Mass Production Of Larvae Research Articles

Future Proteins: Sustainable Diets for Tenebrio molitor Rearing Composed of Food By-Products.

Since the human population is continuously growing, sufficient food with low environmental impact is required. Especially, the challenge of providing proteins will deepen and insects can contribute to a more sustainable and efficient source of protein for human consumption. Tenebrio molitor larvae are highly nutritious and rearing mealworms is more environmentally friendly compared to the production of traditional livestock meat. To use T. molitor as a more sustainable alternative to conventional proteins, it is essential to apply diets from a local and sustainable source. Therefore, the objective of this study was to find local by-products or leftovers which can be used in mass production of larvae as a main substrate. Feeding trials investigating twenty-nine different substrates were conducted to evaluate larval growth performance and adult reproduction by determining development times, survival rates, biomass, and fecundity. Several suitable by-products were identified that can be used in high quantities as single component diet for T. molitor rearing, revealing a high survival rate, short development time, high mean total biomass, and successful breeding. The most successful substrate-malt residual pellets-was found to be an alternative to the most used substrate, wheat bran. Furthermore, corn germ meal, sweet chestnuts, bread remains, soybeans, sweet potatoes, and wheat germs have been discovered to be suitable diets for T. molitor. Moreover, the findings of this study contribute towards using several substrates as supplements.

Hermetia illucens (L.) (Diptera: Stratiomyidae) Odorant Binding Proteins and Their Interactions with Selected Volatile Organic Compounds: An In Silico Approach.

Simple SummaryThe black soldier fly (BSF) is a saprophagous insect that is an efficient bioconverter of organic waste because of its extreme voracity and fast larval development. Specific chemical molecules from decaying organic substances can influence BSF behaviour; in particular, several are likely attractants for BSF and are able to induce female oviposition and larval feeding. In insects, the perception of volatile organic compounds (VOCs) is based on a wide arsenal of chemoreception proteins. As a first step in understanding this process, an assessment of chemoreception genes belonging to the larval and adult stages of Hermetia illucens was conducted together with candidate VOCs that potentially regulate adult females searching for oviposition sites and phagostimulants for their larval progeny. The genes encoding several odorant binding proteins (OBPs) of interest were identified and three-dimensional models of these proteins were created, allowing a preliminary investigation of how different VOCs may interact with their binding sites. The present study provides a road map for further analysis and correlation among insect olfactory proteins and VOCs indicative of organic decomposition, starting from a computational approach to establish a reliable correlation between them.The black soldier fly (BSF), Hermetia illucens (Diptera: Stratiomyidae), has considerable global interest due to its outstanding capacity in bioconverting organic waste to insect biomass, which can be used for livestock, poultry, and aquaculture feed. Mass production of this insect in colonies requires the development of methods concentrating oviposition in specific collection devices, while the mass production of larvae and disposing of waste may require substrates that are more palatable and more attractive to the insects. In insects, chemoreception plays an essential role throughout their life cycle, responding to an array of chemical, biological and environmental signals to locate and select food, mates, oviposition sites and avoid predators. To interpret these signals, insects use an arsenal of molecular components, including small proteins called odorant binding proteins (OBPs). Next generation sequencing was used to identify genes involved in chemoreception during the larval and adult stage of BSF, with particular attention to OBPs. The analysis of the de novo adult and larval transcriptome led to the identification of 27 and 31 OBPs for adults and larvae, respectively. Among these OBPs, 15 were common in larval and adult transcriptomes and the tertiary structures of 8 selected OBPs were modelled. In silico docking of ligands confirms the potential interaction with VOCs of interest. Starting from the information about the growth performance of H. illucens on different organic substrates from the agri-food sector, the present work demonstrates a possible correlation between a pool of selected VOCs, emitted by those substrates that are attractive for H. illucens females when searching for oviposition sites, as well as phagostimulants for larvae. The binding affinities between OBPs and selected ligands calculated by in silico modelling may indicate a correlation among OBPs, VOCs and behavioural preferences that will be the basis for further analysis.

Larval development and metamorphosis in the sea urchin Loxechinus albus (Echinodermata: Echinoidea): Effects of diet type and feeding frequency

Techniques presently used in the mass production of larvae and juveniles of the sea urchin Loxechinus albus require optimization of methods related to their feeding. For this reason, the present research evaluated the effects of the type of diet and the frequency of feeding on morphological development and larval survival, as well as on the success of larval metamorphosis. The effect of the diet type was assessed in an experiment with three microalgal diets ( Chaetoceros calcitrans = C, C. calcitrans and Isochrysis galbana = CI and C. calcitrans, I. galbana, and Tetraselmis suecica = CIT). The effect of feeding frequency was assessed in a second experiment with three feeding regimes (daily feeding at normal ration—DN, feeding every second day at normal ration—SN, and feeding every second day at double ration—SD). Total larval growth and the growth of larval structures were affected by the type of food and by the feeding frequency. Larvae fed diets C and CI showed no significant difference in survival of competent larvae (mean ± SD: 48.8 ± 16.9 and 58.3 ± 14.4%) and in percent metamorphosis (59.3 ± 13.5 and 56.7 ± 10.3%). The size of the postmetamorphic sea urchins was significantly greater for the CI treatment (419.6 ± 35.4 μm) than for the C treatment (403.3 ± 31.6 μm). Larvae fed with CIT diet did not reach competence. Larvae fed at the DN regime reached competence in significantly greater numbers (46.0 ± 3.7%) than those fed with the SN regime (29.8 ± 5.5%) or the SD regime (31.4 ± 7.5%). There was no significant difference in the numbers of larvae achieving metamorphosis between regimes DN (49.3 ± 8.6%) and SD (57.3 ± 9.4%), but both means were greater than that of the SN regime (2.7 ± 2.1%). The postmetamorphic urchins from regime DN reached the largest size (413.9 ± 39.5 μm). The results suggest that daily larval feeding which includes a mixed diet of larger algal cells, including C. calcitrans but excluding T. suecica, may produce better results for large-scale production of competent larvae and juveniles of L. albus.

Cultivation of the erizo: an evaluation of eggs and postmetamorphic juveniles size selection

Evidence in the course of experiments under controlled conditions proved that the egg and juvenile characteristics of the edible Chilean sea urchin, ‘erizo’ (Loxechinus albus) influence the cultivation efficiency. Mortalities among larvae originating from eggs with a diameter 100 Μm. On the other hand, the initial size of the egg did not produce any variation in the percentage of larvae which metamorphosed. The initial size of the late metamorphosing juveniles modified early growth. A direct relationship was established between the size of the juveniles and the growth rate. In conclusion, biological aspects are determinant factors in any consideration of options available for the mass production of larvae and juveniles of this sea urchin.