牦牛放牧率对小嵩草高寒草甸不同植物类群地上生物量生产率的影响

2年的牦牛放牧试验表明:除不同植物本身的生理特性外,降水和地温是影响小嵩草高寒草甸两季草场不同植物类群地上生物量绝对生长率的关键因素。小嵩草高寒草甸两季草场地上总生物量的绝对生长率1999年在7月份最大;1998年,冷季草场各放牧处理的绝对生长率在8月份达到最大,暖季草场的对照组和轻牧组在7月份最大,中牧组和重牧组在8月份最大。不同植物类群地上生物量生长率的变化不尽相同。1998年,冷季草场禾草和莎草地上生物量的绝对生长率8月份达到最大,暖季草场禾草和莎草地上生物量的绝对生长率7月份达到最大,且9月份出现了营养的再次积累;1999年,冷季草场禾草地上生物量的绝对生长率在6月份和8月份出现了两个峰值,暖季草场禾草地生物量的绝对生长率在7月份达到最大。对杂草类而言,1998年冷季草场的绝对生长率6月份最大,暖季草场重牧组的绝对生长率8月份达到最大,其他各处理7月份达到最大;1999年重牧组杂草的绝对生长率在6月份达到最大,其他各处理杂草在8月份达到最大。     

饲料粉碎粒度和调质温度对肉鸡养分消化率及生长性能的影响

饲料制粒可以提高采食量和缩短采食时间,以提高肉鸡生长性能和饲料转化率.而原料的粉碎和调质是制粒过程中非常重要的环节,不仅直接影响到饲料的营养价值和肉鸡的消化吸收,还会影响加工成本和产品质量.粉碎粒度过大会导致混合不均匀、颗粒品质欠佳等不利影响,并且对动物的采食及采食后的物理性消化产生影响,粒度过小则会对动物健康产生不利影响.调质过程主要是使饲料受到水热作用,使其蛋白质变性、淀粉糊化等,调质温度是调质环节的关键参数,温度的高低对蛋白质变性及淀粉糊化程度有直接影响,从而间接影响到动物的生长性能和养分消化利用率.同时,调质温度过高会导致饲料中添加的酶制剂及维生素等严重失活,反而会降低饲料的营养价值.本文综述了肉鸡饲料粉碎粒度和调质温度的研究进展,阐述了粉碎粒度、调质温度与肉鸡生长性能和养分消化率的重要关系.     

Effects of the prebiotic mannan‐oligosaccharide on feed deprived zebrafish: Growth and reproduction

This study was designed to investigate whether the prebiotic mannan‐oligosaccharides (MOS) can reduce the deleterious impacts of feed deprivation on growth and reproduction in zebrafish. In the growth performance experiment, juvenile fish were distributed in the following four treatments: normal‐control (NC), starved‐control (SC), normal‐prebiotic (NP) and starved‐prebiotic (SP). After 8 weeks, NP and SC fish showed the highest and lowest growth patterns, respectively among treatments. Standard length, specific growth rate and feed conversion ratio did not differ significantly between NC and SP treatments. Autochthonous lactic acid bacteria (LAB) were significantly higher in NP and SP than the NC and SP treatments. Feed restriction resulted in significantly lower concentrations of thyroxine. In the reproductive performance experiment, additional juveniles were fed as in the growth experiment. Crossing in the final week of the experiment resulted in successful spawning in only NP fish, which showed mature sperm and oocytes in histological examinations. The number of spermatozoa was significantly lower in the fish that experienced feed restriction; however, the oocytes of SP females were at the same maturation level to that observed in NC females. Sex‐steroids changed after both starvation and MOS supplementation where NC and SP showed no differences in the levels of testosterone and female's 17β‐estradiol. These results indicate that MOS supplemented diet reduced some side effects of feed deprivation (final weight and length, SGR, FCR and levels of LAB and T3), and suggest that supplementation of the diet with MOS may ameliorate some of the negative effects of feed deprivation in zebrafish.     

