饲料中碳水化合物水平对鲈鱼生长、生理状态参数及体组成的影响

以初始体重(34.26±0.37)g的鲈鱼Lateolabrax japonicus为研究对象,进行为期70d的生长实验,探讨饲料中不同的碳水化合物(CHO)水平对其生长、饲料利用、血糖水平和糖酵解酶活力的影响。实验配制6种不同CHO水平(0、6%、12%、18%、24%和30%)的等氮等脂饲料。结果表明,随着饲料中CHO水平的升高,特定生长率(SGR)和饲料效率(FE)均呈现先上升后下降的趋势,都在12%组达到最大值,并显著高于24%和30%组(P0.05),而肝体比(HSI)和脏体比(VSI)呈显著升高的趋势(P0.05),且在30%组达到最大值。饲料中不同CHO水平对鲈鱼成活率、肥满度、肌糖原和己糖激酶(HK)活力均无显著影响(P0.05)。饲料中不同CHO水平显著提高了鲈鱼粗蛋白和粗脂肪含量(P0.05),降低了灰分含量(P0.05)。饲料干物质的表观消化率(ADC)在各组之间差异显著(P0.05),18%组显著高于其余5组(P0.05),12%组饲料蛋白质的ADC显著高于对照组(P0.05)。血清中葡萄糖、甘油三酯、胆固醇含量随着饲料中CHO水平的增加而逐渐上升(P0.05),肝糖原含量先显著升高后趋于平稳(P0.05)。以SGR为评价指标,用二次曲线模型分析得出鲈鱼饲料中CHO的适宜添加量为17.75%。     

鲈幼鱼对饲料中苏氨酸的需要量

以初始体质量(8.00±0.20)g的鲈为实验对象,在海水网箱(1.5 m×1.5 m×2.0 m)中进行为期8周的摄食生长实验,研究鲈对饲料中苏氨酸的需要量。通过在半精制基础饲料中添加晶体L-苏氨酸使饲料中苏氨酸含量分别达到0.75%、1.03%、1.36%、1.67%、2.04%和2.31%,配制成6水平等氮等能饲料(41.83%粗蛋白质,19.68 kJ/g总能)。每种饲料设3个重复,每个重复随机放养30尾鲈。实验采用表观饱食投喂方式,每天投喂2次(06:00和17:30),实验期间水温为26～32℃,盐度为22～28,溶解氧含量在7 mg/L左右。实验结果表明,各饲料处理组成活率(94.4%～98.9%)无显著差异。随着饲料中苏氨酸含量的增加,鲈的增重率显著升高(150.3%～256.9%)(P<0.05),且在1.67%苏氨酸饲料组达到最大值(256.9%),然而,随着饲料中苏氨酸含量的进一步增加,增重率有下降的趋势。鲈的氮累积率随着饲料中苏氨酸含量的增加而显著升高(13.18%～26.36%)(P<0.05),且在1.67%苏氨酸饲料组达到最大值(26.36%),随着饲料中苏氨酸含量的进一步增加,氮累积率有下降的趋势。饲料苏氨酸含量对鲈鱼体粗蛋白、粗脂肪和灰分含量无显著影响。以增重率和氮累积率为评价指标经二次回归分析得出,鲈对饲料中苏氨酸的需要量分别为1.77%和1.88%,占饲料蛋白质的4.21%和4.47%。     

Effects of six alternative lipid sources on growth and tissue fatty acid composition in Japanese sea bass (Lateolabrax japonicus)

Ten-week experiment was carried out on Japanese sea bass (5.87 ± 0.02 g) to study the effects of replacement of fish oil with six alternative lipid sources: pork lard, PL; beef tallow, BT; poultry fat, PF; soybean oil, SO; corn oil, CO; and a mixed-fat (MF: tallow, 60%; soy oil, 20%; fish oil, 20%) on growth performance and fatty acid (FA) composition in fillet and liver. Seven isoenergetic and isonitrogenous experimental diets were formulated, containing 10% of added lipid. Fish oil was used in control diet, which was substituted by 50% with the alternative lipid sources in the other six diets.

Weight gain (WG), specific growth rate (SGR), Feed conversion ratio (FCR) feed intake and hepatosomatic index (HSI) of fish fed the experimental diets were not significantly different (P > 0.05). Protein efficiency ratio (PER) in fish fed the PF diet were significantly lower than those of fish fed SO and CO diets. Significant differences in carcass moisture and lipid contents of carcass and liver were observed among fish fed the dietary treatments. Generally, the fatty acid composition of fish fillets and livers reflected the dietary FA composition.     

