养殖水体中水质净化菌的筛选和鉴定

通过富集培养的方法,从养殖水体和淤泥中筛选出4株优良的水质净化菌.各菌株经鉴定分别为假单胞菌属(Pseudomonas)、凝结芽孢杆菌(Bacillus coagulans)、黄色节杆菌(Arthrobacter flavescens)、坚强芽孢杆菌(Bacillus firmus).它们对模拟养殖水体中高达5mg/L的氨态氮和亚硝态氮的降解率均能达到80%和90%以上,其中假单胞菌属还具有反硝化作用.     

三种光合细菌不同生态环境下的生长试验

本试验以光合细菌中的沼泽红假单胞菌(Rhodopseudomonas palustris)、球形红假单胞菌(Rhodopseudomonas sphaeroides)、荚膜红假单胞菌(Rhodopseudomonas capsulata)为试验对象，分别比较三株光合细菌在不同温度、盐度、pH生态环境下的生长差异。试验结果表明：①球形红假单胞菌为广盐性菌种，荚膜红假单胞菌适宜在高盐度水中生长，沼泽红假单胞菌则适宜在低盐度水中生长。②沼泽红假单胞菌生长受pH影响较大，适宜在培养基初始pH值较低的水中生长，随着pH的升高，生长速度下降；球形红假单胞菌和荚膜红假单胞菌则适宜在各种pH水环境中生长。③三种光合细菌相对适宜在25～30℃之间生长。因此在盐碱地水产养殖过程中，对于高pH、高碳酸盐碱度的盐碱水质中可选用荚膜红假单胞菌，而在离子比例失调和水型复杂的盐碱水质可选用广盐性的球形红假单胞菌。     

复合微生物制剂对水质因子降解效果初探

微生物为芽孢杆菌、光合细菌、铜绿假单胞菌,研究了3菌株不同比例及浓度的混合物对养殖水体中CODMn、NH3-N、NO2--N等水质因子的控制和处理效果。复合制剂对几种水质因子有较好的降解效果,温度、作用时间等对微生物降解效果有一定影响。     

地衣芽孢杆菌降解水产养殖中残余饵料的特性研究

从土壤及饲料添加剂中筛选获得了一株能较高效降解水产养殖中残余饵料蛋白、淀粉的功能菌,经鉴定为地衣芽孢杆菌.通过研究养殖水体中饲料浓度、pH值、温度等因素对地衣芽孢杆菌降解饲料中蛋白质、淀粉的影响.结果表明,该菌降解饲料中蛋白质、淀粉的适宜条件为:饲料浓度≤5g/L,pH值6～7,温度25～30℃,盐浓度0～1%,溶氧浓度约4mg/L.地衣芽孢杆菌在这种水体生态条件下接种5%,饲料中的蛋白质与淀粉降解率约为60%.     

小球藻与芽孢杆菌对对虾养殖水质调控作用的研究

通过在凡纳滨对虾养殖水体中添加小球藻和芽孢杆菌,研究其对养殖水质的调控作用。结果表明,小球藻和芽孢杆菌联合处理组对水质的调控效果优于只添加芽孢杆菌组或小球藻组。菌-藻联合处理组能很好地降低水体中氮、磷的含量,对氨氮的作用尤为明显;实验进行的第5天内,NH4 -N含量显著低于对照组(P<0·05),降低率为32·94%,NO2--N降低率为10·29%,PO34--P降低率为36·02%。小球藻 芽孢杆菌组NH4 -N含量平均为0·277mg/L,日均积累速率0·0135mg/L·d,而对照组为0·0472mg/L·d;NO2--N平均含量为0·334mg/L,日均积累速率为0·0617mg/L·d。小球藻在调控水质的同时也向水体释放有机物,从而引起水体COD的上升。     

