蓝曼龙配合饲料中最适蛋白含量的初步研究

配制6种不同蛋白质水平(21%,25%,29%,32%,36%,40%)的饲料,在水温为(26±0.5)℃的条件下对(2.37±0.10)g的蓝曼龙幼鱼进行了50d的喂养实验。每个处理设3个重复,每个重复20尾鱼。结果表明:饲料中不同蛋白质水平对蓝曼龙的特定生长率(SGR)、饲料转化率(FCE)和蛋白质效率(PER)均产生显著影响(P<0.05)。在饲料蛋白质含量为21%～29%时,特定生长率随饲料蛋白含量增加呈升高趋势;在饲料蛋白质含量为29%～36%时,特定生长率随饲料蛋白含量增加呈下降趋势。通过折线模型可知,在该实验条件下以特定生长率为指标蓝曼龙饲料的最适蛋白质含量约为28.76%。     

美洲鲥幼鱼饲料中蛋白质的适宜含量

为研究饲料中不同蛋白质含量对美洲鲥幼鱼生长的影响,设置了蛋白质含量分别为35%、40%和45%的3组实验,经过41d的试验得出:蛋白质含量为40%的饲料组,幼鱼的增重率、特定生长率最高(P<0.05);蛋白质含量为40%组和45%组的蛋白质效率和饲料转化率无显著差异(P>0.05),但均高于35%组(P<0.05)。     

翘嘴鲌鱼种饲料中脂肪适宜水平的初步研究

以鱼粉和酪蛋白为蛋白源,以鱼油和豆油的混合物(1︰1)为脂肪源,配制7种等氮不同脂肪水平(1.82%dm~15.02%dm)的试验饲料,饲养平均体重为2.85±0.15g的7组翘嘴鲌隔冬鱼种30d。试验结果表明,翘嘴鲌鱼种饲料中脂肪水平对鱼体生长、饲料系数和蛋白质校效率均有显著的影响(p<0.05)。饲料中适宜的脂肪水平为6.48%~8.78%。     

暗纹东方魨幼鱼对蛋白质的最适需要量

以白鱼粉为蛋白源设计了6个不同蛋白质水平(35%,40%,45%,50%,55%,60%)的等能饲料,采用室内水泥池养殖,在水温为24～26℃条件下对暗纹东方鲀幼鱼进行了12周的生长实验以确定其最适蛋白质需要量.增重率和饲料效率随着蛋白质水平的增加而上升,50%试验组的鱼体增重显著高于35%、40%和45%试验组(P＜0.05),蛋白质含量高于50%以后增重不再有显著变化(P＞0.05).蛋白质效率总体上随着蛋白质水平的增加趋于降低,但在35%、40%和50%试验组之间无显著差异(P＞0.05).采用折线模型测算出暗纹东方鲀幼鱼获得最大增长和对饲料利用最佳时的蛋白质水平分别大约是49%和46%,据此估算出暗纹东方鲀幼鱼的最适蛋白质含量为46%～49%,这一结果同红鳍东方鲀的最适蛋白质需要量基本一致.     

