Live Larvae Research Articles

Effects of pen enrichment on leg health of fast and slower-growing broiler chickens

Pen enrichment for broiler chickens is one of the potential strategies to stimulate locomotion and consequently contribute to better leg health and welfare. This study was designed to evaluate effects of using a plethora of pen enrichments (barrier perches, angular ramps, horizontal platforms, large distance between feed and water and providing live Black Soldier fly larvae in a dustbathing area) on tibia characteristics, locomotion, leg health and home pen behaviour of fast and slower-growing broiler chickens. The experiment was set up as a 2 x 2 factorial arrangement with a total of 840 male broiler chickens in a complete randomized design (7 pens per treatment and 30 chickens per pen) with the following treatments: 1) pen enrichment (enriched pen or non-enriched pen); 2) broiler strain (fast-growing Ross 308 or slower-growing Hubbard JA 757). Home pen behaviour and use of enrichment were observed. At approximately 1400 and 2200 g body weight, two chickens per pen were randomly selected and slaughtered, to investigate tibia morphological, biophysical and mechanical characteristics and leg health. Pen enrichment positively affected tibia biophysical characteristics, e.g., osseous volume (Δ = 1.8 cm3, P = 0.003), total volume (Δ = 1.4 cm3, P = 0.03) and volume fraction (Δ = 0.02%, P = 0.002), in both fast and slower-growing chickens, suggesting that pen enrichment particularly affects ossification and mineralization mechanisms. Accordingly, locomotion and active behaviours were positively influenced by pen enrichment. However, pen enrichment resulted in lower body weight gain in both strains, which might be due to higher activity or lower feed intake as a result of difficulties of crossing the barrier perches. Regarding the strain, slower-growing chickens showed consistently more advanced tibia characteristics and more active behaviour than fast-growing chickens. It can be concluded that pen enrichment may lead to more activity and better bone development in both fast and slower-growing chickens.

Impacts of macrocyclic lactones on larval survival, growth and development of three dung beetle species (Coleoptera: Scarabaeidae)

AbstractMacrocyclic lactones (MLs) are some of the most pervasive chemicals used in cattle management to control internal parasites. However, the drenches can have a range of lethal and sublethal impacts, potentially impacting the efficiency of adult dung beetles at burying dung and negatively impacting their larval growth, development and survival. Here, we assess the impacts of adult dung beetles provisioning their larvae with cattle faecal residues containing three commonly used cattle drenches in Australia – moxidectin, abamectin and doramectin. We used the larvae of two introduced tunnelling (paracoprid) species: Onthophagus binodis and Onitis viridulus, and one introduced rolling (telecoprid) species: Sisyphus rubrus. We anticipated that dung beetle larvae feeding on dung containing an ML would have altered growth patterns to those larvae feeding on untreated dung. Further, beetle larvae exposed to an ML in the dung would have different growth patterns, depending on the time the chemical took to be excreted from the treated cattle, with the anticipation that the chemical may have a peak excretion time. We also expected that dung beetle larvae feeding on dung containing an ML would have a decreased survival rate compared to dung beetle larvae feeding on untreated dung. We found that abamectin and doramectin were more toxic to beetle larvae than moxidectin and control dung, across all three species, and these chemicals also had the greatest negative impact on larval growth and development. Abamectin excreted 7 days after treatment resulted in few live larvae. Overall, moxidectin was the least toxic ML to the larvae assessed, and generally, the drench impacts were reduced as time since exposure increased.

