Use of two freshwater macrophytes, water hyacinth ( Eichhornia crassipes ) and coontail ( Ceratophyllum demersum ), as carbohydrate sources in biofloc system for Nile tilapia ( Oreochromis niloticus )

Abstract

Two freshwater macrophytes, water (Eichhornia crassipes) and coontail (Ceratophyllum demersum), were evaluated as carbon sources in biofloc system for Nile tilapia (Oreochromis niloticus), in comparison with molasses and a RAS with 10% water exchange daily (control). All-male tilapia (9.35 g) were stocked in 70-L fibreglass tanks at 10 fish tank −1 and fed on a commercial diet (30% cp) for 60 days. The average water temperature, pH and dissolved oxygen (DO) did not significantly differ (p > 0.05) among all treatments. Total ammonia-nitrogen (TAN) was significantly lower in the control group (0.11 mg L −1 ) than in biofloc treatments (0.15-0.17 mg L −1 ). Nitrite (NO 2 -N) concentrations were significantly lower, while nitrates (NO 3 -N) higher, in bioflocbased treatments (20.23-25.77 mg L −1 ) than in the control group (12.85 mg L −1 ). Biofloc volume (BFV) (28.17-33.50 ml L −1 ) and total suspended solids (TSS) (691-824 mg L −1 )were not significantly different among molasses and macrophytes treatments. The control group displayed lower growth rates and feed efficiency than macrophytesbased groups. Blood parameters, immunological responses, digestive enzymes activities, liver function enzymes and upregulation of IFNγ, TNFα and IL-8 genes were significantly better in molasses-and macrophytes-treated tanks than the control group. These results suggest that water hyacinth and coontail can be used as costless, eco-friendly carbon sources in biofloc systems.

Partial Replacement of Fish Meal with an Aquatic Macrophyte, Ceratophyllum demersum in the Diet of Common Carp, Cyprinus carpio var. communis Fingerlings

“…In the present study, C. demersum, a macrophyte, has been utilized as a good source for partial replacement of fish meal due to its capacity to produce significant amounts of biomass in a little period of time and its favorable biochemical profile. C. demersum can be utilized for culture in a cost-effective, safe, accessible, and ecologically friendly way [42]. Additionally, it is a fantastic phytoremediator for treating wastewater and eliminating contaminants like nitrate and phosphates [43].…”

Use of Coontail as a natural phytoremediation feed additive for common carp

“…Irabor et al (2022) noted that the inclusion of 40% duckweed meal in the diet of juvenile catfish is best for optimum growth performance without any adverse effects. In another aspect, Komara et al (2022) showed that coontail (C. demersum) is an inexpensive, safe, widely available and environmentally friendly carbohydrate source for Nile tilapia culture in the biofloc system. In another investigation, Catfish was found to have better growth performance when fed with 'Azolla' grown from wastewater, replacing up to 10 g kg -1 of fishmeal protein (Rahmah el.al 2022).…”