Judul: Potensi bakteri agarolitik sebagai penyedia enzim agarase eksogen untuk memperbaiki pertumbuhan juvenil abalon (Haliotis asinina Linn. 1758)
Abstrak: There is a great potential of using probiotics in aquaculture to increase growth rates and improve nutritional status of cultured animals. The aims of this research were to isolate and select agarolytic bacteria, to identify isolates based on physiological, biochemical and molecular properties, to analyze agarase activity of the isolates, to evaluate colonization ability of agarolytic isolates in the gastrointestinal tract of abalone, and to analyze the potency of Alg3.1-Abn1.2 bacterial strains as exogenous agarase producer to improve growth of abalone. Selection of agarolytic bacteria as probiotic was based on criteria of their antibiotics resistance, degree of agar liquefaction, and growth rate. Dinitrosalysilic acid was used to measure in vitro and in situ agarase activity. Viable cell count was used to determine whether the probionts could colonize gastrointestinal tract of abalone. Growth performance of gnotobiotic and normal abalone were evaluated and compared with abalone fed cake-Gracilaria supplemented with probiotic strains. The result of isolation can be achieved 14 agarolytic bacteria. Seven of them showed antibiotic resistance. Based on their growth rate, degree of agar liquefaction and qualitative agarolytic activity were carried out three isolate that potential as exogenous agarase producers, i.e. Alg4.2, Alg3.1 and Abn1.2 isolates. These isolates were identified as Vibrio. The ability of Alg3.1 strain to degrade agar was higher than the others, whereas the highest starch degradation was achieved by Abn1.2 strain. All isolates showed high capacity to degrade casein. Generally, the degree of carbohydrate and protein hydrolysis were increased up to 48 h of incubation. In vitro agarase activity of mix culture Alg3.1-Abn1.2 (0.593 nkat/mL) was higher than that of single culture of Alg3.1 (0.489 nkat/mL), Alg4.2 (0.423 nkat/mL) and Abn1.2 (0.411 nkat/mL). So the mix culture was chosen as candidate of probiotic. Abalone fed diet supplemented with mix culture of Alg3.1-Abn1.2 strains exhibited higher growth rate compared to that of abalone fed standard diet under laboratory conditions. The increasing of biomass of gnotobiotic and normal abalone supplemented with Alg3.1-Abn1.2 strains were higher 32.22 and 11.09% respectively than that of gnotobiotic and normal abalone fed standard diet. The improving of gaining daily shell length of gnotobiotic and normal abalone supplemented with probiotics were higher 24.17 and 21.88% than that of abalone fed unsupplemented diet. The efficiency and the feed conversion of abalone which supplemented with Alg3.1-Abn1.2 strains was better than that of control abalone. Application of Alg3.1-Abn1.2 strains as diet increased the activity of agarase and amylase exogen in the abalone digestive tract. The number of culturable cell reisolated from abalone fed probiotic-supplemented cake for 14 days was 106- 107 cfu/g.
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Judul: Genetic Improvement of Abalone Through Hybridization
Abstrak: Abalon merupakan kelompok moluska laut, kelas Gastropoda, famili Haliotidae dari genus Haliotis yang hidup pada zona intertidal. Sepuluh dari 100 spesies abalon yang tersebar di lautan dianggap memiliki nilai komersial, nilai ini stabil pada harga ±19 USD/Kg. Indonesia memiliki 2 spesies berupa Haliotis asinina serta Haliotis squamata. Dua spesies ini memiliki kelebihan dan kekurangan yang saling bertolak belakang. Penelitian ini bertujuan menganalisis performa hasil hibridisasi antara H. asinina dengan H. squamata dan resiproknya pada parameter fertilization rate (FR), hatching rate (HR), survival rate (SR), dan pertumbuhan larva. Perlakuan penelitian ini sebanyak 4 perlakuan dengan 3 kali pengulangan menggunakan Rancangan Acak Lengkap (RAL). Hasil perlakuan persilangan H. squamata dan H. asinina (SA) menunjukkan tingkat pembuahan di bawah nilai heterosis untuk perlakuan AS dan nilai yang tidak berbeda nyata untuk perlakuan resiproknya (SA) dengan keturunan H. Asinina dengan nilai 62%, tingkat kelangsungan hidup yang tidak berbeda nyata untuk SA dengan keturunan H. Asinina dengan nilai 60%, sedangkan untuk pertumbuhan dari perlakuan SA di atas nilai heterosis kedua tetuanya atau bersifat heterobeltiosis dengan nilai pertumbuhan panjang 63 μm dan lebar 70 μm. Hasil ini mengindikasikan peningkatan kualitas genetik terutama dalam parameter pertumbuhan larva dibandingkan tetuanya. Hasil penelitian ini dapat digunakan sebagai acuan dalam pengujian komprehensif pada berbagai lingkungan budidaya yang berbeda., Abalones are a group of marine molluscs, class Gastropods, family Haliotidae from the genus Haliotis that live in the intertidal zone. Ten out of 100 abalone species found in the oceans are considered to have commercial value, this value is stable at ±19 USD/Kg. Indonesia has two species, Haliotis asinina and Haliotis squamata. These two species have contradictory advantages and disadvantages. This study aimed to analyze the performance of hybridization results between H. asinina and H. squamata on the parameters of fertilization rate (FR), hatching rate (HR), survival rate (SR), and larval growth. The treatment of this study was 4 treatments with 3 repetitions using a Completely Randomized Design (CRD). The results of the cross treatment of H. squamata and H. asinina (SA) showed that the fertilization rate was below the heterosis value for the AS treatment and the value was not significantly different for the SA treatment with the H. asinina offspring with a value of 62%, the survival rate was not significantly different for sa with the offspring with a value of 60%, while for the growth of the SA treatment above the heterosis value of both parents or heterobeltiosis with a growth value of 63 μm in length and 70 μm in width. These results indicate an increase in genetic quality, especially in the growth parameters of the larvae compared to their parents. The results of this study can be used as a reference in comprehensive testing in various different cultivation environments.
Keyword: hybridization, abalone, haliotis asinina, haliotis squamata

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