Water quality and juvenile development of mullet Mugil liza in a biofloc system with an additional carbon source: Dextrose, liquid molasses or rice bran?

Abstract

This work investigates the effect of adding different sources of organic carbon in biofloc systems on water quality, microorganisms' density and zootechnical performance of juvenile Mugil liza raised in the biofloc system indoors over 45 days. Fish (±7.99 g) were stored at a density of 15 fish per tank and fed a commercial feed of 42% protein.The study was arranged in three treatments according to the carbon source: dextrose-DE, liquid molasses-LM and rice bran-RB, and one control with no bioflocs (clear water-CW), all in triplicate. The treatments had no influence (p > 0.05) on the performance parameters of the animals, survival (over 90%), as well on the productivity (between 0.35 and 0.6 kg/m 3 ). Overall mean of total ammonia was lower (p < 0.05) in the biofloc systems than in clear water (CW). Nitrite average was lower (p < 0.05) in the bioflocs fertilized with LM and RB carbon sources, having a concentration of 1.3 ± 1.9 mg/L and 0.6 ± 0.6 mg/L respectively. RB also had the smallest range in nitrite levels throughout the study, from 0.04 to 2.5 mg/L. The LM and RB provided a greater (p < 0.05) abundance of total adhered and coccus bacteria. Water consumption was higher (p < 0.05) in the CW (1.87 m 3 per tank) compared with the biofloc treatments (0.41 and 0.44 m 3 per tank). Liquid molasses contributed to maintaining water quality compared with clear water, providing savings of around 80% of water.

Modeling Nile Tilapia Heterogeneous Growth under Different Stocking Densities during Pre-Grow-Out Stage

“…Settling solids were determined using Imhoff ® (DWK Life Sciences, Millville, NJ, USA) cones with a settling time of 20 min and taken daily alternating each tank once per treatment at 8:00 hr. An optimal level for juvenile tilapia from 20 to 50 mL L −1 was maintained throughout the culture; when the allowed level exceeded, it was controlled with limited water exchanges (10%) and a sedimentation tank connected to the culture tanks with recirculating water [66][67][68][69][70][71].…”

“…The water exchange rate was 10% every other day from Days 7 to 33 and 30% 1 day a week from Days 55 to 69; water recirculation through the sedimentation tank was 8 hr/day from Days 34 to 69. To ensure that water management was adequate, the volume of flocs was measured before and after these processes [70].…”

Potensi Pengembangan Pangan Ikan Haruan Sebagai Ikan Lokal Kalimantan Tengah melalui Perbaikan Sistem P4t1 di Era Milenial

“…Dengan menerapkan sistem ini, petani dapat memaksimalkan penggunaan lahan dan meningkatkan hasil panen ikan dan tanaman. Selain itu, sistem P4t1 menekankan pada penggunaan teknologi yang ramah lingkungan dan hemat biaya untuk meningkatkan efisiensi dan kualitas produksi p-ISSN: 2828-7665 e-ISSN: 2828-609X __________________________________________________________________________________ 45 ikan (Rocha et al, 2021). Selain potensi keuntungan ekonomi, pengembangan ikan Haruan sebagai sumber pangan lokal juga dapat memberikan dampak positif bagi kesehatan masyarakat.…”