Partially defatted black soldier fly larva meal inclusion in piglet diets: effects on the growth performance, nutrient digestibility,blood profile, gut morphology and histological features

Background:The aim of this trial was to investigate the effects of different inclusion levels of a partially defatted black soldier fly (BSF,Hermetia illucens L.) larva meal on the growth performance,nutrient digestibility,blood profile,gut morphology and histological features of piglets.A total of 48 newly weaned piglets were individually weighed (initial body weight (IBW):6.1 ± 0.16 kg) and randomly allocated to 3 dietary treatments (4 boxes as replicates/treatment and 4 animals/box).BSF larva meal was included at increasing levels (0% [BSF0],5% [BSFS] and 10% [BSF10]) in isonitrogenous and isoenergetic diets formulated for two feeding phases:Ⅰ (from d 1 to d 23) and Ⅱ (from d 24 to d 61).The weight gain (WG),average daily gain (ADG),average daily feed intake (ADFI) and feed conversion ratio (FCR) were calculated for each feeding phase and for the whole trial.The haematochemical parameters and nutrient digestibility of the piglets were also evaluated.A total of 3 piglets per box were slaughtered on d 61 and the slaughtered piglets were submitted to morphometric investigations and histopathological examinations.Results:No overall significant differences were observed for growth performance (P > 0.05),except for the ADFI of phase Ⅱ,which showed a linear response to increasing BSF meal levels (P < 0.05,maximum for the BSF10 group).Dietary BSF meal inclusion did not significantly influence the blood profile,except as far as monocytes and neutrophils are concerned,and these showed a linear and quadratic response,respectively,to increasing BSF meal levels (P < 0.05,maximum for the BSF10 and BSF5 groups,respectively).On the other hand,the nutrient digestibility,gut morphology and histological features were not affected by dietary BSF meal inclusion (P > 0.05).Conclusions:The obtained results show that a partially defatted BSF larva meal can be used as a feed ingredient in diets for weaned piglets without negatively affecting their growth performance,nutrient digestibility,blood profile,gut morphology or histological features.

Effects of dietary Hermetia illucens meal inclusion on cecal microbiota and small intestinal mucin dynamics and infiltration with immune cells of weaned piglets

Background: The constant interaction between diet and intestinal barrier has a crucial role in determining gut health in pigs. Hermetia illucens(HI) meal(that represents a promising, alternative feed ingredient for production animals) has recently been demonstrated to influence colonic microbiota, bacterial metabolite profile and mucosal immune status of pigs, but no data about modulation of gut mucin dynamics are currently available. The present study evaluated the effects of dietary HI meal inclusion on the small intestinal mucin composition of piglets, as well as providing insights into the cecal microbiota and the mucosal infiltration with immune cells.Results: A total of 48 weaned piglets were randomly allotted to 3 dietary treatments(control diet [C] and 5% or10% HI meal inclusion [HI5 and HI10], with 4 replicate boxes/treatment and 4 animals/box) and slaughtered after61 days of trial(3 animals/box, 12 piglets/diet). The cecal microbiota assessment by 16 S r RNA amplicon based sequencing showed higher beta diversity in the piglets fed the HI-based diets than the C(P < 0.001). Furthermore,the HI-fed animals showed increased abundance of Blautia, Chlamydia, Coprococcus, Eubacterium, Prevotella,Roseburia, unclassified members of Ruminococcaceae, Ruminococcus and Staphylococcus when compared to the C group(FDR < 0.05). The gut of the piglets fed the HI-based diets showed greater neutral mucin percentage than the C(P < 0.05), with the intestinal neutral mucins of the HI-fed animals being also higher than the sialomucins and the sulfomucins found in the gut of the C group(P < 0.05). Furthermore, the piglets fed the HI-based diets displayed lower histological scores in the jejunum than the other gut segments(ileum [HI5] or ileum and duodenum [HI10], P < 0.05).Conclusions: Dietary HI meal utilization positively influenced the cecal microbiota and the small intestinal mucin dynamics of the piglets in terms of selection of potentially beneficial bacteria and preservation of mature mucin secretory architecture, without determining the development of gut inflammation. These findings further confirm the suitability of including insect meal in swine diets.

Dietary proline supplementation alters colonic luminal microbiota and bacterial metabolite composition between days 45 and 70 of pregnancy in Huanjiang mini-pigs

Background: Pregnancy is associated with important changes in gut microbiota composition. Dietary factors may affect the diversity, composition, and metabolic activity of the intestinal microbiota. Among amino acids, proline is known to play important roles in protein metabolism and structure, cell differentiation, conceptus growth and development, and gut microbiota re-equilibration in case of dysbiosis.Results: Dietary supplementation with 1% proline decreased(P < 0.05) the amounts of Klebsiella pneumoniae,Peptostreptococcus productus, Pseudomonas, and Veillonella spp. in distal colonic contents than that in the control group. The colonic contents of Butyrivibrio fibrisolvens, Bifidobacterium sp., Clostridium coccoides, Clostridium coccoides-Eubacterium rectale, Clostridium leptum subgroup, Escherichia coli, Faecalibacterium prausnitzii,Fusobacterium prausnitzii, and Prevotella increased(P < 0.05) on d 70 of pregnancy as compared with those on d 45 of pregnancy. The colonic concentrations of acetate, total straight-chain fatty acid, and total short-chain fatty acids(SCFA) in the proline-supplemented group were lower(P < 0.05), and butyrate level(P = 0.06) decreased as compared with the control group. Almost all of the SCFA displayed higher(P < 0.05) concentrations in proximal colonic contents on d 70 of pregnancy than those on d 45 of pregnancy. The concentrations of 1,7-heptyl diamine(P = 0.09) and phenylethylamine(P < 0.05) in proximal colonic contents were higher, while those of spermidine(P = 0.05) and total bioamine(P = 0.06) tended to be lower in the proline-supplemented group than those in the control group. The concentrations of spermidine, spermine, and total bioamine in colonic contents were higher(P < 0.05) on d 70 of pregnancy than those measured on d 45 of pregnancy. In contrast, the concentration of phenylethylamine was lower(P < 0.05) on d 70 than on d 45 of pregnancy.(Continued on next page)(Continued from previous page)Conclusion: These findings indicate that L-proline supplementation modifies both the colonic microbiota composition and the luminal concentrations of several bacterial metabolites. Furthermore, our data show that both the microbiota composition and the concentrations of bacterial metabolites are evolving in the course of pregnancy. These results are discussed in terms of possible implication in terms of luminal environment and consequences for gut physiology and health.

Development of a recombinant pB602L-based indirect ELISA assay for detecting antibodies against African swine fever virus in pigs

African swine fever(ASF),caused by the African swine fever virus(ASFV),is a devastating disease of domestic and wild pigs.There is no effective vaccine,and the control of the disease relies mainly on surveillance and early detection of infected pigs.Previously,serological assays,such as ELISA,have been developed mainly based on recombinant structural viral proteins of ASFV,including p72,p54,and p30.However,the antibodies against these proteins do not provide efficient protection against ASFV infection in pigs.Therefore,new serological assays that can be applied for clinical diagnosis and evaluating serological immune response in vaccinated pigs are still required.In this study,we expressed and purified a recombinant p B602 L protein.The purified p B602 L protein was then used as an antigen to develop an indirect ELISA assay.This assay has no cross-reaction with the anti-sera against the 15 most common pig pathogens in China,such as classical swine fever virus,pseudorabies virus,and porcine parvovirus.This assay and a commercial ELISA kit were then used to detect 60 field pig serum samples,including an unknown number of antiASFV sera.The coincidence of the two assays was 95%.Furthermore,the p B602 L-based ELISA was employed to test the antibody responses to the seven-gene-deleted ASFV strain HLJ/18-7 GD in pigs.The results showed that the antibody levels in all vaccinated pigs,starting from the 10 th day post-inoculation,have increased continuously during the observation period of 45 days.Our results indicate that this p B602 L-based indirect ELISA assay can be employed potentially in the field of ASFV diagnosis.

