饲料中补充晶体或微囊赖氨酸对草鱼生长和血浆总游离氨基酸的影响

为考察饲料中补充晶体或微囊赖氨酸对草鱼生长性能的影响,配制了豆粕含量为23%(高豆粕组),15%(低豆粕组)的两种实用饲料,在低豆粕饲料中补充晶体赖氨酸或微囊赖氨酸,使赖氨酸达到与高豆粕组一致的水平,共4个处理组,即高豆粕组、低豆粕组、低豆粕+晶体赖氨酸(晶体赖氨酸组)、低豆粕+微囊赖氨酸(微囊赖氨酸组),每处理设3个平行。饲养平均体重为(49.0±2.0)g的草鱼8周。结果表明,各组鱼体增重率分别为279.3%、239.7%、245.6%、277.5%,饲料系数为1.62、1.88、1.85、1.62。与低豆粕组相比,添加晶体赖氨酸对草鱼生长无改善(P>0.05),而添加微囊赖氨酸则提高草鱼增重率15.8%(P<0.05),降低饲料系数0.24(P<0.05),在增重率与饲料系数方面达到与高豆粕组基本一致的水平(P>0.05)。对草鱼摄食上述4种饲料0、1、2、3、4、5h后的血浆总游离氨基酸浓度测定结果表明,添加微囊赖氨酸血浆总游离氨基酸的变化趋势与高豆粕组、低豆粕组一致,即在饲后3h达到高峰,而添加晶体赖氨酸使血浆总游离氨基酸的吸收峰值提前。晶体赖氨酸经微囊化后,其水中溶失率显著降低(P<0.05),仅...     

肉骨粉替代鱼粉对吉富罗非鱼生长、体组成、消化和非特异性免疫能力的影响

为研究肉骨粉替代鱼粉对罗非鱼(Oreochromis niloticus)生长性能、体组成、消化酶活性和免疫能力的影响,设计通过调节油脂以及补充包膜赖氨酸、蛋氨酸,分别形成等氮、等脂、等赖氨酸、等蛋氨酸的日粮,进行饲养比较试验。试验分4组,对照组(D1)饲料鱼粉含量为12%,试验组(D2~D4)饲料肉骨粉分别替代鱼粉33.33%(D2)、66.67%(D3)、100%(D4)。试验选取体重(24.91±0.06)g的罗非鱼360尾,随机分为4组,每组3个重复,每个重复30尾,试验期为56 d。结果显示:试验组(D2~D4)增重率、特定生长率和饲料系数、内脏比、肥满度、全鱼水分、粗蛋白质与对照组差异不显著,全鱼粗脂肪含量逐渐下降。肉骨粉替代鱼粉33.33%、66.67%和100%后,胃蛋白酶活性显著高于对照组,肠蛋白酶活性与对照组差异不显著;替代组肠淀粉酶活性显著低于对照组,替代组之间差异不显著;肠脂肪酶活性差异不显著。罗非鱼对肉骨粉的干物质、蛋白及脂肪的表观消化率都显著低于鱼粉。血清超氧化物歧化酶(SOD)和溶菌酶(LYZ)在66.67%替代组最高,显著高于对照组和33.33%、100%替代组;丙二醛(MDA)含量66.67%替代组最低。肉骨粉替代鱼粉66.67%可以显著提高罗非鱼抗氧化能力和免疫能力。结果表明:罗非鱼日粮中肉骨粉替代鱼粉不影响罗非鱼的生长性能、体组成,不会降低胃、肠蛋白酶活性及机体免疫能力,可以全部替代鱼粉。     

杂交罗非鱼饲料中豆粕、发酵豆粕和晶体氨基酸替代鱼粉的研究

添加豆粕(soybean meal,SBM)、发酵豆粕(fermented soybean meal,FSBM)和晶体氨基酸(crystalline amino acid,CAA)替代杂交罗非鱼(Oreoehromis niloticus ♀×O.aureus ♂)实用饲料中5%的鱼粉,连续投喂初始体重为9.41±0.05 g的罗非鱼9周后,通过测定罗非鱼的增重率(WGR,%)、特定生长率(SGR,%)、饲料效率(FE,%)、蛋白质效率(PER,%),并进行肝脏分析和血浆分析,比较各组饲料对罗非鱼生长和非特异性免疫的影响.结果表明,发酵豆粕+晶体氨基酸组的WGR、SGR高于其他3组,鱼粉组的FE高于其他3组;PER方面各组间差异不显著,4组饲料对罗非鱼肝脏组成、血浆成分和存活率没有造成显著差异.     

