Period Of Sexual Maturation Research Articles

INTERSEXUALIDADE EM CADELA DA RAÇA PITBULL TERRIER - RELATO DE CASO

Intersexuality is one of the disorders of sexual development that affect animals of various species. The changes occur during sexual differentiation and embryonic development of the reproductive system. Hermaphroditism is an anomaly in which the animal presents ambiguous sexual characteristics. This is an uncommon alteration in dogs, and may present varying degrees of ambiguity of the internal and external genitalia. This paper reports a case of a Pit Bull dog that presented characteristics of hermaphroditism during the period of sexual maturity, which was confirmed through histopathological evaluation as a case of male pseudohermaphroditism and describes the surgical procedure, characterized as the treatment of choice.

Using species population structure to assist in management and decision-making in the fight against invasive species: The case of the Atlantic blue crab Callinectes sapidus

The blue crab Callinectes sapidus Rathbun, 1896 is an invasive species in the Mediterranean, with a remarkable ability to adapt to various habitats, and thereby having significant impacts on biodiversity and artisanal fishing activities. Currently, fishing is a measure being considered to control blue crab populations in invaded sites. However, it is necessary to understand the temporal structure of blue crab populations (e.g., growth, reproduction, sexual maturity) to determine specific periods when control measures need to be implemented. Considering the species' ability to adapt to various habitats, it is crucial to evaluate how temperature and salinity influence population structure. In this study, we present fishers-dependent monitoring on the temporal population structure of blue crabs in two lagoons in Corsica (France) over 12 months. Through this approach, we provide new information that can assist in decision-making for the implementation of control measures. Even though these two lagoons are geographically close, blue crab populations showed differences, particularly in terms of sexual maturity. Specimens from Biguglia mature later (males: 16.16 cm; females: 16.79 cm) than those in the Palo Lagoon (males: 14.38 cm; females: 13.86 cm). Seasonal size distribution also showed differences between the lagoons and within the same lagoon between males and females. Temperature and salinity had a significant effect on the monthly relationship between carapace width and wet weight (referred to here as growth rate) for males and females and between the lagoons. In the Biguglia Lagoon, the higher the temperature, the greater the growth rate over a wide salinity window (16–30 psu); for females, the environmental window was restricted (temperature: 20–30°C; salinities > 16 psu). The dynamics differed in the Palo Lagoon, with a more restricted high growth rate window for males, and females showed a much wider window, with high growth rates over the entire temperature and salinity range. By employing blue crab’s populations monitoring along with environmental parameters, we were able to determine how the environment influenced the blue crab’s population structure, thus identifying periods conducive to species control. The most effective strategy would undoubtedly be to eliminate females before their period of sexual maturity and copulation ensue. In our case, this would involve intensive control in summer for Biguglia and in spring for Palo. These recommendations have been translated into operations to be implemented as part of the "Territorial Plan for Combating the Blue Crab (Callinectes sapidus) in Corsica (2024–2027)".

Investigation on the Biology of Helicoverpa armigera (Hubner) on Chickpea under Laboratory Condition

The Helicoverpa armigera (Hubner) is a polyphagous pest that is found throughout the world. Due to its damaging nature, it causes quantitative as well as qualitative loss and finally overalleconomic loss in agricultural crop production. So, the present investigation was done by rearing of H. armigera on chickpeas under laboratory conditions. The study revealed that this pest has four distinct stages i.e., egg, larva, pupa, and adult for completing its life cycle. The total life cycle of males and females were completed in 49-50 days and 52.30-53.00 days, respectively. The wholelife period was divided asthe incubation period takes 4-5 days, larval stage was completed in 20.00-20.50 days by passing through six instars under laboratory conditions at a temperature of 27±10C with 70±5 % relative humidity in 12 hours of light. The last larval instar did not molt and it contracted into a grub-like pre-pupal stage which lasted for 2-3 days and a pupal period of 13-14 days. The adult period of male and female insects was completed in 8.50-9.00 and 12.00-12.50 days, respectively. The female moths had a pre-oviposition period of 3-4 days that included a sexual maturity period. The oviposition and post-oviposition periodsrecorded were 5-6 days and 2 days, respectively. A single female produced on average 992.50-1085 eggs throughout her entire life span. The average hatching percentage of eggs recorded on 63.00-67.50 percent.

