Organic wastes are one of the greatest challenges that cities face worldwide. In numerous underdeveloped nations, like Cameroon, waste is often disposed of through landfills, composting, or open-air combustion. Unfort...Organic wastes are one of the greatest challenges that cities face worldwide. In numerous underdeveloped nations, like Cameroon, waste is often disposed of through landfills, composting, or open-air combustion. Unfortunately, the concept of waste sorting and organic waste processing is new to many individuals. This has led to an increase in the amount of organic waste and the costs connected with its management. Consequently, the majority of developing nations have sought out waste management solutions that are more cost-effective. Therefore, it has been determined that the bioconversion of organic wastes by black soldier fly larvae (BSFLs) (Hermetia illucens) into multifunctional prepupae is a viable alternative. Appreciation is given to the employment of the organic waste management approach in developing nations since it is not only environmentally friendly and economically viable, but also provides a means for waste valorisation through the production of diverse resources and potential economic benefits. Studies have proved the usefulness of the insect in controlling organic wastes, but countries such as Cameroon are still unfamiliar with the nuances of this method. Consequently, this timely review examined the performance of the BSFL, specifically in organic waste treatment, as well as the best practices for multiplying them to determine its viability for use in a waste treatment plant, the production of high-quality larvae as a source of protein for livestock, and the production of diesel fuel.展开更多
Biodiesel, a renewable energy source made from natural oils and fats, can be produced using white raffia larvae as a raw material. These larvae have a high lipid content and a short life cycle, making them suitable fo...Biodiesel, a renewable energy source made from natural oils and fats, can be produced using white raffia larvae as a raw material. These larvae have a high lipid content and a short life cycle, making them suitable for this purpose. One crucial step in biodiesel production is oil extraction, and this study aimed to investigate how the extraction protocol affects the fuel properties of the oil. To study the impact of solvent type, solvent volume, and residence time on oil yield, 200 grams of Rhynchophorus ferrugineus were used in a Soxhlet extractor. The researchers examined the physicochemical properties and fatty acid composition of the crude grease using the European biodiesel standard (EN14214) and gas chromatography methods, respectively. The study found that hexane as a solvent produced the highest oil yield (64.44%) during a four-hour extraction period with a solvent ratio of 300 ml. Furthermore, the hexane-extracted oil had the highest iodine number (3.02 g/100 g) and cetane number (55.69). These values indicate favorable properties for biodiesel production. The Rhynchophorus ferrugineus larvae oil proved to be a rich source of monounsaturated fatty acids (76%), which were found to be significantly affected by the solvent type. Based on quality assessment, Rhynchophorus ferrugineus can be suitable for biodiesel production. In summary, under the given operational conditions, hexane is the most suitable solvent for Rhynchophorus ferrugineus oil extraction for biodiesel production. Further research in optimizing the extraction process can contribute to the efficient utilization of renewable energy sources like white raffia larvae for biodiesel production.展开更多
Cutaneous larva migrans(CLM) represents the most common tropically acquired dermatosis.CLM is caused by infection with hookworm larvae in tropical and sub-tropical areas,and people who have a history of foreign travel...Cutaneous larva migrans(CLM) represents the most common tropically acquired dermatosis.CLM is caused by infection with hookworm larvae in tropical and sub-tropical areas,and people who have a history of foreign travel and of walking barefoot on sandy soil or beaches are at a high risk of getting infected with it.The diagnosis is usually made on the basis of the typical appearance of the lesion,intense itching and history of foreign travel.CLM is a common parasitic skin disease that can be easily prevented by wearing 'protective' footwear.A case of CLM is described in this article.展开更多
Objective:To evaluate the effectiveness and residual effects of trypsin modulating ecstatic factor-Bacillus thuringiensis israeliensis(TMOF-Bti) formulations against Aedes aegypti(Ae. aegypti)(L) larvae at UKM Campus ...Objective:To evaluate the effectiveness and residual effects of trypsin modulating ecstatic factor-Bacillus thuringiensis israeliensis(TMOF-Bti) formulations against Aedes aegypti(Ae. aegypti)(L) larvae at UKM Campus Kuala Lumpur.Methods:Twenty first instar Ae.aegypti larvae were added in each bucket containing 4 L of water supplied with crushed dried-leaf powder as their source of food.Combination of TMOF-Bti in rice husk formulation with the following weights viz 10,25,50 and 100 mg,respectively in duplicate was distributed in the buckets;while TMOF-Bti in wettable powder formulation each weighing viz 2,5,10 and 20 mg,respectively in duplicate was also placed in the buckets.The control buckets run in duplicate with 4 L of water and 20 first instar Ae.aegypti larvae.All buckets were covered with mosquito netting.Larval mortality was recorded after 24 hours and weekly for five weeks.A new batch of 20 1^(st) instar larvae Ae.aegypti was introduced into each bucket weekly without additional TMOF-Bti rice husk formulation or wettable powder.The experiment was repeated for four times.Results:The result of the study showed that all formulations were very effective on the first two weeks by giving 100% larval mortality for all concentrations applied.The TMOF(2%) + Bti(2%) had a good residual effect until the end of 3^(rd) week,TMOF(4%) + Bti(4%) until 4^(th) week,wettable powder TMOF(20%) + Bti(20%) until the third week.Condusions:From the results it can be concluded that the TMOF-Bti formulations can be utilized in dengue vector control.展开更多
Background:The possibility of partially replacing soybean meal(SBM)with Hermetia illucens(HI)defatted larvae meal in broiler nutrition has frequently been suggested.For sustainability reasons,however,the larvae fat pr...Background:The possibility of partially replacing soybean meal(SBM)with Hermetia illucens(HI)defatted larvae meal in broiler nutrition has frequently been suggested.For sustainability reasons,however,the larvae fat produced during defatting should also be used and could be particularly beneficial regarding gut health due to its fatty acid composition.To evaluate the suitability of HI larvae as protein and fat source,a 2×3 factorial arrangement with two types of protein,i.e.SBM(S)or SBM and 15%of its crude protein replaced by HI larvae meal(L),and three levels of fat sources,namely 0(0 L),50%(50 L)or 100%HI larvae fat(100 L)at the expense of soybean oil was applied.Results:In the starter phase,an interaction showed higher body weight(BW),average daily gain(ADG)and improved feed conversion ratio(FCR)if 50%or 100%HI larvae fat was fed with HI larvae meal.Moreover,BW,ADG and FCR improved when feeding HI larvae meal as protein source.Additionally,we observed an increased average daily feed intake in the grower,finisher,and overall phase in the L groups and an improved FCR in 0 L compared to 50 L groups during the overall period.Regarding apparent ileal digestibility,HI larvae meal feeding increased dry matter,organic matter,and fat digestibility.Feeding HI larvae meal as protein source decreased the concentrations of agmatine,spermidine,spermine and ammonia in the caecal digesta,whereas fat source affected agmatine with higher concentrations in 50 L compared to 0 L in the colonic digesta.In contrast,caecal ethanolamine concentrations increased in HI larvae meal groups compared to SBM.Caecal butyric acid concentrations decreased with HI larvae meal feeding.An interaction was found for the jejunal villus area,being higher in L+100 L compared to S+100 L.Furthermore,L groups had greater villus width.Conclusions:A partial replacement of SBM with HI larvae meal and soybean oil with HI larvae fat in broiler diets without impairing animal performance or gut health seems possible.Feeding HI larvae meal affected broiler performance positively in the starter phase and improved apparent ileal digestibility.展开更多
