中华绒螯蟹对10种常见饲料蛋白源的表观消化率

使用氧化钇作为指示剂,按照"70%基础饲料+30%实验原料"的原则配制实验饲料,测定了中华绒螯蟹Eriocheir sinensis(63.72±1.67 g)对鱼粉、血粉、水解羽毛粉、肉粉、虾粉、肉骨粉、玉米蛋白粉、棉粕、花生粕和精米糠共10种大宗饲料原料的粗蛋白,能量和必需氨基酸的表观消化率。结果表明,除水解羽毛粉和肉骨粉外,中华绒螯蟹对动物性蛋白源的粗蛋白和能量表观消化率比植物性蛋白源要高,蛋白消化率:血粉>虾粉>鱼粉>肉粉>棉粕>花生粕>精米糠>玉米蛋白粉>水解羽毛粉>肉骨粉;能量消化率:血粉>肉粉>虾粉>花生粕>鱼粉>水解羽毛粉>玉米蛋白粉>肉骨粉>棉粕>精米糠。氨基酸的表观消化率(除了肉粉和精米糠)基本与对蛋白质的表观消化率的变化趋势相似。综合以上,血粉、肉粉、虾粉、花生粕、棉粕和精米糠可作为中华绒螯蟹配合饲料的选择蛋白源。相比之下,中华绒螯蟹对肉骨粉、水解羽毛粉和玉米蛋白粉的消化利用率较低,在生产中应谨慎使用。     

中华鳖日本品系对6种饲料蛋白原料表观消化率的研究

研究了中华鳖日本品系(Pelodiscus sinensis,Japanese strain)幼鳖对蝇蛆蛋白粉、虾壳粉、发酵豆粕、豌豆浓缩蛋白、大豆浓缩蛋白以及玉米蛋白粉的干物质、粗蛋白质、氨基酸、粗脂肪和总能的表观消化率。试验饲料由70%基础饲料和30%待测饲料原料组成,并以0.5%的三氧化二铬(Cr2O3)为外源指示剂。选取平均体重为(14.69±0.55)g的中华鳖日本品系幼鳖180只,随机分成6组,每组3个重复,每个重复10只,投喂试验饲料养殖4周,采用虹吸法收集粪便进行表观消化率测定。结果表明,6组饲料的干物质、粗蛋白质、粗脂肪以及总能表观消化率范围为77.8%~85.6%、73.2%~83.7%、81.2%~91.1%和78.8%~85.6%,其中蝇蛆蛋白粉和发酵豆粕的干物质表观消化率较高,大豆浓缩蛋白的粗蛋白、粗脂肪及总能表观消化率较高;各原料总氨基酸表观消化率在75.8%~86.1%,最高值和最低值分别出现在大豆浓缩蛋白和虾壳粉。     

花鱼骨 鱼种对11种蛋白质饲料原料的消化率

为获得花(鱼骨)对常用蛋白源的可消化性数据,按照"70%基础饲料+30%被测原料"的饲料配制方法,用三氧化二铬指标物,测定了花(鱼骨)鱼种对白鱼粉、褐鱼粉、四海豆粕、加佳豆粕、血粉、蚕蛹粉、啤酒酵母、菜籽粕、棉籽粕、花生粕、玉米蛋白粉等11种蛋白原料干物质和粗蛋白的表观消化率.结果表明:花(鱼骨)对11种原料的干物质和蛋白质表观消化率分别为54.84%～86.96%和69.17%～96.77%.其中自鱼粉、褐鱼粉、血粉以及豆粕、啤酒酵母等的干物质消化率较高,白鱼粉、褐鱼粉及豆粕、花生粕等的蛋白质消化率较高.     

