Dietary supplementation of sodium butyrate may benefit growth performance and intestinal function in juvenile grass carp (Ctenopharyngodon idellus)

A 49‐days feeding trial was conducted to study the effects of sodium butyrate on growth performance, gut morphology of juvenile grass carp. Five isoenergetic and isonitrogenous experimental diets were compounded by the supplementation in the basal diet with gradient sodium butyrate at 0, 500, 1000, 2000, 3000 mg kg^?1 respectively. A total of 375 juvenile grass carp (with initial body weight of 3.8 g) were randomly allocated into five diet treatments, and each treatment has three replicates. The results showed that the specific growth rate (SGR) of SB1000 and SB2000 group was significantly higher (P < 0.05) than that of the other groups. Moreover, the lowest SGR was observed in SB3000 group. Feeding rate and the whole‐body proximate composition including moisture, crude lipid, crude protein and crude ash were not affected by sodium butyrate (P > 0.05). Total superoxide dismutase activities in hepatopancreas in the experimental groups were significantly higher than those in the control group (P < 0.05). Glutathione peroxidase activity in hepatopancreas was significantly upregulated by dietary sodium butyrate level (P < 0.05). However, the activity of total antioxidant capacity and the contents of malondialdehyde were not significantly different among groups. The expression levels of mRNA encoding PepT1 and LAT2 in the foregut both showed a first increasing and then decreasing tendency as dietary sodium butyrate level increased (P < 0.05), and peaked in SB1000 and SB2000 groups respectively. The results indicated that appropriate dietary supplementation of sodium butyrate at 2000 mg kg^?1 could improve the growth, antioxidant ability and intestinal absorption capacity of the juvenile grass carp.     

鲤肠道sglt1基因的表达与抗体制备

钠/葡萄糖共转运载体1(sodium/glucose cotransporter 1,Sglt1)是协助葡萄糖吸收的主要蛋白。实验首先采用RT-PCR获取sglt1基因全长,克隆至PGME-T载体进行序列及免疫原性分析,选择长度为92个氨基酸(544～637)的多肽作为目的片段(sglt1-P)),扩增sglt1-P,引入双酶切位点EcoRⅠ和HindⅢ后,连接至pET-32a(+)上,构建表达载体pET-32a(+)-sglt1-P,转化至E.coli Rosetta中,获得重组基因工程菌,通过IPTG诱导表达,获得目标多肽,并以此为抗原制备Sglt1特异性抗体。SDS-PAGE电泳分析表明,目标多肽分子量约为30 ku。采用耳缘静脉结合皮下注射,免疫新西兰长耳兔,免疫总时长为38 d。制备了鲤Sglt1抗体,ELISA测得效价为1∶105;免疫组化结果表明,抗体具有较高亲和力和特异性,可以应用于鲤Sglt1的表达定位研究。该抗体的获得为鲤肠道Sglt1表达及转运活性的系统研究奠定了基础,同时,获取的Sglt1抗体亦可用于其它鱼类Sglt1转运蛋白表达定位和定量研究。     

磺胺间甲氧嘧啶钠对厚颌鲂幼鱼SOD活性和MDA含量的影响

以(30±2.3)g/尾的厚颌鲂(Megalobrama pellegrini)幼鱼为研究对象,采用一次性胸腔注射法,通过观察磺胺间甲氧嘧啶钠对厚颌鲂幼鱼超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量的影响,探讨磺胺间甲氧嘧啶钠对厚颌鲂幼鱼各组织酶活性的影响变化及其休药期。结果显示,在同一浓度下,随着给药时间的延长,肝脏、肌肉和鳃组织SOD活性出现先降后升再降的趋势,而随着浓度的增加,则出现先升后降的趋势;肝脏、肌肉和鳃组织MDA,随着给药时间的延长和浓度的增加,均出现先升后降的趋势;厚颌鲂各组织SOD和MDA受磺胺间甲氧嘧啶钠影响最小的是肌肉,其次是鳃、肝脏;通过SOD和MDA变化情况,确定休药期为28 d左右。     

Functional partition of cells in the gill epithelium of the Japanese eel, Anguilla japonica, and the role of hormones