Akkermansia muciniphila Promotes Bone Development and Improves Eggshell Quality during the Sexual Maturity Period of Laying Hens by Increasing Osteogenesis

Adequate bone development is imperative for maintaining the health and productivity of laying hens. Probiotics play a pivotal role in promoting bone formation and preventing osteoporosis. This study aimed to explore the effect of Akkermansia muciniphila (Akk) on the bone development and eggshell quality of laying hens during the rearing period. A total of 300 1-day-old Jingfen NO. 6 commercial pullets were categorized into two groups, one of which was fed a conventional diet for 20 weeks (Control group), the other group was fed a conventional diet with lyophilized Akk powder for 20 weeks (Akk group). During the first two weeks, pullets in the Akk group received live Akk inoculation, while birds in the Control group received normal saline administration. Micro-computed tomography analysis was employed to evaluate three bone microarchitectures: cortical bone (Cb), trabecular bone (Tb), and medullary bone (Mb). Our findings revealed that supplementation with Akk powder increased the thickness and bone mineral content of Cb and Tb, while simultaneously reducing the volume and bone surface area of Mb. The increased activity of alkaline phosphatase, a marker of osteogenesis, and the decreased activity of tartrate-resistant acid phosphatase, a marker of osteoclastic activity, were observed in the Akk group. Dietary supplementation of Akk powder improved the immune microenvironment in the bone marrow by increasing osteogenic-related CD8+ T cells and decreasing osteoclastogenesis-related CD4+ T cells. Additionally, Akk powder supplementation significantly enriched the Lactobacillaceae family in cecum. The enhancement of bone development by Akk contributed to increased eggshell strength and thickness. These findings demonstrate the osteomodulatory effects of Akk in laying hens and the connections between bone physiology and eggshell quality, highlighting the importance of gut–bone communications in laying hens.

Reproductive biology of 58 fish species around La Réunion Island (Western Indian Ocean): first sexual maturity and spawning period

Reproductive biology of 58 fish species around La Réunion Island (Western Indian Ocean): first sexual maturity and spawning period

Accelerating sexual maturation of male Anastrepha ludens (Diptera: Tephritidae) fruit flies by adding two juvenile hormone analogues.

Improving the mating competitiveness and survival of sterile males are direct means to increase the effectiveness of the sterile insect technique (SIT). Some insecticide growth regulators, such as the juvenile hormone analogue (JHA) methoprene, have been used to improve the mating competitiveness of male tephritid flies by reducing their sexual maturation period. However, the application of methoprene reduces fly resistance to stress and decreases survival. Here, we compared the effects of methoprene and pyriproxyfen (PPF), another JHA, in Anastrepha ludens males. PPF is an insect growth regulator that exhibits higher negative effects on the larval molting process than methoprene or natural juvenile hormone. Both compounds were administered at two doses (0.05% and 0.10%) via the male diet immediately after emergence. Our results show that both PPF and methoprene reduced male sexual maturation. However, PPF-treated males exhibited a shorter maturation period and obtained more matings at a given age than methoprene-treated males. No significant differences were observed between the two PPF doses tested (0.05% and 0.10%). Male survival was equally reduced by the two compounds. Our results demonstrate that PPF accelerated sexual development without reducing the mating propensity of sterile male flies and can be used as a suitable alternative for methoprene. © 2023 Society of Chemical Industry.

