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1.
Fish intestinal microbiota changes with the diet and this effect is of particular interest considering the increasing substitution of fish meal by plant protein sources. The objective of this work was to study the effects of partial substitution of fish meal with lupin and rapeseed meals on gut microbiota of the gilthead sea bream (Sparus aurata) and in goldfish (Carassius auratus). Faecal, gastrointestinal and intestinal contents were characterized using culture-based and molecular methods. Vibrionaceae was high in faeces and in the intestine of sea bream, while a more diverse microbiota was retrieved from the stomach, where Bacillales and Flavobacteriaceae appeared to be influenced by the diet. PCR-denaturing gradient gel electrophoresis profiles revealed a high diversity of the microbiota transiting in the sea bream digestive tract, with a shift between gastric and intestinal communities, especially in the group fed with lupin meal. The goldfish was different, with a predominance of Aeromonas spp., Shewanella putrefaciens and Staphylococcus spp. among the aerotolerant-cultivable bacteria. The culture-independent methods revealed the presence of anaerobes like Cetobacterium somerae, and that of Vibrio spp., likely in a viable, but noncultivable state. There was a trend towards decreasing diversity in goldfish microbiota with the partial substitution by lupin, which seemed to inhibit some taxa.  相似文献   

2.
Counts of Escherichia coli, faecal streptococci and enterococci were made on faecal specimens from human and animal origin and urban raw sewage waters, with microtiter plates containing selective substances. Escherichia coli was more numerous than faecal streptococci and enterococci in 80% of the samples regardless of the origin. Consequently the use of the ratio E. coli/faecal streptococci to distinguish human from animal origin of faecal pollution is questionable. Enterococcus faecalis was predominant in human and poultry faeces, Streptococcus bovis was typical of the bovine faeces and to a lesser extent also of pig faeces whereas Enterococcus durans, Ent. hirae and Ent. faecium did not characterize any faecal source. Streptococcus bovis could be distinguished in the microtiter plate by its inability to reduce triphenyl tetrazolium chloride (TTC) in the medium.  相似文献   

3.
Counts of Escherichia coli , faecal streptococci and enterococci were made on faecal specimens from human and animal origin and urban raw sewage waters, with microtiter plates containing selective substances. Escherichia coli was more numerous than faecal streptococci and enterococci in 80% of the samples regardless of the origin. Consequently the use of the ratio E. coli /faecal streptococci to distinguish human from animal origin of faecal pollution is questionable. Enterococcus faecalis was predominant in human and poultry faeces, Streptococcus bovis was typical of the bovine faeces and to a lesser extent also of pig faeces whereas Enterococcus durans, Ent. hirae and Ent. faecium did not characterize any faecal source. Streptococcus bovis could be distinguished in the mictrotiter plate by its inability to reduce triphenyl tetrazolium chloride (TTC) in the medium.  相似文献   

4.
Previous studies have shown that Menhaden fish meal, a common ingredient of animal feeds, is frequently contaminated with salmonellae. Animals that eat contaminated feed may become infected. If they, in turn, are eaten by humans, they may be a means by which salmonellae are introduced into the human population. Epidemiological studies of the fish-meal industry were carried out to determine the sources of salmonellae in fish meal and the factors affecting the persistence and survival of salmonellae during the processing of fish meal. Examination of 190 fish immediately after they came from the Gulf of Mexico revealed no salmonellae, but salmonellae were frequently isolated from samples of fish taken from the boats when they arrived at the plants. Salmonellae were also frequently isolated from dockside water at each of the plants. Approximately 50% of the samples taken in the raw fish processing areas were contaminated with salmonellae. The percentage of samples yielding salmonellae decreased progressively through the various sequences of processing, but more than 15% of the samples taken from the finished products were also positive. Salmonellae were isolated from the raw area of the plant most frequently while the plant was operating and less frequently when the plant was idle, whereas in the processing area of the plant the reverse was true. Salmonellae appeared to survive and multiply in the processing area of the plant while the plant was idle, which resulted in contamination of the first portion of each day's production. Salmonellae in the processed fish meal were reduced to nondetectable levels by reprocessing the first 45 min of each day's production.  相似文献   

