Inflammation-related changes in cyclic AMP and cyclic GMP in bovine mastitis

Cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) cocentrations in milk and plasma samples from healthy and mastitic cows were determined by radioi-immunoassay and compared with prostaglandins (PGE2, PGF2 and thromboxane B2 [TXB2]), phospholipids and other relevant parameters in milk and blood. The concentrations of cAMP were about five times higher in plasma (p<0.01) than in milk, whereas the cGMP concentration in milk was three times higher (p<0.01) than that in plasma in both healthy and diseased animals. In mastitic milk, the cAMP and cGMP concentrations were 19% and 65% and in blood plasma 13% and 84% higher respectively than in healthy animals. In milk, cyclic nucleotide concentrations correlated with the markedly elevated cell count and also with the prostaglandin concentration and pH. In blood, cAMP correlated positively with phospholipids and cGMP with reduced glutathione (GSH). These changes are considered to be important in the disease process and, in particular, the increase in cGMP deserves further study.     

冻结和冻藏对中华绒螯蟹蟹肉品质的影响

为了研究冻结和冻藏对中华绒螯蟹蟹肉品质的影响,本研究对冻结和冻藏中华绒螯蟹的蛋白质特性、游离氨基酸、核苷酸关联成分、Ca2+-ATPase活性以及解冻汁液流失率进行了全面的评价。中华绒螯蟹较耐冻结但不耐冻藏,冻藏2周后蟹肉弹性程度开始下降。中华绒螯蟹在冻藏过程中,蟹肉中游离氨基酸、呈味核苷酸、Ca2+-ATPase活性以及解冻汁液流失率都发生明显变化。冻藏12周后相对于新鲜蟹,游离氨基酸、呈味核苷酸、Ca2+-ATPase活性以及解冻汁液流失率分别下降了25.3%、100%、41.6%和增加了9.2%。普通冻藏(-20℃)条件下,中华绒螯蟹蟹肉发生快速蛋白质分解和ATP降解,表现为游离氨基酸成分与ATP关联物成分都发生很大变化,蛋白质变性显著、汁液流失现象严重等。推测中华绒螯蟹蟹肉不耐冻藏可能与其自身的自溶酶和ATP酶类有关。     

Immunostimulant effects of nucleotide isolated from yeast RNA on carp, Cyprinus carpio L.

Nucleotides from yeast RNA were evaluated for their ability to enhance the non-specific immune responses in carp, Cyprinus carpio . Oral administration of nucleotides to fish daily for 3 days resulted in enhanced responses of phagocytic and nitroblue tetrazolium (NBT) activities in kidney phagocytic cells. This activation of kidney cells was observed for at least 10 days post-treatment. The serum complement and lysozyme activities also increased in fish treated with nucleotides. Furthermore, the number of Aeromonas hydrophila in nucleotide-treated fish significantly decreased in the blood, kidney and liver after intraperitoneal injection. Thus yeast nucleotides appear to enhance non-specific immune responses in fish.     

乳中环核苷酸提取方法研究

根据环核苷酸理化性质及乳的特点，采用酶法从乳汁中提取环核苷酸。研究表明，该方法条件温和、工艺合理、操作方便。经放射免疫测定提取浓缩液浓度为ｃＡＭＰ２０μｍｏｌ·Ｌ－１，ｃＧＭＰ０．２μｍｏｌ·Ｌ－１．     

尼罗罗非鱼制作传统上海熏鱼过程中的风味变化

为探究上海熏鱼制作过程中不同加工阶段风味物质的变化,本研究以尼罗罗非鱼肉为对象,通过高效液相色谱法、氨基酸自动分析法和固相微萃取—气相色谱—质谱联用技术对上海熏鱼4个加工阶段(生鲜罗非鱼、一次浸渍、一次浸渍后油爆和上海熏鱼成品)的风味物质进行分析和鉴定。结果显示,各阶段IMP含量呈逐渐上升趋势,是主要的鲜味核苷酸。游离氨基酸总量和呈味氨基酸含量也逐渐升高,并呈显著性差异,其中天冬氨酸和谷氨酸对上海熏鱼风味影响最大。生鲜罗非鱼、一次浸渍、一次浸渍后油爆和上海熏鱼成品中挥发性物质依次为50、84、78和82种,主要由醛类、酮类、醇类和烃类构成。因此,浸渍和油爆是上海熏鱼风味形成的主要原因,使得罗非鱼鱼体的腥味得以有效改善。     

Dietary nucleotides enhance growth performance,feed efficiency and intestinal functional topography in European Seabass (Dicentrarchus labrax)

Nucleotides, nucleosides and nucleic acids (NU) have many critical functions in supporting life and increasing evidence suggests that exogenous supply can benefit the health of mammals and fish. For these reasons, a 6‐week feeding trial was conducted on juvenile European seabass (Dicentrarchus labrax) with diets containing 0%, 0.15% and 0.3% inclusion of a NU mixture (Laltide^®) derived from the yeast Saccharomyces cerevisiae. At the end of the study no significant differences were found in fish performance, although a tendency towards better performance was indicated in fish fed the Nu0.3 diet. In relation to histological assessment, a significantly greater perimeter ratio; internal to outer (IP/OP) was observed in the posterior intestine of fish fed supplemental NU. Microvilli heights in the posterior intestine were also shown to be significantly promoted in fish fed NU diets (p < 0.05). Goblet cell abundance was shown to be unaffected by the inclusion of NU in the diet (p > 0.05). Overall, this study indicates that orally administered NU may be effective promoters of gut functional topography with marginal associated improvements to fish performance. Nonetheless, longer exposure and/or commercial scale application, and in diets that were challenging in use of high inclusion levels of plant by‐products would potentially amplify improvements in production characteristics, in turn benefiting fish culturists.     

