Effects of dietary fish oil substitution with blending vegetable oils on growth performance,antioxidant enzyme activities and tissue fatty acid composition of juvenile swimming crab,Portunus trituberculatus

An 8‐week feeding trial was conducted to evaluate the effects of replacement of fish oil (FO) with blending vegetable oils (VOs) on growth performance, antioxidant enzyme activities and fatty acid composition in tissue of swimming crab Portunustrituberculatus. Five isonitrogenous and isolipidic diets were formulated to contain VOs (colza oil: palm oil: linseed oil = 4:2:1) to replace 0 (the control diet), 250, 500, 750 and 1000 g/kg of FO (defined D0, D25, D50, D75, D100). Three hundred juvenile swimming crabs (initial weight 2.34 ± 0.08 g) were randomly stocked and sorted into 300 individual rectangle plastic baskets in three cement pools. Each treatment has three replicates, one replicate has 20 swimming crabs, and each diet fed 60 crabs distributed in 60 baskets. The results indicated that crabs fed the control diet showed significantly higher survival, final body weight, per cent weight gain (PWG), specific growth rate and moulting frequency, crude protein and crude lipid contents in muscles than those fed the D75 and D100 VO diets (p < .05). Crabs fed the D25 VO diet showed significantly higher concentration of triglyceride, low‐density lipoprotein cholesterol and total protein, activities of superoxide dismutase, catalase and glutathione peroxidase (GSH‐Px) in haemolymph than those fed the control diet (p < .05). Fatty acid composition in hepatopancreas was positively correlated with dietary composition. In summary, based on the PWG, the optimal replacement of FO with VOs was estimated to be 250 g/kg. These findings demonstrated that swimming crabs make better use of FO than VOs.     

Effects of dietary fish oil replacement with blended vegetable oils on growth,lipid metabolism and antioxidant capacity of subadult swimming crab Portunus trituberculatus

A 120‐day trial was conducted to assess the effects of dietary fish oil replacement with vegetable oils on growth, lipid metabolism and antioxidant capacity of subadult swimming crab Portunus trituberculatus. Five isonitrogenous and isolipidic diets were formulated to replace 0, 250, 500, 750 and 1000g/kg of fish oil with a mixture of soybean and rapeseed oil (defined as D1–D5), and each treatment had 30 replicate crabs. Dietary fish oil replacement had no significant effects on growth of the crabs, while the D3 had the highest hepatosomatic index and total lipids in hepatopancreas. The triglyceride and lipase activities in hepatopancreas increased significantly with increasing dietary fish oil replacement. The D4 had the highest levels of alkaline phosphatase (ALP) and acid phosphatase (ACP) in the hepatopancreas, as well as the haemolymph ALP, ACP and peroxidase. The highest levels of haemolymph total antioxidant capacity, catalase and malondialdehyde were detected in D1. Total n‐3 polyunsaturated fatty acids levels in hepatopancreas decreased significantly with increasing dietary fish oil replacement. In conclusion, dietary fish oil replacement had no significant effects on growth of P. trituberculatus, and 500g/kg of fish oil replacement could improve antioxidant capacity, but excessive replacement level will enhance lipid accumulation and peroxidation in the hepatopancreas.     

Effect of dietary leucine on growth performance,hemolymph and hepatopancreas enzyme activities of swimming crab,Portunus trituberculatus

An 8‐week feeding trial was conducted to determine the dietary leucine requirement for juvenile swimming crabs reared in cement pools. Six isonitrogenous and isolipidic practical diets (430 g/kg crude protein and 70 g/kg crude lipid) were formulated to contain graded leucine levels which ranged from 16.7 to 26.7 g/kg (dry weight). Each diet was randomly assigned to triplicate groups of 60 juvenile swimming crabs (initial average weight 3.75 ± 0.12 g) that were stocked in rectangle plastic baskets. The results of the present study indicated that dietary leucine levels significantly influenced weight gain (WG) and specific growth ratio (SGR) (p < .05), crab fed the diet containing 22.7 g/kg leucine had significantly higher WG and SGR than those fed the other diets. Feed efficiency and protein efficiency ratio were not significantly affected by the dietary leucine levels (p > .05). Total protein, cholesterol, triglyceride and glucose in serum were significantly affected by the dietary leucine levels. Aspartate aminotransferase (AST) and alanine aminotransferase activities in hemolymph, AST and superoxide dismutase activities in hepatopancreas were significantly affected by dietary leucine levels; moreover, crab fed the 16.7 g/kg leucine diet had higher malondialdehyde in hemolymph and hepatopancreas than those fed the other diets. Crab fed the diet containing 24.9 g/kg leucine had higher phenoloxidase activity in hemolymph than those fed the other diets. Based on two‐slope broken‐line model of SGR against dietary leucine levels, the optimal dietary leucine requirement for growth was estimated to be 22.1 g/kg of the dry diet (corresponding to 51.4 g/kg of dietary protein on a dry weight basis). In summary, findings of this study indicated that dietary leucine could improve growth performance and antioxidant status.     

