To investigate the effects of three alternative protein sources—Hermetia illucens larvae meal (HIM), Chlorella meal (CM) and stickwater meal (SWM)—on the vitellogenin in female largemouth bass (Micropterus salmoides), these protein sources were used to replace 0% (control group, FM; containing 40% fishmeal), 25% and 50% of the fishmeal in the diet. A total of seven isonitrogenous and isolipidic diets were formulated (FM, 25% HIM, 50% HIM, 25% CM, 50% CM, 25% SWM and 50% SWM). The healthy female fish with an initial body weight of 353.57 ± 28.12 g were fed the experimental diets for eight weeks. The results showed that the viscerosomatic index, gonadosomatic index and oocyte diameter of broodstock in the 50% HIM group were significantly higher than those in the FM group. The 50% HIM group showed the highest rate of stage IV oocytes and the lowest share of stage II oocytes. Hepatic vitellogenin (Vg) mRNA expression was significantly upregulated in the 50% HIM group, whereas ovarian mRNA expression of Vg and vitellogenin receptor (VgR) was significantly upregulated in the 25% SWM and 50% SWM groups. In conclusion, replacing 50% of dietary fishmeal with Hermetia illucens larvae meal can promote ovarian development in largemouth bass broodstock by increasing the gonadosomatic index and the expression of genes involved in vitellogenin synthesis.

This study investigated the effects of choline on endogenous phospholipid synthesis in Chinese mitten crab (Eriocheir sinensis). Chinese mitten crabs (0.40 ± 0.03 g) were fed diets supplemented with 0%, 0.2% or 0.4% choline under low phospholipids (low-PL) or normal phospholipids (normal-PL) for eight weeks. The results showed that feeding the Chinese mitten crab with 0.4% choline in low-PL diets up-regulated significantly the relative mRNA expressions of neuropathy target enzyme 1 (nte1), phospholipase A2 (pla2) and phospholipase B (plb). Moreover, the crabs fed the 0.4% diet at low-PL diets enhanced hepatopancreatic fatty acid binding protein 3 (fabp3), fatty acid transporter protein 4 (fatp4), carnitine palmitoyltransferase-2 (cpt-2), carnitine acetyltransferase (caat), carnitine palmitoyltransferase-1a (cpt-1a) and carnitine palmitoyltransferase-1b (cpt-1b). However, feeding the mitten crabs 0.2% choline in the normal-PL diets diets up-regulated significantly the relative mRNA expressions of nte1, pla2 and plb. These results indicate that 0.4% choline up-regulates the expressions of genes involving in phospholipids synthesis of Chinese mitten crab fed with low-PL diets, while 0.2% choline improved the genes involved in phospholipid decomposition under normal-PL conditions.

Methionine (Met) is an essential amino acid for aquatic animals. However, its role and underlying mechanisms in ovarian development in the giant river prawn (Macrobrachium rosenbergii) are currently unknown. This study investigated the role of dietary Met on vitellogenesis and ovarian maturation in M. rosenbergii broodstock and elucidated its underlying mechanisms. Therefore, 720 adult female M. rosenbergii (9.66 ± 0.07 g) were fed diets containing 0.57%, 0.80%, 0.95%, 1.07%, 1.32% and 1.47% Met in quadruplicate for eight weeks. The results showed that feeding the M. rosenbergii fed on dietary Met at 0.95% and 1.07% increased significantly specific growth rate than those fed on the other diets (P < 0.05). Moreover, feeding the M. rosenbergii on Met at 0.95% significantly increased the crude lipid content in the whole body compared to other diets. Furthermore, the M. rosenbergii fed on dietary Met at 0.95% and 1.07% significantly increased the gonadosomatic index than 0.57%. However, feeding the prawns on Met 0.95% significantly decreased the vitellogenesis-inhibiting hormone (VIH) content in the hemolymph and eyestalks than 0.57%. The prawns fed on Met at 0.80% significantly up-regulated the mRNA expression of protein kinase A (pka) and vitellogenin (vg) genes than other diets. Moreover, the prawns fed on Met at 1.07% significantly increased Vg and cyclic adenosine monophosphate (cAMP) contents in the hemolymph and significantly up-regulated the mRNA expression of the vitellogenin receptor (vgr) in the ovary. Met promoted whole-body lipid deposition while significantly reducing hepatopancreatic highly unsaturated fatty acids and polyunsaturated fatty acids in M. rosenbergii broodstock. Taken together, an appropriate level of dietary Met (0.80% to 0.95%) promotes hepatopancreatic Vg synthesis, transport, and accumulation in the ovary by inhibiting VIH synthesis, thereby activating the cAMP/PKA pathway and promoting ovarian development and maturation.

