Healthy Larvae Research Articles

Staphylococcus saprophyticus is a pathogen of the cattle tick Rhipicephalus (Boophilus) microplus

During experimental Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) infestation on cattle, approximately 5% of engorged female ticks showed symptoms of bacterial infection. The affected ticks were unable to oviposit, secreted a distinctive yellow exudate through the genital orifice and eventually died. Microscopic analysis of tick exudate showed abundant clusters of Gram-positive cocci bacteria that were isolated and cultured on bacteriological medium. Biochemical phenotyping and 16S rRNA ribotyping analysis on cultured bacteria identified it as Staphylococcus saprophyticus. This species was also isolated from healthy tick larvae, indicating that S. saprophyticus is commonly found in ticks during different developmental stages. However, conspicuous symptoms are only found on fully engorged females. Cultured S. saprophyticus induced identical pathological symptoms when the bacteria were experimentally inoculated into healthy ticks, demonstrating it to be the causative agent of the R. microplus infectious lethal disease described in this work.

An in vivo RNA interference screen identifies gene networks controlling Drosophila melanogaster blood cell homeostasis.

BackgroundIn metazoans, the hematopoietic system plays a key role both in normal development and in defense of the organism. In Drosophila, the cellular immune response involves three types of blood cells: plasmatocytes, crystal cells and lamellocytes. This last cell type is barely present in healthy larvae, but its production is strongly induced upon wasp parasitization or in mutant contexts affecting larval blood cell homeostasis. Notably, several zygotic mutations leading to melanotic mass (or "tumor") formation in larvae have been associated to the deregulated differentiation of lamellocytes. To gain further insights into the gene regulatory network and the mechanisms controlling larval blood cell homeostasis, we conducted a tissue-specific loss of function screen using hemocyte-specific Gal4 drivers and UAS-dsRNA transgenic lines.ResultsBy targeting around 10% of the Drosophila genes, this in vivo RNA interference screen allowed us to recover 59 melanotic tumor suppressor genes. In line with previous studies, we show that melanotic tumor formation is associated with the precocious differentiation of stem-cell like blood progenitors in the larval hematopoietic organ (the lymph gland) and the spurious differentiation of lamellocytes. We also find that melanotic tumor formation can be elicited by defects either in the fat body, the embryo-derived hemocytes or the lymph gland. In addition, we provide a definitive confirmation that lymph gland is not the only source of lamellocytes as embryo-derived plasmatocytes can differentiate into lamellocytes either upon wasp infection or upon loss of function of the Friend of GATA cofactor U-shaped.ConclusionsIn this study, we identify 55 genes whose function had not been linked to blood cell development or function before in Drosophila. Moreover our analyses reveal an unanticipated plasticity of embryo-derived plasmatocytes, thereby shedding new light on blood cell lineage relationship, and pinpoint the Friend of GATA transcription cofactor U-shaped as a key regulator of the plasmatocyte to lamellocyte transformation.

Compatibility of Heterorhabditis indica (Rhabditida: Heterorhabditidae) and Habrobracon hebetor (Hymenoptera: Braconidae) for biological control of Plodia interpunctella (Lepidoptera: Pyralidae)

The potential for integrating the application of Heterorhabditis indica Poinar, Karunakar, and David (Homl strain) and release of Habrobracon hebetor (Say) in the management of the Indianmeal moth, Plodia interpunctella (Hübner), was investigated in the laboratory. A combination of the nematode and the parasitoid was observed to increase the mortality of P. interpunctella. The interaction between the nematodes and parasitoids was not antagonistic but could possibly be additive or synergistic. Release of parasitoids or application of nematodes alone generated between 62.25% and 71.25% mortality of the P. interpunctella larvae whereas combination of the two resulted in 98.0–99.25% mortality. The nematode was found to be virulent to the larvae of the parasitoid but not to the pupae and the adults. Adult female parasitoids that were exposed to both uninfected and nematode-infected P. interpunctella larvae in a free-choice arena were unable to distinguish between the two. In contrast, infective juvenile nematodes preferentially infected parasitized host larvae compared with healthy non-parasitized host larvae. Nematode reproduction was not significantly different in parasitized and non-parasitized host larvae. The combined application of H. indica and H. hebetor for the control of P. interpunctella may be beneficial if the detrimental effects of the nematode on the parasitoid can be minimized through optimum timing.