Viable chloride and pavement cells were isolated from the gill epithelium of Japanese eel, Anguilla japonica, by a 3-step percoll gradient centrifugation at low speed. Viability of the isolated cells were tested by the trypan blue exclusion test, rhodamine-123, or pre-labelling the cells with fluo-3 Ca²⁺ dye and examined by laser confocal microscopy. Isolated chloride cells responded to ionomycin with a rapid increase in Ca²⁺ fluorescence, which was abolished by chelating external Ca²⁺ with EGTA. Peptide hormones, including arginine vasotocin, isotocin, insulin-like growth factor I and II, and urotensin I increased Ca²⁺ entry, urotensin II had no effect, and eel corpuscles of Stannius extract reduced residual Ca²⁺ fluorescence. Isolated chloride cells and pavement cells from eels were analyzed for their enzymatic activities involved in intermediary and nitrogen metabolism. Chloride cells had high levels of glutaminase I, glutamate dehydrogenase, glutamate oxalacetate transaminase, HCO₃-ATPase and carbamoyl phosphate synthetase II. Pavement cells had highly active glucose-6-phosphate dehydrogenase and AMP deaminase. Both had high levels of lactate dehydrogenase compared with other tissues.     

Cobia Rachycentron canadum L. reared in low‐salinity water: does dietary sodium chloride affect growth and osmoregulation?

The effects of NaCl supplementation (0.0%, 2.5%, 5.0%, 7.5% and 10.0% dry weight of a basal diet) on growth, gill histological alterations and osmoregulation of juvenile cobia reared in low‐salinity water (5 g L^?1) were assessed. At the end of the experiment, gills were sampled for Na⁺, K⁺‐ATPase activity determination and histological evaluation. In all treatments, no mortality was observed. Results showed that dietary NaCl supplementation did not alter growth. At the highest supplementations (7.5% and 10.0%), juvenile cobia showed higher feed intake and feed conversion ratio. Na⁺, K⁺‐ATPase activity was higher in fish fed the diet without salt supplementation than in those fed with NaCl‐supplemented diets. The number of chloride cells significantly increased with increasing dietary salt level, being 2.5‐fold higher in fish fed with 10.0% NaCl supplementation (41 cells mm^?2) than in those from the non‐supplemented fed group (16 cells mm^?2). These findings indicate that dietary salt supplementation stimulated chloride cell proliferation paralleled with a reduction in the gill Na⁺, K⁺‐ATPase activity, suggesting a possible decrease in energy consumption associated with osmoregulation. However, the suggested energy sparing did not have a significant impact on juvenile cobia growth.     

盐度变化对斜带石斑鱼生理生化因子的影响

采用生化分析方法研究了盐度变化(24、14、4及对照34)对斜带石斑鱼幼鱼(体重19.59?0.25g)相关生理生化因子的影响,在盐度处理后1 d、3 d、6 d和9 d取样并检测鳃丝Na /K -ATP酶、血清中血糖、天门冬氨酸氨基转移酶(AST)、溶菌酶,肝脏超氧化物歧化酶(SOD)含量及H.E染色观察鳃丝氯细胞的变化。结果显示：各盐度试验组斜带石斑鱼幼鱼的Na /K -ATP酶活性变化基本一致,均在第3 d达到最高值,随后下降,至第6 d达到稳定。鳃丝氯细胞数量在盐度24试验组中变化不大,在盐度14试验组中则略有减少,在盐度4试验组中鳃丝氯细胞6 d后出现变化,氯细胞数量减少,胞核较大,H.E染色较深,细胞处于较原始的状态。各盐度试验组斜带石斑鱼幼鱼的血糖水平变化趋势相一致,均在第6 d到达峰值,随后呈下降趋势。AST水平在盐度24、盐度4试验组随时间的延长呈上升趋势,在第9 d后到达各自的最高值,盐度14试验组则呈现持续下降趋势。SOD活性随时间的延长呈现先降低后上升的趋势,在第3 d时各试验组达最小值,但试验组间SOD活性差异显著 (P＜0.05)。溶菌酶活性随时间的延长呈上升趋势,试验组在第6 d达到的峰值,随后下降并趋于稳定,试验组间差异显著(P＜0.05)。结果表明,斜带石斑鱼幼鱼通过盐度驯养,由盐度34水体逐渐淡化至盐度为24、14、4的水体中,能较快适应盐度低至4的水环境。本研究为低盐度地区淡化养殖石斑鱼提供依据。     