Background: Insects, such as Hermetia illucens larvae, are rich in chitin and proteins, and represent a suitable feed ingredient replacement for animals. However, little is known about the effect of administering H. i...Background: Insects, such as Hermetia illucens larvae, are rich in chitin and proteins, and represent a suitable feed ingredient replacement for animals. However, little is known about the effect of administering H. illucens larvae on intestinal microbiota, bacterial metabolite profiles, and mucosal immune status in animals. This study aimed to investigate the effects of administering H. illucens larvae on colonic microbiota and bacterial metabolites production in finishing pigs. Seventy-two crossbred(Duroc × Landrace × Large White) female pigs(initial body weight, 76.0 ± 0.52 kg) were randomly allocated to three different dietary treatments: a control diet(Control group) and two diets corresponding to 4%(H1 group) and 8%(H2 group) H. illucens larvae inclusion levels, respectively. Each treatment consisted of eight pens(replicates), with three pigs per pen. After 46 days of feeding, eight pigs per treatment(n =8) were slaughtered, and the colonic digesta and mucosa were collected for microbial composition and microbial fermentation products, and genes expression analyses.Results: The results showed that the H1 diet significantly increased the abundance of Lactobacillus,Pseudobutyrivibrio, Roseburia, and Faecalibacterium compared with those in the control group(P < 0.05), with a decrease in the abundance of Streptococcus. The numbers of Lactobacillus, Roseburia, and Clostridium cluster XIVa were significantly greater in the H1 group than in the control group(P < 0.05). Meanwhile, H2 diet increased the number of Clostridium cluster XIVa compared with the control group(P < 0.05). For colonic metabolites, total short chain fatty acids, butyrate, and isobutyrate concentrations were significantly higher in the H1 group than those in the control group(P < 0.05);the H1 treatment caused a striking decrease in protein fermentation compared with the control group, as the concentrations of total amines, cadaverine, tryptamine, phenol, p-cresol, and skatole were significantly lower(P < 0.05). Additionally, H2 diet also increased butyrate concentration compared with control group(P < 0.05), while decreased the concentrations of phenol, p-cresol, and skatole(P < 0.05). Pigs in the H1 group down-regulated the expression of TLR-4 and pro-inflammatory cytokines(IFN-γ) compared with pigs in the control group(P < 0.05), and up-regulated anti-inflammatory cytokine(IL-10) and intestinal barrier genes(ZO-1, occludin, and mucin-1). H2 diet up-regulated the expression of ZO-1 compared with control group(P < 0.05). Furthermore, the changes in the colonic mucosal gene expression were associated with changes in the bacterial composition and their metabolites.Conclusions: Collectively, dietary inclusion of Hermetia illucens larvae may enhance mucosal immune homeostasis of pigs via altering bacterial composition and their metabolites. These findings provide a new perspective on insect meal as a sustainable protein source rich in nutrient ingredients for swine.展开更多
Objective:To determine lead level primarily in Culex quinquefasciatus(Cx.quinquefasciatus), and Culex gelidus(Cx.gelidus) larvae inhabiting lead consuming factories,and to putatively estimate eco-toxicological impact ...Objective:To determine lead level primarily in Culex quinquefasciatus(Cx.quinquefasciatus), and Culex gelidus(Cx.gelidus) larvae inhabiting lead consuming factories,and to putatively estimate eco-toxicological impact of effluents from the firms.Methods:Third instars larvae were sampled by standard dipping method and lead concentrations in the larvae and their respective surrounding factory aquatic environments were determined through standard atomic absorption spectrophotometry(AAS).Results:Cx.quinquefasciatus was the most abundant species followed by Cx.gelidus.The levels of lead were higher in the Cx.quinquefasciatus(1.08-47.47μg/g),than in the wastewaters surface(0.01-0.78 μg/mL) from the factories or closer areas around factories. Other species were not reaching the.criteria for lead determination.Conclusions:The Cx. quinquefasciatus larvae can bio-accumulate the metal and can potentially serve as a biomarker of lead contamination,to complemente conventional techniques.展开更多
The morphological characters on different developmental phases of embryo and larva and the schedule of the whole early developmental process in Styela canopus were observed and described. The types of reproduction and...The morphological characters on different developmental phases of embryo and larva and the schedule of the whole early developmental process in Styela canopus were observed and described. The types of reproduction and early development as well as the morphology of egg and larva in different ascidian species were compared. Styela canopus is oviparous. Its egg, 230.4～ 336.0?μm in diameter, is equipped with extraembryonic cell layers measured 43.2～ 63.0?μm thick. The early development of Styela canopus is typical urodele development, including fertilization, cleavage, gastrulation, tadpole in membrane, tadpole, initiating metamorphosis and juvenile. The tadpole of Styela canopus, with a length of 0.6～0.9 mm, consists of trunk and tail. There are obvious notochord, ocellus and adhesive papillae in the tadpole. Under the water temperature of (25±0.5)℃ and the salinity of 27.0, the larva was hatched after 9.5～11.0 h since the fertilization.2お?展开更多
During the First Chinese Antarctic Expedition zooplankton samples were collected at each of the oceanography stations in the waters around South Sheltland Islands (S. S. Is.) and in the northern part of the Bellinshau...During the First Chinese Antarctic Expedition zooplankton samples were collected at each of the oceanography stations in the waters around South Sheltland Islands (S. S. Is.) and in the northern part of the Bellinshausen Sea from 20 January to 12 February, 1985 by vertical tows of an 80 cm diameter conical net from 200 m to surface. Two deep tows with a closing net. were performed in slope water north of S.S. Is, and in the basin of Bransfield Strait. Eggs and larvae of Euphatisia superba Dana in zooplankton samples were identified and counted.There were four records of eggs from 27 stations. Most catches were of small number and restricted to within the nearshore area south of S.S Is.The largest number (1500/1000 cubic meters )was found in the outer side of Smith Island.No Nauplius was found . The earliest stage we found 【was Metanauplius , in two deep tows. The distribution of Calyptopis MI and Furcili I-III were quite similar. They were found mainly in three areas: 1 ) nearshore water along the展开更多
