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291.
This study evaluates the inclusion of lycopene in the commercial diet for Nile Tilapia exposured to a stressor. For 60 days, fish diet was supplemented with lycopene (600 mg kg?1 diet) and at the end, subjected to confinement for 90 min. Zootechnical parameters (weight gain, specific growth rate and intake), hormonal (cortisol level), biochemical {enzyme activity and lipid peroxidation level [thiobarbituric acid (TBARS)]} and physical (instrumental colour) parameters were also evaluated. Supplementation with lycopene did not alter zootechnical parameters. In unconfined fish, catalase (CAT) activity was reduced in the white muscle of fish fed with lycopene; however, in red muscle, it was not altered. In fish under confinement, plasma cortisol increased as well as CAT, glutathione reductase (GR) and lactate dehydrogenase (LDH) activity in both muscles. Lipid peroxidation of the fillet also displayed higher values. However, the lycopene supplementation abolished the effects of confinement available through cortisol levels, remaining unchanged in the above parameters, activity of CAT, GR and LDH in both muscles and TBARS content of the fillet; in addition, it did not induce alteration of fillet coloration. Inclusion of lycopene in commercial feed reduces the impact of confinement and does not alter the zootechnical parameters; additionally, no modification of the fillet colour from juvenile Nile tilapia was observed.  相似文献   
292.
An 8‐week feeding trial was conducted to determine the effect of dietary conjugated linoleic acid (CLA) on growth performance, muscle fatty acid profile, hepatic intermediary metabolism and antioxidant responses in genetically improved farmed Tilapia (GIFT) strain of Oreochromis niloticus (initial body weight: 42.6 ± 0.4 g, mean ± standard deviation). Three replicated groups of GIFT strain of Nile tilapia were hand‐fed to satiation, twice a day, with the diets in which CLA oil, containing mainly the bioactive cis‐9, trans‐11 and trans‐10, cis‐12 isomers, was included at 0 (control), 0.5%, 1%, 1.5%, 2% and 2.5%, respectively, at the expense of fish oil to maintain the constant lipid and energy levels. Growth performance and feed utilization showed no significant differences among the treatments (P > 0.05). The dietary inclusion of CLA modified total percentages of the main groups of fatty acids. Increasing saturated fatty acid content and reduced mono‐unsaturated fatty acid contents in muscle were observed with increasing dietary CLA inclusion (P < 0.05). Total n‐3 fatty acids and total polyunsaturated fatty acids tended to decline with increasing dietary CLA levels (P < 0.05), but n‐6 fatty acids showed no significant differences among the treatments (P > 0.05). Dietary CLA supplementation resulted in the significant increase in the trans‐10, cis‐12 and cis‐9, trans‐11 CLA isomers in muscle (P < 0.05) and also significantly influenced several hepatic enzymatic activities, such as succinate dehydrogenase, lactate dehydrogenase, malic dehydrogenase, lipoprotein lipase and hepatic lipase activities (P < 0.05). Reduced superoxide dismutase and glutathione peroxidase activities, and the decline in malondialdehyde levels were observed in fish fed the CLA‐supplemented diets (P < 0.05), indicating that dietary CLA supplementation showed a powerful antioxidant effect for this fish species. Our study was the first report involved in the effect of dietary CLA inclusion on hepatic intermediary metabolism and antioxidant responses in fish, which could be used as indicators of nutritional and physiological status of the fish species.  相似文献   
293.
不同循环饥饿投喂模式对尼罗罗非鱼补偿生长的影响   总被引:4,自引:1,他引:3  
李建  王琨  陈建春  叶继丹 《水产学报》2014,38(6):869-876
为了探讨尼罗罗非鱼对不同循环饥饿投喂模式的补偿生长效应,本实验分别采用每天投喂(S0)及饥饿1 d+投喂3 d(S1F3)、饥饿1 d+投喂5 d(S1F5)、饥饿1 d+投喂7 d(S1F7)、饥饿2 d+投喂3 d(S2F3)、饥饿2 d+投喂5 d(S2F5)和饥饿2 d+投喂7 d(S2F7)6种不同的循环投喂模式,用含33%蛋白质和8%脂肪的饲料饲养尼罗罗非鱼(均重13.50 g),饲喂期为43 d。结果显示,S0组的增重率(806.74%)最高,与S1F3、S1F5和S1F7组差异不显著,但分别比S2F3、S2F5和S2F7组显著提高40.3%、33.6%和10.4%;S0组的特定生长率最低(5.36%),显著低于其他各组;与对照组相比,采用循环投喂模式没有改善饲料转化率和蛋白质效率,但却能明显提高日摄食率;各实验处理组肝体比、脏体比、肥满度、鱼体灰分含量、肌肉RNA/DNA比值及血清总胆固醇、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇和尿素氮含量与对照组差异不显著;S1F3、S1F5和S1F7组鱼体蛋白质和脂肪含量、血清甘油三酯含量及血清谷丙转氨酶和谷草转氨酶活性与S0组差异不显著,但S2F3、S2F5和S2F7组鱼体蛋白质和脂肪含量及血清甘油三酯含量显著低于S0组,血清谷丙转氨酶和谷草转氨酶活性显著高于S0组。研究表明,尼罗罗非鱼在S1F3、S1F5和S1F7模式下获得了完全补偿生长,而在S2F3、S2F5和S2F7模式下仅获得了部分补偿生长,且均是通过提高恢复投喂期间的摄食量来实现补偿生长。在获得完全补偿生长的3组中,S1F3组的实际投喂天数最短,仅为33 d,比每天投喂模式缩短了23.3%,因此在本实验条件下,饥饿1 d+投喂3 d是最佳的循环饥饿投喂模式。  相似文献   
294.
