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The effect of rhythmic light color fluctuation on the molting and growth of Litopenaeus vannamei
Aquaculture 314 (2011) 210–214
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Aquaculture j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / a q u a - o n l i n e
The effect of rhythmic light color fluctuation on the molting and growth of Litopenaeus vannamei Biao Guo a,b, Fang Wang a,⁎, Shuanglin Dong a, Qinfeng Gao a a b
The Key Laboratory of Mariculture, Ministry of Education, Fisheries College, Ocean University of China, Qingdao, 266003, People's Republic of China Ocean College of Hebei Agricultural University, Qinhuangdao, 066000, People's Republic of China
a r t i c l e
i n f o
Article history: Received 10 August 2010 Received in revised form 7 February 2011 Accepted 15 February 2011 Available online 21 February 2011 Keywords: Litopenaeus vannamei Light color change Growth Molting Energy allocation Body composition
a b s t r a c t 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 (SGRd) 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 SGRd. 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 (FId) of shrimp in all treatments (P N 0.05). The results indicated that the maximal food conversion efficiency (FCEd) of shrimp occurred in BG treatment, with the minimal in B treatment. There was statistically significant difference of FCEd between BG and B treatments (P b 0.05). The molting rate (MF) in three rhythmic fluctuating light color treatments was higher than that in three constant light color treatments (P b 0.05). A correlation between MF and growth in every regime was established. Crown Copyright © 2011 Published by Elsevier B.V. All rights reserved.
1. Introduction The environmental condition of natural ponds always changes with day and night alternation and weather changes. The ingredients of spectra also differ in different aquifers and when the water turbidity value changes. Blue light with a wavelength about 470 nm can transmit furthest in clean seawater, while red and ultraviolet lights be quickly absorbed when penetrating through clean seawater (Jerlov, 1968). Coastal waters and those seawaters rich in plankton and dissolved organic substance may absorb or scatter blue light so much that the transmitted light shifts from blue–green to green– orange region of the spectra (Blaxter, 1968; McFarland, 1986). High plankton density and high levels of dissolved substances in the seawater of shrimp ponds result in decreased light transmittability, particularly for blue light. Moreover, with the increase of suspended particles and dissolved organic matters, the light transmitted to water depths shifts from blue region to the green region of the spectra (McFarland, 1986). Shrimps living in natural waters move around in different water layers and thus, experience different light colors.
⁎ Corresponding author. Tel./fax: + 86 532 82032435. E-mail address: [email protected] (F. Wang).
Many studies have been focused on the effect of light color in crustaceans. It was found that there was significant difference in behavior of crustaceans under different light color conditions (Le Reste, 1970; Moller and Naylor, 1980). Xu et al. (2003) reported that the feed intake in Macrobrachium nipponense was the most active under red light due to its high sensitivity to this color. Wang et al. (2003) indicated that the growth and molting of Fenneropenaeus chinensis differ significantly under different light color conditions. F. indicus were more active when exposed to blue light. Hence, its growth is slower because more energy was allocated to respiration (Le Reste, 1970; Emmerson, et al., 1983). However, the spawning capacity of F. indicus in blue or green light was significantly higher than that in natural light (Emmerson et al., 1983). Under the blue or green light condition, the ovarian maturation of Litopenaeus setiferus and Farfantepenaeus duorarum was faster and the number of spawn was increased (William et al., 1984; Caillouet, 1973). All the above studies were conducted under constant light conditions and the results laid a basis for further understanding of the effect of light color on the physiological ecology of shrimps. The traditional Shelford's Law of tolerance assumed that the animals, when adapting to a variety of environmental factors, have a best fit point, at which the highest survival and growth rates are reached (Shelford, 1931). However, some studies on shrimp found
0044-8486/$ – see front matter. Crown Copyright © 2011 Published by Elsevier B.V. All rights reserved. doi:10.1016/j.aquaculture.2011.02.023
B. Guo et al. / Aquaculture 314 (2011) 210–214
that cyclical fluctuating environmental factors (temperature and salinity) can promote their growth (Tian et al., 2006; Mu et al., 2005; Din et al., 2008); Thus, More research is needed to determine the range of fluctuation in a variety of environmental variables required for optimum growth in shrimp. Although the effect of changed light color on maturity of shrimp has attracted researchers' attention (Hillier, 1984), there appears no report about the effects on the growth and molting of shrimp. Our hypothesis, therefore, is that the growth and molting of shrimp under the changed light color condition was different from that under a single light color condition. The objective of this study is to test the hypothesis by measuring the growth and molting of Litopenaeus vannamei under three single light color treatments and three rhythmic fluctuating light color treatments, and to examine its mechanisms by means of estimating their energy budgets. Our results may shed light on how the changed light color affects the growth and molting of L. vannamei.
2. Materials and methods 2.1. Experimental shrimp and acclimation L. vannamei juveniles were obtained from Baorong Aquaculture Corporation, Qingdao, PR China. After transferred to the laboratory, shrimps were acclimated in tanks (170 cm × 75 cm × 35 cm, water volume: 450 L) for 10 days. Seawater was pre-filtered using a sand filter. One-half to two-thirds of the tank water was daily exchanged with fresh seawater to ensure high water quality. During acclimation period, shrimps were fed to satiation twice daily (at 6 a.m. and 4 p.m.) with a commercial feed (crude protein, 43.39% ± 0.22%; fat, 9.74% ± 0.30%; ash, 9.91% ± 0.05% and moisture, 8.41% ± 0.06%; Mawei Fishery Feed Co., Ltd., Fujian, PR China). A salinity of 28–30 ppt, a temperature of 24 °C–25 °C, a light intensity of 100 lx and a photoperiod of 14 h light:10 h dark were maintained.
2.2. Experimental design Three constant light color treatments (Yellow light, “Y”; Green light, “G”; and Blue light, “B”, using 36 W Huaxing Fluorescent Lamp) and three rhythmic fluctuating light color treatments (Blue light changed to Yellow light, “BY”; Blue light changed to Green light, “BG”; and Green light changed to Yellow light, “GY”) were applied. The peak wavelength of the three types of color lights was 580 nm (yellow light), 525 nm (green light) and 435 nm (blue light), respectively, which was measured by Department of Physics, Ocean University of China. The rhythmic fluctuating light color treatments were defined as follows: a 14-hour illumination followed by 10-hour darkness. In addition, the 14-hour illumination was further split into two stages: the first half (7 h) with the short wavelength light and the other half (7 h) with the long wavelength light. The photoperiod cycle was repeated throughout the experimental period. Four replicates were set up for the experiment on each regime. Twenty-four glass aquaria (45 cm × 25 cm × 3 0 cm, water volume: 35 L) were used for shrimp rearing. Each aquarium held five individuals and was covered with a 5-mm thick screen to prevent the shrimp from jumping out. The different light treatment experiments (shaded from each other) were carried out in one room where temperature was controlled using an air conditioner. The lamps were hung 60–80 cm above the aquaria. The same illumination intensity at the bottom of the aquaria was realized by adjusting the distance between the lamps and water surface and the number of light bulbs. The luminance at the bottom of experimental aquaria was 300 ± 50 lx, which was measured by an underwater illumination photometer (JD1A, made in Shanghai Xuelian Instruments Co.).
