scholarly journals Evaluation of resistance against Streptococcus agalactiae in four farmed strains of Nile tilapia (Oreochromis niloticus)

2020 ◽  
Vol 41 (1) ◽  
pp. 351
Author(s):  
Gláucia Frasnelli Mian ◽  
Charles Oswaldo Roncancio ◽  
Maria Cristina de Souza Silva ◽  
Amanda Carvalho Rosado Ferreira ◽  
Dircéia Aparecida da Costa Custódio ◽  
...  
Keyword(s):  
Fish Species ◽  
Streptococcus Agalactiae ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Survival Rates ◽  
Brain Heart Infusion ◽  
Resistance Test ◽  
Economic Losses ◽  
Control Group ◽  
Nile Tilapia Oreochromis Niloticus

Nile tilapia (Oreochromis niloticus) has always been considered more resistant to diseases compared to other fish species. However, in recent decades, this fish species has also been susceptible to many bacterial, fungal, parasitic, and nutritional diseases. In Brazil, streptococcosis is one of the main diseases that affect tilapia and has caused many economic losses. A resistance test was conducted with 93 tilapia of four varieties (UFLA strain and three commercial varieties: SC1, SC2, and SC3) to evaluate resistance to experimental inoculation with Streptococcus agalactiae. Each variety was distributed in five aquariums, with nine specimens of the same variety. Among the five aquariums, four housed fish were intraperitoneally inoculated with 107 CFU/fish of S. agalactiae and one aquarium harbored fish from the control group, which received 0.1 mL of sterile BHI (Brain Heart Infusion). Significant differences were observed in the survival rates accumulated at the end of the experiment (day 15), with values of 22, 36, 36, and 15% for SC1, SC2, SC3, and UFLA, respectively. The UFLA strain presented lower survival than other strains, which did not differ among the 15 days of challenge. These results demonstrate that there are animals with a better response to the resistance test than others.

Nonlethal sampling methods for diagnosis of Streptococcus agalactiae infection in Nile tilapia, Oreochromis niloticus (L.)

Aquaculture ◽  
2016 ◽  
Vol 454 ◽  
pp. 237-242 ◽  
Author(s):  
Guilherme Campos Tavares ◽  
Frederico Augusto de Alcântara Costa ◽  
Raquel Ribeiro Dias Santos ◽  
Gustavo Morais Barony ◽  
Carlos Augusto Gomes Leal ◽  
...  
Keyword(s):  
Streptococcus Agalactiae ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Sampling Methods ◽  
Nile Tilapia Oreochromis Niloticus

scholarly journals Dietary Agaricus blazei Spent Substrate Improves Disease Resistance of Nile Tilapia (Oreochromis niloticus) against Streptococcus agalactiae In Vivo

2022 ◽  
Vol 10 (1) ◽  
pp. 100
Author(s):  
Po-Tsang Lee ◽  
Yu-Sheng Wu ◽  
Chung-Chih Tseng ◽  
Jia-Yu Lu ◽  
Meng-Chou Lee
Keyword(s):  
Cell Line ◽  
Streptococcus Agalactiae ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Water Extract ◽  
Feed Additive ◽  
Agaricus Blazei ◽  
Bacterial Challenge ◽  
Spent Mushroom Substrate ◽  
Nile Tilapia Oreochromis Niloticus

This study evaluated the effects of the feeding of spent mushroom substrate from Agaricus blazei on Nile tilapia (Oreochromis niloticus). The safety of 0–1000 μg/mL A. blazei spent substrate water extract (ABSSE) was demonstrated in the primary hepatic and splenic macrophages and the THK cell line (a cell line with characteristics of melanomacrophages) using a cytotoxicity assay. Here, 10 μg/mL of crude ABSSE promoted the phagocytic activity of macrophages and THK cells. Stimulating ABSSE-primed THK cells with lipopolysaccharides or peptidoglycan resulted in higher expression levels of four cytokine genes (e.g., interleukinz (IL)-1β, IL-12b, IL-8 and tumor necrosis factor α (TNFα)) and one cytokine gene (TNFα), respectively. An in vitro bacterial growth inhibition assay demonstrated that ABSSE could inhibit the growth of Streptococcus agalactiae. In the first feeding trial, Nile tilapia were fed with experimental feed containing 0, 1, or 5% of A. blazei spent substrate (ABSS) for seven and fourteen days followed by bacterial challenge assay. The best result was obtained when Nile tilapia were continuously fed for seven days on a diet containing 1% ABSS, with the survival rate being higher than in groups with 0% and 5% ABSS after challenge with S. agalactiae. In the second trial, fish were fed diets supplemented with 0% or 1% ABSS for seven days, and then all the groups were given the control feed for several days prior to bacterial challenge in order to investigate the duration of the protective effect provided by ABSS. The results showed that the protective effects were sustained at day 7 after the feed was switched. Overall, spent mushroom substrate from A. blazei is a cost-effective feed additive for Nile tilapia that protects fish from S. agalactiae infection.