Air-Fluidized Aggregates of Black Soldier fly Larvae

Black soldier fly larvae are a sustainable protein source and play a vital role in the emerging food-waste recycling industry. One of the challenges of raising larvae in dense aggregations is their rise in temperature during feeding, which, if not mitigated, can become lethal to the larvae. We propose applying air-fluidization to circumvent such overheating. However, the behavior of such a system involves complex air-larva interactions and is poorly understood. In this combined experimental and numerical study, we show that the larval activity changes the behavior of the ensemble when compared to passive particles such as dead larvae. Over a cycle of increasing and then decreasing airflow, the states (pressure and height) of the live larva aggregates are single-value functions of the flow speed. In contrast, dead larva aggregates exhibit hysteresis characteristic of traditional fluidized beds, becoming more porous during the ramp down of airflow. This history-dependence for passive particles is supported by simulations that couple agent-based dynamics and computational fluid dynamics. We show that the hysteresis in height and pressure of the aggregates decreases as the activity of simulated larvae increases. To test if air fluidization can increase larval food intake, we performed feeding trials in a fluidization chamber and visualized the food consumption via x-ray imaging. Although the food mixes more rapidly in faster airflow, the consumption rate decreases. Our findings suggest that providing moderate airflow to larval aggregations may alleviate overheating of larval aggregations and evenly distribute the food without reducing feeding rates.

Trichinosis in the Rostov oblast

In the Russian Federation, cases of infection with trichinosis in a population of people or animals are annually recorded. Trichinosis is intestinal and tissue helminthiasis of humans and a number of mammals, caused all over the world by nematodes. A person becomes infected with the parasite by eating meat containing live encapsulated Trichinella larvae. Mating takes place in the gastrointestinal tract, fertilized females are introduced into the intestinal mucosa with their anterior thinned ends. The clinical picture of trichinosis is accompanied by the development of myositis, degeneration of muscle fibers, and multiple edema. Deaths are not uncommon due to necrotic ulcerative lesions of the intestine and internal bleeding.

Results of Proficiency Testing for Trichinella in Poland, 2015-2019.

Trichinellosis is a zoonotic meat-borne disease caused by the nematodes of the genus Trichinella. Meat containing live Trichinella larvae is a source of infection. The examination of meat for Trichinella was introduced in 1869, but the digestion method for this did not appear in Poland until the late 1970s. Nowadays, the meat of all food animals susceptible to Trichinella spp. is examined in the frame of official post mortem control with the digestion method. The majority of laboratories in Poland meet the requirements of the ISO/IEC 17025 Standard (352 field laboratories). Laboratory personnel participate in quality control programs. This paper presents the results of proficiency tests (PTs) organized within 2015–2019 in Poland. Over this period, the laboratories examined 7580 samples (contamination levels: zero, one, three, and five larvae). Each laboratory was provided with a set of samples (one negative and three positive). Over 95% of the samples were considered correct in qualitative assessments, though the results of the quantitative evaluations were slightly lower, with 89% of samples being considered correct. Based on a sample evaluation, 88% of laboratories passed the PT comparison. A slight decrease was observed in the examination of samples spiked with five larvae, and great progress was achieved in samples containing three larvae. Low levels of sample contamination are sought after in laboratories but may make evaluations difficult. For this reason, we must consider increasing the number of larvae added to the samples in the next PTs.

Effects of live feed manipulation with algal‐derived antimicrobial metabolites on fish larvae microbiome assembly: A molecular‐based assessment

Opportunistic microorganisms acquired through rearing water or live feed ingestion are believed to underpin high mortality rates of fish larvae, constituting a production bottleneck for the aquaculture industry. We employed 16S rRNA gene sequencing to determine whether treatment of live feed (rotifers and Artemia) with algal-derived, antibacterial metabolites could alter bacterial community structure of gilthead seabream (Sparus aurata) larvae in a larviculture facility. Owing to a large degree of sample-to-sample variation, pronounced ‘legacy effects’ of live feed manipulation on the total fish larvae bacterial community could not be verified. Notwithstanding, the approach induced shifts in relative abundance of specific bacterial phylotypes in both the live feed and fish larvae. Some phylotypes representing opportunistic taxa such as Stenotrophomonas, Pseudomonas and Klebsiella displayed reduced abundances in the bacterial community of fish larvae fed metabolite-treated vs. control live feed. Conversely, potentially beneficial phylotypes in the Alphaproteobacteria clade were consistently—although not significantly—promoted in the treated larval samples. These outcomes encourage future microbiome manipulation attempts to improve fish larviculture. However, successful host colonization and competition with resident symbionts are primary barriers that need to be overcome if live feeds are to be used as effective delivery systems of beneficial bacteria to fish larvae.

