Judul: Sex Reversalikan nila menggunakan madu dan analisis ekspresi gen aromatase
Abstrak: The use of synthetic steroid hormones to produce monosex populations of tilapia for intensive productive systems may lead to environmental and public health concerns. Such a situation is derived from the fact that female tilapine species have a high fecundity, generally reproducing at a small size and exhibiting stunted somatic growth at higher densities, while male tilapias exhibit faster growth rates and are often the preferred gender for monosex aquaculture.The study was conducted to determine the effect of immersion Nile tilapia larvae in water containing different honey source on male fish percentage and aromatase gene expression. In the first experiment, in a total of 30 tilapia larvae at 12 days posthatch were immersed in the water containing honey derived from the forest, cultured and mangrove bees, with a dose of 10 mL/L water for 10 hours. Fish were then maintained in the same condition for 2 months. The results showed that percentage of male fish immersed by different honey was similar (p>0.05), and all treatment was significantly different with the control (p<0.05). In the second experiment tilapia larvae were immersed in two bioactive compounds of honey, namely chrysin and potassium solution in a dose of 20 mg/L and 0.026 g/L, respectively, to verify the materials of honey that affects sex differentiation in Nile tilapia. The results showed that both compounds increased male fish percentage compared to that of control (p<0.1). This indicated that chrysin and potassium were involved in Nile tilapia sex reversal. Growth, survival and biomass of honey bee treated fish were similar with the control (p>0.05), while chrysin and potassium treated fish have lower survival rate than that of control (p<0.1). The lower survival rate maybe caused slightly higher specific growth in the chrysin and potassium treated fish compared to control (p<0.1). Furthermore, RT-PCR analysis showed that honey bee, chrysin and potassium down-regulated gonadal-type aromatase gene expression at 12 hours post immersion. Thus, honey can be use to sex reverse of Nile tilapia, and evolved the gonadal-type aromatase expression.
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Judul: Efektivitas Ekstrak Tepung Testis Sapi Dalam Alih kelamin Ikan Nila, Oreochromis Niloticus L. Melalui Teknik Perendaman
Abstrak: Monosex fish stocks are desirable in aquaculture in order to control reproduction and select the gender that have faster growth characteristics in a particular species. Synthetic steroids are commonly used to sex-reverse tilapia but because of their potential hazards and not recommended in Indonesia; the use of new natural compound is a potential alternative to be explored. Bull testes meal extract (BTME) had knowed containing natural testosterone hormone which can used on sex reversal in fish. The objective of this study was to determine the efficacy of a short-term immersion procedure for masculinizing Nile tilapia,_Oreochromis niloticus. Two androgens hormone were evaluated: 17a-methyltestosterone as control part (synthetic androgens) and the other is BTME as natural androgen. Exposure (8 h) on 4 and again on 7 days post-fertilization to 17a-methyltestosterone at 500 μg/ l successfully masculinized fry in all replicated experiments, resulting in 81,11% respectively. Immersions in BTME at 1 ml/l (Experiments A) resulted in significantly skewed sex ratios in (68,89 %), and Experiments B (3 ml/l) resulted in 75,56 % males; and Experiments C (5 ml/l) resulted in 85,56 % males. Although further research and refinement is needed, immersion of Nile tilapia in BTME may provide a practical alternative to the use of natural steroid-treated immersion. Furthermore, when compared with current techniques for steroid-induced sex inversion of tilapia, short-term immersion reduces the period of time that workers are exposed to anabolic steroids.
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Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf