Hybrid breeding is a crucial approach in aquaculture for improving stock performance. This study systematically evaluated heterosis in hybrid offspring from a cross between the zig-zag eel (<i>Mastacembelus armatus</i>) and the tire track eel (<i>Mastacembelus favus</i>). The hybrids exhibited significantly superior growth performance and a higher survival rate than both parental populations. Physiological analyses revealed distinct advantages in digestive enzyme activity and intestinal tissue structure. Liver transcriptome sequencing revealed that most of the differentially expressed genes (DEGs) in the hybrids displayed non-additive expression patterns and were significantly enriched in pathways associated with growth hormone synthesis, insulin secretion and lipid metabolism. The upregulation of <i>igf2</i> and the downregulation of <i>socs1</i> were identified as key molecular drivers of enhanced growth. This multi-level analysis, spanning from phenotype to molecular mechanisms, sheds light on the heterogeneous basis of these hybrids and provides theoretical insights and practical guidance for breeding work with zig-zag eels and related species.
Crop Rotation Experiment was established on experimental facilities of the Institute for Engineering and Environmental Problems in Agricultural Production – branch of Agro-Engineering Centre VIM, Saint-Petersburg. The objective of the study was to consider the requirements for growing organic potatoes. In an experiment with potatoes (Solánum tuberosum) variety Udacha, the influence of 3 factors was studied: the effect of organic fertilizers; action of bio-fungicide; row spacing depth. The compost studied was produced in the Institute from chicken manure using an aerobic fermentation unit. Doses of composts corresponded to 0; 80; 110, 160 kg N/ha. Potato tubers were treated with a bio-fungicide using a sprayer installed on a potato planter, and the leaves were treated during the growing season. Organic technology for cultivating potatoes was developed at the institute and used in experiment. The experiment has been equipped with automated tools for collecting information. Weather conditions differed from each other during the experiment. In 2021, conditions were dry during the potato development period. Weather conditions in 2020 and 2022 were similar. Monitoring shows that deep cultivation of row spacing contributed to better absorption of precipitation. This created more convenient conditions for potato development. Compost helped to increase the content of mineral forms of nitrogen in the soil. Due to high soil fertility, the yield of standard potato tubers in the variant without compost and bio-fungicide reached the level of 20.3 – 20.5 t ha-1 in 2020 and 2022 and 13.4 tha-1 in 2021, a dry year. Compost provided a significant increase in potato yield from 4 to 9 tha-1, depending on the dose of compost and year. The array of experimental data was generated for 2017-2022. After mathematical processing, the dependence of potato yield on the hydro-temperature coefficient in May and the dose of compost used was obtained.
Shimaa A. Abdelbaky, Zakaria M. Zaky, Doha Yahia
et al.
Contamination of the environment with nano- and microplastic particles exerts a threatening impact on the aquatic ecosystems and sustainable catfish aquaculture. The presence of nanoplastics has been found to have a detrimental impact on both aquatic and terrestrial ecosystems. The present study examines the effect of polystyrene nanoplastics (PS NPs) on the DNA, erythrocytes, oxidative status and renal histology of catfish, in addition to the potential protective effects of <i>Chlorella vulgaris</i> bioremediation and selenium to hinder this effect. Six equal groups of fish were used as follows: Group 1 served as a control group and received water free from PS NPs; Group 2 was exposed to PS NPs at a concentration of 5 mg/L; Group 3 was exposed to PS NPs (5 mg/L) + selenium (1 mg/kg diet); Group 4 was exposed to PS NPs (5 mg/L) + <i>C. vulgaris</i> (25 g/kg diet); Group 5 was supplemented with <i>C. vulgaris</i> (25 g/kg diet); and Group 6 was supplemented with selenium (1 mg/kg diet). The exposure period was 30 days. The results indicated that PS NPs induced oxidative stress by significantly elevating malondialdehyde activities and slightly reducing antioxidant biomarkers, resulting in DNA damage, increased frequency of micronuclei, erythrocyte alterations, and numerous histopathological alterations in kidney tissue. Selenium and <i>C. vulgaris</i> significantly ameliorated the oxidative/antioxidant status, reducing DNA damage, micronucleus frequency, erythrocyte alterations, and improving the morphology of kidney tissue. Nevertheless, further research is needed for a profound understanding of the mechanism behind the toxicity of nano-microplatics in aquatic systems.
Fabio Akashi Hernandes, James Craig Cokendolpher, Luiz Carlos Pinho
Abstract Herein we report for the first time a schizomid for the Southern region of Brazil, Stenochrus portoricensis Chamberlin, 1922 (Schizomida: Hubbardiidae), found in association with termite nests. This is the southernmost record of any schizomid for the Neotropical region. We hypothesize that the species was recently introduced by the sudden population growth of Florianópolis - along with the intense touristic activity - which might have contributed to the inadvertent transportation of this species.