Differential host growth regulation by the solitary endoparasitoid, Meteorus pulchricornis in two hosts of greatly differing mass

Solitary koinobiont endoparasitoids generally reduce the growth of their hosts by a significant amount compared with healthy larvae. Here, we compared the development and host usage strategies of the solitary koinobiont endoparasitoid, Meteorus pulchricornis, when developing in larvae of a large host species ( Mythimna separata) and a much smaller host species ( Plutella xylostella). Caterpillars of M. separata were parasitized as L2 and P. xylostella as L3, when they weighed approximately 2 mg. The growth of parasitized M. separata larvae was reduced by almost 95% compared with controls, whereas parasitized P. xylostella larvae grew some 30% larger than controls. Still, adult wasps emerging from M. separata larvae were almost twice as large as wasps emerging from P. xylostella larvae, had larger egg loads after 5 days and produced more progeny. Survival to eclosion was also higher on M. separata than on P. xylostella, although parasitoids developed significantly faster when developing on P. xylostella. Our results provide evidence that koinobionts are able to differentially regulate the growth of different host species. However, there are clearly also limitations in the ability of parasitoids to regulate phenotypic host traits when size differences between different host species are as extreme as demonstrated here.

The Use of Eugenol as an Anesthetic in Transportation of With Indian Shrimp (Fenneropenaeus indicus) Post Larvae

The safe margin of eugenol for sedation of the healthy post larvae (PL) of white Indian shrimp (Fenneropenaeus indicus) was determined by estimating the median lethal concentration of eugenol during 24 hours (24hLC50). Sedation concentration of eugenol was obtained experimentally by considering behavioral factors of PLs such as response to indirect stimuli and changes in water quality parameters. Applying the estimated concentrations of eugenol for 12 hours transportation of PLs, biometric parameters of sedated animals were compared with the control after 96 hours post transportation at P<0.05. The 24hLC50 of eugenol for experimental PLs was found to be 5.2 mg/l with minimum confidence limit of 5.0 mg/L and maximum confidence limit of 5.3 mg/L. The sedation concentrations for PLs varied from a minimum level of 1.3 mg/L to a maximum level of 3.7 mg/L. During 24 hours sedation, significant reductions were found in the oxygen consumption of PLs where as no significant changes occurred in their ammonia secretion. There was no change in biometric parameters in sedated animals after 12 hours transportation. The results indicate that eugenol can be used as a sedative during transportation of PLs of F. indicus and concentration of 1.3 mg/L considered is safe which showed the lowest induction of bottom sitting.

KARAKTER PROTEIN ICP11 PADA DNA UDANG VANNAMEI (Penaeus vannamei) YANG TERINFEKSI White Spot Syndrome Virus (WSS V)

The aim of this study was to support policy of government to lessen import and improve export of non migas presented characteristic of genetic of white prawn mains (Penaeus vannamei) so that this product can be yielded in Indonesia with high quality which do not fail with import product. Special goals wishing to be reached at this research is to analyze the genetic characteristic DNA with Polymorphism Chain Reaction (PCR) and primer ICP11. The background of this research was difference among vannamei prawn DNA characteristic that have infected by viruses. With experimental methods ten healthy post larva of white prawn cultured in aquarium and invected by WSSV virus in 1ml/10 l marine water dossage with three time replication during 7 days in culture. To know these infection, the sample were analyze with specific primer ICP11.