Pathogenic fungi infection attributes of malarial vectors Anopheles maculipennis and Anopheles superpictus in central Iran

BackgroundDue to the effect of synthetic and commercial insecticides on non-target organisms and the resistance of mosquitoes, non-chemical and environmentally friendly methods have become prevalent in recent years. The present study was to isolate entomopathogenic fungi with toxic effects on mosquitoes in natural larval habitats.MethodsLarvae of mosquitoes were collected from Central, Qamsar, Niasar, and Barzok Districts in Kashan County, Central Iran by standard dipping method, from April to late December 2019. Dead larvae, live larvae showing signs of infection, and larvae and pupae with a white coating of fungal mycelium on the outer surface of their bodies were isolated from the rest of the larvae and sterilized with 10% sodium hypochlorite for 2 min, then washed twice with distilled water and transferred to potato-dextrose-agar (PDA) and water-agar (WA) media and incubated at 25 ± 2 °C for 3–4 days. Larvae and fungi were identified morphologically based on identification keys.ResultsA total of 9789 larvae were collected from urban and rural areas in Kashan County. Thirteen species were identified which were recognized to belong to three genera, including Anopheles (7.89%), Culiseta (17.42%) and Culex (74.69%). A total of 105 larvae, including Anopheles superpictus sensu lato (s.l), Anopheles maculipennis s.l., Culex deserticola, Culex perexiguus, and Culiseta longiareolata were found to be infected by Nattrassia mangiferae, Aspergillus niger, Aspergillus fumigatus, Trichoderma spp., and Penicillium spp. Of these, Penicillium spp. was the most abundant fungus isolated and identified from the larval habitats, while An. superpictus s.l. was the most infected mosquito species.ConclusionsBased on the observations and results obtained of the study, isolated fungi had the potential efficacy for pathogenicity on mosquito larvae. It is suggested that their effects on mosquito larvae should be investigated in the laboratory. The most important point, however, is the proper way of exploiting these biocontrol agents to maximize their effect on reducing the population of vector mosquito larvae without any negative effect on non-target organisms.

Live black soldier fly larvae (Hermetia illucens) provisioning is a promising environmental enrichment for pigs as indicated by feed- and enrichment-preference tests

Live black soldier fly larvae (BSFL) could function as environmental enrichment for pigs as they are edible, odorous, manipulable, and destructible, though the interest of pigs in live BSFL is unestablished. In this study, three trials were performed to assess this interest in order to verify the suitability of live BSFL as enrichment. Eight (Trial 1 & 2) and 16 (Trial 3) pairs of weaned pigs were included. In Trial 1, the relative motivation of pigs to consume live BSFL compared to corn, raisins and feed pellets was evaluated in no-choice and subsequent two-choice preference tests including all (combinations of) feed items. In Trial 2, the feed items in the no-choice and two-choice tests were provided in tubes that had to be rooted or pushed to access the feed items. In this trial BSFL, corn, feed pellets, and empty tubes were compared. In Trial 1 & 2 each day had two 15 min tests occurring six hours apart. In Trial 3 the long-term interest in live BSFL provided in the tubes for a 5-day period was compared to feed pellets provided in tubes, to jute sacks, and to rubber balls attached to chains. Tubes with live BSFL or pellets were refilled every morning. The relative interest was determined through intake of feed items and/or time spent interacting with the items, as measured by 1.5- or 1 min scan sampling. In Trial 3, the time spent on oral manipulation of pen mates was also scored through scan sampling. In all trials the interaction with and consumption of live BSFL was significantly higher compared to the other items, indicating a clear preference for live BSFL, and pigs remained engaged with BSFL as long as they were accessible. In Trial 3, interest in live BSFL decreased on day 5 compared to day 1, interest in jute sacks and feed pellets decreased on day 3 compared to day 1, and interest in rubber balls attached to chains was continuously low. Pigs also spent less time on oral manipulation of pen mates when having access to live BSFL, pellets, or jute sacks, compared to rubber balls attached to chains. Overall, pigs showed high and extended interest in live BSFL, confirming their suitability as edible environmental enrichment. Pigs were willing to work for access to live BSFL by rooting and pushing tubes, which can be employed when providing live BSFL as enrichment commercially.