The global aquaculture industry faces increasing challenges, including the need to improve feed efficiency, reduce reliance on fishmeal, and mitigate disease risks while ensuring sustainable production [...]

In order to investigate the effects of choline on the synthesis of endogenous phospholipids in Eriocheir sinensis, this experiment was conducted by adding 0%, 0.2% and 0.4% choline to low phospholipid (0% PL) and normal phospholipid (2% PL) diets, respectively, and feeding the crabs with an initial body weight of 0.4 g for 8 weeks. The results showed that diets supplementation with 0.4% choline significantly upregulated the relative mRNA expression of neuropathy target enzyme 1 (nte1), phospholipase A2 (pla2) and phospholipase B (plb) in the low phospholipids condition. In addition, dietary 0.4% choline significantly increased the relative mRNA expression of hepatopancreatic fatty acid binding protein 3 (fabp3), fatty acid transporter protein 4 (fatp4), carnitine palmitoyltransferase-2 (cpt-2), carnitine acetyltransferase (caat), carnitine palmitoyltransferase-1a (cpt-1a) and carnitine palmitoyltransferase-1b (cpt-1b) in juvenile Chinese mitten crab. Dietary 0.2% choline significantly up-regulating the relative expression of fatty acid synthase (fas), and fatty acid elongase 6 (elovl6) mRNA relative expressions in the 2% PL diets. This study shows that dietary supplementation with 0.4% choline could improve phospholipids synthesis of Chinese mitten crab under low phospholipids condition, and 0.2% Choline could improve the decomposition and remodeling of phospholipids in the normal phospholipids condition.

The current study was designed to explore the effects of dietary vitamin E on the ovarian development and health of female largemouth bass (Micropterus salmoides). Five experimental diets were formulated, each containing varying concentrations of vitamin E: 78.25, 98.36, 209.31, 437.77, and 915.49 mg/kg of vitamin E. These diets were administered to female largemouth bass (445.52 +/- 13.57 g) for 35 days. The results demonstrated that fishes fed with 209.31 mg/kg vitamin E exhibited a significantly higher gonadosomatic index (GSI), visceral steatosis index, absolute fecundity, and relative fecundity compared to those fed with 78.25 mg/kg of vitamin E (P < 0.05). Meanwhile, it was observed that a predominant number of ovarian cells in fish fed 209.31 and 437.77 mg/kg of vitamin E had advanced to maturation, primarily consisting of mature oocytes at stage IV and V. Dietary vitamin E supplementation significantly upregulated the expression of genes involving vitamin E transfer, ovarian development, and hormone, including alpha-tocopherol transfer protein, luteinizing hormone, follicle-stimulating hormone, vitellogenin receptor (vgr), vitellogenin (vg), 17-beta-hydroxysteroid dehydrogenase (17 beta-hsd), cyclin-dependent kinase 2 (cdk2), and cytochrome P450 family 17 (cyp-17), with the highest expression levels detected in the 209.31 mg/kg group (P < 0.05). Additionally, 209.31 mg/kg of vitamin E also significantly increasing the immunity by reducing the activities of glutamic oxaloacetic transaminase and glutamic pyruvic transaminase in the serum, while increased the activities of alkaline phosphatase and acid phosphatase when compared to the 78.25 and 915.49 mg/kg groups (P < 0.05). 209.31 and 437.77 mg/kg of vitamin E significantly enhanced the antioxidant capacity of fish (P < 0.05). The optimal dietary vitamin E requirement was determined as 255.10-292.72 mg/kg based on GSI, absolute fecundity, and the expression levels of vg and vgr. In conclusion, the addition of 255.10 292.72 mg/kg of vitamin E to the diet of largemouth bass broodstock is recommend to enhance ovarian development.