不同添加量发酵棉粕作为蛋白饲料对恩施黑猪育肥性能的影响研究

目的 研究不同添加量发酵棉粕作为蛋白饲料对恩施黑猪育肥性能的影响。方法 试验选取44头3月龄恩施黑猪为供试对象，随机平均分为4组，对照组以普通豆粕作为蛋白质饲料，试验Ⅰ、Ⅱ和Ⅲ组分别以5%、7.5%和10%的发酵棉粕替代部分豆粕作为蛋白饲料，试验期5个月，试验期结束后测定并对比各组日增重、日采食量和料肉比。结果 在日增重方面，试验Ⅰ组低于对照组(P>0.05),试验Ⅱ和Ⅲ组高于对照组(P>0.05);在日采食量方面，试验组采食量均有所增加，试验Ⅲ组增加最多，但差异不显著(P>0.05);在料肉比方面，相对于对照组3个试验组均有不同程度下降，试验Ⅲ组与对照组之间差异显著(P<0.05)。结论 使用10%发酵棉粕替代10%普通豆能够满足恩施黑猪育肥期生长需求，育肥效果最佳。     

低聚木糖对奥尼罗非鱼幼鱼生长、体成分和消化酶活力的影响

研究了在(27.0±1)℃条件下,饲料中添加不同水平的低聚木糖(0.015%、0.030%、0.045%、0.060%)对初始体重为(6.29±0.94)g的奥尼罗非鱼(Oreochromis niloticus×O.aureus)幼鱼生长、饲料转化率、体成分和消化酶活性的影响。共设5个试验组,每组设3个重复,每个水族箱内随机放幼鱼12尾,投喂率为6%,自然光周期,循环过滤水系统饲养8周。结果显示:添加0.030%低聚木糖组的特定生长率显著高于对照组(P<0.05);0.030%和0.045%低聚木糖组的饲料转化率显著高于对照组(P<0.05),两组之间差异不显著。奥尼罗非鱼幼鱼全鱼的水分、灰分、粗蛋白和粗脂肪含量在试验组间差异不显著(P>0.05);各组样本中的肝胰脏蛋白酶和肠蛋白酶活力均呈先上升后下降的趋势,0.030%组的最高,添加低聚木糖组与对照组之间差异显著(P<0.05);肠淀粉酶和脂肪酶活力在分别在0.030%与0.045%组最高,各组之间差异显著(P<0.05);肝胰脏淀粉酶和脂肪酶活力在各组之间差异不显著(P>0.05)。低聚木糖添加量(x)与特定生长率(y)之间存在关系:y=-256.34x2+16.716x+3.6479(R2=0.9266),低聚木糖添加量在0.033%左右时,可以提高幼鱼的消化酶活力和饲料转化率,从而较好促进奥尼罗非鱼幼鱼的生长,对鱼体的营养成分则没有影响。     

