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。     

翘嘴红鲌幼鱼对蛋白质的需要量

用酪蛋白和白鱼粉为蛋白源配制7种蛋白含量为32.07%～45.64%的半精制试验饲料,喂养7组3个重复的翘嘴红幼鱼8周。饲养试验在室内玻璃钢水箱中进行,试验鱼每尾平均初始体重2.88±0.22g,水温为25～29℃。结果显示:蛋白质水平为41.05%的试验组的鱼体增重、特定生长率、饲料效率和蛋白质效率等指标均显著高于其它试验组(P<0.05);对特定生长率(Y)和饲料效率(F)二项指标的二次曲线回归分析求得翘嘴红幼鱼饲料蛋白最适值分别为40.94%和41.35%;饲料蛋白水平对鱼体(全鱼)的水分、粗蛋白和粗灰分的含量无显著影响(P>0.05),而较高水平饲料蛋白会使鱼体脂肪含量明显降低(P<0.05)。     

去皮豆粕对幼建鲤生长性能和肠道的影响

幼建鲤(Cyprinus carpiovar.jian)初始体质量(10.29±0.10)g,分别饲喂去皮豆粕蛋白占总蛋白0、25%、50%、75%和100%的等氮饲料代替白鱼粉蛋白,进行为期9周的生长实验。结果表明,随去皮豆粕增加,SGR下降,饲料系数升高。当替代50%时,SGR、肠重和前肠后肠皱襞高度显著降低(P<0.05),饲料系数、中肠后肠溶菌酶含量和抗体水平显著升高(P<0.05);50%~100%大豆蛋白组出现肠道皱襞顶端上皮细胞脱落、固有层白细胞数量增多等症状。由本结果可知,高比例去皮豆粕抑制幼建鲤生长,并使其肠道生长受阻和结构受损从而导致消化吸收能力下降,降低饲料利用率;肠道损伤的原因涉及肠道非特异性和特异性免疫反应;在饲料总蛋白水平为33%时,去皮豆粕在体质量为10~35g幼建鲤饲料中替代白鱼粉蛋白的适宜比例为25%。     

分离大豆蛋白对幼建鲤生长性能及肠道的影响

选择体重为(11.34±0.16) g健康建鲤720尾,平均分成5组,每组3个重复,分别饲喂分离大豆蛋白代替白鱼粉蛋白0、40%、60%、80%和100%的等氮饲料,进行为期9周的生长试验,探讨对其生长性能及肠道的影响.结果表明,与全鱼粉蛋白组相比,当替代60%～100%时,增重、特定生长率、采食量、肠重、肠长和前肠后肠皱襞高度显著降低(P＜0.05),饲料系数显著升高;同时,前、后肠出现上皮顶端细胞脱落、固有层变宽且其中白细胞数量增多等病理症状;当替代80%～100%时,中肠后肠溶菌酶含量显著升高,而中肠、后肠抗体水平分别于替代60%～80%和60%时显著升高(P＜0.05),之后则相对降低.由此可知,与白鱼粉相比,分离大豆蛋白降低幼建鲤生长性能;高比例替代导致肠道生长发育受阻、上皮完整性受损;肠黏膜受损的原因涉及肠道非特异性和特异性免疫反应的变化;以饲料系数为衡量指标所确定的分离大豆蛋白在幼建鲤饲料中代替白鱼粉蛋白的适宜比例为40%.     

石斑鱼配合饲料中发酵豆粕和豆粕部分替代白鱼粉的研究

在浮式海水网箱(1.5m×1m×1.5m)中养殖石斑鱼幼鱼(9.4±0.1g),在等氮(52% CP)基础上进行以发酵豆粕和普通豆粕替代鱼粉的实验, 为期56天.结果显示在石斑鱼饲料中添加14%发酵豆粕,其增重率、特定生长率(SGR)、饲料效率和蛋白质效率与对照组没有显著性差异(P>0.05),以后随着发酵豆粕添加量的上升,这些指标都显著下降(P<0.05).在同样替代水平下,添加21%发酵豆粕组,增重率,SGR,饲料效率和蛋白质效率都比添加20%豆粕组高(P<0.05),表明对海水肉食性鱼类来说,发酵豆粕是一种比豆粕更优良的蛋白源.用折线模型分析增重率随白鱼粉替代水平的变化关系,结果表明在石斑鱼配合饲料中,发酵豆粕替代白鱼粉的最适量为10%.从实际生产的经济效益出发,建议在饲料中添加14%发酵豆粕,对石斑鱼的生长和鱼体组成不会造成显著影响.     