5.
The extent of the environmental impact of an aquaculture development is mainly dependent on husbandry, feeding technique, feed composition and site selection. Feed composition, digestibility and feed conversion coefficient are of paramount importance for the level of discharge of wastes derived from fish farming. These determine the release of nutrients (e.g. phosphorus and nitrogen) and organic material. Excretion products (in particular waste feed and faeces) may cause changes in the ecosystem. However, the overall environmental load derived from aquaculture is comparatively small when compared to other waste loads from communities, industries, agriculture and forestry. The amount of phosphorus and nitrogen in feeds has decreased to 1 % and 7%, respectively, while feed conversion efficiency due to high energy feeds has improved to values around 1.2 in most salmon farming operations. This has greatly reduced overall environmental loads, which are presently calculated with 10 kg phosphorus and 60 kg nitrogen per tonne of fish produced. The organic wastes per tonne produced are presently estimated to reach 2500 kg wet weight per tonne live weight fish. System design and site selection are additional important considerations which influence greatly the level of environmental impact. The advantage of land-based systems over water-based systems is the fact that water treatment of effluents is possible in such systems, thereby greatly reduction total loads to receiving waters. The paper mainly focusses on nutritional aspects of environmental load.  相似文献   

6.
Results of experiments carried out on the tilapiine fish Oreochromis aureus (Steindachner) to evaluate the method used in the determination of the apparent dry matter and nutrient digestibilities of an ingredient, together with validity of estimations based on day and night collection of faeces, and internal and external markers, are presented. The apparent dry matter and protein digestibilities of the test diets were linearly correlated to the percent substitution of the test ingredient, percent fibre and ash in the test diets (P less than 0.05); the correlation coefficient for the individual relationships decreased in that order. Dry matter or protein digestibilities were not correlated to the dietary protein content (P greater than 0.05). Similarly there were no statistical differences between digestibility estimations based on faecal material, voided in the day or the night; and estimated using different markers viz crude fibre and Cr2O3. The apparent dry matter and protein digestibilities of the test ingredients, leaf meal, were curvilinearly related to the percent substitution of the ingredient in the test diets. The ingredient digestibilities estimated, using crude fibre as the marker, were consistently higher than those estimated with Cr2O3 (P less than 0.05). The present study suggests that, for ingredient digestibility estimations, test diets prepared by mixing 15-20% of the ingredient to a reference diet would be more desirable.  相似文献   

7.
The objective of the experiments was to study the suitability of using a faecal suspension of sheep for the estimation of the utilizable crude protein (uCP) of feeds for sheep by an in vitro incubation. Twenty-four single feeds and eight feed mixtures were used as incubation substrates. In Experiment 1, the gas production after the in vitro incubation with rumen fluid or with a faecal suspension of a sheep were compared using the Hohenheim gas test. It was found that there were significant linear regression between the 24, 48 and 72 h gas production with rumen fluid and those with faecal suspensions of 35, 50, 100 and 150 g wet faeces of sheep (which were 18.6, 23.5, 52.0 and 70.5 g faeces DM, respectively) per litre McDougall's buffer (P < 0.0001). The highest regression coefficient (r2) was calculated between the gas production after inoculation with a suspension of 100 g wet faeces per litre McDougall's buffer (x, ml x 200 mg (-1) feed DM) for 48 h and the gas production after inoculation with rumen fluid (y, ml x 200 mg (-1) feed DM) for 24 h: y = 0.82 (+/- 0.07)x + 9.87 (+/-3.83), r2 = 0.82, n = 32, P < 0.0001. Based on these results, in Experiment 2 the estimation of utilizable crude protein (uCP) of feeds was compared by using the in vitro incubation technique of Zhao and Lebzien (2000), where feeds were inoculated either with rumen fluid or with a faecal suspension (100 g wet faeces of sheep, i.e. 52 g faeces DM per litre McDougall's buffer). The results indicated that there were no significant differences of the estimated uCP after inoculation with rumen fluid or the faecal suspension (P > 0.05). A significant regression was found between the uCP after incubation for 48 h with 100 g wet faeces (x, g x kg (-1) DM) and the uCP after incubation for 24 h with rumen fluid (y, g x kg(-1) DM): y = 0.95 (+/-0.10)x - 4.90 (+/-26.70), r2 = 0.75, n = 32, Although this regression was significant, the coefficient r2 was not high. Therefore, further research is needed before sheep faeces could replace rumen fluid as an inocula for the estimation of uCP by the in vitro incubation technique.  相似文献   

