Total Edible Yield Research Articles

The Biochemical Composition and Quality of Adult Chinese Mitten Crab Eriocheir sinensis Reared in Carbonate-Alkalinity Water

Saline–alkaline aquaculture has become an important breakthrough in expanding the space available for aquaculture in China. However, the biochemical composition and quality of Eriocheir sinensis reared in carbonate alkalinity water are still unclear. Therefore, this study investigated the edible yield, coloration, and nutritional and flavor quality of Eriocheir sinensis. A significantly lower gonadosomatic index (GSI), meat yield (MY), and total edible yield (TEY) were detected in intensive pond (IP) samples than those in semi-intensive reed wetland (SIWR) (p < 0.05). Six color parameters in the hepatopancreas (p < 0.05) differed between IP and SIRW. The contents of crude protein and fat in the female hepatopancreas of IP were significantly higher than those in SIRW (p < 0.05). The concentrations of total monounsaturated fatty acids (∑MUFA), total essential fatty acids (∑EFA), and hypocholesterolaemic/hypercholesterolaemic ratio (h/H) in the female edible tissues checked were higher in IP than those in SIRW, with significant differences including ∑MUFA in the hepatopancreas and ovary, ∑EFA in the muscle, and h/H in the ovary (p < 0.05). Higher total free amino acid (∑FAA) contents of muscle were detected in SIRW than that in IP samples. Significantly higher K, Ca, Mg, Fe, and Zn contents in the ovary were detected in SIRW samples compared to IP (p < 0.05). Overall, Eriocheir sinensis reared in carbonate-alkalinity water is an important source of nutrients.

The effects of dietary L-theanine on the growth performance, non-specific immunity, antioxidant status, and intestinal microflora of female Chinese mitten crabs (Eriocheir sinensis)

L-theanine, a non-protein amino acid in tea, has been widely studied as an immune enhancer in poultry, livestock, and rodents. However, no studies have been performed on the application of L-theanine in aquaculture feed. To fill this research gap, we investigated the effects of L-theanine as a feed additive on the growth performance, immune function, antioxidant capacity, and intestinal flora of female Chinese mitten crab (Eriocheir sinensis) using biochemical assays, real-time polymerase chain reaction, and 16 S rRNA gene sequencing. In total, 300 one-year-old female Chinese mitten crabs were randomly divided into treatment groups supplemented with 0 (control), 0.5%, 1.0%, 1.5%, and 2.0% L-theanine (L0–L4, respectively; n = 4 replicates per group with 15 crabs per replicate). After eight weeks, the total edible yield was significantly higher in all treatment groups than in the L0 group (P < 0.05). Furthermore, the muscle yield (both P < 0.01) and hepatopancreas index (P < 0.01 and P < 0.05, respectively) were significantly higher in the L2 and L3 groups than in the L0 group. The gonadosomatic index was also significantly higher in the L2 group than in the L0 group (P < 0.01). Moreover, the hepatopancreas superoxide dismutase, acid phosphatase, total antioxidant capacity, and glutathione peroxidase activities increased, and the malondialdehyde content decreased in the L3 group compared to the L0 group (P < 0.05). Anti-lipopolysaccharide factor (ALF) 2 (i.e., ALF2), Toll-like receptor (i.e., TLR), and myeloid differentiation primary response gene 88 (i.e., Myd88) expression were also significantly up-regulated in the L2, L3, and L4 groups (P <0.01), and ALF1 and mammalian target of rapamycin (i.e., mTOR) expression were significantly up-regulated in the L3 group (P <0.01) compared to the L0 group. Overall, these results suggest that supplementation with 0.5–1.0% L-theanine positively affected the gut microbiota composition of female Chinese mitten crabs, improving their edible fraction, antioxidant capacity, immunity, and gut microbiota abundance.

