团头鲂（Megalobramaamblycocephala Yih）对12种饲料原料消化率和…

本实验以三氧化二铬为指示剂测定了一冬龄团头鲂对１２种饲料原料的干物质，粗蛋白质，粗脂肪，无氮浸出物，总磷和总能量的表现消化率，首次报道了总磷消化率和可消化能。从表现消化率和可消化能的角度评价了１２种饲料原料的营养价值，为开发适用于团头鲂的人工配合饲料提供了科学依据。     

团头鲂对7种饲料的蛋白质、氨基酸及磷的表观消化率

本实验以0.5%的三氧化二铬(Cr2O3)为指示剂,研究分别以鱼粉、肉骨粉、豆粕、花生粕、棉粕、酒精糟及其残液干燥物(DDGS)和菜粕作为蛋白饲料,将这7种饲料原料与基础日粮按照3:7的比例组成实验日粮,观测团头鲂(Megalalobrama amblycephala Yih)对这7种饲料的干物质、粗蛋白、氨基酸及总磷的表观消化率.实验鱼初始体质量为(296.54±1.71)g,分别投喂相应的实验饲料5周后采用自排法收集粪便.结果表明,7种饲料原料的干物质、蛋白质、总氨基酸以及总磷的表观消化率的范围分别为53.65%～77.48%、78.66%～93.63%、80.12%～94.83%、3.21%～48.02%.其中粗蛋白及总氨基酸的表观消化率均以菜粕最高;花生粕、豆粕与鱼粉相接近;肉骨粉最低.磷的表观消化率以DDGS最高,菜粕和肉骨粉最低,其他4种原料的磷的表观消化率范围为11.81%～29.10%.由此可见,菜粕、豆粕、花生粕可作为团头鲂优质的植物蛋白源,在实际生产配方中可部分替代鱼粉.DDGS蛋白消化率高于肉骨粉,且磷的表观消化率较高,也可作为一种优质的鱼用饲料原料.     

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。     

两种水温条件下团头鲂对7种蛋白源饲料表观消化率的比较

采用由30%待测蛋白源饲料原料和70%基础饲料组成的试验饲料,以三氧化二钇(Y_2O_3)作外源指示剂,添加量为0.05%,以平均体重(34.38±1.06)g的团头鲂(Megalobrama amblycephala)幼鱼作研究对象,在30℃和25℃两种水温条件下比较研究其对鱼粉(FM)、豆粕(SBM)、菜粕(RSM)、棉粕(CSM)、酵母浸粉(YEF)、肉骨粉(MBM)和花生粕(PNM)7种蛋白源饲料原料的干物质(DM)、粗蛋白(CP)、总能(GE)、总氨基酸(TAA)及必需氨基酸(EAA)的表观消化率。结果显示:水温30℃时,酵母浸粉的干物质、总能、粗蛋白和必需氨基酸的表观消化率最高;水温25℃时,原料干物质和总能的表观消化率最高的为鱼粉,粗蛋白、必需氨基酸和总氨基酸的表观消化率最高的为豆粕。在两个水温下,原料干物质、粗蛋白、总氨基酸和必需氨基酸的表观消化率最低的均是肉骨粉,总能的表观消化率最低的是棉粕。在30℃时团头鲂对蛋白源饲料原料各营养成分的表观消化率高于25℃时,且酵母浸粉在两个水温下各营养成分的消化率差异显著(P0.05)。在30℃时,酵母浸粉的各养分表观消化率较高,但其氨基酸平衡性较差,需适量添加蛋氨酸,满足团头鲂对氨基酸的需求;在25℃时,豆粕和鱼粉各养分表观消化率较高,可作为团头鲂饲料的优质蛋白源饲料原料。肉骨粉在两个水温下均表现出最低表观消化率,需搭配其他饲料适量使用。     

