Effect of feeding sun-dried seaweed (Ascophyllum nodosum) on fecal shedding of Escherichia coli O157:H7 by feedlot cattle and on growth performance of lambs

Thirty-two steers orally inoculated with a four-strain mixture (10¹⁰ CFU) of nalidixic acid-resistant Escherichia coli O157:H7 had sun-dried Ascophyllum nodosum seaweed (Tasco-14™) added to their barley-based diet (860 g/kg barley grain and 90 g/kg whole crop barley silage, dry matter basis) to assess its effectiveness in reducing fecal shedding of the pathogen. Steers were housed in four groups of eight and received Tasco-14™ in the diet, in place of barley, at levels (as fed) of 10 g/kg for 14 days (T1-14), 20 g/kg for 7 days (T2-7), 20 g/kg for 14 days (T2-14), or not at all (i.e., control, CON). The dietary treatments commenced 7 days after E. coli O157:H7 inoculation and fecal shedding patterns were examined over 14 weeks. Water, water–trough interface, feed and fecal pat samples were also collected weekly and cultured for E. coli O157:H7. Detection of the pathogen in fecal samples was less frequent (P<0.05) in T1-14 (99/168) and T2-7 (84/168) versus CON (135/168) and T2-14 (115/168), and the concentrations of E. coli O157:H7 recovered in feces from T1-14 and T2-7 steers were lower (P<0.005) than from CON or T2-14 steers. Rates of decline in shedding of E. coli O157:H7 were similar among treatments, but final numbers of E. coli O157:H7 were lower (P<0.05) in T1-14 and T2-7 as compared to T2-14 and CON. Fecal volatile fatty acid concentrations and pH were similar among treatments, suggesting no fecal alterations that were antagonistic to survival. E. coli O157:H7 was present in 1 (from T2-7) of 56 cattle drinking water samples, 2 of 56 (T1-14, CON) feed samples and 32 of 56 fecal pats. A second experiment investigated effects of the dietary treatment on growth performance of non-inoculated sheep. Tasco-14™ was administered to 40 individually fed Canadian Arcott lambs beginning at day 56 of a 105-day finishing period. The lambs received Tasco-14™ at 0 g/kg (control, CON), at 10 g/kg for 14 days (T1-14), 20 g/kg for 14 days (T2-14), 10 g/kg for 28 days (T1-28) or at 20 g/kg for 7 days (T2-7) as a top-dress on their pelleted, barley grain-based diet (n = 8). E. coli O157:H7 was not isolated from fecal samples collected at 4-week intervals, but generic E. coli populations were lower (P<0.05) in T1-28 lambs than in other treatments. Average daily gain, feed intake, feed efficiency and carcass traits did not differ among treatments. Our challenge study supports past studies showing that Tasco-14™ decreases shedding of E. coli O157:H7 by cattle. The lamb study shows that this additive did not directly affect feed intake or animal growth.     

The effect of high and low dietary crude protein and inulin supplementation on nutrient digestibility, nitrogen excretion, intestinal microflora and manure ammonia emissions from finisher pigs

A 2 × 2 factorial experiment was performed to investigate the interaction between a high- and low-crude-protein (CP) diet (200 v. 140 g/kg) and inulin supplementation (0 v. 12.5 g/kg) on nutrient digestibility, nitrogen (N) excretion, intestinal microflora, volatile fatty acid (VFA) concentration and manure ammonia emissions from 24 boars (n = 6, 74.0 kg live weight). The diets were formulated to contain similar concentrations of digestible energy and lysine. Pigs offered the high-CP diets had a higher excretion of urinary N (P < 0.001), faecal N (P < 0.01) and total N (P < 0.001) than the pigs offered the low-CP diets. Inulin supplementation increased faecal N excretion (P < 0.05) and decreased the urine N : faeces N ratio (P < 0.05) compared with the inulin-free diets. There was no effect (P > 0.05) of dietary treatment on N retention. There was an interaction (P < 0.05) between dietary CP concentration and inulin supplementation on caecal Enterobacteria spp. Pigs offered the diet containing 200 g/kg of CP plus inulin decreased the population of Enterobacteria spp. compared to those with the inulin-supplemented 140 g/kg CP diet. However, CP level had no significant effect on the population of Enterobacteria spp. in the unsupplemented diets. Inulin supplementation increased caecal Bifidobacteria (P < 0.01) compared with the inulin-free diets. There was no effect of inulin supplementation on VFA concentration or intestinal pH (P > 0.05). Pigs offered the 200 g/kg CP diets had higher (P < 0.05) manure ammonia emissions from 0 to 240 h of storage than pigs offered the 140 g/kg CP. In conclusion, inulin supplementation resulted in an increase in Bifidobacteria concentration and a reduction in Enterobacteria spp. at the high CP level indicating that inulin has the ability to beneficially manipulate gut microflora in a proteolytic environment.     

