Weight Of Larvae Research Articles

Effectiveness of particle size of selected plant materials as protectants of stored Clarias gariepinus against Dermestes maculatus infestation

The focus of this study was to determine the efficacy of the different particle sizes of the powder of three plant materials, African Nut-meg (Monodora myristica), Black pepper (Piper guineense) and dry bud of Cloves (Eugenia aromatica) in the control of Dermestes maculatus infestation on stored dried African mud catfish, Clarias gariepinus. Each plant material was pulverized, sieved into 0.5 mm and 0.4 mm particle-sizes, rubbed at 5 g of powder onto the body of 55 g dried fish and placed in Kilner jar in triplicates. The weight loss, adult / larvae emergence and adult mortality of treated fish were determined. The results showed that 0.4 mm particle size of the powder of P. guineense and E. aromatica prevented the infestation of D. maculatus as demonstrated by low fish weight loss, low level of adult / larvae emergence and high mean value of adult insect mortality. Higher number of larvae emergence and weight losses were recorded in the fish exposed to 0.5 mm of each plant powder and 0.4 mm of M. myristica. The study revealed that stored catfish could be treated with smooth particle sizes of Piper guineense and Eugenia aromatica, and can significantly serve as protectants of smoked C. gariepinus against Dermestes maculatus infestation.

Defense response of Fraxinus mandshurica seedlings to Hyphantria cunea larvae under Cd stress: A contradiction between attraction and resistance

Heavy metal pollution, as a common and serious environmental problem worldwide, has been regarded as an abiotic stimulus that can affect plant insect resistance and pest occurrence. This study evaluated the defense response of Fraxinus mandshurica seedlings to Hyphantria cunea larvae under Cd stress, with consideration given to chemical defense, physical defense, and elemental defense. Our results showed that the H. cunea larvae had a strong preference for Cd-treated F. mandshurica seedlings, but there was a significant reduction in body weight and survival rate in larvae that fed on leaves of Cd-treated seedlings. Under Cd treatment, the increase in attractant metabolites (e.g., styrene, dibutyl phthalate, and d-limonene) and the decrease in repellent metabolites (e.g., aromadendrene, heptadecane, and camphene) in leaf volatiles were responsible for the high attractant activity to H. cunea larvae. Based on leaf physicochemical properties, tissue structure, and phenolic acid content, an overall reduction in physical defense, chemical defense and their combination in F. mandshurica seedlings exposed to Cd stress was identified by Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) analysis. Elemental defense occurred in Cd-treated F. mandshurica seedlings, as evidenced by the high concentration of Cd in leaves and H. cunea larvae under Cd treatment. Taken together, these findings demonstrate that under Cd stress, elemental defense replaces the dominant role of basic defense in F. mandshurica seedlings and accounts for the enhanced ability to defend against H. cunea larvae.

Susceptibilities of Helicoverpa zea (Lepidoptera: Noctuidae) Populations From the Mississippi Delta to a Diamide Insecticide.

The corn earworm, Helicoverpa zea (Boddie), is a major pest of row crops in the Southern United States. Control of this insect is dependent on preventative insecticidal transgenic crops and synthetic insecticide applications when damaging populations are encountered in the field. Recently, the use of chemicals from the diamide class of insecticides, particularly chlorantraniliprole, has been used to control unacceptable populations. Due to the increased importance of this active ingredient for control of corn earworms, populations of this insect from the Mississippi Delta have been monitored for susceptibilities annually since 2016. Overall, 58 populations of H. zea were examined for their susceptibility to chlorantraniliprole through diet-incorporated bioassays from 2016 to 2021. Based on probit analysis, there was only a 4-fold difference between the highest and lowest LC50 estimates for all populations tested. Through weights of 2nd and 3rd instar larvae, there appears to be a substantial fitness cost associated with surviving caterpillars that fed on various concentrations of chlorantraniliprole in bioassays, which is not captured through the yes or no response of typical survival analysis. Overall, there was not a detectable trend of reduced susceptibility to chlorantraniliprole over the course of the six-year study.