L. W. Cavalheiro, A. Antunes de Souza Santos, C. Bernhardt Fialho
Cambios longitudinales y ontogénicos en las pautas de alimentación de una especie insectívora de la familia Crenuchidae en arroyos del sur del Brasil
El género Characidium es el más rico en especies de la familia Crenuchidae y la subfamilia Characidiinae. Characidium pterostictum reviste una inmensa importancia debido a su amplia distribución en América del Sur, en especial en los sistemas hidrográficos del río Uruguay. El objetivo del presente estudio es describir la biología alimentaria de Characidium pterostictum en los arroyos de la cuenca del río Ijuí (sistema del río Uruguay) en el sur del Brasil, así como determinar las posibles variaciones espaciales y ontogénicas de su dieta. Se recogieron muestras en tres afluentes del río Ijuí. Se identificaron y cuantificaron los alimentos utilizando el método volumétrico y la frecuencia de presencia. Characidium pterostictum se caracterizó como un pez insectívoro, una especialización que ya se había observado en la subfamilia Characidiinae. Existe una ligera diferencia en las pautas de alimentación en función de las variaciones en la longitud estándar de los individuos y los sitios de muestreo. El análisis ontogenético demostró que Characidium pterostictum amplía el espectro alimentario a medida que se va desarrollando. El consumo de alimentos autóctonos (restos de insectos, efemerópteros, tricópteros y quironómidos) como principal componente de la dieta indica que esta especie de pez necesita la conservación intensiva de los cursos de agua en los que vive.
Veličković Tijana, Snoj Aleš, Bravničar Jernej
et al.
Artificial propagation and stocking of brown trout is a standard practice in recreational fishery management. In recent decades, the importance of maintaining intraspecific diversity and protecting locally adapted lineages has been recognized for the species' long-term survival. The first step in selecting donors for stocking involves distinguishing native trout from non-native and introgressed individuals. The established method for discerning Atlantic hatchery strains from the wild populations involves genetic screening of individual diagnostic SNPs and microsatellite assignment tests. This study, using Serbia's Panjica hatchery as an example, illustrates the proper conduct of routine genetic screening for identifying suitable donors for supportive stocking. The broodstock and reference populations were screened using mtDNA control region, LDH nuclear gene, and 12 microsatellite loci to assess the origin, diversity, and inbreeding levels. The analysis revealed only moderate contamination with Atlantic trout and showed the regional origin of the Danubian genes – over 50% of the broodstock was composed of non-introgressed Danubian individuals tracing their origin to the Zapadna Morava River system. Additionally, the study highlighted a considerable discordance between LDH locus and microsatellites in identifying introgressed individuals, raising concerns about the sole reliance on LDH locus for the identification of Atlantic genetic origin in nuclear DNA.
Yuan-Cheng Cheng, Cai-Han Xie, Yu-Chen Chen
et al.
Abstract Background Parental care benefits offspring but comes with costs. To optimize the trade-off of costs and benefits, parents should adjust care based on intrinsic and/or extrinsic conditions. The harm to offspring hypothesis suggests that parents should invest more in younger offspring than older offspring because younger offspring are more vulnerable. However, this hypothesis has rarely been comprehensively tested, as many studies only reveal an inverse correlation between parental care and offspring age, without directly testing the effects of offspring age on their vulnerability. To test this hypothesis, we studied Kurixalus eiffingeri, an arboreal treefrog with paternal care. We first performed a field survey by monitoring paternal care during embryonic development. Subsequently, we conducted a field experiment to assess the prevalence of egg predators (a semi-slug, Parmarion martensi) and the plasticity of male care. Finally, we conducted a laboratory experiment to assess how embryo age affects predation by P. martensi. Results Our results showed that (1) male attendance and brooding frequency affected embryo survival, and (2) males attended and brooded eggs more frequently in the early stage than in the late stage. The experimental results showed that (3) males increased attendance frequency when the predators were present, and (4) the embryonic predation by the semi-slug during the early was significantly higher than in the late stage. Conclusions Our findings highlight the importance of paternal care to embryo survival, and the care behavior is plastic. Moreover, our results provide evidence consistent with the predictions of the harm to offspring hypothesis, as males tend to care more for younger offspring which are more vulnerable.