吉富罗非鱼对饲料中泛酸的需要量   总被引:1,自引:1,他引:0  
黄凤  蒋明  文华  吴凡  刘伟  田娟  杨长庚 《水产学报》2014,38(9):1530-1537
选用初始体质量为(79.4±1.6)g吉富罗非鱼270尾,随机分成6组(每组3重复,每重复15尾),养殖于500 L养殖桶中,分别饲喂泛酸含量为0.5、4.8、9.5、18.2、36.3和74.4 mg/kg纯化饲料12周,研究确定其对泛酸的需要量。结果表明,随着饲料泛酸含量增加,吉富罗非鱼增重率、肝脏和肌肉泛酸含量均呈先线性增加后稳定的趋势;肥满度和肝体比呈先增加后降低的趋势,均以4.8 mg/kg组最高。全鱼水分含量先降低后增加,全鱼脂肪含量呈现与水分含量相反的趋势。肝总脂含量显著降低,添加组显著低于未添加组(P0.05)。血清高密度脂蛋白含量随着饲料泛酸含量的增加而显著增加(P0.05)。折线回归分析结果表明,吉富罗非鱼(80~350 g)获得最佳生长时对饲料泛酸需要量为10.5 mg/kg,饲料中12.6和13.5mg/kg泛酸可以分别使肝脏和肌肉泛酸累积量达到最大。  相似文献   
295.
为考察吉富罗非鱼(GIFT,Oreochromis niloticus)对饲料中锌的需要量,以蛋氨酸锌为锌源,配制锌添加水平分别为0,10,20,40,80,160 mg/kg的6组等氮等脂饲料(实测值分别为9.98,21.47,33.75,56.03,88.16,172.54 mg/kg),饲喂初始体质量为(84.44±3.04)g的吉富罗非鱼,试验鱼分为6组,每组3个重复,每个重复20尾鱼,养殖周期为10周。结果显示,随着饲料中锌含量的增加,吉富罗非鱼的增重率、特定生长率先显著升高,在锌含量达到33.75 mg/kg后趋于稳定,添加锌显著降低了饲料系数,提高了成活率。饲料锌含量对全鱼水分、粗蛋白及灰分含量无显著影响,显著降低了全鱼粗脂肪含量。饲料中添加锌对血清总胆固醇含量无影响,显著提高了血清碱性磷酸酶的活性,碱性磷酸酶活性在锌含量达到33.75 mg/kg后趋于稳定,血清甘油三酯含量,乳酸脱氢酶、谷草转氨酶和谷丙转氨酶活性则呈下降趋势。饲料锌含量显著影响脊椎骨、全鱼和肝脏锌的含量,脊椎骨和全鱼锌含量先线性上升,在锌含量达到56.03 mg/kg后趋于稳定,各组的肌肉锌含量无显著差异。以增重率、骨骼锌和全鱼锌含量为评价指标,根据折线回归分析得出,以蛋氨酸锌为添加锌源,吉富罗非鱼对饲料中锌的需要量分别为32.37、55.67和56.13 mg/kg。  相似文献   
296.
Streptococcus agalactiae is an emerging pathogen of fish and has caused significant morbidity and mortality worldwide. The main objective of this study is to assess whether pathogenic differences exist among isolates from different geographic locations. Nile tilapia (Oreochromis niloticus L.) were administered an intraperitoneal injection of suspension containing USA, Brazil, Honduras, Israel, or Kuwait S. agalactiae isolates at concentrations ranging from 102 to 107 cfu mL?1. The LD50 values 7 days after challenge were as follows: USA (1.0 × 102 cfu mL?1), Brazil (1.5 × 103 cfu mL?1), Honduras (6.8 × 103 cfu mL?1), Israel (1.0 × 104 cfu mL?1) and Kuwait (7.2 × 105 cfu mL?1). Fish from all groups exhibited lethargy, anorexia, exophthalmia, corneal opacity, erratic swimming, petechiae and mortality. Opercular clearing and ascites were only found after infection with certain geographic isolates. The findings in this study indicate that S. agalactiae isolates of different geographic origin can cause significant mortalities after experimental challenge and can have different pathogenic capacities. Isolates from the Americas (USA, Brazil and Honduras) were more pathogenic to Nile tilapia than isolates from the Middle East/Asia (Israel and Kuwait).  相似文献   
297.