The efficacy of Azotobacter chroococcum in altering maize plant-defense responses to armyworm at elevated CO2 concentration

Elevated atmospheric carbon dioxide (eCO2) concentrations can alter the carbon:nitrogen ratio and palatability of host plants for herbivorous insects, but rhizobacteria likely mitigate the alteration and influence physiological adaptation of insects. In this study, we conducted transcriptomic analysis of maize (Zea mays) response to Azotobacter chroococcum (AC) inoculation under eCO2 conditions in contrast to ambient CO2 (aCO2), and studied the effects of plant-defense change of maize under eCO2 on the oriental armyworm, Mythimna separata. Results showed that there were 16, 14, 16 and 135 differentially expressed genes that were associated with plant-defense response in maize leaves between aCO2-CK and aCO2-AC, eCO2-CK and eCO2-AC, aCO2-CK and eCO2-CK, aCO2-AC and eCO2-AC, respectively. Moreover, A. chroococcum inoculation and eCO2 influenced plant hormone signal transduction of maize. Interestingly, A. chroococcum inoculation significantly decreased the contents of JA (jasmonic acid) and JA-Ile (isoleucine conjugate of JA) in leaves, but eCO2 markedly increased contents of JA-Ile, JA and SA (salicylic acid). Compared to aCO2, eCO2 significantly decreased activity of protective enzyme (catalase), and increased activities of digestive (lipase and protease), protective (peroxidase) and detoxifying enzymes (carboxylesterase, Mixed-functional oxidase and glutathione s-transferase), prolonged developmental time, and decreased survival rate and body weight of larvae (P < 0.05). A. chroococcum inoculation significantly increased the activity of protective enzyme (catalase), and decreased the activities of detoxifying enzymes (carboxylesterase, glutathione s-transferase and mixed-functional oxidase), thus increased the growth rate and body weight of larvae in comparison with no-inoculation of A. chroococcum (P < 0.05). The indices of M. separata were significantly correlated with the foliar contents of JA, JA-Ile and SA (|r| = 0.44–0.85, P < 0.05), indicating that A. chroococcum inoculation altered the physiological adaptation of M. separata under eCO2 by disturbing defense substances in maize. Our results in understanding effects of A. chroococcum inoculation on maize resistance to herbivorous insects will be valuable for agricultural pest control in the future at eCO2 conditions.

Toxicity of Chemical Insecticides and Neem Oil on Cucurbit Fruit Fly Bactrocera cucurbitae

Background: The popular vegetable sweet gourd (Cucurbita moschata) is cultivated throughout Bangladesh. However, its yield is low owing to the severe infestation by fruit fly Bactrocera cucurbitae. This study investigated the toxicity of chemical insecticides and neem oil on fruit flies infesting sweet gourd. Methods: The repellency of adult fruit flies and larvae and the body weight and mortality of the larvae of the fruit fly were evaluated using three chemical insecticides- Karate 2.5 EC (cyhalothrin), Ripcord 10 EC (cypermethrin) and Shobicron 425 EC (profenofos Q+cypermethrin) and neem oil (azadirachtin). Result: The repellency rate of the fruit fly larvae varied from 20.0±0.0 to 86.7±6.7% and that of the adult fly from 13.3±6.7 to 73.3±6.7%; Shobicron 425 EC, at 2000 ppm, exhibited the best results in both the cases. The treatments negatively affected the weight of larvae compared to the control, where Shobicron 425 EC caused the lowest weight (7.8±0.2 mg). The insecticides at 24, 48 and 72 h after treatment demonstrated toxic effects on the larvae, where the LC50 values ranged from 742.5 (550.4-1060.5) to 2476.3 (2150.6-2954.7) ppm at 72 h after treatment. On the whole, Shobicron 425 EC demonstrated better efficacy than the other insecticides against fruit flies.

BmAbl1 Regulates Silk Protein Synthesis via Glutathione Metabolism in Bombyx mori.

Bombyx mori, domesticated from wild silkworms, is an economic insect that feeds on mulberry leaves and produces silk. In the current study, we demonstrated the contribution of BmAbl1 in silk protein synthesis. The inhibition and knockout of BmAbl1 can reduce the larva weight and CSW. The effect on CSW of BmAbl1 is not on the transcriptional level, but on the translational level. RNA-sequencing data suggested that amino acid synthesis and the metabolism process had a great difference between the BmAbl1- and Control strain, particularly glutathione metabolism. An abnormality in glutathione metabolism led to the reduction of free glycine and serine content, which are the main components of fibroin protein. Finally, fibroin protein synthesis has been reduced, including fibroin-heavy chain, fibroin-light chain, and p25 protein. This finding brought to light the role of BmAbl1 in the silk protein synthesis process.