8.
The present study determined the settling velocity and leaching rates of carbon and nitrogen from the faecal matter of Atlantic salmon (Salmo salar L.) fed two commercial diets, high energy (HE) and standard, in three separate experiments (December, March and May) which coincided with winter, spring and summer. Faecal settling velocities for individual samples were in the range of 3.7–9.2 cm s?1. There were significant differences (P < 0.05) in settling velocities among the three experiments, with lowest velocities measured in faecal samples collected in winter and highest velocities measured in samples collected in summer. There were no significant differences (P > 0.05) in faecal settling velocity among fish fed the different diet types. Faecal nutrient content in the different treatment groups prior to leaching was 269–318 mg g?1 for carbon and 28–37 mg g?1 for nitrogen. Both carbon and nitrogen contents were higher in faeces from fish fed the standard diet than in fish fed the HE diet (P < 0.05). Thus the use of HE diets resulted in a 12% reduction in faecal carbon content and an 8% reduction in faecal nitrogen when compared with standard diets. There were no consistent differences in faecal carbon among samples collected during the three experiments; however, significant differences in faecal nitrogen content were detected in samples collected on the three different occasions. Leaching of faecal carbon and faecal nitrogen ranged between 4–14% and 9–16% of the original amount, respectively, after 2.5‐min immersion in sea water, although there was no further significant (P > 0.05) leaching after this time. No significant difference in nutrient leaching rate was found in faeces of fish fed HE and standard diets, and no significant differences in leaching rates were apparent among samples collected at different times of the year. These values suggest there may be an overestimation by dispersion models of the amount of nutrients entering seabed sediments. The amount of nutrients leaching from faeces may also have an important role in nutrient flux in the water column.  相似文献   

9.
本实验评价了饲料中豆粕替代鱼粉蛋白后对异育银鲫的生长、饲料利用、氮代谢和鱼体免疫力等的影响。实验设计4种等氮等能的饲料,每种3个重复,分别以豆粕替代饲料中鱼粉蛋白的0%(对照,D1)、20%(D2)、80%(D3)和100%(D4)。实验在半循环水养殖系统持续16周,鱼的初重约2.32g,实验期间水温23-30℃。结果表明,随着饲料中豆粕含量的升高,摄食率显著升高(P<0.05),特定生长率、饲料转化效率、蛋白沉积率和能量沉积率显著降低(P<0.05);蛋白表观消化率显著升高,干物质和能量表观消化率则显著降低(P<0.05);总氮摄入量、表观氮摄入量、粪氮排出量、非粪氮排泄量、总氮沉积率均随着饲料中豆粕含量的升高呈显著降低到的趋势(P< 0.05),生产每千克鱼的氮排放量则随着饲料中豆粕含量的升高显著升高(P< 0.05);血清葡萄糖和甘油三酯的含量显著升高,而胆固醇的含量显著降低(P<0.05);血清的溶菌酶显著降低,超氧化物岐化酶逐渐升高(P<0.05)。  相似文献   

10.
Two different feeds in the initial period of adaptation of glass eels (Anguilla anguilla) to artificial food were examined. The difference between the experimental groups lay in the protein source: that of group A consisted of 50% fish meal and 50% chicken meal, and that of group B of fish meal alone. The mean weight of Gr. A was higher than that of Gr. B at the end of the experiment, and the percentage of larger elvers was higher (29%) than in group B (26%). It is concluded that 50% of the fish meal can be replaced by chicken meal, which is much cheaper in Israel and may also produce a slightly higher yield.  相似文献   