利用食盐替代物柠檬酸钠制作日本方头鱼盐干品的品质

近年来,随着全球减盐行动的推进,人们对低盐饮食的健康需求日益增长,具备良好风味和外观的低钠盐食品已成为当前的研究热点之一。为适应消费者对健康饮食的需求,本研究利用柠檬酸钠作为食盐替代物制作盐干品,对其品质进行了调查研究。本研究以日本方头鱼为原料,用9%(W/V,质量浓度)食盐(对照组)和柠檬酸钠(实验组)浸渍后风干,制作了高水分半干制品,对表皮颜色和pH值,鱼肉中的Na+浓度、质地、鲜味特征物质IMP、新鲜度指标K值,以及烤制后的感官评价开展了品质研究。结果显示,实验组盐干品表皮红色色度值a*、彩度值C*和pH值显著高于对照组;其肌肉组织中Na+浓度为对照组的39%,且具有较高的持水力,较低的断裂荷重和断裂应力,断裂变形显著高于对照组;同时,IMP和K值等品质指标没有显著差异。烤制后的感官评价结果验证了以上结果,实验组的咸味评分显著低于对照组,在外观评分略高的基础上,咀嚼性、鲜味和总体可接受性等方面没有显著差异。研究表明,用柠檬酸钠代替食盐制作日本方头鱼盐干品,在保证品质的同时,可有效提升表皮色彩,降低Na+含量,是理想的钠盐替代物之一,可为水产品干制加工的工艺改善、口味调节、减少钠盐用量等提供新的思路。     

矮壮素对高羊茅的生长及内源激素含量的影响

用200、600、1000、1400和1800μg&#183;g^-1的矮壮素喷施高羊茅,结果显示,矮壮素改变了高羊茅的生长格局,使植株生长速率降低,根系变短,单株分蘖出现一定程度的增多,其中以600和1000μg&#183;g^-1的矮壮素处理较为经济有效。600μg&#183;g^-1的矮壮素处理后的21d内,高羊茅叶片内源激素IAA与GA（1/3）含量一直呈下降趋势,ABA含量呈上升趋势,ABA／IAA、ABA／GA（1/3）比值较处理初期分别提高了2．12倍和1．77倍。内源激素含量与比例的变化可能是引起高羊茅生长格局改变的重要原因。     

包膜丁酸钠对脂多糖刺激下断奶羔羊血清炎性细胞因子、肠道通透性及肠道组织形态的影响

本试验旨在研究包膜丁酸钠(CSB)对脂多糖(LPS)刺激下断奶羔羊血清炎性细胞因子、肠道通透性及肠道组织形态的影响.试验选取(42±1)日龄、平均体重为(11.79±0.54)kg的断奶羔羊24只,按体重相近原则随机分为4组:空白组(CON组)、LPS组、CSB2L组、CSB3L组,其中CON和LPS组饲喂基础饲粮,C...     

竞争性特异等位基因PCR检测山东甜菜夜蛾对高效氯氰菊酯的抗性

为明确山东地区甜菜夜蛾对高效氯氰菊酯抗性水平,采用竞争性特异等位基因PCR方法,检测甜菜夜蛾钠离子通道基因片段上L1014F的突变频率.结果表明,敏感种群个体中均未发现突变个体;田间章丘种群92％个体具有L1014F突变,其中64％为L1014F突变纯合子,28％为L1014F突变杂合子.经高效氯氰菊酯汰选5代后的抗性种群检测个体中均未发现敏感型纯合子.安丘种群的L1014F突变等位基因频率最高,为85％,泰安、滕州和滨州种群分别为50％、43.33％和30％,相关性分析表明甜菜夜蛾L1014F突变等位基因频率与对高效氯氰菊酯不敏感度呈线性正相关(Y=1.106x +0.079,R2 =0.93).