Development of semi-artificial feed in the larva stage of the black soldier fly Hermetia illucens (Diptera: Stratiomyidae)

Abstract. Anasya AD, Sugiarto, Mahajoeno E. 2022. Development of semi-artificial feed in the larva stage of the black soldier fly Hermetia illucens (Diptera: Stratiomyidae). Nusantara Bioscience 14: 188-194. Alternative food sources in fish farming besides pelleted feed are generally used, but many have also used biotic materials, larvae of the black soldier fly (Hermetia illucens L.). Maggot stadia larvae have a high protein content of more than 19%, could be mass-produced, are low-priced, and has a fast growth time. Therefore, high levels of protein and nutrients in maggots can be increased through suitable semi-artificial formulations. The purpose of this study was to determine the nutritional value of the semi-artificial feed recipe given and to determine the effectiveness of the semi-artificial feed recipe in increasing the nutritional value and survival of larvae. Data analysis used qualitative analysis with descriptive analysis method and quantitative analysis by determining the amount of increased nutritional value of H. illucens. The research method was carried out in several stages, including (i) insect rearing obtained 2nd generation of tillers (F2); (ii) manufacture of semi-artificial feed recipes; (iii) calculation of insect survival; (iv) measurement of larval mass weight after treatment; (v) testing of nutritional content value includes water content, fat content and protein content of H. illucens after treatment. Results of the evaluation larval survival after treatment were effective enough 100%, larval instar life phase was between 28-32 days, while the highest increase in the nutritional value of larvae water content was 45.90%, fat content 7.25%, and protein content 45.95%, the average increase in mass weight of larvae was 12.50%.

Effects of Polystyrene Diet on the Growth and Development of Tenebrio molitor.

In recent years, the role of Tenebrio molitor in degrading polystyrene foam through its gut microbes has become the focus of research. However, little literature has reported the effect of feeding on polystyrene foam on the growth and development of Tenebrio molitor. In this study, we investigated the impacts of different polystyrene by evaluating the vital signs of Tenebrio molitor fed in the intestines and excrement fluids using RNA-Seq t.echnology and then verifying the transcriptome sequencing findings using qRT-PCR technology. The average weight of Tenebrio molitor larvae in the wheat bran group increased significantly. Tenebrio molitor larvae in the PS group, on the other hand, didn’t grow as much and had a much lower average weight than those in the wheat bran group. Compared to the bran group, the excrement of Tenebrio molitor fed only on polystyrene foam was flaky and coarse, increased nitrogen and phosphorus atomic concentration ratios by about 50%, decreased potassium atomic concentration ratios by 63%, with the enterocytes and circular muscle of Tenebrio molitor falling as well. Kyoto Encyclopedia of Genes and Genomes enrichment indicated that the differential genes were mainly related to metabolic pathways. There was an agreement between qRT-PCR and RNA-Seq analyses for the growth and development genes chitinase, heat shock protein 70, and cytochrome P450. Only feeding polystyrene foam shall lead to the growth and development retardation of Tenebrio molitor.

Omani Frankincense nanoemulsion formulation efficacy and its latent effects on biological aspects of the spiny bollworm Earias insulana (Boisd.).