Characterization of MicroRNA expression profiles in the ovarian tissue of goats during the sexual maturity period

BackgroundThe ovary is an important reproductive organ in mammals, and its development directly affects the sexual maturity and reproductive capacity of individuals. MicroRNAs (miRNAs) are recognized as regulators of reproductive physiological processes in various animals and have been shown to regulate ovarian development through typical targeting and translational repression. However, little is known about the regulatory role of miRNAs in ovarian tissue development during sexual maturity in goats. To comprehensively profile the different physiological stages of sexual maturation in goats, we performed small-RNA sequencing of ovarian tissue samples collected at four specific time points (1 day after birth (D1), 2 months old (M2), 4 months old (M4), and 6 months old (M6)). In addition, we used ELISAs to measure serum levels of reproductive hormones to study their temporal changes.ResultsThe results showed that serum levels of gonadotropin-releasing hormone, follicle-stimulating hormone, luteinizing hormone, oestradiol, progesterone, oxytocin, and prolactin were lower in goats at the D1 stage than at the other three developmental stages (P < 0.05). The secretion patterns of these seven hormones show a similar trend, with hormone levels reaching their peaks at 4 months of age. A total of 667 miRNAs were detected in 20 libraries, and 254 differentially expressed miRNAs and 3 groups of miRNA clusters that had unique expression patterns were identified (|log2-fold change|> 1, FDR < 0.05) in the 6 comparison groups. RT‒qPCR was employed to confirm that the expression pattern of the 15 selected miRNAs was consistent with the Illumina sequencing results. Gene ontology analyses revealed significant enrichment of GO terms such as cell proliferation regulation, epithelial cell development, and amino acid transport, as well as important signaling pathways including the MAPK signaling pathway, the PI3K-Akt signaling pathway, and the oestrogen signaling pathway. Further miRNA‒mRNA regulation network analysis revealed that 8 differentially expressed miRNAs (chi-miR-1343, chi-miR-328-3p, chi-miR-877-3p, chi-miR-296-3p, chi-miR-128-5p, chi-miR-331-3p, chi-miR-342-5p and chi-miR-34a) have important regulatory roles in ovarian cell proliferation, hormone secretion and metabolism-related biological processes.ConclusionsOverall, our study investigated the changes in serum hormone and miRNA levels in the ovaries. These data provide a valuable resource for understanding the molecular regulatory mechanisms of miRNAs in ovarian tissue during the sexual maturity period in goats.

Weather based forecasting model for emergence of Aprostocetus purpureus (Cameron) – a parasitoid of lac insect, Kerria lacca (Kerr)

Indian lac insect, Kerria lacca is a scale group beneficial insect which suffers by several natural enemies. The establishment of the relationship between the incidences of natural enemies on lac insects with weather variables is essential for formulating management strategies well in advance. The relationship between weather factors and the emergence of A. purpureus was studied from 2011–12 to 2020–21 on the rangeeni summer (baisakhi) lac crop. Correlation and regression analyses were done after pooling ten years data (2011-12 to 2020-21) during the critical lac growth period i.e. SMW 8 to SMW 20. The relative abundance of lac-associated fauna showed that three parasitoids ((Aprostocetus purpureus, Tachardiaephagus tachardiae, and Tyndarichus(=Parechthrodryinus) clavicornis)) and one predator (Eublemma amabilis) were abundant. Among them, A. purpureus recorded maximum percent infestation, which was 84% and 75% on ber and palas, respectively. Maximum number of A. purpureus was emerged during the sexual maturity period (8 to 20 SMW) of the summer lac crop. The incidence exhibited a significant negative correlation with maximum (Tmax) and minimum temperature (Tmin) and a significant positive correlation with morning and evening relative humidity (RH-II). Stepwise regression analysis showed Tmax and RH-II were the most important factors contributing to 68% variation in the incidence of A. purpureus on palas. The present study results indicated that environmental factors played a significant role in the incidence of parasitoids on lac insect.