The combined effects of temperature and salinity on the yolk utilization of sac fry in Nile tilapia (Oreochromis niloticus) were investigated using central composite experimental design and response surface approach. Based on the preliminary trials, temperature was determined to range from 22 to 34°C, and salinity ranging from 2 ppt to 10 ppt. The utilization was mensurated in terms of yolk sac volume. Results showed that the linear effects of temperature and salinity on the yolk utilization was significant (P < 0.01); the quadratic effects of and the interaction between the two factors were significant (P < 0.05); temperature was more important than salinity in influencing the yolk utilization. The model equation of yolk sac volume towards temperature and salinity was established. From those high R2 values, the model had excellent goodness of fit to experimental data and could be applied for predictive purpose. What with the production cost, it is suggested that the temperature/salinity combination, i.e. 28–30°C/4–6 ppt, be employed during the period of sac fry rearing, in which the yolk utilization was on average 98.6%.  相似文献   
298.
尼罗罗非鱼卵黄脂磷蛋白的分离纯化与性质鉴定   总被引:1,自引:1,他引:0  
采用Sephacryl S-300过滤层析和DEAE-Sepharose Fast Flow离子交换层析相结合的方法从尼罗罗非鱼(Oreochromis niloticus)成熟卵子匀浆液中分离纯化出了一种高分子量的蛋白。该蛋白能被Schiff试剂、甲基绿和苏丹黑B着色,Western blot显示能被金鱼卵黄脂磷蛋白(lipovitellin,Lv)多克隆抗血清特异性识别,在非变性条件下分子量约为560 k D,在SDS变性条件下分子量约为112 k D,结果表明分离纯化的蛋白是一种含有糖、磷、脂基团的蛋白,符合鱼类Lv的性质,且与金鱼Lv有免疫交叉反应,从蛋白的性质和免疫原性以及分子量大小等角度判断,本研究获得的高纯度蛋白为尼罗罗非鱼卵黄脂磷蛋白;纯化的罗非鱼Lv在反复冻融、37℃及60℃处理条件下均未出现降解,表明罗非鱼Lv比鱼类卵黄原蛋白(Vitellogenin,Vtg)更为稳定。研究结果为罗非鱼Lv抗体的制备奠定了基础。  相似文献   
299.
The effect of various dietary starch to proteins ratios (STA/P) on growth performance, oxidative status and liver enzyme activities involved in intermediary metabolism in juvenile Nile tilapia was evaluated. Four isocaloric‐practical diets (12.73 MJ kg?1 digestible energy) with increasing STA/CP ratios were formulated. These were designated D0 (344 g crude protein (CP) and 163.5 g starch (STA) kg?1), D1 (310 g CP and 243 g STA kg?1), D2 (258 g CP and 322 g STA kg?1) and D3 (214 g CP and 401 g STA kg?1). Each diet was fed to triplicate groups of 60 fish (2.7 g) for 45 days. Compared with the control diet (D0), significantly (P < 0.05) depressed growth and feed efficiency were observed only in the groups fed on diet D3. The activities of hepatic enzymes involved in glycolysis and lipogenesis pathways were significantly enhanced in groups fed on diet D3 compared with other diets. A significant (P < 0.05) increase in catalase activity was detected only in groups fed on diet D3. Similarly, a significant (P < 0.05) enhancement in superoxyde dismutase, glutathione S‐transferases and glutathione peroxidise was observed in groups fed on diets D2 and D3 compared with other diets. Results demonstrate the ability of juvenile Nile tilapia to spare protein by dietary carbohydrate.  相似文献   
300.
After being shifted to a new diet, time related alterations in digestibility, faecal waste production and faeces recovery in Nile tilapia were assessed in relation with dietary ingredient composition. Four experimental diets were formulated according to a 2 by 2 factorial design: two starch inclusion levels (20 or 40%) and two maize starch types (native versus gelatinized). After introduction to the experimental diets, faeces were collected weekly from Week 2 till 6 using settling tanks. Digestibility of ash, organic matter and dry matter increased with time (P < 0.001). For organic and dry matter the time related alteration in digestibility were different between both starch types (P < 0.05). All faecal waste characteristics altered with time (P < 0.01). The incline in faeces recovery with time was affected by starch type (P < 0.01); being the largest at the 40% gelatinized maize diet. In conclusion, the minimal length of the adaptation period in digestibility studies for obtaining unbiased digestibility estimates is dependent on diet composition, in this study with Nile tilapia 4 weeks for diets with gelatinized starch and 6 weeks with native starch.  相似文献   
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