Our research shed light on the perspective of formulation technology regarding its responsibility to provide phyto-insecticides that are worthy of research into potential novel applications. There has been an increase in interest in using nanoemulsion as a new formulation in a variety of sectors during the last several decades. Boswellia sacra essential oil (Fam: Burseraceae) from the resin of frankincense trees has been recently proposed as a promising ingredient in a new generation of botanical insecticides. Frankincense nanoemulsion was formulated in 5% ratios comprising frankincense oil, surfactants, and water. A frankincense nanoemulsion was prepared using a high-energy ultra-sonication process and characterized by dynamic light scattering transmission electron microscopy surface tension, viscosity, and zeta potential value. Gas chromatography/mass spectrometry (GC/MS) was used to identify the chemical profiles of frankincense essential oil. Furthermore, insecticidal effects against second instar larvae of the spiny bollworm, Earias insulana, as well as their latent effects on the larvae were studied. In the present study, the formulation was a good nanoemulsion. The surface tension was 53.69, the viscosity was 4.76 cPs, the zeta potential was-10 mV, and the size distribution was 41.30 nm. The polydispersity index (PDI) of the nanoemulsion was found to be 0.26, and the morphology of the frankincense nanoemulsion was visualized in a spherical shape. The main constituents identified in frankincense oil were α-pinene (15.52%); monolinolenin (12.92%); and geranylgeranyl acetate (9.99%). The results showed significant insecticidal activity against the larval stage and considerably decreased the pupation percentage with increasing the volume of the frankincense nanoemulsion. On the other hand, the latent effects of the frankincense nanoemulsion on E. insulana resulted in a higher prolongation of larval and pupal durations as well as a significant reduction in the weight of larvae and pupae of E. insulana. Additionally, frankincense nanoemulsion dramatically influenced the adult emergence percentage. It also caused a significantly lower hatchability percentage compared to the untreated control. The concentrations used and the types of mating combination have a significant effect on the fecundity of E. insulana. This novel frankincense nanoemulsion formulation could be used in strategies to control the spiny bollworm on cotton plants.

Biosynthesis optimization of silver nanoparticles (AgNPs) using Trichoderma longibranchiatum and biosafety assessment with silkworm (Bombyx mori)

Silver nanoparticles (AgNPs) have raised public concern due to their widespread application in the field of agriculture, medicine, and environment and their potential toxic effects on humans and the environments. In this study, biosynthesis of nanosilver particles mediated by Trichoderma longibranchiatum using orthogonal experimental design (OED) was optimized. Silkworm larvae were exposed via the mulberry leaves to AgNPs to evaluate their toxic effects. The results showed that 2 mmol/L silver nitrate and 55 °C of reaction temperature at pH 7.0 for 24 h were the optimum values for AgNPs biosynthesis with the synthesis amount and antifungal activity of AgNPs as the indices. The characterization of the biosynthesized AgNPs was conducted using electron microscopy, energy dispersive X-ray analysis (EDS), UV/visible spectrophotometry, Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The crystalline structured nanoparticles were spherical or polyhedral with a mean size ranging about 5–50 nm. FTIR showed that many functional group moieties (–OH, –CH 3 , –C–O, etc.) involved as a capping and reducing agent in AgNPs biosynthesis. After the larvae were fed with 50 mg/mL AgNPs, there were no obvious adverse effects on the growth of larvae and cocoon quality. Further supplement of AgNPs-B could promote the weight of larvae and the cocoon shell ratio. The data presented herein provided valuable information on a reliable eco-friendly, simple, low-cost biosynthesis of AgNPs and its biosafety evaluation which may contribute to its increased application in the future.

The effects of different stocking densities on nursery performance of Banana shrimp (Fenneropenaeus merguiensis) reared under biofloc condition

Abstract The effects of banana shrimp Fenneropenaeus merguiensis stocking density on water quality, growth performance, survival rate and body composition was assessed in a biofloc system with limited water exchange. The study was conducted for 32 days with an average larvae weight of 10 ± 0.85 mg in fiberglass tanks containing 120 L of water at four stocking densities. Five experimental treatments consisted of a control (density 1000 shrimps/ m3) with 50% daily water exchange and four biofloc treatments with limited water exchange (0.5% daily) at four stocking levels (1000 shrimps, T1; 2000 shrimps, T2, 3000 shrimps, T3 and 4000 shrimps, T4/ m3) were considered. According to the results, total ammonia nitrogen (0.99 mg/L) and nitrite levels showed higher amounts in the control compared with the other treatments (P&lt;0.05). Growth performance and survival rate (95.55%) in the biofloc treatment with a density of 1000 shrimps/ m3 were higher than the other treatments (P&lt;0.05). The proximate composition of shrimp body and biofloc produced in rearing tanks depended on the stocking density, so the shrimp body ash increased along with the enhancement of stocking density. The lowest amount of ash (31.53± 0.81%) and protein (26.38 ± 1.26) of bioflocs was observed in T1 treatment. The present study showed that stocking density affects the water quality, growth performance, survival rate and body composition of banana shrimp larvae in a biofloc system. More improved indices of water quality, growth performance and survival rate were observed with the least stocking density of 1000 shrimps/m3 in the limited water exchange system.