Estimation of dietary biotin requirement of Japanese seabass,Lateolabrax japonicus C.

A 9‐week feeding experiment was conducted to determine the dietary biotin requirement of Japanese seabass, Lateolabrax japonicus C. Six isonitrogenous and isoenergetic purified diets (Diets 1–6) containing 0, 0.01, 0.049, 0.247, 1.238 and 6.222 mg biotin kg^?1 diet were fed twice daily to triplicate groups (30 fish per group) of fish (initial average weight 2.26 ± 0.03 g) in 18 fibreglass tanks (300 L) filled with 250 L of water in a flow‐through system. Water flow rate through each tank was 2 L min^?1. Water temperature ranged from 25.0 to 28.0 °C, salinity from 28.0 to 29.5 g L^?1, pH from 8.0 to 8.1 and dissolved oxygen content was approximately 7 mg L^?1 during the experiment. After the feeding experiment, fish fed Diet 1 developed severe biotin deficiency syndromes characterized by anorexia, poor growth, dark skin colour, atrophy and high mortality. Significant lower survival (73.3%) was observed in the treatment of deficient biotin. The final weight and weight gain of fish significantly increased with increasing dietary biotin up to 0.049 mg kg^?1 diet (P < 0.05), and then slightly decreased. Both feed efficiency ratio and protein efficiency ratio showed a very similar change pattern to that of weight gain. Dietary treatments did not significantly affect carcass crude protein, crude lipid, moisture and ash content. However, liver biotin concentration (0–6.1 μg g^?1) significantly increased with the supplementation of dietary biotin (P < 0.05), and no tissue saturation was found within the supplementation scope of biotin. Broken‐line regression analysis of weight gain showed that juvenile Japanese seabass require a minimum of 0.046 mg kg^?1 biotin for maximal growth.     

Effects of dietary squid viscera meal on growth and cadmium accumulation in tissues of Japanese seabass, Lateolabrax japonicus (Cuvier 1828)

Cadmium (Cd) is a toxic environmental pollutant with a long biological half‐life and can produce both hepatic and renal injuries in mammals and fish. Squid viscera meal (SVM), an effective attractant for aquatic animals, is widely used as an ingredient in aquafeeds. However, SVM is rich in Cd and its complexes. A study was conducted to evaluate the effects of dietary SVM on the growth and Cd deposition in tissues of Japanese seabass, Lateolabrax japonicus. Three practical diets were formulated to contain 0, 50 and 100 g SVM kg^?1 diet, respectively, containing 0.21, 7.26 and 12.08 mg Cd kg^?1 diet. Each diet was randomly assigned to triplicate groups of 80 Japanese seabass (mean initial weight, 10.89±0.21 g) in floating sea cages (1.5 × 1.5 × 2.0 m). Fish were fed twice daily (06:30 and 16:30 hours) to satiation for 8 weeks. The results showed that there were no significant differences in fish survival among three dietary treatments, but significant higher specific growth rates (SGR) were observed in the fish fed diets with 50 or 100 g SVM kg^?1 diet than that from the control group (P<0.05). The Cd concentrations in the kidney, liver and gill were found in a decreasing order at each treatment, and positively correlated with dietary Cd levels. Fish fed diets with 50 and 100 g SVM kg^?1 diet had significantly higher Cd accumulations in the kidney (3.25, 5.85 mg kg^?1), liver (0.76, 1.26 mg kg^?1) and gill (0.42, 0.58 mg kg^?1) compared with the control group (0.82, 0.34 and 0.32 mg kg^?1 respectively) (P<0.05). The Cd concentration in fish muscle; however, was undetectable in any treatment. Therefore, based on these results, accumulation of Cd in edible tissue (muscle) of farmed Japanese seabass is not a food safety issue. However, long‐term feeding of diets with SVM may result in accumulation of Cd in the kidneys, liver and gills of fish.     

