益生菌对乳鸽生长性能、血清生化指标及肠道功能的影响

本试验旨在研究丁酸梭菌和乳酸菌对乳鸽生长性能、血清生化指标、小肠消化酶活性及肠道形态的影响。选取相同繁殖周期的种鸽84对和同日出雏的1日龄乳鸽252只,每对种鸽哺育3只乳鸽,随机分成7组,每组6个重复,每个重复2对种鸽和6只乳鸽。对照组(A组)饲喂基础饲粮,抗生素组(B组)在基础饲粮中添加150 mg/kg金霉素,试验组(C、D、E、F、G组)分别在基础饲粮中添加5×107、1×108、2×108CFU/kg丁酸梭菌,5×109CFU/kg乳酸菌和5×109CFU/kg乳酸菌+1×108CFU/kg丁酸梭菌。试验期28 d。结果表明:1) G组乳鸽15～28日龄、1～28日龄时的平均日增重及28日龄时的体重显著高于对照组(P0.05),与抗生素组相比无显著差异(P0.05)。2)与对照组和抗生素组相比,除E组乳鸽的血清总蛋白(TP)和总胆固醇(TC)含量外,丁酸梭菌和乳酸菌显著提高血清TP和白蛋白(ALB)含量(P0.05),显著降低血清TC含量(P0.05); G组的血清甘油三酯(TG)和尿素氮(UN)含量显著低于对照组(P0.05)。3)与对照组和抗生素组相比,G组乳鸽的十二指肠内容物中胰蛋白酶、脂肪酶、淀粉酶活性和C组的十二指肠内容物中淀粉酶活性显著升高(P0.05)。4)与对照组相比,G组乳鸽的十二指肠、空肠、回肠绒毛高度及绒毛高度/隐窝深度(V/C)显著升高,隐窝深度显著降低(P0.05); D和G组的十二指肠黏膜厚度显著升高(P0.05); C和D组的空肠、回肠隐窝深度显著降低(P0.05)。与抗生素组相比,G组的十二指肠黏膜厚度及空肠、回肠V/C显著升高(P0.05)。综上所述,在种鸽饲粮中添加丁酸梭菌和乳酸菌能促进乳鸽生长,改善血清生化指标,提高小肠消化酶活性,且对乳鸽的肠道形态有很好的改善作用。在本试验条件下,丁酸梭菌和乳酸菌复合添加的效果优于单独添加,且单独添加以D组的效果为最好。     

丁酸梭菌和乳酸菌对青年鸽免疫指标、血清抗氧化指标及肠道功能的影响

本试验旨在研究丁酸梭菌和乳酸菌对青年鸽免疫性能、血清抗氧化指标、小肠消化酶活性和肠道形态的影响。选取80日龄左右的雌性青年鸽384只,将其随机分成4组,每组6个重复,每个重复16只。其中A组饲喂基础日粮,B、C和D组分别在基础日粮中添加1×10~8 CFU/kg丁酸梭菌、5×10~9 CFU/kg乳酸菌和5×10~9 CFU/kg乳酸菌+1×10~8 CFU/kg丁酸梭菌。预试期7 d,试验期28 d。结果表明:①与A组相比,B、C、D组脾脏指数和法氏囊指数均有所提高,但差异不显著(P0.05)。②与A组相比,B、C、D组青年鸽血清超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、过氧化氢酶(CAT)活性及总抗氧能力(T-AOC)均显著提高(P0.05),丙二醛(MDA)含量显著降低(P0.05);与B、C组相比,D组血清T-AOC及CAT、GSH-Px活性均显著提高(P0.05)。③与A组相比,B、D组十二指肠内胰蛋白酶活性显著提高(P0.05),D组脂肪酶活性显著提高(P0.05)。④与A组相比,D组十二指肠隐窝深度显著降低(P0.05),B组十二指肠及D组十二指肠、回肠绒毛高度/隐窝深度比值均显著提高(P0.05)。综上所述,在日粮中添加丁酸梭菌和乳酸菌有利于改善青年鸽肠道形态,提高小肠消化酶活性及血清抗氧化能力,从而增强青年鸽的免疫力。     