Impact of Overwintering Hoard on the Edible Tissues, Muscle Quality, Hepatopancreas Color, and Proximate Biochemical and Amino Acid Compositions of Male Eriocheir sinensis

The Chinese mitten crab, Eriocheir sinensis, is a popular food and an important breeding crab in China. In order to pursue higher sales prices and improve breeding efficiency, many farmers often hoard these crabs, until around the Spring Festival or even later, before selling them. Therefore, considering the time span of hoarding, the present study was designed to check the quality (edible tissues, muscle quality, hepatopancreas color, proximate biochemical and amino acid compositions) of E. sinensis, before and after overwintering hoard. The hepatosomatic index before hoarding in winter was higher than that of after hoarding in winter, but the gonadosomatic index, meat yield, total edible yield, and condition factor were significantly ( p &lt; 0.05 ) lower after hoarding in winter. The texture profile analysis (TPA) of muscle, the springiness, chewiness, and cohesiveness after hoarding in winter were significantly ( p &lt; 0.05 ) higher than those before hoarding in winter. The redness and yellowness of the hepatopancreas before hoarding in winter were lower than those after hoarding in winter. No significant difference ( p &lt; 0.05 ) was found in moisture, crude protein, and crude lipid in hepatopancreas, gonad, and muscle tissues of male E. sinensis. The contents of all amino acids (except methionine and histidine) in hepatopancreas, gonad, and muscle before hoarding in winter were higher than after hoarding, but there was no significant difference ( p &lt; 0.05 ) in hepatopancreas and gonad. While, in the muscle, the contents such as threonine, serine, glutamic acid, glycine, alanine, leucine, phenylalanine, histidine, and arginine, before hoarding in winter, were significantly ( p &lt; 0.05 ) higher than after hoarding. This study showed that, for the male E. sinensis after overwintering hoard, the edible tissues and muscle quality increased, and, moreover, the hepatopancreas color and proximate biochemical and amino acid compositions of hepatopancreas and gonad have no significant changes, but the content of many good amino acids, ΣNEAA and ΣDAA, in muscle all decreased.

Comparison in biochemical composition and nutritional value of the invasive Chinese mitten crab, Eriocheir sinensis, from Lake IJsselmeer, The Netherlands, and its natural habitat, the Yangtze River, China

Abstract The Chinese mitten crab, Eriocheir sinensis, as an invasive species, has formed a large wild population and become a new fishery resource in Lake IJsselmeer (IL) of The Netherlands. This study was conducted to quantify edible tissue indices, proximate composition, fatty acid and amino acid contents of crabs collected from IL, and make a comparison with wild crabs from the species’ native habitat, the Yangtze River (YZ). It showed that: (1) YZ had a significantly higher meat yield and total edible yield; (2) YZ showed higher lipid and protein contents at a lower gonadosomatic index; (3) IL had a higher level of C20:4n6, C20:5n3 and C22:6n3 in the hepatopancreas, and higher EPA and DHA in the ovaries; (4) although YZ has a clear advantage, both IL and YZ muscle were high in contents of essential as well as delicious amino acids. In conclusion, adult E. sinensis living in IL, The Netherlands, also have a rich nutritional value with a high edible yield.

Trash fish facilitates protection against the deterioration in nutritional quality of adult female Chinese mitten crabs Eriocheir sinensis during winter

In this study, we conducted a cage-culture trial to evaluate the gonadal development and nutritional quality of adult female Chinese mitten crabs (Eriocheir sinensis) fed a formulated diet (FD), traditional diet (TD) or trash fish (TF) during wintering. The results revealed a marked reduction in the hepatopancreatic index (HSI) during 90 days of wintering, and that crabs fed the TF diet had a significantly higher HSI and total edible yield than those fed the TD diet after wintering (p < 0.05). In terms of proximate composition, protein and lipid contents in the ovaries showed significant increases over the wintering period, whereas there was a significant reduction in hepatosomatic protein levels. Among the three overwintering treatments, the contents of ovarian proteins and hepatosomatic lipids were significantly higher in TF crabs. Although the redness (a*) of the carapace and ovaries was found to have increased significantly during wintering, there was a significant reduction in hepatosomatic redness, which was consistent with the total carotenoid contents detected in these tissues. Moreover, among the three treatments, hepatosomatic redness was significantly higher in TF treatment after the overwintering period. In addition, nutritional quality index assessments revealed that crabs in the TF and TD groups were characterized by the highest and lowest values respectively. In conclusion, we found that the nutritional quality of adult female E. sinensis undergoes a marked decline during the wintering period. However, the provision of a TF diet can contribute to protecting against a deterioration in the nutritional quality of crabs maintained over winter.