Dietary arginine requirement of juvenile swimming crab,Portunus trituberculatus

An 8‐week feeding trial was conducted to determine the optimal dietary arginine requirement for juvenile swimming crab Portunus trituberculatus. Six isonitrogenous and isolipidic experimental diets were formulated to contain graded arginine levels which ranged from 15.9 to 33.0 g kg^?1. Each diet was randomly assigned to triplicate groups of 60 juvenile swimming crabs (4.72 ± 0.12 g). The results indicated that dietary arginine had significant effects on weight gain (WG), specific growth rate (SGR), protein productive value, feed efficiency and protein efficiency ratio. Weight gain and SGR significantly increased with the dietary arginine increasing from 15.9 to 27.4 g kg^?1, while with the further increasing from 27.4 to 33.0 g kg^?1, WG and SGR did not increase significantly. Maximum arginine, proline and total essential amino acid contents in muscle were observed in 27.4 g kg^?1 group diet. The swimming crab fed the diet with lower dietary arginine level showed higher AST and lower ALT in the serum. Crab fed with the lower dietary arginine level had significantly lower ALT in the serum than the other groups. Haemolymph indexes were significantly affected by the dietary arginine level except for the cholesterol concentration, and the highest values were all found in 27.4 g kg^?1 group diet. The two slope broken‐line model using SGR showed that the optimal dietary arginine requirement was 27.7 g kg^?1 of the dry matter (56.0 g kg^?1 dietary protein) for juvenile swimming crab.     

Effects of dietary phospholipid and cholesterol levels on growth and fatty acid composition of juvenile swimming crab,Portunus trituberculatus

The objective of this study was to evaluate the effects of different phospholipids (PL) and cholesterol (CH) levels on the growth, moulting and fatty acid composition of juvenile swimming crab, Portunus trituberculatus. Six diets were designed to contain three PL levels (0, 10 and 20 g/kg) and two CH levels (2 and 8 g/kg). Juvenile swimming crabs (3.48 ± 0.02 g/crab) were reared for 8 weeks. The weight gain (WG) was significantly (p < .05) increased by supplementation of 8 g CH/kg of diet. However, no significant interaction between dietary PL and CH levels was found on the growth performance (p > .05). The moulting frequency (MF), protein efficiency ratio (PER) and feed efficiency ratio (FCR) were not significantly (p > .05) affected by the dietary treatments. The serum total cholesterol (TCH) significantly (p > .05) increased with increasing dietary PL level. The C20:4n‐6 and C20:5n‐3 content of the whole body of crabs increased with the addition of PL to the diet containing 2 g/kg CH of diet. An interaction was observed between PL and CH on certain saturated and unsaturated fatty acid concentrations of body.     

Effects of dietary lipid sources on growth performance,lipid metabolism and antioxidant status of juvenile Russian sturgeon Acipenser gueldenstaedtii