PM 2.5 juvenile exposure–induced spermatogenesis dysfunction by triggering testes ferroptosis and antioxidative vitamins intervention in adult male rats

PM2.5 derived from automobile exhaust can cause reproductive impairment in adult males, but the toxic effects of PM2.5 exposure on reproductive function in juvenile male rats and its relationship with ferroptosis have not been reported. In this paper, 30-day-old juvenile male Sprague-Dawley (SD) rats were divided into four groups (blank control, vitamin control, PM2.5, and PM2.5+Vitamin). The blank control group was fed normally, and the vitamin control group was given intragastric administration of vitamins in addition to normal feeding. PM2.5 was administered via tracheal intubation. When the rats were treated for 4 weeks until reaching the period of sexual maturity. A mating test was performed first, and then their testicular and epididymal tissues were studied. Compared with control rats, juvenile male rats exposed to PM2.5 showed a decreased sperm count and fertility rate, redox imbalance, damaged mitochondria, a metabolic disorder of intracellular iron ions, and a significant rise in ferroptosis during the period of sexual maturity. After antioxidative vitamins intervention, the redox imbalance, metabolic disorder of intracellular iron ions, and ferroptosis were all alleviated, leading to the following conclusions: after being exposed to PM2.5 from automobile exhaust, male juvenile rats during the period of sexual maturity have significantly decreased reproductive function. The reproductive toxicity of PM2.5 is closely related to oxidative stress and ferroptosis. In addition, ferroptosis decreases and reproductive function is recovered to some degree after antioxidative vitamins intervention.Graphical abstract

The Importance of Adolescent Reproductive Organ Care: Tips and Tricks for Future Health

Adolescents entering puberty are distinguished by a period of sexual maturation and they are confronted with situations requiring adjustments to accommodate the occurring changes. Sexual maturity and changes in body shape greatly affect the psychological life of adolescents. In addition, sexual maturity also causes adolescents to become interested in the anatomy and physiology of their bodies. Apart from being attracted to himself, he also begins to feel attracted to peers of the opposite sex. Correct Information and Risk Preparedness: Early teens should get accurate and thorough knowledge about menstruation, reproduction, and sexually transmitted illnesses through reproductive health education. The target of the service is early youth, namely students of SD Muhammadiyah Tamantirto Yogyakarta, especially grades 4 and grade 5. The method used is lectures and questions and answers by providing health education about reproductive health as well as health care tips and tricks. The level of student satisfaction with this health education activity was high. 98% of the students were satisfied with literacy knowledge of reproductive health as well as health care tips and tricks carried out by this community service team. In the analysis of the the average knowledge, the level of the pretest results was 70.61 and the posttest results’ mean knowledge level is 74.77. There was a significant increase in the level of students' knowledge

Effects of adolescent ethanol exposure on adult nondrug reward seeking behavior in male and female mice.

Adolescent alcohol use is associated with an increased likelihood of developing an alcohol use disorder in adulthood, potentially due to the effects of alcohol exposure on reward-seeking behavior. However, it remains unclear whether adolescent drinking is sufficient to alter nondrug reward seeking in adulthood. As adolescence is a period of both brain and sexual maturation, which occur in a sex-dependent manner, males and females may be differentially sensitive to the consequences of adolescent alcohol exposure. The present study investigated whether adolescent ethanol exposure affected food reward taking and seeking in male and female adult mice. Male and female C57BL/6J mice underwent intermittent ethanol exposure (AIE) via vapor inhalation during early adolescence (28-42 days of age). At 10 weeks of age, the mice were trained in a conditioned place preference paradigm (CPP) for a food reward. We measured food consumption, CPP, and cFos expression in multiple brain regions following CPP testing. Data were analyzed using repeated measures analysis of variance with exposure (air vs. AIE), sex, and time as factors. AIE exposure increased food consumption during CPP training in adult male mice, but reduced pellet consumption in adult female mice. AIE exposure impaired CPP expression only in female mice. Despite these behavioral differences, exposure to the reward-paired chamber did not induce differential cFos expression following CPP testing in the prelimbic and infralimbic cortices or the nucleus accumbens core and shell. These findings indicate that adolescent ethanol exposure disrupted nondrug reward taking and seeking in adulthood in female mice and altered consumption in adult male mice.