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2.3. Rearing condition During the experiment period, dissolved oxygen in tanks was maintained above 6.0 mg/L, pH around 7.8, ammonialess than 0.24 mg/L, seawater temperature 25 ± 0.5 °C and salinity within 28 to 30 ppt. Photoperiod and water exchange rates were the same as those in the acclimation condition. 2.4. Experimental procedure and samples collection After 24-hour feed deprivation, 150 size-selected shrimp (with initial wet body weight 1.212 ± 0.010 g, mean ± S.E.) were pooled into a large fiberglass tank. Among the pooled shrimps, 30 were randomly sampled for later analysis (including initial dry weight, amount of energy and protein in shrimp). The remainder were randomly picked up, individually weighed and stocked into 24 aquaria with each aquarium holding five individuals. During the experiment, the shrimps were fed twice a day (at 6 a.m. and 4 p.m.). 2.5 h after feeding, the uneaten feed and feces were collected into cups by siphon, settled, and dried. The molted shells were also collected. The collected uneaten feed, feces and shells were dried at 65 °C, and kept for further analysis. After the 45-day experiment, all the shrimp were sampled and dried at 65 °C for 48 h. 2.5. Estimation of energy budget and proximate body composition The energy contents of the shrimp bodies, feed, feces and molted shells were measured by Parr 1281 Oxygen Bomb Calorimeter. The energy budget was calculated by using the following equation (Petrusewicz and Macfadyen, 1970): C=G+F+U+E+R where C is the energy consumed in food; G, the energy deposited for growth; F, the energy lost in feces; U, the energy in excretion; E, the energy spent for exuviate; and R, the energy for respiration. The estimation of U was based on the nitrogen budget equation (Levine and Sulkin, 1979; Lemos and Phan, 2001): U = ðCN −GN −FN −EN Þ × 24830 where CN is the nitrogen consumed from food; GN, the nitrogen deposited in shrimp body; FN, the nitrogen lost in feces; EN, the nitrogen lost in molting; 24,830, the energy content in excreted nitrogen per gram (J/g). The nitrogen contents in the formulated feed, shrimp, feces and molting shell were determined by Kjeldahl method. The value of R was calculated by re-arranging the above energy budget equation: R = C–G–F–U–E Five samples were taken for chemical composition analysis. Crude protein content was estimated from nitrogen content, which was measured on a Vario EL III Elementar. Crude lipid was estimated using the Soxhlet method, and ash was determined by combustion at 550 °C for 12 h (Dong et al., 2006). Data on crude protein, crude lipid, ash, and moisture were expressed in terms of wet body weight. 2.6. Calculation of data and statistical analysis The relative weight gain rate (WG, %), molting rate (MF, %.day−1), specific growth rate (SGRd), feed intake (FId) and food conversion efficiency (FCEd) were calculated on a dry weight basis using the following equations: WG = 100 ðWt −W0 Þ = W0 × 100
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MF = ðNm = Ns Þ = T
Table 2 The SGRd, FId and FCEd of L. vannamei in different light regimes.
−1 = 100 × ðln W2 −ln W1 Þ = T SGRd %:day −1 = 100 × F = ½T × ðW2 + W1 Þ = 2 FId %B:W:day FCEd ð%Þ = 100 × ðW2 −W1 Þ = F where, Wt and W0 are the final and initial wet body weight of the shrimp, respectively; Nm, molting frequency; Ns, the number of shrimps per aquarium; W2 and W1, the final and initial dry body weight of the shrimp, respectively; T, the time of the experiment lasted; F, the total food consumed in dry weight. Experimental data were analyzed using SPSS 11.0 (SPSS Inc., Richmond, CA, USA), with possible differences among data being tested by ANOVA. Duncan's multiple range tests were used to compare the differences between treatments. P b 0.05 was accepted as the level of statistical significance. 3. Results 3.1. Growth and molting Significant difference in molting of L. vannamei was observed under different light color regimes (P b 0.05). The MF in all three rhythmic fluctuating light color treatments was higher than those in constant light color treatments (P b 0.05). Among three constant light color treatments, the MF with G treatment was the maximum (5.97%) and the MF with B treatment was the minimum (4.82%). There was a significant difference between G and B treatments (P b 0.05). However, no significant MF difference was observed between Y and either of the other two constant light color treatments (P N 0.05) (Table 1). The WG of shrimps was 314.3%, 326.7%, 279.1%, 340.6%, 359.9% and 360.7% in the Y, G, B, GY, BY and BG treatments, respectively. The WG of shrimp in BG treatment was the highest and significantly higher than that in Y or B treatment (P b 0.05). The WG of shrimp in B treatment was the lowest and significantly lower than those in G treatment and the three rhythmic fluctuating light color treatments (P b 0.05) (Table 1). The SGRd of shrimp also showed the similar trend. The SGRd of shrimps in BG treatment was the highest and significantly higher than those in Y, B, and GY treatments (P b 0.05). The SGRd of shrimp in Y and B treatments was lower than that in G, BY or BG treatment (P b 0.05). The SGRd of shrimp in different regimes showed a declining trend within treatments: BG N BY N G N GY N Y N B (Table 2). 3.2. Feed intake and food conversion efficiency There was no significant difference in FId of shrimps in different light regimes (P N 0.05) (Table 2), but FCEd of shrimp showed significant difference for different light regimes (P b 0.05) (Table 2). The FCEd of shrimp in BG treatment was the highest and significantly higher than those in Y, G, B and GY treatments (P b 0.05). While the FCEd of shrimps showed no significant difference among Y, B and GY
Treatment
SGRd (%.day−1)
FId (%B.W.day−1)
FCEd (%)
Y G B GY BY BG
3.12 ± 0.12a 3.39 ± 0.02bc 3.12 ± 0.10a 3.29 ± 0.03ab 3.52 ± 0.05c 3.58 ± 0.03c
14.64 ± 0.36 14.32 ± 0.17 14.42 ± 0.42 15.12 ± 0.23 15.19 ± 0.21 14.56 ± 0.11
18.43 ± 0.95a 19.14 ± 0.26bc 18.13 ± 0.97a 18.73 ± 0.23ab 19.32 ± 0.39cd 20.37 ± 0.25d
Values (expressed as mean ± S.E., n = 4) with different letters in the same column are significantly different from each other (P b 0.05).
