Evaluation of health status and meat quality of dumbo catfish Clarias gariepinus maintained using the biofloc system

This research aimed to evaluate the health status, growth performance, and meat quality of African catfish Clariasgariepinus maintained in biofloc and nonbiofloc systems. This study applied 3 treatments with 4 replications, i.e.K500 (control, a non-biofloc system at a fish stocking density of 500/m3), BF500 (biofloc system at a fish stockingdensity of 500/m3), and BF700 (biofloc system at a fish stocking density of 700 /m3). The initial body length andbodyweight of the fish used in this experiment were 10–12 cm and 10–12g, respectively. Feeding was done byusing a commercial feed containing 29.76% protein content. The results showed that fish survival in treatmentsBF500 and BF700 were significantly different (P<0.05) from the control. The growth rate of African catfish in thecontrol (K) was the lowest (3.64 ± 0.56%) among the treatments. The results of the organosensory test showed thatthe application of biofloc systems produced a higher quality of fish meat with a range value of 7–9 compared to thatof the control with a range of 6–7. In conclusion, the application of biofloc systems could improve the fish healthstatus, growth performance, and meat quality of African catfish. Keywords: biofloc systems, Clarias gariepinus, density, health status, meat quality ABSTRAK Penelitian ini bertujuan mengevaluasi status kesehatan, kinerja pertumbuhan, dan kualitas daging ikan lele AfrikaClarias gariepinus yang dipelihara menggunakan sistem bioflok dan nonbioflok. Penelitian ini menggunakan 3perlakuan dengan 4 kali ulangan, yang terdiri dari: K500 (kontrol, sistem nonbioflok dengan kepadatan ikan 500ekor/m3), perlakuan BF500 (sistem bioflok dengan kepadatan ikan 500 ekor/m3), dan perlakuan BF700 (sistembioflok dengan kepadatan ikan 700 ekor/m3). Ikan yang digunakan berukuran panjang dan bobot awal masingmasing10–12 cm dan 10–12 g. Pemberian pakan dilakukan dengan menggunakan pakan komersil dengan 29,76%protein. Hasil penelitian menunjukan tingkat kelangsungan hidup antara perlakuan BF500 dan BF700 berbeda nyata(P<0.05) dengan perlakuan K500. Laju pertumbuhan ikan lele pada perlakuan K500 lebih rendah dibandingkanperlakuan lain. Hasil pengujian organosensory menunjukkan bahwa ikan yang dipelihara dalam sistem bioflokmenghasilkan kualitas daging yang lebih tinggi dengan kisaran nilai 7–9 dibandingkan dengan ikan K500 dengannilai 6–7. Berdasarkan hasil penelitian ini dapat disimpulkan bahwa aplikasi sistem bioflok dapat meningkatkanstatus kesehatan, laju pertumbuhan, dan kualitas daging ikan lele Afrika. Kata kunci: bioflok, Clarias gariepinus, kepadatan, kualitas daging, status kesehatan

Nitrogen budget in recirculating aquaponic systems with different fish stocking density

As in any agroecosystem, also in aquaponics the nitrogen (N) balance represents an important tool to evaluate sustainability, and to identify factors that can improve N use efficiency (NUE) and reduce N losses. In this respect, fish stocking density has been little investigated, hence this research aimed to evaluate the N balance of a low technology aquaponic (AP) system managed at two fish densities in comparison with a hydroponic system (HP). In the fish tanks common carp at two initial stocking densities were reared (2.5 and 4.6 kg m–3 in low and high AP, hereafter named APL and APH, respectively) and the vegetated sector was cultivated with a leafy vegetable crop succession (Catalogna chicory, lettuce, Swiss chard). The N balance considered N input as fish feed or fertiliser, and N content in the initial water and the N output as N in the incremented fish biomass, in the harvested vegetables, in the sediments, and in the remaining water. Total N loss was estimated by difference. The total N input and the N loss through gas emission in the atmosphere were much higher in AP than in HP, particularly at high stocking density. The opposite trend was observed for the N input recovered in vegetable aboveground biomass. The N input recovered as fish biomass was slightly higher in APL compared to APH. The better results of APL than APH suggest that in low-tech AP system lower initial fish density should be adopted at the system start up to maximise both production and N recovery.