壳寡糖和丁酸梭菌对肉仔鸡生长性能、血清生化指标及内脏器官相对重的影响

试验旨在研究壳寡糖和丁酸梭菌对AA肉仔鸡生长性能、血清生化指标以及内脏器官相对重的影响。采用2×2双因子试验设计,选取360只1日龄健康AA肉鸡公雏,随机分成4组,每组6个重复,每个重复15只。对照组饲喂基础饲粮,壳寡糖组饲喂基础饲粮+150 mg/kg壳寡糖,丁酸梭菌组饲喂基础饲粮+5×10~8cfu/kg丁酸梭菌,复合组饲喂基础饲粮+150 mg/kg壳寡糖+5×10~8cfu/kg丁酸梭菌。试验期为42 d。结果表明:饲粮单独添加壳寡糖或丁酸梭菌或壳寡糖和丁酸梭菌联合使用均显著降低了1～21日龄肉仔鸡的料重比(P0.05);试验组肉仔鸡血清中碱性磷酸酶含量极显著低于对照组(P0.01);与对照组相比,饲粮单独添加壳寡糖或丁酸梭菌均显著降低了肉仔鸡空肠相对重(P0.05)。综上所述,饲粮添加壳寡糖或丁酸梭菌能够促进肉仔鸡的生长发育,但二者联合使用效果不优于二者单独使用效果。     

日粮添加丁酸梭菌及其复合菌剂对蛋鸡夏季生产性能的影响

试验旨在探究日粮添加丁酸梭菌及其复合菌剂对蛋鸡夏季生产性能、蛋品质和血清生化指标的影响。随机选用380日龄京粉2号蛋鸡360只,随机分成4组,每组6个重复,每个重复15只鸡。对照组饲喂基础日粮,3个试验组分别在基础日粮中添加1×10~5CFU/g丁酸梭菌(活菌数1×10~9CFU/g)、2×10~6CFU/g复合益生菌A(由丁酸梭菌和凝结芽孢杆菌组成,活菌数分别为4×10~8 CFU/g和1.96×10~(10) CFU/g)、5×10~6 CFU/g复合益生菌B(由丁酸梭菌和地衣芽孢杆菌组成,活菌数分别为1×10~8CFU/g和9.9×10~9CFU/g)。预试期1周,正试期12周。结果表明:与对照组相比,丁酸梭菌组和复合益生菌A组的料蛋比分别降低6.7%和6.3%(P0.05),产蛋率提高3.0%和2.9%(P0.05);与对照组相比,复合益生菌A组的蛋白高度、蛋黄重和蛋黄比例分别提高7.1%、6.3%和3.6%(P0.05),复合益生菌B组的蛋黄重和蛋黄比例提高3.9%和3.8%(P0.05),丁酸梭菌组蛋白高度和哈氏单位提高16.8%和12.2%(P0.05),试验56 d采集鸡蛋保存14 d之后,丁酸梭菌组蛋白高度提高18.5%(P0.05),复合益生菌A组的哈氏单位和蛋壳强度分别提高21.3%和15.2%(P0.05);复合益生菌B组血清总蛋白和白蛋白分别降低13.9%和10.9%(P0.05)。由此可见,日粮添加丁酸梭菌及其复合菌剂能有效缓解夏季高温对产蛋鸡生产性能和蛋品质造成的负面影响,并延长鸡蛋存放时间,改善血清生化指标。     