3种细菌对小球藻生长和脱氮除磷效率的影响

鉴于水资源日益紧缺且水污染问题日渐加剧的现状,藻菌共生系统作为一种节能环保的污水处理方式,有助于提高污水处理效率。通过人工模拟城市污水,选取3种污水处理中常用细菌地衣芽孢杆菌(Bacillus licheniformis)、枯草芽孢杆菌(Bacillus subtilis)和沼泽红假单胞菌(Rhodopseudomonas palustris)与小球藻构建藻菌共生系统,探究了不同细菌对蛋白核小球藻(Chlorella pyrenoidosa FACHB-5)生长以及污水脱氮除磷效率的影响。结果显示,在3种藻菌共生系统中,地衣芽孢杆菌为小球藻促生长菌,而枯草芽孢杆菌对小球藻生长有抑制作用,沼泽红假单胞菌对小球藻生长无显著影响(P>0.05),且沼泽红假单胞菌的生长受到小球藻的显著抑制(P<0.05)。在3个共生系统中,地衣芽孢杆菌-小球藻共生系统中小球藻生物量最高,第2天水体的总氮和总磷去除率分别达到79.84%和83.48%,显著高于小球藻单独培养试验组(P<0.05)。研究表明,3种藻菌共生系统中,细菌与微藻间的关系具有特异性,应选择适宜的促生菌与微藻共培养,合适的藻菌共生系统可提高水体总氮和总磷的去除率。     

三种微生物制剂对有机物废水中氨氮及亚硝酸盐的影响

实验采用复合净水菌、复合芽孢杆菌、光合细菌与空白对照比较了三种微生物制剂对有机物废水中氨氮及亚硝酸盐的处理效果。结果显示：清除氨氮方面：利用微生态制剂微生物制剂净化7d,三种微生物制剂对有机物污染水体中氨氮的清除率均极显著大于对照组（P〈0.01）,处理组之间复合芽孢杆菌的氨氮降解率56.58%,显著大于降解率分别为42.64%和44.02%的复合净水菌和光合细菌组（0.01〈P〈0.05）。清除亚硝酸盐方面：三种微生物制剂对亚硝酸的降解率均极显著大于对照组（P〈0.01）,而复合芽孢杆菌对亚硝酸的降解率68.84%,显著大于复合净水菌47.70%及光合细菌组37.17%（0.01〈P〈0.05）。结果表明：三种微生物制剂对有机物污染的水体中的氨氮及亚硝酸盐均具有降解效果,其中复合芽孢杆菌对于降低水体中氨氮和亚硝酸盐效果最佳。     

4种微生物制剂对凡纳滨对虾育苗水质及仔虾存活的影响

采用平板法测定标注为地衣芽孢杆菌、枯草芽孢杆菌、粪肠球菌和植物乳杆菌制剂的活菌密度,通过16S rRNA基因测序分析对其进行菌种鉴定。在盛水250 L的玻璃钢桶中投放凡纳滨对虾无特定病原的无节3期幼体5×10~4尾,各组由溞状Ⅰ初期至仔虾Ⅰ期,连续10 d,每日分别投菌制剂1次,地衣芽孢杆菌和枯草芽孢杆菌组每次投菌5×10~8 cfu/L,粪肠球菌和植物乳杆菌组每次投菌1×10~8 cfu/L,同时投放饵料,对照组始终不投菌制剂,定期测定水质并分析仔虾存活情况。试验结果显示,4种制剂均由密度高的单一菌种构成;地衣芽孢杆菌组水体氨氮、无机磷和化学需氧量均显著高于对照组,而在育苗早期粪肠球菌和植物乳杆菌组亚硝态氮含量显著降低(P0.05);除地衣芽孢杆菌组仔虾Ⅲ期存活率显著低于枯草芽孢杆菌组外,各组存活率间差异不显著(P0.05),但枯草芽孢杆菌组仔虾存活率和活力均表现最佳,而地衣芽孢杆菌组表现最差。可见,无明显胁迫条件下,连续投放微生物制剂对凡纳滨对虾育苗水质及仔虾存活率总体上无显著提高作用,但两种芽孢杆菌制剂的作用效果存在明显差异。     

