Impacts of dietary supplementation of bamboo vinegar and charcoal powder on growth performance,intestinal morphology,and gut microflora of large-scale loach Paramisgurnus dabryanus

Although accumulating data demonstrate that dietary supplementation of bamboo vinegar and charcoal powder(BVC)can significantly strengthen the immunity and boost the growth of domestic animals,its application potency still awaits verification in commercial fish species such as the large-scale loach Paramisgurnus dabryanus.The impacts of 90-day dietary supplementation of 1%and 2%BVC on survival and growth performance of the loach,and on the intestinal morphological characteristics and gut microflora were analyzed.Our data show that the large-scale loach supplied with BVC at the experimental doses had significant higher survival rates and better growth performance(indicated by greater weight gain(1.13–1.14 times),higher specific growth rate(1.04 times),and lower feed conversion ratio(0.88–0.89 times))compared to that of the control(P<0.05).Histological examination revealed significant longer villus(3.22–5.54 times),deeper crypt(1.77–1.87 times),and thicker muscle(1.59–3.17 times)in the intestines of large-scale loach fed with BVC(P<0.05).Furthermore,we found that the gut microflora consisted of significantly fewer proportions of potential pathogenic bacterial species(Aeromonas veronii and Escherichia coli),but significantly greater proportions of beneficial microbes(Lactococus raffinolactis and Faecalibacterium prausnitzii).Therefore,dietary intake of BVC can promote intestinal tract development and optimize gut microflora,by which the survival and growth of large-scale loach may be improved.

Effects of different protein and lipid levels on the growth performance and intestinal microflora of loach(Paramisgurnus dabryanus)

The aim of this study was to examine the effects of dietary protein and lipid levels on the growth per-formance and homeostasis of the intestinal flora in Paramisgurnus dabryanus.An 8-week 3×3 two-factorial experiment was conducted to investigate the interaction between dietary crude protein(CP:30%,35%,40%)and ether extract(EE:6%,10%,14%)on the growth rate and the intestinal microflora of P.dabryanus.A total of 2,160 fish(5.19±0.01 g)were randomly allotted to 36 aquariums each with 60 fish.Fish were fed the experimental diet twice daily.Results revealed that weight gain rate(WGR),specific growth rate(SGR),protein efficiency ratio and net protein utilization significantly increased when increasing protein levels from 30%to 40%(P<0.05).Both WGR and SGR enhanced first but reduced thereafter with maximum value at 10%lipid level as dietary lipid increased from 6%to 14%(P<0.05).Significant interactions between protein and lipid were found with feed conversion rate,lipid efficiency ratio and net lipid utilization(P<0.05).At the phylum level,Proteobacteria and Actinobacteria were the dominant bacteria;at the genus level,Burkholderia-Caballeronia-Paraburkholderia was the dominant bacteria.Fish fed the diet containing 10%lipid had a higher abundance of Proteobacteria and unclassi-fied_f_Eenterobacteriaceae than those fed the 14%lipid diet,and a higher abundance of Rhodobacter than those fed the 6%lipid diet(P<0.05).Analysis of the predicted functions showed that metabolism in the intestine of fish in the CP40EE10 group was more active than that in CP30EE14 group.Polynomial regression analysis found that a diet containing 40.87%protein and 9.88%lipid can be considered optimal for P.dabryanus.

三种常用稻田农药对大鳞副泥鳅的急性毒性研究

为研究吡蚜酮、稻杰和二甲四氯钠三种常用稻田农药对大鳞副泥鳅(Paramisgurnus dabryanus)急性毒性的影响,选择体长约2.74 cm、体重约5.57 g的大鳞副泥鳅作为受试对象,分别采用40 mg/L、80 mg/L、180 mg/L、280 mg/L和380 mg/L药物浓度进行急性毒性试验。结果显示,吡蚜酮的安全浓度最高,二甲四氯钠次之,稻杰最低,而三者的96 h半致死浓度分别为280 mg/L、8 mg/L和90 mg/L,安全浓度分别为28 mg/L、0.8 mg/L和9 mg/L。研究结果表明,大鳞副泥鳅对这3种农药都表现出较高的敏感性,其敏感性依次为稻杰>二甲四氯钠>吡蚜酮。该研究为稻田养殖大鳞副泥鳅过程中的农药使用浓度提供了理论基础。

干旱胁迫对大鳞副泥鳅免疫指标的影响

为探究气呼吸型鱼类在养殖运输中常遭遇的短时干旱胁迫对其免疫应答的影响,本实验以大鳞副泥鳅(Paramisgurnus dabryanus)为研究对象,将其暴露于空气中12、24、48、72、96 h后检测血清和肝脏免疫指标的变化。结果显示:空气暴露显著增加了大鳞副泥鳅血清总蛋白、白蛋白、球蛋白和免疫球蛋白M含量,但对血清和肝脏溶菌酶活性无显著影响。补体C3和补体C4含量均呈先升后降的变化趋势。血清热休克蛋白70和热休克蛋白90含量在暴露48 h分别升高至基础水平的3.3倍和2.0倍。血清炎症细胞因子水平随着暴露时间的延长呈现先升后降的趋势;空气暴露12 h,肝脏肿瘤坏死因子-α和白细胞介素-1β上升至基础水平的1.4倍,白细胞介素-6和白细胞介素-12上升至1.5倍。上升的免疫指标表明短期(0~48 h)的干旱胁迫对大鳞副泥鳅有明显的免疫刺激作用,随后多数免疫指标在实验后期(48~96 h)下降,表明持续的干旱胁迫导致免疫刺激转为免疫抑制作用。