treatments (P N 0.05), the FCEd of shrimps in B treatment was significantly lower than those in G, BY and BG treatments (P b 0.05). 3.3. Energy allocation Significant differences in energy allocation of L. vannamei were observed under different light color regimes (P b 0.05). The energy allocation in the growth of shrimp in BG treatment was the highest and it was significantly higher than that in Y, B or GY treatment (P b 0.05).While the energy allocation in excretion of shrimp in BG treatment was the lowest and it was significantly lower than that in Y, G, B or GY treatment (P b 0.05). In contrast, the energy allocation in the growth of shrimp in B treatment was significantly lower than those in other regimes except for the Y treatment (P b 0.05), and the energy allocation in excretion of shrimp in the same group was significantly higher than those in other regimes (P b 0.05). There was no significant difference in energy allocation in respiration under different light color regimes (P N 0.05). The energy allocation in feces of shrimp in G treatment was significantly lower than those in other regimes (P b 0.05). No significant difference was detected in the energy allocation in feces among Y, GY, BY and BG treatments (P N 0.05), with each of which significantly higher than that in G or B treatment, (P b 0.05). A significant difference was also observed in energy allocation to molting under different light color regimes (P b 0.05), with a similar trend as of MF (Table 3). 3.4. Proximate body composition The moisture of shrimp in Y treatment was the highest, and was significantly higher than those in G, B, BY and BG treatments (P b 0.05). While the moisture of shrimp in BG treatment was significantly lower than those in Y and GY treatments (P b 0.05), no significant difference was detected when compared with other regimes (P N 0.05). There was no significant difference in crude protein content of shrimp among different regimes (P N 0.05). The crude lipid contents in G, B and GB treatments did not show any significant differences (P N 0.05). However, they appeared significantly higher than those in other regimes (P b 0.05). There was also no significant difference in crude lipid content of shrimp among Y, GY and BY treatments (P N 0.05). Ash content among three rhythmic fluctuating light color treatments did not have significantly differences from each other (P N 0.05), but they
Table 1 The growth and molting of L. vannamei in different light regimes. Treatment
Initial wet body weight(g)
Final wet body weight (g)
WG (%)
Survival rate (%)
MF (%.day−1)
Y G B GY BY BG
1.212 ± 0.008 1.214 ± 0.008 1.211 ± 0.006 1.210 ± 0.003 1.211 ± 0.003 1.213 ± 0.004
5.021 ± 0.202b 5.177 ± 0.084bc 4.590 ± 0.155a 5.329 ± 0.111bc 5.567 ± 0.166c 5.589 ± 0.115c
314.3 ± 17.5ab 326.7 ± 8.2bc 279.1 ± 12.9a 340.6 ± 9.8bc 359.9 ± 14.9c 360.7 ± 9.9c
90.0 ± 5.8 90.0 ± 5.8 95.0 ± 5.0 95.0 ± 5.0 90.0 ± 5.8 95.0 ± 5.0
5.05 ± 0.17ab 5.97 ± 0.15b 4.82 ± 0.32a 7.10 ± 0.48c 7.98 ± 0.42c 7.44 ± 0.31c
Values (expressed as mean ± S.E., n = 4) with different letters in the same column are significantly different from each other (P b 0.05).
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Table 3 Allocation of the consumed energy in L. vannamei at different light regimes.a Treatments
G/Cb (%)
R/Cc (%)
U/Cd (%)
F/Ce (%)
E/Cf (%)
Y G B GY BY BG
19.61 ± 0.91ab 21.50 ± 0.44cd 18.32 ± 0.41a 20.01 ± 0.26bc 21.09 ± 0.36bcd 22.57 ± 0.17d
59.01 ± 0.97 60.74 ± 0.50 59.64 ± 0.60 60.08 ± 0.43 59.59 ± 0.38 59.02 ± 0.39
4.96 ± 0.81b 4.45 ± 0.63b 7.54 ± 0.94c 3.76 ± 0.09ab 2.46 ± 0.37a 2.36 ± 0.48a
16.06 ± 0.37c 12.92 ± 0.29a 14.17 ± 0.32b 15.66 ± 0.31c 16.36 ± 0.27c 15.59 ± 0.17c
0.36 ± 0.01ab 0.39 ± 0.02b 0.33 ± 0.00a 0.49 ± 0.01c 0.50 ± 0.03c 0.46 ± 0.01c
a b c d e f
Values (expressed as mean ± S.E., n = 4) with different letters in the same column are significantly different from each other (P b 0.05). G/C (%) = energy for growth/energy consumed in food. R/C (%) = energy for respiration/energy consumed in food. U/C (%) = energy for excretion/energy consumed in food. F/C (%) = energy for feces/energy consumed in food. E/C (%) = energy for exuviate/energy consumed in food.
were significantly higher than those in constant light color treatments (P b 0.05). Among the three constant light color treatments, ash content in Y and B treatments was similar, and it was significantly lower than that in G treatment (P b 0.05) (Table 4). 4. Discussion Studies have shown that different species of crustacean have different sensitivity to light spectra (Chen et al., 1996; Xu et al., 2003). This could be highly related with various habitats of crustacean at different developmental stages (Forward and Gronin, 1979; FanjulMoles and Fuentes-Pardo, 1988; Fanjul-Moles et al., 1992). Moreover, the effects of different spectra on feed and growth of crustacean were different (Le Reste, 1970; Emmerson, et al., 1983; Xu et al., 2003; Wang et al., 2003). In our experiment, the growth of L. vannamei in G treatment was the best and the growth in B treatment was the worst among three constant light color treatments. This agrees quite well with the effect of light color on the growth of F. chinensis (Wang et al., 2003). Under the rhythmic fluctuating light color conditions, both WG and SGRd of shrimp in BY and BG treatments were significantly higher than those in the three constant light color treatments (P b 0.05). The environmental condition of natural pond could change due to the day and night alternation and the change of weather. The ingredients of spectra also differ with different aquifers (Jerlov, 1968) and the water turbidity value changes as well (Blaxter, 1968; McFarland, 1986). It is possible to suggest that in nature, L. vannamei undergoes the changes of spectra during its life cycle. Some researchers simulated the natural environmental fluctuations and found that the suitable fluctuation of environmental factor could promote the growth of crustacean (Tian et al., 2006; Mu et al., 2005; Din et al., 2008). In this study, we found that fluctuations from blue region of the spectra to green or yellow region could promote the growth of L. vannamei. Van Wormhoudt and Ceccaldi (1976) have shown that different wavelengths affect the enzymatic activity in Palaemon serratus shrimp, thus affecting digestibility, assimilation and the growth of shrimp. In our study, the FCEd of shrimps in B treatment was the Table 4 The proximate body composition of L. vannamei in different light regimes. Treatments
Moisture (%)
Crude protein (%)
Crude lipid (%)
Ash (%)
Y G B GY BY BG
77.84 ± 1.09a 75.78 ± 0.68bc 75.82 ± 0.52bc 76.93 ± 1.19ab 76.09 ± 0.52bc 75.55 ± 0.48c
15.96 ± 0.13a 17.32 ± 0.24b 17.74 ± 0.13c 16.57 ± 0.12d 17.26 ± 0.17b 17.70 ± 0.20c
2.80 ± 0.06a 3.00 ± 0.03b 3.00 ± 0.05b 2.81 ± 0.06a 2.85 ± 0.03a 3.02 ± 0.03b
2.90 ± 0.01a 2.95 ± 0.03b 2.89 ± 0.01a 2.98 ± 0.01c 2.99 ± 0.01c 2.95 ± 0.05c
Values (expressed as mean ± S.E., n = 4) with different letters in the same column are significantly different from each other (P b 0.05).
