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At least 19 recordsLinked to original sources
PubMed2005

Use of broad-spectrum antimicrobials in the eradication of unknown aquatic pathogens in a zebrafish larval rearing system.

A zebrafish larval rearing system experienced a surge in mortality rates soon after the introduction of new stocks. A comprehensive water analysis of pH, nitrites, nitrates, ammonia, chlorine, carbonate hardness, general hardness, and conductivity identified no anomalies. Observations via light microscopy of affected fry revealed consistent signs of impaired mobility, blood clotting, and eventual heart hemorrhage resulting in the death of 90 to 100% of the fry by the age of 2 weeks. Collection of sufficient tissue samples for a histological investigation proved problematic due to the fry's diminutive size. Because a causal agent could not be isolated satisfactorily, the use of a broad-spectrum antibiotic was deemed necessary. After considering many broad-spectrum antibiotics for treatment, we implemented a two-tiered approach for treatment. The rearing system was treated with a nitrofurazone derivative, whereas the adult populations were treated using multi-antibiotic food pellets. The rearing system was treated for 3 weeks, and the adult population was treated for 2 weeks. After the completion of the antibiotic treatments, the biological filters of all of the medicated systems were seeded with nitrifying bacterial cultures. Upon the maturation of the rearing systems' biological filters, mortality rates returned to pre-outbreak levels. There have been no re-occurrences of the fish mortality since the completion of treatment. This epidemic provided some valuable lessons, lessons that if followed, will ensure faster response to unknown pathogens in the future.

Animal Feed↗
PubMed2005

Vibrio splendidus biotype 1 as a cause of mortalities in hatchery-reared larval turbot, Scophthalmus maximus (L.).

AIMS: To characterize bacteria associated with turbot larvae feeding on Artemia and identify pathogens causing mortalities in larvae. METHODS AND RESULTS: To identify bacteria associated with mortalities in larval turbot rearing, bacteria were isolated from homogenates of Artemia or from several batches of well-performing or poorly performing turbot larvae. Samples were plated onto marine agar and were characterized using biochemical tests and BIOLOG GN plates. Total culturable aerobic bacteria ranged from 1.9 x 10(5) to 1.8 x 10(6) CFU per larva and >96% of bacteria identified were vibrios. Almost all bacteria were haemolytic and clustered into two phenons represented by Vibrio alginolyticus and Vibrio splendidus. The bacterial flora of Artemia was almost entirely V. alginolyticus, whereas V. splendidus biotype 1 dominated the larval turbot gut flora (69/115 isolates in seven experiments) and formed four different groups based on BIOLOG GN reactions. Of 16 isolates tested for virulence towards turbot larvae, four of the 11 V. splendidus biotype 1 isolates were lethal and all belonged to the same group of V. splendidus biotype 1 isolates. CONCLUSIONS: In a commercial turbot hatchery, the microbial flora of the larval gut was dominated by V. splendidus biotype 1. Four of the 11 V. splendidus biotype 1 isolates caused mortalities in larval turbot and all belonged to one group of the biotype 1 strains identified. SIGNIFICANCE AND IMPACT OF THE STUDY: Identification of four isolates of V. splendidus that are pathogenic for turbot larvae from three separate batches of larval turbot will allow these to be compared with avirulent isolates to define how V. splendidus causes mortalities in larval turbot.

Animals↗
PubMed2002

Efficacy of water hyacinth compost in nursery ponds for larval rearing of Indian major carp, Labeo rohita.

The use of water hyacinth compost as manure in nursery ponds for larval rearing of Indian major carp, Labeo rohita was studied. Better performance with regard to growth and survivability of the larvae was recorded in the ponds treated with water hyacinth compost (Group A) than in either the ponds treated with inorganic fertilizers (Group B) or the ponds where no treatment was applied (Group C). The average percentages of survival in Groups A, B and C were 14.3, 11.2 and 5.0, respectively. Thus about 186% increase in the survivability was recorded in the ponds treated with water hyacinth compost (P < 0.01), whereas the increase was about 124% in the ponds treated with only inorganic fertilizers, when compared with the ponds which were without any treatment.

