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The experiment simulated the logistical transportation of Penaeus monodon. It set four distinct gradient Vitamin C (Vc) addition levels, including 0mg/L, 111mg/L, 222mg/L, and 333mg/L, to investigate the impact of Vc on the anti-stress ability of P. monodon during transportation. And the survival rate following transportation and a 15-day interim rearing period were recorded. Moreover, the alterations in tissue structure and activity of the enzymes alkaline phosphatase (ACP), alkaline phosphatase (AKP), total superoxide dismutase (T-SOD), and total superoxide dismutase (T-AOC) were checked. The results showed that with the increase of Vc supplemental level, the survival rate of P. monodon after transportation and after 15 days of temporary rearing increased to varying degrees. ACP and AKP in the hepatopancreas increased first and then decreased. T-SOD activity in the 0mg/L group was the lowest and then decreased gradually. The activity of total antioxidant capacity (T-AOC) in the 0mg/L group was the lowest and then stabilized. The branchial tissue structure also changed. The branchial tissue blood cell disorder decreased, the diaphragm gradually narrowed, the cornered cortex gradually recovered, and the swelling decreased. In conclusion, Vc positively affects the survival rate of P. monodon after transportation and temporary cultivation and alleviates the stress of P. monodon. The amount of Vc added at about 333mg/Lin, the transportation of P. monodon could play a positive role. The experimental results provide primary data for the transportation of P. monodon.

A novel TRY homolog was cloned in Penaeus monodon by RACE technology, named PmTry (GenBank: KP998480). The PmTry cDNA was 916 bp, which encodes 266 amino acids with a predicted molecular weight of 28.38 KDa and an isoelectric point of 4.58. Homologous analysis indicated that PmTry shared 42%~91% similarity with other species. The phylogenetic tree showed that PmTry was closely related to Fenneropenaeus chinensis. Tissue expression profiles showed that PmTry was highest expressed in the hepatopancreas and the lowest expressed in the eyestalk nerve. It was expressed in the whole growth stage of P. monodon, but the relative expression level of each stage was significantly different. In addition, PmTry-524 and PmTry-798 were particularly related to growth traits of P. monodon by genotype. The SNP markers may provide a basis for genetic selection and breed improvement studies in P. monodon.

Metapenaeus affinis is a crustacean with important commercial value in the fishery of the South China Sea. Overfishing has resulted in the decline of the wild population and germplasm degradation. However, there is little background knowledge about its gonadal development, and there is a lack of research on the development of this species. To better understand the molecular regulatory mechanisms during gonadal development, here, we performed RNA-Seq on immature and mature ovaries and compared their transcriptomic signatures. 126,930,488 and 122,677,356 clean sequencing reads were obtained from the Illumina sequencing platform, respectively. 394 differentially expressed genes (DEGs) were identified, of which 136 were up-regulated, and 258 were down-regulated. Further analysis revealed rich transcriptional sequences, which have homology with genes related to reproduction and development. Expression patterns of COX, GPX, E3s, PCNA, STPK, and other genes were changed during ovarian development. Validation by qRT-PCR demonstrated the reliability of RNA-Seq. This study has made a significant contribution to the currently available sequence data of M. affinis and provided reference data for the development of genetic and breeding work.

The fertilized eggs of "Nanhai 2" Penaeus monodon bred by our research group were incubated at the same temperature (30℃), different salinity (20, 25, 30, 35, 40), different pH (7.0, 7.5, 8.0, 8.5, 9.0) and different alkalinity (2.0 mmol/L, 2.5 mmol/L, 3.0 mmol/L, 3.5 mmol/L, 4.0 mmol/L) to explore the effects of salinity, pH and alkalinity on hatching rate of fertilized eggs of P. monodon. The results showed that the hatching rate of fertilization rate of P. monodon was closely related to salinity, and the best hatching rate was obtained when the seawater salinity was 30 with the average hatching rate was 82.60%. The hatching rate was very low when the salinity was as low as 20 or as high as 40, which was significantly lower than that of other treatments (P<0.05). The hatching effect of the fertilized eggs of P. monodon was closely related to the pH value of seawater, and the slightly alkaline seawater was conducive to the normal development of the fertilized eggs. Among them, the hatching effect of the seawater pH value of 8.0 was the best, and the average hatching rate of the fertilized eggs was 80.62%. Too low or too high pH value of the seawater was not conducive to the development of the embryo, and the hatching rate of the fertilized eggs decreased in varying degrees. There was no significant correlation between the hatching effect of fertilized eggs and the change of seawater alkalinity. The average hatching rate of fertilized eggs ranged from 78.65% to 83.12% in the alkalinity range of 2.0-4.0 mmol/L.

This study examined the growth response of black tiger shrimp, Penaeus monodon, reared in indoor cement ponds fed at variable daily feeding frequencies. Five hundred healthy shrimp (1.26±0.37 g initial weight) were stocked in 12 cement ponds (5.5×2.5×1.5m). Three ponds in each group were assigned to four different feeding frequency i.e., two, three, four and six times/day designated as FF1, FF2, FF3 and FF4, respectively. Artificial diet (40% fishmeal protein) was used to feed at eight percent of total shrimp body weight per day for a total period of 56 days. The shrimp length and weight were measured fortnightly and the feeding rate was adjusted according to the new weight. At the end of the trial, all shrimp remained healthy and active with the survival rate of 70-85%. The specific growth rate (SGR) were the highest in groups FF3 (4.21±0.53) and FF4 (4.23±1.04), which were significantly higher than those in FF1 (3.82±0.49) and FF2 (4.02±1.03) groups. Whole body proximate composition (protein, ash, moisture and lipid) remained similar in all the treatment groups. It could be concluded that the black tiger shrimp, P. monodon, would be grown in indoor cement ponds effectively by feeding four times day-1 to achieve significantly better growth.

To explore the effect of concentrated dephenolic cottonseed protein (CDCP) partly instead of fish meal on the non-specific immune of Penaeus monodon, we designed a single factor test to study the four types of non-specific immunity of P. monodon hepatopancreas after acute salinity stress. A total number of 5,400 P. monodon were selected with an initial body weight of 1.76±0.15g and randomly divide into 6 groups (3 replicates per group, 900 tails per replicate). Shrimp were feed with two protein level diets (Diet A and Diet B). After 8 weeks of feeding, P. monodon were randomly selected with an average weight of 14.71±1.06g in each feed group, and subjected to acute salinity stress of 10ppt and 20ppt after temporary rearing, and the heat shock protein 70 (HSP70), Na+-K+-ATPase, cortisol and the content of alkaline phosphatase (ALP) were measured. The results of the study showed that when the CDCP partially replaced fish meal of P. monodon diet, the hepatopancreas HSP70, and the contents of Na+-K+-ATPase and cortisol were significantly higher than those of the control group. In the acute salinity change, there was no significant difference in the survival rate of P. monodon at 48h under the two salinity stresses, and the four immune indexes showed different trends. The expression level of Cortisol was more prominent than that of HSP70, which could better reflect the stress degree of P. monodon. Most of the indicators showed a trend of rising and then falling and then rising compared with the original level, and the changes of the four indicators of hepatopancreas in the Diet B group were significantly higher than those in the Diet A group at most time point of the two salinities.