Housefly maggot larvae (HML) have been identified as a potential alternative animal diet for the fattening process of the Chinese mitten crab (Eriocheir sinensis). However, the feasibility and potential impacts of HML supplementation require further investigation. The present study evaluated the effects of dietary HML on the growth indices, nutrient compositions, antioxidant activity, and texture profiles of edible tissues of E. sinensis. The results showed that dietary HML supplementation effectively improved the hepatic steatosis index of both genders and sweet amino acid content of edible tissues (except for male gonad) (p < 0.05). Additionally, dietary HML significantly increased the total antioxidant capacity in the gonad and female muscle (p < 0.05). For the textural properties, HML feeding significantly improved the adhesiveness in the male muscle, and the cohesiveness, chewiness, and resilience in the female muscle (p < 0.05). Furthermore, HML feeding significantly decreased the levels of the equivalent umami concentration of the male gonad, male muscle, and hepatopancreas (p < 0.05). Conversely, HML feeding significantly increased the sweetness value in the muscle, hepatopancreas, and female gonad (p < 0.05). Our findings indicate that HML could serve as a viable alternative feed for fattening to improve the edible yield and change the flavor characteristics in E. sinensis.

With the rapid development of aquaculture, the shortage of high-quality dietary ingredients has become a critical problem limiting the sustainable development of aquaculture [...]

The insufficient of fish meal has been become a prominent problem with the development of the aquaculture industry. Therefore, it is great significance that replacement fish meal using other protein sources for the sustainable development of aquaculture industry. In this study, fermented cottonseed meal (FCM) and fermented rapeseed meal (FRM) were used to replace fish meal in Chinese mitten crab. The ratio of FCM and FRM were set according to 1:2, 1:1, and 2:1, and were supplemented into 25% fish meal (FM-25) and 15% fish meal (FM-15) diets, respectively, to formulated 6 kinds of experimental diets. The feeding duration was 8 weeks. The results showed that the weight gain (WG) and specific growth rate (SGR) of crabs fed the diets containing 25% fish meal were significantly higher than crabs fed 15% fish meal diets. At 25% fish meal level, the WG and SGR of crabs fed the diet with 1FCM:1FRM were significantly higher than those fed the 1FCM:2FRM and 2FCM:1FRM diets. At 25% fish meal level, the crude lipid (CL) content of crabs fed the diet with 1FCM:2FRM were significantly higher than those fed the 2FCM:1FRM and 1FCM:1FRM. At 25% fish meal level, the activities of glutathione peroxidase (GPX) and peroxidase (POD) of crabs fed the diet with 1FCM:2FRM were significantly higher than those fed the 2FCM:1FRM and 1FCM:1FRM. At 25% fish meal level, the relative expression of peroxiredoxin (PRX) of crabs fed the diet with 1FCM:1FRM were significantly higher than those fed the 2FCM:1FRM and 1FCM:2FRM. In summary, diets supplemented with a mixture of fermented cotton meal and fermented rapeseed meal (1:1) can significantly improve the growth and antioxidant capacity of Chinese mitten crab.

In order to explore the effects of glutamate on the growth performance, antioxidant capacity and protein metabolism of juvenile Chinese mitten crab, 0%, 1% and 2% glutamate were supplemented to low protein (30%) and normal protein (35%) diets, respectively. There were 5 parallel tanks in each treatment, and the feeding duration was 8 weeks. The results showed that dietary glutamate did not significantly affect the weight gain of Chinese mitten crab. Diets supplemented with 2% glutamate significantly decreased the crude protein of crabs. The T-AOC of crabs fed the 30% protein diets was significantly lower than crabs fed the 35% protein diets. At 30% protein level, the superoxide dismutase (SOD) activity significantly increased with the increase in glutamate content. Dietary glutamate significantly down-regulated the relative expressions of mTOR, PI3K, S6K1 and 4EBP at 35% protein level. In conclusion, dietary glutamate cannot significantly increase the growth of Chinese mitten crab, but it can improve the antioxidant capacity in Chinese mitten crab under low protein conditions.