lowest and it was significantly lower than those in G, BY, and BG treatments (P b 0.05). This result suggests that the difference of growth of L. vannamei under different light color treatments might be related to FCEd of shrimp. Previous studies have also shown that metabolic energy accounts for the majority portion in the energy distribution of decapoda crustaceans. Therefore, the change of metabolic energy determined the energy accumulation in growth (Wang et al., 2005; Paul and Akira, 1989). In this study, the energy allocation in excretion under B treatment was about 1.5 times higher than those under BY and BG treatments, although no significant difference was detected in energy allocation in respiration under different light color regimes (P N 0.05). And the energy allocation in growth under the BY or BG treatment was higher than that under B treatment. The difference of energy distribution may be another reason for the variation in shrimp growth. In general, the growth curve of shrimp is similar to other crustaceans, i.e. a ladder-style with much fast growth during each molting process. After molting, the size of crustacean rarely increases until the next molting (Dall et al., 1990). Wang et al. (2004) suggested that the growth of shrimp was correlated to feed, digestion and absorption of food, while the molting was related with the secretion of hormone. So there may be two distinct regulations of these two physical activities. In this study, higher MF resulted in faster growth in shrimps; while for shrimps with poor growth, the MF was relatively low. Thus, there was a clear correlation between growth and molting. Huang (2003) found that shrimp can grow much faster with adequate feed supplies and good nutrition during molting. In our study, the shrimp were fed to satiation using high-quality artificial diet. Thus, the adequate feed supplies and good nutritional conditions were satisfied which might explain the clear correlation between growth and molting. Shearer (1994) indicated that the crude protein and ash level of fish body were mostly determined by endogenous factors (e.g., the size and the developmental stages). Instead, exogenously factors (e.g., temperature, salinity, and diet) did not show any effect on the crude protein level of fish body. In our study, a positive correlation was observed between ash level and the final body weight of shrimp. However, there was no correlation between the crude protein level and the final body weight of shrimps. For example, the size of shrimp in B treatment was the smallest, while the crude protein level was the highest. Miller and Weil (1963) suggested that change of one component of body composition might lead to a change in the content of other components. For instance, moisture difference in shrimps could influence the level of crude proteins. Studies in fish suggested that the lipid level increased with the decrease of moisture level, and the lipid level could be forecasted in use of body weight and moisture level (Spigarelli et al., 1982; Konstantinov and Zdanovich, 1986). Consistent with the results of fish research, the moisture
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level of shrimps in our study had a negative correlation with the corresponding lipid level. In conclusion, our study indicated that the rhythmic light color fluctuations affected the molting and growth of L. vannamei and the fluctuations from blue to green or yellow region of the spectra were beneficial to the growth of L. vannamei. Acknowledgments This work was supported by the Chinese National Natural Science Foundation (grant no. 30571441), the Key Project of Scientific and Technical Supporting Programs funded by Ministry of Science & Technology of China (grant no. 2006BAD09A07) and the project under the Major State Basic Research of China (grant no. 2009CB118706). References Blaxter, J.H.S., 1968. Visual thresholds and spectral sensitivity of herring larvae. J. Exp. Biol. 48, 39–53. Caillouet, C.W., 1973. Ovarian maturation induced by eyestalk ablation in pink shrimp Penaeus duorarum Burkenroad. In: Wault, J.W., Boudreaux, J., Jaspers, E. (Eds.), Proe, 3rd A. Meeting. Wil. Mariculture Soc. Louisiana State Univ, Baton Rouge, pp. 205–225. Chen, S.Q., Li, A.J., Wang, C., 1996. The structure and physiological functions of eyes in shrimp (Penaeus chinensis). Mar. Fish. Res. 17, 30–34. Dall, W., Hill, B.J., Rothlisberg, P.C., Sharples, D.J., 1990. The Biology of the Penaeidae. Academic Press, London, San Diego. Din, S., Wang, F., Guo, B., Li, X.S., 2008. Effects of salinity fluctuation on the molt, growth, and energy budget of juvenile Fenneropenaeus chinens. Chin. J. App. Ecol. 19, 419–423 (in Chinese with English abstract). Dong, Y.W., Dong, S.L., Tian, X.L., Wang, F., Zhang, M.Z., 2006. Effects of diel temperature fluctuations on growth, oxygen consumption and proximate body composition in the sea cucumber Apostichopus japonicus Selenka. Aquaculture 255, 514–521. Emmerson, W.D., Hayes, D.P., Ngonyame, M., 1983. Growth and maturation of Peaneus indicus under blue and green light. S. Afr. J. Zool. 18, 71–75. Fanjul-Moles, M.L., Fuentes-Pardo, B., 1988. Spectral sensitivity in the course of the ontogeny of the crayfish Procambarus clarckii. Comp. Biochem. Physiol. 91A, 61–66. Fanjul-Moles, M.L., Miranda-Anaya, M., Fuentes-Pardo, B., 1992. Effect of monochromatic light upon the ERG circadian rhythm during ontogeny in crayfish (Procambarus clarckii). Comp. Biochem. Physiol. 102A, 99–106. Forward, R.B., Gronin, T.W., 1979. Spectral sensitivity of larvae from intertidal crustaceans. J. Comp. Physiol. 133, 311–315. Hillier, A.G., 1984. Artificial conditions influencing the maturation and spawning of subadult Penaeus monodon (Fabricius). Aquaculture 36, 179–184. Huang, G.Q. 2003. The Research about Feeding Behavior and Physiological Ecology of Fenneropenaeus chinensi. PhD Thesis, Ocean university of Qingdao, China (in Chinese).