Effect of Insect Live Larvae as Environmental Enrichment on Poultry Gut Health: Gut Mucin Composition, Microbiota and Local Immune Response Evaluation.

Simple SummaryHermetia illucens (HI) and Tenebrio molitor (TM) are considered innovative protein sources in animal nutrition. Recently, it has been discovered that low doses of insect meal can also act as gut prebiotics, providing an alternative to antibiotics. This is extremely relevant to the enhancement of gut health, specifically the absence, avoidance and prevention of gastrointestinal diseases in order to maintain animal welfare, health and performance. Insect meals have been proven to be effective in modulating gut morphometry, mucin composition and microbiota. However, no studies are available on the effects of live insect larvae. For these reasons, this study describes for the first time the effects of low doses of HI and TM live larvae as environmental enrichment on chicken mucin expression, local immune response and microbiota composition. The results herein obtained demonstrated that live insect larvae administered based on 5% of the expected daily feed intake did not impair mucin expression or local cytokine production. Furthermore, it seemed to produce a slight improvement of the caecal microbiota by enhancing a minor fraction of potentially beneficial taxa able to produce short chain fatty acids as an important source of energy for the enterocytes.The aim of this study was to evaluate the effect of Hermetia illucens (HI) and Tenebrio molitor (TM) live larvae as environmental enrichment on the mucin composition, local immune response and microbiota of broilers. A total of 180 four-day-old male broiler chickens (Ross 308) were randomly allotted to three dietary treatments (six replicates/treatment; ten animals/replicate): (i) control (C); (ii) C+HI; (iii) C+TM. Live larvae were distributed based on 5% of the expected daily feed intake. At slaughter (39 days of age), samples of duodenum, jejunum and ileum (twelve animals/diet) were submitted to mucin histochemical evaluation. Expression of MUC-2 and cytokines was evaluated by rt-qPCR in jejunum. Mucin staining intensity was not influenced by diet (p > 0.05); however, this varied depending on the intestinal segment (p < 0.001). No significant differences were recorded for IL-4, IL-6 TNF-α, MUC-2 and INF-γ gene expression in jejunum, while IL-2 was lower in the TM group compared to HI and C (p = 0.044). Caecal microbiota showed higher abundance of Clostridium, Saccharibacteria and Victivallaceae in the HI group, while Collinsella was higher in the TM group. The results suggested that live insect larvae did not impair mucin composition or local immune response, and can slightly improve caecal microbiota by enhancing a minor fraction of short chain fatty acid-producing taxa.

The Inhibitory Effect of Wood Creosote on the Movement of Anisakis Larvae: An Implication for the Treatment of Acute Anisakiasis

Introduction: Anisakiasis is a common disease in countries such as Japan, where raw or undercooked marine fish are frequently consumed. The disease is caused by accidental ingestion of a live larva of Anisakis in raw or undercooked marine fish. In typical cases, it causes abrupt gastrointestinal symptoms, such as epigastric pain, nausea, and vomiting. According to a published report, the disease was alleviated by oral ingestion of an over-the-counter drug containing wood creosote. Methods: We performed an in vitro experiment to elucidate whether wood creosote can inhibit the motor activity of Anisakis larvae, using infrared locomotion tracking and agarose gel penetration techniques. Results: Our results clearly demonstrate that wood creosote inhibits the motor activity of Anisakis larvae. The concentration of wood creosote used in our experiment is similar to that found in stomach juice when a usual oral dose is taken of the medicine containing wood creosote. Discussion/Conclusion: Our results suggest the potential usefulness of the medicine containing wood creosote in the treatment of acute Anisakis infection of the gastrointestinal tract.