Effects of Different Protein Energy Ratios on Fattening Performance,Slaughter Performance and Meat Quality of Pigs

[Objectives]Protein energy ratio refers to the proportional relationship between protein and energy levels in animal diets,i.e.,the grams of crude protein corresponding to every megacalorie of energy,which is generally expressed as CP:ME or CP:DE.This study was conducted to investigate the effects of different diets on fattening and slaughter performance and meat quality traits for"L(Large Yorkshire)×L(Landrace)"crossbred pigs.[Methods]Eighteen piglets of L×L crossbred with similar body weights about 51 kg were selected.The piglets were divided into 3 groups randomly and each group was assigned to 3 replicates with 2 piglets in a replicate.Group A was fed diet Ⅰ (control diet),group B was fed the same diet of group A in the first month of the trial but fed diet Ⅱ in second month,and group C consumed diet Ⅲ.All the pigs were fed in the same feeding condition for two months except the different diets during the trial.One pig in similar body weight from each replicate was slaughtered for the determination of slaughter performance and meat quality traits in the end of the trial.[Results]The average daily feed intake(ADFI)of pigs from group B was only(2.32±0.52)kg and significantly lower than those from group A and group C(P<0.05),but no difference was found in average daily gain(ADG) and feed/gain(P>0.05).Also,no differences occurred in the carcass length,back fat thickness,longissimus muscle (LM) area and dressing percentage(P>0.05).In addition,no differences were found in the meat quality traits of shear force,meat color,pH_(45 min),pH_(24 h) and cooking loss(P>0.05).However,the water-holding capacity of meat from group C was(2.58±0.02)ms and significantly lower than that of(2.80±0.20)ms from group A(P<0.05).Although the contents of glutamic acid and cystine in LM from group B was significantly lower than those from group A and group C(P<0.05),no differences occurred in the contents of other amino acids,the total amino acid and total flavor amino acid among the three groups(P>0.05).However,the inosine monophosphate content of LM from group C was only(331.80±11.53)mg/100 g and significantly lower than those of(361.00±6.36)and(366.37±4.80)mg/100 g from group A and B(P<0.05).Even though no differences were found in the contents of DM and CP in LM among the three groups of pigs,the content of intramuscular fat(IMF)in LM from group B and group C was increased by 45.6%and 46.58%respectively from that of group A(P<0.05),but no difference occurred between group B and C(P>0.05).[Conclusions]DietsⅡ and Ⅲ in this study caused no differences in fattening and slaughter performance of L×L crossbred pigs,but the effects on some meat traits were still significant,especially on the improvement of intramuscular fat in experimental pigs.Therefore,they could improve the meat quality of crossbred pigs to a certain extent.

Metabolism of Glucotropaeolin from Tropaeolum majus L.(Nasturtium)and the Bioavailability of Benzyl-Isothiocyanates in Growing Pigs

Tropaeolum majus L. is widely known as a medicinal plant in human medicine. It belongs to the Tropaeolaceae which contains mustard oil glycosides like cruciferous plants. In the case of T. majus, the intact glucosinolate glucotropaeolin showed no biological activity, but their degradation products, the isothiocyanates, did. The substances are thought to be enriched in the urinary bladder and the lungs, the active sites to develop their antimicrobial effectiveness. In animal nutrition these effects are of interest in sow management and piglet rearing. Therefore, the kinetics of benzyl-isothiocyanat (BITC) in plasma and the excretion with pig urine in response to nasturtium supplementation at different dosing regimens and galenic forms were examined. Four different groups with catheterized pigs were studied. The animals received the T. majus in different dosages (2.3, 6.9 and 13.4 mg GTL/kg BW) and different galenic forms (enteric coated tablets, pulverized tablets and powder) admixed to the feed ration as single bolus to the morning feeding. Blood and urine samples were collected within 24 h after nasturtium intake and analyzed for free BITC. The results indicated that the enteric coating was not effective in animal feeding. The concentration of BITC in tablet fed pigs was lower compared to animals fed powder or pulverized tablets. The bio-availability of the tablets was only 45% within 24 h relative to pulverized tablets. Nevertheless, the tablets could have some advantages in terms of the handling, the stability of the active substance and the dosing. Furthermore, it could be shown that all dosages yielded concentrations in urine and plasma, which can be considered to have an antimicrobial effect.