Six isonitrogenous and isoenergetic diets were used to test the influence of lipid source on growth performance, antioxidant status and lipid metabolism of juvenile Russian sturgeon, Acipenser gueldenstaedtii. Each diet was supplemented with 90 g kg^?1 of lipid from each of six sources including fish oil (FO), beef tallow (BT), sunflower oil (SO), linseed oil (LO) and equal combinations of FO + SO + BT (FSB) or LO + SO + BT (LSB). After 56 days, fish fed LSB demonstrated highest weight gain, specific growth rate and lowest hepatosomatic index among all groups. The n‐6 polyunsaturated fatty acids (PUFAs) in the whole fish were highest in the SO group, and n‐3 PUFAs were highest in fish fed LO. The fish fed FO contained highest n‐3 highly unsaturated fatty acids. Triglyceride in the serum of fish fed LSB was lowest, but was not significantly different from that in the SO group. Triglyceride in the serum of fish fed FO and BT was highest among all groups. Lipase, malate dehydrogenase and lipoprotein lipase activities were highest in fish fed LSB. Serum malondialdehyde in fish fed LSB was significantly lower than in fish fed FO or SO, but no significant differences were found among fish fed LSB, BT, LO or FSB. Fish fed LSB showed higher catalase activity and total antioxidant capacity than fish fed FO or FSB. This study indicates that linseed, sunflower oil and BT mixed oil are a suitable lipid source and can benefit growth performance and antioxidation in juvenile sturgeon.     

Effects of different dietary lipid sources on tissue fatty acid composition,serum biochemical parameters and fatty acid synthase of juvenile mud crab Scylla paramamosain (Estampador 1949)

A 6‐week study was conducted to determine the effects of different lipid sources in pelleted diets on juvenile mud crab Scylla paramamosain. Five isonitrogenous and isolipidic diets containing 8% level of fish oil (FO), lard (LD), safflower oil (SO), perilla seed oil (PO) or mixture oil (MO; V_FO:V_SO:V_PO = 1:1:1), and a live food of marine bivalve Potamocorbula rubromuscula as the control diet (CF), were fed to groups of 25 juvenile crabs (average initial weight 7.4 g, carapace width 3.5 cm) in triplicate. The results showed that crabs fed MO had the highest survival (P < 0.05). The moisture content was significantly higher in crabs fed LD, SO and PO (P < 0.05). Crabs fed SO exhibited the lowest crude protein and lipid (P < 0.05). Ash contents were obviously lower in LD group (P < 0.05). Highest total lipid in the hepatopancreas and muscle was in LD and FO group respectively. Glucose, total cholesterol and low‐density lipoprotein were higher while high‐density lipoprotein was lower (P < 0.05) in LD group. Tissue fatty acid compositions were consistent with those in diets. FO and MO diets had the same depression effect like CF on fatty acid synthase activity and mRNA expression in the hepatopancreas. The results of this study indicated that FO and mixed oil are suitable for preparation of pelleted diets with better effects for juvenile S. paramamosain compared with live food, and the ratio of n‐6/n‐3 fatty acids in pelleted diets must be <1.     

三疣梭子蟹胚胎发育过程中主要生化组成的变化及其能量来源

系统研究了三疣梭子蟹(Portunus trituberculatus)胚胎发育过程中胚胎体积、单卵干重、湿重、蛋白质、脂肪、碳水化合物的变化规律,探讨胚胎发育过程中能量来源和消耗规律。结果表明,三疣梭子蟹胚胎发育过程中,胚胎体积持续增加,由受精卵时的(24.5±1.72)×106μm3增加到孵化前的(39.2±2.8)×106μm3(P<0.01);胚胎体积增加主要发生在胚胎发育后期。胚胎发育过程中单卵中水分含量呈上升趋势(P<0.05),水分绝对量由受精卵的(19.88±1.65)μg上升到心跳期的(28.82±1.77)μg,单卵水分含量升高了44.97%,故单卵湿重显著上升(P<0.05)。整个胚胎发育过程中单卵干重下降了4.64%。胚胎发育过程中单卵中的蛋白质、脂肪下降显著,分别减少了(1.97±0.35)μg和(1.99±0.45)μg,脂肪含量下降幅度为50.48%,而蛋白质含量下降幅度为23.48%;三疣梭子蟹胚胎发育过程中能量主要由脂类提供(71.32±20.46)%,其次由蛋白质提供(27.13±4.29)%,脂类和蛋白质分别充当了不同胚胎时期的主要能量来源,胚胎中的能量消耗主要发生在卵裂期、原肠期和心跳期。     

饲料中蛋白水平对三疣梭子蟹雌体生长、卵巢发育和生化组成的影响

本研究配制蛋白水平分别为32.16％、36.13％、39.59％和41.24％的等脂等能配合饲料(分别记为饲料1～4),对初始体重为(10.98±0.28)g的三疣梭子蟹(Portunus trituberculatus)雌体进行池塘养殖120 d,以探究饲料蛋白水平对三疣梭子蟹雌体生长、卵巢发育和生化组成的影响.结果...     