Research primates may undergo surgical procedures making effective pain management essential to ensure good animal welfare and unbiased scientific data. Adequate pain mitigation is dependent on whether veterinarians, technicians, researchers, and caregivers can recognize and assess pain, as well as the availability of efficacious therapeutics. A survey was conducted to evaluate primate veterinary approaches to pain assessment and alleviation, as well as expressed challenges for adequately managing primate pain. The survey (<i>n</i> = 93 respondents) collected information regarding institutional policies and procedures for pain recognition, methods used for pain relief, and perceived levels of confidence in primate pain assessment. Results indicated that 71% (<i>n</i> = 60) of respondents worked at institutions that were without formal experimental pain assessment policies. Pain assessment methods were consistent across respondents with the majority evaluating pain based on changes in general activity levels (100%, <i>n</i> = 86) and food consumption (97%, <i>n</i> = 84). Self-reported confidence in recognizing and managing pain ranged from slightly confident to highly confident, and there was a commonly expressed concern about the lack of objective pain assessment tools and science-based evidence regarding therapeutic recommendations of analgesics for research primates. These opinions correspond with significant gaps in the primate pain management literature, including limited specific pharmacokinetic data and efficacy testing for commonly used analgesics in research primate species as well as limited research on objective and specific measures of pain in research primates. These results demonstrate that there are inconsistencies in institutional policies and procedures surrounding pain management in research primates and a lack of objective pain assessment methods. Demonstrating the gaps and challenges in primate pain management can inform guideline development and suggest areas for future research.
Marta Moya-Jódar, Giulia Coppiello, Juan Roberto Rodríguez-Madoz
et al.
Each year, tens of thousands of people worldwide die of end-stage organ failure due to the limited availability of organs for use in transplantation. To meet this clinical demand, one of the last frontiers of regenerative medicine is the generation of humanized organs in pigs from pluripotent stem cells (PSCs) via blastocyst complementation. For this, organ-disabled pig models are needed. As endothelial cells (ECs) play a critical role in xenotransplantation rejection in every organ, we aimed to produce hematoendothelial-disabled pig embryos targeting the master transcription factor <i>ETV2</i> via CRISPR-Cas9-mediated genome modification. In this study, we designed five different guide RNAs (gRNAs) against the DNA-binding domain of the porcine <i>ETV2</i> gene, which were tested on porcine fibroblasts in vitro. Four out of five guides showed cleavage capacity and, subsequently, these four guides were microinjected individually as ribonucleoprotein complexes (RNPs) into one-cell-stage porcine embryos. Next, we combined the two gRNAs that showed the highest targeting efficiency and microinjected them at higher concentrations. Under these conditions, we significantly improved the rate of biallelic mutation. Hence, here, we describe an efficient one-step method for the generation of hematoendothelial-disabled pig embryos via CRISPR-Cas9 microinjection in zygotes. This model could be used in experimentation related to the in vivo generation of humanized organs.
This research aimed to evaluate in vitro organic matter digestibility, fermentation characteristics and methane production of fruit and vegetable discards processed by solid state fermentation (SSF) by <i>Rhizopus</i> sp. Mixtures were composed of approximately 28% citric fruits, 35% other fruits and 37% vegetables. Fruit and vegetables were processed and fermented to obtain a stabilized product. Nutritional characterization and in vitro ruminal fermentation tests were performed to determine the effect of fungal bioconversion on digestibility, end products and gas production kinetics. Results indicate that SSF reduced organic matter and reducing sugars, while it increased crude protein and neutral detergent fiber, acid detergent fiber and neutral detergent insoluble protein. The in vitro gas production showed that SSF led to a reduction of the organic matter digestibility (<i>p</i> < 0.001), short chain fatty acids (SCFA; <i>p</i> = 0.003) and CH<sub>4</sub> (<i>p</i> = 0.002). SSF reduced the gas production from the insoluble fraction (<i>p</i> = 0.001), without modifying the production rate (<i>p</i> = 0.676) or the lag time (<i>p</i> = 0.574). Regarding SCFA profile, SSF increased acetic (<i>p</i> = 0.020) and decreased propionic (<i>p</i> = 0.004) and butyric (<i>p</i> = 0.006) acids proportions, increasing acetic to propionic (<i>p</i> = 0.008) and acetic plus butyric to propionic (<i>p</i> = 0.011) ratios. SSF succeeded in obtaining a stabilized material enriched in protein, but at the expense of a reduction of protein availability and organic matter digestibility. These changes should be considered before including them in a ruminant’s rations.