用两种粪便收集方法测定草鱼对九种饲料原料的表观消化率

在(21.5±1.0)℃水温下,以Cr2O3为指示物采用自排法和挤压法分别收集平均体重为65 g草鱼的粪便,测定草鱼对棉籽粕、花生粕、双低菜籽粕、秘鲁鱼粉、菜籽粕、小麦次粉、米糠、大豆粕和肉骨粉9种饲料原料主要营养成分的表观消化率。试验饲料以70%基础饲料和30%的待测饲料原料组成。结果表明:(1)草鱼对肉骨粉、秘鲁鱼粉、棉籽粕、大豆粕的干物质表观消化率较高,分别为60.69%、59.07%、61.08%、57.99%;(2)用自排法和挤压法测定草鱼对饲料原料的表观消化率时,干物质表观消化率有差异,而饲料原料粗蛋白质表观消化率基本保持一致;(3)草鱼对各种饲料原料的蛋白质表观消化率与氨基酸表观消化率的趋势基本一致。     

大口黑鲈对四种蛋白质饲料原料的表观消化率研究

为大口黑鲈的营养研究和配合饲料研制提供理论依据，试验以Cr2O3为消化指示物，测定了大口黑鲈（Micropterus salmoides）对进口白鱼粉、国产鱼粉、普通豆粕和发酵豆粕的干物质、蛋白质和脂肪的表观消化率。试验饲料由基础饲料和试验原料以70：30的质量比混合挤压成软颗粒饲料。试验结果表明，大口黑鲈对动物性蛋白白鱼粉和红鱼粉的干物质表观消化率分别为78．56％和9．12％，高于植物性蛋白普通豆粕的68．28％和发酵豆粕的72．19％，而发酵豆粕的干物质表观消化率比普通豆粕要高一些。大口黑鲈对4种饲料原料的蛋白质表观消化率在80．21％～85．55％，对4种饲料原料的脂肪表观消化率为81．18％～91．06％。大口黑鲈可以很好地利用4种饲料原料中的蛋白质和脂肪。     

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。     

13种饲料原料蛋白质对尼罗罗非鱼的营养价值

以Ｃｒ２Ｏ３为指示物，以７０％基础饲料和３０％的待测饲料原料组织成试验饲料，测定尼罗非鱼对１３种饲料对料的蛋白质和必需氨基酸的表观消化率。以有效必需氨基酸含量计算了饲料原料中蛋白质的必需氨基酸指数，并和鱼体必需氨基酸含量进行比较，评价了饲料原料蛋白质对尼罗罗非鱼的营养价值。结果表明，氨基酸总量消化率和蛋白质消化率接近；秘鲁鱼粉、大豆粕和玉米蛋白质的有效必需氨基酸指数均在７０％以上，其营养价值分别是     

草鱼对27种饲料原料中氨基酸的表观消化率

本试验以0.5％Cr2O3为指示物,按照“70％基础饲料 30％试验原料“的饲料配制方法,在可控条件的室内循环养殖系统中用2龄草鱼种（体重150-200g）对常用的饲料原料的氨基酸表观消化率进行测定。试验选用了进口鱼粉、国产鱼粉、蟹粉、肉粉、肠衣粉、酵母、菜饼、黄菜粕、菜粕、双低菜籽粕、豆粕、膨化大豆、芝麻饼、棉粕、玉米胚芽粕、玉米蛋白粉和酒糟粉共17种商品蛋白质饲料原料,玉米、麦麸、次粉、米糠、标粉、小麦、大麦、玉米糟、稻谷、药渣共10种能量饲料原料,得到了每种原料的16种氨基酸的表观消化率。表观消化率主要规律表现为：草鱼对原料蛋白质消化率高时对氨基酸的总消化率也高,如对鱼粉、豆粕的消化率高;对玉米类原料如玉米蛋白粉、玉米渣、玉米的氨基酸消化率较低,而对小麦类原料如小麦粉、麦麸、次粉等的消化率相对较高;在植物饼粕类中,草鱼对豆粕和菜粕的消化率较高,而对棉粕的消化率则相对较低;对同种原料的16种不同的氨基酸的表观消化率也有很大的差异,这种差异的规律性较差。     