Decreasing fish resources in estuaries is a subject of anthropogenic activities. Studies of the spatiotemporal distribution of fish eggs and larvae can help identify the status and processes underlying recruitment in ...Decreasing fish resources in estuaries is a subject of anthropogenic activities. Studies of the spatiotemporal distribution of fish eggs and larvae can help identify the status and processes underlying recruitment in a fishery. As the fifth largest river estuary in the world, the Huanghe (Yellow) River estuary (HRE) is a typical estuary that has been seriously aff ected by human activities. Annual surveys on ichthyoplankton and environmental factors were conducted in the months of May of 2005 and 2009-2016 in the HRE to investigate the spatiotemporal distribution of fish eggs and larvae and the associated infl uencing factors. A total of 23 and 20 species of eggs and larvae, respectively, were collected. The dominant orders were Perciformes (51.2%) and Clupeiformes (25.6%). The average number of fish species eggs and larvae were 6.0 and 4.1 in average abundance of 0.91 and 0.13 ind./m^3 , respectively. The dominant species were mainly low-commercial-value small-sized fishes, such as Clupanodon punctatus , Harengula zunasi, and Acanthogobius, whereas certain traditional commercial fishes, such as Trichiurus lepturus , and Clupea pallasii, were not seen. Analysis of the fish egg and larval community revealed four temporal assemblages and two spatial assemblages. Salinity was the main factor on the spatial distribution of ichthyoplankton communities, the species number and Shannon-Weiner diversity index (H′) of the fish egg and larval community near the river mouth with lower salinity were signifi cantly lower than the community far away from the river mouth with higher salinity. In addition, increases of water temperature promoted the number and abundance of fish species eggs, and the areas of abundant prey tended to have a more diversified and abundant of ichthyoplankton species. In overall, overfishing, dam construction, and other human activities were the main drivers that led to the substantial decline in fishery resources in the HRE.展开更多
Using modified clay is one of the most promising methods for the mitigation of harmful algal blooms(HABs).However,the environmental impact of modified clay has become a subject of global concern.In this study,turbot(S...Using modified clay is one of the most promising methods for the mitigation of harmful algal blooms(HABs).However,the environmental impact of modified clay has become a subject of global concern.In this study,turbot(Scophthalmus maximus L.)embryos were used as a model to assess the effect of modified clay on this sensitive stage of fish development.Results show that the 24 and 48h LC 50(median lethal concentrations)of the modified clay were 1.70 and 1.65 g/L,and the safe concentration was 0.47 g/L,which is much higher than the concentration used to treat HAB.The modified clay did not affect significantly the hatchability of turbot embryos but when the concentration exceeded 0.50 g/L,the deformity rate of newly hatched larvae increased significantly.The total length,specific growth rate(SGR)and yolk sac absorption rate of larvae reached their peaks at 0.50 g/L and then gradually decreased as the concentration of modified clay increased.Therefore,a moderate amount of modified clay does not harm the survival and hatching of turbot embryos,or the growth and development of newly hatched larvae.展开更多
Oxygen uptake under starvation and short periods of sudden temperature change was measured forlarval herring （Clupea harengus L.） reared at average temperature of 7.3, 11 and 12.9℃. Larval stagesbetween first feedi...Oxygen uptake under starvation and short periods of sudden temperature change was measured forlarval herring （Clupea harengus L.） reared at average temperature of 7.3, 11 and 12.9℃. Larval stagesbetween first feeding and premetamorphosis were used. For comparison, the routine oxygen uptake（ROU） was also investigated and followed the relationship Q=0.974+0. 174 tW<sup>0.210</sup>, where Q is in μg/（mg·h）, W is dry body weight in mg and t is temperature in ℃. The oxygen uptake under starvation（SOU, deprived of food for 24 h） was different from the routine when the larval dry weightwas less than 0.6-0.8 mg, it increased with temperature and body weight giving the reationship Q=1.568+0.110 tW<sup>0.380</sup>, if the larval dry weight mp more than 0.6-0.8 mg, it reverted to the norm(Q=1.704+0.078 tW<sup>-0.349</sup>). The oxygen uptake was tested in short periods （3 h） of sudden temperaturechanges in six groups: 7.3 to 11, 7.3 to 12.9, 11 to 7.3. 11 to 12.9, 12.9 to 7.3 and 1.29 to11℃. The oxygen uptake in the 7.3 to 12.9 and展开更多
The epidemiological investigations on the disease and death in mature eggs, embryonic de- velopmental periods and larvae populations [including oocytes, fertilized ovum, early embryonic phase larvae (6 h), D-shaped ph...The epidemiological investigations on the disease and death in mature eggs, embryonic de- velopmental periods and larvae populations [including oocytes, fertilized ovum, early embryonic phase larvae (6 h), D-shaped phase larvae (24 h), early umbo phase larvae, umbo phase larvae, post um- bo phase larvae and eyespot phase larvae] in the Luhuitou Pearl Oyster Mariculture Farm of Sanya City, Hainan Province in April 1995 showed that there were two peaks of mortality rates which occurred in early umbo phase or umbo phase and post umbo phase (Figs 3-5 and Table 1) respectively from pre- embryonic developmental periods to larvae phases. It indicated that the onset and death of Pinctada maxima larvae populations followed a pattem of outbreak. Between the prevalence, intensity of RLO infection and the mortality rates of larvae populations were of obvious positively correlations. Generally, every peak of RLO infection is always follwed by a peak of mortality rate of larvae hosts, and the mor- tality rates of larvae hosts declined with the decreased RLO infection (see Figs 3-5 ). Under the trans- mission electron microscopy (TEM), no rickettsia-like organisms were discovered in oocytes, fertilized ovum and early embryonic phase larvae (6 h). The RLO inclusions occurred first in the D-shaped phase larvae (24 h) under histological examination. Absences of RLO in transmission electron exami- nation of oocytes of RLO-infected adult females, ferilized ovum and early embryonic phase larvae (6 h) indicated that RLO may not be transmitted transovarially. But RLO for host infection may be trans- mitted by contact transmission since RLO inclusions were first identified regularly in D-shaped phase larvae (24 h), while these D-shaped phase larvae were still unable to take food during hatching 24 hours. In addition, the result of epidemiological investigation showed that no odservable death occurred in D-shaped larvae populations, but early obvious death occurred in larvae populations in the seventh day after fertilization, in a rate of about 21. 8%. It indicated that there was a incubation peried from RLO infection for host (D-shaped phase larvae) to host onset and death occurred clinically.展开更多
The larvae of Styela canopus show the highest rates of settlement and metamorphosiswhen treated with 40 mM KCl-elevated seawater at 25 ℃ in temperature and 27.0 in salinity. Inducedby 40 mM KCl-elevated seawater, it ...The larvae of Styela canopus show the highest rates of settlement and metamorphosiswhen treated with 40 mM KCl-elevated seawater at 25 ℃ in temperature and 27.0 in salinity. Inducedby 40 mM KCl-elevated seawater, it took Styela canopus larvae approximately 3 h after hatching to de-velop competence to settle and metamorphose. The present experiment shows that Styela canopus larvaeis an ideal model organism for examining the efficiency of antifouling substance.展开更多
Antibiotics are widespread in various environmental media,and may pose a potential threat to aquatic ecosystems and non-target aquatic organisms.Florfenicol(FLO)is one of the most commonly used antibiotics in aquacult...Antibiotics are widespread in various environmental media,and may pose a potential threat to aquatic ecosystems and non-target aquatic organisms.Florfenicol(FLO)is one of the most commonly used antibiotics in aquaculture,and extensively used to substitute chloramphenicol with its strong sterilization and low adverse ef fect.In this study,flounder Paralichthys olivaceus,an important economic fish species in seawater was used as an experimental subject.Five exposure concentrations of FLO(including environmentrelated concentrations)were set at 0,0.01,0.1,1,and 10 mg/L.Ef fects of FLO exposure for 168 h on growth and development,motor behavior,antioxidant enzyme activity,malondialdehyde(MDA)content,and thyroid hormone level of P.olivaceus larvae were studied in pre-larvae(1 dpf)and post-larvae(20 dpf).The results show that the short-term FLO exposure could promote the larvae growth to some degrees,but inhibit them as the exposure time prolonged.For pre-larvae,FLO at 0.01 mg/L could stimulate the motor nerve system and increase the swimming ability,but inhibited it at 1 mg/L.With the increasing dosage of FLO,the superoxide dismutase(SOD)and MDA contents were elevated,reaching the maximum in the 1 mg/L FLO group.The pre-larvae were more sensitive than the post-larvae to FLO in the environment,and the growth and immune resistance could be damaged with long exposure.Post-larvae were more tolerant to external pollutants,FLO at 1 mg/L could promote the motor behavior and reduce SOD and MDA contents.Therefore,FLO can be used as an antibiotic at a proper concentration but as a drug to prevent disease in a long-term way.展开更多
