carcass weights were increased 5% vs C pigs (P less than .05). On an absolute basis, adipose tissue mass was unaffected by pGH or GRF. Carcass lipid (percent of soft-tissue mass) was decreased 13% by GRF (P less than .05) and 18% by pGH (P less than .05). Muscle mass was significantly increased by pGH but not by GRF. There was a trend for feed efficiency to be improved by GRF; however, this was not different from control pigs. In contrast, pGH increased feed efficiency 19% vs control pigs (P less than .05). Chronic administration of GRF increased anterior pituitary weight but did not affect pituitary GH content or concentration. When blood was taken 3 h post-injection, both GRF- and pGH-treated pigs had lower blood-urea nitrogen concentrations. Serum glucose was significantly elevated by both GRF and pGH treatment. This was associated with an elevation in serum insulin. These results indicate that increasing the GH concentration in blood by either exogenous GH or GRF enhances growth performance. The effects of pGH were more marked than for GRF. Further studies are needed to determine the optimal dose of GRF to administer in growth trials and the appropriate pattern of GRF administration in order to determine whether GRF will enhance pig growth performance to the extent that exogenous pGH does.     

Stimulation of swine growth by porcine growth hormone

Highly purified porcine growth hormone (pGH; USDA-B1) was administered by im injection (22 micrograms X kg body weight-1 X d-1) to rapidly growing Yorkshire barrows for 30 d. Growth hormone significantly increased growth rate (10%), feed efficiency (4%), cartilage growth and muscle mass. However, pGH did not affect carcass adipose tissue mass. Intramuscular lipid content of the longissimus was increased 50% by pGH administration. Plasma pGH concentration was elevated (7- to 11-fold) for 3 to 5 h post-injection. Chronic administration of pGH depressed pituitary GH content and concentration approximately 45%. No GH antibodies were detected in the plasma of GH-treated swine. Plasma somatomedin-C concentration was increased 55% by GH treatment 3 h post-injection. Plasma glucose and insulin concentrations were both significantly increased in GH-treated swine, suggesting that the animals had developed a state of insulin resistance. Plasma-free fatty acid concentration tended to be higher in GH-treated animals. Treatment of swine with pGH significantly decreased plasma blood urea nitrogen. Assessment of animal health during the trial and postmortem indicated that pGH administration did not have any adverse effects. In summary, treatment of young, rapidly growing swine with pGH stimulated growth performance without affecting animal health or inducing the production of GH antibodies.     

生长调节剂对坪用多年生黑麦草生长特性的影响

通过盆栽试验,研究了不同浓度的4种生长调节剂对多年生黑麦草(Lolium perenne)株高、叶长、叶宽、分蘖数及地上部植株鲜、干质量的影响。结果表明,多效唑和矮必施对多年生黑麦草株高、叶长及地上部植株鲜、干质量的抑制作用显著,但浓度过高会对草坪造成较大损伤。因此,建议选用浓度为200 mg·L-1的多效唑和375 mg·L-1的矮必施作为多年生黑麦草的化学修剪药剂。     

生长调节剂对紫花苜蓿微扦插试管苗生长的影响

以紫花苜蓿品种甘农3号(G3)、和田(HT)、陇东(LD)为材料,研究不同种类和不同浓度的生长调节剂吲哚丁酸(IBA)、萘乙酸(NAA)、生根粉(ABT)对苜蓿微扦插试管苗生长的影响。结果表明,0.2mg/L NAA处理下的G3紫花苜蓿试管苗生根率达100%,且具有较高的生根数(8),最大根长(17.5cm),株高和叶片数也显著高于对照和其他处理(P0.05);0.1mg/L NAA处理下的和田紫花苜蓿试管苗的根系生长状况明显优于其他处理,生根率为100%,具有较高的生根数(7),最大根长(29.6cm),株高和叶片数也显著高于对照和其他处理(P0.05);0.2mg/L NAA处理下的陇东紫花苜蓿试管苗的根系生长情况明显优于其他处理,生根率100%,并具有较高的生根数(7),最大根长(10.2cm),株高和叶片数也显著高于对照和其他处理(P0.05)。因此,在设置的浓度梯度下,甘农3号和陇东紫花苜蓿微扦插试管苗生长的最适生长调节剂及其浓度是0.2mg/L NAA,适于和田紫花苜蓿的是0.1mg/L NAA。     

Use of growth hormone response to growth hormone-releasing hormone to determine growth potential in beef heifers.

The response of GH to GHRH at weaning is known to predict postweaning growth and body composition in beef bulls. The objective of this study was to determine whether GH response to a challenge of GHRH and plasma IGF-I can predict growth rate and body composition in the beef heifer. Growth hormone response to a challenge with two doses of GHRH was measured in 67 Angus heifers averaging 225 d of age (SD = 21) and 217 kg BW (SD = 32). Blood samples were collected at 0 and 10 min relative to an initial "clearance dose" (4.5 micrograms GHRH/100 kg BW) and again, 3 h later, relative to a challenge dose (1.5 or 4.5 micrograms GHRH/100 kg BW). Each animal received each of the two challenge doses, which were randomly assigned across 2 d of blood collection. Serum GH concentration was measured by RIA. Plasma was collected every 28 d during a 140-d growth test and assayed for IGF-I by RIA. Body weight was measured every 28 d and hip height was measured at weaning and at the end of a 140-d growth test. Average daily gain was calculated on d 140 of the growth test and body composition measurements were estimated by ultrasound 2 wk after completion of the growth test. Responses to the two GHRH challenges were dose-dependent (P < 0.05). Average daily gain tended to be related to GH response to the 1.5 micrograms GHRH/100 kg BW dose (R2 = 0.05; P = 0.06), but no relationship was observed at the 4.5 micrograms GHRH/100 kg BW dose (R2 = 0.00; P = 0.93). An inverse relationship (R2 = 0.06; P = 0.02) was observed between response to the 1.5 micrograms GHRH/100 kg BW dose and intramuscular fat percentage. Mean plasma IGF-I concentration was positively associated with ADG (R2 = 0.06; P < 0.01). Growth hormone response to GHRH is modestly related to body composition but not to ADG in weanling beef heifers and likely has limited use in evaluation of growth performance in replacement beef heifers.     