饲料菜粕水平对吉富罗非鱼幼鱼生长、肝脏组织结构和部分非特异性免疫指标的影响

分别用15.0%(对照组)、30.0%、45.0%、60.0%、75.0% 的菜粕配制5种等氮(粗蛋白质为34.0%)等能(总能为19.2 kJ/g)饲料,饲养吉富罗非鱼幼鱼［初始体质量(4.82±0.46) g］10周,考察饲料中不同菜粕水平对吉富罗非鱼生长、肝脏组织结构和部分非特异性免疫指标的影响。结果表明,吉富罗非鱼的增重率、特定生长率、饲料效率和蛋白质效率随着菜粕水平的增加呈下降趋势,且60.0%和75.0%组显著低于对照组(P<0.05),30.0% 和45.0% 组与对照组无显著性差异(P>0.05);各处理组之间的肝体比、脏体比和成活率无显著性差异(P>0.05)。吉富罗非鱼全鱼营养成分,60.0% 组粗蛋白质含量显著高于对照组(P<0.05),60.0%组粗脂肪含量显著低于30.0%(P<0.05),各处理组水分和灰分无显著性差异(P>0.05)。吉富罗非鱼肝细胞核偏移和空泡变性的数量随着菜粕水平的增加逐渐增加,肝脏组织结构受损程度加剧。血清碱性磷酸酶活性随着菜粕水平的增加不断升高,且75.0%组显著高于对照组(P<0.05),血清超氧化物岐化酶活性随着菜粕水平的增加而下降,60.0%组最低,与对照组差异显著(P<0.05)。在本试验条件下,吉富罗非鱼幼鱼饲料中菜粕的使用量不宜超过45.0%。     

添加松针粉对肉鸡营养物质代谢率的影响

选用18日龄肉鸡80羽,随机分为4组,分别为组Ⅰ、组Ⅱ、组Ⅲ、组Ⅳ,其中组Ⅰ、组Ⅱ、组Ⅲ为试验组,组Ⅳ为对照组。每组5个重复,每个重复4羽(♀)。采用单因子随机分组设计,共设4个处理,组Ⅰ为基础饲料+1%松针粉,组Ⅱ为基础饲料+3%松针粉,组Ⅲ为基础饲料+5%松针粉,对照组为基础饲料+抗生素。研究结果表明,干物质表观代谢率组Ⅰ、组Ⅱ与对照组之间无显著性显著(P>0.05),但组Ⅲ干物质表观代谢率显著低于对照组(P<0.05),5%松针粉组干物质代谢率比对照组低5.46%,其余各组间无显著性差异(P>0.05);粗蛋白质日摄入量及日排出量各组间均无显著性差异(P>0.05);粗蛋白质表观代谢率组Ⅰ、组Ⅱ、组Ⅲ显著高于对照组(P<0.05),组Ⅰ、组Ⅱ、组Ⅲ分别比对照组提高了18.34%、23.44%、27.13%;粗脂肪日摄入量组Ⅲ显著高于组Ⅰ和对照组(P<0.05),试验组之间无显著性差异(P<0.05);粗脂肪日排出量组Ⅲ显著高于组Ⅰ、组Ⅱ及对照组(P<0.05),其余各组间无显著性差异(P>0.05);粗脂肪的表观代谢率组Ⅰ、组Ⅱ显著高于对照组(P<0.05),其余各组间无显著性差异(P>0.05),粗脂肪的表观代谢率组Ⅰ、组Ⅱ、组Ⅲ分别比对照组提高了6.86%、9.43%、5.05%;磷的日摄入量、日排出量、表观代谢率各组间无显著性差异(P>0.05)。     

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)。     

红鳍东方鲀对8种饲料原料的表观消化率

本研究旨在探讨红鳍东方鲀(Takifugu rubripes)幼鱼对红鱼粉、白鱼粉、豆粕、菜粕、花生粕、棉粕、玉米酒糟蛋白(DDGS)和肉骨粉中干物质、粗蛋白、粗脂肪、氨基酸、总能和总磷的表观消化率。实验饲料由70%的基础饲料和30%的待测饲料原料组成，并添加0.1%的三氧化二钇(Y2O3)作为外源添加剂，选取平均体重为37.90 g的红鳍东方鲀幼鱼，随机分成8组，每组3个重复，每个重复30尾鱼，按照不同处理分别投喂相应饲料，采用虹吸法收集粪便。结果显示，白鱼粉、红鱼粉和豆粕的干物质表观消化率分别为70.54%、69.02%和60.37%，显著高于菜粕、棉粕及DDGS(P<0.05)；粗蛋白的表观消化率为50.91%~92.78%，肉骨粉粗蛋白表观消化率最低(50.91%)，显著低于白鱼粉、红鱼粉、豆粕、菜粕、花生粕和DDGS(P<0.05)，各待测饲料原料中总氨基酸表观消化率的变化趋势与粗蛋白的表观消化率基本一致；粗脂肪的表观消化率为70.6%~94.19%，白鱼粉粗脂肪表观消化率最高(94.19%)，显著高于棉粕和肉骨粉(P<0.05)；能量的表观消化率为30.58%~90.01%，白鱼粉、红鱼粉、豆粕和花生粕总能的表观消化率最高(76.26%~90.01%)(P<0.05)；磷的表观消化率为9.13%~68.14%，白鱼粉和红鱼粉的总磷表观消化率最高(分别为66.98%和68.14%)(P<0.05)。白鱼粉、红鱼粉的各种营养成分的表观消化率均较佳，肉骨粉及棉粕各种营养成分的表观消化率相对较差；豆粕及花生粕的粗蛋白消化率及必需氨基酸的消化率优于其他植物蛋白，菜粕次之。     