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。     

饥饿及恢复投饵过程中花鲈肌肉组成及非特异免疫水平的变化

探讨了饥饿及恢复投饵过程中花鲈（Lateolabrax japonicus）（196±38g）肌肉组成分及鱼体非特异免疫水平的变化。实验设S0组（对照组,持续正常投喂）,S5组（饥饿5d后恢复正常投喂）,S10组（饥饿10d后恢复正常投喂）,S15组（饥饿15d后恢复正常投喂）。S0组每隔5d取样,S5,S10和S15组分别在结束饥饿及恢复投饵后每隔5d取样测定。结果显示：饥饿程度对花鲈肌肉组成有显著影响。与对照组相比,S10组饥饿结束时肌肉的总脂含量显著降低;S15组饥饿结束时肌肉的总脂含量和粗蛋白含量都显著降,同时显著增加了肌肉的水分含量。表明饥饿过程中花鲈先动用肌肉脂肪,后动用肌肉蛋白。在恢复投饵过程中,S10和S15组总脂含量表现出先降后升的规律,而S15组蛋白表现为逐步回升的趋势。表明花鲈在饥饿后恢复投饵的过程中,先恢复肌肉蛋白含量,后恢复肌肉脂肪含量。饥饿15d时花鲈血清蛋白浓度显著降低。与对照组相比,S5组血清、脾脏和头肾溶菌酶活性均无显著变化;S10组头肾溶菌酶活性在恢复投饵10d时补偿性升高。S15组在饥饿结束时显著降低了花鲈头肾溶菌酶活性,但在恢复投饵5d时恢复到对照组水平。花鲈白细胞的吞噬活性也受饥饿程度及恢复投饵的影响。饥饿会降低花鲈血液白细胞的吞噬活性。在恢复投饵过程中,饥饿（5d）后恢复投饵会引起白细胞吞噬百分率和吞噬指数的补偿性升高。表明饥饿及恢复投饵也影响花鲈的非特异免疫水平。     

Effects of dietary ethoxyquin on growth,feed utilization and residue in the muscle of juvenile Japanese seabass,Lateolabrax japonicus

Ethoxyquin (EQ) is the most common synthetic antioxidant used for preventing rancidity in fish foodstuffs. However, literature related to the effects of dietary EQ on performance of fish was limited. The present study was conducted to investigate the effects of EQ on performance and EQ residue in muscle of juvenile Japanese seabass Lateolabrax japonicus and to estimate the optimal EQ concentration in the diet. Graded levels [0 (control), 50, 150, 450 and 1350 mg EQ kg^?1 diet] of EQ were added to the basal diet, resulting in five dietary treatments in the experiment. Each diet was fed to triplicate groups of seabass (initial body weight 8.01 ± 0.76 g) for 12 weeks in floating sea cages (1.5 × 1.5 × 2.0 m, 30 fish per cage). Survival ranged from 78.9 to 86.7%, and was irrespective of dietary EQ levels. The specific growth rate (SGR) of fish fed diets supplemented with ≤50 mg kg^?1 EQ had significantly (P < 0.05) higher SGR than fish fed diets supplemented with ≥150 mg kg^?1 EQ, the highest SGR was observed in fish fed diet with 50 mg kg^?1 EQ supplementation. Feed intake (FI) and feed efficiency (FE) were not significantly (P > 0.05) different among dietary treatments. Fish fed diets with 50 and 1350 mg kg^?1 EQ had a significant (P < 0.05) lower body lipid content than fish in the control group. Muscle EQ level significantly increased when dietary EQ increased. Optimal EQ concentration estimated by polynomial regression based on maximum growth of juvenile Japanese seabass was 13.78 mg kg^?1 diet.     

Effects of dietary protein to energy ratios on growth and body composition of juvenile Chinese sucker,Myxocyprinus asiaticus