scholarly journals DINAMIKA POPULASI IKAN NILA (Oreochromis niloticus Linnaeus, 1758) DI DANAU PANIAI, PAPUA

2018 ◽  
Vol 23 (3) ◽  
pp. 193
Author(s):  
Samuel Samuel ◽  
Yoga Candra Ditya ◽  
Vipen Adiansyah
Keyword(s):  
Fish Species ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Lake Management ◽  
Nile Tilapia Oreochromis Niloticus ◽  
Average Maximum ◽  
Fish Samples ◽  
Information Research ◽  
Endemic Fish ◽  
Average Size

Introduksi ikan nila atau “serapia” (Oreochromis niloticus) di Danau Paniai bertujuan untuk meningkatkan diversitas hasil tangkapan dan mengurangi tekanan eksploitasi terhadap jenis ikan endemik. Pertumbuhan dan produksi ikan nila yang cepat tanpa diiringi upaya pengelolaan akan mengancam keberlanjutan ikan endemik di danau. Upaya pengelolaan sumberdaya ikan di suatu perairan membutuhkan informasi dinamika populasi. Penelitian dinamika dan pengelolaan populasi ikan nila dilakukan pada bulan Februari sampai Oktober 2016. Contoh ikan dikumpulkan dari hasil tangkapan nelayan dengan menggunakan jaring insang dengan berbagai ukuran mata jaring dan dari 4 (empat) enumerator pada tujuh stasiun pengamatan. Hasil penelitian menunjukkan populasi ikan nila di Danau Paniai didominasi ukuran panjang individu antara 15-25 cm sebanyak 67,24%. Pola pertumbuhan ikan jantan dan betina adalah isometrik, panjang maksimum rata-rata (L) adalah 37,28 cm dan koefisien pertumbuhan (K) adalah 0,50 per tahun. Mortalitas alami (M) dan mortalitas penangkapan (F) masing-masing sebesar 0,99 dan 0,54 per tahun. Tingkat eksploitasi (E) diperoleh nilai 0,35 lebih kecil dari nilai optimum (E=0,5). Ukuran rata-rata ikan nila tertangkap (Lc) adalah 20,55 cm lebih besar dari ukuran pertama matang gonad (Lm) sebesar 14,73 cm. Nilai Lc>Lm mengindikasikan sebagian besar populasi ikan nila di Danau Paniai sempat melakukan pemijahan sehingga pemanfaatan lebih atau sama dengan nilai optimum diharapkan dapat meningkatkan pemanfataan ikan nila di Danau Paniai. Introduction of nile tilapia (Oreochromis niloticus) in Lake Paniai known as “serapia” is aimed for improving the diversity of catches and reducing the exploitation pressure on the endemic fish species. The rapid growth, reproduction and production of nile tilapia without its management efforts is a new threat to the sustainability of the existence and utilization of endemic fish species in the lake. Management efforts of fish resources require population dynamics information. Research on the dynamics and management of nile tilapia populations was conducted from February to October 2016. Fish samples were collected from fishermen catches using nets with various mesh sizes and from four enumerators at seven observation stations. The results showed that the population of nile tilapia in Lake Paniai was dominated by individual length between 15-25 cm with frequency of 67,24%. The growth pattern of male and female fish were isometric, the average maximum length (L) was 37.28 cm and the growth coefficient (K) was 0.50 per year. Natural mortality (M) and fishing mortality (F) were 0.99 and 0.54 per year respectively. Exploitation rate (E) of 0.35 was smaller than the optimum value (E=0.5). The average size of nile tilapia captured (Lc) was 20.55 cm larger than the first size of gonad maturity (Lm) of 14.73 cm. The Lc value was higher than that the Lm value(Lc>Lm) indicating that most of nile tilapia population in Lake Paniai has spawned so that increasing the more or equal to the optimum value was expected to improve the of nile tilapia fish in Lake Paniai.

scholarly journals Complete Genome Sequences of Three Streptococcus agalactiae Serotype Ia Isolates Obtained from Disease Outbreaks in Nile Tilapia (Oreochromis niloticus)

2018 ◽  
Vol 6 (1) ◽  
Author(s):  
Anita Jaglarz ◽  
Artur Gurgul ◽  
William J. Leigh ◽  
Janina Z. Costa ◽  
Kim D. Thompson
Keyword(s):  
United States ◽  
Streptococcus Agalactiae ◽  
Oreochromis Niloticus ◽  
Nile Tilapia ◽  
Disease Outbreaks ◽  
The United States ◽  
The Other ◽  
Whole Genome ◽  
Genome Sequences ◽  
Nile Tilapia Oreochromis Niloticus

ABSTRACT This paper describes the whole-genome sequences for three Streptococcus agalactiae serotype Ia isolates. The isolates were recovered from the brains of clinically sick tilapia, Oreochromis niloticus, that were suffering from streptococcosis. One isolate was from tilapia in the United States and the other two from fish in China.

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