芽孢杆菌有氧发酵豆粕替代鱼粉对大口黑鲈幼鱼生长性能、血清生化指标及肠组织结构的影响

芽孢杆菌(Bacillus)有氧发酵豆粕的肽类和活菌等含量丰富，为研究其替代鱼粉对大口黑鲈(Micropterus salmoides)幼鱼的养殖效果，配制鱼粉含量为50%的大口黑鲈基础饲料，在基础饲料中用芽孢杆菌有氧发酵豆粕分别替代0、10%、20%、30%和40%的鱼粉，配制成5种等氮、等能实验饲料进饲养实验。实验共分5个组，每组3个重复，每个重复30尾鱼[初始体重为(19.83±0.33) g]。采用表观饱食投喂饲养75 d。结果显示，20%和30%实验组增重率显著高于对照组(P<0.05)，但饲料效率、存活率与对照组无显著差异(P>0.05)，20%的替代组增重率及饲料效率皆出现最大值；各实验组之间肥满度和肝体比均无显著差异(P>0.05)，但替代组脏体比出现下降的趋势，且当替代量超过30%时，显著低于对照组(P<0.05)。血清白蛋白含量各组间无显著性差异(P>0.05)，替代组总蛋白和球蛋白的含量显著高于对照组(P<0.05)谷丙转氨酶和谷草转氨酶活力随鱼粉替代量的增加而显著升高，10%组与对照组无显著差异(P>0.05)，其他各替代组显著高于对照组(P<0.05)。对肠道组织结构的研究结果显示，40%组前肠肠绒毛密度和肠壁厚度均显著低于对照组；30%前肠绒毛高度和宽度显著高于其他各组(P<0.05)。10%组中肠肠壁厚度显著高于对照组(P<0.05)，但与其他各实验组与对照组无显著差异(P>0.05)；20%和40%组中肠绒毛密度和高度显著低于对照组(P<0.05)。各实验组的后肠肠壁厚度显著低于对照组(P<0.05)，但30%组绒毛高度和宽度均显著高于对照组(P<0.05)。综上所述，在本实验条件下，芽孢杆菌有氧发酵豆粕替代20%的鱼粉不会影响大口黑鲈的生长性能和体质，对其肠道健康有一定的促进作用。     