The survival rates of shrimp larvae in different stage are higher than those of control groups when probiotic bacteria strains X4B 1 and X1B 1 which are isolated from gut of adult shrimp are added into the little volu...The survival rates of shrimp larvae in different stage are higher than those of control groups when probiotic bacteria strains X4B 1 and X1B 1 which are isolated from gut of adult shrimp are added into the little volume rearing sea water of shrimp larvae. The effects of probiotic bacteria are evaluated by challenge test (pathogenic bacteria Z 3G 2 isolated from disease shrimp larvae in the hatchery of Jimo town) and low salinity stress resistance tests on shrimp larvae, the survival rate and lengths of the shrimp larvae in the experiment are determined. Results indicate that 1. The survival rate, ability of resistant to low salinity, lengths of the delivered shrimp larvae are improved after the strains of probiotic bacteria, X4B 1 or X1B 1, are added into the rearing sea water of hatchery. 2. The addition of the probiotic bacteria could not influence the change of the bacteria number, NH3 N and COD value in the rearing sea water. 3. The probiotic bacteria used in the experiment have many enzymes such as Lipase, Amylase, Gelatinase and Lecithinase. These enzymes may help the probiotic bacteria to digest the food components fed to shrimp larvae and increase the digestive efficiency of post larvae. This may be one of the reasons why these probiotic bacteria are beneficial to the shrimp larvae.展开更多
This study evaluated efficacy of maternal and larval immunisation against Lactococcus garviae infection and on the lysozyme and immunoglobulin (IgM) levels in rainbow trout Oncorhynchus mykiss (Walaum). Forty-eight-da...This study evaluated efficacy of maternal and larval immunisation against Lactococcus garviae infection and on the lysozyme and immunoglobulin (IgM) levels in rainbow trout Oncorhynchus mykiss (Walaum). Forty-eight-day-old larvae (mean weight 96 mg) originating from injected weekly with letrozole and immunised, only immunised and non-immunised parents were experimentally infected with the L. garvieae, and the mortality rate was recorded daily. Larvae were vaccinated by immersion at 58 days post hatch with live L. garvieae (109 cells/mL) for 15 min. Every third day post larvae vaccination, two larvae from each group were collected for analysis lysozyme (by a method based on the ability of lysozyme to lyse the bacterium Micrococcus lysodeikticus) and IgM (by enzyme-linked immunosorbent assay (ELISA)) parameters. Vaccinated and control larvae were tested for protection against L. garvieae 30 days post larvae immunization when the larvae were 88 days old. Larvae were challenged by bath exposure with live L. garvieae (109 cells/mL) for 2 min and monitored for mortality for at least 10 days following challenge. The challenge experiment with L. garvieae showed a significant reduction in larvae from immunised (54.44% ± 0.64%) and injected weekly with letrozole and immunised fish (52.96% ± 0.97%) compared to larvae from control fish (62.96% ± 2.22%). Vaccinated larvae originated from injected weekly with letrozole and immunised parents showed significantly higher lysozyme activity compared to other fish groups. Vaccinated larvae showed significantly less mortality compared to controls. The relative percent survival (RPS) values of larvae from only immunised, injected weekly with letrozole and immunised and non-immunised parents vaccinated with L. garvieae were 67.36% ± 0.9%, 68.05% ± 0.66% and 48.27% ± 2.79% respectively. The results indicate that the effect of maternal immunization rainbow trout against L. garvieae infection by eliciting the immune responses as indicated by an increase in the IgM level and lysozyme activity.展开更多
Fish populations have declined in many estuarine and freshwater ecosystems in part due to the loss of habitat in recent decades.Reconstructing lost habitat for larvae fish is a potential method for recovering larvae f...Fish populations have declined in many estuarine and freshwater ecosystems in part due to the loss of habitat in recent decades.Reconstructing lost habitat for larvae fish is a potential method for recovering larvae fish populations.Three-dimensional artificial floating wetlands(AFWs)on which Phragmites australis was planted were experimentally deployed to recover the lost habitat in the Changjiang(Yangtze)River estuary from May to July 2018.The AFW area was characterized by slow velocity,high transparency,low dissolved oxygen,and relatively constant water temperature.The total individuals of larvae fish in the AFW area(12122 in total)was higher than that in the non-AFW area(1250 in total),and the densities of most larvae fish species were higher in the AFW habitat than in the non-AFW area.The distributions of larvae fish species were positively influenced by habitat type because they were strongly related to the negative part of the first axis of the redundancy analysis,and Cyprinus carpio and Cyprinus auratus were inclined to habitat in the slow velocity and high transparency AFW habitat area.These results indicate that larvae fish species are inclined to inhabit the AFW habitat.The use of three-dimensional P.australis AFWs would be a potential method for enhancing the habitat of larvae fish in the degraded habitats along the estuary.展开更多
For centuries, insects have been used as food due to their availability and easiness in raising that is much less burdensome for environment than animal husbandry breeding. Mealworm (Tenebrio molitor L.) is a store-pe...For centuries, insects have been used as food due to their availability and easiness in raising that is much less burdensome for environment than animal husbandry breeding. Mealworm (Tenebrio molitor L.) is a store-pest of which larvae are consumed by people. The aim of the work was to determine the nutritional value of larvae of mealworm (Tenebrio molitor L.). The material was a three-month-old mealworm larva 25 -30 mmin length. Larvae were boiled for 3 min and next dried in 60℃. Contents of water, ash, minerals, protein, fat and fat acids profile have been determined. Fresh larvae contained 56% of water, 18% of total protein, 22% of total fat and 1.55% of ash. High contents of minerals were found in the larvae: magnesium (87.5 mg/100g), zinc (4.2 mg/100g), iron (3.8 mg/100g), copper (0.78 mg/100g) and manganese (0.44 mg/100g). The proportion of n-6/n-3 fatty acids was very advantageous and amounted to 6.76. Larvae powder contained twice higher content of protein, fat, ash and minerals. Larva of mealworm is a valuable source of nutrients in amounts more profitable for human organism than traditional meat food. Powdered larva is a high-grade product to be applied as a supplement to traditional meals.展开更多
This study showed Iethal concentrations (LC) of copper for Peneaus penicillatus at various stages ofits Iife cycle were 1000μg/L for nauplii, 1000μg/L for Zoea I, 2000μg/L for Zoea Il, 2500μg/Lfor Zoea III, 3000μ...This study showed Iethal concentrations (LC) of copper for Peneaus penicillatus at various stages ofits Iife cycle were 1000μg/L for nauplii, 1000μg/L for Zoea I, 2000μg/L for Zoea Il, 2500μg/Lfor Zoea III, 3000μg/L for Mysis I, II and III and that for almost 100% mortality for postlarvae was3000μg/L. For cadmium LC were 100μg/L for nauplii, 500μg/L for Zoea l, 1000μg/L forZoea II, 2000μg/L for Zoea III, 2500μg/L for Mysis I and 3500μg/L for Mysis II, III andpostlarvae. For tmixture of both metals, LC were 400μg/L for nauplii, 1000 μg/L for nauplii, 1000μg/L for Zoea I,2000μg/L for Zoea II and 3000μg/L for Mysis I, II, III and post larvae.展开更多
