A metagenomic comparison of clearwater, probiotic, and Rapid BFTTM on Pacific whiteleg shrimp, Litopenaeus vannamei cultures.

Biofloc technology improves water quality and promote the growth of beneficial bacteria community in shrimp culture. However, little is known about the bacteria community structure in both water and gut of cultured organisms. To address this, the current study characterised the metagenomes derived from water and shrimp intestine samples of novel Rapid BFTTM with probiotic and clearwater treatments using 16S V4 region and full length 16S sequencing. Bacteria diversity of water and intestine samples of Rapid BFTTM and probiotic treatments were similar. Based on the 16S V4 region, water samples of >20 µm biofloc had the highest abundance of amplicon sequence variant (ASV). However, based on full length 16S, no clear distinction in microbial diversity was observed between water samples and intestine samples. Proteobacteria was the most abundant taxon in all samples based on both 16S V4 and full length 16S sequences. Vibrio was among the highest genus based on 16S V4 region but only full length 16S was able to discern up to species level, with three Vibrios identified-V. harveyi, V. parahaemolyticus and V. vulnificus. Vibrio harveyi being the most abundant species in all treatments. Among water samples, biofloc water samples had the lowest abundance of all three Vibrios, with V. vulnificus was present only in bioflocs of <20 µm. Predicted functional profiles of treatments support the beneficial impacts of probiotic and biofloc inclusion into shrimp culture system. This study highlights the potential displacement of opportunistic pathogens by the usage of biofloc technology (Rapid BFTTM) in shrimp culture.

Assessment on Water Quality Parameter and Nutrients Level of Nyatuh River in Relations with Macrobrachium Rosenbergii Prawn Populations.

In order to determine the safety level of water parameters and nutrients in the natural environment of fish and freshwater prawn in Nyatuh River, Terengganu, Malaysia, it is necessary to conduct an assessment of water quality parameters. Due to its important, a study was conducted to assess the water quality parameter and nutrients contents from Nyatuh River of Setiu Terengganu in relations to the population of freshwater prawn, Macrobrachium rosenbergii caught along the Nyatuh River basin. Total of four expeditions and five stations at different tidal condition for the water quality parameter were assessed during the study. From the results achieved, the overall temperature varied between (26.56°C-29.30°C), dissolved oxygen, DO (3.59 mg/L-6.50 mg/L), pH (4.99-7.01), salinity (0.01ppt-4.22ppt), depth (2.71 m-5.54 m) while for ammonia (0.01 mg/L-0.24 mg/L), nitrite (0.01 mg/L-0.05 mg/L) and phosphate (0.01 mg/L-0.12 mg/L). While the number of prawns caught are 176, 160, 102 and 68 for Expeditions 1, 2, 4 and 3, respectively. Possibly, the heterogeneous number of prawns caught is a result of significant differences in water level depth during high tides and low tides, as well as a fluctuation in the ammonia concentration levels in each of the stations and expeditions. For statistical analysis, the temperature showed no significant difference between the expedition, stations and tidal. That is p = 0.280, p > 0.05 and F = 1.206, respectively. While dissolved oxygen, DO, showed no significant difference as well, that is p = 0.714, p > 0.05 and F = 0.737. However, the level of water depth was significantly different between expedition, station and tidal, that is p = 0.000, p < 0.05 and F = 3.120. Ammonia, on the other hand shows no significant difference between expedition, station and tidal, that is p = 0.476, p > 0.05 and F = 0.973. The same goes for nitrite and phosphate concentration. There was no significant difference between expedition, stations and tidal, that is p = 0.569, p > 0.05 and F = 0.879 and p = 0.247, p > 0.05, F = 1.255, respectively. In Expedition 1, the good water quality parameter and very low ammonia concentration resulted in a larger prawn population as compared to other expeditions. The distribution or mixture of prawns caught is heterogeneous at different stations due to the significant differences in water depth and also to the fluctuation in water quality due to varying ammonia levels. In conclusion, the water quality in Nyatuh River fluctuated across expeditions, stations, and tides, as well as significant differences in water level depths between high and low tides. Due to the rapid growth and importance of industrial and aquaculture operations along the river, extra attention should be devoted to avoid the impact of excessive pollutant in order to protect the ecosystem.