翘嘴红鲌对饲料蛋白的营养需求及豆粕对鱼粉的适宜替代量

选择健康的翘嘴红(Erythroculter ilishaeformisBleeker)为实验鱼,体质量(12.84±0.60)g。实验分为两部分进行。实验Ⅰ以褐鱼粉为蛋白源,配制5个蛋白水平(31.04%、35.51%、40.89%、46.62%、50.33%)的等能、等必需氨基酸(EAA)平衡关联度的半精制饲料,探讨翘嘴红对饲料蛋白的需求;经过8周饲养,实验Ⅰ的结果表明,饲料蛋白含量对翘嘴红的增重率、饲料效率和蛋白效率具有显著影响。方差分析表明,40.89%饲料蛋白组的鱼体增重率显著高于31.04%、35.51%饲料蛋白组(P<0.05),但是与46.62%和50.33%饲料蛋白组没有显著性差异(P>0.05);31.04%3、5.51%和40.89%饲料蛋白组的蛋白效率显著高于46.62%和50.33%饲料蛋白组(P<0.05);40.89%、46.62%和50.33%饲料蛋白组的饲料效率显著高于31.04%和35.51%饲料蛋白组(P<0.05)。依据折线模型分析翘嘴红的增重率、二次多项式回归分析蛋白质效率,适宜饲料蛋白水平为37.43%~41.15%。实验Ⅱ以豆粕替代鱼粉,大豆蛋白分别替代0.0%、13.5%、27%、40.5%和54%的鱼粉蛋白,配制5个EAA关联度的等蛋白(40%)、等能(20 MJ.kg-1)的半精制饲料,探讨翘嘴红饲料中大豆蛋白对鱼粉蛋白的适宜替代量。结果表明,当大豆蛋白分别替代13.5%2、7.0%和40.5%的鱼粉蛋白时,翘嘴红的增重率和蛋白效率与对照组差异不显著(P>0.05),而且都显著高于54.0%替代组(P<0.05),因此,本实验条件下,大豆蛋白对鱼粉蛋白的最大替代量为40.5%,饲料动、植物蛋白适宜比为3∶2。     

饲料不同蛋白水平对翘嘴鲌生长性能的影响

为了解翘嘴鲌对饲料中蛋白质的需求量,根据翘嘴鲌的体成分拟定饲料配方,设计了不同蛋白水平(蛋白质含量分别为34.46 %、37.20 %、38.82 %、41.5 %、43.58 %)的5种饲料,用以进行饲养试验,分别饲喂体质量相近(约1.2 g)的翘嘴鲌幼鱼。60 d后,测定每组幼鱼的生长性能(全长、体长、湿重、肌肉水分、粗蛋白及粗脂肪含量)。试验结果表明,翘嘴鲌的体长、全长、湿重随饲料蛋白水平的高低变化规律明显,蛋白水平为38.82 %的试验组,鱼的生长性能最佳。经回归分析得出的初步结论,并结合翘嘴鲌的生长和体蛋白积累情况,认为翘嘴鲌幼鱼饲料的适宜蛋白水平为39 %～40 %。     

饲料蛋白对翘嘴红鲌蛋白质周转代谢的影响

选择健康的翘嘴红(体重12.84±0.60g)为试验鱼,以红鱼粉为蛋白源,配制5个蛋白水平(31.04%、35.51%、40.89%4、6.62%、50.33%)的等能、等必需氨基酸(EAA)平衡关联度的半精制饲料;又以豆粕替代鱼粉,大豆蛋白分别替代0、13.5%、27%、40.5%、54%的鱼粉蛋白,配制5个EAA关联度的等蛋白(40%)、等能(20MJ.kg-1)的半精制饲料,探讨饲料蛋白水平和大豆蛋白对鱼粉蛋白的替代对翘嘴红肌肉和肝胰脏蛋白质周转代谢的影响。8周饲养结果表明,饲料蛋白水平对翘嘴红的特定增重率(SGR)具有显著性影响(P<0.05),40.89%饲料蛋白组的SGR显著高于31.04%、35.51%饲料蛋白组(P<0.05),但与46.62%和50.33%饲料蛋白组没有显著性差异(P>0.05);饲料蛋白水平对白肌、肝胰脏蛋白质生长率具有相似的影响,40.89%饲料蛋白组的白肌、肝胰脏蛋白质生长率分别达到2.13%.d-1,显著高于31.04%和35.51%两组(P<0.05),但与46.62%和50.33%饲料蛋白组无显著性差异(P>0.05)。饲料蛋白水平的增加促进了翘嘴红的生长和蛋白质的合成。肌肉蛋白质合成率(Ks)、蛋白质降解率(Kd)随饲料蛋白水平的增加而增加(P<0.05),肌肉蛋白质的增加归因于蛋白质合成的增加较降解的增加更占优势,蛋白质的沉积率在适宜蛋白水平时最高。当大豆蛋白分别替代13.5%2、7.0%4、0.5%的鱼粉蛋白时,翘嘴红的SGR与对照组差异不显著(P>0.05),而且都显著高于54.0%替代组(P<0.05)。白肌蛋白质生长率(Kg)也显著受到大豆蛋白替代的影响(P<0.01),当饲料中大豆蛋白对鱼粉蛋白替代量为40.5%时,与对照组相比,Kg极显著下降(P<0.01)。随着饲料中大豆蛋白对鱼粉蛋白替代量的增加,白肌Ks随之降低,当饲料中大豆蛋白对鱼粉蛋白替代量达54%时,与对照组相比,肌肉Ks显著下降(P<0.05)。白肌Kd与白肌Ks的变化趋势相似(P<0.1),而PDE没有受到饲料中大豆蛋白对鱼粉蛋白替代的影响(P>0.05)。可见随着大豆蛋白对鱼粉蛋白替代量的提高,氨基酸平衡关联度逐渐降低,蛋白质合成逐渐降低(P<0.05),生长下降,饲料必须氨基酸平衡程度的变化没有改变蛋白质的沉积效率。     