翘嘴红鲌鱼种对八种蛋白质饲料原料的消化率

本试验按照“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 ,测定了翘嘴红鱼种 (体重 12 5± 1 5 g )对鱼粉、血粉、蚕蛹粉、酵母、豆粕、花生粕、菜籽粕、棉籽粕等 8种常用的饲料原料的干物质、蛋白质、粗脂肪的表观消化率。结果表明 :翘嘴红对 8种原料的干物质表观消化率和蛋白质表观消化率分别为 4 3 4 3%～ 86 90 %和 6 6 34%～ 95 18% ,对 5种原料的脂肪表观消化率为 6 6 6 9%～ 94 16 %。     

Apparent digestibility of various feedstuffs for bluntnose black bream Megalobrama amblycephala Yih

The apparent digestibility of 66 different feedstuffs by the bluntnose black bream Megalobrama amblycephala Yih was determined in digestibility trials in a recirculation aquaculture system. The ingredients consisted of 26 distinct energy feedstuffs, 18 nonanimal protein feedstuffs and 22 animal protein feedstuffs. In each of three trials, a reference diet was mixed with various test ingredients in a 70 : 30 ratio; reference and test diets were fed to the fish, and faecal samples were collected using a hand‐held screen system. Energy availability for the 26 energy feedstuffs varied between ?23.0% (silkworm manure) and 89.5% (millet grain), protein digestibility for the 18 nonanimal protein ingredients varied from 58.0% (pea protein meal) to 98.1% (soybean meal), and protein digestibility for the 22 animal protein feedstuffs varied between ?5.7% (feather meal) and 99.1% (fermented dried blood meal). The average protein digestibility of 85.9% for the nonanimal protein feedstuffs was significantly higher than that for the animal feedstuffs (P < 0.05), partly validating the assumption that herbivorous bluntnose black bream would digest proteinic nutrients in nonanimal feedstuffs better than in animal ingredients under intensive aquaculture. Finally, the energy availability of nonanimal protein feedstuffs was significantly lower than that of animal feedstuffs (P < 0.05).     

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.     

Apparent digestibility coefficients of selected protein feed ingredients for loach Misgurnus anguillicaudatus

Apparent digestibility coefficients of dry matter, crude protein, lipid and energy, and amino acids availability in white fish meal, brown fish meal, meat meal, fermented soybean meal, soybean meal and rapeseed meal were determined for loach (Misgurnus anguillicaudatus) (12.05 ± 0.21 g), using a reference diet with 5 g kg^?1 chromic oxide and test diets that contained 700 g kg^?1 reference diet, by weight, and 300 g kg^?1 of the test feed ingredients. The juvenile loach was held in 300‐l tanks at a density of 30 fish per tank. White fish meal, brown fish meal, meat meal and fermented soybean meal had highest apparent digestibility coefficients (ADCs) of dry matter, crude protein and gross energy among ingredients tested, ranged from 50.4% to 60.9% for dry matter, from 64.6% to 88.4% for crude protein and from 57.9% to 79.0% for gross energy. The apparent digestibility coefficients of dry matter ranged from 61.0% to 66.9% for animal products and 50.4% to 60.7% for plant products. For crude protein, apparent digestibility coefficients of protein exceeding 80% were observed for white fish meal, brown fish meal, meat meal and fermented soybean meal, and the apparent digestibility coefficients of protein in rapeseed meal were the lowest among all the treatments. Lipids from both animal and plant feedstuffs were poorly digested by loach, ranging from 64.0% to 77.6%. The apparent digestibility coefficients of energy were similar to those of dry matter and protein, and the highest and lowest ADCs of energy were found in WFM and RM, respectively. The loach used dietary phosphorus from the animal feedstuffs more efficiently than from plant feedstuffs (soybean meal and rapeseed meal), with ADC‐values ranging from 42.3% to 53.1% and from 25.1% to 32.7%, respectively. For the animal products, the availabilities of amino acids in white fish meal and brown fish meal were higher than that in meat meal, expect for Met, Asp, Pro, Gly, and Cys. Among all the plant products, the availabilities of amino acids in fermented soybean meal were higher than in soybean meal and rapeseed meal, and thus had a greater potential to be used as a dietary replacement of fish meal in loach diets.     