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%。     

不同大豆产品替代鱼粉饲养南美白对虾的试验

分别采用脱皮豆粕、大豆蛋白、发酵豆粕等大豆产品,等氮替代饲料中10%的鱼粉(对照组鱼粉35%,替代组鱼粉25%),饲养体重为0.06 g南美白对虾(Penaeus vannam eiBoone)一个月,结果表明,对照组(35%鱼粉)幼虾的增重率、成活率均最大,为1316%、97.5%;脱皮豆粕组幼虾的增重率为最低,仅783%;哈姆雷特大豆蛋白、比多福大豆蛋白、富肽蛋白(发酵豆粕)组幼虾增重率为1033%、983%、1050%,均显著高于脱皮豆粕组(P<0.05),但低于对照组(P<0.05);对虾体肌肉成分的分析显示,各组幼虾肌肉在水分、蛋白质含量方面没有显著差异。上述结果表明,大豆蛋白和发酵豆粕均为优于脱皮豆粕的鱼粉替代品。     

南极磷虾粉对大菱鲆生长、非特异性免疫及氟残留的影响

以鱼粉、南极磷虾粉和豆粕为蛋白源,以南极磷虾粉蛋白分别替代饲料中的0(对照组)、20%、40%、60%的鱼粉蛋白制成4种等氮等能的饲料,并以此饲料饲喂大菱鲆(37.36±2.12g)56d。试验结果显示,饲料中南极磷虾粉水平对大菱鲆的成活率及特定生长率(SGR)没有显著性影响(P>0.05);对各组的饲料干物质表观消化率均有显著性影响(P<0.05),替代40%组与替代60%组蛋白质表观消化率较对照组有显著性差异(P<0.05);对大菱鲆血清中的碱性磷酸酶(AKP)、酸性磷酸酶(ACP)、溶菌酶及总超氧化物歧化酶(T-SOD)活力无显著性影响(P>0.05)。大菱鲆各组间肌肉中氟残留量没有显著性差异(P>0.05),且肌肉中氟含量均在可食用范围内,大菱鲆各组间骨骼中氟残留量均有显著性差异(P<0.05)。     

紫花苜蓿浓缩叶蛋白替代鱼粉对星斑川鲽幼鱼生长、体组成及血液生化指标的影响

研究了紫花苜蓿浓缩叶蛋白替代0%(S0)、10%(S10)、20%(S20)、30%(S30)、40%(S40)、50%(S50)的鱼粉蛋白对星斑川鲽(Platichthys stellatus)幼鱼生长、体组成及血液生化指标的影响。实验幼鱼体质量(83.0±0.20)g。结果显示:1)当替代比例≤20%时,各组间星斑川鲽幼鱼特定生长率(SGR)、日摄食率(DFI)、饲料效率(FE)和蛋白质效率(PER)均无显著变化,高于此值时呈显著下降(P<0.05)。随饲料中紫花苜蓿浓缩叶蛋白替代鱼粉比例的升高,鱼体肥满度(CF)呈显著下降趋势(P<0.05),而消化道指数(DTI)则呈显著上升趋势(P<0.05);各实验组干物质、蛋白质及脂肪表观消化率均呈直线下降趋势(P<0.05)。以星斑川鲽幼鱼特定生长率(SGR)为参考指标,采用折线回归分析得出,在本实验条件下,星斑川鲽幼鱼获得最佳生长时紫花苜蓿浓缩叶蛋白替代鱼粉蛋白的适宜比例为19.0%。2)紫花苜蓿浓缩叶蛋白替代鱼粉对星斑川鲽幼鱼肌肉水分、蛋白及粗灰分含量未产生显著性影响,肌肉脂肪含量仅S40组显著低于S0和S20组,其他各组间无显著差异;当替代比例小于20%时,肝脏水分呈显著上升趋势(P<0.05),之后趋于平稳(P>0.05)。肝脏粗脂肪变化趋势与此相反。肝脏粗蛋白含量仅表现为S30、S50组显著高于S0组(P<0.05),其他各组无显著差异(P>0.05)。肝脏粗灰分含量不受饲料鱼粉替代比例的影响(P>0.05);全鱼水分呈显著上升趋势(P<0.05),而粗脂肪含量呈显著下降(P<0.05)。S30组全鱼粗蛋白最高,S40组最低(P>0.05),除S30组外,其他各组均与S0组间无显著性差异(P>0.05)。各组间全鱼粗灰分含量变化不显著(P>0.05)。3)当替代比例>20%时,星斑川鲽幼鱼血浆甘油三酯(TG)含量呈显著降低。各组间胆固醇(CHO)含量随紫花苜蓿浓缩叶蛋白的添加呈直线下降趋势(P<0.05)。当替代比例≥20%时,碱性磷酸酶(ALP)活性有下降趋势(P<0.05)。当替代比例分别大于20%和40%时,谷草转氨酶(AST)和谷丙转氨酶(ALT)活性显著升高但各组间差异不显著(P>0.05)。实验鱼血浆溶菌酶(LSZ)活力随鱼粉替代比例的升高呈显著上升(P<0.05)。各实验组间血浆丙二醛(MDA)含量无显著差异,但均低于S0组(P<0.05),超氧化物歧化酶(SOD)活性不受紫花苜蓿浓缩叶蛋白替代鱼粉比例的影响(P>0.05)。结论认为,在本实验条件下,星斑川鲽幼鱼获得最佳生长时紫花苜蓿浓缩叶蛋白替代鱼粉蛋白的适宜比例为19.0%。     