文摘Organic wastes are one of the greatest challenges that cities face worldwide. In numerous underdeveloped nations, like Cameroon, waste is often disposed of through landfills, composting, or open-air combustion. Unfortunately, the concept of waste sorting and organic waste processing is new to many individuals. This has led to an increase in the amount of organic waste and the costs connected with its management. Consequently, the majority of developing nations have sought out waste management solutions that are more cost-effective. Therefore, it has been determined that the bioconversion of organic wastes by black soldier fly larvae (BSFLs) (Hermetia illucens) into multifunctional prepupae is a viable alternative. Appreciation is given to the employment of the organic waste management approach in developing nations since it is not only environmentally friendly and economically viable, but also provides a means for waste valorisation through the production of diverse resources and potential economic benefits. Studies have proved the usefulness of the insect in controlling organic wastes, but countries such as Cameroon are still unfamiliar with the nuances of this method. Consequently, this timely review examined the performance of the BSFL, specifically in organic waste treatment, as well as the best practices for multiplying them to determine its viability for use in a waste treatment plant, the production of high-quality larvae as a source of protein for livestock, and the production of diesel fuel.
文摘Biodiesel, a renewable energy source made from natural oils and fats, can be produced using white raffia larvae as a raw material. These larvae have a high lipid content and a short life cycle, making them suitable for this purpose. One crucial step in biodiesel production is oil extraction, and this study aimed to investigate how the extraction protocol affects the fuel properties of the oil. To study the impact of solvent type, solvent volume, and residence time on oil yield, 200 grams of Rhynchophorus ferrugineus were used in a Soxhlet extractor. The researchers examined the physicochemical properties and fatty acid composition of the crude grease using the European biodiesel standard (EN14214) and gas chromatography methods, respectively. The study found that hexane as a solvent produced the highest oil yield (64.44%) during a four-hour extraction period with a solvent ratio of 300 ml. Furthermore, the hexane-extracted oil had the highest iodine number (3.02 g/100 g) and cetane number (55.69). These values indicate favorable properties for biodiesel production. The Rhynchophorus ferrugineus larvae oil proved to be a rich source of monounsaturated fatty acids (76%), which were found to be significantly affected by the solvent type. Based on quality assessment, Rhynchophorus ferrugineus can be suitable for biodiesel production. In summary, under the given operational conditions, hexane is the most suitable solvent for Rhynchophorus ferrugineus oil extraction for biodiesel production. Further research in optimizing the extraction process can contribute to the efficient utilization of renewable energy sources like white raffia larvae for biodiesel production.
文摘Cutaneous larva migrans(CLM) represents the most common tropically acquired dermatosis.CLM is caused by infection with hookworm larvae in tropical and sub-tropical areas,and people who have a history of foreign travel and of walking barefoot on sandy soil or beaches are at a high risk of getting infected with it.The diagnosis is usually made on the basis of the typical appearance of the lesion,intense itching and history of foreign travel.CLM is a common parasitic skin disease that can be easily prevented by wearing 'protective' footwear.A case of CLM is described in this article.
基金financially supported by Entogenex Industries Sdn.Bhd.,Malaysia(grant No.NN 001-2008)
文摘Objective:To evaluate the effectiveness and residual effects of trypsin modulating ecstatic factor-Bacillus thuringiensis israeliensis(TMOF-Bti) formulations against Aedes aegypti(Ae. aegypti)(L) larvae at UKM Campus Kuala Lumpur.Methods:Twenty first instar Ae.aegypti larvae were added in each bucket containing 4 L of water supplied with crushed dried-leaf powder as their source of food.Combination of TMOF-Bti in rice husk formulation with the following weights viz 10,25,50 and 100 mg,respectively in duplicate was distributed in the buckets;while TMOF-Bti in wettable powder formulation each weighing viz 2,5,10 and 20 mg,respectively in duplicate was also placed in the buckets.The control buckets run in duplicate with 4 L of water and 20 first instar Ae.aegypti larvae.All buckets were covered with mosquito netting.Larval mortality was recorded after 24 hours and weekly for five weeks.A new batch of 20 1^(st) instar larvae Ae.aegypti was introduced into each bucket weekly without additional TMOF-Bti rice husk formulation or wettable powder.The experiment was repeated for four times.Results:The result of the study showed that all formulations were very effective on the first two weeks by giving 100% larval mortality for all concentrations applied.The TMOF(2%) + Bti(2%) had a good residual effect until the end of 3^(rd) week,TMOF(4%) + Bti(4%) until 4^(th) week,wettable powder TMOF(20%) + Bti(20%) until the third week.Condusions:From the results it can be concluded that the TMOF-Bti formulations can be utilized in dengue vector control.
基金supported by the Federal Ministry Republic of Austria,Agriculture,Regions and Tourism(LE 14-20,Application number 16.1.1-S2-23/18 and 16.2.1.-S2-23/18),within an EIP-Project.
文摘Background:The possibility of partially replacing soybean meal(SBM)with Hermetia illucens(HI)defatted larvae meal in broiler nutrition has frequently been suggested.For sustainability reasons,however,the larvae fat produced during defatting should also be used and could be particularly beneficial regarding gut health due to its fatty acid composition.To evaluate the suitability of HI larvae as protein and fat source,a 2×3 factorial arrangement with two types of protein,i.e.SBM(S)or SBM and 15%of its crude protein replaced by HI larvae meal(L),and three levels of fat sources,namely 0(0 L),50%(50 L)or 100%HI larvae fat(100 L)at the expense of soybean oil was applied.Results:In the starter phase,an interaction showed higher body weight(BW),average daily gain(ADG)and improved feed conversion ratio(FCR)if 50%or 100%HI larvae fat was fed with HI larvae meal.Moreover,BW,ADG and FCR improved when feeding HI larvae meal as protein source.Additionally,we observed an increased average daily feed intake in the grower,finisher,and overall phase in the L groups and an improved FCR in 0 L compared to 50 L groups during the overall period.Regarding apparent ileal digestibility,HI larvae meal feeding increased dry matter,organic matter,and fat digestibility.Feeding HI larvae meal as protein source decreased the concentrations of agmatine,spermidine,spermine and ammonia in the caecal digesta,whereas fat source affected agmatine with higher concentrations in 50 L compared to 0 L in the colonic digesta.In contrast,caecal ethanolamine concentrations increased in HI larvae meal groups compared to SBM.Caecal butyric acid concentrations decreased with HI larvae meal feeding.An interaction was found for the jejunal villus area,being higher in L+100 L compared to S+100 L.Furthermore,L groups had greater villus width.Conclusions:A partial replacement of SBM with HI larvae meal and soybean oil with HI larvae fat in broiler diets without impairing animal performance or gut health seems possible.Feeding HI larvae meal affected broiler performance positively in the starter phase and improved apparent ileal digestibility.
