Due to the mainly imported for fish feed ingredients in Indonesia, many attemps have been made to discover local potential ingredients to reduce the utilization of imported ingredients. In this experiment, the utilization of Ulva lactuca as feed ingredient for tilapia was evaluated. Experiment 1 was conducted to determine the digestibility of Ulva for tilapia. In experiment 2 and 3, Ulva was used to substitute wheat pollard of either 0, 3, 6, 9, or 12 % in the feed formulation. In experiment 2, fish with an average body weight of 4.1±0.15 g were fed on those diets, and were cultured for 55 days. To calculate the digestibity in experiment 3, Cr 2 O 3 was added into the diet of exeriment 2; then fed on the fish with an average body weight of 19.0±0.67 g. Results showed that apparent digestibility of dry matter and crude protein of Ulva were 66.3 and 83 %, respectively. Ash content in the diet increased of 13.5% with Ulva inclusion of 12%. On the other hand, using Ulva as a substitute for pollard up to 12% was not affected the growth performance of fish. Regardless of the Ulva level in the diet, the digestibility of the diet was the same. Therefore, Ulva is a potential source of local feed ingredient for tilapia. ABSTRAKUntuk mengurangi ketergantungan bahan baku pakan impor, telah dilakukan penelitian untuk mengetahui potensi rumput laut Ulva lactuca sebagai bahan baku pakan ikan nila. Penelitian tahap 1 adalah mengevaluasi kecernaan Ulva di ikan nila. Di dalam penelitian tahap 2 dan 3, Ulva ditambahkan ke dalam formulasi sebanyak 0, 3, 6, 9, dan 12 % untuk mengganti pollard. Di penelitian 2, pakan diberikan ke ikan nila ukuran 4,1±0,15 g selama 55 hari, lalu diukur kinerja pertumbuhannya. Sedangkan di penelitian 3, pakan penelitian 2 ditambah Cr 2 O 3 , lalu diberikan ke ikan ukuran 19,0±0,67 g untuk uji kecernaan pakan. Hasil penelitian menunjukkan bahwa Ulva memiliki kecernaan total dan protein yang tinggi, masing-masing 66,3 dan 83,0 %. Peningkatan jumlah Ulva di dalam formulasi pakan meningkatkan kadar abu pakan, sehingga pada penambahan Ulva 12 %, kadar abu pakan mencapai 13,5 %. Namun demikian, penggunaan Ulva sebagai pengganti pollard sampai 12 % tidak menurunkan kinerja pertumbuhan ikan nila. Penggunaan Ulva sebagai bahan baku pakan ikan nila juga tidak menurunkan kecernaan pakan tersebut. Oleh karena itu bisa disimpulkan bahwa Ulva sangat potensial untuk digunakan sebagai bahan baku pakan ikan nila.Kata kunci: Ulva lactuca, ikan nila, kecernaan, pertumbuhan

ABSTRACT Cultivation of Panulirus homarus lobster is now carried out with sub-mersible net cage system at a certain depth in order to obtain optimal temperature, light and water pressure. The purpose of this study was to evaluate the health status of the sand lobster P. homarus which was kept in sub-mersible net cage system measuring 250 cm × 272 cm × 135 cm with a depth of 6 m and 8 m in the waters of Semak Daun Island, Seribu Islands, DKI Jakarta. The average size of lobster seeds used was 93.23 ± 0.99 g/head with a density of 4 lobsters/m2. Lobsters were fed trash fish, molluscs and crustaceans, with a frequency of twice a day at 07.00 WIB 30% and 17.00 WIB 70% of the lobster biomass weight. This study used a completely randomized design with the two depth treatments mentioned above and three replications. Observations of total haemocyte count, differential haemocyte count, phenoloxidase activity, respiratory burst phagocytic activity and histology of lobster hepatopancreas were performed twice every 14 days. Based on the above observations, the depth does not affect the immune response, there is no visible damage to the cells and tissues of the lobster hepatopancreas. Keywords: haemolymph, histology, lobster cultivation, sea, sub-mersible net cage system

