Xiangli Tian

The effect of light color on the growth of Chinese shrimp Fenneropenaeus chinensis

Abstract The specific growth rate (SGR) over 45 days of Fenneropenaeus chinensis shrimp with initial body weight of 1.979±0.036 g under different light color was as follows: natural>green>yellow>blue light. The SGR of shrimp under blue light was only 73.0% and 85.8% of those under natural light and green light, respectively. The maximal and minimal feed intake (FI) of the animal occurred under blue light and yellow light (difference 16.6%), respectively. The lowest food conversion efficiency (FCE) occurred in the blue light group (64.5% and 75.8% of that under natural and green light, respectively). FCE values between blue and natural light groups were significantly different ( P F. chinensis was relatively sensitive to blue light, under which the animal was active in feeding behavior, and gained a higher FI as well as a lower FCE, and therefore, a lower SGR.Shrimp may grow faster in the organically rich earthen ponds than in organically poor waters because there is less blue light spectrum in earthen ponds.

The Effect of Previous Feeding Regimes on the Compensatory Growth Response in Chinese Shrimp, Fenneropenaeus Chinensis

Abstract A 40-day feeding experiment was conducted to investigate the effect of previous food restriction on the compensatory growth response in Chinese shrimp, Fenneropenaeus chinensis. Four groups of shrimp with initial body weight of 2.189 ± 0.093 g (mean ± SE) were used, in which the control group (Group C) received ad libitum rations throughout the experiment, and the other three groups (expressed as Group R4, R8, and R12) were first fed at 4%, 8% and 12% of body weight per day (% B.W.·day−1), respectively, for 10 days and were then fed ad libitum for a recovery period of 30 days. After 10 days of restricted feeding, the shrimp showed increased body contents of moisture and ash and decreased contents of lipid, protein, and energy compared with the controls. The effect of previous food restriction on body biochemical composition gradually reversed during the period of ad libitum feeding. At last, there were no significant differences in body composition among all groups, with the exception of a higher...

Effects of dietary Bacillus cereus G19, B. cereus BC-01, and Paracoccus marcusii DB11 supplementation on the growth, immune response, and expression of immune-related genes in coelomocytes and intestine of the sea cucumber (Apostichopus japonicus Selenka)

Probiotics have positive effects on the nutrient digestibility and absorption, immune responses, and growth of aquatic animals, including the sea cucumber (Apostichopus japonicus Selenka). A 60-day feeding trial was conducted to evaluate the effects of Bacillus cereus G19, B. cereus BC-01 and Paracoccus marcusii DB11 supplementation on the growth, immune response, and expression level of four immune-related genes (Aj-p105, Aj-p50, Aj-rel, and Aj-lys) in coelomocytes and the intestine of juvenile sea cucumbers. One group was fed the basal diet (control group), while three other groups were fed the basal diet supplemented with B. cereus G19 (G19 group), B. cereus BC-01 (BC group), or P. marcusii DB11 (PM group). The growth rate of sea cucumbers fed diets with probiotics supplementation was significantly higher than that of the control group (P < 0.05). Sea cucumbers in the G19 and PM groups had a significantly greater phagocytic activity of coelomocytes compared to the control group (P < 0.05), while those in the G19 and BC groups had a greater respiratory burst activity (P < 0.05). The alkaline phosphatase (AKP) activity of coelomocytes in sea cucumbers fed diets with probiotics supplementation was significantly higher than the control group (P < 0.05). Comparatively, superoxide dismutase (SOD) activity of coelomocytes for sea cucumber in the PM group was significantly greater (P < 0.05). As for the immune-related genes, B. cereus G19 supplementation significantly increased the expression level of the Aj-rel gene in coelomocytes (P < 0.05), while B. cereus BC-01 supplementation significantly increased that of the Aj-p50 gene as compared to the control group (P < 0.05). In the intestine, the relative expression level of Aj-p105, Aj-p50, and Aj-lys genes in the PM group was significantly higher than that in the control group (P < 0.05). These results suggested that B. cereus G19 and B. cereus BC-01 supplementation could improve the growth performance and the immune response in coelomocytes, while P. marcusii DB11 supplementation could have a positive effect on the growth performance and immune response in coelomocytes and the intestine of sea cucumbers.