复合动植物蛋白部分替代鱼粉对大菱鲆幼鱼生长、体成分及生理生化指标的影响

本研究设计5组等氮等能(粗蛋白为53%,能量为25KJ/g)的实验饲料,以60%的鱼粉饲料组作为对照(D1),豆粕∶花生粕∶鱼溶浆粉∶鸡肉粉(2∶1∶3∶2)的复合蛋白替代40%(D2)、50%(D3)、60%(D4)和70%(D5)的鱼粉,养殖大菱鲆幼鱼(Scophthalmus maximus L.)初始体重(53.0±0.2) g,养殖周期84 d,每天定时(08:00,16:30)投喂2次,投喂量为体重的1.5%～2%。实验结果显示,各处理组之间幼鱼存活率、饲料系数和摄食率均无显著性差异(P0.05);与对照组相比,D4和D5组增重率显著降低(P0.05);肥满度在D2组达到最高值,显著高于D3、D4和D5组(P0.05);脏体比(VSI)、肝体比(HSI)和肠体比(ISI)均在D2组达到最低值,均显著低于D5组(P0.05);复合动植物蛋白替代鱼粉对大菱鲆幼鱼全鱼水分和粗蛋白含量均无显著影响(P0.05);各替代组全鱼粗脂肪含量显著高于对照组(P0.05);全鱼灰分含量在D5组显著低于对照组(P0.05);各组间背肌水分、粗蛋白、粗脂肪和灰分含量均无显著性差异(P0.05);复合动植物蛋白替代鱼粉对鱼体肌肉非必需氨基酸和必需氨基酸总量无显著影响(P0.05);各替代组均显著提高了血清谷草转氨酶和谷丙转氨酶活性(P0.05);总蛋白浓度在D2组显著高于D4和D5组(P0.05);血糖浓度在D2和D3组显著低于其他3组(P0.05);D3、D4和D5组甘油三酯浓度和高密度脂蛋白浓度均显著低于对照组和D2组(P0.05);各替代组胆固醇和低密度脂蛋白浓度均显著低于对照组(P0.05);各组之间碱性磷酸酶浓度无显著差异(P0.05)。研究结果表明,复合动植物蛋白可有效替代50%鱼粉而不影响大菱鲆幼鱼生长性能和部分生理生化指标。     

Influence of multiple amino acid supplementation on the performance of rainbow trout, Oncorhynchus mykiss (Walbaum), fed soya based diets

Using rainbow trout, Oncorhynchus mykiss (Walbaum), of approximately 50 g, a 63 day feeding trial was undertaken to evaluate the efficacy of individual and multiple amino acid supplements in diets where soyabean meal was used as the principle protein source. Iso-nitrogenous diets (45% crude protein) were formulated where the control diet (F) contained fishmeal as the reference protein and a solvent extracted soyabean meal (S) replaced approximately 66% of this protein source. The soyabean containing diets were then supplemented with crystalline amino acids thus; methionine only, dual supplemented with two methionine and lysine levels and finally, a supplement comprising methionine, lysine, tryptophan, threonine, arginine and histidine. The results showed that soyabean meal (SBM) was inferior to the reference protein when SBM was used to replace 66% of the fishmeal and that no significant restoration in growth, feed efficiency and apparent net protein utilization was obtained by either methionine only or dual methionine and lysine supplementation. However, by comparison with the fish fed the unsupplemented, single and dual supplemented diets, multiple amino acid incorporation was associated with significantly improved percentage weight gain, specific growth rate and marginal improvements in apparent net protein utilization. However, performance was not equal to that of the fish fed the fishmeal based control diet. The results are discussed with respect to the level of each of the essential amino acids (EAA) as a proportion of the total EAAs (A/E index) of test diets by reference to the whole body tissue amino acid profile of rainbow trout.     

Partial replacement of fish meal by soybean meal with or without methionine and phytase supplement in diets for juvenile Chinese sucker,Myxocyprinus asiaticus

This study was designed to evaluate the effects of using soybean meal supplemented with or without methionine (M) and graded levels of phytase (P) to replace high‐level (60%) fish meal in the diets for juvenile Chinese sucker. Seven experimental diets (about 430 g kg^?1 crude protein on dry matter basis) were formulated from practical ingredients. The control diet (FM) was formulated to contain 400 g kg^?1 white fish meal (FM), whereas in the other six diets (diets 2–7), soybean meal (SBM) was used to replace 60% fish meal with or without methionine (3 g kg ^?1) and 0,500, 1000, 1500 and 2000 U kg^?1 phytase (designated as SBM, SM, SMP500, SMP1000, SMP1500 and SMP2000, respectively). Results from the feeding trial indicated that SBM without any methionine or phytase supplement replacing about 60% FM significantly affected the growth of fish (P < 0.05). Weight gain of fish fed diet SM was significantly higher than the fish fed diet SBM, but still much lower than fish fed the control diet (P < 0.05). SBM with methionine and phytase supplement significantly improved the growth of fish and apparent digestibility coefficients of phosphorus compared with the groups which fed diet SBM and diet SM (P < 0.05). Weight gain of fish fed SMP1000, SMP1500 and SMP2000 had no significant difference than fish fed control diet. Furthermore, fish fed SMP1500 showed optimum weight gain and ADC of phosphorus between these three groups. This suggested that soybean meal with 3 g kg^?1 methionine and 1500 U kg^?1 phytase supplement could successfully replace 60% fish meal in the diet for juvenile Chinese sucker without affecting growth and enhanced the apparent digestibility coefficient of phosphorus.     