No abstract

A triplicate experiment was conducted to evaluate the effect of glutamine supplementation in the diet on the structure and function of intestine and the growth performance of striped catfish Pangasius hypopthalmus. Forty fishes with an initial body weight of 0.82 ± 0.01 g were distributed into a rectangular aquarium with a size of 60×50×40 cm and a water volume of 70 L. Fish were fed on the diet supplemented with glutamine of either 0, 1, 2, or 3%, respectively. Fish were fed on the diet at satiation for 60 days. Results showed that fish fed on the diet supplemented with 1, and 2% of glutamine significantly had the highest growth performance, including specific growth rate, protein retention, and feed efficiency. On the other hand, feeding on a diet supplemented with 3% of glutamine did not significantly affect the growth performance of fish. Fish in 1% and 2% glutamine treatments had better structure and function of intestine than two other groups of fish, namely the ratio of intestine length with body length, villus surface area, and protease enzyme activity. Thus, supplementation of 1% and 2% glutamine in the diet improves the structure and function of intestine and the growth performance of striped catfish. Abstrak Percobaan dilakukan untuk mengevaluasi pengaruh penambahan glutamin pada pakan terhadap struktur dan fungsi usus, serta kinerja pertumbuhan ikan patin Pangasius hypopthalmus. Ikan uji yang digunakan sebanyak 40 ekor dengan bobot awal 0,82 ± 0,01 g dipelihara dalam akuarium berukuran 60 × 50 × 40 cm dan volume air 70 L. Ikan diberi pakan uji dengan penambahan glutamin 0, 1, 2, dan 3%. Ikan diberi pakan uji secara at satiation selama 60 hari. Hasil penelitian menunjukkan bahwa ikan yang diberi pakan dengan penambahan glutamin 1% dan 2% secara signifikan menghasilkan kinerja pertumbuhan tertinggi, termasuk laju pertumbuhan spesifik, retensi protein, dan efisiensi pakan. Di sisi lain, pakan yang ditambah dengan glutamin 3% tidak signifikan memengaruhi kinerja pertumbuhan ikan. Ikan uji pada perlakuan glutamin 1% dan 2% menghasilkan struktur dan fungsi usus yang lebih baik dibanding perlakuan lainnya, yakni rasio panjang usus dengan panjang tubuh, luas permukaan vili dan aktivitas enzim protease. Disimpulkan bahwa penambahan glutamin 1% dan 2% pada pakan meningkatkan struktur dan fungsi usus serta kinerja pertumbuhan benih ikan patin.

In marine aquaculture, immersing marine fish species in fresh water can remove ectoparasite that adhere to all over the fish body. This study aimed to evaluate the impacts of combining microbial floc and microalgae Spirulina platensis in juvenile cobia diet on growth performance and stress responses after immersion in aerated fresh water for 15 minutes. The fishes were reared in concrete tanks for 40 days before collecting data on their growth performance. The stress response was determined by measuring both glucose and cortisol levels before (0 h) and after (1, 2, 4, 6, 24 hours) immersion. The fishes fed on the 15% of combining microbial flock and microalgae Spirulina platensis diet showed the highest growth rate with the lowest feed conversion ratio compared to other treatments. The cortisol level of juvenile cobia in both the 15% and 30% combination of microbial floc and microalgae Spirulina platensis treatments did not increase during the first hour following the immersion compared to the control treatment. The glucose level also increased after one hour immersion in freshwater of all treatments. This indicated that feeding juvenile cobia on microbial flocs and microalgae diets had a retarding effect on the physiological responses (cortisol and glucose) after immersion in fresh water. ABSTRAKPenelitian ini bertujuan untuk mengevaluasi kombinasi mikrobial flok dan mikroalga Spirulina platensis dalam pakan juvenil cobia terhadap kinerja pertumbuhan dan respons stress setelah direndam air tawar selama 15 menit dengan aerasi. Ikan dipelihara dalam bak beton selama 40 hari kemudian diambil data kinerja pertumbuhannya. Setelah diaklimatisasi selama seminggu, ikan direndam dalam air tawar. Data respons fisiologis melalui pengukuran kadar glukosa dan kortisol. Sebelum diberi perlakuan (0 jam) dan setelah 1, 2, 4, 6, 24 jam. Ikan yang diberikan pakan kombinasi mikrobial flok dan mikroalga Spirulina platensis sebesar 15% menunjukkan pertumbuhan yang lebih cepat dengan konversi pakan yang lebih rendah dibanding kontrol dan perlakuan lainnya. Hasil pengukuran terhadap kadar kortisol setelah 1 jam, diperoleh bahwa ikan yang diberikan pakan kombinasi mikrobial flok dan mikroalga Spirulina platensis 15% dan 30% tidak mengalami peningkatan kortisol yang berbeda dengan kontrol. Kadar glukosa mengalami kecenderungan meningkat mulai dari jam ke-1 dan tertinggi pada jam ke-2 kemudian kembali menurun pada jam ke-4 hingga terjadi keseimbangan fisiologis di jam ke-6 pada semua perlakuan. Dengan demikian ikan yang diberikan pakan kombinasi mikrobial flok dan mikroalga Spirulina platensis 15% dan 30% dapat mengurangi dampak negatif (stress) setelah direndam dalam air tawar.