Entomopathogenic fungi disturbed the larval growth and feeding performance of Ocinara varians (Lepidoptera: Bombycidae) larvae

Abstract Feeding experiments using three strains of entomopathogenic fungi, Beauveria bassiana, Metarhizium anisopliae and Isaria fumosorosea were conducted with newly moulted 3rd–5th instar Ocinara varians Walker larvae in the laboratory. The mortality of larvae immersed individually in spore suspension (1 × 107 spores/mL) of all the strains was ≥ 80% except 5th instar larvae treated with M. anisopliae which transformed into pupae, but did not result in adult emergence. The growth (total body mass), consumption, relative consumption rate and relative growth rate, were reduced at all three larval stages, while developmental time was extended in infected larvae with concurrent significant increase in approximate digestibility in infected larvae. Conversion of digested food (ECD) and ingested food (ECI) values declined in infected larvae as compared to the healthy larvae (control). The 5th instar larvae treated with M. anisopliae showed higher ECD and ECI values than control. Based on mortality and growth inhibition it can be suggested that all the studied fungal strains have a high potential for biocontrol and could be developed into biocontrol agents against O. varians.

Effects of an ascovirus (HvAV-3e) on diamondback moth, Plutella xylostella, and evidence for virus transmission by a larval parasitoid

Ascoviruses (AVs) are pathogenic to lepidopteran larvae, and most commonly attack species in the Noctuidae. The unique pathology includes cleavage of host cells into virion-containing vesicles which leads to the milky white colouration of the hemolymph as opposed to the clear hemolymph of healthy larvae. Recently, we showed that a Heliothis virescens AV (HvAV-3e) isolate is able to induce disease in Crocidolomia pavonana F. (Lepidoptera: Crambidae), affecting feeding, growth and survival of infected larvae. In this study, we investigated the effect of different variants of HvAV-3e on diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae) larvae, another non-noctuid host. In hemolymph inoculation bioassays fourth instar larvae showed a significant dose response to each of the HvAV-3e variants and significant differences between the virulence of the three variants were detected. Both second and fourth instars were readily infected with the virus and infected individuals demonstrated significant reductions in food consumption and growth. The majority of infected individuals died at the larval or pupal stage and individuals which developed into adults were usually deformed, less fecund than non-infected controls and died shortly after emergence. In transmission studies, Diadegmasemiclausum (Hymenoptera: Ichneumonidae), a key parasitoid of diamondback moth, infected healthy host larvae during oviposition following previous attack of HvAV-3e infected hosts. In choice tests D. semiclausum did not discriminate between infected individuals but host infection had no detectable impact on the development of immature D. semiclausum or on subsequent adults.

Genes related to immunity, as expressed in the alfalfa leafcutting bee, Megachile rotundata, during pathogen challenge

Virtually nothing is known about disease resistance in solitary bees, so expressed sequence tag (EST) databases were developed to search for immune response genes in the alfalfa leafcutting bee. We identified 104 putative immunity-related genes from both healthy and pathogen-challenged bee larvae, and 12 more genes using PCR amplification. The genes identified coded for proteins with a wide variety of innate immune response functions, including pathogen recognition, phagocytosis, the prophenoloxidase cascade, melanization, coagulation and several signalling pathways. Some immune response genes were highly conserved with honey bee genes, and more distantly related to other insects. The data presented provides the first analysis of immune function in a solitary bee and provides a foundation for the further analysis of gene expression patterns in bees.

Odorants that Induce Hygienic Behavior in Honeybees: Identification of Volatile Compounds in Chalkbrood-Infected Honeybee Larvae

Social insects that live in large colonies are vulnerable to disease transmission due to relatively high genetic relatedness among individuals and high rates of contact within and across generations. While individual insects rely on innate immune responses, groups of individuals also have evolved social immunity. Hygienic behavior, in which individual honeybees detect chemical stimuli from diseased larvae and subsequently remove the diseased brood from the nest, is one type of social immunity that reduces pathogen transmission. Three volatile compounds, collected from larvae infected with the fungal pathogen Ascosphaera apis and detected by adult honey bees, were identified by coupled gas chromatography-electroantennographic detection and gas chromatography-mass spectrometry. These three compounds, phenethyl acetate, 2-phenylethanol, and benzyl alcohol, were present in volatile collections from infected larvae but were absent from collections from healthy larvae. Two field bioassays revealed that one of the compounds, phenethyl acetate is a key compound associated with Ascosphaera apis-infected larvae that induces hygienic behavior.