A growth experiment was conducted to investigate effect of dietary protein to energy ratios on growth and body composition of juvenile Myxocyprinus asiaticus (initial mean weight: 10.04 ± 0.53 g, mean ± SD). Nine practical diets were formulated to contain three protein levels (340, 390 and 440 g kg^?1), each with three lipid levels (60, 100 and 140 g kg^?1), in order to produce a range of P/E ratios (from 22.4 to 32.8 mg protein kJ^?1). Each diet was randomly assigned to triplicate groups of 20 fish in 400‐L indoors flow‐through circular fibre glass tanks provided with sand‐filtered aerated freshwater. The results showed that the growth was significantly affected by dietary P/E ratio (P < 0.05). Fish fed the diets with 440 g kg^?1 protein (100 and 140 g kg^?1 lipid, P/E ratio of 31.43 and 29.22 mg protein kJ^?1) had the highest specific growth rates (SGR) (2.16 and 2.27% day^?1, respectively). However, fish fed the diet with 390 g kg^?1 protein and 140 g kg^?1 lipid showed comparable growth (2.01% day^?1), and had higher protein efficiency ratio (PER), protein productive value (PPV) and energy retention (ER) than other groups (P < 0.05). No significant differences in survival were found among dietary treatments. Carcass lipid content was positively correlated with dietary lipid level, but irrespective of protein level and inversely correlated with carcass moisture content. Carcass protein contents increased with increasing dietary lipid at each protein level. The white muscle and liver composition showed that lipid increased with increasing dietary lipid level (P < 0.05). Dietary protein concentrations had significant effect on condition factor (CF), hepatosomatic index (HSI) and viscerosomatic index (VSI) (P < 0.05). However, dietary lipid concentrations had no significant effect on CF, HSI (P > 0.05). Based on these observations, 440 g kg^?1 protein with lipid from 100 to 140 g kg^?1 (P/E ratio of 29.22 to 31.43 mg protein kJ^?1) seemed to meet minimum requirement for optimal growth and feed utilization, and lipid could cause protein‐sparing effect in diets for juvenile Chinese sucker.     

饲料蛋白能量比对红鳍东方鲀幼鱼的生长性能、饲料利用和体组成的影响

为探求红鳍东方鲀(Takifugu rubripes)幼鱼饲料的最适蛋白质能量比,以鱼粉和豆粕作为主要蛋白源,鱼油和豆油作为主要脂肪源,配制粗蛋白含量分别为36％、42％和48％,粗脂肪含量分别为8％、12％和16％,蛋能比为17.06～24.20 mg/kJ的9组饲料.投喂初始体重为14.95 g的红鳍东方鲀幼鱼56...     

饲料中硒的添加水平对鲈鱼生长性能及相关酶活性的影响

在基础饲料中分别添加硒至0.0 mg.kg-1、0.2 mg.kg-1、0.4 mg.kg-1、0.6 mg.kg-1、0.8 mg.kg-1和1.0 mg.kg-1,分别饲喂鲈鱼(Lateolabrax japonicus)10周,观察其对鲈鱼生长性能、肝脏及血液中谷胱甘肽过氧化物酶(GSH-Px)、肝脏谷胱甘肽还原酶(GR)、肝脏谷胱甘肽转移酶(GST)活性的影响。实验鲈鱼初始体质量为(26.5±1.02)g,实验结束后饥饿24 h再进行测定。结果显示,SGR的最大值及FCR的最小值均出现在硒水平0.4 mg.kg-1饲料组,该组鱼体蛋白质含量也显著高于其他各组(P<0.05);硒水平为0~0.4 mg.kg-1饲料组鲈鱼的肝脏、血清中GSH-Px活性随着硒添加量的增加而提高,饲料硒水平为0.4 mg.kg-1时达到最高,当硒的添加水平继续提高到0.8~1.0 mg.kg-1时,鲈鱼的肝脏、血清中GSH-Px活性均显著下降(P<0.05);肝组织GR活性在饲料硒水平达到0.4 mg.kg-1时达到最高值,饲料硒水平为0.6 mg.kg-1时,GR的活性显著下降(P<0.05)。建议鲈鱼饲料硒的适宜添加水平为0.4 mg.kg-1     

添加晶体或包膜DL-蛋氨酸对利用豆粕替代花鲈饲料中鱼粉的影响

通过8周生长实验检验了添加晶体或包膜DL-蛋氨酸对利用豆粕替代花鲈饲料中鱼粉的影响,以确定添加DL-蛋氨酸对提高饲料鱼粉替代水平的作用。对照饲料鱼粉水平为40%。采用2×4实验设计,按等蛋白替代原则分别用豆粕替代对照组饲料中鱼粉的40%（L）和80%（H）;在每个鱼粉替代水平上,分别添加晶体DL-蛋氨酸（A）、包膜DL-蛋氨酸（B）、晶体DL-蛋氨酸和包膜材料（C）以及按1:1比例配制的B和C的混合物（D）。配成8种等氮、等脂肪的实验饲料（LA、LB、LC、LD、HA、HB、HC和HD）。饲料LA、LB、LC和LD含24%鱼粉,并分别添加0.5% A、1.3%B、1.3%C或1.3%D;饲料HA、HB、HC和HD含8%鱼粉,并分别添加0.7% A、1.8% B、1.8% C或1.8% D。实验鱼初始体质量为（6.0 ± 0.1）g。实验结果表明,饲料鱼粉替代水平显著影响花鲈增重（WG）、摄食率（FI）、饲料系数（FCR）、饲料氮沉积效率（NRE）、饲料氮废物排放量（TNW）、肝体比（HSI）以及全鱼水分和粗脂肪含量;DL-蛋氨酸剂型可显著影响饲料磷废物排放量（TPW）。当添加的DL-蛋氨酸剂型相同时,WG和NRE随饲料鱼粉替代水平增加而下降,而FCR和TNW增加;在相同饲料鱼粉替代水平下,添加晶体或包膜DL-蛋氨酸未导致花鲈WG、FCR、NRE、CF、HSI、鱼体组成、TNW和TPW出现显著差异。上述结果显示,通过添加豆粕可将花鲈饲料中鱼粉含量降低至24%,而添加晶体或包膜DL-蛋氨酸不能进一步提高利用豆粕替代饲料鱼粉的水平。     