复合微生态制剂对断奶仔猪生产性能、粪便菌群及血液指标的影响

目的 探讨复合微生态制剂对断奶仔猪生长性能、粪便乳酸菌和大肠埃希菌数、血液红胞数以及血红蛋白含量及其对免疫水平的影响.方法 选择25日龄的断奶仔猪共108头,平均分为两组:Ⅰ组和Ⅱ组,每组3个重复,每个重复18只,Ⅰ组饲喂全价料+2.0‰复合微生态制剂;Ⅱ组为对照组,饲喂全价料,实验期为42 d.结果 至实验结束时,复合微生态制剂组的料重比显著低于对照组(P ＜0.05);14、28和42 d时复合微生态制剂组粪便中的大肠埃希菌数比对照组低7.94％,2.90％和4.89％,与对照组相比差异有统计学意义(P＜0.05);14d时,复合微生态制剂组粪便乳酸菌数与对照组相比差异有统计学意义(P＜0.05),28和42 d时,两组粪便乳酸菌数差异无统计学意义(P＞0.05).14、28和42 d时复合微生态制剂组血液中红细胞数和血红蛋白浓度均显著高于对照组.两组血清尿素氮水平差异无统计学意义(P＞0.05),复合微生态制剂组血清总蛋白和IgG的含量与对照组相比有升高的趋势,但差异无统计学意义(P＞0.05),复合微生态制剂组血清IgA和IgM的浓度显著高于对照组(P＜0.05).结论 复合微生态制剂可以显著降低断奶仔猪的料重比,降低粪便中大肠埃希菌数量,促进血液红细胞和血红蛋白的含量,提高断奶仔猪的免疫水平.     

产酶益生素对肉鸭生长性能及肠道菌群的影响

目的产酶益生素对肉鸭生产性能及肠道菌群的影响,为开发利用产酶益生素提供理论依据。方法选用1日龄120只樱桃谷肉鸭,随机分为4组,每组30只,设2个重复,每重复15只,对照组I饲喂基础日粮,实验II、III和IV组分别在基础日粮中添加0.1%、0.2%和0.3%产酶益生素,测定肉鸭的生长性能及肠道菌群数量。结果与对照组相比,实验II、III和IV组平均日增重分别提高了5.82%、11.50%和12.60%,日均采食量分别提高了0.85%、1.71%和3.78%,料重比分别降低了4.85%、8.81%和7.93%;盲肠内双歧杆菌的数量分别提高了3.29%、9.86%和9.48%,乳酸杆菌分别提高了5.49%、10.98%和12.56%,大肠埃希菌分别降低了11.88%、16.35%和22.48%。结论产酶益生素能提高肉鸭的生产性能,促进肠道双歧杆菌及乳酸杆菌的增殖,降低大肠埃希菌的数量。     

Effects of Saccharomyces cerevisiae supplementation on ruminal parameters, nutrient digestibility and growth in sheep: A meta-analysis