L-精氨酸对脂多糖刺激断奶仔猪生产性能、血液生化指标和内脏器官重量的影响

试验研究L-精氨酸(Arg)对脂多糖(LPS)刺激断奶仔猪[(21±1)d,平均体重(5.78±0.26)kg]生产性能、血液生化指标和内脏器官重量的影响。试验采用单因子设计,分为以下4个处理组:(1)基础日粮(非应激对照组);(2)基础日粮+LPS(应激对照组);(3)基础日粮+LPS+0.5%Arg(0.5%Arg组);(4)基础日粮+LPS+1.0%Arg(1.0%Arg组)。在试验第16天,给处理2、处理3和处理4组仔猪按每千克体重注射100μgLPS,处理1组注射等量的生理盐水,3h后采血。试验第18天屠宰仔猪测定内脏器官的重量。结果表明:(1)LPS刺激导致断奶仔猪日增重和日采食量显著下降(P<0.001),而0.5%Arg可缓解LPS刺激所导致的日增重下降(P<0.001);(2)LPS刺激导致断奶仔猪血浆葡萄糖、总蛋白、白蛋白和球蛋白含量显著降低(P<0.05),而0.5%或1.0%Arg可在一定程度上缓解LPS刺激导致的血浆总蛋白、白蛋白和球蛋白含量降低;(3)LPS刺激导致胃绝对重量显著降低(P<0.05)和肝脏相对重量增加(P<0.05),0.5%或1.0%Arg可在一定程度上缓解LPS刺激导致的胃绝对重量的减轻和肝脏相对重量的增加。这表明Arg在一定程度上缓解了LPS刺激所导致生长抑制和应激反应。

异甘草素对豚鼠心室肌细胞L型钙通道的影响

目的:研究异甘草素对豚鼠单个心室肌细胞膜ICa-L通道的影响,旨在探讨其抗心律失常的机制。方法:采用全细胞膜片钳技术,观察不同浓度的异甘草素对ICa-L的作用。结果:①异甘草素能使I-V曲线明显上移。②异甘草素0.1-100μmol/L对ICa-L呈浓度依赖性的抑制作用。③3μmol/L异甘草素具有频率依赖性的抑制作用,它能使ICa-L稳态激活曲线右移、失活曲线左移,还能增加失活后恢复的τ值。结论:提示异甘草素对ICa-L通道的激活态和失活态有较高亲和力,这些可能成为其抗心律失常作用的机制。

谷氧还蛋白1和硫氧还蛋白1基因在云南乌金猪不同组织中的表达特点及L-组氨酸对其在氧化应激细胞中表达的影响

本试验旨在研究抗氧化基因谷氧还蛋白1(GRX1)、硫氧还蛋白1(TRX1)在云南乌金猪脑垂体、下丘脑、甲状腺、胸腺、胰腺、生殖腺、肝脏、皮肤、十二指肠、空肠、回肠11种组织中的差异表达,探讨L-组氨酸对乌金猪氧化应激细胞中GRX1、TRX1基因表达的调节作用。采用实时荧光定量PCR(RT-qPCR)方法检测乌金猪组织中GRX1、TRX1基因表达;以过氧化氢(H2O2)为氧化应激源建立氧化应激细胞模型,探讨L-组氨酸对GRX1、TRX1基因表达的调节作用。结果表明:1)GRX1、TRX1基因在乌金猪被检测组织中均有表达,肝脏表达量最高,其次是皮肤、空肠,其他组织中的表达量相对较低;2)乌金猪组织中TRX1基因表达量明显高于G RX1基因表达量;3)细胞培养结果表明,受到H2O2刺激时,氧化应激细胞中GRX1、TRX1基因产生过表达,L-组氨酸对氧化应激细胞或非应激细胞中GRX1、TRX1基因表达具有调节作用,其适宜浓度约为280μg/mL。乌金猪GRX1、TRX1基因表达具有明显组织特异性,H2O2可诱导氧化应激细胞中GRX1、TRX1基因产生过表达,添加适宜浓度的L-组氨酸可以调节氧化应激细胞或非应激细胞中GRX1、TRX1基因表达。结果提示,通过营养途径可诱导乌金猪体内G RX1、TRX1基因的表达,这是缓解机体氧化应激损伤和增强抗氧化能力的一种有效方式。