Growth performance and feed utilization of Nile tilapia Oreochromis niloticus (Linnaeus, 1758) and tilapia galilae Sarotherodon galilaeus (Linnaeus, 1758) fingerlings fed plant protein-based diets

This study was designed to determine the effect of complete substitution of fish meal (FM) by three plant protein sources including extruded soybean meal (SBM), extruded full‐fat soybean (FFSB) and corn gluten meal (CGM) on growth and feed utilization of Nile tilapia Oreochromis niloticus and tilapia galilae Sarothrodon galilaeus. Four isonitrogenous of crude protein (ca. 28.0%) and isocaloric (ca. 19 MJ kg⁻¹) experimental diets were formulated. The control diet (diet 1) was prepared with FM as the main protein sources. Diets 2–4, each FM control diet, were completely substituted with SBM (diet 2), FFSB (diet 3) and CGM (diet 4). l ‐lysine and dl ‐methionine were added to plant protein diets to cover the nutritional requirements of tilapia. Each treatment was allocated to three net pens and fed for 17 weeks. Nile tilapia fed the control diet showed significantly higher (P≤0.05) values for final body weight (FBW), feed intake (FI), weight gain (WG) and specific growth rate (SGR), whereas fish fed the diet with CGM achieved the lowest values. Tilapia galilae fed SBM diet recorded the highest (P≤0.05) values for growth performance. Better feed conversion ratio (FCR) for both Oreochromis niloticus and Sarothrodon galilaeus was observed when fish were fed SBM diet, whereas the worse FCR was recorded for FFSB diet. Feed utilization parameters including protein productive value (PPV), fat retention (FR) and energy retention (ER) showed significant differences (P≤0.05) for both the species fed different dietary protein sources. The present results suggest that, for Nile tilapia, both SBM and FFSB supplemented with dl ‐methionine and l ‐lysine can completely replace dietary FM. Meanwhile, S. galilaeus fed SBM diet exhibited comparable growth and feed utilization with those fish fed a fish‐meal‐based diet.     

Improvement of quality of sesame Seasamum indicum seed meal protein with supplemental amino acids in feeds for rohu Labeo rohita (Hamilton) fingerlings

An 8-week feeding trial was conducted in a static indoor rearing system to examine the effects of partial substitution of fish meal (FM) protein with sesame seed meal protein with and without supplemental amino acids in diets for rohu Labeo rohita fingerlings (average weight 3.82 ± 0.05 g). Before incorporation into diets, sesame Seasamum indicum seed meal was fermented with lactic acid bacteria Lactobacillus acidophilus in order to reduce/eliminate the antinutritional factors tannin and phytic acid present in it. Twelve experimental diets (diets D1 to D12) were formulated replacing the FM protein from a reference diet with sesame seed meal protein at different levels (four sets of diets, of which each set of three diets contained 30%, 40% and 50% replacement of FM protein by sesame seed meal protein respectively). Diets D1 to D3 were not supplemented with any amino acid. Lysine was supplemented to diets D4 to D6. Diets D7 to D9 were supplemented with methionine–cystine (together), and diets D10 to D12 contained lysine and methionine–cystine (together). Lysine and methionine–cystine were added to the diets at 5.7% and 3.1% of dietary protein respectively. The groups of fish fed diets without any supplemental amino acids had significantly lower percentage weight gain, specific growth rate (SGR) and higher feed : gain ratio (FGR) than the groups of fish fed on other experimental diets. The addition of lysine and methionine–cystine to the diet in which 50% of FM protein was replaced by sesame meal protein (diet D12) significantly improved fish weight gain and FGR. The percentage live weight gain and SGR values differed significantly (P < 0.01) from each other in the fish fed diets D10 to D12, which were supplemented with all three amino acids. The results of the present study suggest that rohu fingerlings can effectively utilize the supplemented amino acids and that sesame seed meal protein can replace up to 50% of FM protein in the diets for rohu if the sesame seed meal is properly processed (fermented) and supplemented with deficient amino acids.     

