Chinensis Juveniles Research Articles

Evaluation of genetic parameters for growth and cold tolerance traits in Fenneropenaeus chinensis juveniles.

In this study, genetic parameters were obtained for growth and cold tolerance of 99 Fenneropenaeus chinensis juvenile families by means of indoor artificial cooling (starting from 14°C, 2°C/d). A linear mixed model was fitted to estimate variance components using the ASReml software package. Heritabilities estimated for body weight (BW) and body length (BL) of F. chinensis juveniles were 0.078 ± 0.124 and 0.131 ± 0.133, respectively. The estimates of heritability were low in magnitude for both traits. The differences between the heritabilities estimated for the two growth traits were not significant with each other, and the heritabilities were not significantly different from zero (P > 0.05). The phenotypic and genetic correlation coefficients between BW and BL were as high as 0.9408 ± 0.0040 and 0.9562 ± 0.0551, respectively, and both were significantly different from zero (P < 0.01). The heritabilities of temperature at death (TAD) and cooling degree hours (CDH) were 0.265 ± 0.091 and 0.077 ± 0.058, respectively. The heritability estimates for TAD was moderate and significantly different from zero (P < 0.01). The correlation analysis indicated that the phenotypic correlation coefficient between TAD and CDH was -0.5470 ± 0.0174, and the genetic correlation coefficient was -0.6707 ± 0.3635. In the analysis of growth traits and cold tolerance traits, the values of phenotypic correlation coefficient were floating between -0.1055 and 0.1098, both were significantly different from zero (P < 0.05), while the genetic correlation had a larger range (0.0526 ~ 0.9914), and all were not significantly different from zero (P > 0.05). In this study, there was a low correlation between growth and cold tolerance traits, indicating that growth traits and cold tolerance traits should be considered collectively in the breeding program of shrimp.

Effect of refeeding on the growth and digestive enzyme activities of Fenneropenaeus chinensis juveniles exposed to different periods of food deprivation

The changes in the specific growth rate (SGR), feed intake (FI), feed conversion efficiency (FCE), and digestive enzyme activities (protease, amylase, and lipase in the hepatopancreas) of Fenneropenaeus chinensis juveniles (0.753 ± 0.041 g, wet weight) exposed to different periods of food deprivation were investigated during the period of refeeding in a controlled laboratory experiment. The starvation-refeeding cycles consisted of the following seven regimes of 24-day duration: satiate feeding (control, SC); no feeding for 4 (S4), 8 (S8), 12 (S12), 16 (S16), 20 (S20), and 24 (S24) days; then feeding to apparent satiation for the next 20, 16, 12, 8, 4, and 0 days, respectively. The various starvation-refeeding cycles have significant influences on the growth of the test shrimps. The SGR of the shrimps exposed to S4 and S8 treatments exceeded the controls, and no significant differences in SGR (P > 0.05) were found between the SC and S12 or S16 treatments at the end of the refeeding. These changes may have resulted from the significant increase in FI and FCE. The protease activities of test shrimps exposed to different periods of food deprivation were significantly lower (P < 0.05) than those of shrimps under SC treatment at the end of food deprivation then showed a tendency to rapidly increase during refeeding. However, nearly the exact opposite occurred for amylase activities and lipase activities. Lipid and carbohydrate reserves in the hepatopancreas are preferentially mobilized with protein-sparing effect at the beginning of food deprivation. Proteins are the main nutritional store during the refeeding. The findings of the research will be beneficial in the design of feeding regimes and will improve our knowledge on some aspects of the nutrition physiology of F. chinensis related to their biology.

Starvation resistance and metabolic response to food deprivation and recovery feeding in Fenneropenaeus chinensis juveniles

Starvation resistance in the juveniles of Chinese shrimp, Fenneropenaeus chinensis Osbeck, was studied by point-of-no-return (PNR) and point-of-reserve-saturation (PRS) experiments. Changes in oxygen consumption rate, ammonia-N excretion rate, and oxygen consumed to nitrogen excreted (O:N) ratio were investigated immediately before and after the period of recovery feeding for each regime to assess metabolic response during starvation and refeeding. There was a significant change in survival rate and wet weight of test shrimp throughout the PNR and PRS experiments (P < 0.05). The estimated PNR and PRS for F. chinensis juveniles could be directly calculated from the selected equations as PNR50 = 7.86 days, PNR100 = 21.42 days, PRS0 = 1.16 days, and PRS50 = 11.75 days. A decrease in metabolic rate during starvation as a means of conserving energy was found in F. chinensis juveniles. Furthermore, although F. chinensis juveniles only utilized protein as an energy source during starvation, they showed a shift from pure protein during starvation to an equal utilization of protein and lipid or a lipid-carbohydrate mixture during later satiate feeding. The results in the present study indicate that F. chinensis juveniles have the ability to withstand and recover from relatively prolonged starvation after longer initial feeding periods. The knowledge derived from the understanding of starvation resistance and the corresponding metabolic response of F. chinensis juveniles will be useful in the design of feeding regimes in this species.