Despite the increased use of dry active Saccharomyces cerevisiae yeast supplementation in ruminant feeding, inconsistent results among studies hamper the prediction of its effects on animal performance. A meta-analysis has been conducted to quantify the magnitude of yeast supplementation effects on ruminal parameters, total tract nutrient digestibility, growth and feed conversion across different studies with sheep. Different methodologies and small numbers of studies necessitated the use of the classical effect size method, in which a unitless standardised effect size (Hedges's g) was used to calculate differences obtained in outcomes between supplemented and non-supplemented sheep. Summary statistics across studies were calculated with fixed and random effects models, whereas subgroup-analysis and meta-regression were applied to identify possible interfering factors that could be responsible for between-study variability. Possible publication bias was evaluated with graphical and statistical tests. Effect sizes for ruminal ammonia nitrogen (33 comparisons), pH (42 comparisons) and total volatile fatty acids (38 comparison) did not (P > 0.10) present heterogeneity among studies, and was not affected by yeast supplementation. No effects (P > 0.05) were detected on the stoichiometry of volatile fatty acids or protozoa counts. Effects sizes calculated for digestibility of dry matter, organic matter, crude protein, acid-detergent fibre and neutral-detergent fibre, which included from 17 to 28 comparisons, showed considerable (>50%) between-study variability. This variability could not effectively be explained by the categorical variables (1) mode of yeast application, (2) feed intake (ad lib versus restricted) or (3) faeces collection method, or the continuous independent variables (1) adaptation period, (2) study period, (3) dietary roughage concentration and (4) dietary crude protein concentration. According to random effects models, digestibility of dry matter, organic matter and crude protein were increased by yeast supplementation, with no effects found for digestibility of fibre components. Substantial unexplained between-study variability (50–90%) was found for growth (13 comparisons) and feed intake (9 comparisons). This meta-analysis presented evidence that addition of dry active S. cerevisiae yeast to diets did not have any effect on growth, feed conversion, ruminal parameters or fibre digestibility in sheep.     

Effect of diets on growth,digestibility, carcass and meat quality characteristics of four rabbit breeds

The current study was conducted to evaluate three diets using four rabbit breeds. A total of 320 male weaned rabbits representing four breeds named V-line, Saudi-1, Saudi-2 and Saudi-3 were randomly distributed into three comparable dietary treatments. Three levels of indigenous feedstuffs (IFS) of 42.5%, 65% or 87.5% (alfalfa hay, barley and wheat bran) were substituted for the same levels of non-indigenous feedstuffs in the diet (corn grain, soybean, molasses, and limestone) to form three diets named D1, D2 and D3, respectively. These dietary treatments were used to evaluate post-weaning growth performance, feed intake, feed conversion, carcass and lean composition, and nutrients digestibility in four rabbit breeds.Partial replacement of IFS with non-indigenous feedstuffs attained significant increase in growth performance. The diet containing 87.5% IFS led to significant increase in daily weight gains by 8.4, 4.0, 8.1, 6.2 and 6.7 g at age intervals of 5–6, 7–8, 9–10, 10–11 and 11–12 weeks compared to the control diet, respectively. The diet containing 87.5% IFS showed a significant reduction in feed conversion ratio compared to control diet during the experimental periods. The diet containing 65% IFS showed significant increases in pre-slaughter weight (112 g) and hot carcass weight (89 g), while dressing percent, offal weight and percent, and non-carcass weights and percentages (head, fur, legs + tail, viscera) were not significantly different. The diet containing 87.5% IFS gave an increase of 1.1%, 6.4%, 8.8%, 17.9%, 7.4%, and 19.6% in digestibility coefficients of organic matter (OM), crude protein (CP), neutral detergent fibre (NFD), acid detergent fiber (ADF), hemi-cellulose (HC) and cellulose (C) compared to control diet, respectively.Feed intakes were moderate and ranged from 69 to 124 g for V-line, 77 to 128 g for Saudi-1, 79 to 130 g for Saudi-2, and 76 to 119 g for Saudi-3 along with moderate ratios of feed conversion ranging from 2.65 to 3.80, 2.45 to 3.90, 2.46 to 3.79 and 2.63 to 3.65, respectively. Pre-slaughter weight, hot carcass weight, and offal weight were in favour of Saudi-2 rabbits compared to the other groups. Both Saudi-1 and Saudi-2 rabbits were slightly higher than Saudi-3 in weights and percentages of head, fur, viscera and legs + tail. Lean and bone weights and percentages and meat to bone ratio in Saudi-2 carcasses were slightly higher than those recorded in the other groups, while moisture, DM, CP, EE and ash contents in the lean have shown little differences between groups. Rabbits of Saudi-1 were ranked the first in digestibility coefficients of OM, CP, NDF, ADF, HC, C and cell count compared to other groups.Rabbits of Saudi-2 fed diet containing 87.5% IFS recorded the heaviest body weights and gains since this class showed considerable deviations in body weights of 345, 341, 269, 307, 321, 345 and 347 g at 6, 7, 8, 9, 10, 11 and 12 weeks of age, respectively, in comparison with the lightest class. Both Saudi-2 and Saudi-3 rabbits fed the diet containing 87.5% IFS had favourable estimates of feed conversions ranging from 2.1 to 3.4, while rabbits of Saudi-1 fed the diet containing 87.5% IFS recorded the best digestibility coefficients.     

