Effects of light intensity on growth, immune response, plasma cortisol and fatty acid composition of juvenile Epinephelus coioides reared in artificial seawater☆
Introduction
Environmental factors play an important role in regulating reproduction of different animals including fish (Maitra et al., 2006). Light is one of the major environmental factors and synchronizes from embryo development to sexual maturation of fish (Biao et al., 2012, Villamizar et al., 2011). Studies have shown that most marine fish are visual feeders and need a minimal threshold light intensity to be able to develop and grow normally (Blaxter, 1986, Hunter, 1981). However, the optimum light intensity for feeding is specific to each species, with either high or low light intensity potentially being stressful or even lethal for some fish species (Boeuf and Le Bail, 1989, Hunter, 1981).
Epinephelus coioides (grouper) is one of most important aquaculture species in China and Southeast Asian countries due to its high commercial value. In the last decades, a number of studies have focused on the investigation of grouper for aquaculture, artificial breeding and disease (Stuart and Drawbridge, 2011, Yoseda et al., 2008). Also, many studies have reported the effect of light on larval growth performance and physiology (Chatain and Ounais-Guschemann, 1991, Dave et al., 2009, Inayah and Jian, 2009, Villamizar et al., 2011). However, only a few studies have reported the effects of light intensity on juvenile fish (Boeuf and Le Bail, 1989, Stefansson et al., 1993). Currently, factories have been established to farm groupers in inland areas of China using artificial seawater (Peng et al., 2008). With respect to commercial production, the use of artificial light regimes is widely accepted as tools for enhancing productivity within the grouper industry. However, no lighting systems have been specifically tuned to aquaculture rearing systems (Herve et al., 2007). In order to provide a theoretical basis to underpin fish factory farming in artificial seawater, we investigated the effects of light intensity on growth, immune response, plasma cortisol and fatty acid composition of juvenile E. coioides under recirculating seawater water system.
Section snippets
Fish and feeding
The experiment was performed in the Marine Science Laboratory of Nanjing Agricultural University. Juvenile E. coioides were purchased from the Qingdao Universal Aquaculture Company of China in March, 2012. The fish acclimated to laboratory conditions for 15 days. During the acclimation period, the juveniles were fed once daily (at 8 a.m.) with commercial feed. Selected healthy juveniles (average weight 22.5 ± 0.6 g) were randomly divided into five groups for the light intensity treatments at 0 lx,
Growth and survival
Table 1 showed that final body weight, weight gain rate (WG, %) and specific growth rate (SGRd) were significantly higher at 320–1150 lx and lower at 0 lx (p ≤ 0.05) than in the other treatments. The final survival of juvenile E. coioides varied from 86.7% to 100% in different treatments, with the lowest survival being at 0 lx (p ≤ 0.05).
Immune responses
Light intensity had a significant effect on the immune response of juvenile E. coioides. Activities of ACP and T-SOD and concentration of NO were the highest at
Discussion
In aquaculture, light intensity is a limiting factor depending on water depth and turbidity, eliciting differential responses in different fish species at various developmental stages (Boeuf and Le Bail, 1989). Wallace et al. (1988) observed better growth in 0.7 g fry Salmo salar maintained for 35 days at 700 lx (compared to 200, 50 and 10 lx). Chatain and Ounais-Guschemann (1991) found that the best light intensity for the Sparus aurata growth was 1300 lx. Puvanendran and Brown (2002) found that
Conclusions
In artificial seawater in the recirculating water system, E. coioides larvae reared at light intensity from 320 to 1150 lx grew quickly, were healthy and accumulated unsaturated fatty acids. Therefore, in the actual production, it is important to control the light intensity at the optimal level. However, given that our study was based on juvenile E. coioides, it remains to be established whether adult E. coioides would be affected by light intensity in a similar manner or not.
Acknowledgments
The authors are grateful for the financial support of the National Key Projects of Scientific and Technical Support Programs funded by the Ministry of Science and Technology of China (No. 2011BAD13B09) and the Project of a Special Fund for Public Welfare Industrial (Agriculture) Research of China (No. 200903001-5).
References (50)
A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein dye binding
Analytical Biochemistry
(1976)- et al.
Inhibition of nitrite formation from hydroxylammoniumchloride: a simple assay for superoxide dismutase
Analytical Biochemistry
(1976) - et al.
Yeast glucan induces increase in lysozyme and complement-mediated haemolytic activity in Atlantic salmon blood
Fish & Shellfish Immunology
(1992) - et al.
Immune and enzyme histochemical characterization of leukocyte populations within lymphoid and mucosal tissues of Atlantic halibut (Hippoglossus hippoglossus)
Fish & Shellfish Immunology
(2006) - et al.
Effects of different dietary levels of cottonseed meal protein hydrolysate on growth, digestibility, body composition and plasma biochemical indices in crucian carp (Carassius auratus gibelio)
Animal Feed Science and Technology
(2010) - et al.
Lipid and n-3 requirement of Sparus aurata larvae during starvation and feeding
Aquaculture
(1989) - et al.
Dietary administration of the probiotic, Bacillus subtilis E20, enhances the growth, innate immune response, and disease resistance of the grouper, Epinephelus coioides
Fish & Shellfish Immunology
(2012) - et al.
Foraging, growth and survival of Atlantic cod, Gadus morhua, larvae reared in different light intensities and photoperiods
Aquaculture
(2002) - et al.
The effect of light intensity and green water on survival and growth of cultural larval California yellowtail (Seriola lalandi)
Aquaculture
(2011) - et al.
Effects of light during early larval development of some aquacultured teleosts
Aquaculture
(2011)
Observations on the effect of light intensity on the growth of Arctic charfingerlings (Salvelinus alpinus) and salmon fry (Salmosalar)
Aquaculture
Dietary sodium alginate administration affects fingerling growth and resistance to Streptococcus Sp. and iridovirus, and juvenile non-specific immune responses of the orange-spotted grouper, Epinephelus coioides
Fish & Shellfish Immunology
Influence of light intensity on feeding, growth, and early survival of leopard coral grouper (Plectropomus leopardus) larval under mass-scale rearing conditions
Aquaculture
Physiological changes in fish from stress in aquaculture with emphasis on the response and effects of corticosteroids
Annual Review of Fish Diseases
Effects of fluctuating light intensity on molting frequency and growth of Litopenaeus vannamei
Aquaculture
Development of sense organs and behaviour of teleost larvae with special reference to feeding and predator avoidance
Transactions of the American Fisheries Society
Does light have an influence on fish growth?
Aquaculture
The essential fatty acid requirement of milkfish
Fish Physiology and Biochemistry
The relationship between light and larvae of Sparus aurata
The effects of tank color and light intensity on growth, survival, and stress tolerance of white seabass, Atractoscion nobilis, larvae
Journal of the World Aquaculture Society
Effect of light intensity on growth, survival and skin color of juvenile Chinese longsnout catfish
Aquaculture
Colorimetric method for determination of sugars and related substances
Analytical Chemistry
Effects of photoperiod and light intensity on growth and activity of juvenile haddock (Melanogrammus aeglefinus)
Aquaculture
Response to short term starvation of growth, haematological, biochemical and non-specific immune parameters in European sea bass (Dicentrarchus labrax) and blackspot sea bream (Pagellus bogaraveo)
Marine Environmental Research
The effect of spectral composition and light intensity on melatonin stress and retinal damage in post-smolt Atlantic salmon, Salmo salar
Aquaculture
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No conflict of interest in the paper.