11.
The effects of moist extrusion processing of diets containing fish meal (FM) and conventional defatted soybean meal (SBM) or untoasted defatted soybean meal (white flakes [WF]) on amino acid composition, trypsin inhibitor activity (TIA), and apparent total tract digestibility of nutrients were studied. Three diets with the nutritional characteristics of feeds for salmonid fish were formulated: one control based on FM as protein source and two others where 40% of total amino acids from FM were substituted by either SBM or WF. Each diet was fed to mink either as an unextruded mixture of the ingredients or as extruded pellets in order to determine the effect of extrusion processing. Extrusion did not change the amino acid composition of the diets significantly, but reduced the TIA of both diets containing soy products by approximately 76%. Intake of the unextruded WF diet was only one-third compared with the other diets. The dry matter concentration in faeces from mink fed diets containing soy products was significantly lower than in mink fed the FM diet. Digestibility of crude protein, all amino acids and fat was lower, but starch higher, in the unextruded WF diet than in the FM and SBM diets, whereas no significant differences were found among the extruded diets. Extrusion of the WF diet increased digestibility of protein and all amino acids. The greatest increase in digestibility after extrusion of the WF diet was observed for cysteine followed by tryptophan. Extrusion of the FM and SBM diets had no significant effect on amino acid digestibility. Digestibility of starch was, in general, increased by extrusion. It is concluded that the heat treatment involved in typical moist extrusion processing used for fish feed may be sufficient to inactivate most of the TIA in unheated soybean meal, and to increase digestibility of the protein in WF to approximately the same level as found for SBM and FM. Still, extrusion is a lenient process with minor effects on nutrient digestibility of diets containing fish meal or toasted soybean meal as major protein sources.  相似文献   

12.
Those interested in the design and manufacture of feeds for intensive fish farming face the basic concern of formulating mixtures for the best yield at the lowest costs. Of the macronutrients in the feed, protein has and continues to receive special consideration because fish present high and specific needs for this constituent. Traditionally, protein has been supplied primarily by fish meals. This paper presents a synthesis of the efforts made and the lines explored to achieve an effective reduction of the amount of fish meal in the feeds for fish, following two strategies: reduction of the protein in the feeds and the use of new raw materials to replace fish meal.  相似文献   

13.
消化率的高低是评价饲料营养价值的重要指标,但是粪便的不同收集方式会影响消化率的测定结果。研究观察了异育银鲫摄食后的排粪高峰以及排粪持续时间,探讨了粪便的不同收集方式对异育银鲫(Carassius auratus gibelio)(约100 g)表观消化率(Apparent digestibility coefficient,ADC)测定结果的影响。饲料中加入1%三氧化二铬(Cr2O3)作为指示剂,实验采用3种粪便收集方法(积粪器法、虹吸法和后肠取粪法),并且在积粪器法和虹吸法中设置了不同的收粪时间。结果表明,正常投喂的异育银鲫摄食后的排粪高峰出现在摄食结束后的5—10h;饥饿2d的异育银鲫恢复摄食后的排粪高峰出现在摄食结束后的7—9h;饲料的干物质表观消化率(ADC of dry matter,ADCd)和蛋白表观消化率(ADC of protein,ADCp)在排粪初始阶段较低,随着排粪高峰的出现而升高。粪便的不同收集方法和不同收集时间对ADCd和ADCp的测定结果均存在显著影响(P<0.05)。采用虹吸法收集粪便测得的ADCd与在排粪高峰时段内积粪器法的测定值相当;后肠取粪法收集粪便测得的ADCd低于积粪器法排粪高峰期的测定值。采用虹吸法收集粪便测得的ADCp略低于在排粪高峰时段内积粪器法的测定值;后肠取粪法收集粪便测得的ADCp低于积粪器法各时间段内的测定值。因此,在选择挑选新鲜完整粪便的前提下,在排粪高峰期采用虹吸法收集粪便用于ADC的测定是一种方便可靠的方法,反而后肠取粪法由于操作误差容易带来更大偏差。  相似文献   