Starvation and cadmium affect energy reserves and oxidative stress in individuals of Spodoptera exigua

Different factors, such as starvation and metal exposure, may affect development and cause oxidative stress in insects. Some host plants may contain a high concentration of cadmium due to their hyperaccumulating property. The negative effects of metals and hunger may be manifested by low availability of energetic substrates. This study aimed to assess whether the insect population with a history of long metal exposure may better manage metal stress or/and starvation at different developmental stages, with the use of energetic substrates. Two strains of Spodoptera exigua model organism were tested: control strain and cadmium strain (treated continuously for over 200 generations with subtoxic amounts of cadmium). The effects of different factors, individually and in combination, on the tested strains were assessed, first by determining the body weight of larvae and pupae and then by estimating the concentration of biomolecules (proteins, carbohydrates, lipids, or glycogen) in the 4th and 5th larval stages and in pupae, and the total antioxidant capacity and lipid peroxidation level in the 4th larval stage. Compared to control strain, cadmium strain individuals exhibited changes in the concentration of soluble carbohydrates and protein. This was partly related to earlier 1-day starvation. In particular, changes in carbohydrate concentration seemed to be a sensitive biomarker of metal stress, independent of the age of individuals and period of starvation. However, the increase in the total antioxidant capacity and the concentration of lipid peroxidation products in the 4th larval stage under the effect of cadmium was dependent on strain origin.

Heterologous expression of cry1Ia12 insecticidal gene in cotton encodes resistance against pink bollworm, Pectinophora gossypiella (Lepidoptera: Gelechiidae); an alternate insecticidal gene for insect pest management.

Cotton is continuously exposed to sucking and chewing insect pest pressure since emergence to harvesting. Pink bollworm (Pectinophora gossypiella) has become major chewing insect pest to reduce the cotton yield and results in bad lint quality even in transgenic crops. The efficiency of insecticidal genes has been compromised due to extensive utilization of transgenic crops. The present study was conducted to evaluate the efficacy of an alternate cry1Ia12 insecticidal gene against pink bollworm (PBW) in cotton. Agrobacterium tumefaciens strain LBA4404 harboring pCAMBIA2300 expression vector containing cry1Ia12 gene under the control of 35S CaMV was used to transform a local cotton cultivar GS-01. The various molecular analyses revealed the transgene integration and expression in primary transformants. Among five selected transgenic plants, tcL-08 showed maximum (16.06-fold) mRNA expression of cry1Ia12 gene whereas tcL-03 showed minimum (2.33-fold) expression. Feeding bioassays of 2nd and 3rd instar pink bollworm (PBW) larvae on immature cotton bolls, flowers and cotton squares revealed up to 33.33% mortality on tcL-08 while lowest mortality (13.33%) was observed in tcL-03 and tcL-15. Furthermore, the average weight and size of survived larvae fed on transgenic plants was significantly lesser than the average weight of larvae survived on non-transgenic plants. The present study suggests the cry1Ia12 gene as an alternate insecticidal gene for the resistance management of cotton bollworms, especially PBW.

Carob (Ceratonia siliqua) as Functional Feed Is Beneficial in Yellow Mealworm (Tenebrio molitor) Rearing: Evidence from Growth, Antioxidant Status and Cellular Responses.