Effects of dietary DHA/EPA ratios on growth performance,survival and fatty acid composition of juvenile swimming crab (Portunus trituberculatus)

This study was conducted to investigate the effects of dietary docosahexaenoic to eicosapentaenoic acid (DHA/EPA) ratios on growth performance, survival and fatty acid composition of juvenile swimming crab (Portunus trituberculatus). Four isonitrogenous and isoenergetic experimental diets were formulated to contain different DHA/EPA ratios (0.70, 0.84, 1.06 and 1.25). There were three replicates (15 crabs per replicate) for each diet treatment. The crabs were fed (about 6–8% body weight) twice daily for 8 weeks. A good growth performance and feed utilization were observed in swimming crabs fed the diets with DHA/EPA ratios of 0.70 and 0.84. Crabs fed diet with 0.70 DHA/EPA ratio showed a significantly higher weight gain (WG) compared with the crabs fed the diet with DHA/EPA ratio of 1.25 (P < 0.05). The result of this study showed that the survival increased with decreasing the ratio of DHA/EPA. The DHA/EPA ratios in polar lipid from tissues were influenced by the dietary DHA/EPA ratios. Results of this study indicated that the growth performance and survival of juvenile swimming crab are correlated to the DHA/EPA ratio in the diets, and the best growth performance and survival were achieved with the ratios of 0.70–0.84.     

Effects of different dietary lipid sources on growth performance,body composition and lipid metabolism‐related enzymes and genes of juvenile golden pompano,Trachinotus ovatus

Three groups of juvenile golden pompano, Trachinotus ovatus (54.75 ± 0.25 g), were each fed one of three diets containing different lipid sources: fish oil (FO), soybean oil (SO) and lard oil (LO). Fish were reared in sea cages for 8 weeks, and the fish fed the FO diet had significantly higher specific growth rate (SGR) but lower condition factor (CF) than the other treatments. The fatty acid (FA) composition of whole‐body lipids was closely correlated with those in the diets. Although no differences can be found in hepatic fatty acid synthase (fasn) activity, the carnitine palmitoyl transferase 1 (cpt1) activity in fish fed the FO diet was significantly higher compared with other treatments. In addition, the relative gene expression of lipid metabolism‐related enzymes, such as cpt1, fas, apolipoprotein B100 (apoB100), delta‐6 fatty acyl desaturase (fadsd6) and fatty acid‐binding protein 1 (fabp1), was also influenced by the different dietary lipid sources. Serum triglyceride (TG) and glucose content in fish fed the LO and FO diets were significantly higher than those in the SO group. Accordingly, it can be concluded that FO could not be completely replaced by SO or LO in golden pompano diets. The lipid sources of a diet could impose significant influence on body condition factor and hepatic lipid metabolism of golden pompano.     

Effects of low salinity stress on immune response and evaluating indicators of the swimming crab Portunus trituberculatus

The purpose of the present study was to investigate the effects of salinity stress on immune responses and evaluating indicators in swimming crab Portunus trituberculatus. The crabs (150 ± 8.5 g in body weight) were exposed to different salinities as 21, 26 and 31‰ (control) for 6 days. The results showed the total haemocyte counts (THC) and prophenoloxidase (proPO) activity in the haemocytes decreased significantly in the treatment groups after 6 hr, and reached the lowest levels at 12 hr. The phenoloxidase (PO) activity in the plasma increased significantly and peaked at 12 hr, then recovered to control level after 24 hr. The phagocytic per cent of haemocyte, antibacterial and bacteriolytic activities in the plasma decreased significantly in the treatment groups, and reached the lowest level at 12 hr, then recovered to control level after 72 hr. The dopamine (DA) and 5‐hydroxytryptamine (5‐HT) contents in the plasma increased significantly and peaked at 12 hr, then recovered to control level, while the noradrenaline (NE) content in the plasma had no significant change throughout the duration of the experiment. The DA and 5‐HT receptors were significantly up‐regulated in the treatment groups. The highest value of mRNA expression of DA and 5‐HT receptors occurred at 12 hr and recovered to control level after 24 hr. In addition, the cAMP and protein kinase A (PKA) contents in the haemocytes increased significantly and peaked at 12 hr, then recovered to control level after 72 hr. The phospholipase C (PLC) and protein kinase C (PKC) contents in the haemocytes increased significantly and peaked at 12 hr, then resumed to control level after 24 hr. These results speculated that biogenic amine (DA and 5‐HT) is likely to play an important role in immune modulation via cAMP/PKA signalling pathway or PLC/PKC signalling pathway when P. trituberculatus is exposed to low salinity and these results will provide scientific data for immune evaluation.     