Phylogeny of Caragana (Fabaceae) based on DNA sequence data from rbcL, trnS–trnG, and ITS

Phylogenetic relationships of 48 species of Caragana (Fabaceae: tribe Hedysareae) and one representative each of Astragalus, Calophaca, Halimodendron, and Hedysarum are estimated from DNA sequences of the rbcL gene, trnS–trnG intron and spacer, and ITS region. At least one representative of all five sections and 12 series within Caragana are included. Analyses yielded strongly supported clades corresponding to sections Caragana, Bracteolatae, and Frutescentes. The species of section Jubatae are distributed among three strongly supported clades, i.e., one with the species of section Bracteolatae, another with two species of section Spinosae, and a third as sister to section Frutescentes. All but the last of these six clades are corroborated by at least one unambiguously traced morphological character. The placement of the other four species of section Spinosae are not well supported and lack unambiguous morphological synapomorphies, and the samples of Calophaca and Halimodendron nest within Caragana with weak support.     

Effect of compensatory growth on performance, carcass composition and plasma IGF-1 in grower finisher pigs

A total of 48 female pigs (Large White × Landrace × Duroc cross) were used to determine whether a compensatory feed regime influenced performance, carcass composition and the level of plasma IGF-1. Pigs of initial age 73 days were fed a commercial diet at 0.70 of ad libitum (R) for 40 days followed by a return to ad libitum feeding for a further 42 days. The control group was fed ad libitum (A) throughout. Groups of animals on R and A feed regimes were slaughtered at the end of restriction period (SL1), 2 days after refeeding ad libitum (SL2) to establish the more immediate effects of refeeding on IGF levels, and after 42 days refeeding (SL3; n = 8 for each group). As expected, during the restriction period, average daily live weight gain in all the slaughter groups of R pigs was significantly lower than A pigs (P < 0.01); there was no significant difference in feed conversion ratios. In the re-alimentation period of SL3, R pigs grew 12.9% faster (P = 0.033), indicating compensatory growth. At SL1, there was a trend for carcass weight (P = 0.108) of A pigs to be higher than R pigs, but at SL2 live weight and carcass weight of A pigs were significantly heavier than R pigs (P < 0.05), but not at SL3. For killing-out percentage, there was no difference in SL1. After refeeding for 2 days (SL2) and 42 days (SL3), R pigs had significantly lower killing-out percentage than A pigs (P < 0.05). As a proportion of live weight, R pigs had smaller heart, kidney and liver (P < 0.05) than A pigs at SL1. At SL2, only the kidney was smaller in the restricted group (P < 0.05) and there were no significant differences in SL3. As a proportion of carcass weight, Longissimus dorsi was heavier in the R pigs at SL1 (P = 0.108) and SL2 (P < 0.05), but not at SL3. At SL1, there was a trend for intramuscular fat of A pigs to be higher than R pigs. The plasma IGF-1 level was lower in R pigs than A pigs (P = 0.010) at SL1, and slightly lower at SL2 (P = 0.110), with no significant differences at SL3. Dietary restriction period influenced plasma IGF-1 levels, which returned to the ad libitum group levels when animals were refed, as did live weight and carcass weight. It appears that the internal organs and possibly fat, but not muscles, underwent a compensatory response when animals were refed.     

水环境中重金属铜对异育银鲫肠道微生物的影响

【目的】了解水环境中重金属铜对异育银鲫肠道微生物组成及多样性的影响。【方法】采用试剂盒提取异育银鲫肠道总DNA,然后对总DNA进行16S r RNA进行扩增,构建异育银鲫肠道微生物16S r RNA基因克隆文库,最后进行数据分析。【结果】厚壁菌门、变形菌门和拟杆菌门为异育银鲫肠道中主要的细菌类群,在不同浓度的重金属铜胁迫处理后,厚壁菌门的含量明显降低。稀释性曲线、Venn图和多样性指数分析结果表明,重金属铜胁迫处理后异育银鲫肠道微生物多样性明显降低。【结论】重金属铜会使异育银鲫肠道微生物组成及多样性降低。此结果为研究重金属污染对异育银鲫健康状况的影响及异育银鲫养殖过程中病害的诊断奠定基础。     

