Terrazas Martín, Civera Roberto, Ibarra Lilia, Goytortúa Ernesto
Laboratorio de Nutrición Acuícola, Centro de Investigaciones Biológicas del Noroeste (CIBNOR), Calle Mar Bermejo # 195, Col. Playa Palo de Santa Rita. La Paz, B. C. S., Código Postal 23090, México.
Rev Biol Trop. 2010 Dec;58(4):1561-76.
Protein quality mainly depends on the essential amino acid (EAA) profile, but also on its bioavailability, because EAA digestibility is generally lower than the analyzed amounts. This information is needed in the aquaculture industry for aquafeed formulation. For this purpose, the apparent digestibility coefficients of dry matter, protein, and essential amino acids of eight feedstuffs of terrestrial origin were determined for the juvenile whiteleg shrimp Litopenaeus vannamei (15-19 g), using 1% chromic oxide as an inert marker. A reference diet was formulated and produced in the laboratory. Eight experimental diets were prepared each with 30% of one of the experimental ingredients added to the reference diet: casein, porcine byproduct meal poultry byproduct meal, corn meal, wheat gluten meal, soybean paste, sorghum meal, and wheat meal. The experiment consisted of a single-factor, completely randomized design with three replicates per treatment. Samples of ingredients, diets and feces were analyzed for nitrogen and amino acids. For amino acid assay, we used reverse-phase high performance liquid chromatography. To avoid partial loss of methionine and cystine, samples of ingredients, diets, and feces were oxidized with performic acid to methionine sulfone and cysteic acid prior to acid hydrolysis. The apparent dry matter and protein digestive utilization coefficients varied from 68% to 109% and from 70% to 103%, respectively. Apparent digestibility of protein for casein, soy paste, wheat meal and wheat gluten were very high (over 90%), corn gluten and poultry byproducts meal showed high protein digestibility (over 80%), but porcine byproducts meal and sorghum meal had low digestibility (76% and 70%, respectively). There was a reasonable, but not total, correspondence between apparent protein digestibility and average essential amino acid digestibility coefficients, except for arginine in corn gluten, phenylalanine and leucine in sorghum meal, phenylalanine in soy paste and lysine in wheat meal and poultry by-product meal. The most digestible feed ingredients for whiteleg shrimp were: wheat gluten, wheat meal and soy paste; poultry byproduct meal and corn gluten were less digestible and the lowest digestibility occurred in porcine byproduct meal and sorghum meal. Feedstuffs exhibited great variability in dry matter, protein and amino acid digestive utilization coefficients, which should be considered when formulating shrimp feeds.
蛋白质质量主要取决于必需氨基酸（EAA）组成，但也取决于其生物利用率，因为EAA的消化率通常低于分析量。水产养殖业在配制水产饲料时需要这些信息。为此，以1%氧化铬作为惰性标记物，测定了凡纳滨对虾幼虾（15-19克）对8种陆生来源饲料原料的干物质、蛋白质和必需氨基酸的表观消化率系数。在实验室配制并生产了一种对照饲料。制备了8种实验饲料，每种饲料将30%的一种实验成分添加到对照饲料中：酪蛋白、猪副产品粉、家禽副产品粉、玉米粉、小麦面筋粉、豆粕、高粱粉和小麦粉。实验采用单因素完全随机设计，每个处理重复3次。对饲料原料、饲料和粪便样本进行氮和氨基酸分析。对于氨基酸分析，我们使用反相高效液相色谱法。为避免蛋氨酸和胱氨酸部分损失，在酸水解前，将饲料原料、饲料和粪便样本用过甲酸氧化为甲砜和磺基丙氨酸。干物质和蛋白质的表观消化利用率系数分别在68%至109%和70%至103%之间。酪蛋白、豆粕、小麦粉和小麦面筋粉的蛋白质表观消化率非常高（超过90%），玉米蛋白粉和家禽副产品粉的蛋白质消化率较高（超过80%），但猪副产品粉和高粱粉的消化率较低（分别为76%和70%）。除了玉米蛋白粉中的精氨酸、高粱粉中的苯丙氨酸和亮氨酸、豆粕中的苯丙氨酸以及小麦粉和家禽副产品粉中的赖氨酸外，蛋白质表观消化率与必需氨基酸平均消化率系数之间存在合理但不完全的对应关系。凡纳滨对虾最易消化的饲料原料是：小麦面筋、小麦粉和豆粕；家禽副产品粉和玉米蛋白粉较难消化，猪副产品粉和高粱粉的消化率最低。饲料原料在干物质、蛋白质和氨基酸消化利用率系数方面表现出很大差异，在配制对虾饲料时应予以考虑。