Nano/microparticles in conjunction with microalgae extract as novel insecticides against Mealworm beetles, Tenebrio molitor

The intensive use of insecticides in global agricultural production has attracted much attention due to its many adverse effects on human health and the environment. In recent years, the utilization of nanotechnology has emerged as a tool to overcome these adverse effects. The aim of this work was to test different microparticles (zinc oxide (ZnO MPs) and silicon dioxide microparticles (SiO2 MPs)), and silver nanoparticles (Ag NPs) and to study their toxicity on a model organism, Tenebrio molitor. A comprehensive comparative study, which included more than a thousand mealworms divided into nine separate groups, was conducted. In addition to pure nano/microparticle solutions, the effect of particles mixed with the microalgae extract Chlamydomonas reinhardtii was also observed. Pure Ag NPs and SiO2 MPs resulted in larval mortality of more than 70% compared to that of pure ZnO MPs, in which the mortality rate was approximately 33%. A mixture of the algal extract with zinc oxide microparticles resulted in mortality that was double compared to that observed with pure ZnO MPs. In parallel, atomic absorption spectrometry (AAS) was used to determine the difference in the concentration of trace elements in the bodies of dead and live larvae.

Black soldier fly and yellow mealworm live larvae for broiler chickens: Effects on bird performance and health status.

The commercial broiler chicken strains are the result of successful selection programmes. Most of the problems related to welfare arise from the high growth rate and body weight. The use of environmental enrichments in intensive farming could have a positive effect on birds by increasing animal welfare. The aim of the study was to evaluate the effects of Hermetia illucens (HI) and Tenebrio molitor (TM) live larvae in the diets of broiler chickens on growth performance, carcass yield and health status. A total of 180 four‐day‐old male broiler chickens (Ross 308) were randomly allotted to 18 pens. Each pen was assigned to one of the three dietary treatments (6 replicates/treatment, 10 birds/replicate) as follows: (i) control diet (C): commercial feed (two feeding phases: starter [4–11 days] and grower [12–38 days]), (ii) HI: C + 5% of the expected daily feed intake (DFI) HI live larvae (calculated on dry matter [DM]) and (iii) TM: C + 5% of DFI TM live larvae (DM). At 39 days of age, birds were slaughtered. Growth performance parameters were overall not affected by dietary treatments, except for the grower phase feed conversion ratio (FCR) and the overall FCR being better in the TM broilers than the others (p < 0.01). No differences were observed for slaughtering performance and haematological and serum parameters, except for the spleen relative weight being higher (p < 0.01) in the birds administered with larvae when compared to the C group. Gut morphometric indexes and histopathological alterations were not influenced by insect larvae administration. In conclusion, the administration in limited quantities of HI and TM live larvae as environmental enrichment has no negative effects on broiler chicken growth performance and health status. A behavioural study could confirm that live insect larvae represent a novel natural environmental enrichment in broiler farming.

Control of Diaprepes abbreviatus (Coleoptera: Curculionidae) with Steinernema riobrave (Rhabditida: Steinernematidae) in Plasticulture Florida Strawberry

Diaprepes abbreviatus L. (Coleoptera: Curculionidae) is an occasional root pest of plasticulture strawberry in central Florida, USA. There are few chemical insecticide options for larval D. abbreviatus in strawberry. Therefore, we tested soil-applied aqueous Steinernema riobrave Cabanillas, Raulston and Poinar (Rhabditida: Steinernematidae), which is used for D. abbreviatus control in citrus. When S. riobrave was applied (100 infective juveniles per cm2) to the root zones of plants in a D. abbreviatus-affected area of a commercial strawberry field, less than 12% of plants were severely wilted or dead 17 d after treatment, whereas 23% of plants in control plots were wilted or dead. In research plots, peripheral plants and a central plant in each plot were infested with 4 late-instar D. abbreviatus and treated with 1 or 2 applications of S. riobrave (25 infective juveniles per cm2), 1 application of imidacloprid or water (control). Dead S. riobrave-infected D. abbreviatus larvae were recovered from plots to which S. riobrave was applied, but there was no effect of treatment on numbers of live larvae recovered 1, 2, and 3 wk post-application in the peripheral plants. At the end of the experiment, no live D. abbreviatus larvae were recovered from the central plants or the plants proximal to the central plants in plots treated once or twice with S. riobrave. Plant wilting and death due to larval D. abbreviatus root feeding was minimal (averages of 1–1.4 on a 1–5 rating scale) in plants proximal and distal to the central D. abbreviatus-infested plant. Treatment did not affect plant wilting and death rates in the proximal plants, but death of distal plants occurred only in control plots. Our results showed S. riobrave infected and killed late-instar D. abbreviatus in plasticulture Florida strawberry, and further research should be conducted to optimize S. riobrave applications and develop it into a management strategy for D. abbreviatus.

