Transposon-induced epigenetic silencing in the X chromosome as a novel form of dmrt1 expression regulation during sex determination in the fighting fish

Background Fishes are the one of the most diverse groups of animals with respect to their modes of sex determination, providing unique models for uncovering the evolutionary and molecular mechanisms underlying sex determination and reversal. Here, we have investigated how sex is determined in a species of both commercial and ecological importance, the Siamese fighting fish Betta splendens. Results We conducted association mapping on four commercial and two wild populations of B. splendens. In three of the four commercial populations, the master sex determining (MSD) locus was found to be located in a region of ~ 80 kb on LG2 which harbours five protein coding genes, including dmrt1, a gene involved in male sex determination in different animal taxa. In these fish, dmrt1 shows a male-biased gonadal expression from undifferentiated stages to adult organs and the knockout of this gene resulted in ovarian development in XY genotypes. Genome sequencing of XX and YY genotypes identified a transposon, drbx1, inserted into the fourth intron of the X-linked dmrt1 allele. Methylation assays revealed that epigenetic changes induced by drbx1 spread out to the promoter region of dmrt1. In addition, drbx1 being inserted between two closely linked cis-regulatory elements reduced their enhancer activities. Thus, epigenetic changes, induced by drbx1, contribute to the reduced expression of the X-linked dmrt1 allele, leading to female development. This represents a previously undescribed solution in animals relying on dmrt1 function for sex determination. Differentiation between the X and Y chromosomes is limited to a small region of ~ 200 kb surrounding the MSD gene. Recombination suppression spread slightly out of the SD locus. However, this mechanism was not found in the fourth commercial stock we studied, or in the two wild populations analysed, suggesting that it originated recently during domestication. Conclusions Taken together, our data provide novel insights into the role of epigenetic regulation of dmrt1 in sex determination and turnover of SD systems and suggest that fighting fish are a suitable model to study the initial stages of sex chromosome evolution.

Microverme da aveia como estratégia alimentar na larvicultura do Betta splendens

A larvicultura é um período crítico na produção de peixes ornamentais, devido às necessidades produtivas e nutricionais das larvas nos primeiros dias de vida. O fornecimento de alimento vivo é essencial para a sobrevivência das larvas, sendo a Artemia sp. o alimento mais utilizando, apensar de representar custo elevado. Tornando necessária a busca por alimentos vivos de menor custo como o nematóide microverme da aveia. O presente trabalho foi desenvolvido com o objetivo de avaliar, por meio de índices de crescimento, desenvolvimento e sobrevivência, o fornecimento do microverme de forma exclusiva ou associado a artêmia e plâncton para larvas Betta splendens. As larvas alimentadas com microverme e artêmia apresentaram maior peso final, comprimento final, ganho em comprimento, maior taxa de desenvolvimento específico e sobrevivência. A taxa de uniformidade do lote no tratamento que recebeu apenas microverme não diferiu dos demais tratamentos, no entanto, as larvas submetidas ao regime alimentar com microverme e artêmia apresentaram melhor taxa de uniformidade quando comparas as que foram alimentadas com microverme e plâncton. A estratégia alimentar visando fornecer microverme e artêmia de forma conjunta promoveu os melhores índices de crescimento, desenvolvimento e sobrevivência na larvicultura inicial do peixe ornamental Betta splendens.

Masculinizing Effects of Chrysin-Loaded Poloxamer Micelles on Siamese Fighting Fish

Siamese fighting fish (Betta splendens) are freshwater fish that are commonly found in Thailand and other Southeast Asian countries. In the present study, chrysin-loaded polymeric micelles (CPs) were developed and investigated for the masculinizing effects, survival rate, growth indices, and toxicity on Siamese fighting fish. CPs were prepared using a poloxamer. The micelle system of CPs that were formed at a chrysin-to-polymer ratio of 1:2 was found to be the most suitable monodispersed system and exhibited a nanosized diameter (74.2 ± 1.6 nm) with a narrow size distribution (0.288 ± 0.012). In vivo studies were performed using Siamese fighting fish larvae as animal models. In the in vivo toxicity study, the fish larvae were immersed in aqueous systems containing CPs that had five different chrysin concentrations of 1, 10, 100, 1000, and 10,000 ng/mL for 24, 48, and 72 h. Blank polymeric micelles and water were used as controls. The in vivo masculinization effect of CPs with different chrysin concentrations on the fish larvae was evaluated after 5 weeks of exposure. The results demonstrated that CPs with a chrysin concentration of 1000 ng/mL showed a masculinization effect of 94.59 ± 2.76% with a high fish larvae survival rate of 72.45 ± 5.09% and low toxicity. It was concluded that the developed CPs had a significant effect on the sex reversal of Siamese fighting fish larvae with a high survival rate.