Ovarian fullness affects biochemical composition and nutritional quality of female swimming crab Portunus trituberculatus

Ovary is an important edible component of female crabs in many countries, and ovarian fullness (maturity) had become an important quality indicator used for crab marketing. Adult females Portunus trituberculatus are typically divided into four grades (Grade I - Ⅳ) based on ovarian fullness in the carapace during the marketing. This study investigated the chemical composition and nutritional quality of market size female P. trituberculatus. The gonadosomatic index (GSI), hepatosomatic index (HSI) and total edible yield (TEY) showed a stepwise increase from Grade Ⅰ to Ⅳ (P < 0.05). Crude protein and total lipid content in both ovaries and muscle significantly increased with fullness, where Grade Ⅱ - Ⅳ had significantly higher lipid contents in the hepatopancreas compared to Grade Ⅰ. Redness (a*) of carapace and ovaries was consistent with the total carotenoid contents in tissues. Σ MUFA in both ovaries and muscle increased with crab grade, while Σ PUFA in ovaries and muscle, as well as Σ MUFA in the hepatopancreas decreased. For most amino acids in ovaries and muscle were also found to increase with grade. Higher-graded females generally had higher TEY, color parameters and better nutritional quality in edible tissues than the Grade I and II, which appears related to their different ovary stages of P. trituberculatus.

Composition and nutritional qualities of edible tissues of Chinese mitten crab (Eriocheir sinensis) from Ya Lake over different months

The edible tissue yield, proximate, fatty acid, and free amino acid composition were examined and compared among Chinese mitten crabs (Eriocheir sinensis) samples from Ya Lake over different months. Regardless of gender, the gonadosomatic index (GSI) was higher in May and June than that in August and September (P < 0.05), whereas the hepatopancreas index (HSI), meat yield (MY), and total edible yield (TEY) were higher in August and September. For proximate composition, regardless of gender, the total lipid content in the hepatopancreas was significantly higher in September than in other months, and the total lipid and protein content in the gonads was the highest. Furthermore, the content of EPA in female hepatopancreas was the highest in August. Regardless of sex, C16:1n7 in muscle was higher in September than in other months (P < 0.05), and the ratio of n-3/n-6 PUFA was the highest. Moreover, females had the highest glutamate and arginine content in their ovaries in August (P < 0.05). Among the muscles, both sexes contained higher levels of alanine and glutamate in September. Thus, the edible tissue yield, nutritional quality, and taste of Ya Lake E. sinensis in September were the best.

Comparison of nutritional quality and nutrient compositions of three edible tissues from different sourced cultured female mud crabs (Scylla paramamosain)

This study compared the nutritional quality and nutrient compositions of female mud crabs cultured in the coastal area around the Bohai Sea (BMC), the East China Sea (EMC), and the South China Sea (SMC). The results showed that BMC had the highest hepatopancreas index and meat yield and EMC had the highest gonadosomatic index and total edible yield. The protein content in the edible tissues of EMC and SMC was significantly higher than that of BMC. The essential amino acid index in the muscle and gonads of three-sourced female crabs was quantitatively higher than 70, meaning that the amino acid compositions in the muscle and gonads of BMC, EMC, and SMC showed good performance. The mineral element data revealed that they were all excellent mineral sources, especially the Zn content in the gonads, which was approximately 15 mg 100 g−1. Meanwhile, the polyunsaturated fatty acid contents of BMC were significantly higher than those of EMC and SMC, and BMC also had abundant eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), particularly in the muscle. Hence, although EMC and SMC contained more protein than BMC, the nutritional quality and nutrient composition of BMC was slightly better than those of EMC and SMC.

Comparison of the growth performance and nutritional qualities of Chinese mitten crab (Eriocheir sinensis) with different stocking densities in rice-crab culture systems

This study investigated the comparison of the growth performance and nutritional qualities of Chinese mitten crab (Eriocheir sinensis) with different stocking densities (D02: 0.2 inds/m2; D03: 0.3 inds/m2; D04: 0.4 inds/m2; D05: 0.5 inds/m2; D06: 0.6 inds/m2) in rice-crab culture systems. The result showed the D04 group crabs had higher gonadsomatic index (GSI), meat yield (MY), total edible yield (TEY), crude lipid levels of hepatopancreas and the crude protein levels of gonads than those of other groups crabs. The muscle and gonads of D04 group crabs had better essential amino acid (EAA) levels. The levels of polyunsaturated fatty acids (PUFA) in the hepatopancreas and gonads were significantly increased in the D04 group crabs compared with other groups crabs. The stocking density of D04 group has a more obvious promotion effect on the relative expression of molting and growth related genes compared with other groups. Taken together, it can generally be concluded that the male crabs raised by 0.4 inds/m2 have the highest nutritional quality even though they are not the largest crabs.