饲料蛋白水平对星斑川鲽幼鱼生长、体组成及血浆生化指标的影响

以鱼粉为蛋白源,配制5个不同蛋白质水平(34.85%,40.48%,46.54%,51.54%,56.69%)的等能饲料.以初始体质量为(54.52±0.23)g的星斑川鲽(Platichthys stellatus)为实验对象,在室内循环水养殖系统中进行54 d的摄食生长实验,研究饲料蛋白水平对星斑川鲽幼鱼生长、体组成及血浆生化指标的影响.结果显示:(1)增重率(WGR)和特定生长率(SGR)随着饲料蛋白水平的增加而上升,51.54%和56.69%饲料组之间差异不显著(P>0.05),其余各组差异显著(P<0.05);51.54%饲料组的蛋白质效率(PER)显著高于其他各组(P<0.05);51.54%饲料组的蛋白质沉积率(PRE)也显著高于34.85%、46.54%和56.69%组(P<0.05),但与40.48%饲料组差异不显著(P>0.05).以增重率为参考指标,折线回归分析结果表明,星斑川鲽幼鱼获得最佳增重时对饲料中蛋白质的需要量为53.56%.(2)饲料不同蛋白水平对星斑川鲽幼鱼鱼体灰分含量没有显著影响,但显著影响了鱼体粗蛋白、粗脂肪和水分的含量(P<0.05).51.54%饲料组鱼体粗蛋白含量最高,显著高于34.85%组(P<0.05),而与40.48%、46.54%和56.69%组之间无显著差异(P>0.05);鱼体粗脂肪含量随着饲料蛋白水平的升高而下降,水分含量表现出与粗脂肪含量相反的趋势.(3)饲料蛋白含量对星斑川鲽幼鱼部分血浆生化指标也产生了显著性的影响.血浆总蛋白(TP)以51.54%组最高,与56.69%组差异不显著(P>0.05),,但显著高于34.85%、40.48%和46.54%组(P<0.05);40.48%、51.54%和56.69%组间血浆尿素氮(BUN)含量差异不显著(P>0.05),但显著低于34.85%和46.54%组(P<0.05).综合以上结果,星斑川鲽饲料中蛋白质适宜添加量为51.54%～53.56%.     