The innate immune and systemic response in honey bees to a bacterial pathogen, Paenibacillus larvae

BackgroundThere is a major paradox in our understanding of honey bee immunity: the high population density in a bee colony implies a high rate of disease transmission among individuals, yet bees are predicted to express only two-thirds as many immunity genes as solitary insects, e.g., mosquito or fruit fly. This suggests that the immune response in bees is subdued in favor of social immunity, yet some specific immune factors are up-regulated in response to infection. To explore the response to infection more broadly, we employ mass spectrometry-based proteomics in a quantitative analysis of honey bee larvae infected with the bacterium Paenibacillus larvae. Newly-eclosed bee larvae, in the second stage of their life cycle, are susceptible to this infection, but become progressively more resistant with age. We used this host-pathogen system to probe not only the role of the immune system in responding to a highly evolved infection, but also what other mechanisms might be employed in response to infection.ResultsUsing quantitative proteomics, we compared the hemolymph (insect blood) of five-day old healthy and infected honey bee larvae and found a strong up-regulation of some metabolic enzymes and chaperones, while royal jelly (food) and energy storage proteins were down-regulated. We also observed increased levels of the immune factors prophenoloxidase (proPO), lysozyme and the antimicrobial peptide hymenoptaecin. Furthermore, mass spectrometry evidence suggests that healthy larvae have significant levels of catalytically inactive proPO in the hemolymph that is proteolytically activated upon infection. Phenoloxidase (PO) enzyme activity was undetectable in one or two-day-old larvae and increased dramatically thereafter, paralleling very closely the age-related ability of larvae to resist infection.ConclusionWe propose a model for the host response to infection where energy stores and metabolic enzymes are regulated in concert with direct defensive measures, such as the massive enhancement of PO activity.

Phenotypic changes and the fate of digestive enzymes during induction of amber disease in larvae of the New Zealand grass grub ( Costelytra zealandica)

Amber disease of the New Zealand grass grub Costelytra zealandica (Coleoptera: Scarabaeidae) is caused by ingestion of pADAP plasmid carrying isolates of Serratia entomophila or Serratia proteamaculans (Enterobacteriaceae) and causes infected larvae to cease feeding and clear their midgut to a pale amber colour where midgut serine protease activities are virtually eliminated. Using bacterial strains and mutants expressing combinations of the anti-feeding ( afp) and gut clearance ( sep) gene clusters from pADAP, we manipulated the disease phenotype and demonstrated directly the relationship between gene clusters, phenotype and loss of enzyme activity. Treatment with afp-expressing strains caused cessation of feeding without gut clearance where midgut protease activity was maintained at levels similar to that of healthy larvae. Treatment with strains expressing sep-genes caused gut clearance followed by a virtual elimination of trypsin and chymotrypsin titre in the midgut indicating both the loss of pre-existing enzyme from the lumen and a failure to replenish enzyme levels in this region by secretion from the epithelium. Monitoring of enzymatic activity through the alimentary tract during expression of disease showed that loss of serine protease activity in the midgut was matched by a surge of protease activity in the hindgut and frass pellets, indicating a flushing and elimination of the midgut contents. The blocking of enzyme secretion through amber disease appears to be selective as leucine aminopeptidase and α-amylase were still detected in the midgut of diseased larvae.