The Influence of Calcium Intake During the Period of Sexual Maturation of Pullets on its Retention and Eggshell Quality of Laying Hens

The Influence of Calcium Intake During the Period of Sexual Maturation of Pullets on its Retention and Eggshell Quality of Laying Hens

Relative Abundance, Emergence Profile and Parasitization of Lac Insect (&lt;i&gt;Kerria lacca&lt;/i&gt;) Associated Fauna in Rangeeni Crops

Relative abundance, emergence profile and parasitization of parasitoids and predators associated with lac insect were recorded during rangeeni summer season (baisakhi) and rainy season (katki) lac crops on ber and palas under two different conditions viz., spray of fipronil + chlorothalonil and only chlorothalonil. It revealed that three parasitoids (Aprostocetus purpureus, Tachardiaephagus tachardiae, Tyndarichus clavicornis) and one predator Eublemma amabilis were abundant in both lac crops. Lac associated fauna were recorded more on lac crop sprayed with chlorothalonil only compared to fipronil + chlorothalonil on both crops on both lac hosts. Among the lac associated fauna, A. purpureus was recorded in more numbers in both crops and spray conditions. Maximum level of parasitization was recorded at the time of sexual maturity period (19 to 22 Weeks After Inoculation (WAI)) during baisakhi whereas in katki, at crop maturity period (16 to 19 WAI) on ber and palas.

Evaluation of Population Parameters of Seahorses in Areas with and without Tourism in Federal Marine Protected Areas in Northeast Brazil

In Brazil, there is the tourist attraction of interacting with seahorses, which occurs through raft rides, during which the animals are captured and displayed in glass containers to be photographed and filmed by tourists. Two federal protected marine areas where this activity takes place were monitored, Jericoacoara National Park (monitored area of 600 m2 ), in the state of Ceará, and Environmental Protection Area (EPA) Delta do Parnaíba (monitored area of 547 m2 ), in the state of Piauí. Between 2011 and 2015, in both PMAs, the active search for animals was carried out by snorkeling during low tide, and the only species found was Hippocampus reidi, with 1286 sightings of seahorses in the National Park and 602 in the EPA. Results such as the mean height at formation of the male brood pouch (11.35 and 11.52 cm at EPA and National Park, respectively), size at first sexual maturity (14.2 and 14.7 cm, respectively) and reproductive period throughout the year were very similar between the populations of the two protected areas. All sites in both PMAs suffered a significant reduction in seahorse population during the study, except for the site P2 in EPA where the seahorse numbers remained stable throughout the study.

Annual changes in ovarian development stages of farmed female red‐spotted grouper, Epinephelus akaara, and inducing sexual maturity using photoperiod manipulation

AbstractThis study aimed to investigate the correlation between melatonin and the reproductive mechanism of farmed female red‐spotted groupers, Epinephelus akaara. Through the reproductive cycle experiment, the sexual maturity period was determined to be from June to July, following which the spawning season occurred in August. In addition, kiss1, kiss2, and GPR54 mRNA expression levels peaked in January, whereas that of sbGnRH mRNA remained at high levels from January to May and decreased during the sexual maturity and spawning seasons. During the day–night cycle, a nocturnal rhythm of AANAT2 mRNA expression was observed in the brain, and AANAT2 mRNA expression showed a seasonal pattern with increased expression during summer compared with that in winter. A correlation between melatonin and reproduction‐related genes could not be observed via melatonin administration, and sexual maturity was observed to be more induced under long photoperiod conditions compared with short photoperiod conditions. These results indicate that the reproductive mechanism of the farmed female red‐spotted grouper is related to changes in photoperiod and melatonin, and further research is needed to clarify the reproductive mechanism. Our findings provide basic information for identifying the reproductive mechanisms of farmed E. akaara.