高通量测序法分析两株益生菌对凡纳滨对虾肠道菌群结构的影响

为分析荚膜红细菌和蜡样芽孢杆菌2株益生菌对凡纳滨对虾肠道菌群结构的影响,本实验对凡纳滨对虾进行为期30 d的养殖饲喂实验,饲喂后期利用高通量测序凡纳滨对虾肠道微生物的16S rDNA V4区,来分析不同益生菌饲喂后凡纳滨对虾肠道菌群的结构特征,并结合对虾体质量增加率和攻毒后累计死亡率的宏观指标来进行分析。结果显示：①空白组（CK）、荚膜红细菌组（Rc）和蜡样芽孢杆菌组（Bc）样品OTU范围为374~506,其中CK组对虾肠道菌群OTU数量最低,饲喂益生菌后的2组对虾肠道菌群中OTU数量相对较高;②在门分类水平上,3组的变形菌门数均为最多,CK组主要为变形菌门和少量拟杆菌门,Bc组主要有变形菌门、拟杆菌门、无壁细菌门、厚壁细菌门和假单胞菌,Rc组主要是变形菌门、拟杆菌门、厚壁菌门、酸杆菌门、放线细菌、梭杆菌门和蓝细菌;③稀释曲线和Shannon指数结果可见,CK组样品物种丰度和复杂度最低,且Bc组样品丰度和复杂度相对较高;④PCA分析发现,Rc组和CK组样品微生物组成较为接近,结合宏观对虾体质量增加率和攻毒后累计死亡率的结果分析,可见相较于荚膜红细菌,蜡样芽孢杆菌对凡纳滨对虾肠道微生物菌群影响更显著,且益生效果更佳。研究表明,饲喂益生菌可以扩增对虾肠道微生物菌群丰度,并能抑制弧菌属等有害菌群的生长,提高对虾体质量增加率并降低死亡率,从而达到益生效果,其中以饲喂蜡样芽孢杆菌菌株效果更佳。     

光合细菌菌剂和沼泽红假单胞菌对实验水体氮磷营养盐和微生物群落的影响

为比较光合细菌菌剂与沼泽红假单胞菌(Rhodopseudomonas palustris)的生理生态特性,分析了不同初始菌量的菌剂PG和菌株PSB-1对实验水体氨氮(NH_4~+-N)、亚硝氮(NO_2~--N)、硝氮(NO_3~--N)和活性磷(PO_4~(3-)-P)的降解效果,通过高通量测序分析了菌剂PG的优势菌组成及实验结束时水体细菌数量和微生物群落组成。结果显示,菌剂PG组对实验水体的PO_4~(3-)-P、NO_3~--N和NO_2~--N有一定的降解作用,其最大降解率分别为40.98%、28.28%和20.12%。菌株PSB-1组仅对实验水体的NO_2~--N和PO_4~(3-)-P有一定的降解效果,其最大降解率分别为14.19%和9.88%。菌剂PG的主要优势菌为红假单胞菌属(Rhodopseudomonas sp.)。实验7 d后实验组水体细菌数量和微生物群落结构发生变化,水体细菌数量增长,形成以异养细菌为优势菌的菌群结构。结果表明光合细菌菌剂PG对水质因子的降解效果优于沼泽红假单胞菌PSB-1,但与报道的高效光合细菌菌株的降解能力存在一定差距。     

投喂频率对绿鳍马面鲀幼鱼生长和肌肉品质的影响

为研究不同投喂频率对绿鳍马面鲀幼鱼生长性能和肌肉品质的影响,在室内循环水养殖系统中,采用人工配合饲料,以1次/d、2次/d、3次/d、4次/d等4种投喂频率,对体质量(13.8±0.83)g的绿鳍马面鲀幼鱼进行了饲养试验,试验时长为42 d。结果显示,随着投喂频率增加,绿鳍马面鲀幼鱼的终末体质量呈逐渐升高的趋势,特定生长率呈先升后降的变化趋势,其中3次/d组幼鱼的特定生长率最高,显著高于1次/d组(P<0.05);饲料系数也随着投喂频率的增加而升高,3次/d组的饲料系数显著高于1次/d组(P<0.05),4次/d组的饲料系数显著高于1次/d组和2次/d组(P<0.05);肌肉品质方面,4次/d组幼鱼的肌肉粗脂肪含量显著高于1次/d组(P<0.05),不同投喂频率组间肌肉粗蛋白质含量和灰分含量无显著性差异(P<0.05)。综合考虑生长性能和肌肉品质指标,绿鳍马面鲀幼鱼适宜的投喂频率为日投3次。     