Plasma growth hormone concentrations during growth in turkeys

1. The concentrations of circulating GH were low in 1‐week‐old birds (male plasma pool 30 ng/ml, female 32 ng/ml), reached a maximum at 7 weeks in male birds (142 ± 26 SEM ng/ml) or 4 weeks in females (185 ± 32 ng/ml) and then decreased to 17.3 ± 2–8 ng/ml in males and 8?7 ± 0–6 ng/ml in females at 17 weeks.

2. Significant inverse correlations between GH concentration and age or body weight were found (male, r = —0–693), female, r = —0–623).

3. In males, but not females, the weekly increase in body weight was correlated with the plasma GH concentration (r = 0–291).     

植物生长调节剂处理对金桔幼果生长的影响

为确定最适用于金桔幼果生长的植物生长调节剂种类及浓度,在金桔第二批花期后幼果膨大期,分别用4种浓度梯度的赤霉素（GA3）、6-苄氨基嘌呤（6-BA）和芸苔素（BR）对金桔果树进行喷施试验,结果表明：各处理果实的横径增加2.47%-12.21%,纵径增加6.33%-16.33%,可溶性蛋白含量增加1.07-1.87倍,过氧化物酶活性提高1.21-5.16倍,有9个处理可溶性糖含量增加,7个处理的还原糖含量提高,9个处理的果形指数增大,各处理对幼果果柄长度无显著增大。对处理后的8个相关品质指标进行主成分分析,结果表明T7(60 mg/L 6-BA)处理更有利于金桔幼果的生长。     

Immunolocalization of basic fibroblast growth factor in porcine epiphyseal growth plate

Recent evidence clearly indicates that basic fibroblast growth factor (bFGF) signal transduction is essential for normal skeletal development. Here, we report that bFGF and its receptor are specifically localized in the terminal hypertrophic chondrocytes of the porcine epiphyseal growth plate, the tissue responsible for longitudinal bone growth. Similar observations were obtained with the chondrocytes immediately adjacent to resorbing blood vessels in the secondary center of ossification of the epiphysis. These results are consistent with a recent proposal that bFGF functions in coupling osteogenesis with chondrogenesis by attracting the vascular invasion of cartilage from adjacent trabecular bone.     

Effect of compensatory growth on regulation of growth and lactation: response of dairy heifers to a stair-step growth pattern

The primary objective of this study was to improve the productive efficiency of growth via optimal use of both high fiber-low quality and high energy-high protein feeds in diets for growing dairy cattle. Twenty Holstein heifers were randomly assigned to either a control or treatment group. The control diet met the National Research Council (NRC) requirement for .45 kg/d gain, with heifers calving at 24 to 26 mo of age. The test groups were fed according to a 5-2-5-2 mo schedule in which the nutrient density was alternately 15% below or 40% above the NRC requirement. Results showed that the heifers on the test dietary regimen (compensatory growth) gained more and consumed less, resulting in significantly improved efficiency of growth (body gain/dry matter intake X 100), energy (body gain X 1,000/metabolizable energy (ME) intake) and protein utilization (body gain/protein intake X 100) in comparison to control animals (13.0 vs 7.3%; 57.9 vs 32.6 g/Mcal ME; 96.5 vs 54.2%, respectively). Marked changes in average concentration of urea-N, glucose, triglycerides, cholesterol and lecithin cholesterol acyltransferase activity in blood were seen for test heifers during the stair-step growth phase (i.e., alternating maintenance and compensatory). Evidence from this experiment suggests that the phased growth (stair-step) system offers a simple, practical and cost-effective method for raising dairy heifers.     

AA肉仔鸡潜在生长性能预测及其生长曲线拟合的研究

本文采用Gompertz模型对处于不同日粮代谢能水平下0～8周龄AA肉鸡的生长曲线进行分析和非线性曲线拟合研究。结果显示:1周龄前公鸡、母鸡均生长缓慢,1周龄后生长速率开始增加,5周龄左右达到增重高峰,对公鸡而言,7周龄后日粮中14.23、13.39MJ/kg和11.72MJ/kg代谢能组生长速率均较7周前变缓。母鸡与公鸡具有相似的生长趋势,但1～2周龄时母鸡比公鸡有较大的生长速率,表现在母鸡体重比公鸡体重较大(P0.05),3周龄后同一水平下母鸡的生长速率显著慢于公鸡生长速率(P0.05)。Gompertz方程能较好地拟合公鸡与母鸡的生长曲线,其中13.39MJ/kg代谢能组的极限体重最高,拟合度分别达到99.9%、99.6%,拟合效果最好。采用Gompertz模型对0～8周龄公鸡与母鸡生长曲线拟合的方程分别为:BWt=5262.19×e{-e[-0.044×(t-36.093)]}和BWt=4823.04×e{-e[-0.045×(t-34.960)]}。该模型可用于肉仔鸡潜在生长性能的预测。