In terms of sustainability and circular economy, agricultural by-products may be efficiently reused in insects’ rearing for high-quality protein sources in human diet and animal feeds. The present study aimed to explore whether the utilization of carob pods as feeding substrate may beneficially affect Tenebrio molitor’s growth, nutritional value, antioxidant status and cellular responses. Increasing levels of milled whole carob pods (0, 25, 50, 75, 100%) were used as alternative wheat bran (control) substrates for yellow mealworm rearing, while growth performance, proximate composition, total phenolic content, antioxidant enzyme activity and the expression of stress- and apoptotic-related proteins were evaluated in larvae. The results showed that carob pods’ content up to 75% did not significantly differentiate larvae weight, development time and total dry matter. Larvae total phenolic content and antioxidant activity exhibited a significant increase at 75% content. Although the antioxidant enzymes’ activity decreased at both 25 and 50% levels, higher carob content levels (75 and 100%) resulted in no significant changes compared to the control. Carob pods led to decreased apoptotic indicators and the low expression of most stress-related proteins compared to the control. The present findings demonstrate that carob pods and their antioxidant properties exert beneficial effects on T. molitor’s rearing and nutritional status, although 100% carob content may impact adversely the larvae due to the high amounts of carob tannins.

A method for rearing and assessing the health of the sugarcane pest Dermolepida albohirtum (Coleoptera: Scarabaeidae)

AbstractRearing insects in controlled conditions is a prerequisite to supply high‐quality specimens for bioassays. However, while artificial diets and standardized rearing methods have been developed for many phytophagous insects, especially Lepidoptera, there are limited published diets for root‐feeding Coleoptera which are commonly fed either grass roots or pieces of vegetables as a simple alternative to artificial diets during bioassays. These feeding options, while convenient, can be considered suboptimal as they do not maximise the insects' development and health. Additionally, it is also important to develop standardised screening methods designed to test sublethal effects of control agents which may have repellent, antifeedant, antimetabolic and/or delayed mortality effects. The greyback canegrub (Dermolepida albohirtum, Waterhouse) is the most damaging native pest of Australian sugarcane, but no rearing method or artificial diet has ever been developed for this species. Our objectives were to improve bioassay methodology for D. albohirtum by describing and developing standard rearing and health assessment protocols. We describe a successful rearing method to raise healthy D. albohirtum larvae with a total of 48.8% of first instars successfully moulting to the second instar. We also tested a modified artificial diet which increased the weight, size and food uptake of larvae compared to traditional methods (i.e., pieces of carrots). For example, the average weight increase of larvae fed with the modified diet was 3.4 times higher than for carrot‐fed larvae while modified diet‐fed larvae were 2.1 times wider than if they were fed with carrots. Finally, we developed a method to measure larval activity which can be used to identify sublethal effects of control agents such as effects on activity level. Our methods may also be applied to improve bioassay methodology for other root‐feeding Coleoptera.

Extremely Low-Frequency Electromagnetic Field Impairs the Development of Honeybee (Apis cerana).

Simple SummaryThe ELF-EMF pollution generated by the increase in electrically powered devices and power lines, accompanied by economic development, has a widespread effect on surrounding organisms. Honeybees are one of the most important pollinators. The decline in the honeybee population caused by a variety factors, including EMFs, has attracted attention worldwide. It was already known that ELF-EMFs could impair the ability of learning and cognition, causing foraging bees to lose their ability to find their way home. The pollination ability of foraging bees is derived from the rearing quantity of larvae and continuous eclosion of new adult bees in the colony. However, the effect of ELF-EMFs on honeybee larvae is not clear. The aims and objectives of this study were therefore to investigate it. The results showed that ELF-EMF exposure decreases honeybee survival rate and body weight and extends the duration of development time. Transcriptome sequencing showed that ELF-EMF exposure decreases the biological process of nutrient and energy metabolism, impedes the degradation of larvae tissues and the rebuilding of pupae tissues in the metamorphosis process, and seriously interferes with the growth and development of honeybee larvae. This provides an experimental basis and new perspective for protecting honeybee populations from ELF-EMF pollution.Increasing ELF-EMF pollution in the surrounding environment could impair the cognition and learning ability of honeybees, posing a threat to the honeybee population and its pollination ability. In a social honeybee colony, the numbers of adult bees rely on the successful large-scale rearing of larvae and continuous eclosion of new adult bees. However, no studies exist on the influence of ELF-EMFs on honeybee larvae. Therefore, we investigated the survival rate, body weight, and developmental duration of first instar larvae continuously subjected to ELF-EMF exposure. Moreover, the transcriptome of fifth instar larvae were sequenced for analyzing the difference in expressed genes. The results showed that ELF-EMF exposure decreases the survival rate and body weight of both white-eye pupae and newly emerged adults, extends the duration of development time and seriously interferes with the process of metamorphosis and pupation. The transcriptome sequencing showed that ELF-EMF exposure decreases the nutrient and energy metabolism and impedes the degradation of larvae tissues and rebuilding of pupae tissues in the metamorphosis process. The results provide an experimental basis and a new perspective for the protection of honeybee populations from ELF-EMF pollution.