Occurrence of two abdominal neurofibromas in a specimen of Betta splendens

En este trabajo describimos dos neurofibromas en Betta splendens estudiados con microscopía óptica, inmunohistoquímica y microscopía electrónica. El espécimen estudiado, que pertenecía a un criador privado, presentaba marcada distensión abdominal, fue trasladado para diagnóstico al Laboratorio de Inmunología y Patología de Organismos Acuáticos de la Universidade Federal do Rio Grande – FURG. Fue diagnosticado como neurofibroma, positivo para el anticuerpo contra proteína S-100. Con microscopia electrónica, mostraba signos de degeneración en algunas células y contenía mastocitos distribuidos regularmente en la masa neoplásica. Con inmunohistoquímica confirmamos la histogénesis de la neoplasia, en la que existen dos neurofibromas, y con microscopía electrónica confirmamos que las células granulares que se encuentran entre el tejido neoplásico son MC.

ẢNH HƯỞNG CỦA HORMONE 17α - METHYLTESTOSTERONE BỔ SUNG VÀO THỨC ĂN LÊN TĂNG TRƯỞNG, CHIỀU DÀI CÁC VÂY, TỶ LỆ SỐNG VÀ TỶ LỆ ĐỰC HÓA CỦA CÁ LIA THIA (Betta splendens Regan, 1910)

Cá lia thia hay cá xiêm đá (Betta splendens) là một loài cá cảnh nước ngọt đặc trưng được nuôi làm cảnh hoặc giải trí thông qua hình thức chọi cá. Nghiên cứu này nhằm tìm ra liều lượng hormone 17α - Methyltestosterone (17α - MT) thích hợp bổ sung vào thức ăn để nâng cao tỷ lệ đực của cá lia thia. Cá bột sau khi hết noãn hoàng cho ăn thức ăn có bổ sung hormone 17α - MT liên tục trong 21 ngày với liều lượng 0, 20, 40 và 60 mg 17α - MT/kg thức ăn, tương ứng với nghiệm thức NT1, NT2, NT3 và NT4. Cá giống được nuôi tiếp tục đến 60 ngày tuổi để xác định tăng trưởng, tỷ lệ sống và tỷ lệ chuyển giới tính trên cá. Kết quả cho thấy tăng trưởng và tỷ lệ sống thì khác biệt không có ý nghĩa thống kê giữa các nghiệm thức (p>0,05). Tỷ lệ đực và chiều dài các vây ở NT3 cao hơn có ý nghĩa thống kê so với NT1 và NT2 (p<0,05), tuy nhiên khác biệt không có ý nghĩa thống kê so với NT4 (p>0,05). Nghiệm thức NT3 đạt tỷ lệ đực hóa (93,8%), hiệu suất đực hóa (84,6%) cao nhất và khác biệt có ý nghĩa thống kê giữa các nghiệm thức (p<0,05). Nghiên cứu này cho thấy bổ sung hormone 17α - MT vào thức ăn với liều lượng 40 mg 17α - MT/kg sẽ làm tăng tỷ lệ cá lia thia đực. ABSTRACT Lia thia fish commonly called the Siamese fighting fish (Betta splendens) is a specific freshwater aquarium fish, which raising as pet or for entertainment through fish fighting. This study aimed to find out the appropriate dosage of 17α - Methyltestosterone (17α - MT) hormone supplemented into feed to enhance masculinization rate of Siamese fighting fish. Frys after completing yolk digestion were fed with 17α - MT supplemented feed continuously for 21 days at dose of 0, 20, 40 and 60 mg 17α - MT per kg of feed, respectively treatment of NT1, NT2, NT3 and NT4. Fingerlings were kept being grown for up to 60 days of age to determine the growth, survival and transsexual rates on fish. The results showed that growth and survival rates of fish were not significantly different among treatments (p>0.05). Male rate and the fin lengths of fish in treatment of NT3 were statistically higher than those treatment of NT1 and NT2 (p<0.05); however, there were not significant difference compared to treatment of NT4 (p>0.05). Masculinization rate (93,8%) and masculinizing efficiency (84,6%) in treatment of NT3 were highest and there was statistically significant difference among the treatments (p<0.05). This research showed that supplement of 17α - MT into the feed at a dose of 40 mg 17α - MT per kg of feed increased the rate of male Siamese fighting fish.