饲料蛋白质和能量水平对草鱼生长和鱼体组成的影响

采用3×3因子试验确定不同蛋白质和脂肪水平饲料对草鱼生长和鱼体组成的影响。初始平均体质量为0.75g的试验鱼放养在27个规格为85cm×35cm×95cm的网箱中,每箱放养50尾。日粮中的蛋白源、脂肪源和可消化碳水化合物源,分别采用鱼粉、豆油和糊精配制,日粮设3个粗蛋白水平,每个蛋白水平有3个能量水平饲养草鱼84d。结果表明MPLL组(粗蛋白为30%,粗脂肪为4%)的特殊生长率和蛋白质效率最高,饲料系数最低,但与LPML组(粗蛋白为25%,粗脂肪为6%)差异不显著;总的来看,脂肪含量在4%和6%时特定生长率和饲料系数以中蛋白质组(MP,30%)最高,脂肪含量在8%时特定生长率和饲料系数以低蛋白质组(LP,25%)最高,表明饲料脂肪水平对鱼的生长和饲料系数有显著影响。随着饲料可消化能的增加,鱼体的脂肪含量增加,而蛋白和灰分含量没有多大变化。综合饲料成本等因素,本试验初步确定草鱼幼鱼生长所需的最适蛋白水平为25%,DP/DE约为23.47mg·kJ-1。     

饲料蛋白水平对鲈鱼生长、体组成及蛋白酶活力的影响

以初始体重为(34.15±0.33)g的鲈鱼Lateolabrax japonicus为研究对象,鱼粉和酪蛋白作为蛋白源,设计并制成蛋白质梯度分别为35%、40%、45%、50%、55%的5组配合饲料,进行为期56 d的生长试验,探讨配合饲料中不同蛋白质水平对鲈鱼生长、体组成及蛋白酶活力的影响。结果表明,各组鲈鱼存活率为91.7%-96.7%,无显著差异(P0.05);随着饲料蛋白质水平的提高,鲈鱼的特定生长率逐渐升高,当饲料蛋白质水平达到45%时趋于稳定,且饲料蛋白45%、50%、55%组试验的特定生长率显著高于35%组(P0.05);蛋白质沉积率呈先上升后下降的趋势,当饲料蛋白质水平达到45%时达到最大值;饲料蛋白质水平对鲈鱼鱼体水分含量无显著性影响(P0.05),鲈鱼鱼体粗蛋白含量随着饲料蛋白水平提高而增加,粗灰分、粗脂肪含量则呈减少趋势;随饲料蛋白质水平提高,胃蛋白酶和胰蛋白酶的活性呈升高趋势,肝脏组织中谷草转氨酶的活性呈现升高趋势,而谷丙转氨酶的活性没有显著性变化(P0.05)。饲料中蛋白水平为45.00%-45.89%,其生长及蛋白沉积率最高。     

Evaluation of optimum dietary protein-to-energy ratio in juvenile olive flounder Paralichthys olivaceus (Temminck et Schlegel)

An 8‐week feeding trial was conducted to estimate the optimum dietary protein to energy (P/E) ratio in juvenile olive flounder Paralichthys olivaceus. Eight experimental diets were formulated with two energy levels and four protein levels at each energy level. Two energy levels of 12.5 and 16.7 kJ g^?1 diets were included at crude protein (CP) levels of 25%, 30%, 35% and 45% with 12.5 kJ g^?1, and CP levels of 35%, 45%, 50% and 60% with 16.7 kJ g^?1. After 1 week of the conditioning period, fish initially averaging 8.1±0.08 g (mean±SD) were randomly distributed into the aquarium as groups of 15 fish. Each diet was fed on a dry‐matter basis to fish in three randomly selected aquariums at a rate of 3–5% of total wet body weight per day for 8 weeks. After 8 weeks of the feeding trial, weight gain (WG), feed efficiency ratio and specific growth rate of fish fed 45% CP with 16.7 kJ g^?1 energy diet were significantly higher than those from the other dietary treatments (P<0.05). WG of fish fed 12.5 kJ g^?1 energy diets increased with the increase of dietary protein levels. However, WG of fish fed 16.7 kJ g^?1 energy diets increased with the increase of dietary protein levels up to 45% CP and then decreased when fish fed 50% and 60% CP diets. Both dietary protein and energy affected protein retention efficiency and energy retention efficiency. Haemoglobin (Hb) of fish fed 35% and 45% CP diets with 12.5 kJ g^?1 energy were significantly high and not different from Hb of fish fed 45% and 50% CP diets with 16.7 kJ g^?1 energy. Haematocrit of fish fed 45% CP diet with 16.7 kJ g^?1 energy was significantly higher than those from fish fed 25% and 30% CP diets with 12.5 kJ g^?1 energy (P< 0.05). Based on the results of this experiment, we concluded that the optimum dietary P/E ratio was 27.5 mg protein kJ^?1 with diet containing 45% CP and 16.7 kJ g^?1 energy in juvenile olive flounder.     

