The effect of rhythmic light color fluctuation on the molting and growth of Litopenaeus vannamei

Abstract

Experimental ecology methodology was used to investigate the effect of rhythmic light color fluctuation on the molting and growth of Litopenaeus vannamei. Molting and growth performance of shrimp were tested under the following treatments: three constant light color treatments (Yellow light, “Y”; Green light, “G”; and Blue light, “B”) and three rhythmic fluctuating light color treatments (Blue light to Yellow light, “BY”; Blue light to Green light, “BG”; and Green light to Yellow light, “GY”). The initial wet body weight of shrimp was 1.212 ± 0.010 g (mean ± S.E.). After 45-day experiment, the weight gain (WG) and the specific growth rate (SGR d) of shrimp in B treatment were the smallest. This might be due to the lowest energy allocation to growth and the highest energy allocation to excretion. Opposite to what was observed in the B treatment, shrimp in BG treatment exhibited highest WG and SGR d. This might be due to the high energy allocation to growth rather than to excretion. Thus, it is reasonable to conclude that suitable fluctuation of light color can promote the growth of L. vannamei. No significant difference was found in feed intake (FI d) of shrimp in all treatments ( P > 0.05). The results indicated that the maximal food conversion efficiency (FCE d) of shrimp occurred in BG treatment, with the minimal in B treatment. There was statistically significant difference of FCE d between BG and B treatments ( P < 0.05). The molting rate (MF) in three rhythmic fluctuating light color treatments was higher than that in three constant light color treatments ( P < 0.05). A correlation between MF and growth in every regime was established.