Jerlov, N.G., 1968. Optical Oceanography. Elsevier, Amsterdam. Konstantinov, A.S., Zdanovich, V.V., 1986. Some features of fish growth at fluctuating temperature. Vopr. Ikhtiol. 26, 971–977. Le Reste, L., 1970. Contribution a l'étude du rhythme d'activité nocture de Penaeus indicus en Parapenaeopsis acclivirostris (Crustacea:Decapoda:Natantia). Cah. Off. Rech. Sci. Tech. outre Mer Oceanogr. 8, 3–10. Lemos, D., Phan, V.N., 2001. Energy partitioning into growth, respiration, excretion and exuvia during larval development of the shrimp Farfantepenaeus paulensis. Aquaculture 199, 131–143. Levine, D.M., Sulkin, S.D., 1979. Partitioning and utilization of energy during the larval development of the xanthid crab, Rithropanopeus harrisii (Gould). J. Exp. Mar. Biol. Ecol. 40, 247–257. McFarland, W.N., 1986. Light in the sea-correlations with behaviours of fishes and invertebrates. Am. Zool. 26, 389–401. Miller, I., Weil, W.B., 1963. Some problems in expressing and comparing body composition determined by direct analysis. Ann. NY Acad. Sci. 153–160. Moller, T.H., Naylor, E., 1980. Environmental influence on locomoter acitivity in Nephrops norvegicus (Crustacea:Decapoda). J. Mar. Biol. Ass. UK 60, 103–113 (in Chinese with English abstract). Mu, Y.C., Wang, F., Dong, S.L., Huang, G.Q., Dong, S.S., 2005. Effects of salinity fluctuation pattern on growth and energy budget of juvenile shrimp Fenneropenaeus chinensis. J. Shellfish. Res. 24, 1217–1221. Paul, A.J., Akira, F., 1989. Bioenergetics of the Alaskan Crab Chionoecetes bairdi (Deeapoda:majidae). J. Crust. Biol. 9, 25–36. Petrusewicz, K., Macfadyen, A., 1970. Productivity of Terrestrial Animals: Principles and Methods. (IBP Handbook No. 13). Blackwell, Oxford. 190 pp. Shearer, K.D., 1994. Factors affecting the proximate composition of cultured fishes with emphasis on salmonids. Aquaculture 119, 63–88. Shelford, V.E., 1931. Some concepts of bioecology. Ecology 123, 455–467. Spigarelli, S.A., Thomas, M.M., Prepejchal, W., 1982. Feeding, growth, and fat deposition by brown trout in constant and fluctuating temperatures. Trans. Am. Fish. Soc. 111, 199–209. Tian, X.L., Dong, S.L., Wang, F., Wu, L.X., 2006. The Effects of thermal amplitude on the growth of Chinese shrimp Fenneropenaeus chinensis Osbeck. Aquaculture 251, 516–524. Van Wormhoudt, A., Ceccaldi, J.H., 1976. Influence de la qualite´ de la lumie´re en e´levage intensif de Palaemon seratus Pennant. In: Persoone, G., Jaspers, G. (Eds.), Mariculture: Proc. 10th Eur. Symp. Mar. Biol., 1. Universa press, Belgium, pp. 505–521. Wang, F., Dong, S.L., Huang, G.Q., Wu, L.X., Tian, X.L., Ma, S., 2003. The effect of light color on the growth of Chinese shrimp Fenneropenaeus chinensi. Aquaculture 228, 351–360. Wang, F., Dong, S.L., Dong, S.S., Huang, G.Q., 2004. Effects of photoperiod on the molting and growth of juvenile Chinese shrimp Fenneropenaeus chinensi. J. Fish. Sci. Chin. 11, 354–359 (in Chinese with English abstract). Wang, F., Zhang, J.D., Dong, S.L., Mu, Y.C., 2005. The effects of light intensity and photoperiod on the growth of juvenile Fenneropenaeus chinensis. J. Ocean. Univ. China. 35, 768–772 (in Chinese with English abstract). William, A., Wurts, Robert, Stickney, R., 1984. A hypothesis on the light requirements for spawning penaeid shrimp, with emphasis on Penaeus setiferus. Aquaculture. 41, 93–98. Xu, Y., Yuan, W.J., Zhao, Y.L., Hu, H., 2003. Influence of light wavelength on the vision of the Macrobrachium nipponense. J. Shanghai. Nor. Univ. (Nat. Sci.) 32, 75–78.
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Aquaculture j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / a q u a - o n l i n e
The effect of rhythmic light color fluctuation on the molting and growth of Litopenaeus vannamei Biao Guo a,b, Fang Wang a,⁎, Shuanglin Dong a, Qinfeng Gao a a b
The Key Laboratory of Mariculture, Ministry of Education, Fisheries College, Ocean University of China, Qingdao, 266003, People's Republic of China Ocean College of Hebei Agricultural University, Qinhuangdao, 066000, People's Republic of China
a r t i c l e
i n f o
Article history: Received 10 August 2010 Received in revised form 7 February 2011 Accepted 15 February 2011 Available online 21 February 2011 Keywords: Litopenaeus vannamei Light color change Growth Molting Energy allocation Body composition
a b s t r a c t 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 (SGRd) 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 SGRd. 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 (FId) of shrimp in all treatments (P N 0.05). The results indicated that the maximal food conversion efficiency (FCEd) of shrimp occurred in BG treatment, with the minimal in B treatment. There was statistically significant difference of FCEd between BG and B treatments (P b 0.05). The molting rate (MF) in three rhythmic fluctuating light color treatments was higher than that in three constant light color treatments (P b 0.05). A correlation between MF and growth in every regime was established. Crown Copyright © 2011 Published by Elsevier B.V. All rights reserved.
1. Introduction The environmental condition of natural ponds always changes with day and night alternation and weather changes. The ingredients of spectra also differ in different aquifers and when the water turbidity value changes. Blue light with a wavelength about 470 nm can transmit furthest in clean seawater, while red and ultraviolet lights be quickly absorbed when penetrating through clean seawater (Jerlov, 1968). Coastal waters and those seawaters rich in plankton and dissolved organic substance may absorb or scatter blue light so much that the transmitted light shifts from blue–green to green– orange region of the spectra (Blaxter, 1968; McFarland, 1986). High plankton density and high levels of dissolved substances in the seawater of shrimp ponds result in decreased light transmittability, particularly for blue light. Moreover, with the increase of suspended particles and dissolved organic matters, the light transmitted to water depths shifts from blue region to the green region of the spectra (McFarland, 1986). Shrimps living in natural waters move around in different water layers and thus, experience different light colors.
⁎ Corresponding author. Tel./fax: + 86 532 82032435. E-mail address: [email protected] (F. Wang).
Many studies have been focused on the effect of light color in crustaceans. It was found that there was significant difference in behavior of crustaceans under different light color conditions (Le Reste, 1970; Moller and Naylor, 1980). Xu et al. (2003) reported that the feed intake in Macrobrachium nipponense was the most active under red light due to its high sensitivity to this color. Wang et al. (2003) indicated that the growth and molting of Fenneropenaeus chinensis differ significantly under different light color conditions. F. indicus were more active when exposed to blue light. Hence, its growth is slower because more energy was allocated to respiration (Le Reste, 1970; Emmerson, et al., 1983). However, the spawning capacity of F. indicus in blue or green light was significantly higher than that in natural light (Emmerson et al., 1983). Under the blue or green light condition, the ovarian maturation of Litopenaeus setiferus and Farfantepenaeus duorarum was faster and the number of spawn was increased (William et al., 1984; Caillouet, 1973). All the above studies were conducted under constant light conditions and the results laid a basis for further understanding of the effect of light color on the physiological ecology of shrimps. The traditional Shelford's Law of tolerance assumed that the animals, when adapting to a variety of environmental factors, have a best fit point, at which the highest survival and growth rates are reached (Shelford, 1931). However, some studies on shrimp found
0044-8486/$ – see front matter. Crown Copyright © 2011 Published by Elsevier B.V. All rights reserved. doi:10.1016/j.aquaculture.2011.02.023
B. Guo et al. / Aquaculture 314 (2011) 210–214
that cyclical fluctuating environmental factors (temperature and salinity) can promote their growth (Tian et al., 2006; Mu et al., 2005; Din et al., 2008); Thus, More research is needed to determine the range of fluctuation in a variety of environmental variables required for optimum growth in shrimp. Although the effect of changed light color on maturity of shrimp has attracted researchers' attention (Hillier, 1984), there appears no report about the effects on the growth and molting of shrimp. Our hypothesis, therefore, is that the growth and molting of shrimp under the changed light color condition was different from that under a single light color condition. The objective of this study is to test the hypothesis by measuring the growth and molting of Litopenaeus vannamei under three single light color treatments and three rhythmic fluctuating light color treatments, and to examine its mechanisms by means of estimating their energy budgets. Our results may shed light on how the changed light color affects the growth and molting of L. vannamei.