A comparative evaluation of the nutritional quality of three wild populations of female mitten crabs (Eriocheir sensu stricto) in northern China

Abstract There are three major wild populations of mitten crab (Eriocheir sensu stricto), Suifenhe River (SF), Tumenjiang River (TM) and Liaohe River (LH) in northern China. However, the information on the nutritional quality of these three populations of crabs is still scarce. Thus, we investigated and compared the tissue indices, total edible yield, proximate composition, fatty acid compositions and amino acid contents of these wild crab populations. We showed that: (1) TM population had the highest meat yield among the three populations; (2) TM recorded the highest moisture and the lowest total lipid content in ovary and muscle; (3) a higher level of total n-3 poly-unsaturated fatty acids was found in TM, except for the ovary in SF; (4) the three populations had similar essential amino acids scores. In conclusion, Eriocheir s.s. from these three populations all showed a high nutritional quality suitable for humans, especially the TM, which contains more eicosapentaenoic acid and docosahexaenoic acid.

Comparative study on the nutrition composition of adult male Chinese mitten crab (Eriocheir sinensis) with different coloured hepatopancreases

High lethality of white hepatopancreas syndrome has caused large economic loss of Chinese mitten crab (Eriocheir sinensis). Hepatopancreas colour of diseased crabs is gradually lighter, turning from golden yellow to yellow-white to white. This study investigated composition of conventional nutrients in three edible parts of different coloured hepatopancreases of adult males, including normal yellow hepatopancreas group (Control), yellow-white hepatopancreas group (YWH) and white hepatopancreas group (WH). No significant differences were observed in tissue indices and total edible yield among three crab types; however, condition factor level in crabs of YWH and WH was significantly lower. Dry matter content was significantly reduced in crabs of WH, especially crude fat level of hepatopancreas in WH males. Levels of all the amino acids of WH crabs in muscles and gonads were significantly lower than that of control. Proportion of saturated fatty acids and monounsaturated fatty acids were much lower in hepatopancreas of WH crabs than those of control, while proportion of polyunsaturated fatty acids and highly unsaturated fatty acids were significantly higher. Overall, YWH and WH do not affect growth. WH crabs showed poor nutritional quality, and nutritional value of YWH was in the middle as transition state between control and WH.

A comparative evaluation of the nutritional quality of Eriocheir sinensis and Eriocheir japonica (Brachyura, Varunidae)

Abstract The Japanese mitten crab Eriocheir japonica is an economically important species widely distributed throughout the East Asia region, but information on the compositional characteristics and nutritional quality of E. japonica is still scarce. Thus, this study was conducted to compare the edible tissue indices, proximate composition, fatty acid profiles and amino acid contents between wild E. sinensis and E. japonica. It showed that: (1) both E. sinensis and E. japonica have a high total edible yield (approximately 40%); (2) E. sinensis and E. japonica have a similar proximate composition, except for total lipids; (3) female E. japonica have higher percentages of C18:3n3, C20:5n3 and C22:6n3; (4) E. sinensis have higher levels of essential amino acids than E. japonica in muscle. In conclusion, these results demonstrated that wild E. japonica is rich in omega-3 fatty acids, and both E. sinensis and E. japonica are aquatic food of high nutritional value, with a high edible yield.