新型蛋白源替代鱼粉对星斑川鲽幼鱼生长、体成分和血液学指标的影响

以新型蛋白源（大豆浓缩蛋白、脱酚棉籽蛋白、喷雾干燥血球蛋白粉等）和脱脂鱼粉为原料，通过调节饲料氨基酸水平，配制出5种等氮等能的饲料D0、D17、D35、D52和D69，养殖星斑川鲽，初始体重为（75.6±0.18） g。其中D0（添加58%脱脂鱼粉）为对照组，D17、D35、D52和D69分别为新型蛋白源替代配方中17%、35%、52%和69%的鱼粉用量。每组饲料设3个平行，共养殖60 d。结果表明：对照组(D0)增重率(WGR)、蛋白质效率(PER)、特定生长率(SGR)分别为141.84%、229.88%和1.47%/d。与D0组相比，D69组WGR、PER和SGR显著降低（P<0.05），分别为107.77%、186.37%和1.22%/d ，D17、D35和D52组与D0组均无显著性差异(P>0.05)。对照组(D0)饲料系数(FCR)为0.80，D69组FCR为0.98，差异显著(P<0.05)；D17、D35和D52组与D0组FCR无显著差异(P>0.05)。随新型蛋白源替代鱼粉量的增加，鱼体消化道指数(DTI)逐渐增大，D0组为2.01%，显著小于D69组(P<0.05)。各组间的肥满度(CF)无显著性差异(P>0.05)。全鱼或肌肉中蛋白质和脂肪含量各组间均无显著差异(P>0.05)。全鱼中灰分含量随鱼粉替代量的增加呈增大趋势；红细胞数目、白细胞数目、血红蛋白含量及血清蛋白含量在各组间无显著差异(P>0.05)，但血细胞比容和溶菌酶活力随新型蛋白源替代鱼粉量的增加呈不同程度的降低。本试验条件下，在星斑川鲽幼鱼配合饲料生产中可用新型蛋白源适当替代鱼粉而不影响养殖对象的生长。     

几种处理对三叶草叶蛋白提取率及蛋白质质量分数的影响

选用三叶草为试验材料,通过单因素试验设计,探讨料液比、加盐量、不同pH值和絮凝温度4个因素对三叶草叶蛋白提取率及蛋白质质量分数的影响。以叶蛋白提取率、蛋白质量分数为指标,以期获得三叶草叶蛋白提取基础参数。试验表明,料水比1:3、加盐量4%、pH值4.0、絮凝温度80℃时三叶草的叶蛋白提取率最高。     

嗜水气单胞菌细胞外膜蛋白及S层蛋白分析

用十二烷酰肌氨酸盐抽提结合超速离心纯化，制备了19株典型嗜水气单胞菌（Aeromonas hydrophila)和1株温和气单胞菌（A.sobria)的主要外膜蛋白（MOMP）。根据SDS-PAGE图谱，将其中的14株菌分为3个MOMP组，I组的主要蛋白带为40kD和43kD，Ⅱ组的主要蛋白带为40kD和50kD,Ⅲ组的主要蛋白为40kD、46kD和50kD.MOMP组和血清型间没有严格的关系。用兔抗嗜水气单胞菌体抗原为第一抗体进行免疫印迹实验。结果显示，所有被试菌株都能产生强阳性反应，其中40kD的蛋白带为大多数菌株所共有，且具有相似的免疫原性，是构成菌体抗原的重要免疫原。用0.2mol/L甘氨酸缓冲液（pH4.0)处理上述菌株培养物，结果仅有嗜水气单胞菌ZY01-g3能够分离到丰富的S层样蛋白，其分子量约为52kD，而分子量约为52kD，而其他菌株未能分离到典型的S层样蛋白，表明S层蛋白的分布有限。     

Soybean protein concentrate as a protein source for turbot Scophthalmus maximus L.