益生菌对青年鸽生长、免疫和抗氧化性能及繁殖相关基因表达的影响

本试验旨在研究丁酸梭菌和乳酸菌对青年鸽生长性能、血清免疫指标和生化指标、肝脏抗氧化指标及与繁殖相关基因表达的影响。选取80日龄左右的雌性青年鸽384只,将其随机分成4组,每组6个重复,每个重复16只。其中A组饲喂基础饲粮,B、C和D组分别在基础饲粮中添加1×10^8CFU/kg丁酸梭菌、5×10^9CFU/kg乳酸菌和5×10^9CFU/kg乳酸菌+1×10^8CFU/kg丁酸梭菌。预试期7d,试验期28d。结果表明:1)与A组相比,B、C和D组青年鸽的平均日增重分别提高了22.0%、32.0%和22.0%,但差异不显著(P>0.05)。2)与A组相比,C和D组青年鸽血清中的免疫球蛋白M(IgM)含量显著提高(P<0.05),各组间血清中免疫球蛋白A(IgA)和免疫球蛋白G(IgG)含量差异不显著(P>0.05)。3)与A组相比,D组青年鸽血清中的总胆固醇(TC)含量显著降低(P<0.05),B、C和D组血清中的甘油三酯(TG)含量均显著下降(P<0.05)。4)与A组相比,B、C和D组青年鸽肝脏中的过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH Px)活性均显著提高(P<0.05),C和D组青年鸽肝脏中的超氧化物歧化酶(SOD)活性和总抗氧化能力(T AOC)显著提高(P<0.05),D组青年鸽肝脏中的丙二醛(MDA)含量显著降低(P<0.05)。5)与A组相比,C和D组青年鸽卵巢中的骨形态发生蛋白15(BMP15)、促卵泡素受体(FSHR)基因表达水平显著提高(P<0.05)。综上所述,在饲粮中添加丁酸梭菌和乳酸菌能够提高青年鸽肝脏抗氧化功能并增强机体免疫力,促进新陈代谢,从而提高青年鸽的生长性能,对青年鸽的繁殖潜力也起到促进作用。     

丁酸梭菌和地衣芽孢杆菌对北京鸭生长性能、血清生化和免疫指标及免疫器官指数的影响

本试验旨在研究饲粮中添加丁酸梭菌和地衣芽孢杆菌对北京鸭生长性能、血清生化和免疫指标及免疫器官指数的影响。选取1日龄健康北京鸭300只,随机分成5组,每组6个重复,每个重复10只鸭。对照组(试验Ⅰ组)饲喂基础饲粮,试验组分别在基础饲粮中添加40 mg/kg杆菌肽锌(试验Ⅱ组)、5×108CFU/kg丁酸梭菌(试验Ⅲ组)、1×109CFU/kg地衣芽孢杆菌(试验Ⅳ组)和5×108CFU/kg丁酸梭菌+1×109CFU/kg地衣芽孢杆菌(试验Ⅴ组)。试验期21 d。结果表明:1)试验Ⅱ、Ⅲ、Ⅳ、Ⅴ组的平均日增重均显著高于对照组(P0.05)。各组之间的平均日采食量和料重比差异不显著(P0.05)。2)试验Ⅴ组的血清中免疫球蛋白A、免疫球蛋白G、补体3、补体4含量显著高于对照组(P0.05)。各组之间的血清中总蛋白、白蛋白、尿素氮含量差异不显著(P 0.05)。3)试验Ⅴ组的胸腺指数、脾脏指数显著高于对照组(P 0.05)。各组之间的法氏囊指数差异不显著(P 0.05)。由此可见,饲粮中添加丁酸梭菌与地衣芽孢杆菌复合菌可以有效改善北京鸭的生长性能和免疫指标。     

丁酸梭菌对产蛋后期汶上芦花鸡生产性能和蛋品质的影响

本试验旨在研究丁酸梭菌对汶上芦花鸡产蛋后期生产性能和蛋品质的影响。选用120只体重相近的330日龄汶上芦花鸡,分为5组,每组4个重复,每个重复6只鸡,自由采食和饮水。对照组只饲喂基础日粮,复合益生菌组在基础日粮中添加复合益生菌;3个水平的丁酸梭菌组(CB组)在基础日粮中分别添加1×10~7CFU/kg、1×10~8CFU/kg、1×10~9CFU/kg丁酸梭菌。试验期8周,比较分析生产性能和蛋品质。结果显示,在试验开始的第2周,10~8CB组的蛋黄指数显著高于对照组(P<0.05);在试验开始的第6周,丁酸梭菌3个处理组蛋壳指数均显著高于对照组(P<0.05),10~9CB组蛋壳强度与对照组相比显著增加;在试验开始的第8周,10~7CB组哈氏单位和蛋白高度以及蛋黄颜色均显著高于对照组(P<0.05),但丁酸梭菌对产蛋后期汶上芦花鸡产蛋率、平均蛋重、蛋壳厚度及蛋壳重量无显著影响(P>0.05)。综上结果,饲粮中添加丁酸梭菌有助于提高产蛋后期汶上芦花鸡鸡蛋品质,提高蛋禽经济效益。     