Optimization of the production of black soldier flies Hermetia Illucens by controlling biological parameters in Côte d'Ivoire

This study was conducted at the ENS vivarium located at the UFHB of Cocody in the city of Abidjan in the south of Ivory Coast, with a temperature of about 28° C and a humidity of about 70%. It aimed to study some biological parameters of the black soldier fly Hermetia illucens. For achieve this goal, it was a question of studying the different stages of development of the black soldier fly and also studying the evolution of its growth parameters. The flies were captured, kept in an aviary and observed from the fly stage to the end of the pupal stage (emergence of the first flies). Data on the duration of the different stages of development and the evolution of larval growth parameters (average weight, length, width, Fulton index, length/width ratio, survival and mortality rate of larvae) have been taken. This study revealed that the life cycle of Hermetia illucens is between 31 and 43 days, with an incubation time of eggs that lasts 2 days, a larval phase of 14 days, a pupation of 10 days and a duration of adult life of 8 days on average. In addition, this study reports a low mortality rate of larvae (3.45%), larvae much longer (19.46 mm), wider (6 mm) and plumper.

Bioconversion Potential of Agro-Industrial Byproducts by Tenebrio molitor-Long-Term Results.

Simple SummaryDue to the forecasted overpopulation of the globe in the coming decades, the possibility of using nutrients (proteins, fats, vitamins) from sustainable sources such as insects has been discussed extensively. Although insects have been widely consumed in Asian and Latin American countries since ancient times, they are a novel food on the European continent. The first insect-based product that was allowed on the European market in early 2021 was powdered yellow mealworm (Tenebrio molitor), and later, in December 2021, frozen and dried mealworms. Agricultural byproducts are a valuable source of nutrients that can serve as a feed for insect rearing, contributing to better bioconversion of nutrients and promoting insects as a safe protein source. The present study has evaluated the bioconversion potential of yellow mealworm larvae grown on 13 diets composed of different agro-industrial byproducts. During the experiment, the larval weight gain and feed consumption were evaluated to calculate the feed conversion ratio and efficiency of ingested feed, as well as the larval development time. The results show that the best mixes for insect rearing were those that contained rapeseed meal and chicken feed, as they significantly improved the feed conversion ratio and efficiency of ingested larvae feed.The aim of this study was to compare the growth performance, feed conversion ratio (FCR), and efficiency of ingested feed (ECI) by larvae of the Tenebrio molitor beetle. The growth and development potential of the yellow mealworm was evaluated by using chicken feed (CF), rapeseed meal (RM), wheat bran (WB), and willowleaf sunflower (WS) to obtain inexpensive and various sources of feed. The results showed that the fastest growth with shorter larval development time (74.7 days) was found for insects fed a WB 100 diet. Regarding the final fresh weight of larvae, the highest values were found for larvae grown on WB diets. However, the lowest FCR (1.53 to 1.59) was found for larvae fed RM diets mixed with CF and on the control diet (CF 100). In most cases, it was found that byproduct diets mixed with CF improve the ECI of mealworms, thus contributing to an efficient bioconversion of byproducts into edible sources of nutrients. Thus, except for pure WS as a feed, these byproducts can be used to grow yellow mealworm larvae and may be added to the versatile list of substrates and feed used by small- and large-scale insect producers.

Influence of Water Salinity on the Growth and Survivability of Asp Larvae Leuciscus aspius (Linnaeus, 1758) under Controlled Conditions.