Effects of Bacillus preparations on immunity and antioxidant activities in grass carp (Ctenopharyngodon idellus)

This experiment was conducted to study the effects of Bacillus preparations on immunity and antioxidant activities in grass carp. A total of 315 grass carp, with similar initial weight (average weight of fish 45?g), were randomly divided into three groups with three replicates. The control group was fed the basal diet without Bacillus; treatment group 1 was added Bacillus preparation no. 1 with 1?×?10⁸?cfu/m³ per 7?days in culture water and also fed the basal diet; treatment group 2 was fed the basal diet mixed with 0.5?% Bacillus preparation no. 2, and the culture water was added 1?×?10⁸?cfu/m³ Bacillus preparation no. 1 per 7?days. After 4?weeks of culture, 12 grass carp from each replicate were taken randomly for the determination of immune response and oxidization resistance indices. The results showed that compared with control, the level of globulin and IgM of treatment group 2 was significantly increased (P?<?0.05), which was also significantly higher (P?<?0.05) than that of group 1. For the non-specific immunity index, compared with control, the lysozyme activity and complement (C3) content of treatment group 1 significantly increased (P?<?0.05), and the level of myeloperoxidase and C3 of treatment group 2 was significantly higher (P?<?0.05) than that of control, which was also significantly higher (P?<?0.05) than that of group 1. In the serum, compared with the control, the level of total antioxidant activity (T-AOC), antisuperoxide anion free radical (ASAFR) and glutathione (GSH) of two treatment groups was significantly increased (P?<?0.05); GSH content of treatment group 2 was significantly (P?<?0.05) higher than that of treatment group 1 and control. There was no significant difference between T-AOC and ASAFR among the two treatment groups; no significant effect was found on glutathione peroxidase (GSH-Px) and maleic dialdehyde (MDA) among the three groups. In the liver, T-AOC, SOD, ASAFR, GSH-Px and GSH from two treatment groups were significantly higher (P?<?0.05) than those of control; T-AOC, SOD and catalase from treatment group 2 were significantly higher (P?<?0.05) than those of treatment group 1; and MDA of two treatment groups was significantly decreased (P?<?0.05) as compared with the control. The results indicate that Bacillus preparations added into water can increase serum immunoglobulin levels and most of non-specific immune parameters content and enhance the antioxidant ability of grass carp, while adding Bacillus preparation into the water and feed is much better.     

Effect of feeding frequency on growth and food conversion of Cyprinus carpio fry

Cyprinus carpio fry (173 ± 38 mg) were fed 6 times a day, 3 times a day, 2 times a day, once a day, once in 2 days, once in 3 days or given no food at all for a total period of 21 days. Food consumption by the group fed 3 times a day was maximum (45.6 gcal^*/meal) and the level of consumption per meal was very low in the remaining groups.

Feeding rate increased to a maximum (598.2 gcal g⁻¹ day⁻¹) in fry fed 3 times a day; a further increase in feeding frequency reduced the feeding rate. Feeding frequency influenced all bioenergetic parameters except absorption efficiency which remained constant at 97.7%. Although the growth efficiency did not change significantly in the groups fed very frequently (2 times a day or more), the growth rate was maximum in the group fed 3 times a day. With regard to both feeding and growth, a feeding schedule of 3 times a day seemed to be optimum and was suggested for practical nursery culture of Cyprinus carpio.     

Effects of Black Cumin Oil (Nigella sativa) on Sensory,Chemical and Microbiological Properties of Rainbow Trout During 23 Days of Storage at 2 ± 1°C

In the present study, black cumin oil in the rates of 0.00 % (the control), 0.10 %, 0.40 %, 0.70 %, 1.00 % and 1.30% was added to rainbow trout feed for 144 days. After the feeding process, trout were harvested and stored at 2 ± 1°C in ice, and changes in chemical, microbiological, and sensory parameters were examined periodically. According to sensory analyses, black cumin oil used in fish meat did not cause a perceptible sensory change for all groups. Chemical analyses showed that the addition of black cumin oil to fish feed led to higher total volatile basic nitrogen content in the fish flesh. During the storage period, the highest peroxide values were observed in the groups with 1.0% and 1.3% black cumin oil added, and the lowest were in the groups with 0.0% and 0.1% added oil. The highest microbial count value was observed in the control group.     