Protection of shrimp ( Penaeus chinensis) against white spot syndrome virus (WSSV) challenge by double-stranded RNA

To determine whether Penaeus chinensis can be protected against white spot syndrome virus (WSSV) infection by intramuscular injection with long double-stranded RNAs (dsRNAs) as in other shrimp species and whether the protection degree by WSSV-specific dsRNAs is correlated with the roles of viral genes, P. chinensis juveniles were intramuscularly injected with long dsRNAs corresponding to VP28, VP281, protein kinase genes of WSSV, and an unrelated long dsRNA corresponding to a green fluorescence protein (GFP) gene. All shrimp injected with long dsRNAs including GFP dsRNA showed higher survival rates against WSSV infection than shrimp injected with PBS alone. Furthermore, shrimp injected with dsRNAs corresponding to VP28 and protein kinase showed higher survival rates than those injected with dsRNAs corresponding to VP281 and GFP. These results indicate that the introduction of long dsRNAs corresponding to viral proteins, which are essential for WSSV infection, is quite effective in blocking WSSV infection in P. chinensis, and suggest that dsRNA-mediated protection is a common feature across shrimp species.

Effects of pH on survival, phosphorus concentration, adenylate energy charge and Na +–K + ATPase activities of Penaeus chinensis Osbeck juveniles

Penaeus chinensis (Osbeck) juveniles were maintained for 14 days at pH 6.0, 7.0, 7.6, 8.0 and 8.5, respectively. The effects of pH on survival, phosphorus concentration, adenylate energy charge (AEC) and Na +–K + adenosine triphosphatase (ATPase) activities of prawns were investigated. The results showed that survival of P. chinensis was impaired at low and high pH levels. The total phosphate level and AEC in abdominal muscle increased with pH level in range of 6.0–7.6 reaching the maximum values at pH 7.6. Thereafter, the levels declined with increasing pH level in range of 7.6–8.5. The change of Na +–K + ATPase activity in gill of prawn was similar to that of total phosphorus content and AEC in muscle of prawn at different pH. The effect of pH on Na +–K + ATPase activity in the muscle was lower than on that in gill.

Osmotic concentration and tissue water of Penaeus chinensis juveniles reared at different salinity and temperature levels

Penaeus chinensis juveniles were reared for 50 days at 16 combinations of salinity (10, 20, 30 and 40 ppt) and temperature levels (12, 18, 24 and 30°C). All shrimps survived at 20 ppt and 18°C, whereas no shrimp survived at 10 ppt and 12°C after 30 days. Tissue water was inversely related to salinity at all temperatures tested. The isosmotic points computed from the linear relationship between hemolymph osmolality and medium osmolality were 736, 698, 674 and 667 mOsm/kg which are equivalent to 27.4, 26.1, 25.3 and 25.0 ppt at 12, 18, 24 and 30°C, respectively.

Survival, growth and intermolt period of juvenile Penaeus chinensis (Osbeck) reared at different combinations of salinity and temperature

Penaeus chinensis (Osbeck) juveniles (0.23–0.36 g) were reared at 16 combinations of salinity (10, 20, 30 and 40 ppt) and temperature (12 °, 18 °, 24 ° and 30 °C) for 50 days. All shrimp survived at 20 ppt and 18 °C, whereas no shrimp survived at 10 ppt and 12 °C after 30 days. Animals at 20 and 30 ppt and at 30 °C grew significantly faster ( P < 0.05) than those at 30 and 40 ppt at 24 °C, and at 40 ppt and 30 °C. The intermolt period of shrimp was 21.5–28.5 days, 10.8–14.4 days, 8.0–8.9 days and 7.4–8.5 days at 12 °, 18 °, 24 ° and 30 °C, respectively. Best growth of juvenile P. chinensis was achieved over the range 20–30 ppt at 30 °C.