核苷酸对动物摄食、生长与免疫功能的影响

饲料中的核苷酸对动物生长发育和免疫功能等具有重要作用。核苷酸作为一种无毒无害无残留的新型饲料添加剂,在动物营养方面有很大的发展前途。近年来国内外学者对核苷酸的研究逐渐增多。本文从促生长、诱食和改善免疫功能等方面对核苷酸在动物营养方面的应用做一综述。     

Effects of dietary nucleotides on growth,survival and metabolic response in whiteleg shrimp,Litopenaeus vannamei against ammonia stress condition

This trial was conducted to evaluate the effects of nucleotides on growth of whiteleg shrimp, Litopenaeus vannamei, and the survival and metabolic responses to ammonia stress test. Experimental diets were as follows: low fish meal diet (LFMD), and four LFMD test diets, each supplemented with 0.1% guanosine monophosphate (GMP), 0.1% inosine monophosphate (IMP), 0.1% mixture of GMP and IMP and 0.1% mixture of GMP, IMP, uridine monophosphate (UMP) and cytidine monophosphate (CMP). The shrimp specimens (initial body weight: 0.99 ± 0.01 g) were randomly allocated into five groups and fed four times daily for 8‐weeks. After the trial, final body weight was recorded and haemolymph was withdrawn for haematological analysis. The shrimp was then challenged with 70 mg/L ammonia (LC50) for 10 days. Survival and haemolymph of the shrimp were taken after exposure to ammonia. The highest growth performance was observed in the shrimp fed diet supplemented with GMP (p < .05), while survival was not influenced by the test diets in the feeding trial. In the ammonia challenge test, the highest survival was observed in the shrimp fed GMP supplemented diet compared to others. The plasma protein, glucose and cholesterol levels increased in all the treatments while triglycerides level decreased post challenge. Cortisol level recovered at day 10th after the challenge. Shrimps fed with nucleotides diets showed higher protein and glucose level compared to control groups post challenge. In general, nucleotides supplemented in the diet enhanced growth, improved stress resistance while modulating the haemolymph metabolites in L. vannamei under ammonia stress.     

日粮核苷酸对机体炎症抗炎症平衡体系的影响

为探讨日粮核苷酸对小鼠炎症／抗炎症平衡体系的作用，用CpG DNA和脂多糖（LPS）刺激小鼠构建炎症反应模型，观察分别饲喂无核苷酸（NF）日粮和核苷酸（NT）日粮小鼠的炎性细胞因子IL-1、IFN-λ，、抗炎性细胞因子IL-10水平和小肠髓过氧化物酶（MPO）活性变化。结果显示，在刺激后第4h时，NT组小鼠的IL-1（P〈0．05）、IFN-λ，（P〈0．01）和小肠MPO（P〈0．01）明显低于NF组，IL-10（P〉0．05）高于NF组；刺激后第18h时，NT与NF组的IL-1（P〈0．01）、IFN-λ，（P〈0．01）、IL-10（P〉0．05）和MPO（P〈0．01）均较刺激后第4h有所降低，NT组的IL-1（P〉0．05）、IFN-λ，（P〈0．05）和小肠MPO（P〈0．05）仍低于NF组，IL-10（P〉0．05）仍高于NF组。表明，日粮核苷酸对CpG DNA或LPS所诱导的炎症反应有明显的抑制作用，有助于维持机体炎症／抗炎症平衡，保护机体免受炎症损伤。     

外源性环核苷酸对AA肉鸡脂肪和蛋白质代谢的影响

选用初生健康AA肉鸡 2 4 0只 ,随机分为 2组 ,每组 12 0只 ,每组内设 3个重复 :I组为试验组 ,每隔 4d皮下注射标准环核苷酸组合剂 ,剂量为每只鸡 0 1mL ;Ⅱ组为对照组 ,注射等量的生理盐水 ,共计 4 9d。研究结果表明 ,试验组鸡肝脏组织中总RNA、mRNA分别比对照组提高2 9 84 %和 2 6 0 3%。经单因子方差分析 ,组间均存在着显著差异 (P <0 0 1) ,血浆中cAMP和cGMP的浓度显著高于对照组 (P <0 0 1) ;血清中生长激素浓度升高 37 70 % ,球蛋白浓度提高了 34 0 9% ,甘油三酯浓度显著高于对照组 (P <0 0 1) ,尤其GOT、GPT等酶活性均有显著提高 (P <0 0 1)。