Julie Ekasari

Immune response and disease resistance of shrimp fed biofloc grown on different carbon sources

The objective of this study was to document the immunological effects of growing shrimp in biofloc systems. The experiment consisted of four types of biofloc systems in which bioflocs were produced by daily supplementation of four different carbon sources, i.e. molasses, tapioca, tapioca-by-product, and rice bran, at an estimated C/N ratio of 15 and a control system without any organic carbon addition. Each biofloc system was stocked with Pacific white shrimp (Litopenaeus vannamei) juveniles that were reared for 49 days. The use of tapioca-by-product resulted in a higher survival (93%) of the shrimp as compared to the other carbon sources and the control. The highest yield and protein assimilation was observed when tapioca was used as the carbon source. After 49 days, phenoloxidase (PO) activity of the shrimp grown in all biofloc systems was higher than that of the shrimp from the control system. Following a challenge test by injection with infectious myonecrosis virus (IMNV), the levels of PO and respiratory burst (RB) activity in the shrimp of all biofloc treatments were higher than that of the challenged shrimp from the control treatment. An increased immunity was also suggested by the survival of the challenged shrimp from the experimental biofloc groups that was significantly higher as compared to the challenged shrimp from the control treatment, regardless of the organic carbon source used to grow the bioflocs. Overall, this study demonstrated that the application of biofloc technology may contribute to the robustness of cultured shrimp by immunostimulation and that this effect is independent of the type of carbon source used to grow the flocs.

Biofloc technology application in aquaculture to support sustainable development goals

Biofloc technology (BFT) application offers benefits in improving aquaculture production that could contribute to the achievement of sustainable development goals. This technology could result in higher productivity with less impact to the environment. Furthermore, biofloc systems may be developed and performed in integration with other food production, thus promoting productive integrated systems, aiming at producing more food and feed from the same area of land with fewer input. The biofloc technology is still in its infant stage. A lot more research is needed to optimise the system (in relation to operational parameters) e.g. in relation to nutrient recycling, MAMP production, immunological effects. In addition research findings will need to be communicated to farmers as the implementation of biofloc technology will require upgrading their skills.

Protein and Energy:Protein Ratio in Diets for Juvenile Bluefin Trevally Caranx melampygus

A 40-day feeding trial assessed the dietary protein and energy:protein ratio requirements for optimum growth performance of juvenile bluefin trevally, Caranx melampygus. Practical diets were formulated to contain 33%, 37%, 41%, or 45% crude protein and either 9 or 11 kcal GE/g. Dietary protein level at any given energy:protein levels significantly affected muscle protein, feed consumption, growth, feed efficiency, survival, and protein and lipid retention. At dietary protein levels >33%, increasing energy:protein ratio to 11 kcal GE/g protein significantly reduced growth performance and feed consumption. Results suggest that optimum growth and feeding response of juvenile bluefin trevally can be attained at a dietary protein level of 45% with an energy:protein ratio of 9 kcal GE/g protein.

Fermentation of Azolla sp. leaves and the utilization as a feed ingredient of tilapia Oreochromis sp.

ABSTRACT The objective of this study was to study the effect of incubation period on the nutritional content of Azolla sp. meal fermented by Trichoderma harzianum, and its optimum supplementation level in the feed of tilapia Oreochromis sp. In incubation period treatments, fermentation of Azolla meal was performed in two, six, eight, and ten days (AF2, AF6, AF8, AF10) using Trichoderma harzianum as the fermentor. The fish used in this study was tilapia Oreochromis sp. with an average weight of 10.59±1.29 g. The design of the feeding treatments was repeletting commercial feed with Azolla leaves by with different supplementation levels, i.e. 0% (A/control), 30% (B), 60% (C), and 90% (D). Faecal collection for digestibility measurement was conducted for 15 days and fish growth rate was observed for 40 days. Azolla meal fermented for two days (AF2) showed the best results among the other treatments with a crude fiber decrease of 37.19% and protein increase of 38.65%. The results of this study indicate that fermentation can increase the nutritional quality of Azolla meal and its most optimal supplementation level in the diet of tilapia is 30%. Keywords: crude fiber, Azolla sp., tilapia ABSTRAK Penelitian ini bertujuan untuk mengetahui pengaruh lama waktu fermentasi daun mata lele Azolla sp. menggunakan kapang Trichoderma harzianum serta dosis optimal dalam pakan ikan nila Oreochromis sp. Proses fermentasi tepung daun mata lele dilakukan selama dua, enam, delapan, dan sepuluh hari (AF2, AF6, AF8, AF10). Ikan uji pada penelitian ini menggunakan ikan nila Oreochromis sp. dengan bobot rata-rata 10,59±1,29 g yang ditebar sebanyak 6 ekor/akuarium berukuran 50×45×30 cm3. Sebagai pakan perlakuan yakni repeletting daun mata lele dengan pakan komersil pada tingkat suplementasi 0% (A/kontrol), 30% (B), 60% (C), dan 90% (D). Pemeliharaan ikan uji dan pengumpulan data dilakukan dengan mengumpulkan feses ikan untuk uji ketercernaan selama 15 hari dan mengamati pertumbuhan ikan selama 40 hari. Tepung daun mata lele yang difermentasi selama dua hari (AF2) memiliki hasil yang paling baik di antara perlakuan lainnya yakni dengan penurunan serat kasar sebesar 37,19% dan peningkatan protein sebesar 38,65%. Hasil penelitian ini menunjukkan bahwa fermentasi dapat meningkatkan kualitas nutrisi daun mata lele serta dosis optimal pemanfaatan tepung daun mata lele fermentasi dalam pakan ikan nila adalah sebesar 30%. Kata kunci: serat kasar, Azolla sp., ikan nila