Ecological effects of co-culturing sea cucumber Apostichopus japonicus (Selenka) with scallop Chlamys farreri in earthen ponds

Monthly changes in sedimentation and sediment properties were studied for three different culture treatments: sea cucumber monoculture (Mc), sea cucumber and scallop polyculture (Ps-c) and scallop monoculture (Ms). Results indicated that the survival rate of sea cucumber was significantly higher in Ps-c cultures than in Mc cultures. Sea cucumber yield was 69.6% higher in Ps-c culture than in Mc culture. No significant differences in body weight and scallop shell length were found between Ps-c and Ms cultures. The mean sedimentation rate of total particulate matter (TPM) was 72.2 g/(m2·d) in Ps-c cultures, with a maximum of 119.7 g/(m2·d), which was markedly higher than that of Mc (mean value). Sedimentation rates of organic matter (OM), total organic carbon (TOC), total nitrogen (TN) and total phosphorus (TP) in Ps-c cultures were also significantly higher than those in Mc cultures. TOC and TN contents of sediment increased rapidly in the first 5 months in Ms cultures and remained at a high level. TOC and TN contents in Mc and Ps-c cultures decreased during sea cucumber feeding seasons and increased during sea cucumber dormancy periods (summer and winter). The study demonstrates that co-culture of sea cucumber and scallop in earthen ponds is an alternative way to alleviate nutrient loads and improve water quality in coastal aquaculture systems. Moreover, it provides the additional benefit of an increased sea cucumber yield.

Assessment of the role of brine shrimp Artemia in white spot syndrome virus (WSSV) transmission

Challenge tests with Artemia four different development stages (nauplii, metanauplii, pseudoadults and adults) to white spot syndrome virus was carried out by immersion challenge and virus-phytoplankton adhesion route in order to asses the possibility of Artemia acting as a vector of WSSV to penaeid shrimp Litopenaeus vannamei postlarvae. The WSSV succeeded in infecting four stages Artemia, and nested-PCR detection for WSSV revealed positive results to virus-phytoplankton adhesion route. No mass mortalities were observed in penaeid shrimp postlarvae fed with WSSV-positive Artemia which exposed to WSSV by virus-phytoplankton adhesion route, whereas WSSV DNA detected in penaeid shrimp postlarvae by nested-PCR. By contrary, no WSSV-positive was detected in any animal fed with WSSV-negative Artemia. These results indicated that Artemia could serve as a vector in WSSV transmission.

Effects of circadian rhythms of fluctuating temperature on growth and biochemical composition of Ulva pertusa

The marcoalga Ulva pertusa was cultured under (20 ± 2)°C, (20 ± 4)°C, (20 ± 6)°C, (20 ± 8)°C and (20 ± 10)°C circadian rhythms of fluctuating temperature conditions, and constant temperature of 20°C was used as the control. The growth rate of macroalga at (20 ± 2)°C, (20 ± 4)°C and (20 ± 6)°C were significantly higher than that at constant temperature of 20°C, while growth rate at (20 ± 8)°C and (20 ± 10)°C were significantly lower than that at constant temperature of 20°C. The growth rate of macroalga was a quadratic function of the thermal amplitude. Such a growth model can be described by G = β0 + β1(TA) + β2(TA)2, where G represents the relative growth rate, TA is thermal amplitude in degree Celsius, β0 is the intercept on the G axis, and β1 and β2 are the regression coefficients. The optimal thermal amplitude for the growth of thallus at mean temperature of 20°C was estimated to be ± 3.69°C. Analysis of biochemical composition at the final stages of thaulls growth revealed that diel fluctuating temperature caused various influences (P < 0.05). The content of chlorophyll, protein and total solute carbohydrate at (20 ± 2)°C and (20 ± 4)°C were slightly higher than those at constant temperature of 20°C, however no statistically significant differences were found among them (P > 0.05). While osmolytes (total solute carbohydrate and free proline) at (20 ± 10)°C were significantly higher than that at 20°C (P < 0.05). Therefore, more chlorophyll and carbohydrate production might account for the enhancement in the growth of macroalga at the diel fluctuating temperatures in the present study.

THE GROWTH OF JUVENILE CHINESE SHRIMP, FENNEROPENAEUS CHINENSIS OSBECK, AT CONSTANT AND DIEL FLUCTUATING TEMPERATURES

Abstract The growth, food consumption, food conversion efficiency and apparent digestibility coefficient of juvenile Chinese shrimp, Fenneropenaeus chinensis Osbeck (body weight 0.36 ± 0.04 g) were examined under different temperature regimes. The animals were subjected to 6 constant temperatures of 18°C, 22°C, 25°C, 28°C, 31°C and 34°C and diel fluctuating temperatures of 22 ± 2°C, 25 ± 2°C, 28 ± 2°C and 31 ± 2°C. The results showed that the growth rate of Chinese shrimp at the constant temperature regimes increased from 18°C to 31°C, whereas decreased significantly at 34°C. The growth rates of shrimp at 22 ± 2°C, 25 ± 2°C and 28 ± 2°C were significantly greater than those at the corresponding constant temperatures of 22°C, 25°C and 28°C, respectively, whereas no significant difference was found between 31 ± 2°C and 31°C. As compared with those at constant temperature, the mean temperature at which maximum growth rate of shrimp occurred shifted to cooler temperature at diel fluctuating temperatures. The shrimp consumed more food at 25 ± 2°C, 28 ± 2°C and 31 ± 2°C than those at 25°C, 28°C and 31°CC, respectively, but no significant difference in apparent digestibility coefficient was found between the fluctuating and corresponding constant temperatures. The food conversion efficiency and energy assimilated into growth as percentage of energy from food for shrimp at 22 ± 2°C, 25 ± 2°C and 28 ± 2°C were significantly higher than at the corresponding constant temperatures. Therefore, more food consumption, high food conversion efficiency and more energy partitioned into growth might contribute to the enhanced growth rate at the fluctuating temperatures.