Lipids are key nutrients that affect the development of the ovary in aquatic animals. This study aimed to investigate the effects of different lipid sources on the ovarian development and health of Macrobrachium rosenbergii broodstock. The M. rosenbergii broodstock, with an initial body weight of 8.07 +/- 0.74 g, were fed diets containing 5 % fish oil (FO), soya bean oil (SO), rapeseed oil (RO), coconut oil (CO), and a 1:1 mixture of fish oil and soybean oil (MO) as lipid sources for a period of 56 days. The results indicated that there were no significant differences in survival rate (SR) and hepatopancreatic index (HSI) among the different groups (P > 0.05). However, the specific growth rate (SGR) and gonadosomatic index (GSI) in the MO group were significantly higher than other groups (P < 0.05). Additionally, fatty acid levels in diets directly influenced the fatty acid composition of prawn hepatopancreas, showing a similar trend to that observed in the diet itself. Furthermore, compared to the other trial groups, haemolymph levels of 17-beta estradiol (E2) and progesterone (PROG) were significantly increased in the MO group (P < 0.05). The ovarian section also exhibited better histomorphology and larger oocyte diameter in this group. Moreover, total antioxidant capacity was significantly increased in the MO group (P < 0.05). Saturated fatty acids in RO and CO groups could promote the expression of lipid synthesisrelated genes fatty acid synthase (fas) and acetyl-CoA carboxylase (acc), concurrently suppressing the expression of lipid catabolism-related genes acyl-CoA oxidase-1 (acox-1) and AMP-activated protein kinase alpha (ampk alpha) (P < 0.05). Conversely, polyunsaturated fatty acids in the MO group significantly up-regulated the expression levels of fatty acid binding protein-3 (fabp-3) and peroxisome proliferator-activated receptor gamma (ppar gamma) (P < 0.05). Based on the findings of hepatopancreatic tissue structure, it was determined that the use of a single vegetable oil resulted in some damage to the hepatopancreatic tissue structure of M. rosenbergii broodstock, leading to increased oxidative stress. In conclusion, it is recommended that a 1:1 mixture of fish oil and soybean oil be used as a dietary lipid source to effectively meet the nutritional requirements during the ovarian development period of M. rosenbergii broodstock. This combination also enhances antioxidant properties, promotes the synthesis of haemolymph steroid hormones and lipid metabolism in female prawns, thereby facilitating ovarian development and overall health of M. rosenbergii broodstock.

In order to study the effects of soybean isoflavones on the growth performance and lipid metabolism of juvenile Chinese mitten crabs, six experimental diets were formulated by gradient supplementation with 0%, 0.004% and 0.008% soybean isoflavones at different dietary lipid levels (10% and 15%). The groups were named as follows: NF-0 group (10% fat and 0% SIFs), NF-0.004 group (10% fat and 0.004% SIFs), NF-0.008 group (10% fat and 0.008% SIFs), HF-0 group (15% fat and 0% SIFs), HF-0.004 group (15% fat and 0.004% SIFs) and HF-0.008 group (15% fat and 0.008% SIFs). All crabs with an initial weight of 0.4 ± 0.03 g were fed for 8 weeks. The results showed that dietary supplementation with 0.004% or 0.008% SIFs significantly increased the weight gain and specific growth rate of crabs. Diets supplemented with 0.004% or 0.008% SIFs significantly reduced the content of non-esterified free fatty acids and triglycerides in the hepatopancreas of crabs at the 10% dietary lipid level. Dietary SIFs significantly decreased the relative mRNA expressions of elongase of very-long-chain fatty acids 6 (elovl6), triglyceride lipase (tgl), sterol regulatory element-binding protein 1 (srebp-1), carnitine palmitoyltransferase-1a (cpt-1a), fatty acid transporter protein 4 (fatp4), carnitine palmitoyltransferase-2 (cpt-2), Δ9 fatty acyl desaturase (Δ9 fad), carnitine palmitoyltransferase-1b (cpt-1b), fatty acid-binding protein 10 (fabp10) and microsomal triglyceride transfer protein (mttp) in the hepatopancreas of crabs. At the 15% dietary lipid level, 0.008% SIFs significantly increased the relative mRNA expressions of fatty acid-binding protein 3 (fabp3), carnitine acetyltransferase (caat), fatp4, fabp10, tgl, cpt-1a, cpt-1b and cpt-2 and significantly down-regulated the relative mRNA expressions of Δ9 fad and srebp-1. In conclusion, SIFs can improve the growth and utilization of a high-fat diet by inhibiting genes related to lipid synthesis and promoting lipid decomposition in juvenile Chinese mitten crabs.