饲料脂肪水平对匙吻鲟生长、体组成、消化酶活性、血清生化及抗氧化性能的影响

为探讨饲料脂肪水平对匙吻鲟生长、体组成、消化酶活性、血清生化指标、抗氧化性能的影响,将鱼油与豆油等比例混合作为脂肪源,配制成脂肪水平分别为3.01%、5.12%、7.14%、9.35%和11.64%的5种等氮膨化实验饲料,将270尾匙吻鲟[初始体质量（81.38±0.14）g]分为5组,每组3个重复,每个重复18尾鱼,在室外养殖系统微流水养殖56 d。结果显示：①随着饲料脂肪水平的升高,实验鱼增重率（WGR）、特定生长率（SGR）、饲料转化率、蛋白质效率（PER）、肝体比（HSI）及肥满度（CF）均呈现先升高后下降的趋势,回归分析确定,当SGR达到最大值时,饲料脂肪水平为7.88%;当PER达到最大值时,饲料脂肪水平为9.47%;②实验鱼肌肉、肝脏粗脂肪含量随饲料脂肪水平上升而上升,11.64%组显著高于3.01%、5.12%和7.14%组,全鱼及肌肉粗蛋白含量随饲料脂肪水平增加呈上升趋势,3.01%组显著低于其他组,7.14%、9.35%组之间没有显著性差异;③实验鱼肌肉和肝脏主要脂肪酸组成与饲料脂肪酸组成相关,随着饲料脂肪水平的升高,肌肉和肝脏中n-6多不饱和脂肪酸（n-6 PUFA）比例升高,n-3/n-6降低,肝脏中饱和脂肪酸（SFA,C16：0、C18：0）随着饲料脂肪水平上升而下降;单不饱和脂肪酸C18：1n-9呈先上升后下降趋势;肌肉和肝脏脂肪酸组成中,组间n-3高不饱和脂肪酸（n-3 HUFA）、n-3 PUFA比例没有显著性差异;④7.14%组肠蛋白酶活性显著高于9.35%组,肝脏淀粉酶活性在脂肪水平7.14%以上组趋于稳定,肝脏蛋白酶和脂肪酶活性在组间没有显著性差异;⑤血清总蛋白（TP）、白蛋白（ALB）及球蛋白（GLOB）浓度随饲料脂肪水平升高呈上升趋势,血清总胆固醇（TC）、高密度脂蛋白胆固醇（HDL-C）浓度11.64%组显著高于3.01%组,谷丙转氨酶（ALT）和谷草转氨酶（AST）活性未受到饲料脂肪水平的影响;⑥饲料脂肪水平的上升可以显著提高血清超氧化物歧化酶（SOD）活性,回归分析得出当SOD活性达到最大值时,饲料脂肪水平为9.69%;但对谷胱甘肽过氧化物酶（GSH-Px）活性、丙二醛（MDA）含量没有显著影响;肝脏SOD活性11.64%组显著低于其他各组,GSH-Px活性9.35%组显著高于3.01%、5.12%、7.14%组,与11.64%组没有显著性差异,GSH、MDA含量在组间没有显著性差异。通过对饲喂不同脂肪水平饲料实验鱼生长、饲料利用率、鱼体组成、消化酶活性及鱼体健康等方面指标综合分析,认为本实验条件下,匙吻鲟适宜脂肪水平为7.88%~9.69%。     

Effect of dietary lipid levels on growth performance,fatty acid profile and enzymatic activity of juvenile swimming crab,Portunus trituberculatus