14.
Aims:  To develop a strain-specific rapid assay for identification and quantification of Lactobacillus rhamnosus GG in human faecal samples.
Methods and Results:  A unique random amplified polymorphic DNA (RAPD) band of the L. rhamnosus GG strain was isolated and sequenced. Strain-specific polymerase chain reaction (PCR) primers and probes were designed based on the sequence. Quantification was performed by the real-time PCR using a fluorescent resonance energy transfer (FRET) system. The specificity of the assay was tested with DNA isolated from a set of known strains and human faecal samples. The analytical sensitivity of the method for L. rhamnosus GG was about 10 CFU per assay, which corresponds to 105 CFU g−1 of wet faeces.
Conclusions:  Quantitative real-time PCR is a suitable method for strain-specific identification of L. rhamnosus GG in human faecal samples.
Significance and Impact of the Study:  Lactobacillus rhamnosus GG is one of the most studied probiotic strains in clinical trials but still lacks a DNA-based identification method. This study describes a real-time PCR method for strain-specific identification and quantification of L. rhamnosus GG in human faecal samples.  相似文献   

15.
A study was conducted to determine the effect of various low cost organic wastes as flavinogenic factors and the various concentrations at which they induced flavinogenecity resulting in higher yields of riboflavin. A high-yielding riboflavin strain; Eremothecium ashbyii NRRL 1363 was chosen to determine the flavinogenicity. Carbon source at 50 g l(-1) (dextrose equivalents) of molasses and nitrogen source at 50 g l(-1) (weight/volume) of peanut seed cake were found to be optimal levels to yield higher riboflavin. Among the organic wastes, (beef extract, hog casings, blood meal, fish meal) hog casings in association with fish meal supported the highest yield of riboflavin. Among the different recovery processes studied, a vacuum drying process was the most efficient allowing maximum yield, followed by drying at 90 degrees C and freeze-drying. It is apparent from this study that inexpensive or waste organic materials could induce E. ashbyii to synthesize and secrete riboflavin at higher levels in the medium and this could be purified using a vacuum drying process. This bioconversion process allows us to recycle the biomaterials and produce a value-added product of economic importance.  相似文献   

16.
The horse’s hindgut bacterial ecosystem has often been studied using faecal samples. However few studies compared both bacterial ecosystems and the validity of using faecal samples may be questionable. Hence, the present study aimed to compare the structure of the equine bacterial community in the hindgut (caecum, right ventral colon) and faeces using a fingerprint technique known as Automated Ribosomal Intergenic Spacer Analysis (ARISA). Two DNA extraction methods were also assessed. Intestinal contents and faeces were sampled 3 h after the morning meal on four adult fistulated horses fed meadow hay and pelleted concentrate. Irrespective of the intestinal segment, Principal Component Analysis of ARISA profiles showed a strong individual effect (P<0.0001). However, across the study, faecal bacterial community structure significantly (P<0.001) differed from those of the caecum and colon, while there was no difference between the two hindgut communities. The use of a QIAamp® DNA Stool Mini kit increased the quality of DNA extracted irrespective of sample type. The differences observed between faecal and hindgut bacterial communities challenge the use of faeces as a representative for hindgut activity. Further investigations are necessary to compare bacterial activity between the hindgut and faeces in order to understand the validity of using faecal samples.  相似文献   