团头鲂对8种非常规饲料原料中营养物质的表观消化率

以0.5%的三氧化二铬(Cr2O3)为指示剂,由70%基础日粮和30%试验原料组成试验日粮研究了团头鲂对膨化羽毛粉、酶解羽毛粉、血粉、蚕蛹粉、玉米蛋白粉、玉米、碎米和大麦8种饲料原料的干物质、粗蛋白、粗脂肪、氨基酸、总磷及总能的表观消化率。试验鱼［平均体质量(250.83±2.12) g ］养殖于室内水族箱中(3.0 m×0.8 m×0.8 m),分别投喂相应的试验饲料1周后采用自排法收粪。结果表明:8种饲料原料的干物质、粗蛋白、粗脂肪、总氨基酸、总磷及总能的表观消化率的范围分别是68.07%～92.69%、81.54%～92.75%、84.82%～103.44%、63.07%～95.56%、41.48%～97.55%、68.91%～97.81%。其中各项营养物质的表观消化率均以玉米蛋白粉最高;4种动物蛋白原料中以蚕蛹粉中营养物质表观消化率最高,血粉次之;除粗脂肪外,酶解羽毛粉的消化率均高于膨化羽毛粉;3种能量饲料中,以大麦的蛋白及氨基酸表观消化率最高,但干物质、粗脂肪及能量的表观消化率均显著低于玉米和碎米。由此可见,玉米蛋白粉和蚕蛹粉分别可作为团头鲂优质的植物蛋白源和动物蛋白源,血粉、羽毛粉可搭配其他饲料少量使用。玉米和碎米能值较高,可作为团头鲂的主要能量饲料,大麦由于氨基酸组成较好,也可适量使用。     

中华绒螯蟹对11种饲料原料蛋白质和氨基酸的表观消化率

以氧化钇(Y2O3)作为指示剂,按照"70%基础饲料+30%试验原料"的原则配制饲料,测定了体重(97.34±7.36) g的中华绒螯蟹对不同饲料原料蛋白质和氨基酸的表观消化率.试验选取鱼粉、血粉、肉骨粉、乌贼内脏粉、虾壳粉、啤酒酵母、豆粕、棉籽粕、菜籽粕、花生粕、玉米蛋白粉共11种商品蛋白质饲料原料.试验结果表明,中华绒螯蟹对不同饲料蛋白源的粗蛋白表观消化率为40.62%～89.75%,其中,鱼粉和血粉组的粗蛋白表观消化率分别为86.07%和89.75%,显著高于其他原料组;而菜籽粕(42.41%)和玉米蛋白粉组(40.62%)的粗蛋白消化率则明显低于其他饲料蛋白源(P＜0.05).其他蛋白源的消化率大小顺序依次为:豆粕(77.94%)＞啤酒酵母(76.90%)＞虾壳粉(74.02%)＞肉骨粉(73.78%)＞棉籽粕(71.63%)＞花生粕(65.90%)＞乌贼内脏粉(63.51%).在动物性蛋白源中,中华绒螯蟹对血粉和鱼粉的氨基酸消化率较高,二者的总氨基酸消化率均高于90%,试验结果还显示,蟹对乌贼内脏粉的氨基酸消化率最低,仅为63.51%;单细胞蛋白源啤酒酵母的总氨基酸消化率(86.77%)高于其他植物性蛋白源;在植物性蛋白源中,对棉籽粕的总氨基酸消化率最高(85.37%),其次是豆粕(79.41%).本研究结果对评价不同饲料蛋白源的营养价值,以及开发中华绒螯蟹氨基酸营养平衡的人工配合饲料提供了参考和依据.     

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。     

花鲈对常用饲料原料中氨基酸和磷的利用率研究

试验以Cr2 O3为指示物 ,以 70 %基础饲料和 30 %的待测饲料原料组成试验饲料 ,在室内流水养殖系统中 ,采用虹吸法收集粪便 ,测定了花鲈对红鱼粉、豆粕、花生粕、菜籽粕、肉骨粉和棉籽粕中蛋白质、氨基酸的表观消化率和磷的利用率。在水温 2 5± 1℃的试验条件下 ,花鲈对鱼粉、豆粕、花生粕和菜籽粕的蛋白质的表观消化率都在 80 %以上。花鲈对原料氨基酸表观消化率的变化与对蛋白质表观消化率的变化相一致 ,除了赖氨酸、缬氨酸、蛋氨酸之外 ,对肉骨粉中表观氨基酸的消化率最低。对饼粕类原料中的含硫氨基酸 (如蛋氨酸 )的表观消化率低于其他氨基酸 ,对鱼粉中的组氨酸、对肉骨粉中的苏氨酸利用率最低。花鲈对鱼粉中磷的利用率最高为 85 5 2 % ,而对菜籽粕、肉骨粉和棉籽粕中磷的利用率很低 ,仅为 8 6 9%～ 2 4 82 %。     