This study aimed to investigate the effects of arginine (Arg) on the vitellogenesis and ovarian maturation of Chinese mitten crab. Six isonitrogenous and isolipidic diets (1.83, 2.52, 3.26, 3.96, 4.81 and 5.52 % Arg) were fed to adult female Chinese mitten crab (60.05 ± 4.33 g). The feeding period lasted for eleven weeks. The results showed that gonadosomatic index of crabs increased with increasing dietary Arg concentrations from 1.83 % to 2.52 % and significantly decreased from 2.52 % to 5.52 %. The quadratic regression analysis based on gonadosomatic index estimated that the optimal Arg requirement for adult female crabs was 2.60 %. Dietary supplementation with 2.52 % Arg significantly increased the crude protein concentration in the ovary. A dose of 2.52 % Arg significantly decreased the vitellogenesis-inhibiting hormone (VIH) content in the hemolymph. Arg (2.52 %) significantly upregulated the Vg and protein kinase A (PKA) gene expressions and increased the cyclic adenosine monophosphate (cAMP) concentration in the hepatopancreas. Moreover, dietary supplementation with 2.52 % Arg significantly decreased the cyclic guanosine monophosphate (cGMP) concentration and downregulated protein kinase G (PKG) and p38 mitogen-activated protein kinase (p38 MAPK) gene expression. Arg at 2.52 % significantly increased hemolymph Vg content and the gene expression of the vitellogenin receptor (VgR). In conclusion, Arg at 2.52 % improved vitellogenesis and ovarian maturation by reducing the VIH content and regulating Vg expression via the cGMP/cAMP pathway.

EDITORIAL article Front. Immunol., 12 September 2023Sec. Comparative Immunology Volume 14 - 2023 | https://doi.org/10.3389/fimmu.2023.1274213

本试验旨在研究脱脂黑水虻幼虫粉替代饲料中不同比例鱼粉对中华鳖稚鳖生长性能、肝脏抗氧化指标、肝脏和肠道消化酶活性、肠道组织形态和菌群的影响.配制5种等氮等脂的试验饲料,5种试验饲料中脱脂黑水虻幼虫粉替代鱼粉的比例分别为0(F0,作为对照)、15％(F15)、30％(F30)、45％(F45)、60％(F60).选取初始体重为(4.98±0.18)g 的中华鳖稚鳖 175只,随机分为5组,每组5个重复,每个重复7只,进行为期8周的养殖试验.结果显示:脱脂黑水虻幼虫粉替代饲料中不同比例的鱼粉对中华鳖稚鳖的摄食量、体比系数和肝体指数没有显著影响(P＞0.05).与对照组相比,F15、F30和F45组的终末体重、成活率、增重率和特定生长率均没有显著变化(P＞0.05),F60组则显著降低(P＜0.05);F15和F45组的饲料系数没有显著变化(P＞0.05),F30和F60组则显著升高(P＜0.05);F45和F60组的脂体指数显著降低(P＜0.05).各组间血清总蛋白、白蛋白、球蛋白和乳酸含量以及谷丙转氨酶、谷草转氨酶和碱性磷酸酶活性均无显著差异(P＞0.05);F45组血清酸性磷酸酶活性显著高于对照组(P＜0.05).F30组肝脏抗氧化酶和消化酶活性最高,F45组肠道淀粉酶和脂肪酶活性最高.高通量测序分析显示,F30组肠道中邻单胞菌属的相对丰度最低,鲸杆菌属的相对丰度较高,但是与对照组没有显著差异(P＞0.05);各组在门和属水平上的优势菌群相同,肠道菌群alpha多样性指数无显著差异(P＞0.05).综上所述,脱脂黑水虻幼虫粉替代饲料中30％～45％的鱼粉对中华鳖稚鳖的生长性能没有产生负面影响,并能改善肝脏抗氧化能力与肠道菌群结构.