Responses of oxygen consumption, Ammonia-N excretion and Urea-N excretion of Penaeus chinensis exposed to ambient ammonia at different salinity and pH levels

Oxygen consumption (O 2 mg g −1 h −1) of Penaeus chinensis juveniles (0.76 ± 0.05 g) increased with increased concentration of ambient ammonia-N in the range of 0–10 mg 1 −1, but decreased with increased salinity level in the range of 10–30 p.s.u. (practical salinity units) and pH level in the range of 7.0–8.5. Urea-N excretion and nitrite-N excretion of shrimp increased with increased salinity, pH and ambient ammonia-N levels. Whereas, ammonia-N excretion of shrimp decreased with increased salinity, pH and ambient ammonia-N levels. Ammonia-N uptake occurred when shrimp were exposed to ambient ammonia-N at 5 mg 1 −1 or greater at every salinity and pH level tested. Shrimp at an increased salinity level, and at an increased concentration of ambient ammonia-N enhanced their urea-N excretion, an effect that was more pronounced at high pH than at low pH.

Survival, haemolymph osmolality and tissue water of Penaeus chinensis juveniles acclimated to different salinity and temperature levels

Abstract Survival, growth, haemolymph osmolality and tissue water of Penaeus chinensis (Osbeck) juveniles (0.11 ± 0.04 g) were investigated, after they were acclimated to 10, 20, 30 and 40 ppt from 33 ppt for 14 days at 24°C, and then acclimated to 12, 18, 24 and 30°C at each salinity for 14 days. The survival of shrimp was the lowest at 10 ppt and 12°C. Growth of shrimp increased with increased temperature in the range 12–24°C, with no significant difference among four salinity levels at 18, 24 and 30°C. Haemolymph osmolality increased with increased salinity, and decreased with increased temperature. The isosmotic point computed from the linear relationship between haemolymph osmolality and medium osmolality was 664, 632, 629 and 602 mOsm/kg which is equivalent to 25.2, 24.1, 24.0 and 23.1 ppt at 12, 18, 24 and 30°C, respectively. Tissue water decreased with increased medium osmolality and haemolymph osmolality. The slope obtained from the relationship between haemolymph osmolality and medium osmolality indicated that there is an impairment of osmoregulatory ability for the P. chinensis juveniles at 12°C.

Oxygen Consumption and Ammonia-n eXcretion of Penaeus Chinensis (Osbeck, 1765) Juveniles At Different Salinity Levels (Decapoda, Penaeidae)

[Oxygen consumption (O2mg/g/h) of Penaeus chinensis (Osbeck, 1765) juveniles (0.078 ± 0.011 g) appeared to increase with increase of salinity over the range of 15, 20, 25 and 30 ppt, while ammonia-N excretion (mg/g/h) displayed an inverse relationship with salinity. Both oxygen consumption and ammonia-N excretion of prawns in 25 and 30 ppt was relatively stable. However, prawns at low salinity (15 and 20 ppt) consumed less oxygen and excreted more ammonia-N. It is suggested that catabolism of amino acid is required to reduce the internal osmolality of prawns which utilize amino acid as fuel to provide the necessary energy for hypo-regulation of P. chinensis., Oxygen consumption (O2mg/g/h) of Penaeus chinensis (Osbeck, 1765) juveniles (0.078 ± 0.011 g) appeared to increase with increase of salinity over the range of 15, 20, 25 and 30 ppt, while ammonia-N excretion (mg/g/h) displayed an inverse relationship with salinity. Both oxygen consumption and ammonia-N excretion of prawns in 25 and 30 ppt was relatively stable. However, prawns at low salinity (15 and 20 ppt) consumed less oxygen and excreted more ammonia-N. It is suggested that catabolism of amino acid is required to reduce the internal osmolality of prawns which utilize amino acid as fuel to provide the necessary energy for hypo-regulation of P. chinensis.]

