共查询到20条相似文献，搜索用时 234 毫秒
1.
对南美白对虾在温室大棚条件下高密度集约化反季节养殖过程中的摄食情况做了试验，证明养殖中后期是对虾摄食集中的时期，也是增重最快的时期，因此后期投饲具有举足轻重的地位。而在蜕壳期大部分对虾不摄食，应及时调节投饲量。 相似文献
2.
为测定条纹鲈对促摄食物质丙氨酸、丝氨酸、肌甙 - 5单磷酸盐、甜菜碱的适宜用量进行了试验。2 4 因子设计为 2种含量 (0、0 .1Ｍ ) 4种上述促摄食物质 ,测出结果表明相互作用显著。 4× 6因子设计 ,单独使用一种促摄食物质 ,用量为 0 %～ 8% ,国 外 篇测定最佳刺激效果的最低用量。试验结果表明 :使用量超过 1%无明显效果。与其他 3种促摄食物质相比 ,丙氨酸产生的反应较为明显。使用单因子方法测定每种促摄食物质的适宜用量 ,浓度为 0 %～ 1%。测出将 4种促摄食物质组合使用效果最佳 ,适宜比率分别为 :丙氨酸占凝胶载体的 0 .4 %、丝氨… 相似文献
3.
小肽在南美白对虾饲料中应用的研究 总被引：3，自引：0，他引：3
越来越多的生产实践及研究报道表明：水产动物可完整吸收利用饵料中的小肽类成分，添加小肽后的水产饲料可观察到明显的促摄食及促长效果。当然不同来源及不同饲喂对象，小肽的效果不尽相同。研究拟将某公司提供的小肽产品按不同比例添加到南美白对虾饲料中，以探讨其在虾料中的应用前景。 相似文献
4.
齐锦雯吴源冰王书瑶唐妮李志琼 《动物营养学报》2018,(4):1279-1285
促皮质激素释放激素(CRF)作为中枢调控的厌食欲因子,可使鱼类产生饱腹感,进而减少鱼类摄食量和体重增长率。CRF大量分布于下丘脑,刺激垂体分泌促皮质激素(ACTH),进一步刺激皮质醇释放,抑制机体摄食和能量代谢。本文依据CRF在哺乳动物和部分鱼类中的研究进展,阐述了CRF的发现历史、分子结构、对鱼类摄食的调控作用及其机制,为今后鱼类摄食调控和生长的研究以及生产提供理论依据。 相似文献
5.
6.
试验旨在研究黄粉虫粉作为饲料蛋白源对草鱼摄食和生长的影响，从而评价其在草鱼饲料中的应用价值。分别设计了以黄粉虫和豆粕为单一蛋白源的高、低蛋白质水平的4种饲料，并进行56 d的养殖试验，对比研究饲料蛋白源以及蛋白质水平对草鱼采食量、生长性能、嗅觉电信号响应和脑组织中摄食相关基因表达的影响。结果表明：草鱼对以黄粉虫粉为单一蛋白源的饲料摄食不佳，生长几乎处于停滞状态。对比分析发现，饲料蛋白源种类及蛋白质水平对平均摄食量、增重率、蛋白质效率、嗅觉电信号响应幅度和部分摄食相关基因（agrp和pomc）表达量影响显著，且因子间的交互作用显著。(1)比较以豆粕为蛋白源的饲料而言，黄粉虫粉饲料（L-MW和H-MW）组草鱼的摄食量、增重率、蛋白质效率和嗅觉电信号响应幅度显著降低（P<0.05）；摄食含黄粉虫饲料的草鱼脑组织中促食基因npy和agrp的表达量显著下调且抑食基因pomc和cart的表达量显著上调（P<0.05）。(2)以豆粕为蛋白源时，H-SM组草鱼摄食量、增重率和嗅觉电信号响应幅度均显著高于L-SM组，而蛋白质效率却显著下降（P<0.05）;H-SM饲料上调了促食基因np... 相似文献
7.