大鳞副泥鳅皮肤抗氧化酶活性的昼夜节律研究

昼夜节律是生物生理学研究重点,用以揭示物种特有的活动规律。该试验首次以大鳞副泥鳅(Paramisgurnus dabryanus)为研究对象,探究其皮肤抗氧化酶活性的昼夜节律变化。将300尾泥鳅随机分成三组,暂养阶段结束后,取皮肤组织检测各种抗氧化酶活性。试验结果表明,大鳞副泥鳅皮肤组织的总抗氧化能力(T-AOC)、超氧化物歧化酶(T-SOD)、谷胱甘肽转移酶(GST)和谷胱甘肽过氧化物酶(GSH-Px)活性的峰值都出现在夜晚,过氧化氢酶的活性峰值出现在08:00。同时,丙二醛的峰值出现在12:00,谷值出现在04:00,差异性显著(P<0.05)。研究发现,大鳞副泥鳅皮肤组织的抗氧化酶活性呈现明显的昼夜节律,并且在夜晚具有较高的抗氧化能力。

三苯基锡和聚苯乙烯微塑料联合暴露对大鳞副泥鳅的急性毒性效应

以大鳞副泥鳅(Paramisgurnus dabryanus)为受试生物,三苯基锡和聚苯乙烯微塑料(R=200 nm)为染毒物质,进行三苯基锡单独暴露以及与聚苯乙烯微塑料联合暴露的毒性试验,揭示三苯基锡对大鳞副泥鳅的急性毒性效应规律以及聚苯乙烯微塑料对三苯基锡急性毒性的调节作用。在水温(20.0±1.0)℃、溶氧充足(≥6.5 mg/L)条件下,采用半静态水生生物急性毒性实验方法,根据预实验结果设置6个浓度组(0.01、0.016、0.024、0.037、0.058和0.09 mg/L)和一个空白对照组,聚苯乙烯微塑料浓度为1 mg/L。结果显示,三苯基锡单独暴露对大鳞副泥鳅的24、48、72和96 h的半致死浓度(LC50)分别为0.086、0.037、0.026和0.019 mg/L,安全浓度(SC)为0.002 mg/L,药物蓄积程度系数(MAC)随实验时间延长呈较快下降趋势。三苯基锡与聚苯乙烯微塑料联合暴露实验结果表明,中高浓度组(0.037、0.058 mg/L)100%的死亡率较三苯基锡单一毒性结果均有延迟,而高浓度组(0.09 mg/L)无显著变化,表明聚苯乙烯微塑料对三苯基锡的急性毒性具有延缓作用且存在浓度阈值。

野生和养殖大鳞副泥鳅营养成分比较分析

对野生和养殖大鳞副泥鳅(Paramisgurnus dabryanus)营养成分分别进行了测定。结果表明,野生大鳞副泥鳅水分、灰分、脂肪、蛋白质的含量分别为77.30%、1.30%、1.10%、18.10%,养殖大鳞副泥鳅分别为71.80%、1.10%、5.30%、17.20%;18种氨基酸总量野生为17.40%、养殖为15.50%,色氨酸、苯丙氨酸和甘氨酸于养殖个体中稍高于野生个体,其他15种氨基酸均以野生个体的含量稍高;人体必需氨基酸和鲜味氨基酸含量均以野生个体的略高,分别为8.03%和6.47%,养殖个体的分别为6.84%和6.02%;野生和养殖大鳞副泥鳅的不饱和脂肪酸分别占脂肪酸总量的67.13%、77.39%,其中多不饱和脂肪酸分别为27.39%和41.65%,DHA+EPA分别占脂肪酸总量的4.20%和1.59%。

稻田常用农药对台湾泥鳅的急性毒性比较试验

在水温为(25.3±2.4)℃条件下,采用静水试验法,进行了四种稻田常用农药(虱螨脲、甲氨基阿维菌素苯甲酸盐、氰氟草酯和五氟磺草胺)对体质量为(16.2±0.6)g的台湾泥鳅(Paramisgurnus dabryanus spp.)幼鱼的急性毒性试验。结果显示:四种试验药物对台湾泥鳅幼鱼的96 h半致死浓度和安全质量浓度分别为:虱螨脲(712.7 mg/L,168.7 mg/L)、甲维盐(39.4 mg/L,12.3 mg/L)、氰氟草酯(26.1 mg/L,11.0 mg/L)、五氟磺草胺(25.2 mg/L,9.3 mg/L)。四种试验药物毒性大小依次为五氟磺草胺>氰氟草酯>甲维盐>虱螨脲。试验结果表明,四种农药安全质量浓度均高于日常用量,可安全使用。

Piezoelectric Immunoasay of Thyroidal Triiodothyronine

Using the primers which specially amplify the conservative motif of Human SRY gene, we studied the PCR amplification of Sox genes in genomic DNA of two species of mud loach: Misgurnus anguillicaudatus and Paramisgurnus dabryanus. Four bands with the length of 200,550,940 and 1000 bp respectively, were presented in the PCR products of Misgurnus anguillicaudatus. Three bands with the length of 200,550 and 900 bp were presented in that of Paramisgurnus dabryanus. Southern blotting results indicated that the 200 and 550 bp bands are specially positive. There is no difference between male and female individuals as well as between these two species.