N-甲基D,L-天冬氨酸对肥育猪生长性能和胴体品质的影响

本试验以杜长大肥育猪为试验对象 ,研究了N 甲基D ,L 天冬氨酸对其生长性能和胴体品质的影响。结果表明 ,在日粮中添加 50mg/kgN 甲基D ,L 天冬氨酸使肥育猪 ( 1 )日增重提高 9.31 % (P <0 .0 1 ) ,饲料转化率提高 7.1 6 % (P <0 .0 2 ) ;( 2 )胴体瘦肉率提高 6 .53% (P <0 .0 1 ) ,脂肪比率降低 1 1 .76 %(P <0 .0 1 ) ,背膘厚降低 1 9.72 % (P <0 .0 1 ) ,眼肌面积提高 2 1 .0 1 % (P <0 .0 4 ) ;( 3)背最长肌、股二头肌和半膜肌重量分别增加 1 1 .3% (P <0 .0 1 )、1 0 .0 9% (P <0 .0 1 )和 1 4 .4 4% (P <0 .0 1 )。

丹参酮Ⅱ-A抑制豚鼠单个心肌细胞L型钙电流和缩短动作电位时程效应的相关性分析

目的旨在探讨药物阻断L型钙电流与其缩短心肌细胞动作电位时程（APD）效应之间的相互关系。方法采用膜片钳全细胞式记录方法，同时观察了丹参酮Ⅱ-A（DST）对豚鼠同一个心室肌细胞跨膜电位和L型钙电流的影响，并对药物的有关效应作相关分析。结果DST显著缩短豚鼠心肌单细胞的动作电位时程（APD），呈剂量依赖关系（r=-0.987）;10、20、和40μmol·L-1DST可使L型钙内向峰电流分别减少35.2％、57.7％和74.7％，亦呈浓度依赖方式（r=-0.948）。经相关性分析证实，在本实验采用的DST相应浓度作用下，APDS50、APD90和APD50～10的缩短与L型钙电流峰值的减少之间呈高度正相关（r分别为0.9870、0.9867和0.9896）。结论DST缩短心肌细胞APD和阻断L型钙电流的效应是高度一致的，且以APD50～10表示平台期的长短更合理。

L-半胱氨酸对冻融后猪精子质量参数和膜脂质过氧化反应的影响

试验检测冷冻稀释液中添加L-半胱氨酸对冻精解冻后精子质量参数、膜脂质过氧化程度的影响。结果显示:(1)在冷冻稀释液中添加0.1 mg.mL-1L-半胱氨酸能显著地提高冻融后精子的活率、顶体完整率及体外受精率(P<0.05),但对运动学参数没有影响(P>0.05)。(2)在冷冻稀释液中添加L-半胱氨酸(0.1、0.2和0.3mg.mL-1L-半胱氨酸)能显著降低膜脂质过氧化水平(P<0.05)。该结果表明冷冻稀释液中添加L-半胱氨酸能改善猪精子的冷冻效率。