合浦珠母贝幼贝生长性状的遗传参数估计

以广东徐闻和海南三亚2个地理群体合浦珠母贝(Pinctada fucata)为亲本, 采用人工授精方法构建了33个全同胞家系。在162日龄时从每个家系随机抽取50个个体, 共1 650个, 测量其壳长、壳高、壳宽和体质量4个生长性状, 利用动物模型对4个性状进行遗传参数分析。结果表明, 合浦珠母贝4个生长性状的总平均值分别为(16.28 ± 4.46) mm、(14.85 ± 4.39) mm、(4.58 ± 1.52) mm、(0.66 ± 0.67) g。4个性状的遗传力分别为0.202 ± 0.020、0.203 ± 0.020、0.200 ± 0.021和0.204 ± 0.020, 均属中等遗传力, 因此可以用选择育种进行遗传改良。4个性状间表型相关系数和遗传相关系数的范围分别为0.667~0.698和0.685~0.959, 其中壳长、壳高和壳宽之间的遗传相关系数均低于0.7, 与表型相关一致, 而三者与体重间的遗传相关系数较高(0.868~0.959), 其中壳宽与体质量间的遗传相关系数最高(0.959)。本研究中合浦珠母贝的4个性状为中等遗传力, 并可通过对壳宽的选育来改良体质量性状。上述结果为进一步开展合浦珠母贝选择育种研究奠定了基础。

     

不同增殖方式来源的绿潮藻浒苔藻体生长及光合生理特性差异

为了探讨原位状态下不同增殖方式得到的绿潮藻浒苔生物体的差异,通过原位围隔实验,分别获取漂浮浒苔释放的孢子萌发形成的藻体(ST)和浒苔自身营养增殖得到的藻体(VT),通过比较这两种浒苔的生长、光合作用和荧光参数的不同,来估测其光合生理特性的差异。结果表明,ST的生长速率比VT显著高出61.27%,并且ST的最大光合作用速率(Pmax)、光合效率(α)和光合活性(P/R)比VT分别显著高出25.33%、14.93%和134.69%,而呼吸作用速率和光补偿点比VT显著低了45.7%和52.2%,这表明ST与VT相比具有更大的生长优势。另外,VT的相对电子传递速率(rETR)显著高于ST,在高光下尤为显著,并且VT在高光下具有更高的非光化学猝灭(NPQ)能力,这说明浒苔通过自身营养增殖产生的藻体对高光的适应能力比其由孢子萌发形成的藻体更强。     

小球藻醇提物对瓦氏黄颡鱼幼鱼生长性能、体成分、消化酶活性及血清生化和抗氧化指标的影响

本试验旨在研究饲料中添加不同水平的小球藻醇提物(EEFCV)对瓦氏黄颡鱼幼鱼生长性能、体成分、消化酶活性及血清生化和抗氧化指标的影响。试验选用体质量约1.85 g的瓦氏黄颡鱼苗540尾,随机分为6个组,每组3个重复,每个重复30尾鱼。各组分别投喂添加0(T0组)、0.25%(T1组)、0.50%(T2组)、1.00%(T3组)、1.50%(T4组)和2.50%(T5组)EEFCV的6种等氮等脂试验饲料,饲养周期为56 d。结果表明:1)T4和T5组的末均重、增重率和特定生长率均显著高于T0组(P<0.05),T4和T5组的饲料系数均显著低于T0组(P<0.05)。各组的存活率、肥满度、脏体比和肝体比无显著差异(P>0.05)。2)各组的粗蛋白质和粗灰分含量无显著差异(P>0.05)。T5组的粗脂肪含量显著高于T0组(P<0.05),T5组的水分含量显著低于T0组(P<0.05)。3)各组的胃、肠和肝脏的蛋白酶、淀粉酶和脂肪酶活性均无显著差异(P>0.05)。4)各组的血清谷丙转氨酶、谷草转氨酶活性及胆固醇、甘油三脂、尿素氮、葡萄糖和总蛋白含量均无显著差异(P>0.05)。T1、T3和T4组的血清谷草转氨酶活性显著高于T0组(P<0.05)。5)T4组的血清丙二醛含量显著低于T0组(P<0.05),T3、T4和T5组的血清超氧化物歧化酶活性显著高于T0组(P<0.05)。各组的血清总抗氧化能力无显著差异(P>0.05)。由此可见,饲料中添加EEFCV对黄颡鱼幼鱼生长性能和抗氧化能力有促进作用,以增重率、特定生长率和饲料系数作为主要评估指标,饲料中添加1.50%的EEFCV应用效果较佳。     