2. Materials and methods 2.1. Experimental shrimp and acclimation L. vannamei juveniles were obtained from Baorong Aquaculture Corporation, Qingdao, PR China. After transferred to the laboratory, shrimps were acclimated in tanks (170 cm × 75 cm × 35 cm, water volume: 450 L) for 10 days. Seawater was pre-filtered using a sand filter. One-half to two-thirds of the tank water was daily exchanged with fresh seawater to ensure high water quality. During acclimation period, shrimps were fed to satiation twice daily (at 6 a.m. and 4 p.m.) with a commercial feed (crude protein, 43.39% ± 0.22%; fat, 9.74% ± 0.30%; ash, 9.91% ± 0.05% and moisture, 8.41% ± 0.06%; Mawei Fishery Feed Co., Ltd., Fujian, PR China). A salinity of 28–30 ppt, a temperature of 24 °C–25 °C, a light intensity of 100 lx and a photoperiod of 14 h light:10 h dark were maintained.
2.2. Experimental design Three constant light color treatments (Yellow light, “Y”; Green light, “G”; and Blue light, “B”, using 36 W Huaxing Fluorescent Lamp) and three rhythmic fluctuating light color treatments (Blue light changed to Yellow light, “BY”; Blue light changed to Green light, “BG”; and Green light changed to Yellow light, “GY”) were applied. The peak wavelength of the three types of color lights was 580 nm (yellow light), 525 nm (green light) and 435 nm (blue light), respectively, which was measured by Department of Physics, Ocean University of China. The rhythmic fluctuating light color treatments were defined as follows: a 14-hour illumination followed by 10-hour darkness. In addition, the 14-hour illumination was further split into two stages: the first half (7 h) with the short wavelength light and the other half (7 h) with the long wavelength light. The photoperiod cycle was repeated throughout the experimental period. Four replicates were set up for the experiment on each regime. Twenty-four glass aquaria (45 cm × 25 cm × 3 0 cm, water volume: 35 L) were used for shrimp rearing. Each aquarium held five individuals and was covered with a 5-mm thick screen to prevent the shrimp from jumping out. The different light treatment experiments (shaded from each other) were carried out in one room where temperature was controlled using an air conditioner. The lamps were hung 60–80 cm above the aquaria. The same illumination intensity at the bottom of the aquaria was realized by adjusting the distance between the lamps and water surface and the number of light bulbs. The luminance at the bottom of experimental aquaria was 300 ± 50 lx, which was measured by an underwater illumination photometer (JD1A, made in Shanghai Xuelian Instruments Co.).
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2.3. Rearing condition During the experiment period, dissolved oxygen in tanks was maintained above 6.0 mg/L, pH around 7.8, ammonialess than 0.24 mg/L, seawater temperature 25 ± 0.5 °C and salinity within 28 to 30 ppt. Photoperiod and water exchange rates were the same as those in the acclimation condition. 2.4. Experimental procedure and samples collection After 24-hour feed deprivation, 150 size-selected shrimp (with initial wet body weight 1.212 ± 0.010 g, mean ± S.E.) were pooled into a large fiberglass tank. Among the pooled shrimps, 30 were randomly sampled for later analysis (including initial dry weight, amount of energy and protein in shrimp). The remainder were randomly picked up, individually weighed and stocked into 24 aquaria with each aquarium holding five individuals. During the experiment, the shrimps were fed twice a day (at 6 a.m. and 4 p.m.). 2.5 h after feeding, the uneaten feed and feces were collected into cups by siphon, settled, and dried. The molted shells were also collected. The collected uneaten feed, feces and shells were dried at 65 °C, and kept for further analysis. After the 45-day experiment, all the shrimp were sampled and dried at 65 °C for 48 h. 2.5. Estimation of energy budget and proximate body composition The energy contents of the shrimp bodies, feed, feces and molted shells were measured by Parr 1281 Oxygen Bomb Calorimeter. The energy budget was calculated by using the following equation (Petrusewicz and Macfadyen, 1970): C=G+F+U+E+R where C is the energy consumed in food; G, the energy deposited for growth; F, the energy lost in feces; U, the energy in excretion; E, the energy spent for exuviate; and R, the energy for respiration. The estimation of U was based on the nitrogen budget equation (Levine and Sulkin, 1979; Lemos and Phan, 2001): U = ðCN −GN −FN −EN Þ × 24830 where CN is the nitrogen consumed from food; GN, the nitrogen deposited in shrimp body; FN, the nitrogen lost in feces; EN, the nitrogen lost in molting; 24,830, the energy content in excreted nitrogen per gram (J/g). The nitrogen contents in the formulated feed, shrimp, feces and molting shell were determined by Kjeldahl method. The value of R was calculated by re-arranging the above energy budget equation: R = C–G–F–U–E Five samples were taken for chemical composition analysis. Crude protein content was estimated from nitrogen content, which was measured on a Vario EL III Elementar. Crude lipid was estimated using the Soxhlet method, and ash was determined by combustion at 550 °C for 12 h (Dong et al., 2006). Data on crude protein, crude lipid, ash, and moisture were expressed in terms of wet body weight. 2.6. Calculation of data and statistical analysis The relative weight gain rate (WG, %), molting rate (MF, %.day−1), specific growth rate (SGRd), feed intake (FId) and food conversion efficiency (FCEd) were calculated on a dry weight basis using the following equations: WG = 100 ðWt −W0 Þ = W0 × 100
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MF = ðNm = Ns Þ = T
Table 2 The SGRd, FId and FCEd of L. vannamei in different light regimes.
−1 = 100 × ðln W2 −ln W1 Þ = T SGRd %:day −1 = 100 × F = ½T × ðW2 + W1 Þ = 2 FId %B:W:day FCEd ð%Þ = 100 × ðW2 −W1 Þ = F where, Wt and W0 are the final and initial wet body weight of the shrimp, respectively; Nm, molting frequency; Ns, the number of shrimps per aquarium; W2 and W1, the final and initial dry body weight of the shrimp, respectively; T, the time of the experiment lasted; F, the total food consumed in dry weight. Experimental data were analyzed using SPSS 11.0 (SPSS Inc., Richmond, CA, USA), with possible differences among data being tested by ANOVA. Duncan's multiple range tests were used to compare the differences between treatments. P b 0.05 was accepted as the level of statistical significance. 3. Results 3.1. Growth and molting Significant difference in molting of L. vannamei was observed under different light color regimes (P b 0.05). The MF in all three rhythmic fluctuating light color treatments was higher than those in constant light color treatments (P b 0.05). Among three constant light color treatments, the MF with G treatment was the maximum (5.97%) and the MF with B treatment was the minimum (4.82%). There was a significant difference between G and B treatments (P b 0.05). However, no significant MF difference was observed between Y and either of the other two constant light color treatments (P N 0.05) (Table 1). The WG of shrimps was 314.3%, 326.7%, 279.1%, 340.6%, 359.9% and 360.7% in the Y, G, B, GY, BY and BG treatments, respectively. The WG of shrimp in BG treatment was the highest and significantly higher than that in Y or B treatment (P b 0.05). The WG of shrimp in B treatment was the lowest and significantly lower than those in G treatment and the three rhythmic fluctuating light color treatments (P b 0.05) (Table 1). The SGRd of shrimp also showed the similar trend. The SGRd of shrimps in BG treatment was the highest and significantly higher than those in Y, B, and GY treatments (P b 0.05). The SGRd of shrimp in Y and B treatments was lower than that in G, BY or BG treatment (P b 0.05). The SGRd of shrimp in different regimes showed a declining trend within treatments: BG N BY N G N GY N Y N B (Table 2). 3.2. Feed intake and food conversion efficiency There was no significant difference in FId of shrimps in different light regimes (P N 0.05) (Table 2), but FCEd of shrimp showed significant difference for different light regimes (P b 0.05) (Table 2). The FCEd of shrimp in BG treatment was the highest and significantly higher than those in Y, G, B and GY treatments (P b 0.05). While the FCEd of shrimps showed no significant difference among Y, B and GY
Treatment
SGRd (%.day−1)
FId (%B.W.day−1)
FCEd (%)
Y G B GY BY BG
3.12 ± 0.12a 3.39 ± 0.02bc 3.12 ± 0.10a 3.29 ± 0.03ab 3.52 ± 0.05c 3.58 ± 0.03c
14.64 ± 0.36 14.32 ± 0.17 14.42 ± 0.42 15.12 ± 0.23 15.19 ± 0.21 14.56 ± 0.11
18.43 ± 0.95a 19.14 ± 0.26bc 18.13 ± 0.97a 18.73 ± 0.23ab 19.32 ± 0.39cd 20.37 ± 0.25d
Values (expressed as mean ± S.E., n = 4) with different letters in the same column are significantly different from each other (P b 0.05).
