Impact of Different Colors of Artificial Light on Pigmentation and Growth Performance of Hybrid Red Tilapia (Oreochromis mosambicus × O. hornorum) Reared in Saline Well Water

Abstract

Four light colors (red, white, green and blue) were tested to evaluate their effects on both body color enhancement and growth performance of Florida red tilapia (Oreochromis mosambicus × O. hornorum). Fish were stocked in 12 fiberglass tanks, (each of 2 m3 water volume), at a stocking rate of 100 fish per tank with average initial weight of 2.66 g/fish, three replicates for each treatment. Fish were fed on a commercial diet containing 25% protein, two meals per day with a daily feeding rate of 7% in the first two weeks, then reduced to 5% until the end of the experimental period (6 weeks). The results of this study reveals that there are no significant differences (p>0.05) in growth performance indexes between treatments. However, fish exposed to red color showed highest growth values. With the same trend, results of survival percent and condition factor showed no significant differences between treatments. Significant differences (p≤0.05) are observed in the whole body chemical composition between treatments. Fingerlings that are exposed to blue color has the highest value of dry matter content, while, the lowest value is observed in fingerlings exposed to red color. Feed utilization (FI, FCR and PER) do not significantly affect the lighting color, while protein and energy utilization (PPV and EU) are significantly affected. Concerning the red color accumulated in the fish body, the fingerlings which are exposed to the blue color achieved the best β-carotene value (211.25 IU/100 g fish) with highly significant differences compared with other treatments. The content of β-carotene in blue color treatment is 8, 9, and 16 folds comparing with green, white, and red colors, respectively. Also, Red tilapia fish with black spots in the blue treatment were 12%, compared with 29% in green, 56% in white and 52% in red colors.It could be concluded that cultivating Red tilapia in a full saline well water using the artificial blue color will significantly improve not only the pigmentation of Red tilapia, the quality of fish in terms of the content of dry matter, but also the protein and the energy utilization of the consumed feed.

Effects of Colored Light on Growth and Nutritional Composition of Tilapia, and Biofloc as a Food Source

“…This could be a cause of fish mortality because the green light may create stressful environment and increase cortisol levels. A high level of cortisol also affects the nutritional composition of tilapia, causing high moisture levels and low protein levels [45], which agree with our results. The low level of protein can be attributed to an intensive use of muscle protein to get higher energy than that obtained from food, which could be caused by the stress due to green light [46].…”

“…Aly et al [45] reported that hybrid red tilapia in saline water had a lower growth performance under blue light and other experimental conditions. These results were attributed to a reduced vision of the fish under green light, which reduced feeding (also see [47]).…”

Environmental colour impact on the life of lower aquatic vertebrates: development, growth, physiological and biochemical processes

“…A number of experimental studies were carried out at the important object of fish farming -Nile tilapia (Oreochromis niloticus). The results show that hybrid tilapia individuals reared under red light were larger than those, grown in blue illumination Aly et al 2017). The study by showed that the environmental colour did not affect weight gain in Nile tilapia when fish were held individually; however, the yellow colour seemed to support more homogeneous growth of fish in groups, whereas the red colour increased growth variability, as expressed by coefficient of variation in final weight.…”

“…; Aly et al . ). The study by Luchiari and Freire () showed that the environmental colour did not affect weight gain in Nile tilapia when fish were held individually; however, the yellow colour seemed to support more homogeneous growth of fish in groups, whereas the red colour increased growth variability, as expressed by coefficient of variation in final weight.…”

“…visit frequency in coloured compartments) and growth rate as well as food intake. Detailed studies were carried out on fingerlings Oncorhynchus mykiss (Aly et al 2017). Feed assimilation did not show any dependence from illumination colour, while protein and energy utilization depended on it significantly.…”