Water quality and phytoplankton stability in response to application frequency of bioaugmentation agent in shrimp ponds

Splitting the recommended weekly dosage of bioaugmentation agent and applied at varying frequencies were tested to determine its effects on water quality and phytoplankton stability in tiger shrimp (Penaeus monodon) grow-out ponds. The supplier's recommended weekly dosage was followed but at varying application frequencies namely: once per week, twice per week, and four times per week for the duration of 120 culture days. A treatment with no bioaugmentation was added as control. Results showed that ammonia and particulate organic matter levels were significantly lower and plankton die-off was greatly minimized if the product was applied four times a week application compared with twice a week and weekly applications. Significant reduction in the number of luminous Vibrio species was observed in ponds with more frequent applications than those with less. For shrimp, survival and production were significantly higher in ponds with twice and four times per week applications compared to the weekly application and the control (P < 0.05). Results of this study indicate that splitting the weekly dosage of bioaugmentation agent and applying it four times per week is highly beneficial and ideal for shrimp culture.     

Application of Compensatory Growth to Enhance Production in Channel Catfish Ictalurus punctatus

Four treatment groups that received repeating cycles of fixed feed deprivation for either 0, 1, 2, or 3 d (control, treatment 1, treatment 2, and treatment 3, respectively), followed by periods of refeeding with a 36% protein commercial catfish feed once daily as long as the active phase of compensatory growth (CG) persisted, were assessed in flow-through aquaria. No-feed periods elicited the CG state and were immediately followed by days of ad libatum refeeding. At the end of 10 wk, average growth rate (AGR) of fish was higher ( P < 0.05) than the control by 40%, 180%, and 191% for treatment 1, treatment 2, and treatment 3, respectively. The average weight of fish in treatment 3 was heavier ( P < 0.05) than the average control group at the end of the study period. Mean daily feed consumption was 3.91%, 5.03%, 5.36%, and 5.98% for control, treatment 1, treatment 2, and treatment 3, respectively. Mean feed consumption per fish per day was 24%, 71.3%, and 70.7% higher than the control in treatment 1, treatment 2, and treatment 3, respectively. Restricted feeding is one of the effective methods to contain ESC-related losses in commercial channel catfish fingerling operations. The mean cumulative survival of treatment groups registered higher ( P < 0.05) survival to Edwardsiella ictaluri infection compared to the daily fed control fish. Results from this study show that compensatory growth response triggered by periodic non-feeding days can improve growth rate, feed consumption, and improved survival to ESC infections in channel catfish fingerlings.     

Effects of feeding frequency on the growth of young estuary grouper, Epinephelus tauvina (Forskål), cultured in floating net-cages

Studies on the effects of feeding frequency on the growth of young estuary groupers (Epinephelus tauvina) with initial size ranging from 16.2 to 16.9 cm in total length were conducted in floating net-cages. Seven feeding frequencies in the order of one feeding in 5 days, 4 days, 3 days, 2 days, 1 day, two feedings daily and three feedings daily were studied. Optimal growth and good food conversion ratio as well as higher survival rate were obtained in groups fed to satiation with one feeding in 2 days. Weight gains were substantially reduced in groups fed to satiation with one feeding in 5, 4 or 3 days and were not enhanced when the feeding frequencies were increased to two or three feedings daily. The fact that food conversion ratios were similar in fish fed to satiation with one feeding in 5, 4, 3 and 2 days suggests food intake to be important as a growth limiting factor. Total food intake per feeding was appreciably higher in fish fed once in 2 days. The intake of food was found to be closely related to the amount of food remaining in the stomach, intake being maximal when the stomach was empty. The food deprivation time in estuary groupers was found to be about 36 hours at which over 95% of the food was digested and less than 0.5% body weight of food remained in the stomach. Hence, feeding the fish at 48-hour intervals, i.e. once in 2 days, greatly enhanced maximum intake and efficient utilization of the food.     