晶体氨基酸提高混合动物蛋白替代花鲈饲料中鱼粉的潜力

实验以鸡肉粉∶牛肉骨粉∶喷雾血球干燥粉∶水解羽毛粉=40∶35∶20∶5的比例组成的混合动物蛋白(animal protein blend,APB)分别直接替代或在补充赖氨酸、蛋氨酸、苏氨酸后替代花鲈饲料中50%、75%、100%的低温干燥鱼粉,研究其对花鲈生长及生理功能的影响。经过8周的饲养后发现,花鲈的生长性能随替代比例的提高而降低;摄食含APB饲料的花鲈,其成活率,摄食率和生长性能均显著低于对照组(P<0.05)。与APB直接替代鱼粉的处理组相比,添加3种必需晶体氨基酸极显著提高了花鲈的生长性能及全鱼蛋白、脂肪、能量含量(P<0.01),显著降低了花鲈的全鱼水分、灰分,肝指数及脏体比(P<0.05)。晶体氨基酸与APB的替代水平对花鲈的生长性能、形体指标及体组成成分存在显著的交互作用(P<0.05)。实验结果表明,(1)混合动物蛋白替代初始体重为13.2 g的花鲈饲料中白鱼粉的比例应小于50%;(2)添加必需晶体氨基酸能显著提高APB在花鲈饲料中的应用潜力;(3)花鲈具备一定的利用晶体氨基酸的能力。     

中华绒螫蟹对11种饲料原料蛋白质和氨基酸的表观消化率

以氧化钇（Y2O3）作为指示剂，按照“70％基础饲料＋30％试验原料”的原则配制饲料，测定了体重（97．34±7．36）g的中华绒螯蟹对不同饲料原料蛋白质和氨基酸的表观消化率。试验选取鱼粉、血粉、肉骨粉、乌贼内脏粉、虾壳粉、啤酒酵母、豆粕、棉籽粕、菜籽粕、花生粕、玉米蛋白粉共11种商品蛋白质饲料原料。试验结果表明，中华绒螯蟹对不同饲料蛋白源的粗蛋白表观消化率为40．62％～89．75％，其中，鱼粉和血粉组的粗蛋白表观消化率分别为86．07％和89．75％，显著高于其他原料组；而菜籽粕（42．41％）和玉米蛋白粉组（40．62％）的粗蛋白消化率则明显低于其他饲料蛋白源（P〈0．05）。其他蛋白源的消化率大小顺序依次为：豆粕（77．94％）〉啤酒酵母（76．90％）〉虾壳粉（74．02％）〉肉骨粉（73．78％）〉棉籽粕（71．63％）〉花生粕（65．90％）〉乌贼内脏粉（63．51％）。在动物性蛋白源中，中华绒螯蟹对血粉和鱼粉的氨基酸消化率较高，二者的总氨基酸消化率均高于90％，试验结果还显示，蟹对乌贼内脏粉的氨基酸消化率最低，仅为63．51％；单细胞蛋白源啤酒酵母的总氨基酸消化率（86．77％）高于其他植物性蛋白源；在植物性蛋白源中，对棉籽粕的总氨基酸消化率最高（85．37％），其次是豆粕（79．41％）。本研究结果对评价不同饲料蛋白源的营养价值，以及开发中华绒螯蟹氨基酸营养平衡的人工配合饲料提供了参考和依据。     

草鱼对17种饲料原料粗蛋白和粗脂肪的表观消化率

试验以Cr2O3为指示物，测定草鱼对进口鱼粉、国产鱼粉、蟹粉、肉粉、肠衣粉、酵母、菜饼、黄菜饼、黑菜饼、双低菜仔粕、豆粕、膨化大豆、芝麻饼、棉粕、玉米胚芽饼、玉米蛋白粉和酒糟粉17种试验原料中粗蛋白和粗脂肪的表观消化率。试验饲料由基础饲料和试验原料以70：30的比例（质量比）混合挤压成硬颗粒饲料。结果表明，草鱼对鱼粉、菜籽饼籽、豆粕和膨化大豆等质量好的蛋白饲料的表观消化率较高、其干物质、脂肪和蛋白质的表观消化率均在80％以上；草鱼对酵母、菜籽饼粕、豆粕和膨化大豆等饲料的干物质、脂肪和蛋白质的表观消化率均与鱼粉一致。     