Dietary arginine requirement of juvenile hybrid sturgeon (Acipenser schrenckii♀ × Acipenser baerii♂)

An 8‐week feeding trial was conducted to evaluate the dietary arginine requirement of juvenile hybrid sturgeon. Seven isonitrogenous and isolipidic diets were formulated to contain graded levels of dietary arginine ranging from 1.74% to 3.54% (dry weight). The results indicated that the fish fed with 1.76% arginine diet had lower specific growth rate (SGR) and feed efficiency ratio (FER) than the fish fed the 2.64% to 3.24% arginine diets (p < .05), and the fish fed the 2.64% arginine diet presented the highest SGR. The fish fed with 1.76% arginine diet had lower whole‐body crude protein content than the fish fed the 2.64% or 2.93% arginine diets (p < .05). Compared with the 1.76% arginine diet, 2.36% to 2.93% arginine diets significantly increased the total amino acid (TAA) concentration and total nonessential amino acid (TNEAA) of carcasses. The fish fed with 1.76% arginine diet had lower activity of nitric oxide synthase (T‐NOS) and content of nitric oxide (NO) than the fish fed the 2.05% to 2.93% arginine diets in the liver. The fish fed with 1.76%, 2.05% or 2.36% arginine diets had lower gene expression of growth hormone (GH) and insulin‐like growth factor I (IGF‐I) in the liver than the fish fed the 2.64% to 3.53% arginine diets in the liver (p < .05). A broken‐line analysis between SGR against the dietary arginine levels provided estimates for the optimal dietary arginine requirement of 2.47% corresponding to 6.18% of the dietary protein on a dry weight basis.     

Effect of dietary protein, lipid and carbohydrate ratio on growth, feed efficiency and body composition of pikeperch Sander lucioperca fingerlings

Pikeperch Sander lucioperca fingerlings were fed nine practical diets containing three levels of protein (P=34%, 43% and 50%), lipid (L=10%, 16% and 22%) and carbohydrate (C=10%, 15% and 20%) for 10 weeks in a recirculating water system at 23°C. Dietary treatments were distributed by orthogonal design with dietary energy content ranging from 15.5 to 23.1 MJ kg^?1 diet. Significant differences (P<0.05) in weight gain (%) and feed efficiency (FE) were observed after feeding trial. Relatively low growth and FE were found in fish fed diets containing 34% dietary protein level compared with that of fish fed diets with 43–50% protein levels, suggesting that 34% dietary protein probably is below the protein requirements of pikeperch fingerlings. Fish fed diets containing P43L10C15, P43L22C20 and P50L16C20 had significantly (P<0.05) higher weight gain and FE than fish fed the diets containing other dietary P/L/C ratios. There was no significant difference in weight gain and FE between fish fed diets of P43L10C15, P43L22C20 and P50L16C20. These results may indicate that pikeperch require at least 43% of dietary protein for adequate growth and FE, and considering the fish growth and feed ingredient cost P43L10C15 diet is more cost‐effective formulation for pikeperch fingerling. However, protein efficiency was not significantly affected by dietary P/L/C ratio.     

