Nitrogen and Phosphorus budget for Nile tilapia hatchery

Abstract

Tilapia hatcheries if not well managed, it can cause environmental damage. The present study was designed to quantify the impacts generated by Nile tilapia hatcheries, through applying environmental indicators, which is necessary for tilapia hatcheries sustainable development. Three culture trials, each of 15 days, have been carried out to determine environmental indicators: the nitrogen and phosphorus flux and nutrient mass balance based on inputs from feed and losses in fish harvest, nutrients load in the effluent water, and fish bio-solid wastes (sludge). In each, three cement ponds were assigned to determine the nutrients input and loss for 15 days intervals, fry production cycle. The results showed that every 1 Kg feed of 35% protein produce 420 g sludge, of which 262 gm fish excretion. Uneaten feed was found to represent 15.8-20% of the introduced feed and produce 37.6 -43.2 % of sludge. Fish retained at least 25.8 ± 3.91 % and 2.74 ± 0.37 % of the input feed nitrogen and phosphorus, respectively. While the sludge contained 11.3 ± 0.78 % and 32.62 ± 14.46 of the feed nitrogen and phosphorus, respectively. Effluent water contained 43.64 ± 6.45 % and 50.22 ± 16.63 % of feed nitrogen and phosphorus, respectively, distributed in three main fractions: particulate form; dissolved organic and dissolved inorganic forms. The feed nitrogen recovery in the present study was 80. 57%, while the phosphorus recovery reached 85.58% of the feed phosphorus content. Fry production is discussed in response to the feed protein content and feeding rate.

Effect of supplementary lighting on nutrient recovery of Ocimum basilicum and fishes in a polyculture aquaponic system

“…These reports show that O. basilicum in the present study has a higher NPK recovery than the reported plants. A study by Moustafa et al (2020), which reported 25.8% N and 2.74% P recovery in a RAS with Nile tilapia, was lower compared to the observations of this study for fish (30.81%-31.2% N; 44.58%-48.3% P) and crayfish (18.96%-20.48% N; 9.32%-10.25% P). The differences in nutrient recoveries may be linked to the different culture systems used in both studies.…”

Study of Nitrogen and Phosphorus transformations in cement ponds of Nile tilapia fry.

“…To achieve such responsible systems, it is necessary to fully understand the nature of the pollutant nutrients and their transformation clearly. Several studies have documented the nutrients budget in several fish species production systems (Moustafa et al, 2020). Nevertheless, there is a serious dearth of literature focusing on the nutrients budget in the fry rearing ponds in the hatcheries.…”