Animals↗
PubMed1998

Effect of salt concentration in larval rearing water on susceptibility of Aedes Mosquitoes (Diptera: Culicidae) to eastern equine and Venezuelan equine encephalitis viruses.

The effect of salt concentration in larval rearing water on the susceptibility of adult Aedes taeniorhynchus (Wiedemann) and Aedes sollicitans (Skuse) to infection with eastern equine encephalomyelitis (EEE) virus was tested in the laboratory. Ae. sollicitans was more susceptible to infection (79%, n = 82) and viral dissemination (16%) with EEE virus than was Ae. taeniorhynchus (42%, n = 184) and (5%), respectively, when fed on a chick with a viremia of 10(7) +/- 0.1 plaque-forming units/ml; however, infection rates in adults were not affected by rearing in salt concentrations ranging from fresh water to brackish water containing 2.4% sea salts (1 part fresh water and 2 parts seawater). When fed on the same viremic 6-d-old chicken, all 48 Aedes albopictus (Skuse), reared in fresh water, became infected. Similarly, Venezuelan equine encephalitis viral infection or dissemination rates did not vary among Ae. taeniorhynchus adults that were reared in water containing 0, 1, or 2% sea salts.

Aedes↗
PubMed1996

Larval rearing temperature affects morphology of Anopheles albimanus (Diptera:Culicidae) male genitalia.

The structure of the male genitalia of Anopheles albimanus Wied. is affected by larval rearing temperature. Morphometric analyses of 50 specimens revealed significant variation of 5 genitalic characters. The gonocoxa, dorsal claspette lobes, and aedeagus were longer for males reared at 22 degrees C. The parabasal seta was longer and the aedeagus was wider for males reared at 30 degrees C. Extra parabasal setae and lateral projections of the aedeagus were seen on some specimens.

Animals↗
PubMed1998

Larval rearing water and preexisting eggs influence oviposition by Aedes aegypti and Ae. albopictus (Diptera: Culicidae).

Two-choice laboratory bioassays were used to evaluate oviposition responses of gravid Aedes aegypti (L.) and Ae. albopictus (Skuse) to larval rearing water and eggs from prior egg deposition. Oviposition responses by female Ae. aegypti were similar between larval water from Ae. aegypti and water controls but significantly greater to larval water from Ae. albopictus (12.2%) compared with water controls. Oviposition by Ae. albopictus females increased significantly in response to larval water from either species compared with water controls with increases of 15.1% to Ae. aegypti larval water and 17.6% to Ae. albopictus larval water. Oviposition responses of gravid Ae. aegypti and Ae. albopictus were evaluated in the presence of preexisting conspecific and heterospecific eggs on strips of oviposition paper. Significantly more eggs were laid by gravid Ae. aegypti females on oviposition paper containing either Ae. aegypti or Ae. albopictus eggs than on oviposition paper without eggs. In contrast, oviposition responses of gravid Ae. albopictus females were unaffected by the presence of eggs of either species.

Aedes↗
PubMed2005

Antimicrobial activity of chitosan against vibrios from freshwater prawn Macrobrachium rosenbergii larval rearing systems.

Chitosan is a biocompatible and biodegradable natural polymer with established antimicrobial properties against specific microorganisms. The present study demonstrates its antibacterial activity against 48 isolates of Vibrio species from prawn larval rearing systems. The antibacterial activity had a positive correlation with the concentration of chitosan. This work opens up avenues for using chitosan as a prophylactic biopolymer for protecting prawn larvae from vibriosis.

Animals↗
PubMed2005

A marine bacterium, Micrococcus MCCB 104, antagonistic to vibrios in prawn larval rearing systems.

A marine bacterium, Micrococcus MCCB 104, isolated from hatchery water, demonstrated extracellular antagonistic properties against Vibrio alginolyticus, V. parahaemolyticus, V. vulnificus, V. fluviallis, V. nereis, V. proteolyticus, V. mediterranei, V cholerae and Aeromonas sp., bacteria associated with Macrobrachium rosenbergii larval rearing systems. The isolate inhibited the growth of V. alginolyticus during co-culture. The antagonistic component of the extracellular product was heat-stable and insensitive to proteases, lipase, catalase and alpha-amylase. Micrococcus MCCB 104 was demonstrated to be non-pathogenic to M. rosenbergii larvae.