Alternative protein sources in diets for Japanese flounder Paralichthys olivaceus (Temminck and Schlegel): II. Effects on nutrient digestibility and digestive enzyme activity

An 8‐week feeding trial was conducted to compare the effects of dietary protein sources on nutrient digestibility and digestive enzyme activity. Four experimental diets were formulated to contain one of the following as the sole protein source: fish meal (FM), fish protein concentrate (FPC), soy protein concentrate (SPC) and soy protein isolate (SPI). Each diet was randomly assigned to triplicate aquaria stocked with 25 Japanese flounder (Paralichthys olivaceus) each. The dry matter, crude protein and energy digestibility and individual amino acid availability of the SPC‐based diet were significantly lower than those of the other diets. The crude lipid digestibility of soy protein‐based diets was significantly lower than that of the FM‐based diet. The pepsin/protease activity was significantly higher in fish fed fish protein‐based diets compared with fish fed soy protein‐based diets. The lipase activity in fish fed the SPI‐based diet was the highest among the dietary treatments. These results indicate that P. olivaceus can effectively digest the protein from FPC and SPI (but not SPC) as well as FM. The low protein digestibility and amino acid availability of the SPC‐based diet may be related to the non‐protein compounds present in SPC, whereas the low‐lipid digestibility of soy protein‐based diets may contribute to the undigested soy protein fractions and/or the alcohol‐soluble components.     

Apparent digestibility of selected feed ingredients in diets for juvenile hybrid tilapia,Oreochromis niloticus×Oreochromis aureus

The apparent digestibility coefficients (ADCs) of dry matter, crude protein, crude lipid, ash, phosphorus, gross energy and amino acids of 10 selected ingredients for juvenile hybrid tilapia (7.05 ± 0.09 g) were determined using 0.5% Cr₂O₃ as an inert indicator. The feed ingredients tested in this study were corn gluten meal (CGM), corn byproduct, corn germ meal (CG), soybean meal (SBM), fermented soybean meal (FSM), soy protein concentrate (SPC), soy protein isolate, malt sprouts (MS), fish meal (FM) and earthworm meal (EM). The test diets were prepared by incorporation of 30% test ingredients into the reference diet. Reference and test diets were fed to the fish and the faecal samples were collected using a faecal collection column attached to the fish‐rearing tanks. The ADCs for dry matter, crude protein, crude lipid, ash, phosphorus and gross energy were 41.7–98.9%, 90.6–99.6%, 73.1–98.8%, 34.1–98.6%, 49.5–99.6% and 45.4–99.7% respectively. Soy protein isolate, FM and EM had higher dry matter, crude protein and gross energy ADCs. Corn byproduct and EM had higher crude lipid ADCs, and CG and EM had higher phosphorus ADCs. Corn germ meal had the highest ash ADC, while CGM had the highest value for gross energy. The lowest dry matter, crude protein, lipid and gross energy ADCs occurred in MS, while the lowest ash and phosphorus ADCs occurred in SPC. The amino acid ADCs ranged from 83.3% to 100%, exhibiting a positive correlation with crude protein digestibility for a given test ingredient. The feed ingredient digestibility of this study may provide useful information about nutrient and energy utilization to facilitate formulation of least‐cost practical diets for hybrid tilapia.     

Evaluation of apparent digestibility coefficients of individual feed ingredients in spotted rose snapper Lutjanus guttatus (Steindachner, 1869)

Apparent digestibility coefficients (ADCs) for dry matter, crude protein, energy and essential amino acids for five commonly used feed ingredients were determined for juvenile spotted rose snapper Lutjanus guttatus (average body weight 90.6 g). ADCs were determined using the stripping technique to collect faeces after fish were fed a reference diet and test diets composed of 700 g kg^?1 reference diet and 300 g kg^?1 test ingredient. Chromic oxide (Cr₂O₃) was used as an inert indicator. Ingredients tested included sardine fishmeal (FM), canola meal (CM), tuna by‐products meal (TBM), poultry by‐product meal pet grade (PBM‐PG) and solvent‐extracted soybean meal (SBM). In general, all ingredients showed high digestibility values for all essential amino acids, although differences were detected among ingredients. ADC values for dry matter, protein and energy ranged 77.0–80.4%, 84.3–82.5% and 89–88.8%, respectively, for marine ingredient and land‐based animal protein sources, and 75.0–74.2%, 81.5–80.9% and 87.4–86.8%, respectively, for the plant‐based protein source. SBM, TBM and PBM‐PG should be further evaluated in feeding trials as partial FM replacements in rose snapper L. guttatus diets. Knowledge of ADC values for these ingredients will allow feed producers to develop nutritionally balanced, low‐cost feed formulations for this species.     