Sanitary condition of soil in the territory of Astrakhan state technical university and nearby territories of higher educational institutions

Objective. The authors of this article studied and analyzed the sanitary condition of the soil in the territory of Astrakhan State Technical University and the nearby territories of higher educational institutions. Materials and methods. The study was carried out in May June 2019 on the basis of the laboratory of the Department of Infectious Diseases and Epidemiology of Astrakhan State Medical University and the laboratory of the Department of Applied Biology and Microbiology of Astrakhan State Technical University. Thirty soil samples were taken from these territories. The studies of soil samples for parasitological indicators were performed according to the guidelines "Control Methods. Biological and Microbiological Factors. Methods of Sanitary and Parasitological Research", for microbiological indicators "Methods of Soil Microbiological Control". Results. The following results were obtained: the sanitary-parasitological condition of the soil in parks near higher educational institutions in Astrakhan remains very tense as evidenced by positive findings of geohelminthoses; when assessing the degree of epidemic hazard of soil, there were identified nematode eggs and adult worm Strongyloids, that corresponds to the indicators of moderately hazard soil; the presence of live strongylid larvae in the studied samples indicates contamination of the soil with feces of infested animals, and the presence of Ascaris eggs indicates contamination of the soil with sewage or feces of infested children walking and resting in these territories; the total microbial number on average gave indicators for evaluating the selected soil samples as a slightly polluted soil. Conclusions. The sanitary and parasitological state of soil in parks of Astrakhan higher educational institutions remains rather tense as evidenced by positive findings of geohelminthoses.

Effectiveness of sarolaner in the clinical management of furuncular myiasis in dogs naturally infested with Dermatobia hominis (Diptera: Cuterebridae)

BackgroundThe human botfly, Dermatobia hominis, is a common cause of furuncular myiasis in dogs in Latin America. Lesions can be single or multiple, each harboring an individual larva, presented as an erythematous nodule that causes pruritus and pain. Typical treatment consists of sedation for removal of larvae by surgical incision or manual pressure. Medications to kill the larva before its extraction can reduce inflammation and discomfort and provide a less traumatic larval removal. Isoxazolines are broad-spectrum ectoparasiticides with larvicidal activity previously reported in the treatment of screwworm myiasis in companion animals. The aim of this study was to evaluate the effectiveness of sarolaner as part of the clinical management of furuncular myiasis in dogs caused by D. hominis larvae.MethodsTen short-haired mixed breed dogs naturally infested with D. hominis were enrolled. Clinical diagnosis was achieved by observation of skin nodules and visualization of larval motility through the lesion orifice. Sarolaner was administered at manufacturer recommended dose for fleas and ticks. Lesions were reexamined 24 h post-treatment and assessed for viability of larvae. Larvae were removed by digital compression and identified as D. hominis.ResultsSeventy-five D. hominis larvae were retrieved from ten dogs. No live larvae were observed, demonstrating 100% larvicidal efficacy of sarolaner. Skin lesions were healed 30 days post-treatment and new lesions were not observed.ConclusionsSarolaner seems to be effective as larvicidal treatment for dogs with furuncular myiasis, reducing discomfort caused by the presence of the larva in the skin and facilitating its safe removal.Graphical abstract

Laser capture microdissection to study Bacillus cereus iron homeostasis gene expression during Galleria mellonella in vivo gut colonization