Apparent Digestible Energy Coefficients and Associative Effects in Practical Diets for Red Swamp Crayfish

Adult red swamp crayfish ( Procambarus clarkii ) were held in fecal collection chambers and fed common feedstuffs in two different types of diets, as the sole feedstuff and as a 30% substitution in a reference diet. Feedstuffs tested were soybean meal, peanut meal, wheat shorts, cooked corn, menhaden fish meal, and shrimp-head meal. Feed consumption, apparent digestible dry matter, and energy coefficients were determined for feedstuffs when fed in both diets. Addition of menhaden fish meal, shrimp-head meal, and peanut meal in the reference diet resulted in decreased consumption, and menhaden fish meal was poorly digested when incorporated at 30% in the reference diet. Apparent dry matter and energy digestion coefficients Indicated that plant feedstuffs have greater potential as ingredients in crayfish diets than feedstuffs of animal origin. Differences in consumption and digestibility between the two types of diet were observed. Therefore, it appears that the associative effects of additions of feedstuffs in diets should be considered when formulating crayfish feeds.     

Apparent digestibility of selected feed ingredients for white shrimp Litopenaeus vannamei,Boone

Apparent digestibility coefficients of dry matter (DM), crude protein, crude lipid, gross energy, phosphorus and amino acids in Peruvian fish meal (FM), fermented soybean meal, extruded soybean meal, soybean meal, peanut meal, wheat gluten meal, corn gluten meal, shrimp byproduct meal, meat and bone meal (MBM), poultry meat meal and plasma protein meal (PPM) were determined for white shrimp (Litopenaeus vannamei). A reference diet (RF) and test diets (consisting of 70% RF diet and 30% of the feedstuff) were used with 0.5% chromic oxide as an external indicator. A total of 1440 shrimp (initial mean body weight 1.05 ± 0.01 g) were randomly stocked into thirty‐six 500‐L fibreglass tanks with 40 shrimp per tank and three tanks per diet. Faeces were collected from triplicate groups of shrimp by a faecal collection vessel attached to the shrimp‐rearing tank. The shrimp were fed to apparent satiation four times a day and the feeding experiment lasted for 6 weeks. Statistics indicate that apparent DM digestibilities for white shrimp (L. vannamei) were the highest for FM, ranged 52.83–71.23% for other animal products and 69.98–77.10% for plant products. The protein and lipid from plant and animal sources were well digested by white shrimp. Apparent protein and lipid digestibility were in the range 87.89–93.18% and 91.57–95.28%, respectively, in plant products, and 75.00–92.34% and 83.72–92.79%, respectively, for animal products. The white shrimp demonstrated a high capacity to utilize phosphorus in the ingredients. The apparent phosphorus digestibility ranges of animal feedstuffs and plant feedstuffs were 58.90–71.61% and 75.77–82.30% respectively. Amino acid availability reflected protein digestibility, except that in MBM, for which the availability of some amino acid was lower, possibly due to protein damage during processing. Digestibility information could promote the use of ingredient substitution in least‐cost formulated diets for white shrimp.     

