Potential of using tropical brown macroalgae sargassum cristaefolium meal in the diets for juvenile white shrimp (litopenaeus vannamei)

The objectives of this study were to evaluate the effect of different dietary levels of tropical marine brown macroalgae, Sargassum cristaefolium meal (SCM) on growth performance and feed utilization efficiency of juvenile white shrimp, Litopenaeus vannamei (mean initial weight 2.65±0.1 g). The algae were collected from Bandengan Coast, Jepara, Indonesia. The study used a completely randomized design with 5 treatments of dietary different S. cristaefolium meal levels (0, 10, 20, 30, and 40 g algae meal/kg feed) in triplicates. The results showed that the different levels of dietary SCM did not significantly affect (P>0.05) average daily growth (ADG;.204-224 mg/day) and survival (80-97%) of the shrimp after a 42-day feeding period. However, the test diets significantly affected (P<0.05) feed intake (FI), feed conversion ratio (FCR), and protein efficiency ratio (PER). Better FCR (2.13) and PER (1.34) was found by the diet with 2% SCM compared to the control diet (no SCM) (FCR 3.42 and PER 0.81). This finding indicates that the supplement of dietary 2% SCM (20 g/ kg feed) can increase the feed utilization efficiency up to 62% or reduce the FCR up to 38% without any adverse in growth performance

Prospect of Using Bacterial Bio-formulation to Suppress Bacterial Leaf Blight of Rice: a Case Study in Cianjur, West Java

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a major disease of rice in Indonesia which remains difficult to be controled. A number of bacterial isolates had been collected and screened for their ability to antagonize Xoo disease. Six isolates with the highest antagonistic potential and wide spectrum were chosen for studies based on their ability to control the disease. Bio-formulations consisted of single or mixtures (consortium) of the bacterial antagonists were formulated and tested for their effectiveness to control BLB under field trials in Cianjur, West Java. Efficacy of the bio-formulations against the disease on different rice cultivars varied significantly with HDB reductions ranging from 10.5% to 29.4% among the cultivars tested in the WS 2010/2011. The mixture of A6 + A8-bentonite showed a good ability to reduce BB infestation by up to 25%. Performance of the A6+A8-bentonite formulation also exceeded those of the individual isolate formulations, such as Burkholderia spp. E76-bentonite and S. marcescens SKM-kaolin. Application of the bacterial mixture formulation did not affect significantly on rice plant height, number of tillers, and weight of 1000 grains, but increased grain yield up to 8%. This study showed that the advantages of single or mixed cultures were apparent and further evaluation for application of bio-formulation need to be done under more intensive field conditions

Karakterisasi dan Identifikasi Isolat Bakteri Endofitik Penghambat Jamur Patogen Padi

Disease caused byfungal pathogens often causing damage on rice crop. Thisstudy was aimed to characterize 10 endohytic bacterial isolatesin suppression of rice pathogenic fungi. Characterization by invitro test showed several endophytic isolates effective againstfungal pathogen Rhizoctonia solani (Rs) and Pyriculariaoryzae (Po). The bacterial culture filtrates could inhibit radialgrowth of fungal colonies with the Rs ranged percentageinhibition of 32.9-99.4%, whilst inhibition against Po wereranged from 3-98.2%, respectively. Based on chitinase assay,it was indicated that gram negative bacteria of E 76 isolateproduced clear zone and highest chitinolytic index. Theanalysis to the base sequence (total 1,322 bp) using 16s rRNAgene sequencing revealed that E76 isolates had 99% similaritywith Burkholderia sp

Control of Anthracnose Disease (Colletotrichum Gloeosporioides) Using Nano Chitosan Hydrolyzed by Chitinase Derived From Burkholderia Cepacia Isolate E76