Responses of hemolymph osmolality and tissue water of Penaeus chinensis Osbeck juveniles subjected to sudden change in salinity

Hemolymph osmolality and tissue water of laboratory-reared Penaeus chinensis Osbeck juveniles (0.83 to 1.86 g) were investigated, after they had been transferred individually from 10, 20, 30 and 40 ppt to 10, 20, 30 and 40 ppt for 0.25, 0.5, 1, 2, 5 and 10 d, respectively. Hemolymph osmolality and tissue water of shrimp were stablilized within 5 d after they had been subjected to a sudden change in salinity from each salinity level. Hemolymph osmolality had a positively linear relationship with medium osmolality. Tissue water decreased with increased medium osmolality, and decreased with increased hemolymph osmolality. The mean (SD) isosmotic point was 703 (8) mOsm kg−1 which is equivalent to 24.2 (1.0) ppt. P. chinensis juveniles exhibited hyperosmotic regulation in salinities below isosmotic value, and hypoosmotic regulation in those above. The shrimp originally adapted to high salinity levels (30 and 40 ppt) showed less fluctuation of tissue water than those adapted to low salinity levels (10 and 20 ppt) when they were subjected to a sudden change in salinity.

Effect of salinity on growth of Penaeus chinensis juveniles

1. 1. Survival of Penaeus chinensis juveniles (0.92 ± 0.11 g) acclimated from 32 ppt seawater to 0 and 30 ppt seawater in 5 ppt intervals per day was 0 and 100% after 12 and 14 days, respectively. 2. 2. Survival was 75, 88 and 76% for the shrimps reared in 20, 25 and 30 ppt after 60 days. 3. 3. Molting frequency was lowest for the shrimps reared at 20 ppt, and highest for those reared at 5 and 40 ppt. 4. 4. Hemolymph osmolality had a linear relationship (slope = 0.189) with external osmolality over the salinity range of 5 and 40 ppt. 5. 5. The isosmotic point was 480mOsm/kg which is equivalent to 16.5 ppt. 6. 6. P. chinensis juveniles in the isosmotic environment or slightly higher grew the best, those in the hyperosmotic environment the second, and those in the hypoosmotic environment grew the worst.

Oxygen consumption and ammonia-N excretion of Penaeus chinensis juveniles exposed to ambient ammonia at different salinity levels

1. 1. Oxygen consumption rate (O 2 mg/g/hr and ammonia-N (un-ionized plus ionized ammonia as nitrogen) excretion rate smg/g/hr of Penaeus chinensis juveniles (0.54 ± 0.11 g) decreased with increase of salinity among 10, 20 and 30 ppt. 2. 2. Oxygen consumption rate increased with increase of ambient ammonia-N at three salinity levels. 3. 3. Ammonia-N excretion rate was highest (204 smg/g/hr in P. chinensis exposed to 0.985 mg/l ammonia-N at 10 ppt, and lowest (−416 smg/g/hr in that exposed to 9.897 mg/l ammonia-N at 30 ppt. 4. 4. In the prawns exposed to 9.921 mg/1 ammonia-N at 20 ppt, and to 5.087 and 9.897 mg/l ammonia-N at 30 ppt, ammonia-N excretion was heavily depressed and ammonia-N influx occurred (ammonia-N uptake was much higher than ammonia-N excretion).

Lethal effects of ammonia on Penaeus chinensis Osbeck juveniles at different salinity levels

Penaeus chinensis Osbeck juveniles (3.61± 0.23 cm) were exposed to different concentrations of ammonia, using the static renewal method, in different salinity levels at pH 8.12 and 25 ° C. The 24, 48, 96 and 120-h LC 50 value of ammonia-N (un-ionized plus ionized ammonia as nitrogen) on P. chinensis juveniles was 66.73, 53.94, 42.44 and 39.87 mg · 1 −1 at 30%; 52.20, 42.65, 38.87 and 37.83 mg · 1 −1 at 20%; and 44.02, 34.77, 28.18 and 24.34 mg · 1 −1 at 10%. The 24, 48, 96 and 120-h LC 50 value of NH′ 3-N (un-ionized ammonia as nitrogen) was 3.88, 3.13, 2.47 and 2.32 mg · 1 −1 at 30%; 3.31, 2.70, 2.46 and 2.40 mg · 1 −1 at 20%; and 3.03, 2.39, 1.94 and 1.68 mg · 1 −1 at 10%, respectively. As the salinity decreased from 30 to 10%, susceptibility increased 154% for ammonia-N and 130% for NH 3-N. The “threshold” was found at 144 h, and the “incipient LC 50” for P. chinensis juveniles was 38.12, 36.01 and 22.77 mg · 1 −1 for ammonia-N (2.21, 2.28 and 1.57 mg · 1 −1 for NH 3-N). The “safety level” for rearing P. chinensis juveniles was estimated to be 3.81, 3.60 and 2.23 mg · 1 −1 for ammonia-N (0.22, 0.22 and 0.16 mg · 1 −1 for NH 3-N) in 30, 20 and 10%, respectively.