救心复脉注射液对豚鼠心室肌细胞L型钙电流的影响

目的 :探讨救心复脉注射液 (枳实提取液 )有效成分辛弗林 (311)、N 甲基酪胺 (4 17)对豚鼠心室肌细胞膜L型钙通道电流 (ICa L)的影响。方法 :用酶解法分离单个心室肌细胞 ,采用全细胞膜片钳技术 ,观察辛弗林、N 甲基酪胺对豚鼠心室肌细胞膜ICa L的影响。结果 :用辛弗林 (10 ,2 5 ,5 0 ,10 0mmol/L)时能增大ICa L,增加率分别为 8.2 7% ,2 7.2 9% ,4 1.0 1%和 4 8.74 % (P <0 .0 5 )。用N 甲基酪胺 (10 ,2 5 ,5 0 ,10 0mmol/L)时能增大ICa L,增加率分别为 10 .0 5 % ,30 .12 % ,4 3.0 5 %和 5 1.90 % (P <0 .0 5 )。辛弗林和N 甲基酪胺只改变电流幅度 ,不改变I V曲线形状。结论 :辛弗林和N 甲基酪胺有浓度依赖性的增大豚鼠心室肌细胞ICa L。

L-脯氨酸与L-苯丙氨酸对美拉德反应产物烤香味的影响

目的:以猪骨素和羊骨素酶解产物为基料,研究L-脯氨酸(L-proline)和L-苯丙氨酸(L-phenylalanine)对美拉德反应产物的烤香味的影响。方法:在美拉德反应中添加L-脯氨酸和L-苯丙氨酸,以吡嗪类化合物为主要烤香味目标风味物质,采用SPME-GC-MS分析产物挥发性成分,研究两种氨基酸对反应产物的烤香味的影响。结果:当仅添加L-脯氨酸时,其烤香增加明显,但同时加入L-脯氨酸和L-苯丙氨酸反而不利于烤香生成。与对照组(无添加L-proline和L-phenylalanine)相比,配方中添加2 g L-脯氨酸后,吡嗪类化合物相对含量增加5.00%,是对照组的2.2倍;配方中同时添加1 g L-苯丙氨酸和2 g L-脯氨酸后,吡嗪类化合物仅比对照组高出0.67%,与仅添加2 g L-脯氨酸的配方相比,吡嗪类化合物相对含量反而降低了4.33%。结果表明,仅添加L-脯氨酸更有利于美拉德反应产物烤香味风味物质生成。结论:本文明确了L-脯氨酸和L-苯丙氨酸对美拉德反应产物的烧烤香味的影响。

枳实提取液对豚鼠心室肌细胞L型钙电流的影响

目的 :探讨枳实提取液 (CAE)对豚鼠心室肌细胞膜L型钙通道电流 (ICa L)的影响。方法 :用酶解法分离单个心室肌细胞 ,采用全细胞膜片钳技术 ,观察枳实提取液对豚鼠心室肌细胞膜ICa L的影响。结果 :①CAE(4×10 3 ,2× 10 2 ,4× 10 2 ,1× 10 1)g/ml增大ICa L,增加率分别为 15 .89%,2 9.0 1%,5 2 .0 3%和 5 9.76 %(P <0 .0 5 )。②CAE 2× 10 1g/ml和 4× 10 1g/ml分别可使峰值ICa L减少 17.33%和 30 .0 9%(P <0 .0 5 )。CAE只改变电流幅度 ,不改变I V曲线形状。结论 :低浓度CAE ,可浓度依赖性的增大豚鼠心室肌细胞L型钙电流 ,有促进钙通道开放的作用。高浓度CAE ,可抑制心室肌细胞L型钙电流 ,有抑制钙通道开放的作用。

N-甲基-D,L-天冬氨酸(NMA)对育肥猪生长激素基因表达的影响

以肥育猪为对象 ,探讨了日粮中添加 5 0 mg/ kg N-甲基 - D,L-天冬氨酸 (NMA)对其生长激素 (GH)基因表达的影响。结果显示 ,添加 NMA后 ,肥育猪日增重提高了 9.31% (P<0 .0 1) ;料重比降低了 7.16 % (P<0 .0 2 ) ;血清 GH含量提高了 92 .5 4% (P<0 .0 1) ;垂体 GH- m RNA水平提高了 15 3.0 3% (P<0 .0 1) ;下丘脑 c AMP水平降低了 2 1.89%(P<0 .0 1) ;腺垂体中 c AMP水平升高 88.5 7% (P<0 .0 5 )

