Activation of Artemia cysts with the use of different substances

The aim of the study was to study the use of hydrogen peroxide and ascorbic acid of different concentrations as an activator for the incubation of artemia cysts. The work was carried out on cysts of artemia taken from several lakes of the Novosibirsk region (Western Siberia). During incubation, a standard method was used: the salinity of the water was 3%, the water temperature was 28□C, continuous aeration was carried out, constant illumination was 2000 lux. An activator was added to the water at different concentrations: ascorbic acid - 0.05, 0.1, 0.5, 1.0 g/l; hydrogen peroxide - 0.4; 0.6; 0.8; 1. The maximum hatching was observed at a concentration of 0.6 g/l of hydrogen peroxide, 82% for cysts from Lake Sakhalin and 68% - from Lake Barbashi. When using ascorbic acid, the maximum hatching of cysts was observed at a concentration of 0.1 g/l: Sakhalin - 81.4, Pokrovka - 75.3 and Barbashi - 66.7%. When using other concentrations of activators, the percentage of cysts hatching decreased. The obtained results indicate the need to select the activating substance and its concentration of activation of cysts for each lake individually.

Intra- and interpopulation variability of cysts and adults of Artemia (Branchiopoda: Anostraca) in Siberian populations (morphometry)

The size of Artemia cysts is an important indicator of their value as a food resource; to some extent, it allows to identify populations. The data on cysts of Artemia parthenogenetic populations (diameter, chorion thickness, and presence of spots on a shell), sampled in hyperhaline lakes of Western Siberia in different years, were analyzed, as well as the data on the morphometry of Artemia adults, reared from cysts at the same salinity. Significant intra- and interpopulation variability in the indicators was established. The absolute values of the cyst diameter were in the range of 210–330 µm, the mean values for the samples – 243.5–282.9 µm, the mean values for populations – 257.8–279.6 µm; the absolute values of the decapsulated cyst diameter were in the range of 196–294 µm, the mean values for the samples – 236.5–262.6 µm, the mean values for populations – 239.9–253.2 µm; the absolute values of the cyst chorion thickness were in the range of 3.3–16.9 µm, and the mean values for populations – 6.6–12.4 µm. In the main commercial fishing lakes, which account for about 70 % of the total catch of Artemia cysts in Russia, the cysts had similar mean population sizes: 262–268 µm. The absence of intrapopulation correlation between the cyst diameter and chorion thickness is concluded; so, they cannot serve as reliable indicators, identifying Siberian populations. Statistically significant correlation (r = −0.5) was established between salinity of a mother water body and Artemia embryo diameter. Cyst spotting, not exceeding 5 % in almost all the samples, reached 24 % in cysts of Kuchukskoye Lake. Analysis of morphometric indicators of Artemia adults, reared from cysts, showed as follows: the mean body length (9.27–11.63 mm), abdomen width (0.53–0.69 mm), and distance between eyes (1.36–1.52 mm) were closely correlated with salinity of a water body (r values were of −0.76; −0.62; and −0.67, respectively). Cluster analysis of a set of morphometric indicators of Artemia adults showed the unification of populations based on salinity.

Augmenting Nesidiocoris tenuis (Nesidiocoris) with a Factitious Diet of Artemia Cysts to Control Bemisia tabaci (Gennadius) on Tomato Plants under Greenhouse Conditions

Natural predators such as Nesidiocoris tenuis are known for their role in managing greenhouse pests. However, techniques in maximizing the biological control potential of N. tenuis under field conditions are still lacking. We evaluated under greenhouse conditions the prospects of Artemia cysts enhanced with high fructose corn syrup and honey, and delivered using hemp strings (hemp rope) as supplementary factitious dietary in augmenting the proliferation and spread of N. tenuis on tomato plants. Results showed that N. tenuis supplemented with hemp rope could establish, proliferate and disperse among tomato plants compared to the N. tenuis supplemented with banker plants. Even though N. tenuis proliferated exponentially on banker plants, their movement and relocation to tomato plants, as expected, were only congested on tomato plants near the banker plants. However, as the survey continued, they relocated to the rest of the tomato plants. Furthermore, the number of Bemisia tabaci eggs and nymphs, a serious greenhouse pest of tomato, was observed to be significantly reduced in hemp rope greenhouse compared to banker plants and the negative control (no pest control system) greenhouses. This study, therefore, establishes foundational data on the usage of Artemia cysts enhanced with isomerized sugar (high fructose corn syrup) and honey under greenhouse conditions as factitious supplementary dietary in supporting N. tenuis establishment and spread, traits that are essential towards development of whitefly Integrated Pest Management (IPM) system. enhanced with isomerized sugar (high fructose corn syrup) and honey.