The effects of dietary protein and lipid on growth and body composition of juvenile and sub-adult red snapper, Lutjanus campechanus (Poey, 1860)

To allow for the initial identification of practical diet formulations for red snapper culture, the present study was conducted to evaluate the effects of feeding varying levels of dietary protein and lipid on growth and body composition of juvenile and sub‐adult red snapper. Twelve diets were formulated to contain varying levels of dietary protein and lipid. In trial 1, juvenile red snapper (initial mean weight 5.9 g) were offered diets with graded levels of dietary protein (32%, 36%, 40%, 44%) and practical energy to protein ratios. In trial 2, juvenile red snapper (initial mean weight 8.64 g) were offered isonitrogenous diets (44% protein) containing graded levels of dietary lipid (8%, 10%, 12%, 14%). Sub‐adult fish (initial mean weight 151.5 g) were used in trial 3 and maintained on diets similar to those of trial 1 (32–44% protein). Sub‐adult fish (initial mean weight 178.3 g) in trial 4 were offered isonitrogenous diets containing 32% dietary protein and graded levels of dietary lipid (6%, 8%, 10%, 12%). There were no significant differences in growth, feed efficiency ratio (FER) or survival in juvenile fish. Juvenile fish offered 32% dietary protein exhibited a significantly greater (P=0.0497) protein conversion efficiency (PCE) than fish offered a diet containing 44% dietary protein. Juvenile fish in trial 2 also had significantly higher (P=0.005) intraperitoneal fat ratios (IPFRs) at 14% dietary lipid than fish offered diets containing 8–10% dietary lipid, and displayed trends towards greater protein as a percent of whole‐body composition at 8–10% dietary lipid. Sub‐adult snapper in trials 3 and 4 showed no significant differences in growth, FER or survival. However, in trial 4 there was a general trend towards increased % weight gain (P=0.0615), FER (P=0.0601) and final mean weight (P=0.0596) with increasing levels of dietary lipid. Fish in trial 4 offered 6% dietary lipid also had significantly lower (P=0.0439) IPFR and PCE (P=0.0188) than fish offered 12% dietary lipid. Based on data obtained from these trials, inclusion of dietary protein at levels of 32–36% appears sufficient to support growth. For this level of protein, dietary lipid should be ～10% in order to meet the energetic demands of the fish and to spare dietary protein for growth.     

利用棉籽浓缩蛋白替代条纹锯(鮨)饲料鱼粉的潜力

通过10周生长实验评价了利用棉籽浓缩蛋白替代条纹锯鮨(Centropristis striata)饲料鱼粉的潜力。采用单因素实验设计,设4个鱼粉替代水平。对照饲料(C)中鱼粉含量为35%,通过添加棉籽浓缩蛋白分别替代饲料C中鱼粉的40%(R40)、60%(R60)和80%(R80)。每个处理设3个重复。实验鱼初始体重为29.5 ± 0.5g。实验期间,每天分两次按饱食量投喂实验饲料。结果表明：利用棉籽浓缩蛋白替代饲料鱼粉对鱼摄食、生长、饲料利用效率、鱼体组成和养殖废物(氮、磷和碳)排放量无显著影响,但单位鱼产量鱼粉消耗量(RCP)随饲料鱼粉含量下降而降低。基于生长、饲料成本、对环境的影响和RCP进行综合分析结果表明投喂饲料R80时养殖效益有别于投喂饲料C、R40和R60时。上述结果显示通过添加棉籽浓缩蛋白可将条纹锯鮨饲料鱼粉含量降低至7%。     

Effects of variable feed allowance with constant energy and ratio of energy to protein in a diet for constant protein input on the growth of common carp Cyprinus carpio L.