CẢI TIẾN VIỆC ĐỰC HÓA CÁ XIÊM (Betta splendens Regan, 1910) BẰNG CÁCH NGÂM TRONG 17α-METHYLTESTOSTERONE

Cá xiêm (Betta splendens) 1 ngày tuổi được đực hóa bằng cách ngâm trong túi polyethylene chứa 17α-methyltestosterone (17α-MT) ở các nồng độ 2,5; 5,0 và 7,5 mg/L có bơm oxy (thể tích oxy: thể tích nước bằng 2:1), mật độ 150 con/L trong 4 giờ. Kết quả cho thấy, tỷ lệ đực và đực hóa tăng khi tăng nồng độ hormone, với nồng độ 2,5 mg 17α-MT/L cá đạt tỷ lệ đực, tỷ lệ đực hóa là 88,89% và 78,26%. Nồng độ 5,0 mg 17α-MT/L và nồng độ 7,5 mg 17α-MT/L đạt tỷ lệ đực, tỷ lệ đực hóa là 100%. Khác biệt không có ý nghĩa (p>0,05) về tăng trưởng chiều dài và khối lượng của cá xiêm. Tỷ lệ sống 60 ngày sau khi nở là 54 - 89,89%, tỷ lệ sống giảm khi tăng nồng độ hormone 17α-MT trong nước ngâm. Kết quả cho thấy, nồng độ 2,5 mg 17α-MT/L là liều tối ưu để áp dụng chuyển đổi cá xiêm đực. Nồng độ 2,5 mg 17α-MT/L cá đạt tỷ lệ sống, hiệu suất đực hóa cao nhất là (86,22%, 76,81%). Với nhiều ưu điểm như đơn giản, chi phí thấp và có thể áp dụng ở mọi nơi nên có thể sản xuất cá xiêm đực bằng cách áp dụng phương pháp ngâm cá trong hormone 17α-MT với nồng độ 2,5 mg/L để đạt hiệu quả kinh tế tối ưu cho người nuôi. ABSTRACT The siamese fighting fish (Betta splendens) at one day old were masculinized by immersion in a polyethylene bag containing 17α-methyltestosterone (17α-MT) at concentrations of 2,5; 5,0 and 7,5 mg/L with oxygen pump (volume oxygen: water volume is equal to 2:1), density is 150 fish/L in 4 hours. The results showed that the male and masculinization ratios increased when the hormone concentration was increased, with a concentration of 2,5 mg 17α-MT/L, the male rate and masculinisation rate was 88,89%, and 78,26% respectively. Concentration of 5,0 mg 17α-M/L and concentration of 7,5 mg 17α-MT/L reached the male rate, the masculinization rate was 100%. The difference was not significant (p>0,05) in terms of length and weight growth of siamese fighting fish. The survival rate of 60 days after hatching was 54 - 89,89%, the survival rate decreases when the concentration of 17α-MT hormone in immersion water increases. The results showed that, concentration of 2,5 mg 17α-M/L was the optimal dose for converting male siamese fighting fish. Concentration of 2,5 mg 17α-MT/L, fish achieved the highest survival rate, masculinization efficiency respectively rate (86,22%, 76,81%). With many advantages such as simplicity, low cost and applicability everywhere, it is possible to produce male siamese fighting fish by applying the method of immersion fish in the hormone 17α-MT with a concentration of 2,5 mg/L to achieve efficiency economic efficiency optimal for farmers.

The effect of enriched cyclopoid copepods on the coloration and feeding rate of Betta splendens