Effects of feed ingredients on nutrient digestibility,nitrogen/energy balance and morphology changes in the intestine of Nile tilapia (Oreochromis niloticus)

The present study assessed the effect of different feed ingredients on nutrient apparent digestibility coefficients (ADC), nitrogen/energy balance and morphology changes in the intestine of Nile tilapia; using a control diet and six test diets, in which the following six ingredients were included at 30%: hydrolysed feather meal (HFM), soybean meal (SBM), rice bran (RB), rapeseed meal (RM), sunflower meal (SFM) and dried distillers grains with solubles (DDGS). The proximal, middle and distal intestine was processed for quantitative histology counting the number of goblet cells (GC), and measuring the thickness of lamina propria (LP) and submucosa (SM). The study showed that the ADC of protein in raw materials were highest in SBM (92.2%), followed by SFM (90.2%), DDGS (89.2%), RM (87.8%), HFM (86.9%) and RB (84.0%). The nutrient ADCs had no correlation with intestinal morphology changes. Only the SBM diet caused noticeable changes in intestinal morphology such as an increase the thickness of SM and LP and the number of GC. The diet composition, however, altered the protein efficiency and the maintenance energy requirement. Protein retention efficiency was the lowest in fish fed HFM and the highest in RB. The highest maintenance energy requirements were observed in HFM and SBM treatments.     

Apparent digestibility coefficients of selected feed ingredients for juvenile hybrid tilapia,Oreochromis niloticus×Oreochromis aureus

The apparent digestibility coefficients (ADCs) of dry matter, crude protein, crude lipid, gross energy, phosphorus and amino acids in local fish meal (LFM), Peruvian fish meal (PFM), poultry by‐product meal (PMM), meat and bone meal (MBM), tilapia by‐product meal (TM), fermented soybean meal (FSBM), soybean meal (SBM), peanut meal, canola meal (CM), cottonseed meal (CSM) and de‐gossypoled cottonseed meal were determined for juvenile hybrid tilapia (7.18 ± 0.2 g, mean ± SD). A reference diet (RF) and test diets (consisting of 70% RF and 30% of the feedstuff) were used with 0.5% chromic oxide as an external digestibility marker. The juvenile hybrid tilapias were stocked in 500‐L fibreglass tanks at a density of 20 fish per tank. Faeces were collected from triplicate groups of fish using a faecal collection column attached to the fish‐rearing tank. The results indicated that the ADCs of dry matter for juvenile hybrid tilapia ranged 71.88–89.53% for animal products and 65.89–79.98% for plant products. For crude protein, apparent digestibility coefficients of protein (ADCp) exceeding 90% were observed for FSBM, SBM and PFM, and ADCp of MBM was the lowest among all the treatments. Apparent digestibility coefficients of lipid in all the treatments were above 90%; the results indicate that lipids from both animal and plant sources were well digested by hybrid tilapia. The ADCs of phosphorus of animal and plant feedstuffs ranged between 58.04–74.44% and 52.65–64.23% respectively. The lowest ADC of phosphorus was observed in CSM among plant ingredients and in MBM among animal ingredients. The ADCs of energy were similar to those of dry matter and protein; the highest and lowest ADCs of energy were found in PFM and CM respectively. In general, the amino acid availability coefficients tended to reflect the ADCp among highly digestible ingredients. For the animal products, the availabilities of amino acids in PFM, LFM and PMM were generally higher than that in TM and MBM; among all the plant products, the availabilities of amino acids in FSBM and SBM were higher than in CM. These results indicated that juvenile hybrid tilapia is able to utilize different feedstuffs efficiently.     

Development of plant‐based diets and the evaluation of dietary attractants for juvenile Florida pompano,Trachinotus carolinus L.