An 11‐week feeding trial was conducted to evaluate the effects of dietary protein and/or energy levels on growth, feed efficiency and proximate composition of juvenile (average weight: 21.5 g) common carp (Cyprinus carpio L.) fed various diets based on constant daily protein input. Five experimental diets were prepared. One group of diets (diets 1, 2 and 3) contained three crude protein (P) levels (35%, 40% and 45%) with a constant gross energy (GE) of 3.8 kcal g^?1 diet. The second group of diets (diets 4 and 5) were formulated to contain a GE of 4.3 or 4.9 kcal g^?1 diet and 40% or 45% protein levels, respectively, where GE/P was constant at 10.8 kcal g^?1 protein. Fish receiving diet 1 served as the control; they were hand‐fed to visual satiety. Feed allowance for diets 2 and 4 was 87.5% of the control. Feed allowance for fish receiving diets 3 and 5 was 77.8% of the control. Thus, all tanks received the same daily protein input. When gross energy in the diets was constant, 3.8 kcal g^?1 diet, weight gain of fish fed diet 2 at 87.5% satiation was significantly higher than that of fish fed diet 3 at 77.8% of satiation. When the GE/P in the diets was constant, 10.8 kcal g^?1 protein, weight gain of fish fed diet 1 was significantly higher than that of fish fed diet 5 at 77.8% satiation. The feed efficiency ratio (FER) for diets 2–5 was significantly higher than for diet 1 at constant GE and GE/P, and this improved linearly as dietary protein levels increased. The protein efficiency ratio (PER) for diet 2 was significantly higher than for diet 3 at constant GE. However, PER was not significantly different at constant GE/P. Protein retention of fish fed diet 2 was significantly higher than that of fish fed diet 3 at constant GE. Protein retention of fish linearly decreased at constant GE/P. The energy efficiency ratios (EER) for diets 2 and 3 were significantly higher than for diet 1 at constant GE. Moisture and protein contents of the whole body of fish were not significantly different at constant GE, but they decreased linearly at constant GE/P. The lipid content of fish fed diet 1 was significantly lower than that of fish fed diet 2 at constant GE, and body lipid content linearly increased at constant GE/P. These results indicate that growth and feed efficiency for common carp fed a 40% protein diet with 3.8 kcal g^?1 diet GE at 87.5% satiation rate was superior to those for the fish fed either a 35% protein diet with 3.8 kcal g^?1 diet GE at 100% satiation rate or a 45% protein diet with either a 3.8 or 4.9 kcal g^?1 diet GE at 77.8% satiation rate.     

酸制剂对罗非鱼生长和饲料利用的影响

为考察不同酸制剂对奥尼罗非鱼幼鱼生长和饲料利用的影响,在基础饲料(对照组)中分别添加0.3%磷酸、富马酸、柠檬酸和乳酸,饲养奥尼罗非鱼幼鱼9周(初始平均体重约1.9g)。结果表明,添加0.3%柠檬酸和乳酸饲料组的罗非鱼特定生长率显著高于对照组和添加富马酸组(P<0.05);磷酸组、柠檬酸组和乳酸组的饲料效率较对照组有提高趋势(P>0.05),乳酸组的饲料效率显著高于富马酸组(P<0.05);柠檬酸组和乳酸组鱼体水分含量显著高于富马酸组(P<0.05),体粗蛋白、粗脂肪和灰分含量在组间差异不显著(P>0.05);胃蛋白酶活性在富马酸组显著低于其它饲料组(P<0.05),肠淀粉酶活性在柠檬酸组和乳酸组显著高于对照组(P<0.05);肝脏代谢酶活性在柠檬酸组和乳酸组显著高于对照组、磷酸组和富马酸组(P<0.05),相应地,柠檬酸组和乳酸组罗非鱼血清甘油三酯含量显著高于对照组(P<0.05)。结果说明,添加0.3%柠檬酸和乳酸能显著促进罗非鱼幼鱼生长,提高饲料的利用,富马酸降低罗非鱼对饲料的利用。     

Growth and efficiency of feed usage by Atlantic salmon (Salmo salar) fed diets with different dietary protein: Energy ratios at two feeding levels