Two pathogens of Greenshell™ mussel larvae, Perna canaliculus: Vibrio splendidus and a V. coralliilyticus/neptunius‐like isolate

Bacterial pathogens of Greenshell mussel (GSM) larvae can cause batch losses during hatchery production. Twenty-two isolates were screened using a larval bioassay. Two strains were identified as potential pathogens. Phenotypic identification of these strains revealed two non-reactive Gram-negative, oxidase positive rods. Sequencing of the 16S rRNA gene identified Vibrio splendidus and a V. coralliilyticus/neptunius-like isolate as pathogens of GSM larvae, with an ability to cause 83% and 75% larval mortality in vitro, respectively, at a concentration of 10(2) CFU mL(-1). Histopathology indicated that the route of infection was via the digestive system. Using healthy larvae as target hosts, Koch's postulates were confirmed for the two isolates. This is the first report on pathogens of GSM larvae.

THE EFFECT OF STARVATION ON FEEDING,GROWTH AND MORPHOLOGICAL DEVELOPMENT OF THE LARVAE OF MOSQUITO FISH

Mosquito fish Gambusia affinis is a small,ovoviviparous topminnow,native to the North America which had been an invasive species widely in the world.The larvae of this species were reared at about (28.5±1.2)℃ in laboratory to examine the feeding ability change,growth and morphological development under starvation condition to investigate their early recruitment potential fluctuation affected by starvation factor.All larvae were divided into 3 groups:unfed,feeding and mortality observation group,each group were reared in three 2.5L glass tanks.Every day 5 larvae were taken from the culture tanks of unfed or feeding group to measure the morphological indexes in microscope respectively,while 10 larvae were taken to examine feeding ratio and intensity.The dead larvae of mortality observation group were recorded and removed every day. The results showed that the new born larvae developed perfectly,swam and preyed freely after 2 hours when the swim bladder was filled with gas,and used the yolk-sac to provide energy about 6 hours.Their mixed-nutrient stage lasted only 4 hours.During the experiment,the feeding ratio of feeding larvae was 100% while unfed larvae had feeding ratio at 100% when re-fed from 0d to 3d following by decreasing rate.On the 5thd,feeding ratio of unfed larvae was remarkable lower than those of feeding larvae.On the 6thd,unfed larvae feeding ratio was 0.Feeding ratio of unfed larvae had negative relationship with starvation time.The new born larvae feeding intensity on 1—2 stage mosquito larvae was (2.9±1.4)ind/ind·h,which increasing rapidly,and each 6-d-born fish can capture more than 11 mosquito larvae.After re-feeding,unfed larvae feeding intensity increased with their age during 0—4d,but was very remarkable lower than those of feeding fish at the same age,and dropped on the 5thd.There were no remarkable relationship between initial feeding ratio and initial feeding intensity of unfed larvae.The-point-of-no-return (PNR) was 5.5 day of unfed larvae.The death rate of unfed larvae was lest than 10% on 0—3d,(64.4±18.1)% on 4d and 100% on 6d while feeding larvae was no more than 5%. At the 6th day after birth,the venter fins of feeding larvae developed and different part of the body had different growth rate.The body depth (BD) and weight (W) of unfed larvae performed remarkable negative growth rate.Standard body length (SL)/Body depth (BD) ratio was higher than 5 in unfed larvae while lower than 4.5 in feeding larvae,which can be applied to distinguish the starvation and healthy larvae in field research.The relationship between larvae starvation tolerance and competitive ability and their invasion were also discussed in this paper.

Analysis of bacterial populations in the gut of developing cod larvae and identification of Vibrio logei, Vibrio anguillarum and Vibrio splendidus as pathogens of cod larvae