基金supported by the Presidential Foundation of the Guangdong Academy of Agricultural Sciences(201802B,201621)Guangdong Modern Agro-industry Technology Research System(2016LM1080,2017LM1080)
文摘Background: Insects, such as Hermetia illucens larvae, are rich in chitin and proteins, and represent a suitable feed ingredient replacement for animals. However, little is known about the effect of administering H. illucens larvae on intestinal microbiota, bacterial metabolite profiles, and mucosal immune status in animals. This study aimed to investigate the effects of administering H. illucens larvae on colonic microbiota and bacterial metabolites production in finishing pigs. Seventy-two crossbred(Duroc × Landrace × Large White) female pigs(initial body weight, 76.0 ± 0.52 kg) were randomly allocated to three different dietary treatments: a control diet(Control group) and two diets corresponding to 4%(H1 group) and 8%(H2 group) H. illucens larvae inclusion levels, respectively. Each treatment consisted of eight pens(replicates), with three pigs per pen. After 46 days of feeding, eight pigs per treatment(n =8) were slaughtered, and the colonic digesta and mucosa were collected for microbial composition and microbial fermentation products, and genes expression analyses.Results: The results showed that the H1 diet significantly increased the abundance of Lactobacillus,Pseudobutyrivibrio, Roseburia, and Faecalibacterium compared with those in the control group(P < 0.05), with a decrease in the abundance of Streptococcus. The numbers of Lactobacillus, Roseburia, and Clostridium cluster XIVa were significantly greater in the H1 group than in the control group(P < 0.05). Meanwhile, H2 diet increased the number of Clostridium cluster XIVa compared with the control group(P < 0.05). For colonic metabolites, total short chain fatty acids, butyrate, and isobutyrate concentrations were significantly higher in the H1 group than those in the control group(P < 0.05);the H1 treatment caused a striking decrease in protein fermentation compared with the control group, as the concentrations of total amines, cadaverine, tryptamine, phenol, p-cresol, and skatole were significantly lower(P < 0.05). Additionally, H2 diet also increased butyrate concentration compared with control group(P < 0.05), while decreased the concentrations of phenol, p-cresol, and skatole(P < 0.05). Pigs in the H1 group down-regulated the expression of TLR-4 and pro-inflammatory cytokines(IFN-γ) compared with pigs in the control group(P < 0.05), and up-regulated anti-inflammatory cytokine(IL-10) and intestinal barrier genes(ZO-1, occludin, and mucin-1). H2 diet up-regulated the expression of ZO-1 compared with control group(P < 0.05). Furthermore, the changes in the colonic mucosal gene expression were associated with changes in the bacterial composition and their metabolites.Conclusions: Collectively, dietary inclusion of Hermetia illucens larvae may enhance mucosal immune homeostasis of pigs via altering bacterial composition and their metabolites. These findings provide a new perspective on insect meal as a sustainable protein source rich in nutrient ingredients for swine.
文摘Objective:To determine lead level primarily in Culex quinquefasciatus(Cx.quinquefasciatus), and Culex gelidus(Cx.gelidus) larvae inhabiting lead consuming factories,and to putatively estimate eco-toxicological impact of effluents from the firms.Methods:Third instars larvae were sampled by standard dipping method and lead concentrations in the larvae and their respective surrounding factory aquatic environments were determined through standard atomic absorption spectrophotometry(AAS).Results:Cx.quinquefasciatus was the most abundant species followed by Cx.gelidus.The levels of lead were higher in the Cx.quinquefasciatus(1.08-47.47μg/g),than in the wastewaters surface(0.01-0.78 μg/mL) from the factories or closer areas around factories. Other species were not reaching the.criteria for lead determination.Conclusions:The Cx. quinquefasciatus larvae can bio-accumulate the metal and can potentially serve as a biomarker of lead contamination,to complemente conventional techniques.
文摘The morphological characters on different developmental phases of embryo and larva and the schedule of the whole early developmental process in Styela canopus were observed and described. The types of reproduction and early development as well as the morphology of egg and larva in different ascidian species were compared. Styela canopus is oviparous. Its egg, 230.4～ 336.0?μm in diameter, is equipped with extraembryonic cell layers measured 43.2～ 63.0?μm thick. The early development of Styela canopus is typical urodele development, including fertilization, cleavage, gastrulation, tadpole in membrane, tadpole, initiating metamorphosis and juvenile. The tadpole of Styela canopus, with a length of 0.6～0.9 mm, consists of trunk and tail. There are obvious notochord, ocellus and adhesive papillae in the tadpole. Under the water temperature of (25±0.5)℃ and the salinity of 27.0, the larva was hatched after 9.5～11.0 h since the fertilization.2お?
文摘During the First Chinese Antarctic Expedition zooplankton samples were collected at each of the oceanography stations in the waters around South Sheltland Islands (S. S. Is.) and in the northern part of the Bellinshausen Sea from 20 January to 12 February, 1985 by vertical tows of an 80 cm diameter conical net from 200 m to surface. Two deep tows with a closing net. were performed in slope water north of S.S. Is, and in the basin of Bransfield Strait. Eggs and larvae of Euphatisia superba Dana in zooplankton samples were identified and counted.There were four records of eggs from 27 stations. Most catches were of small number and restricted to within the nearshore area south of S.S Is.The largest number (1500/1000 cubic meters )was found in the outer side of Smith Island.No Nauplius was found . The earliest stage we found 【was Metanauplius , in two deep tows. The distribution of Calyptopis MI and Furcili I-III were quite similar. They were found mainly in three areas: 1 ) nearshore water along the
基金Supported by the National Natural Science Foundation of China—Shandong Provincial Joint Fund for Marine Science Research Centers(No.U1606404)the National Key Basic Research Program of China(973 Program)(No.2015CB453301)the National Marine Public Welfare Research Project of China(No.201405007)
文摘Decreasing fish resources in estuaries is a subject of anthropogenic activities. Studies of the spatiotemporal distribution of fish eggs and larvae can help identify the status and processes underlying recruitment in a fishery. As the fifth largest river estuary in the world, the Huanghe (Yellow) River estuary (HRE) is a typical estuary that has been seriously aff ected by human activities. Annual surveys on ichthyoplankton and environmental factors were conducted in the months of May of 2005 and 2009-2016 in the HRE to investigate the spatiotemporal distribution of fish eggs and larvae and the associated infl uencing factors. A total of 23 and 20 species of eggs and larvae, respectively, were collected. The dominant orders were Perciformes (51.2%) and Clupeiformes (25.6%). The average number of fish species eggs and larvae were 6.0 and 4.1 in average abundance of 0.91 and 0.13 ind./m^3 , respectively. The dominant species were mainly low-commercial-value small-sized fishes, such as Clupanodon punctatus , Harengula zunasi, and Acanthogobius, whereas certain traditional commercial fishes, such as Trichiurus lepturus , and Clupea pallasii, were not seen. Analysis of the fish egg and larval community revealed four temporal assemblages and two spatial assemblages. Salinity was the main factor on the spatial distribution of ichthyoplankton communities, the species number and Shannon-Weiner diversity index (H′) of the fish egg and larval community near the river mouth with lower salinity were signifi cantly lower than the community far away from the river mouth with higher salinity. In addition, increases of water temperature promoted the number and abundance of fish species eggs, and the areas of abundant prey tended to have a more diversified and abundant of ichthyoplankton species. In overall, overfishing, dam construction, and other human activities were the main drivers that led to the substantial decline in fishery resources in the HRE.