The main objective of this investigation was to study the lipid requirements of the early juvenile (C1) swimming crab (Portunus trituberculatus) based on growth performance, survival, moulting and fatty acid profile. Four test diets were formulated with graded lipid levels (3.63%, 6.70%, 10.72% and 13.91%). Each diet was fed to 4 replicates of crabs (30 crabs per replicate initial weight (8.4 ± 0.1 mg). In this study, crabs fed diets with 13.91% lipid had significantly (p < 0.05) higher survival than crabs fed with 3.63% lipid, but no significant (p > 0.05) improvement of survival was observed when dietary lipid increase from 6.70% to 13.91%. Crabs fed diets with 10.72% and 13.91% lipid had significant higher weight gain(WG) than crabs fed with 3.63% lipid. While crabs fed with diets containing 6.70%, 10.72% and 13.91% lipid showed no significant (p > 0.05) difference in weight gain(WG). Moreover, the lowest moulting number was observed in crabs fed diets with 3.63% lipid, but there was no significant difference (p > 0.05) among other groups. The content of LC‐PUFA and DHA in the crabs fed diets with 3.63% lipid was significant (p < 0.05) lower compared to other groups. But there was no significant (p > 0.05) difference in EPA and ARA content among all groups. The activity of lipase increased as dietary lipid level increased (from 6.70% to 10.72%). However, beyond 10.72%, a significant (p < 0.05) decreased in lipase activity was observed. The regression analysis of weight gain data indicated that crab fed diet containing 10.47% lipid level is considered as optimum lipid level for its maximum growth and moulting process.     

Comparison of immune responses and antioxidant status of different generations of growth‐selected Portunus trituberculatus families

The purpose of this study was to investigate the effects of inbreeding on the immune responses and antioxidant status of Portunus trituberculatus juveniles. Results showed that inbreeding affected the total haemocyte count, and phagocytic, pro‐phenoloxidase (propo), phenoloxidase and antibacterial activities decreased after the seventh generation. Antioxidant status showed a similar pattern: total antioxidant capacity, superoxide dismutase (SOD) activity and GSH/GSSG in the cell‐free haemolymph and hepatopancreas decreased, while catalase activity in the cell‐free haemolymph increased (P < 0.05). There were no significant differences in α₂‐macroglobulin and bacteriolytic activities in the cell‐free haemolymph and glutathione peroxidase activity in the cell‐free haemolymph and hepatopancreas among nine inbreeding generations. Gene expression levels of proPO and crustin in haemocytes and SOD in haemocytes and hepatopancreas also decreased significantly as the inbreeding generations increased. The results suggest that a high level of inbreeding could severely reduce the physiological health of P. trituberculatus. Our obtained data would be particularly useful for P. trituberculatus breeding programmes.     

不同脂肪源对黄颡鱼幼鱼生长性能、体成分、血清生化指标、体组织脂肪酸组成及抗氧化能力的影响

为研究不同脂肪源对黄颡鱼幼鱼生长性能、体成分、血清生化指标、体组织脂肪酸组成及抗氧化能力的影响,进行为期8周的养殖实验。实验配制了4种分别添加有椰子油(CO)、苏子油(PO)、葵花籽油(SO)、鱼油与葵花籽油1∶1混合油(FO/SO)的等氮等脂的饲料,喂养平均初始体质量为(1.52±0.00)g的黄颡鱼幼鱼。实验结果显示:不同脂肪源对黄颡鱼终末体质量(FBW)、增重率(WGR)、特定生长率(SGR)和成活率(SR)均无显著影响,对饲料系数(FCR)影响显著,各组SR均在95%以上。各组间的肝体比(HSI)、肥满度(CF)均有显著性差异,而脏体比(VSI)和肠脂比(IPR)无显著性差异。HSI和CF均以鱼油与葵花籽油1∶1混合油(FO/SO)组最高,葵花籽油(SO)组最低。黄颡鱼的鱼体水分、粗蛋白和灰分不受饲料脂肪源的影响,而椰子油(CO)组的粗脂肪含量显著高于其他3组,为10.51%,剩余3组间无显著性差异。饲料中脂肪源对黄颡鱼肌肉、肝脏组织脂肪酸组成和含量影响显著,并且肌肉和肝脏中脂肪酸含量变化与饲料中相应脂肪酸含量变化基本一致,椰子油(CO)组组织中饱和脂肪酸(SFA)含量最高,苏子油(PO)组组织中亚麻酸(ALA)和n-3 PUFA含量最高,葵花籽油(SO)组组织中亚油酸(LA)和n-6 PUFA含量最高,而鱼油与葵花籽油1∶1混合油(FO/SO)组组织中脂肪酸较为均衡。黄颡鱼血清中的总蛋白(TP)、白蛋白(ALB)、球蛋白(GLOB)、白蛋白/球蛋白(A/G)、谷草转氨酶(AST)、总胆固醇(CHOL)、甘油三酯(TG)、血糖(GLU)、肌酸激酶(CK)含量不受饲料脂肪源的影响。各组黄颡鱼肝脏中超氧化物歧化酶(SOD)、丙二醛(MDA)、谷胱甘肽S转移酶(GST)活性有显著差异。椰子油(CO)组的SOD和GST活性最高,而MDA含量最低。研究表明,在添加豆油的基础上,椰子油、苏子油、葵花籽油和鱼油与葵花籽油1∶1混合油都可以用作黄颡鱼饲料的脂肪源;证实了鱼体组织中脂肪酸组成基本可以反映饲料脂肪酸组成,并且说明了黄颡鱼具有延长和去饱和ALA和LA的能力。     