Effects of temperature, salinity and ambient ammonia on lethal dissolved oxygen of Penaeus chinensis juveniles

1. Lethal DO (dissolved oxygen) for Penaeus chinensis weights from 0.31 to 10.54g was 0.74 ± 0.03 mg/l in average. However, lethal time (hr) had an exponential relationship with weight. 2. Lethal DO was the highest at 35°C and the lowest at 25°C for P. chinensis juveniles exposed to 30 ppt at 15, 25 and 35°C. Lethal time (hr) was the shortest at 35°C and the longest at 25°C. 3. Lethal DO was the highest in 15 ppt and the lowest in 30 ppt among those exposed to 15, 20, 25, 30 ppt seawater at 25°C. No significant difference ( P > 0.05) of lethal time was found among four salinity levels. 4. Lethal DO increased, and lethal time decreased with increase of ambient ammonia- N in the range of 0.02 to 5.33 mg/l. Both lethal DO and lethal time of shrimps exposed to higher than 1.07 mg/l ammonia- N were significantly different ( P < 0.05) to those exposed to control (0.02 mg/l ammonia- N).

Oxygen consumption and ammonia-N excretion of prawns (Penaeus chinensis) exposed to ambient ammonia

Both oxygen consumption and ammonia-N excretion ofPenaeus chinensis had a negative power regression with body weight. WhenP. chinensis juveniles (0.079+-0.004 g) were subjected to increased ambient ammonia-N (un-ionized plus ionized ammonia as nitrogen) in the range of 0.015–5.529 mg/L at 25°C and pH 7.93–8.24, oxygen consumption (O2 mg/g/h) and ammonia-N excretion (mg/g/h) increased. Oxygen consumption and ammonia-N excretion of the shrimps exposed to control (0.015 mg/L) and 5.529 mg/L ammonia-N was 0.858 to 1.628, 1.159 to 2.675 O2 mg/g/h and 0.028 to 0.049 and 0.942 to 2.004 ammonia-N mg/g/h, respectively. Both oxygen consumption and ammonia-N excretion of the shrimp had a linear correlation after 6, 10, and 14 h; and had a power correlation after 20 h with ambient ammonia-N in the range of 0.015–5.529 mg/L. Mean cumulative amount of dissolved oxygen consumed in 20 h was 1.518, 1.786, 1.897, 2.085, 2.193, 2.322, and 2.526 mg; and a mean cumulative amount of excreted ammonia-N in 20 h was 0.059, 0.501, 0.671, 0.792, 1.527, 1.780, and 1.964 mg for individualP. chinensis exposed to 0.015, 0.618, 1.182, 2.112, 2.876, 4.381, and 5.529 mg/L ammonia-N, respectively.

Lethal effects of ammonia and nitrite onPenaeus chinensis juveniles

Juveniles of the prawnPenaeus chinensis (3.96 ±0.18 cm, 0.36±0.06 g) reared in Taiwan in 1989 were exposed to different concentrations of ammonia and nitrite, by a static renewal method in 33‰ seawater at pH 7.94 and at 26 °C. The 24, 48, 96 and 120 h LC50 (median lethal concentration) of ammonia were 3.29, 2.10, 1.53 and 1.44 mg l−1 for NH3-N (un-ionized ammonia as nitrogen) and 79.97, 51.14, 37.00 and 35.09 mg l−1 for ammonia-N (un-ionized plus ionized ammonia as nitrogen). The 24, 96, 120, 144 and 192 h LC50 of nitrite-N were 339, 37.71, 29.18, 26.98 and 22.95 mg l−1. The LC50 decreased with increasing exposure time. During the first 96 h,P. chinesis juveniles were more susceptible to ammonia than nitrite. However, prawns were less tolerant to nitrite than ammonia when exposed for more than 96 h. The “threshold” was found at 120 and 192 h for ammonia and nitrite, respectively, on the toxicity curves. “Incipient LC50” was 1.44 mg l−1 for NH3-N, 35.09 mg l−1 for ammonia-N and 22.95 mg l−1 for nitrite-N. The “safe value” forP. chinensis juveniles was 0.14, 3.51 and 2.30 mg l−1, respectively.