The Welfare of Nile Tilapia (Oreochromis niloticus, GIFT Strain) Juveniles Cultured in Different Light Spectra

Abstract

The light spectrum is a vital environmental factor for the culture of fish, and the welfare of farmed fish is a crucial issue in aquaculture. In this study, Nile tilapia (Oreochromis niloticus, GIFT strain) juveniles were exposed to full-spectrum (LW), red (LR), yellow (LY), or blue (LB) light. After the 45-day experiment, growth performance, stress responses, and aggressive behaviors were evaluated, and transcriptomic analysis was carried out. The results revealed that LW and LR positively affected growth performance. At the same time, LY and LB had a negative effect. Light spectrum induced stress responses of juvenile fish exposed to LY, under which the total antioxidant capacity (T-AOC) and cortisol (COR) contents were the highest. The activities of α-amylase (AMS), protease (PES), and lipase (LPS) in the digestive tract showed a similar tendency, indicating that the light spectra altered the digestive enzyme activities and then affected growth. Behavioral analyses showed increased chase and bite activities of tilapia juveniles exposed to LW and LY. The affected functions included the nervous system, muscle morphogenesis, and immune system-related regulation. Enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways include the tryptophan metabolism signaling pathway, protein digestion and absorption signaling pathway, Jak-STAT signaling pathway, arachidonic acid metabolism signaling pathway, and alpha-linolenic acid metabolism signaling pathway. Overall, light spectra influenced the welfare of farmed tilapia juveniles in terms of growth, stress, and behavior. Our results suggested that LR should be used in juvenile tilapia culture.

Quasi-Targeted Metabolomics Approach Reveal the Metabolite Differences of Three Poultry Eggs

“…The aminoacyl-tRNA biosynthesis pathway is crucial for reacting to danger signals and regulating immunity against viral infections [46]. The protein digestion and absorption pathway regulate the hydrolysis and transport of proteins, peptides, and amino acids [47]. Based on these, it is speculated that the differential metabolites between the egg yolk and albumen are mainly related to amino acid metabolism, protein metabolism, and immune performance.…”

Preliminary study on the visual sensitivity of Oreochromis niloticus using LED light source for the aquaculture development in Uganda

“…Growth rate of fingerling O. niloticus was higher under red (627 nm) and green (513 nm) lights than under blue (452 nm) light of LED (Lopez-Betancur et al, 2020). For juvenile O. niloticus (genetically improved farmed tilapia [GIFT] strain), growth rate was higher under red light (625-630 nm) than under yellow (590-595 nm) and blue (450-455 nm) lights of LED, whereas stress response was highest under yellow light and lowest under blue light (Yi et al, 2022). However, weight gain of fingerlings was greater under blue light than under red and white light, although the difference in weight under fluorescent light was not significant (Elsbaay, 2013).…”

Effects of Light Spectrum on Survival, Growth, Physiological, and Biochemical Indices of Redclaw Crayfish (Cherax quadricarinatus) Juveniles

“…Besides inducing oxidative stress responses, spectra also affect the expression levels of genes associated with growth or molting in aquatic organisms. For example, juvenile Nile tilapia (Oreochromis niloticus) raised under redlight spectrum conditions exhibited significant upregulation of the α-amylase (α-AMY) gene, promoting their growth [18]. Juvenile mud crabs (Scylla paramamosain) exposed to white and blue light exhibited downregulation of the molting inhibitory hormone (MIH) gene and increased molting frequency [19].…”