In the first of two experiments, the effect of a gradual substitution of dietary fish meal with soybean protein concentrate (SPC) on growth, feed consumption and protein digestibility was examined in 13 g turbot Scophthalmus maximus. Five isonitrogenous and isoenergetic diets (50% protein and 22 kJ g^?1) containing SPC at protein replacement levels of 0, 25, 50, 75 and 100% were offered by hand twice daily. Growth rates of fish fed diets with zero and 25% replacement were not significantly different, with SGRs of 2.47 and 2.28, respectively. At higher replacement levels, growth rates decreased significantly with SGRs of 2.00, 1.33 and 0.68, respectively. Feed conversion ratios increased with soya replacement, with values of 0.68, 0.75, 0.89, 1.27 and 2.32, respectively, although there was no significant difference between the first two. Feed consumption rates remained constant up to 50% replacement, above which they decreased significantly, possibly because of reduced diet palatability. Apparent protein digestibility (APD) was not affected by the incorporation of SPC and ranged from 82.8 to 87.5%. Results suggest that protein catabolism increases in SPC‐rich diets, possibly because of rapid assimilation and utilization of the methionine supplement. In the second experiment, the importance of amino acid supplements and the beneficial effects of protecting these, either by coating them in protein or incorporating them in a protein–lipid emulsion, was investigated. Growth data provided some indication that the utilization of SPC may be improved by incorporating the methionine and lysine supplement in a protein–lipid emulsion prior to diet preparation, although this finding was not found to be statistically significant (0.1 < P < 0.2).     

Fast growth, protein turnover and costs of protein metabolism in yolk-sac larvae of the African catfish (Clarias gariepinus)

In fish larvae the costs of rapid growth may be accommodated by a decrease in the rate of protein turnover or by a reduction in the costs of protein synthesis. Protein growth, synthesis and degradation were measured in yolk-sac larvae of Clarias gariepinus and the costs of protein synthesis and protein growth were estimated. Growth rates were over 100% protein weight day^-1. Protein synthesis retention efficiency (retained protein per unit of synthesis) was estimated to be 69.6%, a value comparable to that of larger fish. The larvae used 43% of their oxygen consumption for protein synthesis. Nevertheless, protein synthesis costs were close to theoretical minima. Therefore, the high growth rates of catfish yolk-sac larvae seem to be possible through minimisation of the costs of protein synthesis. These low costs are associated with high rates of protein synthesis (138%protein weight day^-1), and elevated RNA concentrations (107 µg RNA mg^-1protein), which together suggest very high RNA efficiencies (12.9 g protein synthesized g^-1RNA day^-1).     

WSSV envelope protein VP51B links structural protein complexes and may mediate virus infection

White spot syndrome virus (WSSV), an enveloped double‐stranded DNA virus, is the causative agent of a disease that has led to severe mortalities of cultured shrimps in Taiwan and many other countries. In the previous study, Penaeus monodon chitin‐binding protein (CBP) and glucose transporter 1 (Glut1), two cell membrane proteins, were found to at least interact with other 10 WSSV envelope proteins including VP51B. These envelope proteins might form a protein complex. According to the known information, VP51B was used to identify its role in the protein complex. Western blotting of the intact viral particles and fractionation of the viral components confirmed that VP51B is one of WSSV envelope proteins. In this study, the protein–protein interaction between VP51B and other WSSV envelope proteins was identified by far‐western blot experiment and VP51B was found to interact with VP24, VP31, VP32, VP39B and VP41A. Furthermore, the in vivo neutralization experiment using recombinant VP51B plus with VP39B showed the best inhibition. These data indicate that VP51B participates in the WSSV protein complex and plays an important role in WSSV infection.     

胭脂鱼幼鱼饲料中适宜的蛋白质含量和能量蛋白比的研究

以酪蛋白作为蛋白源,植物油作为脂肪能量基础来源,用糊精调节能量梯度。添加等量α-淀粉、复合预混料,用羧甲基纤维素（CMC）作为粘合剂,配制成不同梯度的蛋白质和能量的试验饲料。以增重率、蛋白质效率和饲料系数为评判依据,对体重为25.80±0.34g的胭脂鱼适宜蛋白质含量及其能量蛋白比进行了研究。结果表明：胭脂鱼幼鱼配合饲料中的适宜蛋白质含量范围为40～45,饲料的最佳能量蛋白比为460。当试验饲料蛋白质含量为41.15,能量蛋白比为460时,试验胭脂鱼获得最大增重率为73,最低的饲料系数为1.52,以及最高的蛋白质效率为1.65。     