The main object of the present work was to evaluate the potential influence of the oak wood chips-wines contact time (30 and 60 days) on the evolution of the red wine phenolic composition during storage in bottle. Thus, global phenolic composition, color parameters, and individual anthocyanins of bottled red wines that had previously been in contact with oak wood chips during different times were analyzed. The results obtained demonstrates that in general, after 6 months of bottle storage, red wines with a previous oak wood chips contact time showed a more evident decrease on anthocyanin content, independently of the oak wood chips species used and toasting level. This tendency was also confirmed by the decrease in the values obtained for color intensity and a∗ (redness) CIELab coordinate value. However, a positive impact of oak wood chips contact time on wine hue color and b∗ (yellowness) CIELab coordinate values, was detected. Thus, after 6 months of bottle storage, red wines that were in a previous contact with oak wood chips (particularly during 60 aging days), exhibited lower color hue and b∗ values compared with control wine (without any oak wood chips contact).
The subpopulation of the bowhead whale Balaena mysticetus in the East Greenland-Svalbard-Barents Sea is endangered and until recently was believed to number in the tens. Recent studies have suggested that this subpopulation appears to be increasing. Here, we report on unusual aggregations of bowhead whales within the Fram Strait. We present opportunistic and effort-corrected observations of bowhead whales made from a small expedition vessel during cruises in June (2015-2018). Bowhead whales were sighted on 85 occasions (220-227 whales). An aggregation in 2015 (n = 84 whales) and high numbers in 2018 (n = 104-110) exceeded all previous records. The index of whale abundance was significantly higher in open water-leads (1.08-1.14 whales km-1 of survey effort) compared to areas with drift-ice (0.51-0.53 whales km-1). The highest abundance index was measured in deep waters where the bottom slope was relatively steep. Our findings highlight the temporal and spatial consistency of this species in areas with relatively loose ice cover (open water-leads) and steep slopes. It is unknown how global warming and resultant changes in ice-extent are going to affect bowhead whales within the Strait and whether they will find new feeding grounds due to an expanding open-ocean habitat. These slopes may become increasingly important to bowhead whales and Arctic top predators as a spring/early summer feeding ground. These relatively large numbers of bowhead whales are encouraging and can help direct future research monitoring programs to study the population ecology of these endangered whales.
Urodidae se registra por primera vez para China. Se describe la larva y pupa de Wockia magna Sohn, 2014. Se registra por primera vez el desarrollo del capullo de Urodidae y se discute el valor taxonómico de apoyo del capullo. Se proporcionan las fotos de la larva, crisálida y desarrollo del capullo, así como de las setas de las larvas del último estadio.
Zipf's law, and power laws in general, have attracted and continue to attract considerable attention in a wide variety of disciplines—from astronomy to demographics to software structure to economics to linguistics to zoology, and even warfare. A recent model of random group formation (RGF) attempts a general explanation of such phenomena based on Jaynes' notion of maximum entropy applied to a particular choice of cost function. In the present paper I argue that the specific cost function used in the RGF model is in fact unnecessarily complicated, and that power laws can be obtained in a much simpler way by applying maximum entropy ideas directly to the Shannon entropy subject only to a single constraint: that the average of the logarithm of the observable quantity is specified.
The relationship between fish market price and body size has not been explored much in fisheries science. Here, the mean market prices and fish body size were collected in order to examine the hypothesis that large fish, both among- and within-species, are being selectively targeted by fisheries because they may yield greater profit. Trophic levels, vulnerability to fishing and global landings were also collected because these variables may also be related to the market fish price. These relationships were examined using generalized additive models (GAM), which showed that, among species, fish market price was positively dependent on maximum total length (P = 0.0024) and negatively on landings (P = 0.0006), whereas it was independent of trophic level (P > 0.05) and vulnerability to fishing (P > 0.05). When the fish price vs. size relationship was tested within-species, large individuals were consistently attaining higher market prices compared to their medium and small-sized counterparts. We conclude that the selective removal of the larger fish, which is driven by their market price and to a lesser extent by their availability, may contribute to their overfishing.
<em>Solaenodolichopus</em> Verhoeff, 1924 is redefined to include <em>S. pruvoti</em> (Brolemann, 1931), <em>S. rubriventris</em> Verhoeff, 1928, <em>S. sulcatus</em> (Verhoeff, 1928), <em>S. teres</em> (Verhoeff, 1924), <em>S. vittatus</em> (Verhoeff, 1924) and <em>S. walesius</em> Verhoeff, 1928, each of which is redescribed. Lectotypes are designated for <em>S. sulcatus</em>, <em>S. teres</em>, <em>S. vittatus</em> and <em>S. walesius</em>. <em>Parwalesoma</em> Verhoeff, 1937 is synonymised with <em>Solaenodolichopus</em> and <em>S. vittatus dorsalis</em> (Verhoeff, 1924) with <em>S. vittatus vittatus</em> (Verhoeff, 1924).