Sustainable and profitable commercial aquaculture production of marine fish species is dependent on the development of sustainable protein sources as substitutes for expensive animal meals such as fishmeal (FM). Previous Florida pompano Trachinotus carolinus studies have indicated that poultry by‐product meal (PBM) and meat and bone meal can be used to produce a FM‐free diet if suitable levels of nutrients (such as taurine) are included in the diets. In this study, we attempted to develop an all‐plant protein diet by removing the animal proteins in practical diets for pompano by substituting back select ingredients. A series of eight FM‐free diets were formulated, four systematically replaced soybean meal (SBM) with soy protein concentrate (SPC) and four replaced PBM with SPC. Based on the results, there is no clear disadvantage to the use of SPC as a replacement for SBM. However, the complete removal of PBM resulted in reduced performance. Two additional growth trials were conducted to supplement additional amino acids including glycine, valine and histidine, a proprietary chemical attractant mix, fish protein concentrate and squid hydrolysate to improve the growth of pompano when fed all‐plant protein diets. The only improvement in performance occurred with the squid hydrolysate. These results demonstrate that using soybean meal, soy protein concentrate and corn gluten meal as the primary protein sources, a plant‐based feed formulation can be developed, but the removal of all animal proteins is not yet feasible.     

Apparent digestibility coefficients of selected feed ingredients for dourado Salminus brasiliensis

The excellence of its flesh and fast growth makes the dourado, Salminus brasiliensis , a carnivorous fish native to the Prata basin, a potential candidate for intensive fish farming. This study evaluated the apparent digestibility coefficients (ADC) of energy and nutrients of animal and plant protein sources for the carnivorous Characin dourado S. brasiliensis . Fish (19.5 ± 5.0 g) were stocked in plastic cages (80-L) and fed pelleted test diets containing 30% of the test ingredient [fish meal (FM), poultry by-product meal (PBM), soybean meal (SBM), and corn gluten meal (CGM) plus 70% of a reference diet (481.4 g kg⁻¹ of crude protein and 18.63 kJ of gross energy per gram]. After the last daily meal, cages were transferred to cylindrical, conical-bottomed aquarium (200-L) where faeces were collected by sedimentation in a refrigerated container. Except for ADC of protein and energy, all other ADC of nutrients showed significant differences ( P  < 0.01). ADC values were: 94.3%, 91.3%, 93.1%, and 93.5% for crude protein; 91.0%, 90.3%, 87.8%, and 88.8% for gross energy; 92.1%, 84.5%, 80.6%, and 79.3% for ash; 83.9%, 80.3%, 84.3%, and 84.6% for dry matter; 97.4%, 96.7%, 93.3%, and 91.5% for lipid for FM, PBM, SBM, and CGM, respectively. The average amino acid ADC was: 93.6%, 90.0%, 92.1%, and 92.5% of FM, PBM, SBM, and CGM, respectively. All test ingredients were efficiently used and can partially replace FM in diets for carnivorous dourado.     

Digestibility Characteristics of Selected Feed Ingredients for Developing Bespoke Diets for Nile Tilapia Culture in Europe and North America

The apparent digestibility coefficients of dry matter (ADC DM), protein (ADCp), essential amino acids (ADC EAA), and energy (ADCe) for Nile tilapia of a selected range of animal and plant feed ingredients found in Western European and North American markets were determined. The investigation was able to provide useful data and information as a prelude for effective diet formulation for this fish species. A reference diet was used for the basis of assessing hydrolyzed fish protein concentrate (CPSP), full‐fat soybean meal (FFSBM), solvent‐extracted soybean meal (SESBM), maize gluten meal (MGM), poultry meat meal (PMM), hydrolyzed feather meal (HFM), and spray‐dried hemoglobin meal (SDHM) by substitution. For each major commercial test ingredient, the ADC were as follows: for plant proteins – FFSBM (ADCp 86.99% and ADCe 74.84%), SESBM (ADCp 93.46% and ADCe 82.16), and MGM which was also utilized well by Nile tilapia (ADCp 83.03% and ADCe 82.36%); for animal proteins – PMM (ADCp 69.30% and ADCe 73.47%), HFM (ADCp 45.53% and ADCe 49.11%), and SDHM was highly digested (ADCp 85.79% and ADCe 75.96%). The ADC EAA reflected the same trends as ADCp, and these varied from >87% on average for the EEA in fish meal, >88% for CPSP, >84% for FFSBM, >63% for SESBM, >83% for MGM, and only 61% for PMM, >63% for HFM, and >77% for SDHM. Highest ADC were obtained with SDHM and SESBM among the animal and plant by‐products tested, respectively. These are discussed in the context of practical diets for tilapia.     