颗粒日粮中添加柠条对滩羊生长性能、血液生化指标、瘤胃发酵及羊肉品质的影响

[目的]研究颗粒日粮中添加柠条对滩羊生长性能、血液生化指标、瘤胃发酵及羊肉品质的影响。[方法]选择体重相近的健康去势滩羊20只,随机分成两组,每组10只;对照组饲喂含有10%菊花粕的颗粒日粮,试验组饲喂含有6%柠条和4%菊花粕的颗粒日粮;开展周期为50天的育肥试验,测定滩羊的生长性能指标;育肥试验结束后,测定滩羊血液生化指标;屠宰后测定滩羊的屠宰性能指标,并取瘤胃液测定瘤胃发酵指标;取背腰最长肌,测定粗脂肪、粗蛋白、氨基酸含量以及脂肪酸组成。[结果]试验组和对照组滩羊的初始体重和终末体重无显著（P>0.05）差异;试验组平均日增重较对照组降低10.84%,差异不显著（P>0.05）;对照组平均日采食量显著（P<0.05）高于试验组;两组试验羊料肉比相同。试验组滩羊血清中的总蛋白含量显著（P<0.05）高于对照组,其他血液生化指标无显著（P>0.05）差异。对照组滩羊屠宰率比试验组高1.59%,差异不显著（P>0.05）;两组试验羊肝脏重、肝脏指数、心脏和肺脏重、心脏和肺脏指数差异不显著（P>0.05）。试验组滩羊瘤胃液中丁酸浓度显著（P<0.05）高于对照组,异戊酸浓度显著（P<0.05）低于对照组。对照组和试验组滩羊背腰最长肌中分别检测出18种和20种脂肪酸,粗蛋白含量分别为17.51%和20.92%,粗脂肪含量分别为3.22%和3.89%,总氨基酸含量分别为13.25%和14.09%。[结论]颗粒日粮中加入柠条对滩羊生长性能、血液生化指标和屠宰性能影响不明显,但可改善瘤胃发酵,丰富羊肉中脂肪酸组成及含量,增加肉中粗蛋白、粗脂肪和氨基酸含量。     

Effect on Rendement Napole genotype on metabolic markers in Ossabaw pigs fed different levels of fat

We investigated effects of Rendement Napole (RN ) genotype on metabolic markers in Ossabaw pigs fed diets with different levels of dietary fat. Thirty‐two pigs, belonging to either the wild‐type (WT , rn⁺/rn⁺) or carrier (CAR , RN ^?/rn⁺) genotypes (n  = 16/genotype), were divided into two dietary groups, (high fat [HF ] or low fat [LF ]) diets, for 12 weeks (n  = 8 pigs/genotype/diet) after which pigs were killed for gene expression analysis by RT ‐PCR . Feeding HF diet caused increased daily gain (ADG , p  <  .05) and final body weight (BW ) (p  <  .05) in comparison with the LF diet (p  <  .05). Feed efficiency (gain:feed) was higher (p  <  .05) in pigs on the HF and was higher (p  <  .05) in CAR pigs compared to WT . There was genotype × diet interaction (p  =  .05) on final BW such that CAR animals on LF diet had the same final BW as animals of both genotypes on HF diet. Carrier pigs on LF diet had higher (p  <  .05) average daily gain and gain:feed than WT pigs. There was a trend (p  <  .08) for a higher feed consumption in pigs on the LF diet. Backfat thickness was higher (p  <  .01) in pigs on the HF diet. Serum triglyceride was higher (0.62 vs. 0.33 mg/dl, p  <  .01) in pigs on HF diet. Serum insulin was higher (p  <  .05) in CAR versus WT pigs (0.40 vs. 0.015 μg/ml). Pigs on the HF diet had a higher (p  <  .05) serum insulin compared to those on the LF diet (0.032 vs. 0.023 μg/ml). Carnitine palmitoyl transferase 1‐alpha was higher (p  <  .05) in the longissimus dorsi and semitendinosus muscles of pigs on HF diet. Acyl‐CoA oxidase I was elevated (p  <  .05) in the liver of pigs on HF diet. Fatty acid synthase was lower in the longissimus dorsi muscle, liver and mesenteric fat (p  <  .05) of carrier pigs. The RN gene regulates specific metabolic markers in the Ossabaw pigs.     

娟姗牛与西杂牛杂交后代生长发育观测

[目的]旨在繁育适于牦牛杂交改良的乳肉兼用父本.[方法]在海拔相对较低的半农半牧区,用娟姗牛与西杂牛杂交,观察杂交后代的生长发育和配种情况.[结果]娟姗牛与西杂牛的杂交后代在甘南州高海拔地区具有较好的适应性,表现出明显的杂交优势,能与甘南牦牛自然交配.     

功能性氨基酸在动物机体内的代谢利用与生理功能

氨基酸具有调节动物基因表达、促进小肠和骨骼肌的生长以及减少过多脂肪沉积等功能,而功能性氨基酸可在动物体中参与并调节动物健康水平与存活率、促进生长与发育、提高泌乳量与繁殖性能等关键代谢途径。论文对功能性氨基酸在动物机体中的代谢利用及生理功能进行了分析和综述,为进一步探索和解决功能性氨基酸"黑箱子"奥秘提供参考。