ABSTRACT Bacillus cereus is a Gram-positive opportunistic pathogen closely related to the entomopathogen, Bacillus thuringiensis, both of which are involved in intestinal infections. Iron is an essential micronutrient for full growth and virulence of pathogens during infection. However, little is known about iron homeostasis during gut infection. Therefore, we aimed to assess the expression of B. cereus genes related to bacterial iron homeostasis, virulence and oxidative stress. The hypothesis is that the expression of such genes would vary between early and later stage colonization in correlation to gut cell damage. To perform the study, a germ-free Galleria mellonella model was set up in order to adapt the use of Laser-capture microdissection (LCM), to select precise areas in the gut lumen from frozen whole larval cryo-sections. Analyses were performed from alive larvae and the expression of targeted genes was assessed byspecific pre-amplification of mRNA followed by quantitative PCR. Firstly, the results reinforce the reliability of LCM, despite a low amount of bacterial RNA recovered. Secondly, bacterial genes involved in iron homeostasis are expressed in the lumen at both 3 and 16 hours post force-feeding. Thirdly, iron gene expression is slightly modulated during gut infection, and lastly, the mRNA of G. mellonella encoding for ferritin and transferrin iron storage and transport are recovered too. Therefore, iron homeostasis should play a role in B. cereus gut colonization. Furthermore, we demonstrate for the first time the value of using LCM for specific in situ gene expression analysis of extracellular bacteria in a whole animal.

Feeding live Black Soldier Fly larvae (Hermetia illucens) to laying hens: effects on feed consumption, hen health, hen behavior, and egg quality

The use of insects in animal feed has the potential to reduce the demand for soybean production and reduce the deforestation and loss of natural resources. In particular, the black soldier fly (BSF, Hermetia illucens) larvae have received attention due to their ability to convert organic waste into high-value biomass. Several studies have investigated the effects of providing BSF larvae to both broilers and laying hens. However, knowledge gaps regarding hens’ voluntary intake of live larvae and the effects of larvae consumption on egg production still remain. Therefore, the aim of the present study was to determine the effects of the consumption of 4 different amounts of live BSF larvae on laying hen feed consumption, hen health and fearfulness, and egg production and quality. To this end, 40 Bovans White laying hens were housed individually and provided with 0, 10, 20% or ad libitum daily portions of live larvae from 18 to 30 wk of age. The larvae consumption and concentrate consumption, hen weight, egg production, and egg quality were monitored. Overall, differences were found between the hens given ad libitum access to larvae compared to the other treatments. Ad libitum hens, consumed 163 ± 41 g larvae/hen/day, consumed less concentrate (P = 0.03) and gained more weight (P = 0.0002) than all other treatments. They also had an overall higher consumption of protein, fat and energy (P < 0.03). There was no effect of larvae consumption on egg production, egg weight, shell thickness, shell breaking strength, or Haugh unit (P > 0.05). There was also no effect on hen behavior toward a novel object or in an open field test. This study is the first to provide different amounts of live BSF larvae, including an ad libitum portion to laying hens. The 20% diet could promote sustainability in the egg industry and be economically advantageous if BSF larvae can be bought in bulk for less than 40% of the cost of the concentrate.

Effectiveness of Chironomid Larvae in Compare to Other Fish Foods on Growth Parameters and Body Protein of Two Economically Important Fishes

With the increasing human population, the demand for healthy, nutritious but cheap food also increasing day by day. The product of aquaculture mainly fish is more efficient to improve global food security. Along with the seafood, the effort is going on for more production of freshwater fish. For that reason, proper growth and sufficient proximate principles in fish are essential with a low-cost but healthy fish diet. Trichogaster fasciata and, Heteropneustes fossilis were fed with fourth instar larvae of Chironomus striatipennis (F1), dry Tubifex (F2), and granular floating type aquarium fish food (F3) respectively to observe the nutritional effect of different fish meal. Fish fed with F1 showed effective food conversion ratio and specific growth rate in comparison to fish fed on F2 and F3 respectively. The average daily gain was 214.3 % and 47.61% respectively in two fish when fed with F1. Percent gain weight increased from 1.12 (7th day) to 15.03 (28th day) in T. fasciata and 1.497 (7th day) to 8.21 (28th day) in H. fossilis when fed on F1. The result also showed that the protein level was increased steadily in both fishes when fed with F1 in comparison to other foods. It may be concluded that live larvae of Chironomus striatipennis were more effective fish food than dry Tubifex and aquarium fish food. It is a natural organic fish food with a negligible wastage used for fish and keeps the culture medium clean and debris-free with an ecofriendly environment.