Poor larval survival rates currently limit production in aquaculture and a better understanding of the bacterial flora in the larval digestive tract is essential to improving survival in hatchery reared larval fish. Identification of bacteria alone is insufficient, as the concentrations of key bacterial species may be important in determining survival. Here, we analysed bacteria, principally vibrios, in developing cod larvae from a Scottish hatchery. Six tanks of larvae were sampled weekly in parallel to monitor the microbial populations in larvae successively fed on rotifers and Artemia before weaning onto dry feed. When cod larvae were fed on rotifers the digestive tract microbiota was dominated by Ruegeria/Roseobacter, Pseudoalteromonas, and Microbacterium but when the diet was changed to Artemia over 90% of the microbiota consisted of vibrios. Polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) analysis was used to identify the vibrios present and this showed that the microbiota was affected by changes in larval diet. Whilst feeding on Artemia, the larval digestive tract microbiota was dominated by Vibrio alginolyticus, but the population rapidly switched to one dominated by V. splendidus when larvae were weaned onto dry feed. Other Vibrio species were detected at lower levels at various times. During the survey, one tank experienced heavy mortalities associated with an elevated level of Vibrio anguillarum. The V. anguillarum isolates differed from those typically associated with mortalities in gadoid fish. Apparently healthy larvae from the tank experiencing heavy mortalities had a culturable microbiota almost equally represented by V. anguillarum and V. logei. Both species, as well as a V. splendidus strain isolated from turbot larvae, were pathogenic to cod larvae in laboratory experiments, and these vibrios could be targets for intervention to control the microbial flora of the larval digestive tract.

Functional response of Orius albidipennis preying on healthy and Metarhizium anisopliae-infected larvae and adults of Thripstabaci

Functional response of Orius albidipennis preying on healthy and Metarhizium anisopliae-infected larvae and adults of Thripstabaci

Effects of water temperature on early development of Japanese eel Anguilla japonica

To determine an optimal temperature range for efficient production of healthy eel larvae Anguilla japonica, the effect of water temperature on hatching, survival, and deformity rates was examined. The early ontogeny of morphological features in this species by incubating eggs at five different temperatures (19, 22, 25, 28 and 31 °C) was examined. Hatching occurred at 24, 28, 46 and 58 h after fertilization when incubated at 28, 25, 22 and 19°C, respectively; no eggs hatched at 31°C The growth rate of prefeeding larvae increased as water temperature was elevated and acquisition of feeding ability was also accelerated at higher temperature. Significantly high hatching rates (76–86°, P<0.05) and survival rates (61–86%, P<0.05) were observed at relatively high temperatures (22–28°C). The deformities were ‘open lower jaw’, ‘pericardial edema’, and ‘notochordal bending’, in which the mouth was deformed with a downward projecting lower jaw, the pericardial cavity was swollen, and the notochord was bent or twisted to various degrees, respectively. Open lower jaw and pericardial edema were especially predominant at 19°C, with rates of 68 and 92%, respectively, compared with 31 and 10% at 25 and 28°C, respectively. The occurrence of notochordal bending was not affected by temperature. The optimal temperature for incubation and rearing A. japonica eggs and prefeeding larvae is approximately 25–28°C.

Drosophila haematopoiesis

Like in vertebrates, Drosophila haematopoiesis occurs in two waves. It gives rise to three types of haemocytes: plasmatocytes (phagocytosis), crystal cells (melanization) and lamellocytes (encapsulation of parasites). A first population of haemocytes, specified during embryogenesis, gives rise to an invariant number of plasmatocytes and crystal cells. A second population of haemocytes is specified during larval development in a specialized haematopoietic organ, the lymph gland. All three types of haemocytes can be specified in this organ, but lamellocytes only differentiate in response to parasitism. Thus, larval in contrast to embryonic haematopoiesis can be modulated by physiological constraints. Molecular cascades controlling embryonic haematopoiesis are relatively well established and require transactivators such as GATA, FOG and Runx factors, which are also co-opted in mammalian haematopoiesis. Mechanisms involved during larval haematopoiesis are less well understood although a number of chromatin remodelling factors and signalling pathways (JAK/STAT, Toll, Hedgehog, Notch) are required. In healthy larvae a pool of progenitors is maintained within the lymph gland, under the control of a signalling centre which expresses Collier, Serrate, Antennapedia and Hedgehog, and controls haemocyte homeostasis. Its key role in haemocyte homeostasis is reminiscent of interactions described in vertebrates between haematopoietic stem cells and their microenvironment (niche).

