Effects of photoperiod on growth performance and melanogenesis pathway for skin pigmentation of Malaysian red tilapia

Abstract

Farming of red tilapia is increasing rapidly. However, its commercial farming development is challenged by lack of clear information on genetic basis for skin colour and pigmentation differences due to environmental changes. This study investigated the effects of photoperiod (light:dark, L:D) on the growth and skin colour variation of Malaysian red tilapia. A total of 180 fish weighing 150.48 ± 0.44 g were reared under natural photoperiod (13L:11D, control), prolonged lightness (24L:0D) and prolonged darkness (0L:24D) in three replicates for 78 days. The weight gain of fish cultured under both prolonged light and darkness were significantly higher than fish under natural photoperiod. The tyrosinase level in ventral skin was significantly higher for fish cultured under prolonged darkness condition than in the other two photoperiod regimes. Contrary, the cysteine level in the dorsal skin was significantly higher in the fish cultured under natural photoperiod than in prolonged light and darkness. The relative mRNA expressions of SRY‐related HMG‐Box 10 (sox 10), tyrosine (tyr), tyrosine‐related protein 1 (tyrp‐1) and solute carrier family 7 member 11 (slc7a11) genes were significantly higher in ventral skin of fish under prolonged darkness than the other two photoperiods. This study demonstrates that photoperiod has an impact on melanogenesis and growth of red tilapia. Understanding the effects of photoperiod on genetic basis of red tilapia will help in selective breeding programme of the important economic traits for the development of commercial red tilapia farming.

Arginine supplementation in plant‐rich diets affects growth, feed utilization, body composition, blood biochemical indices and gene expressions of the target of rapamycin signaling pathway in juvenile Asian red‐tailed catfish (Hemibagrus wyckoiides)

“…For instance, GOT and GPT are the most important enzymes in amino acid catabolism, hence are used as indicators of normal liver function in vertebrates (Metón, Mediavilla, Caseras, Cantó, & Baanante, 1999). In addition, the AKP is an enzyme required for phosphate hydrolysis and absorption of nutrients, whereby high concentration indicates hepatic disorder (Malambugi et al, 2020). In the present study, dietary supplementation with Arg had no significant effect on serum GOT, GPT and AKP in juvenile H. wyckioides, suggesting no adverse effects on liver function.…”

A survey of fish behaviour quantification indexes and methods in aquaculture

“…2018; Malambugi et al . 2020), water quality (Braun & Perry 2010; Longhini et al . 2017; Saari et al .…”

“…Non‐image sonar is usually combined with bio‐logging technology to locate and track fish, monitor their behaviour, especially in sea cages (Malambugi et al . 2020).…”

“…Image sonar utilises the echo sounder based on echo synthesis technology (Williamson et al 2017). Non-image sonar is usually combined with biologging technology to locate and track fish, monitor their behaviour, especially in sea cages (Malambugi et al 2020).…”

“…Behaviour is a direct reflection of neural activity. Fish can make a series of behavioural responses to external stimuli, such as light (Karakatsouli et al 2007;Higgs et al 2018;Malambugi et al 2020), water quality (Braun & Perry 2010;Longhini et al 2017;Saari et al 2018), and breeding density (Hong et al 2019) and flow (Breitburg et al 1995). For example, some fish species can reduce irritation by moving away from light sources (Hannah et al 2015;Karlsen et al 2015;Santos et al 2019).…”