基金Supported by the National Key Research and Development Program of China(No.2017YFC1404300)the NSFC-Shandong Joint Fund for Marine Science Research Center(No.U1606404)the National Key Research and Development Program of China(No.2016YFE0101500)
文摘Using modified clay is one of the most promising methods for the mitigation of harmful algal blooms(HABs).However,the environmental impact of modified clay has become a subject of global concern.In this study,turbot(Scophthalmus maximus L.)embryos were used as a model to assess the effect of modified clay on this sensitive stage of fish development.Results show that the 24 and 48h LC 50(median lethal concentrations)of the modified clay were 1.70 and 1.65 g/L,and the safe concentration was 0.47 g/L,which is much higher than the concentration used to treat HAB.The modified clay did not affect significantly the hatchability of turbot embryos but when the concentration exceeded 0.50 g/L,the deformity rate of newly hatched larvae increased significantly.The total length,specific growth rate(SGR)and yolk sac absorption rate of larvae reached their peaks at 0.50 g/L and then gradually decreased as the concentration of modified clay increased.Therefore,a moderate amount of modified clay does not harm the survival and hatching of turbot embryos,or the growth and development of newly hatched larvae.
文摘Oxygen uptake under starvation and short periods of sudden temperature change was measured forlarval herring （Clupea harengus L.） reared at average temperature of 7.3, 11 and 12.9℃. Larval stagesbetween first feeding and premetamorphosis were used. For comparison, the routine oxygen uptake（ROU） was also investigated and followed the relationship Q=0.974+0. 174 tW<sup>0.210</sup>, where Q is in μg/（mg·h）, W is dry body weight in mg and t is temperature in ℃. The oxygen uptake under starvation（SOU, deprived of food for 24 h） was different from the routine when the larval dry weightwas less than 0.6-0.8 mg, it increased with temperature and body weight giving the reationship Q=1.568+0.110 tW<sup>0.380</sup>, if the larval dry weight mp more than 0.6-0.8 mg, it reverted to the norm(Q=1.704+0.078 tW<sup>-0.349</sup>). The oxygen uptake was tested in short periods （3 h） of sudden temperaturechanges in six groups: 7.3 to 11, 7.3 to 12.9, 11 to 7.3. 11 to 12.9, 12.9 to 7.3 and 1.29 to11℃. The oxygen uptake in the 7.3 to 12.9 and
基金This study was supported by the Projects under the Major State Basic Research Development Program under contractNo.G199012001,
文摘The epidemiological investigations on the disease and death in mature eggs, embryonic de- velopmental periods and larvae populations [including oocytes, fertilized ovum, early embryonic phase larvae (6 h), D-shaped phase larvae (24 h), early umbo phase larvae, umbo phase larvae, post um- bo phase larvae and eyespot phase larvae] in the Luhuitou Pearl Oyster Mariculture Farm of Sanya City, Hainan Province in April 1995 showed that there were two peaks of mortality rates which occurred in early umbo phase or umbo phase and post umbo phase (Figs 3-5 and Table 1) respectively from pre- embryonic developmental periods to larvae phases. It indicated that the onset and death of Pinctada maxima larvae populations followed a pattem of outbreak. Between the prevalence, intensity of RLO infection and the mortality rates of larvae populations were of obvious positively correlations. Generally, every peak of RLO infection is always follwed by a peak of mortality rate of larvae hosts, and the mor- tality rates of larvae hosts declined with the decreased RLO infection (see Figs 3-5 ). Under the trans- mission electron microscopy (TEM), no rickettsia-like organisms were discovered in oocytes, fertilized ovum and early embryonic phase larvae (6 h). The RLO inclusions occurred first in the D-shaped phase larvae (24 h) under histological examination. Absences of RLO in transmission electron exami- nation of oocytes of RLO-infected adult females, ferilized ovum and early embryonic phase larvae (6 h) indicated that RLO may not be transmitted transovarially. But RLO for host infection may be trans- mitted by contact transmission since RLO inclusions were first identified regularly in D-shaped phase larvae (24 h), while these D-shaped phase larvae were still unable to take food during hatching 24 hours. In addition, the result of epidemiological investigation showed that no odservable death occurred in D-shaped larvae populations, but early obvious death occurred in larvae populations in the seventh day after fertilization, in a rate of about 21. 8%. It indicated that there was a incubation peried from RLO infection for host (D-shaped phase larvae) to host onset and death occurred clinically.
基金National Natural Science Foundation of China under contract No. 49976034.
文摘The larvae of Styela canopus show the highest rates of settlement and metamorphosiswhen treated with 40 mM KCl-elevated seawater at 25 ℃ in temperature and 27.0 in salinity. Inducedby 40 mM KCl-elevated seawater, it took Styela canopus larvae approximately 3 h after hatching to de-velop competence to settle and metamorphose. The present experiment shows that Styela canopus larvaeis an ideal model organism for examining the efficiency of antifouling substance.
基金Supported by the National Key R&D Program of China(No.2017YFB0404000)the Project of Liaoning Ocean and Fisheries Department(No.201731)+1 种基金the Foundation of Key Laboratory of Industrial Ecology and Environmental Engineering Ministry of Education(No.KLIEEE-17-12)the High-level Innovation Team Overseas Training Project of Liaoning Provincial(No.201818)
文摘Antibiotics are widespread in various environmental media,and may pose a potential threat to aquatic ecosystems and non-target aquatic organisms.Florfenicol(FLO)is one of the most commonly used antibiotics in aquaculture,and extensively used to substitute chloramphenicol with its strong sterilization and low adverse ef fect.In this study,flounder Paralichthys olivaceus,an important economic fish species in seawater was used as an experimental subject.Five exposure concentrations of FLO(including environmentrelated concentrations)were set at 0,0.01,0.1,1,and 10 mg/L.Ef fects of FLO exposure for 168 h on growth and development,motor behavior,antioxidant enzyme activity,malondialdehyde(MDA)content,and thyroid hormone level of P.olivaceus larvae were studied in pre-larvae(1 dpf)and post-larvae(20 dpf).The results show that the short-term FLO exposure could promote the larvae growth to some degrees,but inhibit them as the exposure time prolonged.For pre-larvae,FLO at 0.01 mg/L could stimulate the motor nerve system and increase the swimming ability,but inhibited it at 1 mg/L.With the increasing dosage of FLO,the superoxide dismutase(SOD)and MDA contents were elevated,reaching the maximum in the 1 mg/L FLO group.The pre-larvae were more sensitive than the post-larvae to FLO in the environment,and the growth and immune resistance could be damaged with long exposure.Post-larvae were more tolerant to external pollutants,FLO at 1 mg/L could promote the motor behavior and reduce SOD and MDA contents.Therefore,FLO can be used as an antibiotic at a proper concentration but as a drug to prevent disease in a long-term way.