Drosophila Hemopoiesis and Cellular Immunity

In Drosophila melanogaster larvae, three classes of circulating cellular immune surveillance cells (hemocytes) can be identified: plasmatocytes, crystal cells, and lamellocytes. Plasmatocytes are professional phagocytes most similar to the mammalian monocyte/macrophage lineage and make up approximately 95% of circulating hemocytes. The other approximately 5% of circulating hemocytes consists of crystal cells, which secrete components necessary for the melanization of invading organisms, as well as for wound repair. A third cell type known as lamellocytes are rarely seen in healthy larvae and are involved in the encapsulation of invading pathogens. There are no obvious mammalian counterparts for crystal cells or lamellocytes, and there is no equivalent to the lymphoid lineage in insects. In this review, I will discuss what is currently known about Drosophila hemopoiesis and the cellular immune response and where possible compare it to vertebrate mechanisms.

Delivery of HUFA, probionts and biomedicine through bioencapsulated Artemia as a means to enhance the growth and survival and reduce the pathogenesity in shrimp Penaeus monodon postlarvae

One of the major problems in the shrimp culture industry is the difficulty in producing high-quality shrimp larvae. In larviculture, quality feeds containing a high content of highly unsaturated fatty acids (HUFA) and ingredients that stimulate stress and disease resistance are essential to produce healthy shrimp larvae. In the present study, Penaeus monodon postlarvae (PL15) were fed for 25 days on an unenriched Artemia diet (control; A) or on a diet of Artemia enriched with either HUFA-rich liver oil of the trash fish Odonus niger (B), probionts [Lactobacillus acidophilus (C1) or yeast-Saccharomyces cerevisiae (C2)] or biomedicinal herbal products (D) that have anti-stress, growth-promoting and anti-microbial characteristics. P. monodon postlarvae fed unenriched Artemia exhibited the lowest weight gain (227.9 ± 8.30 mg) and specific growth rate (9.95 ± 0.05%), while those fed the HUFA-enriched Artemia (B) exhibited the highest weight gain and specific growth rate (362.34 ± 12.56 mg and 11.77 ± 0.08%, respectively). At the end of the 25-day rearing experiment, the shrimp postlarvae (PL40) were subjected to a salinity stress study. At both low and high (0 and 50‰) salinities, the group fed the control diet (A) experienced the highest cumulative mortality indices (CMI) 935.7 ± 2.1 and 1270.7 ± 3.1, respectively. Those fed diet D showed the lowest stress-induced mortality, and CMI were reduced by 31.1 and 32.3% under conditions of low and high salinity stress, respectively. A 10-day disease challenge test was conducted with the P. monodon postlarvae (PL40–PL50) by inoculating the shrimp with the pathogen Vibrio harveyi at the rate of 105–107 CFU/ml in all rearing tanks. P. monodon postlarvae fed probiont-encapsulated Artemia diets (C1 and C2) exhibited the highest survival (94.3 and 82.3%, respectively) and lowest pathogen load (V. harveyi) in hepatopancreas (5.2 × 102 ± 9.0 × 10 and 4.6 × 102 ± 9.0 × 10 CFU g−1, respectively) and muscle (2.0 × 102 ± 6 × 10 and 1.7 × 102 ± 8.6 × 10 CFU g−1, respectively) tissues. The shrimp that were fed the unenriched Artemia (Control; A) showed the lowest survival (26.33%) and highest bacterial load in the hepatopancreas (1.0 × 105 ± 5 × 103 CFU g−1) and muscle (3.6 × 104 ± 6 × 102 CFU g−1). The shrimp fed the herbal product (D)-enriched Artemia also exhibited enhanced survival and reduced V. harveyi load in the tissues tested compared to the control diet (A) group. The results are discussed in terms of developing a quality larval feed to produce healthy shrimp larvae.