丁酸梭菌和乳酸菌对青年鸽免疫指标、血清抗氧化指标及肠道功能的影响

本试验旨在研究丁酸梭菌和乳酸菌对青年鸽免疫性能、血清抗氧化指标、小肠消化酶活性和肠道形态的影响。选取80日龄左右的雌性青年鸽384只,将其随机分成4组,每组6个重复,每个重复16只。其中A组饲喂基础日粮,B、C和D组分别在基础日粮中添加1×10⁸ CFU/kg丁酸梭菌、5×10⁹ CFU/kg乳酸菌和5×10⁹ CFU/kg乳酸菌+1×10⁸ CFU/kg丁酸梭菌。预试期7 d,试验期28 d。结果表明：①与A组相比,B、C、D组脾脏指数和法氏囊指数均有所提高,但差异不显著（P>0.05）。②与A组相比,B、C、D组青年鸽血清超氧化物歧化酶（SOD）、谷胱甘肽过氧化物酶（GSH-Px）、过氧化氢酶（CAT）活性及总抗氧能力（T-AOC）均显著提高（P<0.05）,丙二醛（MDA）含量显著降低（P<0.05）;与B、C组相比,D组血清T-AOC及CAT、GSH-Px活性均显著提高（P<0.05）。③与A组相比,B、D组十二指肠内胰蛋白酶活性显著提高（P<0.05）,D组脂肪酶活性显著提高（P<0.05）。④与A组相比,D组十二指肠隐窝深度显著降低（P<0.05）,B组十二指肠及D组十二指肠、回肠绒毛高度/隐窝深度比值均显著提高（P<0.05）。综上所述,在日粮中添加丁酸梭菌和乳酸菌有利于改善青年鸽肠道形态,提高小肠消化酶活性及血清抗氧化能力,从而增强青年鸽的免疫力。     

日粮中添加丁酸梭菌对断奶仔猪生长性能、抗氧化能力和免疫功能的影响

旨在研究丁酸梭菌对断奶仔猪生长性能、抗氧化能力和免疫功能的影响。选用180头初始体重为(8.07±0.84)kg的杜×长×大三元杂交仔猪,公母各半,按照随机区组分为5组,每组6个重复,每个重复6头猪。试验分为阴性对照组,饲喂不含抗生素的基础日粮;抗生素组,基础日粮中添加75mg·kg~(-1)金霉素;丁酸梭菌处理组,日粮中有效活菌数分别达到1.0×10~8、1.0×10~9、5.0×10~9 CFU·kg~(-1)。试验期为28d。于试验第0、14、28天对仔猪进行称重。从试验期开始,观察并记录仔猪每日腹泻状况。试验第28天,各处理每重复选取1头健康仔猪进行采血,分别依据商品试剂盒的说明测定血清中免疫指标和抗氧化指标。结果表明:1)1~14d、15~28d以及1~28d日粮中添加不同浓度的丁酸梭菌对断奶仔猪平均日增重、平均日采食量和耗料增重比均无显著影响(P0.05);2)1~14d和1~28d不同添加剂量丁酸梭菌处理组的腹泻率随添加剂量的上升呈线性显著增加(P0.05),15~28d和1~28d各处理之间断奶仔猪粪便评分差异显著(P0.05);3)日粮中添加5.0×10~9 CFU·kg~(-1)的丁酸梭菌可以显著提高断奶仔猪血清中谷胱甘肽过氧化物酶的含量和总抗氧化能力(P0.05)。与基础日粮组相比,日粮中添加1×10~9 CFU·kg~(-1)和5.0×10~9 CFU·kg~(-1)的丁酸梭菌均显著提高断奶仔猪血清中总超氧化物歧化酶的含量,并且断奶仔猪血清中的总超氧化物歧化酶水平随丁酸梭菌添加量的增加呈线性显著提高(P0.05)。相比于基础日粮组,丁酸梭菌处理组间断奶仔猪血清中丙二醛含量无显著差异(P0.05);4)各处理组随着丁酸梭菌添加量的增加仔猪血清免疫球蛋白G含量有上升的趋势(P0.10)。与基础日粮组相比,日粮中添加5.0×109 CFU·kg~(-1)的丁酸梭菌可以显著降低仔猪血清中肿瘤坏死因子-α(P0.05)和白细胞介素-6(P0.01)的含量,显著提高血清中白细胞介素-4含量(P0.01),并且断奶仔猪血清中的白细胞介素-4含量随丁酸梭菌添加量的增加呈线性显著提高(P0.05)。各处理组仔猪血清中白细胞介素-1β含量无显著差异(P0.05)。结果表明,日粮中添加1×10~9~5.0×10~9 CFU·kg~(-1)丁酸梭菌可以提高断奶仔猪抗氧化能力和免疫功能,有助于提高仔猪断奶阶段的健康水平和抗应激能力。     

