Light Limitation Alters Water Quality, Biofloc Composition, Zooplankton Community, and Performance of the Whiteleg Shrimp (Litopenaeus vannamei) Reared with Intensive Biofloc

Said Et Al., Mohamed M.

doi:10.21608/ejabf.2024.355970

Light Limitation Alters Water Quality, Biofloc Composition, Zooplankton Community, and Performance of the Whiteleg Shrimp (Litopenaeus vannamei) Reared with Intensive Biofloc

Document Type : Original Article

Author

Mohamed M. Said et al.

10.21608/ejabf.2024.355970

Abstract

An 18-week experiment was performed to explore light limitation effects on water profile, biofloc analysis, zooplankton population, growth, and proximate body analysis of whiteleg shrimp (Litopenaeus vannamei) grown in biofloc system. The experiment was conducted in six 36m³ cement tanks with a water volume of 30m³. Post larvae of L.vannamei shrimp (0.02± 0.0001g) were stocked in tanks at a stocking density of 200animal/m³. The experiment was consisted of two treatments: T1: without light limitation and T2: with light limitation. Significantly higher dissolved oxygen (5.34± 0.080mg/l) was found in T2 compared to (5.01± 0.056mg/l) the units of T1. Moreover, significantly higher pH was observed in T2. Turbidity (NTU) and floc volume (ML/L) were significantly higher in T1 (60.60± 2.51 and 19.73± 0.726, respectively) compared to (48.05± 1.90 and 17.13± 0.41, respectively) the light- limited group. Furthermore, significantly higher survival rate was observed in T2 when compared with T1 (97.20± 0.153 vs 94.97± 0.696%, respectively). Additionally, final shrimp biomass (Kg) and biomass increase percentage were significantly greater in T2 (74.02± 0.43 and 411.25± 3.10, respectively) compared to (71.53± 0.55 and 397.38± 3.10, respectively) T1. FCR and PER were significantly improved in the light- limited group (1.32± 0.007 and 1.98± 0.010), as compared with (1.37± 0.008 and 1.92± 0.011, respectively) T1. Furthermore, significantly higher flocs protein content (17.97± 0.40%) was found in T1 compared to (15.62± 0.32 %) T2. Additionally, significantly higher total zooplankton count (141560orgs/m³ ± 2163.82) was observed in T1 compared to (65350 orgs/m³± 240.90) T2. Under biofloc system, light limitation improved biomass, survival rate, feed utilization, and water quality, while biofloc composition and zooplankton abundance were negatively affected.

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