L-甲状腺素引起肥厚心肌细胞膜上^(125)I多非替利结合点的改变

目的 研究致死性心律失常病理模型中IKr通道的变化。方法 用I12 5标记选择性IKr阻断剂多非替利 (dofetilide)进行受体结合实验 ,观察L 甲状腺素引起的心脏重构病变模型中心肌细胞膜上IKr的变化。结果 正常心肌细胞膜上与IKr通道相关的多非替利高亲和性结合点的Bmax为 34 7nmol·g-1(n =5 ) ,在L 甲状腺素引起的肥大心肌细胞膜上多非替利的高亲和性结合点Bmax为 18 1nmol·g-1(n =6 )。应用钙拮抗剂维拉帕米 (n =5 )和IKr阻断剂多非替利 (n =5 )介入后 ,Bmax分别为 37 8nmol·g-1和 2 2 3nmol·g-1。结论 在L 甲状腺素引起的心脏肥大病变模型中IKr通道蛋白质密度下调 ,用药物介入可以使IKr通道上调 。

猪胆囊中沙门菌L型的分离培养与invA基因检测

为了解猪胆囊中沙门菌L型携带情况,在贵阳市屠宰场采集970例健康生猪的胆囊组织与胆汁标本,用常规细菌学方法和非高渗分离培养法分离沙门菌及其细菌L型,用PCR和核酸序列分析方法对稳定L型纯培养物进行沙门菌的invA基因检测。结果显示,970例生猪胆囊标本未检出沙门菌细菌型,细菌L型检出率为8.25%;80例细菌L型分离物中有50例invA检测阳性,占5.15%;占细菌L型阳性分离物62.50%。研究结果为生猪胆囊沙门菌L型感染的流行病学及其检查提供了依据。

L-茶氨酸对育肥猪生长性能和血液生化指标影响的研究

试验旨在探究L-茶氨酸对育肥猪生长性能、血液生化指标及免疫因子的影响。选择育肥猪72头[(60.0±2.0)kg],随机分为4组,每组18个重复。对照组饲喂玉米-豆粕型日粮,试验1、2、3组分别在基础日粮中添加200、500 mg/kg和1 000 mg/kg L-茶氨酸,试验期37 d。结果表明:1与对照组相比,试验3组的平均日增重和日采食量均显著增加(P<0.05),试验1、2组无显著差异(P>0.05);2与对照组相比,三个试验组血液中的谷丙转氨酶(ALT)、谷草转氨酶(AST)、白蛋白(ALB)和血糖(GLU)水平无显著性变化(P>0.05),试验2组和试验3组血液总蛋白(TP)水平显著升高(P<0.05);3与对照组相比,三个试验组丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-Px)水平无显著性差异,试验3组的皮质醇(COR)和碱性磷酸酶(ALP)均显著降低(P<0.05),试验2组的皮质醇(COR)显著降低(P<0.05);4与对照组相比,试验2、3组的免疫球蛋白G(IgG)水平显著增加(P<0.05),白介素因子10(IL-10)的水平显著降低(P<0.05),免疫球蛋白A、M(IgA、IgM)的水平无显著差异(P>0.05)。综上所述,日粮中添加1 000 mg/kg的L-茶氨酸可增强育肥猪血液抗氧化和免疫能力,促进育肥猪生长。

17β-雌二醇对豚鼠心室肌细胞动作电位及L型钙通道电流的影响

探讨雌激素对心血管保护作用的机制，采用标准玻璃微电极技术及全细胞膜片钳技术观察17β-雌二醇（ES）对豚鼠心室乳头肌细胞动作电价的影响及其对分离的豚鼠心室肌细胞的L型钙通道电流的作用。结果：30μmol／LES灌流心肌30min可明显缩短动作电位时程；复极20％动作电位时程及复极50％动作电位时程分别由146±22ms，213±21ms缩短至87±6ms，107±11ms（P均＜0．01）。1，10，20，30μmol／LES是浓度依赖性抑制L型钙通道电流（P均＜0．01），抑制率分别为8％，18％，33％，43％。结论：ES是一种内源性的钙离子通道拮抗剂，这可能是其心血管保护作用的重要机制之一．