Apparent Digestible Energy and Nutrient Digestibility Coefficients of Diet Ingredients for Pacu Piaractus brachypomus

The digestible energy and apparent nutrient digestibility coefficients of common diet ingredients were determined for pacu Piaractus brachypomus (370.21 ± 17.56 g). Fish were fed with pelleted practical diets to apparent satiation and the feces were collected by siphoning. The digestibility value for each ingredient was determined by comparison of the digestibility of a test diet with a reference diet (24.5% crude protein and 1% chromic oxide). The digestible energy values of soybean meal (SBM), fish meal (FM), corn (CN), and wheat bran (WB) were 2382. 3826, 3353, and 1784 kcal/kg, respectively. The apparent dry matter digestibility coefficients were 83.72, 90.14, 89.13, and 82.05% for SBM, FM, CN, and WB, respectively. The apparent crude protein digestibility coefficients were 75.88, 90.49, 85.06, and 61.62% for SBM. FM, CN, and WB, respectively. The apparent lipid digestibility coefficients were 63.03, 77.00, 83.01, and 82.45% for SBM, FM, CN, and WB, respectively. The digestibility of protein, lipid, and energy from SBM were somewhat low compared to values for other warmwater omnivorous fishes, but similar to values reported for pacu-caranha P. mesopotamicus. Otherwise, the nutrient and energy availability of the ingredients to P. brachypomus was similar to that of other fish. This information will be useful in formulating nutritious, economical diets for pacus.     

Digestibility of Alternative Protein‐Rich Feedstuffs for Channel Catfish,Ictalurus punctatus

Apparent digestibility coefficients (ADCs) of amino acids, crude protein, gross energy, and dry matter of canola meal, corn gluten feed, fish offal meal, shrimp and fish offal meal, poultry by‐product meal, and hydrolyzed feather meal were determined for channel catfish, Ictalurus punctatus. Experimental diets contained 30% test ingredient, 69.5% casein‐based reference diet, and 0.5% chromic oxide. Groups of 20 fish (102.45 g) were fed the experimental diets twice a day at 3.5% body weight. Fecal samples were collected in triplicate daily at 0000 h and 0600 h after settlement into collection devices. Shrimp and fish offal meal and corn gluten feed presented significantly lower (P < 0.05) ADC for dry matter (59.5 and 39.3%) suggesting their low value as feedstuffs for catfish feeds. Although ADC values for crude protein were above 80% for all the test ingredients, amino acid digestibility varied significantly, except for histidine whose ADC remained constant regardless of the protein source. Lysine was the first limiting amino acid in most of the test ingredients, except in fish offal meal and poultry by‐product meal. Among the protein sources tested, only fish offal meal and poultry by‐product meal met channel catfish amino acid requirements for a 28% digestible protein grow‐out diet.     

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.     

Apparent digestibility of Asian carp‐ and common carp‐derived fish meals in feeds for hybrid striped bass Morone saxatilis ♀ × M. chrysops ♂ and rainbow trout Oncorhynchus mykiss

Apparent digestibility coefficients (ADCs) of nutrients (crude protein, amino acids, crude lipid, fatty acids, and minerals) were determined for fish meals derived from menhaden, Asian carp (combination of silver and bighead carps), and common carp in feeds for hybrid striped bass and rainbow trout. Extruded test diets were formulated to contain a 70 : 30 mixture of reference diet and test ingredient with yttrium oxide (1 g kg^?1) serving as the inert marker. Diets were randomly assigned to triplicate tanks and fish were fed once per day at 2% body weight. Fecal samples were collected by manual stripping. The ADCs were calculated according to standard procedures. The composition and digestibility of Asian carp and common carp meals was broadly similar to menhaden meal. Protein digestibility ranged from 86.5% (Asian carp meal) to 93.1% (common carp meal). Lipid was highly digestible with ADCs >100% for all ingredients. Although the Asian carp meal was less digestible than the other two fish meals, it was still a highly digestible ingredient. Our data suggest that fish meals derived from Asian or common carp would be valuable feedstuffs in diets for hybrid striped bass, rainbow trout, and possibly other cultured fishes.