Animals↗
PubMed2006

Premating isolation is determined by larval rearing substrates in cactophilic Drosophila mojavensis. VII. Effects of larval dietary fatty acids on adult epicuticular hydrocarbons.

Low concentrations of dietary triacylglycerols including tristearin, triolein, and tripalmitolein, were assessed to determine their effects during egg to pupal stages on adult epicuticular hydrocarbon (EHC) variation in cactophilic Drosophila mojavensis. Triacylglycerols were added singly and in combination at concentrations of 1%, 3%, and 9% to a lipid-free culture medium. Control diets included Carolina Drosophila and lipid-free media. Egg to adult viability was reduced at triacylglycerol concentrations greater than 1%, except for tristearin. Both triolein and tripalmitolein increased EHC amounts to levels similar to those in combination and control diets. Tristearin caused significantly lower quantities of EHCs in adult flies than triolein or tripalmitolein, consistent with previous studies on reduced tristearin assimilation into adult EHCs. We rejected the hypothesis that unsaturated and saturated triacylglycerols were assimilated into unsaturated and saturated adult EHCs, respectively. Since these triacylglycerols comprise a fraction of known lipids in the columnar cacti used for breeding in nature, and EHCs serve as contact pheromones in D. mojavensis, these and other naturally occurring triacylglycerols may provide a direct causal link between host plant use and patterns of chemically mediated mate choice.

Animals↗
PubMedDate not supplied

Biochemical composition and fatty acid content of zooplankton from tropical lagoon for larval rearing.

Zooplankton samples were collected from the indigenous tropical brackish water lagoon during the wet monsoon (January and February 1990) and the dry monsoon (April and May 1990). The dominant copepod species in the zooplankton community comprising of Oithona sp (especially O. nana and O. robusta) accounted for more than 70% of the zooplankton in January and was gradually replaced by other zooplanktonic species later in the dry season. The lipid contents in zooplankton varied from 0.18 to 1.04% wet weight or 1.14 to 5.92% dry weight respectively. The major fatty acid contents of the zooplankton showed high concentration of 14:0, 16:0, 18:1, 20:5 omega 3 and 22:6 omega 3 especially in the wet season. It also contained high omega-3 highly unsaturated fatty acid series necessary for the growth of commercial fish larvae. It has a better food value than the normally use food organism, brine shrimp; thus reflecting its potential use as food organism for fish larval rearing.

Animal Feed↗
PubMed2003

Novel growth media for rearing larval horn flies, Haematobia irritans (Diptera: Muscidae).

Experiments were conducted to develop an agar-based medium for rearing immature horn flies, Hematobia irritans (L.). Larval survival was determined on sterilized manure inoculated with pure and mixed cultures of Acinetobacter sp., Bacillus pumilus Meyer & Gottheil, Comamonas acidovorans den Dooren de Jong, Pseudomonas mendocina Palleroni, Flavobacterium sp. and Empedobacter breve (Holmes & Owen). Rearing larvae on mixed cultures enhanced pupal weight but not survival. Horn fly larvae failed to survive when reared on standard bacteriological media inoculated with pure and mixed cultures of Acinetobacter sp., P. mendocina, and C. acidovorans. Larvae completed development on a minimal medium supplemented with alfalfa, egg proteins, and vitamins. Medium with low alfalfa content (30 g alfalfa/500 ml minimal medium) had enhanced survival when supplemented with egg yolk protein and vitamins. Medium with high alfalfa content (130 g alfalfa/500 ml minimal medium) had enhanced survival when supplemented with whole egg protein and vitamins. Survival was also favored when media were inoculated with pure cultures of Acinetobacter or Acinetobacter mixed with either Pseudomonas or Comamonas. Individual plates could support larvae developing from up to 40 eggs, and survival was least variable when plates were inoculated with greater numbers of eggs. This rearing system shows promise as a means for conducting standardized bioassays on a meridic diet.