The ovarian development of female crab can directly affect the nutritional value, broodstock fertility and health status of offspring and are essential for the success of the crab industry. This study evaluates the influences of dietary myo-inositol (MI) on the ovarian development of female Chinese mitten crab (Eriocheir sinensis). Three diets containing different MI levels (0, 1600 and 3200 mg/kg) were fed to 144 crabs (initial weight: 72.38 +/- 2.53 g) for 13 weeks. Crabs fed the diets with 1600, and 3200 mg/kg MI supplementation had significantly higher gonadosomatic index and yolk granule deposition in the ovary than those fed diets without MI supple-mentation. Crabs fed 1600 and 3200 mg/kg MI supplementation significantly enhanced vitellogenin synthesis in the hepatopancreas, vitellogenin contents in the hemolymph and vitellogenin receptor mRNA level in the ovary compared with those fed diets without MI supplementation. Simultaneously, cyclic adenosine monophosphate content and gene expression of retinoid X receptor, protein kinase A and ecdysteroid receptor in the hepato-pancreas, and ecdysteroid content in hemolymph significantly increased when 1600 and 3200 mg/kg MI were supplemented in diets. Moreover, crabs fed 1600 and 3200 mg/kg MI supplementation had significantly higher lipid content in the ovary than those fed the diets without MI supplementation. The neutral lipid content in the hepatopancreas tended to decrease as the dietary MI level increased, while the polar lipid content in the hepatopancreas and the neutral and polar lipid contents in the ovary tended to increase. Dietary MI supple-mentation significantly enhanced the expression of genes related to lipid catabolism, lipid absorption and transport in the hepatopancreas, and gene expression related to lipid absorption in the ovary, suggesting that MI could promote the transport of lipids to the ovary from the hepatopancreas for ovarian development. This study indicates that dietary 1600 mg/kg MI supplementation is sufficient to promote the ovarian development of E. sinensis.

The present study evaluated the effects of magnesium (Mg) on growth, antioxidant capacity, intestinal morphology and ammonia nitrogen resistance in juvenile oriental river prawn, Macrobrachium nipponense. Six semipurified diets (crude protein 401.1 g kg(-1) diet; crude lipid 88.7 g kg(-1) diet) containing Mg levels of 1.1, 1.4, 1.6, 2.1, 2.8 or 4.5 g kg(-1) were formulated. A total of 1080 healthy juvenile prawns (0.151 +/- 0.003 g) were randomly stocked into eighteen 300 L tanks (100 x 80 x 60 cm), each tank with 60 prawns. Each experimental diet was fed to prawns in triplicate twice daily (08:00 and 17:00) for eight weeks. After the feeding trial, 20 prawns from each tank were challenged with 37 mg/L ammonia nitrogen for 96 h, and the hemolymph, hepatopancreas and muscle of the rest of the prawns were collected. Final biomass was higher in prawns fed diets containing 1.6 and 2.1 g Mg kg(-1) compared with those fed the diet with 1.1 g kg(-1). Higher alkaline phosphatase (ALP) activity was obtained in the serum of prawns fed the 2.1 and 2.8 g Mg kg(-1) diets. The highest activities of hepatopancreas superoxide dismutase (SOD), glutathione pemxidase (GSH-Px) and total antioxidant capacity (T-AOC) were observed in prawns fed 1.6-2.8 g Mg kg(-1) of feed, and the lowest hepatopancreas malondialdehyde (MDA) concentrations and serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were found in these treatment groups. Similarly, the prawns fed diets with 1.6 and 2.1 g Mg kg(-1) had significantly lower MDA concentrations and cumulative mortality and higher antioxidant enzyme activities after ammonia nitrogen exposure. The intestinal epithelial cells were closely attached to the membrane in prawns fed the 2.1 g Mg kg(-1) diet, but they were partly detached in those fed the 1.1 and 4.5 g Mg kg(-1) diets. The minimum dietary Mg supplementations of juvenile M. nipponense were determined to be 1.6, 1.9, 2.0 and 2.2 g kg(-1) feed, respectively, using broken-line regression analysis based on the final biomass, SOD, ALT and ALP.