Growth performance, gonad development and nutritional composition of Chinese mitten crab Eriocheir sinensis selected for growth and different maturity time

Chinese mitten crab is an important aquaculture species in China, and a selective breeding program has been operated for the economic traits of growth and different maturity time of this species since 2010. This study aimed to evaluate the growth performance and nutritional composition of two selected lines, i.e. early-maturing strain (EM) and late-maturing strain (LM), and control population without genetic selection cultured in identical outdoor earth ponds. The results showed that: (1) The average body weight of two selective lines were always higher than the control during the pond culture of adult E. sinensis. Among two selected lines, the average body weight of the EM was relatively higher than that of LM between May and July, but EM had the relatively lower body weight than the LM during the late culture stage between Sept and Nov. (2) Compared to control population, despite of males or females, pubertal molting of EM and LM were occurred earlier and later respectively than that of control both, and there were around 15–20 days earlier for the pubertal molting of EM. For gonadosomatic index (GSI), EM had the higher GSI than LM and control populations between Oct.10 and Nov. 20 for males as well as between Sep.20 and Oct. 30 for females during the gonadal development cycle; (3) For the edible indices of adult crabs at the harvest, EM had the significantly higher of GSI and total edible yield (TEY) than LM, and control had the lowest hepatosomatic index among three populations (P < .05); (4) For proximate composition, three populations generally had the close proximate contents in three edible tissues (muscle, gonads and hepatopancreas), but female LM had the significantly lower lipid contents in both hepatopancreas and gonad than EM and control (P < .05); (5) As for fatty acid, female LM had the higher percentages of C18:3n3, total polyunsaturated fatty acids (ΣPUFA) and total long chain polyunsaturated fatty acids (Σ LC-PUFA) in muscle and hepatopancreas than the other populations, while EM had the significantly higher percentages of C22:6n3 in gonads than LM for both males and females; (6) Selective breeding had no apparent effects on amino acid compositions and contents of muscle and all essential amino acid scores were above 100. In summary, selective breeding provides a useful means for the improvement of growth and time of pubertal molting for E. sinensis, but has limited effects on their nutritional composition.

Impacts of different feeding modes on the gonadal development, total edible yield, and nutritional composition of male Chinese mitten crab (Eriocheir sinensis)

This study analyzed the tissue indices, proximate composition, fatty acid and amino acid composition of edible tissues of male E. sinensis under three feeding modes (formulated diets (FD), natural diets (ND), and traditional diets (TD)). The results showed that different feeding modes had no impacts on the overall gonadal development, as no significant difference was found in gonadsomatic index among three treatments. For edible yield, three modes all had similar levels of the meat yield, hepatosomatic index, and total edible yield. Although different feeding modes did not affect the individual edible yield and gonadal development, significant differences were detected in the nutritional composition of males from three modes. For proximate composition, significant differences were found in the total lipids of gonads and the carbohydrate of hepatopancreas and meat. For fatty acids, crabs from ND had a higher proportion of monounsaturated fatty acids. In gonads and hepatopancreas, FD had a higher proportion of long-chain polyunsaturated fatty acids. For amino acids, FD had higher amino acid contents, while ND had the lowest. Except tryptophan, the essential amino acids scores of the meat were all greater than 100. As there was no significant difference on meat quality and meat yields between three feeding modes, this study suggests that the formulated diet could replace the natural diet and traditional diet towards sustainable crab farming in future.

Fattening culture improves the gonadal development and nutritional quality of male Chinese mitten crab Eriocheir sinensis

The Chinese mitten crab, Eriocheir sinensis, is an important aquaculture species in China, and >80% of aquaculture production comes from outdoor earth-ponds. Fattening immature E. sinensis with a high-quality diet has been proven to effectively improve male gonadal development and nutritional value. This study aimed to investigate the effects of different fattening periods on male gonadal development and nutritional quality of pond-reared male E. sinensis post pubertal molting. The gonadosomatic index (GSI) increased significantly during the 60-day fattening period, while significant increases in meat yield and total edible yield were only found between Day 0 and Day 20. The gonadal system, consisting of testis, deferens and accessory gland, had the highest increase during the fattening period. The fattening period did not significantly affect the proximate composition of hepatopancreas; however, the protein contents of male gonad and muscle increased significantly. The moisture and carbohydrate contents of the gonad, as well as muscular moisture, decreased significantly during the 60-day fattening period. A significant decrease in gonadal lipid contents was found between Day 40 and Day 60, while the trend of “low-high-low” was found in muscular carbohydrate levels during the whole fattening period. Significant increases were found in the percentage of triglyceride (TG) and free fatty acids (FFA) in male gonad, while decreases were found in the percentages of cholesterol and phospholipid in male gonads, FFA in hepatopancreas and TG in meat during the 60-day-fattening period. With respect to fatty acid composition, a trend of “high-low-high” was found for the percentages of mono-unsaturated fatty acids (MUFA), poly-unsaturated fatty acids (PUFA) and long chain poly-unsaturated fatty acids (LC-PUFA) in male gonad and hepatopancreas. The percentages of saturated fatty acid (SFA) and MUFA in muscle decreased significantly, while the significant increases were found in muscular PUFA and LC-PUFA during the fattening period. Total amino acid (TAA) levels of male gonads increased dramatically during the fattening period, and essential amino acid scores of male gonad and muscle were >100 for all essential amino acids (EAA) after the 60-day fattening period. In conclusion, these results suggest that an appropriate fattening period is approximately 40 days for pond-reared male E. sinensis post pubertal molting.