The Effects of Artemia Cyst Harvesting on the Salt Lake Ecosystem

In Russia, the main stocks of Artemia cysts and cyst harvesting activities are concentrated in Western Siberia. About 1,100 tons of cysts are harvested annually, including 180 tons in the Kurgan Region and 140 tons from Medvezhye Lake (about 2 % of their world harvest). The purpose of this study was to determine the degree of influence of Artemia cyst harvesting on the ecosystem of a salt lake in a case study of Medvezhye Lake. The main trophic components of the ecosystem – phytoplankton, zooplankton, and zoobenthos – were analyzed. The salinity of the brine of Medvezhye Lake varied between 110 and 320 g/dm3 in different years. Phytoplankton in the lake function throughout the year. They are characterized by small cell sizes, low biomass (0.76±0.24 mg/L) and daily production (1.03±0.18 mgO2/L or 0.3±0.05 gC/m2), and high levels of A/B and P/B coefficients. Zooplankton and zoobenthos are represented mainly by Artemia. The biomass of Artemia shrimp reached 21.9±3.2 mg/L (219 kg/ha) on average during 1995-2018. During this period, the stock of cysts formed annually in the lake was 114.5±14.3 kg/ha; the harvest was 23.7±3.0 kg/ha (21 % of the stock). The main components of the ecosystem – phytoplankton – Artemia shrimp – Artemia cysts – were produced annually in the following proportions: 8390:2678:115 kg/ha·year (75:24:1 %). The removal of 23.7 kg/ha of the cysts (0.22 % of the production of all components) from the lake is negligible compared to the other components of the ecosystem. The residual density of cysts after harvesting, which is necessary for the reproduction of the Artemia population for the next season during the 1st generation, is 10 kg/ha. Averaged data indicate that the amount of Artemia cysts left in the ecosystem of Medvezhye Lake after cyst harvesting is 91 kg/ha, i.e. 9 times greater than the minimum required density. The results reported in the present study indicate that the current level of cyst harvesting cannot have any significant impact on the ecosystem of the hypersaline lake

Zernike phase-contrast full-field transmission X-ray nanotomography for 400 micrometre-sized samples

Full-field X-ray nanotomography based on a Fresnel zone plate offers a promising and intuitive approach to acquire high-quality phase-contrast images with a spatial resolution of tens of nanometres, and is applicable to both synchrotron radiation and laboratory sources. However, its small field of view (FOV) of tens of micrometres provides limited volume information, which primarily limits its application fields. This work proposes a method for expanding the FOV as the diameter of the objective zone plate, which provides a 400 µm FOV at below 500 nm resolution with Zernike phase contrast. General applications of large-volume nanotomography are demonstrated in integrated circuit microchips and Artemia cysts. This method can be useful for imaging/analyzing industrial and biological samples where bulk properties are important or the sample is difficult to section.

EXPERIMENTAL RESEARCH FOR TECHNOLOGICAL PREPARATION OF ARTEMIA (ARTEMIA) ARTIFICIAL CULTIVATION IN SALT LAKES

An integral part of the technological preparation of artificial cultivation of brine shrimp in saline water is a set of preliminary experimental work to assess the quality of cysts. It has been shown that during the winter period, activation of Artemia cysts occurs from the initial hatching values of 5-10 % to 72-99 %. The most optimal salinity range for hatching nauplii is a salinity of 20-30 g/l. With an increase in salinity above these indicators, hatching decreases. The size of hatching of Artemia depends on the salinity of a natural reservoir. In reservoirs with salinity of 50-80 g / l, higher hatching rates were obtained than with salinity of 150-160 g/l. Higher hatching rates are observed when using natural lake water for incubation. During incubation of cysts in a standard solution and fixed salinity and temperature conditions, the development rate of various stages of nauplii from the beginning of the opening of cysts (breaking stage) and pre-nauplius to active nauplii is shown. After 1.5–2 h after the mass appearance of pre-nauplii, they completely change into the nauplius stage.

QUALITY AND QUANTITY OF EPHIPIA MOINA MACROCOPA RESULTING FROM MATING USING TILAPIA FISH FECES SUSPENSION FEED

The needs of Artemia cysts in Indonesia currently reach ± ​​150 tons / year and all of them are from the imports, so it can become an obstacle in process of hatching fish and shrimp in the future. Increased Culture activities have an impact on increasing fisheries waste production, including fish feces. Fish feces have been proven to be used for the Culture of Moina macrocopa, but have not been tested for the production for ephipia M. macrocopa. This study aims to examine the use of fish aquaculture/feces as feed for the quality and quality of ephipia M. macrocopa. The treatment in this study was the concentration of suspension of tilapia feces 55 mg / L, 64 mg / L, and 73 mg / L and using rice bran suspension feed control 64 mg / L. The results of this study indicate that, the concentration of suspension of tilapia feces does not affect the production and hatching rate of ephipia M. macrocopa. M. macrocopa which was cultured with suspension of tilapia feces produced epiphia production and with a lower hatching rate compared to M. macrocopa with rice bran suspension feed.