Hepatopancreas transcriptome analyses provide new insights into the molecular regulatory mechanism of fast ovary maturation in Macrobrachium nipponense

BackgroundMacrobrachium nipponense is an economically and ecologically important freshwater prawn that is widely farmed in China. In contrast to other species of marine shrimp, M. nipponense has a short sexual maturity period, resulting in not only high stocking densities, but also a reduced survival rate and increased risk of hypoxia. Therefore, there is an urgent need to study the molecular mechanisms underlying fast ovary maturation in this species.ResultsComparative transcriptome analysis was performed using hepatopancreatic tissue from female M. nipponense across five ovarian maturation stages to explore differentially expressed genes and pathways involved in ovarian maturation. In total, 118.01 Gb of data were generated from 15 transcriptomes. Approximately 90.46% of clean reads were mapped from the M. nipponense reference genome. A comprehensive comparative analysis between successive ovarian maturation stages generated 230–5814 differentially expressed genes. Gene Ontology (GO) enrichment was highly concentrated in the “biological process” category in all four comparison groups, and mainly focused on energy synthesis and accumulation, energy decomposition and transport. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment results showed that, among 20 significantly enriched KEGG pathways, nine were involved in the synthesis, degradation, and metabolism of carbohydrates, lipids, and other nutrient intermediates, suggesting that the hepatopancreas has an important role in energy supply during ovarian maturation. Furthermore, the “Insect hormone biosynthesis” pathway was found to have a dominant role in the development of the ovary from immaturity to maturity, supporting the hypothesis that ecdysteroid- and juvenile hormone-signaling pathways have an important role in hepatopancreas regulation of ovarian maturation.ConclusionTaken together, this study sheds light on the role of the hepatopancreas in the molecular regulation of ovary maturation in M. nipponense. The present study provided new insights for understanding the mechanisms of reproductive regulation in crustaceans.

Age-Related Interactions with Wind During Migration Support the Hypothesis of Developmental Learning in a Migrating Long-Lived Seabird

Wind patterns shape migratory pathways and detours of many procellariiform bird species that seasonally migrate between hemispheres. These seabirds are long-lived, and the period of immaturity is presumed to be a time of development and learning the environment, specifically how to use wind to their advantage. We assess how wind encountered by individual Great Shearwaters (Ardenna gravis) varies along the migration journey and compare responses between presumed mature and immature birds (early and late, respectively) in southbound migration and mature birds in northbound migration. We analyze modeled Argos locations from 71 individual tracks of migratory Great Shearwaters with concurrent U (East/West) and V (North/South) wind components. Migration in seabirds is well studied, but there is limited quantitative work measuring individual birds directly interacting with wind and their associated changes in flight behavior during migration. We show that Great Shearwaters made optimal use of winds, and that different age groups made decisions that exposed them to different wind constraints. Overall, Great Shearwaters derived positive responses from wind under most conditions and did not rely on a drifting strategy, which would be suggested if wind effect (difference between ground and airspeed) was predominantly positive during migrations. Instead, they appeared to use a compensating strategy to achieve an acceptable course and speed. The difference we observed in migration phenologies suggests that by migrating later, immature birds might travel the path of least resistance and experience flight conditions that are less risky furthering their ability to withstand a variety of wind conditions encountered later in life as done by adults, which migrate earlier and are subject to more variable flight conditions. We conclude that like other procellariiforms, a longer period of sexual maturity is required to enhance flight performance and mediate energy expenditure through experiential learning and increased fitness.

Two generations of meiotic gynogenesis significantly elevate homogeneity and confirm genetic mode of sex determination in bighead carp (Hypophthalmichthys nobilis)