treatments (P N 0.05), the FCEd of shrimps in B treatment was significantly lower than those in G, BY and BG treatments (P b 0.05). 3.3. Energy allocation Significant differences in energy allocation of L. vannamei were observed under different light color regimes (P b 0.05). The energy allocation in the growth of shrimp in BG treatment was the highest and it was significantly higher than that in Y, B or GY treatment (P b 0.05).While the energy allocation in excretion of shrimp in BG treatment was the lowest and it was significantly lower than that in Y, G, B or GY treatment (P b 0.05). In contrast, the energy allocation in the growth of shrimp in B treatment was significantly lower than those in other regimes except for the Y treatment (P b 0.05), and the energy allocation in excretion of shrimp in the same group was significantly higher than those in other regimes (P b 0.05). There was no significant difference in energy allocation in respiration under different light color regimes (P N 0.05). The energy allocation in feces of shrimp in G treatment was significantly lower than those in other regimes (P b 0.05). No significant difference was detected in the energy allocation in feces among Y, GY, BY and BG treatments (P N 0.05), with each of which significantly higher than that in G or B treatment, (P b 0.05). A significant difference was also observed in energy allocation to molting under different light color regimes (P b 0.05), with a similar trend as of MF (Table 3). 3.4. Proximate body composition The moisture of shrimp in Y treatment was the highest, and was significantly higher than those in G, B, BY and BG treatments (P b 0.05). While the moisture of shrimp in BG treatment was significantly lower than those in Y and GY treatments (P b 0.05), no significant difference was detected when compared with other regimes (P N 0.05). There was no significant difference in crude protein content of shrimp among different regimes (P N 0.05). The crude lipid contents in G, B and GB treatments did not show any significant differences (P N 0.05). However, they appeared significantly higher than those in other regimes (P b 0.05). There was also no significant difference in crude lipid content of shrimp among Y, GY and BY treatments (P N 0.05). Ash content among three rhythmic fluctuating light color treatments did not have significantly differences from each other (P N 0.05), but they
Table 1 The growth and molting of L. vannamei in different light regimes. Treatment
Initial wet body weight(g)
Final wet body weight (g)
WG (%)
Survival rate (%)
MF (%.day−1)
Y G B GY BY BG
1.212 ± 0.008 1.214 ± 0.008 1.211 ± 0.006 1.210 ± 0.003 1.211 ± 0.003 1.213 ± 0.004
5.021 ± 0.202b 5.177 ± 0.084bc 4.590 ± 0.155a 5.329 ± 0.111bc 5.567 ± 0.166c 5.589 ± 0.115c
314.3 ± 17.5ab 326.7 ± 8.2bc 279.1 ± 12.9a 340.6 ± 9.8bc 359.9 ± 14.9c 360.7 ± 9.9c
90.0 ± 5.8 90.0 ± 5.8 95.0 ± 5.0 95.0 ± 5.0 90.0 ± 5.8 95.0 ± 5.0
5.05 ± 0.17ab 5.97 ± 0.15b 4.82 ± 0.32a 7.10 ± 0.48c 7.98 ± 0.42c 7.44 ± 0.31c
Values (expressed as mean ± S.E., n = 4) with different letters in the same column are significantly different from each other (P b 0.05).
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Table 3 Allocation of the consumed energy in L. vannamei at different light regimes.a Treatments
G/Cb (%)
R/Cc (%)
U/Cd (%)
F/Ce (%)
E/Cf (%)
Y G B GY BY BG
19.61 ± 0.91ab 21.50 ± 0.44cd 18.32 ± 0.41a 20.01 ± 0.26bc 21.09 ± 0.36bcd 22.57 ± 0.17d
59.01 ± 0.97 60.74 ± 0.50 59.64 ± 0.60 60.08 ± 0.43 59.59 ± 0.38 59.02 ± 0.39
4.96 ± 0.81b 4.45 ± 0.63b 7.54 ± 0.94c 3.76 ± 0.09ab 2.46 ± 0.37a 2.36 ± 0.48a
16.06 ± 0.37c 12.92 ± 0.29a 14.17 ± 0.32b 15.66 ± 0.31c 16.36 ± 0.27c 15.59 ± 0.17c
0.36 ± 0.01ab 0.39 ± 0.02b 0.33 ± 0.00a 0.49 ± 0.01c 0.50 ± 0.03c 0.46 ± 0.01c
a b c d e f
Values (expressed as mean ± S.E., n = 4) with different letters in the same column are significantly different from each other (P b 0.05). G/C (%) = energy for growth/energy consumed in food. R/C (%) = energy for respiration/energy consumed in food. U/C (%) = energy for excretion/energy consumed in food. F/C (%) = energy for feces/energy consumed in food. E/C (%) = energy for exuviate/energy consumed in food.