Influence of different dietary amino acid patterns on growth and body composition of juvenile Japanese flounder, Paralichthys olivaceus

A feeding trial using five semi-purified diets (50% crude protein) was conducted to investigate the effects of different dietary amino acid patterns on growth and body composition of juvenile Japanese flounder. The control diet contained casein and gelatin as intact protein sources and four other diets contained 30% casein–gelatin (2:1, w/w) and 20% crystalline amino acids (CAA). CAA were added to the diets to simulate the amino acid pattern found in red sea bream egg protein (REP), Japanese flounder larvae whole body protein (FLP), Japanese flounder juvenile whole body protein (FJP), and brown fish meal protein (BFP), respectively. The test diets were fed to triplicate groups of juveniles (2.75±0.05 g) twice a day for 40 days to evaluate weight gain, survival, feed conversion efficiency (FCE), protein efficiency ratio (PER), and apparent protein utilization (APU). The apparent retention of total dietary amino acids in the whole body and A/E ratios of the whole body were also evaluated. The highest weight gain was observed in fish fed the diet containing the dietary amino acid pattern of BFP followed by fish fed the control, FJP, FLP and the REP diets. Percent survival, FCE, PER and APU were also significantly (P<0.05) affected by the amino acid pattern in the diets, indicating the highest value in fish fed the BFP diet. Except for a few amino acids, the amino acid composition of the whole body did not show marked differences with different dietary amino acid pattern. Results suggest that BFP could be more suitable as a reference amino acid pattern in the diet of juvenile Japanese flounder compared to the amino acid pattern of FLP, FJP or REP.     

Effects of dietary cholesterol on growth, survival and body composition of juvenile abalone Haliotis discus hannai Ino

An experiment was conducted to determine the dietary cholesterol requirement of juvenile abalone Haliotis discus hannai. Eight isoenergetic (18.15–18.61 kJ/g) and isonitrogenous (29.00–29.78% protein) diets, supplemented with 0.00, 0.15, 0.30, 0.45, 0.60, 0.75, 0.90 and 1.05% cholesterol were evaluated. Juvenile abalone (initial weight: 0.67–0.72 g) were reared in a flow-through water system for 24 weeks. During the feeding trial, water temperature was maintained at 14–17 °C, salinity 31–33, pH 7.4–7.9. Abalone fed diet without cholesterol supplementation had the lowest weight gain ratio (WGR, 356.70%). Survival ranged from 98.52 to 100.00% and was not significantly different among treatments. There were no significant effects of dietary cholesterol on composition and cholesterol concentration in the muscle and viscera of abalone. Based on data of WGR using broken-line analysis, the optimal dietary cholesterol requirement of juvenile abalone was found to be 0.23%.     

