Penelitian ini bertujuan untuk mengetahui pengaruh dan dosis yang terbaik pada pemanfaatan diatomae Chaetoceros ceratosporum dalam formula pakan terhadap peningkatan respon imun seluler udang windu (Penaeus monodon Fab.). Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) dengan 4 perlakuan dan 3 ulangan. Sebagai perlakuan adalah pemanfaatan Chaetoceros ceratosporum dalam formula pakan iso protein 39,02% dan iso energy 3,58 kkal g pakan dengan dosis yang berbeda yaitu: A (0%), B (3,04%), C (6,08%) dan D (9,12%). Parameter yang diamati adalah total hemosit, total diferensial hemosit (hyaline, semi granular dan granular), dan aktivitas vibriocidal. Berdasarkan hasil penelitian menunjukkan bahwa pemanfaatan diatomae Chaetoceros ceratosporum dalam formula pakan dapat meningkatkan respon imun seluler, dan dosis terbaik berkisar 5,15%-6,51%.

Water quality and waste management are significant problems for aquaculture in Indonesia, including catfish (Clarias gariepinus) aquaculture. A combination of Aquaponics Systems and Recirculating Aquaculture Systems (A-RAS) has been developed to address this problem. This study analyzed A-RAS application for catfish (Clarias gariepinus) aquaculture by comparing water quality and production indicators between A-RAS and conventional methods. The results show that temperature, pH, dissolved oxygen, total organic matter, ammonia, nitrate and nitrite in A-RAS technology were 28.0-30.0°C, 6.5-7.9, 3.8-7.8 mg/L, 18.54-24.97 mg/L, 0.12- 0.28 mg/L, 0.12-0.13 mg/L, and 0.04-0.13 mg/L, respectively. Survival Rate, Feed Conversion Ratio, and harvest in A-RAS application were 85.5%, 1.1, and 26 kg/m³, respectively. A-RAS technology can maintain water quality to be reused in cultivation and increase yields by about 13%. Besides, water spinach can be an additional income for farmers.

Spirulina platensis is a filamentous cyanobacterium that has been commerically used for fish feed and human food supplement. Low-cost production of Spirulina is needed when considering large-scale culture especially for industrial purposes. The aim of this study was to explain the effect of calcium nitrate (Ca(NO3)2) on growth, biomass, pigment, and protein production of S. platensis and to determine the best calcium nitrate concentration for Spirulina production.The microalgae was cultured at four calcium nitrate concentrations (1, 1.5, 2.0 and 2.5 g/L) with salinity of 15 ppt, constant light intensity of 4,000 lux and photoperiod of 24:0 light:dark cycles for 4 days. The results showed that different calcium nitrate concentrations remarkably affected the growth, biomass production, pigment and protein content of S. platensis (p<0.05). The highest specific growth rate of 0.721 day-1 and biomass concentration of 1.512 g/Lwere achieved at calcium nitrate concentration of 2.5 g/L. Moreover, the algae had the highest chlorophyll-a, carotenoid and protein content at 2.5 g L-1. Increasing calcium nitrate concentration from 1 to 2.5 g/L led to an increase in biomass, pigment and protein production of S. platensis. However, there was no significant difference between 2 and 2.5 g L-1 calcium nitrate concentrations. We suggest that 2-2.5 g/L Ca(NO3)2 concentration can be used profitably for S. platensis production.

The aim of this study was to determine the effect and the best dosage used by the Skeletonema costatum in feed formulation on the growth of Vaname shrimp. This experiment used Completely Randomized Design (CRD) with four treatments and three replications. Treatment was given by using dried S. costatum in feed formula (iso protein 37% and iso energy 3.6 kkal/g feed). Feed treatment was the substitution of fish meal protein A = 0%, B = 2.5%, C = 5% and D = 7.5% with dried S. costatum protein. The observed parameters include Survival Rate (SR), Survival Growth Rate (SGR), Feed Efficiency Ratio (FER), and Protein Efficiency Ratio (PER). The results showed that the use of dried S. costatum in feeding are effective in increasing the specific growth rate, feed efficiency ratio and the ratio of protein efficiency than controls. The best dosage in feeding formula is ranged from 4.39% to 4.75%.

Abstract. Fakhri M, Riyani E, Ekawati AW, Arifin NB, Yuniarti A, Widyawati Y, Saputra IK, Samuel PD, Arif MZ, Hariati AM. 2021. Biomass, pigment production, and nutrient uptake of Chlorella sp. under different photoperiods. Biodiversitas 22: 5344-5349. Chlorella sp. is well-known as a functional feed in fish culture and has been utilized in the food industry. In phototrophic cultivation, photoperiod plays a fundamental part in the growth and pigment content of microalgae. This work was purposed to evaluate the effect of light:dark cycle on the growth rate, production of biomass and pigment and nutrient utilization of Chlorella sp. Four photoperiods (8:16, 12:12, 18:6, and 24:0 h light:dark regimes) under a constant light intensity of 4500 lux were applied in this study. The results demonstrated that increasing light duration led to increased cell growth, biomass, and pigment production of Chlorella sp. The best cell concentration, specific growth rate, and biomass production were 28.5 x 106 cells mL-1, 1.47 day-1, and 0.815 g L-1 dry weight, respectively, under continuous illumination. The maximum chlorophyll a of 19.205 mg L-1 and carotenoid of 4.656 mg L-1 were obtained at 24:0 h photoperiod. The highest uptake of nitrate (66.331%) and phosphate (76.191%) by Chlorella sp. were achieved under 24 h light regime. Improving the uptake of nutrients resulted in enhanced growth and pigment content of Chlorella sp. We conclude that continuous illumination is the best photoperiod to produce biomass and pigment and improve the nutrient removal of Chlorella sp.