Carbohydrate is commonly used in aquatic organism as the cheapest energy source. However, most aquatic animals are low efficient in utilizing dietary carbohydrate for energy provision. Therefore, improving the utilization efficiency of high carbohydrate by aquatic organisms is important for sustainable aquaculture development. Alpha-lipoic acid (alpha-LA) is a cofactor of key enzymes involved in glucose metabolism. However, its role in regulation of carbohydrate metabolism in aquatic animals is currently unknown. This study investigated the effects of alpha-LA on growth, antioxidant status, hepatopancreas morphology, and carbohydrate metabolism of freshwater prawns Macrobrachium nipponense under two dietary carbohydrate levels. Six diets were formulated using casein and fish meal as the protein sources, fish oil and soybean oil as the lipid sources, and corn starch as the carbohydrate source, at two carbohydrate levels (15% and 30%) and three concentrations of alpha-LA supplementation (0, 700, and 1400 mg/kg). Each experimental diet was fed to juvenile prawns (mean weight 0.050 +/- 0.003 g), twice daily to apparent satiation, in five replicates. In the 15% (low)-carbohydrate groups, weight gain was significantly reduced in prawns fed 1400 mg/kg alpha-LA compared with 0 or 700 mg/kg alpha-LA, but there was no significant effect in the 30% (high)-carbohydrate groups. Survival was significantly higher among prawns fed 700 mg/kg alpha-LA compared with 0 or 1400 mg/kg alpha-LA regardless of the carbohydrate level. The levels of dietary carbohydrate and alpha-LA also significantly affected the activities of key enzymes involved in glycolysis and the citric acid cycle. The activities of hexokinase and pyruvate kinase activities were highest in prawns fed l400 mg/ kg alpha-LA, in both the low- and high-carbohydrate groups. Supplementation with 700 or 1400 mg/kg alpha-LA significantly increased the activities of 6-phosphofructokinase, pyruvate dehydrogenase, and succinate dehydrogenase regardless of the carbohydrate level. The level of malondialdehyde decreased significantly with increased alpha-LA supplementation; in contrast, the levels of superoxide dismutase, glutathione peroxidase, and glutathione were significantly higher in prawns fed 700 or 1400 mg/kg alpha-LA when compare with those fed no alpha-LA supplement. Dietary alpha-LA did not affect the overall morphology of the hepatopancreas, but 1400 mg/kg alpha-LA reduced the number of B (blister-like) cells. Thus, 700 mg/kg alpha-LA supplementation under either dietary carbohydrate level could improve the antioxidant status, carbohydrate metabolism, and morphology of the hepatopancreas in juveniles of M. nipponense. We conclude that alpha-LA supplementation can be used to improve the efficiency of carbohydrate utilization when a 30% carbohydrate diet is used for this prawn.

为探讨动植物蛋白对日本沼虾生长、肌肉组成、抗氧化、TOR信号通路及食欲调节相关基因表达的影响,实验配制了3组等氮等能饲料,分别为鱼粉组(FM)、混合植物蛋白组(豆粕,菜粕,玉米蛋白粉)(PPB)和混合植物蛋白添加氨基酸组(PPB/Aa),投喂饲养日本沼虾8周.结果发现,PPB和PPB/Aa组日本沼虾增重率和摄食率显著低于FM组,而饲料系数显著高于FM组,各组之间成活率和肌肉必需氨基酸组成无显著差异;FM组肝胰腺丙二醛(MDA)含量、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性显著低于PPB组和PPB/Aa组,各组谷草转氨酶(AST)和谷丙转氨酶(ALT)无显著差异,PPB与PPB/Aa组血清碱性磷酸酶(AKP)、酸性磷酸酶(ACP)和ALT的活性均显著高于FM组;与FM组相比,PPB与PPB/Aa组显著降低了雷帕霉素靶蛋白(TOR)、核糖体蛋白S6激酶(S6K)及神经肽(NPY)基因的表达,但各组瘦素(leptin)基因的表达无显著差异.研究表明,鱼粉与混合植物蛋白对日本沼虾肌肉中氨基酸组成无显著影响,但混合植物蛋白源降低了虾的生长和抗氧化能力及TOR信号通路与NPY基因表达,且添加氨基酸不能缓解混合植物蛋白所引起的生长抑制、氧化应激及蛋白质合成和食欲相关基因表达的降低.