Effects of fattening period on ovarian development and nutritional quality of adult female Chinese mitten crab Eriocheir sinensis

The fattening of immature female Chinese mitten crab (Eriocheir sinensis) with high quality diets is an effective mechanism for improving ovarian development and nutritional quality. This study investigated the ovarian development and nutritional quality of female E. sinensis during an 80-day fattening period. The results showed that the gonadosomatic index (GSI) and total edible yield of female E. sinensis increased in a stepwise manner over the course of the fattening period, in synchrony with a decrease in feed consumption and feed cost. Crude protein, total lipid and total carbohydrate in ovaries increased significantly over the course of the fattening period, with the highest crude protein content in both the hepatopancreas and meat observed at Day 40. There was a stepwise increased in the content of triacylglycerol (TAG) and cholesterol (CHO) and phospholipid (PL) in ovary and meat, respectively. On the contrary, the content of free fatty acid (FFA) and PL in ovaries and hepatopancreas as well as the meat TAG and FFA decreased significantly over the course of the fattening period. In ovaries, the highest concentration of polyunsaturated fatty acid (∑PUFA) was observed at Day 60, whilst the highest total monounsaturated fatty acid (∑MUFA) in meat was detected at Day 40. The highest content of ∑MUFA in hepatopancreas, and the ∑PUFA and total long chain polyunsaturated fatty acid (∑LC-PUFA) in meat were detected at Day 80, while the highest hepatopancreas ∑PUFA was detected at Day 0. The content of total essential amino acids (∑EAA) and total amino acids (TAA) in ovaries and meat increased significantly during the fattening period of Day 0 to Day 40, while no significant increase was detected on the TAA during the period of Day 40 to Day 80. Essential amino acid scores (EAAS) of ovary and meat were >100 for all essential amino acids (EAA), and fattening culture did not significantly improve EAAS for ovary and meat. In conclusion, the fattening could improve the total edible yield and nutritional values of female E. sinensis. Considering the fattening performance and feed cost, the appropriate fattening period should be 40–60 days for pond-reared female E. sinensis post puberty molting.

Comparison between the nutritional qualities of wild-caught and rice-field male Chinese mitten crabs (Eriocheir sinensis)

This study investigated the tissue indices and composition of conventional nutrients in three edible parts (hepatopancreas, gonads, and muscle) of wild-caught and rice-field male Eriocheir sinensis. The hepatopancreas index (HSI) of rice-field crabs was significantly higher than that of wild-caught crabs, whereas the gonadosomatic index (GSI) was significantly lower. No significant differences were observed in the muscle yield (MY), total edible yield (TEY), condition factor (CF), or proximate composition between the two crab types, except for the crude protein content in the hepatopancreas of rice-field crabs, which was significantly higher. The amino acid assessment results showed that both types of crabs were high-quality protein sources, and the main amino acids contained in both crabs are glutamic acid, aspartic acid, and alanine, but wild-caught crabs had higher content of umami amino acids. The mineral content in wild-caught crabs was higher than that in rice-field crabs. Monounsaturated and polyunsaturated fatty acids (MUFA and PUFA) were much higher in the edible tissues of wild-caught crabs than in the tissues of rice-field crabs. Overall, both crab types showed good nutritional quality suitable for human dietary needs. However, wild-caught crabs showed superior quality to rice-field crabs in terms of minerals, fatty acid composition, and taste.