were significantly higher than those in constant light color treatments (P b 0.05). Among the three constant light color treatments, ash content in Y and B treatments was similar, and it was significantly lower than that in G treatment (P b 0.05) (Table 4). 4. Discussion Studies have shown that different species of crustacean have different sensitivity to light spectra (Chen et al., 1996; Xu et al., 2003). This could be highly related with various habitats of crustacean at different developmental stages (Forward and Gronin, 1979; FanjulMoles and Fuentes-Pardo, 1988; Fanjul-Moles et al., 1992). Moreover, the effects of different spectra on feed and growth of crustacean were different (Le Reste, 1970; Emmerson, et al., 1983; Xu et al., 2003; Wang et al., 2003). In our experiment, the growth of L. vannamei in G treatment was the best and the growth in B treatment was the worst among three constant light color treatments. This agrees quite well with the effect of light color on the growth of F. chinensis (Wang et al., 2003). Under the rhythmic fluctuating light color conditions, both WG and SGRd of shrimp in BY and BG treatments were significantly higher than those in the three constant light color treatments (P b 0.05). The environmental condition of natural pond could change due to the day and night alternation and the change of weather. The ingredients of spectra also differ with different aquifers (Jerlov, 1968) and the water turbidity value changes as well (Blaxter, 1968; McFarland, 1986). It is possible to suggest that in nature, L. vannamei undergoes the changes of spectra during its life cycle. Some researchers simulated the natural environmental fluctuations and found that the suitable fluctuation of environmental factor could promote the growth of crustacean (Tian et al., 2006; Mu et al., 2005; Din et al., 2008). In this study, we found that fluctuations from blue region of the spectra to green or yellow region could promote the growth of L. vannamei. Van Wormhoudt and Ceccaldi (1976) have shown that different wavelengths affect the enzymatic activity in Palaemon serratus shrimp, thus affecting digestibility, assimilation and the growth of shrimp. In our study, the FCEd of shrimps in B treatment was the Table 4 The proximate body composition of L. vannamei in different light regimes. Treatments
Moisture (%)
Crude protein (%)
Crude lipid (%)
Ash (%)
Y G B GY BY BG
77.84 ± 1.09a 75.78 ± 0.68bc 75.82 ± 0.52bc 76.93 ± 1.19ab 76.09 ± 0.52bc 75.55 ± 0.48c
15.96 ± 0.13a 17.32 ± 0.24b 17.74 ± 0.13c 16.57 ± 0.12d 17.26 ± 0.17b 17.70 ± 0.20c
2.80 ± 0.06a 3.00 ± 0.03b 3.00 ± 0.05b 2.81 ± 0.06a 2.85 ± 0.03a 3.02 ± 0.03b
2.90 ± 0.01a 2.95 ± 0.03b 2.89 ± 0.01a 2.98 ± 0.01c 2.99 ± 0.01c 2.95 ± 0.05c
Values (expressed as mean ± S.E., n = 4) with different letters in the same column are significantly different from each other (P b 0.05).
lowest and it was significantly lower than those in G, BY, and BG treatments (P b 0.05). This result suggests that the difference of growth of L. vannamei under different light color treatments might be related to FCEd of shrimp. Previous studies have also shown that metabolic energy accounts for the majority portion in the energy distribution of decapoda crustaceans. Therefore, the change of metabolic energy determined the energy accumulation in growth (Wang et al., 2005; Paul and Akira, 1989). In this study, the energy allocation in excretion under B treatment was about 1.5 times higher than those under BY and BG treatments, although no significant difference was detected in energy allocation in respiration under different light color regimes (P N 0.05). And the energy allocation in growth under the BY or BG treatment was higher than that under B treatment. The difference of energy distribution may be another reason for the variation in shrimp growth. In general, the growth curve of shrimp is similar to other crustaceans, i.e. a ladder-style with much fast growth during each molting process. After molting, the size of crustacean rarely increases until the next molting (Dall et al., 1990). Wang et al. (2004) suggested that the growth of shrimp was correlated to feed, digestion and absorption of food, while the molting was related with the secretion of hormone. So there may be two distinct regulations of these two physical activities. In this study, higher MF resulted in faster growth in shrimps; while for shrimps with poor growth, the MF was relatively low. Thus, there was a clear correlation between growth and molting. Huang (2003) found that shrimp can grow much faster with adequate feed supplies and good nutrition during molting. In our study, the shrimp were fed to satiation using high-quality artificial diet. Thus, the adequate feed supplies and good nutritional conditions were satisfied which might explain the clear correlation between growth and molting. Shearer (1994) indicated that the crude protein and ash level of fish body were mostly determined by endogenous factors (e.g., the size and the developmental stages). Instead, exogenously factors (e.g., temperature, salinity, and diet) did not show any effect on the crude protein level of fish body. In our study, a positive correlation was observed between ash level and the final body weight of shrimp. However, there was no correlation between the crude protein level and the final body weight of shrimps. For example, the size of shrimp in B treatment was the smallest, while the crude protein level was the highest. Miller and Weil (1963) suggested that change of one component of body composition might lead to a change in the content of other components. For instance, moisture difference in shrimps could influence the level of crude proteins. Studies in fish suggested that the lipid level increased with the decrease of moisture level, and the lipid level could be forecasted in use of body weight and moisture level (Spigarelli et al., 1982; Konstantinov and Zdanovich, 1986). Consistent with the results of fish research, the moisture
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level of shrimps in our study had a negative correlation with the corresponding lipid level. In conclusion, our study indicated that the rhythmic light color fluctuations affected the molting and growth of L. vannamei and the fluctuations from blue to green or yellow region of the spectra were beneficial to the growth of L. vannamei. Acknowledgments This work was supported by the Chinese National Natural Science Foundation (grant no. 30571441), the Key Project of Scientific and Technical Supporting Programs funded by Ministry of Science & Technology of China (grant no. 2006BAD09A07) and the project under the Major State Basic Research of China (grant no. 2009CB118706). References Blaxter, J.H.S., 1968. Visual thresholds and spectral sensitivity of herring larvae. J. Exp. Biol. 48, 39–53. Caillouet, C.W., 1973. Ovarian maturation induced by eyestalk ablation in pink shrimp Penaeus duorarum Burkenroad. In: Wault, J.W., Boudreaux, J., Jaspers, E. (Eds.), Proe, 3rd A. Meeting. Wil. Mariculture Soc. Louisiana State Univ, Baton Rouge, pp. 205–225. Chen, S.Q., Li, A.J., Wang, C., 1996. The structure and physiological functions of eyes in shrimp (Penaeus chinensis). Mar. Fish. Res. 17, 30–34. Dall, W., Hill, B.J., Rothlisberg, P.C., Sharples, D.J., 1990. The Biology of the Penaeidae. Academic Press, London, San Diego. Din, S., Wang, F., Guo, B., Li, X.S., 2008. Effects of salinity fluctuation on the molt, growth, and energy budget of juvenile Fenneropenaeus chinens. Chin. J. App. Ecol. 19, 419–423 (in Chinese with English abstract). Dong, Y.W., Dong, S.L., Tian, X.L., Wang, F., Zhang, M.Z., 2006. Effects of diel temperature fluctuations on growth, oxygen consumption and proximate body composition in the sea cucumber Apostichopus japonicus Selenka. Aquaculture 255, 514–521. Emmerson, W.D., Hayes, D.P., Ngonyame, M., 1983. Growth and maturation of Peaneus indicus under blue and green light. S. Afr. J. Zool. 18, 71–75. Fanjul-Moles, M.L., Fuentes-Pardo, B., 1988. Spectral sensitivity in the course of the ontogeny of the crayfish Procambarus clarckii. Comp. Biochem. Physiol. 91A, 61–66. Fanjul-Moles, M.L., Miranda-Anaya, M., Fuentes-Pardo, B., 1992. Effect of monochromatic light upon the ERG circadian rhythm during ontogeny in crayfish (Procambarus clarckii). Comp. Biochem. Physiol. 102A, 99–106. Forward, R.B., Gronin, T.W., 1979. Spectral sensitivity of larvae from intertidal crustaceans. J. Comp. Physiol. 133, 311–315. Hillier, A.G., 1984. Artificial conditions influencing the maturation and spawning of subadult Penaeus monodon (Fabricius). Aquaculture 36, 179–184. Huang, G.Q. 2003. The Research about Feeding Behavior and Physiological Ecology of Fenneropenaeus chinensi. PhD Thesis, Ocean university of Qingdao, China (in Chinese).
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