不同蛋白水解物对花鲈(Lateolabrax japonicus)生长性能及非特异性免疫的影响

实验以基础饲料组[含30％鱼粉蛋白(FM)]为对照组,用鱼蛋白水解物(FPH)、猪血蛋白水解物(PBPH)、酵母蛋白水解物(YPH)和豆粕蛋白水解物(SPH)分别替代配方中10％的鱼粉蛋白,配制成5组等氮等脂的饲料,喂养初始平均体重为31.99 g的花鲈(Lateolabrax japonicus)8周,探讨饲料中不同蛋白水解物对花鲈生长、饲料利用、体组成成分及非特异性免疫的影响.结果显示:各处理组实验鱼存活率在97.78％-98.89％之间,没有显著性差异(P＞0.05);FPH组与FM组的末重和特定生长率最高,两者之间没有显著差异(P＞0.05),但显著高于PBPH组、SPH组和YPH组(P＜0.05);FPH组饲料效率高于FM组、PBPH组和YPH组(P＞0.05),且显著高于SPH组(P＜0.05);各实验处理组鲈鱼摄食率没有显著差异(P＞0.05);FPH组蛋白效率比显著高于FM组、PBPH组、SPH组和YPH组(P＜0.05);FPH组、FM组和YPH组的蛋白质沉积率显著高于PBPH组和SPH组(P＜0.05).饲料中添加FPH和YPH会显著增加花鲈肝脏和血清中碱性磷酸酶、酸性磷酸酶、超氧化物歧化酶、溶菌酶活性和总抗氧化能力,显著高于FM组、PBPH组和SPH组(P＜0.05).FPH组的花鲈鱼体粗蛋白含量高于FM组和YPH组,但差异不显著(P＞0.05),FPH组显著高于PBPH组和SPH组(P＜0.05).综上所述,4种不同蛋白水解物替代鱼粉后投喂花鲈幼鱼,鱼蛋白水解物效果最好,其次是酵母蛋白水解物、猪血蛋白水解物和豆粕蛋白水解物.     

Effect of dietary taurine levels on growth and feeding behavior of juvenile Japanese flounder Paralichthys olivaceus

This study was conducted to investigate the effect of dietary taurine levels on growth and feeding behavior of juvenile Japanese flounder. Three different taurine level diets were prepared by supplementation of taurine (T-0%, 0.5% and 1.5%) to the basal diet. Fish meal washed with 70% ethanol to remove taurine was used as the sole protein source. Feeding experiments were carried out twice at 20 °C by using different size of fish (average body weight: 0.3 g in Experiment I and 3.7 g in Experiment II). The feeding behavior of fish was observed throughout the experimental period. At the end of experiments, fish were killed for amino acids analysis.

The final average body weight and feed efficiency of juvenile Japanese flounder fed the T-1.5% diet was significantly higher than those of fish fed the T-0% diet in Experiments I and II. Abnormal feeding behavior such as multiple feeding while swimming in the water column was observed in the T-0% group in Experiment I. These findings indicate that taurine is essential for normal growth and development of normal feeding behavior of juvenile Japanese flounder.     

饵料蛋白能量比对黑鲷幼鱼生长和体成分的影响

取黑鲷(Sparusmacrocephalus)幼鱼960尾,体重(3.39±0.18)g,以鱼粉和豆粕作为蛋白源,鱼油和豆油等比例混合油作为脂肪源,共配制4个蛋白水平(34%、38%、42%、46%),每一蛋白水平设3个脂肪水平(10%、13%、16%),共12种饵料,糖水平保持在16%左右,饵料的蛋白能量比(P/E)在96.76～136.21mg/kcal。黑鲷幼鱼随机分成12组,每组设2重复,实验为期42d。结果表明,对特定生长率(SGR)与饵料系数(FCR)的影响,以较高蛋白组(38%、42%、46%)显著优于低蛋白组(34%)(P<0.05),中、高脂肪组(13%、16%)显著优于低脂肪组(10%)(P<0.05);各组饵料对成活率的影响无显著差异(P>0.05)。当蛋白水平为42%,脂肪水平为16%时,黑鲷幼鱼获得最大特定生长率(3.20)、最高蛋白质效率(2.10)和最小饵料系数(1.14)。全鱼脂肪含量随着饵料中脂肪水平的提高而逐渐升高。在同一饵料蛋白水平内,全鱼蛋白与灰分含量随着饵料脂肪水平的提高呈逐渐升高趋势。经统计分析,饵料中不同蛋白能量比显著影响黑鲷幼鱼生长(P<0.05),饵料中脂肪有明显节约蛋白质的作用(P<0.05)。由生长及体成分的实验结果得出,黑鲷幼鱼的最适饵料蛋白水平为42%,最适蛋白能量比(P/E)为110.37mg/kcal。     