Effects of Replacement of Fish Meal by Soybean Meal and Supplementation of Methionine in Fish Meal/Soybean Meal-based Diets on Growth Performance of the Southern Catfish Silurus meridionalis

Two experiments (Experiment I and 11) were conducted to evaluate the effects of dietary soybean meal (SBM) with or without supplementation of methionine on the growth performance of the southern catfish Silurus meridionalis. Fish were fed isonitrogenous (48% crude protein) and isoenergetic (20 KJ/g gross energy) diets for 8 wk in a recirculating rearing system. In Experiment I, six diets containing 0.0,11.6, 23.1, 34.7, 46.3, and 57.9% solvent‐extracted SBM as replacement of 0% (control), 13%, 26%, 39%, 52% and 65% fish meal (FM) protein were formulated to examine the effects of dietary SBM on growth performance. Each of the six diets was randomly fed to triplicate tanks, and each tank was stocked with 10 fish (average initial weight 23.78 ± 0.09 g). Fish fed the diets with 13%, 26%, and 39% protein from SBM had significantly higher or similar specific growth rate (SGR) compared with the control group. However, SGR in fish fed the diets with 52% and 65% protein from SBM was significantly lower than other groups (P < 0.05). These results showed that 39% of FM protein could be replaced by SBM protein in diets of the southern catfish without significantly reducing growth. In Experiment II, seven diets were formulated to examine the effects of supplemental methionine on the growth performance of this fish (initial weight of 19.73 ± 0.36 g) fed diets at the two SBM substitution level (SL) for replacing 39% or 52% FM protein. The control diet was the same as that (0% SL) in Experiment I. Three methionine levels (0.00%, 0.12%, or 0.26% at 39% SL, 0.00%, 0.21%, or 0.33% at 52% SL) were separately supplemented to represent two endogenous controls (no methionine supplementation), and to produce diets with the same methionine content as that found in either the body carcass of this fish or the control diet (0% SBM protein), respectively. The results showed that there were no significant differences in feeding rate, digestibility and SGR between fish fed the diets with and without supplementation of methionine at 39% SL. However, supplementation of methionine at 52% SL results in significantly higher SGR and feed efficiency (FE) than that of fish fed the diet without supplementation (P < 0.05). It is suggested that the endogenous methionine content in the diet at 39% SL could meet the requirement for the growth, but is insufficient at 52% SL. The results of the present study indicate that methionine is one of the limiting factors in SBM‐based diets to growth of the southern catfish, and supplementation of methionine into diets containing a high content of SBM could improve the growth performance of this fish.     

Growth and Body Composition of Nile Tilapia,Oreochromis niloticus,Fry Fed Organic Diets Containing Yeast Extract and Soybean Meal as Replacements for Fish Meal,with and without Supplemental Lysine and Methionine

Quantities of fish meal (FM) have remained level for the past several decades; however, demand has dramatically increased because of its inclusion in all animal production as a high‐quality protein source. Soybean meal (SBM) is the most widely used plant‐protein ingredient for replacing various proportions of FM in aquatic animal diets. However, use of SBM as the sole protein source has often resulted in reduced fish growth. There is a growing segment of consumers who desire organically grown seafood, and tilapia is one of the most‐cultured fish in the world. As tilapia have herbivorous/omnivorous feeding habits, tilapia fed organic diets may allow producers to enter this rapidly developing market. A feeding experiment was conducted to evaluate the combination of organic SBM and an organic yeast extract (YE) as complete replacements for FM in Nile tilapia, Oreochromis niloticus, fry diets. Nine diets were formulated to contain various percentages of organic YE (0, 15, 30, and 45%) in combination with organic SBM (84–34%) with and without amino acid (methionine and lysine) supplementation. At the conclusion of the study, fry fed a control diet containing 20% FM and fry fed a diet containing 45% YE/36%SBM with amino acid supplementation showed no significant differences (P > 0.05) in final weight, weight gain, and specific growth rate (SGR) compared to those fed all other diets. On the basis of these data, an organic diet which replaces FM with a combination of SBM and YE with added methionine and lysine is commercially feasible and further investigation into the increased use of these two ingredients as protein sources in aquaculture diets is warranted.     