甲维盐对斜纹夜蛾幼虫肠道细菌的影响

【目的】斜纹夜蛾幼虫属杂食性、高食量的害虫,通过分子生物学手段对经甲维盐处理后的斜纹夜蛾幼虫肠道微生物进行比对,研究肠道共生菌群受毒剂刺激后的代谢变化,探讨菌株的自身代谢与甲维盐的作用受体的相关性。【方法】基于Illumina MiSeq技术测序平台,对取食甲维盐和未取食甲维盐的斜纹夜蛾幼虫中肠细菌的16S rRNA可变区进行高通量测序,分析对比细菌群落结构多样性。【结果】肠杆菌属、根瘤菌属在斜纹夜蛾的肠道中占优势地位,经过甲维盐处理后两者的丰度大幅下降。沙雷氏菌属和黄单胞杆菌属在处理后减少到几乎为零,相反,原先不占据优势的棒状杆菌属和甲醇杆菌属,处理后丰度明显上升。【结论】甲维盐处理后的优势菌群以及丰富度均发生变化,表明斜纹夜蛾的肠道菌群结构可能与甲维盐毒理机制有关。     

Effect of temperature on development, growth and feeding of Coccinella septempunctata and Hippodamia convergens reared on the tobacco aphid, Myzus persicae nicotianae

Preimaginal development, mortality, aphid consumption rate, and size and weight upon reaching the adult stage of the aphidophagous coccinellids Hippodamia convergens Guérin-Méneville and Coccinella septempunctata L. collected from Karditsa, central Greece, were examined at four constant temperatures (14, 17, 20 and 23 °C) and L16:D8. The coccinellids fed on the tobacco aphid, Myzus persicae nicotianae Blackman. Egg, larval and pupal mortality was highest at 14 °C reaching 85.0, 73.8 and 29.4% in H. convergens and 49.3, 75.4 and 58.8% in C. septempunctata, respectively. Total preimaginal development ranged from 57.2 to 70.4 days at 14 °C, and to 16.9 and 22.1 days at 23 °C in H. convergens and C. septempunctata, respectively. Heavier and larger adults of H. convergens were obtained at 17 and 20 ° C. In C. septempunctata temperature did not affect adult weight while the lowest size was observed at 14 and 17 °C. Day-degrees requirements for preimaginal development in H. corvengens were 212.9 above a developmental threshold of 11.0 °C. The corresponding values for C. septempunctata were 281.5 and 10.7 °C. In H. convergens total and daily aphid consumption ranged from 46.8 aphids at 14 °C to 85.0 aphids at 23 °C and from 1.5 aphids at 14 °C to 9.2 aphids at 23 °C, respectively. The corresponding values for C. septempunctata were 112.0 and 2.7 at 14 °C and 157.7 and 12.4 at 23 °C. The results show the high potential of both predators as biological control agents against the tobacco aphid. The knowledge obtained could be essential for their appropriate use and for the improvement of mass rearing systems.     

屎肠球菌对斑节对虾肠道代谢组学及炎性因子的影响

【背景】屎肠球菌(Enterococcus faecium)作为乳酸菌属的潜在益生菌,因其具有良好的生物学特性在动物养殖中应用广泛,但是屎肠球菌对肠道代谢组学的研究很少。【目的】以斑节对虾为试验动物,初步探究屎肠球菌R8对肠道代谢组学及炎性因子的影响,为屎肠球菌作为益生菌在对虾养殖中的应用提供理论基础。【方法】将400条斑节对虾随机分配,设计饲料中屎肠球菌添加量分别为107、108、109 CFU/g的3个试验组,不添加屎肠球菌为对照组进行试验,养殖周期为28 d。养殖周期结束后测定斑节对虾免疫球蛋白M (immunoglobulin M,IgM)、对虾酚氧化酶(phenoloxidase,PO)、白介素6 (interleukin 6,IL-6)、补体片段3a (complement fragment 3a,C3a)的活性含量并运用LC-MS代谢组学研究肠道内源代谢物的变化,分析差异代谢物和相关的代谢通路。【结果】添加屎肠球菌对斑节对虾炎性因子有积极的影响,增加了斑节对虾体内免疫球蛋白IgM、对虾酚氧化酶、补体片段3a的含量,降低了其体内IL-6的含量,对肠道差异代谢物的分析发现,对...     