海水养殖花鲈对几种饲料蛋白原料的表观消化率

测定了在室内海水流水系统中养殖的花鲈对7种常用饲料原料,宠物级鸡肉粉(P-PBM)、饲料级鸡肉粉(F-PBM)、血粉(BM)、羽毛粉(FEM)、蚕蛹粉(SWP)、豆粕(SBM)和菜粕(RSM)以及1种混合动物蛋白粉(MM=50%P-PBM+20%F-PBM+20%BM+10%FEM)的干物质、蛋白质和能量表观消化率(ADC)。实验饲料由70%基础饲料(蛋白质含量为42.0%,能量含量为18.9MJ/kg)和30%的待测原料组成。基础饲料和实验饲料中均添加1%(质量分数)的Cr2O3作为外源标记物。饲养实验共进行4周。实验期间每天投饵两次,采用虹吸方法收集粪便。实验结果显示:花鲈对P-PBM、F-PBM、BM、FEM、MM、SWP、SBM和RSM干物质ADC分别为61%～87%,蛋白质ADC为80%～96%,能量ADC为75%～93%。其中,花鲈对SBM的蛋白质ADC最高,对MM的蛋白质ADC最低,对BM的干物质和能量ADC最高,对RSM的干物质和能量ADC最低。     

Influence of temperature on protein utilization in juvenile European seabass (Dicentrarchus labrax)

The aim of this trial was to study the utilization of dietary protein by seabass juveniles with 5.5 g mean body weight, at two water temperatures: 18°C and 25°C. For that purpose, the fish were fed for 12 weeks, four isoenergetic diets with different protein levels (36, 42, 48, and 56%). At the end of the trial, growth rate and feed utilization were significantly better at the higher water temperature. Within each temperature, specific growth rate and feed efficiency were significantly higher with the 48 and 56% protein diets than with the other diets. At 25°C, feed efficiency was also significantly better with the 56% than with the 48% protein diet. N retention (g kg average body weight⁻¹ day⁻¹) was higher at 25°C than at 18°C but, as a % N intake the inverse was true. Although at 25°C N retention (% N intake) was not different among groups, retention in g kg ABW⁻¹ day⁻¹ was significantly higher with the 56% protein diet than with 36 and 42% protein diets. On the contrary, at 18°C N retention (g kg ABW⁻¹ day⁻¹) was similar among groups while as a percentage of N intake it was inversely related to the dietary protein level. Regarding energy utilization, at each temperature, there were no differences among dietary treatments on energy retention (g kg ABW⁻¹ day⁻¹). As a % of energy intake, energy retention significantly increased with the increase of dietary protein level at 25°C, while at 18°C, there were no significant differences among groups. Within each temperature, at the end of the trial, there were no differences among groups in proximate composition of whole fish. Apparent digestibility coefficients of dry matter, protein and energy significantly improved with the increase of water temperature but, within each temperature, there were no significant differences among groups. The results of this study indicate that, regardless of water temperature, the dietary protein requirement for growth seems to be satisfied with a diet containing 48% protein. Growth and feed efficiency were significantly higher at the higher temperature, however, protein utilization was more efficient at the lower temperature.     

Effects of dietary protein to carbohydrate ratios on growth and body composition of juvenile yellow catfish, Pelteobagrus fulvidraco (Siluriformes, Bagridae, Pelteobagrus)

The present experiment was conducted to investigate the effects of dietary protein to carbohydrate ratios on growth and body composition of juvenile yellow catfish, Pelteobagrus fulvidraco . Nine diets were formulated to contain three protein levels (30%, 36% and 42%), each with three carbohydrate levels (24%, 30% and 36%). Each diet was randomly assigned to triplicate groups of 20 fish (initial mean body weight: 8.24±0.20 g) in indoor flow – through fibreglass tanks. The experiment continued for 8 weeks. Weight gain and specific growth rate were similar for the fish fed the 36% and 42% protein diets but higher than that fed the 30% protein diet. At the 36% protein level, carbohydrate contents varying from 24% to 36% ( P / E ratio of 24.0–28.2 mg protein kJ⁻¹) had no significant effects on growth performance and feed utilization ( P >0.05). Protein efficiency ratio tended to increase with dietary carbohydrate level at the same protein level. Dietary treatments significantly influenced body composition ( P <0.05), but not the condition factor, viscerosomatic index, hepatosomatic index and intraperitoneal fat ratio ( P >0.05). Based on these observations, 36% protein and 24–36% carbohydrate with the P / E ratio of 24.0–28.2 mg protein kJ⁻¹ seemed suitable for optimal growth and feed utilization, and carbohydrate could cause protein-sparing effect in diets for juvenile yellow catfish.