Gynogenesis is an effective technique for establishing pure line and validating possible chromosomal mode of sex determination in fish. As one of the major aquaculture fish historically cultured in China, bighead carp (Hypophthalmichthys nobilis) is famous for its market value of the head, but slow in its genetic improvement due to a long period of sexual maturation. In this study, females of bighead carp (F0 dams) with fast growth and bigger head were chose to induce first and second generation of meiotic gynogenesis (GF1 and GF2 for short) by using UV-irradiated heterologous sperm of common carp (Cyprinus carpio). On average, diploid gynogens were obtained by cold shock with a survival rate of 7.36% for GF1 and 6.24% for GF2, respectively. Results of morphology comparison and parentage assignment showed that all survival gynogens were genetically derived from the dams. Compared with their F0 parents, heterozygosities of GF1 and GF2 gynogens decreased by 42% and 60% when analyzed using 50 SSRs, and by 35% and 53% when using 1505 SNP markers, respectively. Sexing of the GF1 and GF2 gynogens showed all-female genotypes and phenotypes when examined by male-specific DNA markers, histology section and morphology of gonads. Overall, large number of meiotic gynogens have been successfully induced in two consecutive generations, providing valuable resources for fast domestication and genetic improvement in bighead carp. Our evidence of sex ratios in both GF1 and GF2 gynogens also strongly supports a proposed chromosomal mechanism of sex determination (XX/XY) for this large-size cyprinid fish.

RNA interference of Argonaute-1 delays ovarian development in the oriental fruit fly, Bactrocera dorsalis (Hendel).

With the development of rapid resistance, new modes of action for pesticides are needed for insect control, such as RNAi-based biopesticides targeting essential genes. To explore the function of Argonaute-1 (Ago-1) and potential miRNAs in ovarian development of Bactrocera dorsalis, an important agricultural pest, and to develop a novel control strategy for the pest, BdAgo-1 was first identified in B. dorsalis. Spatiotemporal expression analysis indicated that BdAgo-1 had a relatively high transcriptional level in the ovarian tissues of adult female B. dorsalis during the sexual maturation period. RNA interference (RNAi) experiment showed that BdAgo-1 knockdown significantly decreased the expression levels of ovarian development-related genes and delayed ovarian development. Although RNAi-mediated silencing of Ago-1 led to a reduced ovary surface area, a subsequent oviposition assay revealed that the influence was minimal over a longer time period. Small RNA libraries were constructed and sequenced from different ovarian developmental stages of B. dorsalis adults. Among 161 identified miRNAs, 84 miRNAs were differentially expressed during the three developmental stages of the B. dorsalis ovary. BdAgo-1 silencing caused significant down-regulation of seven differentially expressed miRNAs (DEMs) showing relatively high expression levels (>1000 TPM (Transcripts per kilobase of exon model per million mapped reads)). The expression patterns of these seven core DEMs and their putative target genes were analyzed in the ovaries of B. dorsalis. The results indicate that Ago-1 and Ago-1-dependent miRNAs are indispensable for normal ovarian development in B. dorsalis and help identify miRNA targets useful for control of this pest.

Economic and biological features of young cattle of Kalmyk breed of different breed types

Domestic beef cattle breeding is faced with a difficult task to accelerate the development of the industry in the context of a course on import substitution, which involves not only increasing the volume of raw materials produced, but also improving the quality of products. The purpose of the research was a comparative test of new breed types of Kalmyk cattle with the study of biological and economic features in terms of the formation of reproductive traits and meat productivity, as well as the composition of proteins and lipids of meat, morphometry of muscle tissue in young animals for further improvement of the breed. Comprehensive researches on the economic and biological characteristics and meat production taking into account bioconversion of nutrients in feed products, the qualitative assessment of meat in relation to the histological organization of muscle tissue, amino acid and fatty acid composition of proteins and lipids of meat and given the economic effectiveness of growing of young Kalmyk breed of new factory types Aita and Voznesenovsky have been carried out under environment of the Southern Federal District. Analysis of data on the intensity of daily body weight gain for the entire period of control rearing has shown that castrated bullates of Voznesenovsky type have surpassed herdmates of Aita type by 27,6 g or 3,43 %. A similar situation has been observed among heifers of different types. Different terms of implementation of individual cycles of reproductive function in heifers have been established. Heifers of Voznesenovsky type differed in an earlier period of sexual maturity by 3,9–7,8 days, relative to heifers of Aita type. A comparative analysis of the economic and biological characteristics of castrated bullates and heifers of Kalmyk breed of different breed types has shown the superiority of young animals of Voznesenovsky breed type.