Penilaian parameter kualiti air perlu dijalankan untuk menentukan tahap keselamatan parameter air dan nutrien dalam persekitaran semula jadi ikan dan udang air tawar di Sungai Nyatuh, Terengganu, Malaysia. Maka, satu kajian telah dijalankan untuk menilai parameter kualiti air dan kandungan nutrien di Sungai Nyatuh, Setiu, Terengganu dalam hubungan dengan populasi udang air tawar, Macrobrachium rosenbergii yang ditangkap di sepanjang lembangan Sungai Nyatuh. Sebanyak empat ekspedisi dan lima stesen pada keadaan pasang surut berbeza untuk parameter kualiti air telah dinilai semasa kajian dijalankan. Berdasarkan keputusan yang dicapai, suhu keseluruhan berbeza-beza antara (26.56°C­29.30°C), oksigen terlarut (3.59 mg/L­6.50 mg/L), pH (4.99­7.01), kadar kemasinan (0.01ppt­4.22ppt), kedalaman (2.71 m­5.54 m) sementara bagi ammonia (0.01 mg/L­0.24 mg/L), nitrit (0.01 mg/L­0.05 mg/L) dan fosfat (0.01 mg/L­0.12 mg/L). Manakala bilangan udang yang ditangkap adalah 176, 160, 102 and 68 ekor, masing-masing untuk Ekspedisi 1, 2, 4 dan 3. Bilangan heterogen udang yang ditangkap berkemungkinan adalah hasil daripada perbezaan ketara dalam kedalaman paras air semasa air pasang dan air surut, serta turun naik paras kepekatan ammonia di setiap stesen dan ekspedisi. Bagi analisis statistik, suhu tidak menunjukkan perbezaan yang signifikan antara ekspedisi, stesen dan pasang surut, iaitu p = 0.280, p > 0.05 dan F = 1.206, masing-masing. Oksigen terlarut juga tidak menunjukkan perbezaan yang signifikan, iaitu p = 0.714, p > 0.05 dan F = 0.737. Walau bagaimanapun, paras kedalaman air adalah berbeza secara signifikan antara ekspedisi, stesen dan pasang surut, iaitu p = 0.000, p < 0.05 dan F = 3.120. Ammonia pula tidak menunjukkan perbezaan yang signifikan antara ekspedisi, stesen dan pasang surut, iaitu p = 0.476, p > 0.05 dan F = 0.973. Begitu juga dengan kepekatan nitrit dan fosfat. Tidak terdapat perbezaan yang signifikan di antara ekspedisi, stesen dan pasang surut, iaitu masing-masing pada p = 0.569, p > 0.05 dan F = 0.879 dan p = 0.247, p > 0.05, F = 1.255. Dalam Ekspedisi 1, parameter kualiti air yang baik dan kepekatan ammonia yang sangat rendah menghasilkan populasi udang yang lebih besar berbanding ekspedisi lain. Taburan atau campuran udang yang ditangkap adalah heterogen di stesen yang berbeza disebabkan oleh perbezaan ketara dalam kedalaman air dan juga turun naik kualiti air akibat paras ammonia yang berbeza-beza. Kesimpulannya, kualiti air di Sungai Nyatuh berubah-ubah merentasi ekspedisi, stesen dan pasang surut, serta perbezaan ketara dalam kedalaman paras air antara air pasang tinggi dan rendah. Disebabkan pertumbuhan pesat dan kepentingan operasi perindustrian dan akuakultur di sepanjang sungai, perhatian tambahan harus ditumpukan untuk mengelakkan kesan pencemar yang berlebihan untuk melindungi ekosistem.