Copepods with a wide range of sizes, species, and nutritional compositions are preferred as live food for rearing of Betta splendens larvae. This research focuses on evaluating the efficiency of copepod enrichment diets in improving the coloration and feeding rate of B. splendens. Copepod were enriched with Chlorella sp. (T1), capsicum (T2), mixed vegetable (carrot + spinach), (T3), yeast (T4) and rice bran (T5) in 24 hours prior the feeding tests. As a result, proximate analysis of enriched-copepods showed that T1 (70.88±0.41) has highest protein content and T5 (22.01±0.59) has the highest lipid content. The specific growth rate and survival rate of B. splendens was highest in the treatment T1 (2.56±0.07%; 91.11±1.92%) and followed closely by T3 (2.49±0.51%; 85.55±8.39%). Feeding rate, T3 (70.08±3.88%) presented highest rate compared to other treatments. The different enrichment diets used were significantly impact the coloration test on body of L* value (P=0.001, P<0.05), T3 (66.11±3.60) appeared darker in color in contrast to others. As for a* value, the coloration was not impacted with the use of different enrichment on copepods (P=0.158, P>0.05) was detected for T1 (2.84±0.73) that gave a redder shade than other treatments did. T3 (2.40±0.30) exerted a more yellowish shade than the rest for b* value with a significant difference (P=0.015, P<0.05). The current study demonstrates that, rice bran, capsicum and mixed vegetable enrichment (carrot and spinach) have the potential to be an effective means of increasing B. splendens coloring and feeding rate. This potential diet can be further used as a substitution to artificial foods in producing sustainable culture of ornamental fish in the aquaculture industry.

Effects of Different Types of Feed on the Growth and Survival Rate of Betta splendens

Betta fish (Betta splendens) are freshwater ornamental fish that is very popular because it’s beautiful colors and unique behavior. This study aims to determine the growth measuring weight and length as well as the survival rate of betta fish seeds by providing different types of food that was conducted in door at Tulungagung, East Java, Indonesia. The study was experimentally designed with completely randomized design consisting of 3 treatments and 4 replications. The treatments A was fed with Tubifex sp., treatment B with artificial food (pellets), and treatment C was consisted of a combination of Tubifex sp., and artificial food. The test fish were 30 days old with a stocking density of 5/plastic bucket, where feeding was done ad-libitum. The study was conducted for 42 days. The parameters measured in this study were the growth in absolute weight and absolute length and its survival rate. Observations were analyzed using One Way Analysis of Variance (ANOVA) and further tests were carried out using the Duncan test. The results show that different feeding strategies had a significant effect on the growth of absolute weight and absolute length, and had no significant effect on the survival rate of betta fish. Water quality parameters measured include an average temperature was valued at 25.01oC-25.87oC, while the average pH was 8.42-8.47, and average dissolved oxygen (DO) was 4.13-4.17 mg/L.

PELATIHAN PEMANFAATAN MEDIA SOSIAL INSTAGRAM SEBAGAI MEDIA PEMASARAN IKAN BETTA SPLENDENS DAN BRANDING BISNIS DI KELURAHAN SUMBERSARI KOTA MALANG

Selama hampir satu tahun terakhir, pandemi virus corona telah mengubah pola kehidupan masyarakat di berbagai bidang, termasuk perekonomian dan bisnis, sosial, politik, pendidikan dan teknologi. Di tengah pandemi saat ini, pelaku usaha baik kecil, menengah dan besar harus berpikir keras dalam menjalankan usahanya. Pemanfaatan teknologi yang dibarengi dengan pemasaran dan branding bisnis produk melalu media sosial menjadi solusinya. Tak sedikit pelaku usaha memanfaatkan media sosial Instagram untuk menjual produknya itu, akan tetapi banyak juga persoalan yang dihadapi dalam pemanfaatan jejaring tersebut. Tujuan pengabdian masyarakat ini adalah untuk menganalisa sejauh mana peran media sosial Instagram sebagai media pemasaran dan branding bisnis di era pandemic covid 19 saat ini dan mengambil tempat di peternak Ikan Betta Splendens. Instagram sebagai salah satu media sosial di Indonesia yang memiliki banyak penggemar disinyalir akan membantu pemasaran dan branding bisnis kepada para pelaku usaha. Karena di era pandemi saat ini tidak hanya pengusaha kecil saja yang terkena dampak tapi juga pengusaha besar mengalami dampak kelesuan di penjualan produknya. Media sosial instagram sebagai salah satu sarana dalam melakukan promosi penjualan yang mudah dan efektif, instagram juga memiliki banyak keuntungan bagi pemasar, salah satunya adalah pemasar atau pelapak tidak perlu mengeluarkan uang untuk biaya promosi produk mereka, dengan begitu pelaku usaha bisa melakukan promosi sepuasnya agar produk mereka bisa menguasai pasar. Hal ini juga sebagai upaya meningkatkan penjualan produk lokal di tengah pandemic khususnya ikan Betta Splendens. Kata Kunci : Media Sosial Instagram, Media Pemasaran, Branding Bisnis