Apparent protein and energy digestibility of common and alternative feed ingredients by Atlantic cod, Gadus morhua (Linnaeus, 1758)

Studies were conducted with Atlantic cod, Gadus morhua (L.), to determine the apparent digestibility coefficients (ADCs) of protein and energy and the digestible energy (DE) content in feed ingredients widely available in Canada. We also tested the assumption of “independency” used in digestibility studies. The feed ingredients included two fish meals (herring, anchovy), three crustacean by-product meals (whole krill, crab, shrimp), two animal by-product meals (poultry by-product, hydrolyzed feather), six oilseed meals (soybean, soy protein concentrate, soy protein isolate, canola, canola protein concentrate, flaxseed), two pulse meals (white lupin, pea protein concentrate) and two cereal grain meals (corn gluten, wheat gluten). Protein ADCs were high for wheat gluten meal (99.9%), soy protein concentrate (98.6%), soy protein isolate (97.4%), whole krill meal (96.3%), herring meal (93.3%), soybean meal (92.3%), anchovy meal (92.2%), pea protein concentrate (89.8%), white lupin meal (89.7%), crab meal (89.4%), canola protein concentrate (88.8%) and corn gluten meal (86.3%); mid-range for poultry by-product meal (80.2%) and canola meal (76.0%); and low for shrimp meal (66.7%), hydrolyzed feather meal (62.4%) and flaxseed meal (50.2-55.0%). Energy ADC was high for whole krill meal (96.3%), wheat gluten meal (95.4%), soy protein concentrate (94.9%), herring meal (92.8%), soy protein isolate (92.1%), soybean meal (88.1%) and anchovy meal (86.4%); mid-range for canola protein concentrate (83.3%), corn gluten meal (82.7%), crab meal (82.4%), pea protein concentrate (76.7%) and white lupin meal (75.3%); and low for poultry by-product meal (71.0%), canola meal (60.6%), hydrolyzed feather meal (58.9%), shrimp meal (41.4%) and flaxseed meal (21.2-37.4%). From the protein ADC data, results clearly showed that the basal diet and test feed ingredients were digested independently of one another in nearly all cases, the only exceptions being for those diets containing test ingredients of very high (> 99%, wheat gluten) or very low (< 67%, hydrolyzed feather and flaxseed) protein ADCs. In the case of DE, the basal diet and test feed ingredients were digested independently in all test diets without exception.     

Interactive effects of dietary cholesterol and protein sources on growth performance and cholesterol metabolism of Japanese flounder (Paralichthys olivaceus)

A feeding trial was conducted to compare the effects of supplemental cholesterol in fish meal (FM), fish protein concentrate (FPC), soy protein isolate (SPI) and soy protein concentrate (SPC)‐based diets on growth performance and plasma lipoprotein levels of Japanese flounder (Paralichthys olivaceus). Eight isonitrogenous and isocaloric diets including FM, FPC, SPI or SPC as sole protein source with or without supplementation with 10 g cholesterol kg^?1 diet were fed to juvenile fish for 8 weeks. Dietary cholesterol supplementation significantly increased the feed intake and specific growth rate in fish fed SPI‐based diets, but decreased those in fish fed FPC‐based diets. In addition, cholesterol supplementation significantly increased the level of cholesterol and ratio of low‐density lipoprotein cholesterol to high‐density lipoprotein cholesterol in plasma of fish fed fish protein‐based diets, whereas no effects were observed in fish fed soy protein‐based diets. The hepatic lipid content of fish fed FPC‐, SPI‐ or SPC‐based diets were significantly increased by supplemental cholesterol, but no influence was observed in fish fed FM‐based diets. These results suggested that dietary protein source modify the growth‐stimulating action of cholesterol; cholesterol supplementation may increase the arteriosclerotic lesion in fish fed fish protein‐based diets and the incidence of fatty liver in fish fed soy protein‐based diets.