神经肽Y的促摄食作用及其调控 总被引：6，自引：2，他引：6
神经肽Y(NPY)是由36个氨基酸组成的活性单链多肽，有6种受体，经大量试验结果证明其在中枢系统可刺激动物采食。促摄食的NPY神经元起源于弓状核，投射到室旁核并释放NPY，在室旁核NPY与其受体Y1和Y5结合，最后通过抑制交感神经和兴奋副交感神经来引发强的摄食反应，最终增加能量沉积。机体的能量平衡状况是影响NPY分泌的决定性因素，它可通过一些外周和下丘脑的摄食调控因子来调控NPY的分泌；当能量处于正平衡时，Leptin和胰岛素分泌增加，使NPY的分泌受到抑制；当能量处于负平衡时，糖皮质激素、刺鼠相关肽(AGRP)、Ghrelin和苯基二氢咪唑啉(orexin)的分泌增加，它们能激活NPY神经元使NPY分泌增加。 相似文献
8.
金笑延陈秀梅林允杰王桂芹 《动物营养学报》2023,(12):7595-7604
摄食对鱼类生存、生长和繁殖至关重要。摄食过程主要受下丘脑中枢神经系统的调控,其中刺鼠相关蛋白(AgRP)神经元和阿片黑素促皮质激素原(POMC)神经元是控制摄食的2个关键神经元。本文通过梳理国内外文献,在概述AgRP/POMC神经元及其分布的基础上,分析其在摄食调控中的作用,并基于AgRP/POMC神经元途径探究调控鱼类摄食的策略,以期为鱼类等水产动物摄食调控研究提供参考。 相似文献
9.
南美白对虾为热带性虾类,其最适生长温度为23～30℃,当水温低于23℃时,南美白对虾的摄食量即开始明显下降,当水温低于20℃时,则处于应激状态,抗病力、生长速度、环境适应力等都显著下降。我国南方地区全年大部分时间的水温都比较适合南美白对虾的生长,但是在冬季和初春活虾价格较好的时候,其自然水温却不能满足南美白对虾的生长。在这种情况下,广东中山、珠海、 相似文献
10.
本研究以南美白对虾为研究对象,探究饲料中天蚕素抗菌肽的合适添加量。在饲料中依次添加不同浓度水平（0%、1%、2%、3%、4%和5%）的天蚕素抗菌肽,配制为6种配合饲料,用以投喂南美白对虾,饲养周期8周。结果显示：与对照组相比,饲料中添加天蚕抗菌肽对南美白对虾增重率、蛋白质沉积率和特定生长率有显著影响（P＜0.05）,高水平天蚕素抗菌肽会抑制南美白对虾的增重率和特定生长率,南美白对虾的饵料系数显著下降,但对南美白对虾存活率和摄食率无显著影响（P＞0.05）|随着饲料中天蚕素抗菌肽的添加水平不断增加,3%组南美白对虾的ACP、POD和SOD含量达到最大水平,与对照组有明显差异（P＜0.05）|随着饲料中天蚕素抗菌肽的添加水平的不断上升,3%组南美白对虾的淀粉酶、脂肪酶和胃蛋白酶含量最高,与对照组存在明显差异（P＜0.05）。结果表明,饲料中添加天蚕素抗菌肽显著提高南美白对虾的增重率和特定生长率,提高南美白对虾的生长发育速度,从而增强机体免疫力,提高南美白对虾的抗病能力。
[关键词]天蚕抗菌肽|南美白对虾|抗病力|免疫功能 相似文献
11.
12.
魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
13.
14.
本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
15.
REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
16.
17.
18.
Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献
19.
20.
以国际标准强毒Ｒ株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离ＭＧ,并收集感染鸡所产蛋分离ＭＧ。结果表明,人工感染４８小时后上、下呼吸道及肺已被全面感染,９６小时气囊已被感染,１２０小时输卵管已能分离到ＭＧ,卵巢始终分离不到ＭＧ。人工感染鸡自１４４小时便能在其所产蛋中分离出ＭＧ。药物治疗能在７２小时内消除感染,油乳剂苗则需２４天后逐渐降低蛋内ＭＧ分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内ＭＧ,但以研制的种蛋浸泡剂药浴效果为最好。 相似文献