17.
本研究探讨了通过收集器不同粪便收集时间和饲料中肉骨粉(MBM)含量对异育银鲫干物质、蛋白、能量、磷的表观消化率 (ADC) 影响.不同梯度(0, 20, 40, 60, 80 ,100%)的肉骨粉替代鱼粉(FM) 蛋白配制成六种等氮 (粗蛋白: 410 g/kg) 等能 (总能: 18 kJ/g) 的饲料,通过11周的饲养实验,实验开始后2周开始收集粪便,收集时间分别是:排粪后 1 min, 投喂后4h和16h. 结果表明,干物质、蛋白、能量、磷的消化率明显随粪便收集时间增加而升高(p<0.05),但在高肉骨粉替代饲料中差异不显著(p>0.05). 干物质、蛋白、能量、磷的消化率随饲料中肉骨粉含量的增加呈线性或近线性下降.因此,在消化率测定中应该尽快收集排出的粪便以保证消化率的真实性.消化率是影响肉骨粉利用一个因素.  相似文献   

18.
Abstract

The effects of moist extrusion processing of diets containing fish meal (FM) and conventional defatted soybean meal (SBM) or untoasted defatted soybean meal (white flakes [WF]) on amino acid composition, trypsin inhibitor activity (TIA), and apparent total tract digestibility of nutrients were studied. Three diets with the nutritional characteristics of feeds for salmonid fish were formulated: one control based on FM as protein source and two others where 40% of total amino acids from FM were substituted by either SBM or WF. Each diet was fed to mink either as an unextruded mixture of the ingredients or as extruded pellets in order to determine the effect of extrusion processing. Extrusion did not change the amino acid composition of the diets significantly, but reduced the TIA of both diets containing soy products by approximately 76%. Intake of the unextruded WF diet was only one-third compared with the other diets. The dry matter concentration in faeces from mink fed diets containing soy products was significantly lower than in mink fed the FM diet. Digestibility of crude protein, all amino acids and fat was lower, but starch higher, in the unextruded WF diet than in the FM and SBM diets, whereas no significant differences were found among the extruded diets. Extrusion of the WF diet increased digestibility of protein and all amino acids. The greatest increase in digestibility after extrusion of the WF diet was observed for cysteine followed by tryptophan. Extrusion of the FM and SBM diets had no significant effect on amino acid digestibility. Digestibility of starch was, in general, increased by extrusion. It is concluded that the heat treatment involved in typical moist extrusion processing used for fish feed may be sufficient to inactivate most of the TIA in unheated soybean meal, and to increase digestibility of the protein in WF to approximately the same level as found for SBM and FM. Still, extrusion is a lenient process with minor effects on nutrient digestibility of diets containing fish meal or toasted soybean meal as major protein sources.  相似文献   

19.
We investigate using relative amounts of prey DNA recovered from pinniped faeces to obtain diet composition data. Faeces were obtained from captive sea lions being fed a diet containing three fish species (50%, 36% and 14% by mass). Real-time PCR was used to quantify mtDNA in undigested tissue and in the faecal samples. The percent composition of fish mtDNA extracted from tissue corresponded reasonably well to the mass of fish in the mixture. In faecal samples the absolute amount of fish mtDNA recovered varied 100-fold, but the percent composition of the samples was relatively consistent (57.5 ± 9.3%, 19.3 ± 6.6% and 23.2 ± 12.2%). These results indicate there are prey-specific biases in DNA survival during digestion. However, the biases may be less than those commonly observed in conventional diet studies.  相似文献   

20.
Effects of salts on pasting, thermal, and rheological properties of rice starch (RS) in the presence of non-ionic (guar gum; GG) or ionic (xanthan; XT) hydrocolloid were studied. Rapid visco-analysis (RVA) showed that addition of salts significantly increased peak, breakdown, and final viscosities, and pasting temperatures of RS/XT blends, whereas those of RS/GG blends were varied depending on the type of salts added. Differential scanning calorimetry (DSC) demonstrated that salt addition significantly increased gelatinization temperatures of either RS/GG or RS/XT blend, whereas gelatinization enthalpy was less affected. Dynamic viscoelastic tests revealed that addition of salts had a more pronounced effect on enhancing structure formation of RS/XT gels than that of RS/GG gels. The steady shear viscosity was generally in line with the values of final viscosity obtained during pasting. These results would be used as a guideline for developing starch-based food products containing salts.  相似文献   

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