iTRAQ‐based identification of differentially expressed proteins related to growth in the swimming crab,Portunus trituberculatus

The swimming crab, Portunus trituberculatus, is an important farmed species in China, and it has been studied extensively, which requires more information on its genetic background. To date, information on the proteomics of P. trituberculatus is scarce. In this study, we used isobaric tags for relative and absolute quantitation (iTRAQ)‐based proteomics to investigate growth regulation in P. trituberculatus. Total proteins were isolated from five tissues (eyestalk, gill, heart, hepatopancreas and muscle). Equal quantities of protein from each tissue were pooled at the proteome level using the iTRAQ method. A total of 961 proteins were identified using liquid chromatography coupled with tandem mass spectrometry and de novo sequencing data. Using a 1.2‐fold change in expression as a physiologically significant benchmark, 30 differentially expressed proteins (DEPs) were found to undergo differential expression related to the growth of P. trituberculatus, and most of the growth‐related proteins, including those involved in metabolism, immune responses, DNA duplication and protein synthesis, were upregulated, indicating that conservation of energy is an important strategy to cope with growth. There was a high consistency between the expression levels determined using iTRAQ and mRNA, highlighting the high reproducibility of our proteomic approach and its great value in elucidating the molecular mechanisms of P. trituberculatus.     

不同脂肪源饲料对中华绒螯蟹幼蟹生长、消化酶活力和脂肪酸组成的影响

选用初始体重为(2.15±0.10)g的中华绒螯蟹(Eriocheir sinensis)雄性幼蟹,随机分为5组(每组12只幼蟹),饲喂100%鱼油组(简称F1组)、100%豆油组(F2组)、100%亚麻油组(F3组)、50%鱼油+50%豆油组(F4组)、50%鱼油+50%亚麻油组(F5组)不同脂肪源配制的5种等氮等能饲料。实验蟹单个体养殖,实验周期为112 d。结果表明,F5组体重、增重率和特定生长率都显著高于其他饲料组(P0.05),各组的蜕壳间隔和肝胰腺指数没有显著差异(P0.05)。肝胰腺组织消化酶活力测定结果表明,F1组幼蟹肝胰腺的类胰蛋白酶活力显著高于其他各组(P0.05);F3组的胃蛋白酶活力显著高于其他各组(P0.05);F1组、F2组和F4组的脂肪酶活力显著高于其他两组(P0.05);各组的淀粉酶活力差异不显著(P0.05)。脂肪酸测定结果表明,肝胰腺和肌肉中的亚油酸(LOA)(C18:2n-6)、亚麻酸(LNA)(C18:3n-3)、EPA(C20:5n-3)和DHA(C22:6n-3)等主要脂肪酸含量与饲料脂肪酸组成呈正相关关系,F1组的高度不饱和脂肪酸(HUFA)含量显著高于其余各组(P0.05),F2组的LOA含量显著高于其余各组(P0.05),F3组的LNA含量显著高于其余各组(P0.05)。本研究结果表明,以50%的豆油或亚麻油替代鱼油能促进中华绒螯蟹幼蟹的生长,但可能使幼蟹的成活率降低。以豆油或亚麻油替代鱼油会影响幼蟹胰蛋白酶、胃蛋白酶和脂肪酶的活力和肝胰腺、肌肉脂肪酸组成。