The effect of dietary digestible protein/digestible energy (DP/DE) ratios and feeding level on growth, feed efficiency, nutrient and energy usage by Atlantic salmon ( Salmo salar ; initial body weight, 7.0 g/fish) at 15°C was investigated in a 16-week feeding trial. Three diets, differing in their DP and DE contents, namely 37/18 (regular diet, RD), 37/21 (high fat diet, HF) and 44/ 22 (high nutrient-dense diet, HND) g/MJ of dry feed were formulated. DP/DE ratios were 20, 18 and 20 g/MJ for the RD, HF and HND diets, respectively. Salmon were hand-fed three times a day at either 100% or 85% of the feed requirement estimated by a bioenergetics model. At each feeding level, DE intake (kJ/fish) was similar for all three diets. Diet composition did not affect growth rate. However, increasing the digestible energy density from 18 to 22 MJ/kg of dry feed resulted in a significant increase ( P  < 0.05) in feed efficiency. Restricting feed intake significantly decreased live body weight gains for all diets. However, feed efficiency was not affected by feeding level. Diet composition and feeding level did not affect carcass composition and nutrient and energy usage, with the exception of a higher ( P  < 0.05) carcass lipid of fish fed the HF100 diet compared with the fish fed the RD and HND diets and a higher ( P  < 0.05) lipid gain (g/fish) of fish fed the HF100 diet compared with fish fed all the diets at the restricted feeding level. Restricting feeding resulted in significantly lower ( P  < 0.05) energy gain (kJ/fish) compared with fish fed at 100%. Increasing the DE and nutrient density of the diet had no effect on growth but improved feed efficiency and lowered solid wastes (g of solid wastes per kg of fish produced) while dissolved wastes were not affected by dietary ormulation.     

Optimum dietary protein level for maximum growth of juvenile olive flounder Paralichthys olivaceus (Temminck et Schlegel)

This experiment was conducted to determine the optimum dietary protein level for juvenile olive flounder Paralichthys olivaceus (Temminck et Schlegel) fed a white fish meal and casein‐based diets for 8 weeks. Olive flounder with an initial body weight of 4.1 ± 0.02 g (mean ± SD) were fed one of the six isocaloric diets containing 35%, 45%, 50%, 55% and 65% crude protein (CP) at a feeding rate of 4–5% of wet body weight on a dry‐matter basis to triplicate groups of 20 fish per aquarium. After 8 weeks of feeding, per cent weight gain (WG) and feed efficiency ratios of fish fed the 55% CP diet were not significantly higher than those from fish fed the 50% and 65% CP diets, but significantly higher than those from fish fed the 35% and 45% CP diets. Fish fed the 50%, 55% and 65% CP diets had significant higher specific growth rates than did fish fed the 35% and 45% CP diets; however, there was no significant difference among fish fed the 50%, 55% and 65% CP diets. The protein efficiency ratio was inversely related to the dietary protein level; that is, maximum efficiency occurred at the lowest dietary protein level. Broken‐line model analysis indicated that the optimum dietary protein level was 51.2 ± 1.8% for maximum weight gain in juvenile olive flounder. The second‐order polynomial regression analysis showed that the maximum WG occurred at 57.7% and it revealed that the minimum range of protein requirement was between 44.2% and 46.4%. These findings suggest that the optimum dietary protein level for maximum growth could be greater than 46.4%, but less than 51.2% CP in fish meal and casein‐based diets containing 17.0 kJ g^?1 energy for juvenile olive flounder.     

饲料蛋白质和能量水平对红姑鱼生长和鱼体组成的影响

采用 3× 3因子试验确定不同蛋白质和脂肪水平实用饲料对红姑鱼生长和鱼体组成的影响。初始平均体重为 2 .73g的试验鱼放养在 2 7个 2 .5m× 1.5m× 1.3m的网箱中 ,每箱放养 6 0尾。用饲料蛋白质水平为38% ,42 %和 46 % ,脂肪水平为 5 % ,8%和 12 %的试验饲料饲养鱼 8周。结果表明特定生长率和饲料系数以高蛋白质组 (HP ,46 % )显著高于中蛋白组 (MP ,42 % )和低蛋白组 (LP ,38% ) (P <0 .0 5 ) ;饲料脂肪水平对鱼的生长和饲料系数没有显著影响 (P >0 .0 5 ) ;随饲料DP/DE降低 ,脏体比和肝体比增加 ;随饲料可消化能增加 ,全鱼和肝脏的脂肪含量增加 ,但对机体的蛋白含量、氨基酸构成和灰分含量没有多大的影响。从本试验可初步认为红姑鱼幼鱼最适饲料蛋白质水平为 46 % ,可消化蛋能比 (DP/DE)为 119mg·kcal-1。