饲料蛋白质水平对拉萨裸裂尻鱼幼鱼肌肉氨基酸及蛋白质代谢的影响

本实验旨在探索饲料蛋白质水平对拉萨裸裂尻鱼(SchizopygopsisyounghusbandiRegan)幼鱼肌肉氨基酸及蛋白质代谢的影响。选用初始体重为(22.42±0.56) g的拉萨裸裂尻鱼540尾,随机分成6组,每组3个重复,每个重复30尾鱼,分别投喂蛋白质水平为20%、25%、30%、35%、40%、45%的实验饲料,养殖时间为60 d。结果表明:随着饲料蛋白水平的增加,拉萨裸裂尻鱼氮摄入量(NI)和绝对氮摄入量(ANI)均呈逐渐升高的变化趋势。氮沉积(ND)、蛋白质效率(PER)、净蛋白质利用率(NPU)均呈先升高后降低的变化趋势。肌肉总必需氨基酸(TEAA)、总呈味氨基酸(TFAA)、总非必须氨基酸(TNEAA)、总氨基酸(TAA)随饲料蛋白的升高呈先升高后趋于稳定的变化趋势。饲料蛋白水平超过30%后,血氨(ammonia)、尿素氮(urea)、白蛋白(ALB)显著升高。总蛋白(TP)在饲料蛋白低于35%时呈逐渐升高的变化趋势。拉萨裸裂尻鱼肝脏谷丙转氨酶ALT、谷草转氨酶AST均呈先升高后趋于稳定的变化趋势,血清ALT呈先降低后升高的变化趋势,血清AST在饲料蛋白含量高于35%后显著升高。综合考虑饲料蛋白利用率、血液总蛋白含量、肝脏及血清转氨酶活性,建议拉萨裸裂尻鱼饲料蛋白含量为30%～35%。     

The interactive effects of dietary protein and energy on feed intake, growth and protein utilization of juvenile mulloway (Argyrosomus japonicus)

The objectives of this study were to describe the interactive effects of varying digestible protein (DP) and digestible energy (DE) contents on the feed intake, growth, protein utilization and whole body composition of juvenile mulloway ( Argyrosomus japonicus ) and to determine the optimal DP : DE ratio for growth. This was achieved by feeding mulloway diets containing one of four different DP levels (250–550 g kg⁻¹) at two DE levels (16 or 21 MJ kg⁻¹). Juvenile mulloway were stocked at each of two different sizes (70 or 200 g) in triplicate groups for each dietary treatment and fed twice daily to apparent satiation over 58 days. The results indicated that feed intake was not governed solely by energy demands but was also dependant on the DP content of the diet. Protein utilization did not improve with diets containing decreasing protein and increasing lipid content indicating that mulloway have a limited capacity to spare DP. Optimal DP content was found to be 444–491 g kg⁻¹ depending on the DE content of the diet and the size of mulloway and is within the range reported for other sciaenid species. The use of formulated diets with 28.6 g of DP MJ DE⁻¹ will achieve optimal growth and protein deposition for 70–275 g mulloway.     

Comparative evaluation of dietary protein levels and plant–animal protein ratios in Macrobrachium rosenbergii (de Man)

The effects of varying dietary protein level (200, 250, 300 and 350 g protein kg^?1 diet) and plant : animal protein ratio (1 : 2, 1 : 1, 1 : 1.5 and 2 : 1) on growth of juvenile Macrobrachium rosenbergii (de Man) with approximately 0.27 g initial body weight were evaluated in two separate 30‐days study using practical diets. Significantly lower survival rate was recorded in prawns fed a diet containing 200 g kg^?1 dietary protein (66.67%) whilst 300 and 350 g kg^?1 protein gave the highest survival (96.67%). Significant differences (P < 0.05) in feed conversion ratio and protein efficiency ratio were recorded among different dietary protein levels. The results of the study showed that highest growth rate and maximum utilization of protein were recorded in prawns fed 300 g kg^?1 dietary protein and further increase in the dietary protein does not have any added advantage. There existed no statistically significant difference (P > 0.05) in the specific growth rate, protein efficiency ratio, weight gain and survival rate among the juveniles of M. rosenbergii fed varying plant–animal protein ratios at 300 g kg^?1 protein. Better‐feed conversion ratio was recorded in diets having a plant to animal protein ratio of 1 : 1 (2.62) followed by 1 : 1.5 (2.66), however there was no significant difference between them (P > 0.05). Based on the present study, it would be possible to replace animal protein by low‐cost plant protein in prawn feed. Better growth performance in juveniles of M. rosenbergii can be achieved by the incorporation of equal proportions of plant and animal protein (A : P = 1) in the diet.