Intestinal microbiota and immune related genes in sea cucumber (Apostichopus japonicus) response to dietary β-glucan supplementation

β-glucan is a prebiotic well known for its beneficial outcomes on sea cucumber health through modifying the host intestinal microbiota. High-throughput sequencing techniques provide an opportunity for the identification and characterization of microbes. In this study, we investigated the intestinal microbial community composition, interaction among species, and intestinal immune genes in sea cucumber fed with diet supplemented with or without β-glucan supplementation. The results show that the intestinal dominant classes in the control group are Flavobacteriia, Gammaproteobacteria, and Alphaproteobacteria, whereas Alphaproteobacteria, Flavobacteriia, and Verrucomicrobiae are enriched in the β-glucan group. Dietary β-glucan supplementation promoted the proliferation of the family Rhodobacteraceae of the Alphaproteobacteria class and the family Verrucomicrobiaceae of the Verrucomicrobiae class and reduced the relative abundance of the family Flavobacteriaceae of Flavobacteria class. The ecological network analysis suggests that dietary β-glucan supplementation can alter the network interactions among different microbial functional groups by changing the microbial community composition and topological roles of the OTUs in the ecological network. Dietary β-glucan supplementation has a positive impact on immune responses of the intestine of sea cucumber by activating NF-κB signaling pathway, probably through modulating the balance of intestinal microbiota.

Effect of Bacillus baekryungensis YD13 supplemented in diets on growth performance and immune response of sea cucumber (Apostichopus japonicus)

The effect of a potential probiotic on the growth performance and immune response of sea cucumber (Apostichopus japonicus) was investigated. Bacillus baekryungensis YD13 isolated from sea cucumber culturing ponds was added to sea cucumber basal feed as a probiotic in different doses (0, the control; 1×104 (YD134), 1×106 (YD136) and 1×108 (YD138) CFU g−1 of diet), and administered orally to A. japonicus (initial mean wet weight 5.44 g ± 0.17 g). The sea cucumbers were fed in 20 aquaria, 5 each treatment, for 60 d. At the end of growth trial, 20 sea cucumbers from each treatment were challenged with Vibrio splendidus. A. japonicus in YD134 and YD136 exhibited significantly better growth performance than control (P < 0.05). Five non-specific immune parameters including lysozyme, acid phosphatase, alkaline phosphatase, superoxide dismutase and catalase in coelomic fluid were measured to evaluate the immune response of A. japonicus to the probiotics. Results showed that all parameters were significantly improved when YD11 was supplemented in the dose of 1×106 CFU g−1 (P < 0.05). The cumulative incidence and mortality after the Vibrio splendidus challenge decreased significantly in sea cucumbers of YD136. Accordingly, 1×106 CFU g−1 of YD13 in diet was recommended for the growth promotion and immune enhancement of A. japonicus.

Molecular ecological network analysis reveals the effects of probiotics and florfenicol on intestinal microbiota homeostasis: An example of sea cucumber

Animal gut harbors diverse microbes that play crucial roles in the nutrition uptake, metabolism, and the regulation of host immune responses. The intestinal microbiota homeostasis is critical for health but poorly understood. Probiotics Paracoccus marcusii DB11 and Bacillus cereus G19, and antibiotics florfenicol did not significantly impact species richness and the diversity of intestinal microbiota of sea cucumber, in comparison with those in the control group by high-throughput sequencing. Molecular ecological network analysis indicated that P. marcusii DB11 supplementation may lead to sub-module integration and the formation of a large, new sub-module, and enhance species-species interactions and connecter and module hub numbers. B. cereus G19 supplementation decreased sub-module numbers, and increased the number of species-species interactions and module hubs. Sea cucumber treated with florfenicol were shown to have only one connecter and the lowest number of operational taxonomic units (OTUs) and species-species interactions within the ecological network. These results suggested that P. marcusii DB11 or B. cereus G19 may promote intestinal microbiota homeostasis by improving modularity, enhancing species-species interactions and increasing the number of connecters and/or module hubs within the network. In contrast, the use of florfenicol can lead to homeostatic collapse through the deterioration of the ecological network.