柑桔皮粉作饲料添加剂对肉仔鸡生产性能影响的研究

将21日龄笼养京黄肉仔鸡180只随机分3组,再将每组60只鸡各分为3个重复（每个重复20只）。对照组只喂基础饲粮,在此基础上,两个试验组分别添加1.5％、2.5％柑桔皮粉,进行38d饲养试验。结果表明：只均增重试1组1.040kg、试2组1.125kg,分别比对照组（0．963kg）提高8.09％和16.9％,经F检验和多重比较与对照组间分利差异显著（P＜0.05）和极显著（P＜0.01）;科重比（耗料与活重之比）试1组2．55：1、试2组2．46：1,分别比对照组（2．77：1）降低耗料7.94％和11.17％;而每kg增重的饲料成本则分别比对照组减少0.58元和0．88元;两个试验组肉仔鸡成活率分别比对照组高3．3％、5．0％,只均增加收入分别比对照组多1．22元和2.37元,经济效益以试2组为最佳。     

Fillet texture and muscle structure in brown trout (Salmo trutta) subjected to long-term exercise

Brown trout (Salmo trutta) (2.7 g initial mean weight) were reared in freshwater for 8 months at water velocities of <0.1 (control group), 1 or 2 body lengths per second (BL s^?1) (exercise groups). Growth (body weight, body length and body width), muscle structure (muscle fibre diameter and width of myosepta) and flesh quality parameters (dry matter, muscle pH, collagen content and solubility, instrumental evaluation of texture) were measured at the end of the experiment. The body weight of fish at 1 BL s^?1 was 22% higher than the control group. Muscle development was stimulated at 1 and 2 BL s^?1, leading to a higher condition factor, greater body height and width, and muscle fibre hypertrophy (55 vs. 59.5 μm fibre diameter in the control and 2 BL s^?1 groups respectively). Connective tissue and collagen were only slightly affected by exercise (no difference in collagen solubility, but a greater proportion of γ trimer and fewer α chains in the control compared with the exercised group). Flesh quality was affected, with greater dry matter content and lower post‐mortem pH in the 1 BL s^?1 group compared with the control and 2 BL s^?1 groups. The mechanical resistance of the raw fillets was slightly but significantly increased by exercise. The exercise‐related changes in muscle structure and texture are discussed.     

Effect of gonadotropin hormonal stimulation on out-of-season propagation success of different year classes of indoor-reared pikeperch (Sander lucioperca (L.))

Three trials of hormonally induced out-of-season spawning of cultured pikeperch were performed. Two preparations containing human chorionic gonadotropin (hCG) (groups Bg-4 and Pl-4) were applied in experiment I. Injections of preparations containing hCG either alone (group P1-3) or in combination with pregnant mare serum gonadotropin (PMSG) of different producers (groups Sr-3 and Pg-3) were applied in experiment II. Spawning effectiveness was determined for four age groups (2+ to 5+) of pikeperch stimulated with hCG (groups Pl-2–Pl-5) in experiment III. The females from all the experimental groups were stimulated once with a single dose of hormone at 300 IU kg^?1 body weight (BW). Females from the control group were injected with a 0.9 % solution of NaCl (group C). The working fecundity (CF; % of BW), latency time (LaT; h), and eyed-egg survival (EES, %) were determined. No progress in oocyte maturation was noted among the females from group C. Significant differences were noted in LaT, which was lower in group Pl-3 than in groups Sr-3 and Pg-3. The youngest fish (2+) matured significantly more slowly and exhibited significantly lower values of the CF and EES indexes in comparison with older fish (LaT 102 vs 75–80 h; CF 5.4 vs 10.4–11.2 % BW; EES 47 vs 70–77 %). The hormonal preparations used had a positive impact on the ovulation and spermiation of the cultured pikeperch. No improvement in the effectiveness of out-of-season spawning was noted when combined preparations of hCG and PMSG were used.