Animals↗
PubMed2004

Strain-specific quantification of Wolbachia density in Aedes albopictus and effects of larval rearing conditions.

The density of the endosymbiont Wolbachia can influence the expression of the crossing sterilities known as cytoplasmic incompatibility (CI), and also its rate of maternal transmission. Aedes albopictus mosquitoes contain a superinfection with the Wolbachia strains wAlbA and wAlbB. A strain-specific real-time quantitative PCR assay was developed and used to quantify relative Wolbachia strain densities within individual mosquitoes. The wAlbB strain was consistently found to be at higher density than wAlbA, which can explain a slightly lower rate of maternal transmission reported for wAlbA. The effects of larval crowding and nutritional stress were also examined. Larval crowding always reduced adult size, but reduced the density of Wolbachia strains relative to uncrowded conditions only if crowding was accompanied by restricted nutrient availability. Crowded rearing conditions never resulted in strain segregation or in a reduction in the penetrance of CI, however. The rate of maternal transmission and the penetrance of CI are the two most important variables that determine relative Wolbachia population invasion dynamics, and both are considerably higher here than have been reported in the Drosophila simulans model system.

Aedes↗
PubMed1991

The initial establishment of sandfly colonies.

The initiation of laboratory colonies of phlebotomine sandflies is far more difficult than the maintenance of already established colonies. Based on our experience of setting up more than two dozen colonies, we present an account of the methods which we have found most successful. They include: techniques for collection and feeding wild-caught females: transportation in the field: optimum conditions for oviposition: choice and preparation of larval-rearing pots: larval food: handling adults: and the influence of cage size for sandfly copulation in the laboratory.

Animals↗
PubMed2003

Role of bacteria in mediating the oviposition responses of Aedes albopictus (Diptera: Culicidae).

The responses of Aedes albopictus to sources of oviposition attractants and stimulants were evaluated with a behavioral bioassay in which females attracted to odorants emanating from water were trapped on screens coated with an adhesive. Gravid mosquitoes were attracted to volatiles from larval-rearing water and soil-contaminated cotton towels. Bacteria were isolated from these substrates and from an organic infusion made with oak leaves. Through fatty acid-methyl ester analyses, six bacterial isolates from larval-rearing water, two isolates from soil-contaminated cotton towels, and three isolates from oak leaf infusion were identified to species. The response of gravid mosquitoes to these isolates was also evaluated in behavioral bioassays. Water containing Psychrobacter immobilis (from larval-rearing water), Sphingobacterium multivorum (from soil-contaminated cotton towels), and an undetermined Bacillus species (from oak leaf infusion) elicited significantly higher oviposition than control water without bacteria. Only volatiles collected from larval rearing water elicited significant electroantennogram responses in females.

Aedes↗
PubMed2000

Physiological aspects of multiple blood feeding in the malaria vector Anopheles tessellatus.

The malaria vector Anopheles tessellatus is able to take several blood meals in a gonotrophic cycle. The fecundity is largely dependent on the first blood meal and is not generally increased by subsequent blood meals during a gonotrophic cycle. Larval rearing densities influenced adult body size. There is an inverse relationship between wing length and larval rearing densities. Smaller mosquitoes produced from larvae reared at higher densities had reduced body reserves of protein, lipid and carbohydrates. At emergence, ovarian development in An. tessellatus is in the previtellogenic stage and it remained at this stage until the intake of a blood meal. The number of ovarian follicles is related to wing length and, irrespective of adult body size, An. tessellatus developed oocytes to maturity with a single blood meal. This is attributed to the availability of metabolic reserves above the threshold level required for further development of oocytes. Mosquitoes that took more than one blood meal had largely digested their previous blood meal and had ongoing vitellogenesis. Blood meals subsequent to the first one apparently contribute mainly to increasing metabolic reserves. The stimulus for a second and third blood meal in An. tessellatus appears to be completion of the digestion of the previous blood meal. There was no evidence that multiple blood meals taken in the first gonotrophic cycle influenced fecundity significantly in the second cycle.

Journal Article↗