Simple SummarySerious biological imbalances are often caused by poorly thought-out and destructive human activity, but also by progressive climate change. Each of these factors has an enormous impact on the life of terrestrial and aquatic organisms, including fish. As a result of the anthropogenically altered river environment, individual species must migrate from typically fresh to brackish waters that form in river mouths in order to conduct natural life processes such as spawning, as well as in search of food. An excessively high salinity level can be fatal to freshwater finfish, but low salinity can positively affect the growth and survival of larvae, fry and adult fish.The effect of water with a salinity 3, 5, 7, 9 and 11 ppt on the growth and survivability of asp Leuciscus aspius (L.) larvae was investigated. A control sample consisted of asp larvae reared up in freshwater (0 ppt). Larvae were fed for 21 days with nauplii of the brine shrimp Artemia salina. Water salinity was observed to have a considerable effect on the growth and survivability of asp larvae. In addition, saline water extended the life span of Artemia salina nauplii, which resulted in their prolonged availability to asp larvae. Asp larvae showed low tolerance to the salinity of water, reaching 9–11 ppt. Depending on the degree of salinity, the mean final weight of larvae varied from 122.6 to 139.4 mg, at body lengths from 23.8 to 25.6 mm, respectively. The best body length increments were recorded among asp larvae maintained in water with a salinity of 3 ppt. Depending on the level of water salinity, the final survivability of asp larvae ranged from 16.9 to 94.5%. The highest and increasing mortality was demonstrated among the larvae reared in water of the salinity equal to 11 ppt. It is not recommended to rear asp larvae in water with a salinity above 7 ppt due to the low survivability and large differences in the body size of the larvae that managed to survive.

Modulating the Fatty Acid Profiles of Hermetia illucens Larvae Fats by Dietary Enrichment with Different Oilseeds: A Sustainable Way for Future Use in Feed and Food.

Simple SummaryMost of the vegetable oils represent a suitable source of unsaturated fatty acids and bioactive compounds, which can be the key to solving different nutritional limitations. The fatty acid profile of Hermetia illucens larvae fats can be modulated through dietary enrichment as a result of adding vegetable oils to the rearing substrate. Therefore, the present research analyzes the effects of a 10% addition of vegetable oils from five dietary fat sources in larvae diets on the productive performances and fatty acid profiles of H. illucens. Oil inclusion in the larval diet improved (p < 0.05) the weight of larvae, prepupae, pupae, and imago without influencing (p > 0.05) the egg clutch weight and the number of eggs in the clutch. In addition, the larvae FA profile was enhanced in unsaturated fatty acids (p < 0.001), especially in long-chain polyunsaturated fatty acids from the omega-3 series, when the linseed oil, hempseed oil, and rapeseed oil were used in larvae diets.Edible insects such as the black soldier fly Hermetia illucens L. represent a potential and sustainable source of nutrients for food and feed due to their valuable nutritional composition, which can be modulated through dietary enrichment. The high content of saturated fatty acid (FA) of Hermetia illucens larvae fats can be modulated through dietary enrichment as a result of adding vegetable oils in the rearing substrate. Therefore, the present research aims to highlight the effects of a 10% addition of vegetable oils from five dietary fat sources (linseed oil, soybean oil, sunflower oil, rapeseed oil, and hempseed oil) on the growth, development, reproductive performance, and the fat and fatty acids profile of H. illucens. Oil inclusion in the larval diet improved (p < 0.05) the weight of larvae, prepupae, pupae, and imago without influencing (p > 0.05) the egg clutch weight and the number of eggs in the clutch. In addition, the larvae fatty acid profile was different (p < 0.001) according to the oil type, because the unsaturated FAs (UFA) increased from 11.23 to 48.74% of FAME, as well as according to the larvae age, because the saturated FAs decreased from 85.86 to 49.56% of FAME. Linseed oil inclusion led to the improvement of the FA profile at 10 days age of larvae, followed by hempseed and rapeseed oil. These three dietary treatments recorded the highest concentrations in UFA (29.94–48.74% of FAME), especially in polyunsaturated FA (18.91–37.22% of FAME) from the omega-3 series (3.19–15.55% of FAME) and the appropriate n–6/n–3 ratio. As a result, the degree of the lipid polyunsaturation index increased (17.76–41.44) and the value of the atherogenic (3.22–1.22) and thrombogenic (1.43–0.48) indices decreased. Based on the obtained results, it can be concluded that enriching the larval diet with these oils rich in UFA can modulate the larvae FA profile, making them suitable sources of quality fats for feed and indirectly for food.