Near-infrared ratiometric fluorescence imaging of lysosomal polarity in live cells and in vivo

Lysosomal polarity changes have been reported to be able to reflect cell status in physiological and pathological processes, and may serve as a ubiquitous marker for cancer detection. Thus, to monitor polarity in lysosome is of great importance to distinguish abnormal cells in cell biology and oncologic pathology. Herein, a lysosome-targeted and near-infrared (NIR) emissive probe, named DCM-ML, was found to be highly sensitive toward polarity, with fluorescence intensity exhibiting a linearly ratiometric relationship (I655/I705) against polarity (Δf). The potential of DCM-ML for polarity detection has been successfully demonstrated in physiological and pathological processes in both cells and zebrafish. It was found that lysosomal polarity in cancer cells (HeLa, MCF-7 and HepG2) was lower than that in normal cells (LO2), and it would be gradually decreasing with the cell damage getting worse; while in contrast, lysosomal polarity increased gradually in autophagy process. Moreover, lysosomal polarity changes in zebrafish development were successfully monitored for the first time with the NIR ratiometric probe, which exhibited a gradually increasing trend during the development process. And polarity in live embryos and larvae was also found to be higher than that in dead ones. All the results demonstrate that DCM-ML has the potential application for cancer cell diagnosis, dead cell identification, and real-time monitoring of autophagy and zebrafish development processes by imaging of lysosomal polarity. The development of the probe should be helpful for studying lysosome-related physiological and pathological processes.

Species Identification of Wireworms (Agriotes spp.; Coleoptera: Elateridae) of Agricultural Importance in Europe: A New "Horizontal Identification Table".

Simple SummaryWireworms are soil-dwelling larvae that damage multiple arable crops. The most common wireworms found in European cultivated fields belong to the genus Agriotes. Large amounts of insecticides are applied on a prophylactic basis to control them; before any treatment can be applied, however, legislation imposes an assessment of whether pest population levels exceed a damage threshold above which a significant yield reduction is expected. Thresholds vary greatly among species, thus quick and reliable larval identification is needed. This will result in the implementation of the appropriate integrated pest management practices. Furthermore, research into non-chemical strategies involves carrying out tests with live wireworms identified to species. Wireworms were observed to identify live larvae rapidly on site to assess density and compared with species-specific thresholds before sowing, and for laboratory experiments to be performed. This work led to a “synoptic key” that reliably identifies most live larvae, while traditional keys consider only single characters step by step. The key considers several discriminating morphological characters in order of stability. Identification becomes reliable when at least two main discriminating characters are found and attributed to a single species.Wireworms are yellowish soil-dwelling larvae that damage a wide range of arable crops. The most common wireworms found in European cultivated fields (except for the Caucasus) belong to the genus Agriotes (Coleoptera: Elateridae). In several European countries, environment-impacting insecticides are applied on a prophylactic basis to control them. However, before any treatment can be applied, European legislation requires that an assessment is done when pest population levels exceed a damage threshold. The threshold substantially depends on wireworm species, thus quick reliable larval identification is needed to implement the appropriate integrated pest management practices. Furthermore, research into non-chemical strategies involves carrying out tests with live and identified wireworms. Thus, thousands of wireworms were observed in a bid to identify live larvae so that larval density could be assessed and compared with species-specific thresholds before sowing, and laboratory experiments were carried out. This work led to a horizontal identification table that allows for quick and accurate identification of live larvae. This key, unlike traditional dichotomous keys, simultaneously considers a set of multiple discriminating morphological characters in order of stability. The key can be reliably used by less experienced users and, once minimum familiarity is acquired, most larvae can be identified rapidly, with high precision.