内生真菌与苍术粉对连作花生根际微生物区系和微量元素的影响

通过盆栽试验,研究了内生真菌拟茎点霉B3(Phomopsis liquidambari)及苍术(Atractylodes lancea)粉联合施用对连作花生根际土壤微生物区系、酶活性及有效态微量元素(Mo、B、DTPA-Fe、Zn、Cu、Mn)含量的影响。结果表明:内生真菌B3和苍术粉复合处理比内生真菌B3处理的荚果和秸秆产量分别增加10.28%和14.11%,内生真菌B3处理与正常施肥相比显著提高了根瘤数量、荚果和秸秆产重,各处理组与正常施肥对照相比分枝数和根长无显著差异。B3处理与对照相比显著提高了种子期、结荚期和成熟期根际土壤可培养细菌和放线菌数量,B3和苍术粉复合处理与对照相比显著提高种子期、花期和成熟期可培养真菌和放线菌数量;细菌DGGE指纹图谱聚类分析表明,B3和苍术粉复合处理相对于正常施肥处理,显著改变种子期、苗期、花期和成熟期花生根际土壤细菌群落结构,同时苗期、花期和结荚期的细菌条带数和香农指数也有所提高,真菌DGGE指纹图谱聚类分析表明,B3和苍术粉复合处理对真菌群落影响较大,除种子期以外的生育期真菌条带数和香农指数都有明显提高,花期真菌群落结构变化最大,相似度仅为49.6%。花生关键生育期(花期和结荚期)根际土壤脲酶和蔗糖酶活性B3处理和复合处理都显著高于正常施肥对照,促进了连作花生生态系统的物质循环和能量流动。B3和苍术粉复合处理促进了花生生长发育必需微量元素Mo、B、Fe、Zn、Mn的活化,花生叶片和籽粒中微量元素Mo、B、Fe的积累显著增加。研究结果表明,内生真菌和苍术粉联合施用能有效改善连作花生根际微生物区系,提高土壤酶活性,促进微量元素的活化和吸收,对缓解花生连作障碍具有重要意义。     

Ceriopsins A–D, diterpenoids from Ceriops decandra

Chemical examination of the ethyl acetate solubles of the CH₃OH:CH₂Cl₂ (1:1) extract of the roots of Ceriops decandra collected from Kauvery estuary resulted in the isolation of four new diterpenoids, ceriopsins A–D (1–4). The structures of the new diterpenoids were elucidated by a study of their physical and spectral data as methyl 17-hydroxy-16-oxobeyeran-18-oate (1), methyl 16(R)-16,17-dihydroxybeyeran-18-oate (2), 1β,15(S)-isopimar-7-ene-1,15,16-triol (3), and 8,15(R)-epoxypimarane-1β,16-diol (4).     

原产地和入侵地紫茎泽兰对泽兰实蝇的选择性、卵巢蛋白质含量与解毒酶活性的影响

[目的] 紫茎泽兰是我国危害严重的恶性入侵杂草。比较专一性天敌泽兰实蝇对该杂草入侵前后植株的适应性,是揭示外来植物入侵后适应性机制的重要科学问题之一。[方法] 比较泽兰实蝇对原产地和入侵地紫茎泽兰植株的寄主选择性,并测定寄生于2类植株的上泽兰实蝇卵巢蛋白质含量及乙酰胆碱酯酶、羧酸酯酶、谷胱甘肽S-转移酶活性。[结果] 泽兰实蝇对原产地和入侵地紫茎泽兰的选择无显著性差异;寄生在紫茎泽兰入侵地植株上的卵巢蛋白质含量较原产地植株上更高。解毒酶活力比较表明,入侵地紫茎泽兰上泽兰实蝇的羧酸酯酶活性低于原产地上的,但谷胱甘肽S-转移酶（雌虫）活性比较则相反,乙酰胆碱酯酶活性比较均无显著性差异。[结论] 紫茎泽兰入侵后,专一性天敌泽兰实蝇的适应性有所下降,丰富了外来植物入侵机制中天敌逃逸假说的内涵。     

Effect on prolactin secretion of Echinacea purpurea, Hypericum perforatum and Eleutherococcus senticosus