文摘The survival rates of shrimp larvae in different stage are higher than those of control groups when probiotic bacteria strains X4B 1 and X1B 1 which are isolated from gut of adult shrimp are added into the little volume rearing sea water of shrimp larvae. The effects of probiotic bacteria are evaluated by challenge test (pathogenic bacteria Z 3G 2 isolated from disease shrimp larvae in the hatchery of Jimo town) and low salinity stress resistance tests on shrimp larvae, the survival rate and lengths of the shrimp larvae in the experiment are determined. Results indicate that 1. The survival rate, ability of resistant to low salinity, lengths of the delivered shrimp larvae are improved after the strains of probiotic bacteria, X4B 1 or X1B 1, are added into the rearing sea water of hatchery. 2. The addition of the probiotic bacteria could not influence the change of the bacteria number, NH3 N and COD value in the rearing sea water. 3. The probiotic bacteria used in the experiment have many enzymes such as Lipase, Amylase, Gelatinase and Lecithinase. These enzymes may help the probiotic bacteria to digest the food components fed to shrimp larvae and increase the digestive efficiency of post larvae. This may be one of the reasons why these probiotic bacteria are beneficial to the shrimp larvae.
文摘This study evaluated efficacy of maternal and larval immunisation against Lactococcus garviae infection and on the lysozyme and immunoglobulin (IgM) levels in rainbow trout Oncorhynchus mykiss (Walaum). Forty-eight-day-old larvae (mean weight 96 mg) originating from injected weekly with letrozole and immunised, only immunised and non-immunised parents were experimentally infected with the L. garvieae, and the mortality rate was recorded daily. Larvae were vaccinated by immersion at 58 days post hatch with live L. garvieae (109 cells/mL) for 15 min. Every third day post larvae vaccination, two larvae from each group were collected for analysis lysozyme (by a method based on the ability of lysozyme to lyse the bacterium Micrococcus lysodeikticus) and IgM (by enzyme-linked immunosorbent assay (ELISA)) parameters. Vaccinated and control larvae were tested for protection against L. garvieae 30 days post larvae immunization when the larvae were 88 days old. Larvae were challenged by bath exposure with live L. garvieae (109 cells/mL) for 2 min and monitored for mortality for at least 10 days following challenge. The challenge experiment with L. garvieae showed a significant reduction in larvae from immunised (54.44% ± 0.64%) and injected weekly with letrozole and immunised fish (52.96% ± 0.97%) compared to larvae from control fish (62.96% ± 2.22%). Vaccinated larvae originated from injected weekly with letrozole and immunised parents showed significantly higher lysozyme activity compared to other fish groups. Vaccinated larvae showed significantly less mortality compared to controls. The relative percent survival (RPS) values of larvae from only immunised, injected weekly with letrozole and immunised and non-immunised parents vaccinated with L. garvieae were 67.36% ± 0.9%, 68.05% ± 0.66% and 48.27% ± 2.79% respectively. The results indicate that the effect of maternal immunization rainbow trout against L. garvieae infection by eliciting the immune responses as indicated by an increase in the IgM level and lysozyme activity.
基金Supported by the National Key R&D Program of China(Nos.2019YFD0901202,2018YFD0900905)the China Postdoctoral Science Foundation(No.2018M632887)。
文摘Fish populations have declined in many estuarine and freshwater ecosystems in part due to the loss of habitat in recent decades.Reconstructing lost habitat for larvae fish is a potential method for recovering larvae fish populations.Three-dimensional artificial floating wetlands(AFWs)on which Phragmites australis was planted were experimentally deployed to recover the lost habitat in the Changjiang(Yangtze)River estuary from May to July 2018.The AFW area was characterized by slow velocity,high transparency,low dissolved oxygen,and relatively constant water temperature.The total individuals of larvae fish in the AFW area(12122 in total)was higher than that in the non-AFW area(1250 in total),and the densities of most larvae fish species were higher in the AFW habitat than in the non-AFW area.The distributions of larvae fish species were positively influenced by habitat type because they were strongly related to the negative part of the first axis of the redundancy analysis,and Cyprinus carpio and Cyprinus auratus were inclined to habitat in the slow velocity and high transparency AFW habitat area.These results indicate that larvae fish species are inclined to inhabit the AFW habitat.The use of three-dimensional P.australis AFWs would be a potential method for enhancing the habitat of larvae fish in the degraded habitats along the estuary.
文摘For centuries, insects have been used as food due to their availability and easiness in raising that is much less burdensome for environment than animal husbandry breeding. Mealworm (Tenebrio molitor L.) is a store-pest of which larvae are consumed by people. The aim of the work was to determine the nutritional value of larvae of mealworm (Tenebrio molitor L.). The material was a three-month-old mealworm larva 25 -30 mmin length. Larvae were boiled for 3 min and next dried in 60℃. Contents of water, ash, minerals, protein, fat and fat acids profile have been determined. Fresh larvae contained 56% of water, 18% of total protein, 22% of total fat and 1.55% of ash. High contents of minerals were found in the larvae: magnesium (87.5 mg/100g), zinc (4.2 mg/100g), iron (3.8 mg/100g), copper (0.78 mg/100g) and manganese (0.44 mg/100g). The proportion of n-6/n-3 fatty acids was very advantageous and amounted to 6.76. Larvae powder contained twice higher content of protein, fat, ash and minerals. Larva of mealworm is a valuable source of nutrients in amounts more profitable for human organism than traditional meat food. Powdered larva is a high-grade product to be applied as a supplement to traditional meals.
文摘This study showed Iethal concentrations (LC) of copper for Peneaus penicillatus at various stages ofits Iife cycle were 1000μg/L for nauplii, 1000μg/L for Zoea I, 2000μg/L for Zoea Il, 2500μg/Lfor Zoea III, 3000μg/L for Mysis I, II and III and that for almost 100% mortality for postlarvae was3000μg/L. For cadmium LC were 100μg/L for nauplii, 500μg/L for Zoea l, 1000μg/L forZoea II, 2000μg/L for Zoea III, 2500μg/L for Mysis I and 3500μg/L for Mysis II, III andpostlarvae. For tmixture of both metals, LC were 400μg/L for nauplii, 1000 μg/L for nauplii, 1000μg/L for Zoea I,2000μg/L for Zoea II and 3000μg/L for Mysis I, II, III and post larvae.