甘露寡糖-丁酸梭菌对14日龄肉鸡粪便菌群的影响

试验旨在探究丁酸梭菌、甘露寡糖及两者联合添加对肉鸡肠道菌群结构的影响。选取400只1日龄健康、体重相近科宝肉鸡随机分为4组,每组5个重复,每个重复20只鸡。对照组肉鸡饲喂基础日粮,丁酸梭菌组在基础日粮中添加2×10⁹ CFU丁酸梭菌,甘露寡糖组在基础日粮中添加0.2%甘露寡糖,联合添加组在基础日粮中添加2×10⁹ CFU丁酸梭菌+0.2%甘露寡糖。试验期14 d。与对照组相比,各试验组厚壁菌门(Firmicutes)细菌含量均有所减少,变形杆菌门(Proteobacteria)含量增加,联合添加组和丁酸梭菌组拟杆菌门(Bacteroidetes)含量分别增加13.29%、2.37%。丁酸梭菌组放线菌门(Actinobacteria)高于对照组2.89%。与对照组相比,各试验组肉鸡粪便杆菌纲(Bacilli)细菌含量均减少,γ变形菌纲(Gammapro-teobacteria)、梭状芽孢杆菌纲(Clostridiales)含量增多。与对照组相比,试验组肉鸡粪便乳杆菌目(Lactobacillales)含量均有所减少,肠杆菌目(Enterbact...     

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。     

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。     

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).     

银羽王鸽早期生长规律及生长曲线拟合的分析

试验随机选取银羽王鸽120只,测定从初生到4周龄的银羽王鸽早期生长发育情况,并对其进行了分析。运用Logistic、Gompertz、von Bertalanffy 3种生长曲线模型拟合其生长曲线,并对拟合结果进行比较分析。结果发现,von Bertalanffy模型能更好地拟合银羽王鸽的生长曲线(R2=0.9996)。     

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。     

蛋氨酸对动物生长发育及毛发生长调控作用的研究进展

蛋氨酸(Met)是动物生长必需氨基酸中唯一含硫氨基酸,其可参与机体内众多代谢途径,为动物提供甲基,合成动物生长所需要的蛋白质和生物活性物质,是动物生长和毛发生长的第一限制性氨基酸。日粮中必须添加适量的蛋氨酸才能满足动物生长需要,对毛皮动物,蛋氨酸还会影响毛发的生长和品质,所以蛋氨酸又被称为"生命性氨基酸"。本文综述了蛋氨酸在动物生长发育及毛发生长中的调控作用,以期为蛋氨酸在畜牧生产中的科学应用提供参考。     

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。