Replacement of Fishmeal with Soybean Meal in Male Tilapia (Oreochromis niloticusxO. aureus) Fingerling Diets at a Suboptimal Protein Level

A feeding trial was conducted to study the feasibility of using soybean meal (SBM) to replace fish meal (FM) as a protein source for tilapia feeds containing 24% dietary protein. Replacement levels were 0%, 33%, 67% and 100%. At each replacement level, methionine was either supplemented up to the amount that the 100% FM protein diet contained or not supplemented. The experiment was carried out for eight weeks in a recirculated water system. Fish fed diets in which 100% of the FM was replaced with SBM either with or without methionine supplementation had significantly ( P < 0.05) lower weight gain, feed conversion ratio, protein efficiency ratio and protein digestibility than that of the groups fed the diets containing FM as the sole source of protein. Also, fish fed diets in which 67% and 33% of the FM was replaced with SBM did not differ significantly ( P > 0.05) from that of the control group. These data suggest that when dietary protein level was suboptimal (24%), up to 67% of the FM protein in tilapin feeds can be replaced by hexane-extracted SBM protein without any adverse effect on tilapia growth and feed conversion ratio.     

Optimization of the supplemental essential amino acids to a fish meal-free diet based on fermented soybean meal for rainbow trout <Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>

To minimize the supplemental essential amino acids (EAAs) to a fish meal-free diet for rainbow trout Oncorhynchus mykiss, four types of fish meal-free diets and a control fish meal-based diet were fed to triplicate groups of trout (initial BW, 16 g) for 10 weeks. Two fish meal-free diets based on a fermented and an unfermented soybean meal were unsupplemented with EAAs (diet FSBM and SBM), and two fish meal-free diets based on the fermented soybean meal were supplemented with a combination of lysine and methionine (diet F + ML) and all EAAs (diet F + All), the EAA contents of which were lower than those of the control diet (diet FM). Although physiological conditions such as the biliary bile acid status and morphological features of fish fed diet FSBM were improved and similar to those of fish fed diet FM, the growth performance was not significantly different (P > 0.05) from fish fed diet SBM. The growth performances and whole body protein contents of fish fed F + ML and F + All diets were similarly improved compared to fish fed diet FSBM. These findings indicate that supplementation of lysine and methionine to a fermented soybean meal-based fish meal-free diet is enough to maximize the amino acid utilization of the diet.     

Replacement of Soybean Meal in Channel Catfish, Ictalurus punctatus, Diets with Cottonseed Meal and Distiller's Dried Grains with Solubles

Two pond experiments were conducted to evaluate cottonseed meal (CSM), distiller's dried grains with solubles (DDGS), and supplemental lysine as replacements for soybean meal (SBM) in channel catfish diets. In Experiment 1, fish fed diets in which SBM was totally replaced with CSM gained similar weight as fish fed control diet, but fish fed CSM diet in Experiment 2 had 9.5% lower weight gain than fish fed control diet. In both experiments, feed conversion increased significantly for fish fed CSM diet. There were no consistent trends in body composition of fish fed CSM diet versus control diet. Fish fed the DDGS + SMB diet had higher (Experiment 1) or similar (Experiment 2) weight gain than fish fed control diet. Feed conversion ratio was significantly lower in both experiments for fish fed SBM + DDGS diet than that of fish fed control diet. Body fat tended to be higher in fish fed SBM + DDGS diet compared to fish fed control diet. It appears that about 50% of SBM can be replaced with CSM + lysine in catfish diets without negatively affecting fish performance. Further, DDGS can be used up to at least 30% when the diet is supplemented with lysine.