It has been recently reported that prolactin (PRL) plays an important role in immune system regulation. In this study we investigated the activity of three natural drugs with immunomodulatory activity: Echinacea purpurea (EP), Hypericum perforatum (HP) and Eleutherococcus senticosus (ES) on PRL production. Male rats were orally treated with two different doses (30 and 100 mg/kg) of extract of these drugs for 3 or 15 days. A 3-day treatment was not able to modify PRL serum levels, whereas a 15-day treatment with EP and HP at the higher dose significantly inhibits PRL production. A treatment with ES was always ineffective. A possible mechanism for this effect could be that both HP and EP extracts display a direct dopaminergic activity, although an involvement of the GABA-ergic system cannot be excluded.     

Effect of herbivory by Teleonemia scrupulosa on the performance of Longitarsus bethae on their shared host, Lantana camara

Herbivory by insects may change the characteristics of nutrients and secondary plant chemicals of the foliage, thereby altering the acceptability and suitability of the plant for oviposition, feeding and development for subsequent herbivores. In the current study, the effect of herbivory by the sap-sucking lace bug, Teleonemia scrupulosa Stäl (Heteroptera: Tingidae), on the suitability of Lantana camara L. (Verbenaceae) for the root-feeding flea beetle, Longitarsus bethae Savini & Escalona (Chrysomelidae: Alticinae), was investigated under laboratory conditions. Preference of adult L. bethae was not influenced by the intensity of feeding damage caused by T. scrupulosa adults. However, high densities of T. scrupulosa nymphs and their feeding damage caused L. bethae adults to emigrate and colonize less infested or uninfested plants. Oviposition by L. bethae was significantly reduced at high densities of T. scrupulosa nymphs. While low infestation of T. scrupulosa had no effect the survival of L. bethae, moderate and high infestations caused significant reduction in percentage survival of L. bethae. The number of T. scrupulosa nymphs was negatively correlated with the percentage survival of L. bethae. Neither the duration of development nor the body size of L. bethae was influenced by the intensity of T. scrupulosa infestation. Overall, undamaged or slightly damaged plants that allowed better survival of L. bethae were often chosen as oviposition sites in preference to those that were highly infested, and on which survival was poor. Although the present study indicates the likelihood of inter-specific competition between L. bethae larvae and T. scrupulosa, this is likely to be mitigated by female flea beetles choosing to oviposit on less infested or uninfested plants in the field.     

Antagonism of Aeromonas hydrophila by propolis and its effect on the performance of Nile tilapia, Oreochromis niloticus

Propolis, a resinous substance collected by Apis mellifera bees from various plant sources and mixed with secreted beeswax, is a multifunctional material used by bees in the construction, maintenance, and protection of their hives. The collected propolis sample, from High Egypt, was dark-green with olive-odor. The minimal inhibition concentration (MIC) of propolis-ethanolic-extract, against Aeromonas hydrophila, was 80 μg Propolis-ethanolic-extract and crude propolis (1%) were added to artificial basal diet with (30% crude protein) to evaluate their efficacy on the fish growth-performance, immunostimulation and resistance to A. hydrophila. Two hundred and twenty-five Oreochromis niloticus (8 ± 0.45 g/fish) were divided into three equal treatments (T) of triplet replicates. The fish of T₁ were fed on basal diet (control). The fish of T₂ were given the basal diet, containing propolis-ethanolic-extract. The fish of T₃ were given the basal diet containing crude propolis for 28 day. The fish were intraperitoneally challenged by A. hydrophila (0.2 × 10⁷ cells ml⁻¹) at the end of the feeding period and kept for 15 more days.The best growth rate and feed conversion ratio were obtained with T_2. The increase in the average daily gain, specific growth rate and feed efficiency ratio were highly significances in T₂ followed by T₃ when compared with the control group. The HCT-level and monocyte-counts were increased (T₂). No significant change, in the large lymphocytic-count was found among the three treatments (28–27–28%), while the neutrophil-count was significantly decreased (7%) with T₂ and increased (13.11%) with the control. A significant increase in serum lysozyme and serum bactericidal activities was found with T₂. The RLP against A. hydrophila was high with T₂ and T₃.The propolis-ethanolic-extract enhanced the growth, immunity and resistance of O. niloticus against A. hydrophila more than the crude propolis.