The Effect of Diet on Ovarian Development and Nutritional Tissue Composition of Portunus trituberculatus

This study investigated the effects of feeding trash fish (TF), formulated diet (FD), and mixed diets (MD) on ovarian development, fattening performance, and nutritional quality of P. trituberculatus. Formulated diet treatment resulted in lower gonadosomatic index, hepatosomatic index, meat yield, and total edible yield than the other treatments. It also showed lower protein (7.88%), lipid, and ash content in hepatopancreas and muscle, compared to the other treatments. Different diets significantly affected the contents of C16:0, C18:1n9, C18:2n6, C18:3n3 and C20:5n3 of hepatopancreas. FD treatment resulted in lower essential amino acids and non-essential amino acid contents in the muscle compared to TF and MD treatments. The highest and the lowest essential amino acids scores were found in the TF and FD treatments, respectively. In conclusion, these results indicated that FD is not suitable and requires further development for sub-adult crabs, while MD would be the recommended for fattening female P. trituberculatus.

Ovarian development and nutritional quality changes of the wild-caughtPortunus trituberculatusduring the artificial fattening period

A female swimming crab (Portunus trituberculatus) with fully developed ovaries is considered one of the most nutritious types of seafood. The fishing yield of P. trituberculatus in China has always been high; however, its economic value has been low and unreliable due to poor ovarian development and low nutritional value. Artificial fattening is an effective way to improve the value of wild-caught crabs, and this study focused on analysing the ovarian development and nutritional quality of the female P. trituberculatus during an artificial fattening period. Therefore, this study provides scientific evidence on the effects of artificial fattening on female P. trituberculatus and can guide the development of nutritional quality regulations for wild-caught female crabs during the fattening process. The results showed that the ovaries of the wild female P. trituberculatus developed gradually. The ovarian morphology became bulkier, while the gonadosomatic index (GSI) and total edible yield (TEY) were significantly improved after artificial fattening. Significant changes in the nutritional components of the edible tissues were observed, and the moisture content in the ovaries and hepatopancreas decreased continually, while both the protein and fat content in the ovaries significantly increased. Moreover, the fat content in the hepatopancreas significantly increased. The saturated fatty acids(ΣSFA) in the ovaries and hepatopancreas had an increasing trend after fattening, while ΣPUFA and Σn-3PUFA first decreased and then increased. In contrast, the ratio of Σn-3PUFA to Σn-6PUFA decreased steadily. However, the fatty acid composition of the muscles did not change significantly. The levels of all the amino acids increased continuously during the fattening process, and EAA increased significantly in the early stages of the fattening period. Consequently, all amino acids became nonlimiting amino acids after fattening. Furthermore, the ratio of EAA/NEAA in the ovaries increased continually until the end of the fattening period. On the other hand, the fatness and TEY increased significantly after artificial fattening. In addition, the nutritional value significantly improved with the exception of the high-quality fatty acids in the ovaries and hepatopancreas, which were slightly lower in both.

Biochemical Composition of Pond-Cultured vs. Wild Gravid Female Mud CrabScylla paramamosainin Hainan, China: Evaluating the Nutritional Value of Cultured Mud Crab

Mud crab (MC) aquaculture is rapidly developing fast worldwide, and there is a high consumer demand for Scylla paramamosain. Demand for MCs is especially high in China, where such crabs, especially the gravid females, are regarded a delicacy. In Hainan Island, pond-rearing wild MC juveniles in the presence of local trash fish and shrimps in brackish water has been shown to be successful. The nutritional value of cultured MC, however, has not been evaluated. In this paper, the biochemical composition of pond-cultured and wild gravid female MCs was studied. The cultured MCs had a higher ratio of total edible yield than the wild ones. The contents of crude protein and crude lipid in the cultured MCs were significantly lower than in the wild MCs (P < 0.05). Furthermore, the total amino acid (TAA) and essential amino acid (EAA) contents of gonads in the wild MCs were both significantly higher than those in the cultured MCs (P < 0.05). The TAAs and EAAs of claw and body muscles in cultured MCs, however, were significantly higher (P < 0.05). There were no significant differences in the contents of polyunsaturated fatty acids (PUFAs), n-3 fatty acids, and n-6 fatty acids in the gonad of bothMCgroups, whereas the contents of total saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) were significantly different between the wild and the cultured MCs (P < 0.05). Furthermore, there were no significant differences in the contents of SFAs, MUFAs, and PUFAs in both claw and body muscle between the wild and cultured MCs.