Anthracnose (Colletotrichum gloeosporioides) is one of the important diseases of fruit crops that need to be controlled. This study was aimed to obtain the best formula of hydrolyzed nano chitosan and its potensial in controlling anthracnose. The hydrolyzed chitosan was prepared using chitinase enzyme extracted from Burkholderia cepacia isolate E76. Chitosan nanoparticles were synthesized using ionic gelation method by reacting hydrolyzed chitosan (0.2%) with Sodium tripolyphosphate (STPP) (0.1%) as cross-linking agent using 30&amp;ndash;60 minutes stirring condition. The bioactivity of the nano chitosan formula was tested to C. gloeosporioides under in vitro and in vivo assays. The specific enzymatic activity of the purified chitinase was higher (0.19 U/mg) than that of crude enzyme (supernatant) with the purity increased by 3.8 times. Of the four formula tested, Formula A (hydrolyzed chitosan to STPP volume ratio of 5 : 1 with 60 minutes stirring condition) was found good in terms of physical characteristic of the particle. The formula nano chitosan particle had the spherical-like shape with an average particle size of 126.2+3.8 nm, polydispersity index (PI) of 0.4+0.02, and zeta potential (ZP) value of 27.8+0.2 mV. Nano chitosan had an inhibitory activity to C. gloeosporioides in vitro up to 85.7%. Moreover, it could inhibit 61.2% of C. gloeosporioides spores germination. It was shown that nano chitosan was also effective to reduce anthracnose disease severity in vivo when applied as a preventive measure on Chili and papaya fruits. This study could be used as a reference for further fruit coating application using nano chitosan as a promising postharvest biocontrol agent to C. gloeosporioides

Keragaman Genetik Rizobakteri Penghasil Asam Indol Asetat Berdasarkan 16S RRNA dan Amplified Ribosomal DNA Restriction Analysis

Asam indol asetat (AIA) dapat dihasilkan oleh bakteri rizosfer/rizobakteri pemacu pertumbuhan tanaman (PPT). Keragaman genetik isolat bakteri PPT indigenous Indonesia perlu diinvestigasi untuk mencari sumber potensial agen PPT dengan informasi kekerabatan intra dan interspesies yang jelas. Karena itu penelitian ini bertujuan mengetahui keragaman genetik rizobakteri penghasil AIA indigenous Indonesia dengan gen 16S rRNA, dilengkapi dengan ARDRA. Koleksi isolat bakteri BB Biogen diidentifikasi kandungan AIA-nya, morfologi secara makroskopis dan sekuensing pada sekuen 16S rRNA dan ARDRA. Total empat belas isolat rizobakteri memiliki kandungan AIA dalam kisaran 5,24-37,69 µg/ml dan tertinggi pada SM1. Karakteristik morfologi koloni rizobakteri mendukung variasi strain bakteri penghasil AIA. Delapan isolat terpilih diidentifikasi sebagai spesies Bacillus dengan homologi 96-99%. Lima isolat (SM1, JP4, KP3, MB2, dan CP3) diidentifikasikan sebagai B. subtilis, SC2 sebagai B. amyloliquefaciens, BL2 dekat dengan B. velezensis, dan JP3 memiliki homologi tinggi dengan Brevundimonas olei. Delapan isolat rizobakteri tersebut berkerabat dekat dengan strain bakteri referensi yang memiliki kesamaan spesies. Analisis ARDRA-RsaI menghasilkan lima filotipe dengan keunikan pola sidik jari. Isolat CP3, MB 2, dan KP 3 berada dalam satu filotipe. Kedekatan isolat dalam Bacillus sp. digambarkan oleh filotipe 5 (B. subtilis SM1 dan B. velezensis BL2) yang diduga jauh dari B. amyloliquefaciens SC2 (filotipe 4) dan JP 3 pada genus Brevundimonas (filotipe 3). Keragaman genetik isolat rizobakteri penghasil AIA terhitung rendah berdasarkan 16S-rRNA dan ARDRA-RsaI

Identifikasi Entomopatogen Bakteri Merah Pada Wereng Batang Coklat (Nilaparvata Lugens Stål.)

Indentification of Entomopathogenic Red Bacterial fromBrown Planthopper (Nilaparvata lugens Stål.). Tri P.Priyatno, Yohana A. Dahliani, Yadi Suryadi, I MadeSamudra, Dwi N. Susilowati, Iman Rusmana, Baskoro S.Wibowo, and Cahyadi Irwan. Red bacteria isolated frombrown planthopper (BPH) has been proven pathogenicagainst BPH and others insects. Application of 106 to 107cells/ml of red bacteria caused 65.6-78.2% mortality of BPH.The 50% effective concentration (EC50) and lethal time of redbacteria against BPH is 2.8 x 105 cells/ml and 6.8 days,respectively. Based on phenotypic characters tested on GNMicroPlateTM Biolog kit and 16S rRNA sequneces analysis,red bacteria was identified as Serratia marcescens with 99%similarity. Red pigmen produced by S. marcescens strainBPH is secondary metabolite determined as prodigiosinshowing bactericidal activities against Xanthomonas oryzaepv. oryzae. We concluded that S. marcescens did not onlypotent as biocontrol agent to BPH, but also it can be used tocontrol plant pathogenic bacteria