Black soldier fly larvae (BSFL) are an alternative protein source for animals, including dogs and cats. Dietary calcium source is an essential nutrient for BSFL development in the pupal stage. Calcium carbonate (CaCO3) and calcium chloride (CaCl2) are common calcium sources but differ in solubility, acid-binding capacity, and calcium concentration. A high calcium concentration in BSFL may affect how well nitrogen and amino acids (AA) are digested by animals consuming them, thereby affecting feed conversion efficiency. Our objective was to determine the effects of dietary calcium form and concentration on nutrient composition, AA digestibility, and digestible indispensable amino acid score (DIAAS)-like values of BSFL intended for use in animal feeds using the precision-fed cecectomized rooster assay. All BSFL tested in this study were harvested at 18 d after hatch. Industry standard rearing conditions were maintained and a commercial layer ration was fed to all BSFL until 11 d post-hatch. From day 11 to 18, BSFL were fed a combination of distiller’s dried grains with solubles from a distillery, bakery byproduct meal, and varied calcium sources. All BSFL diets contained 0.2% calcium in the basal diet plus additional calcium in the following amounts and forms: BSFLA: 1.2% CaCl2, BSFLB: 1.2% CaCO3, BSFLC: 0.75% CaCO3, and BSFLD: 0.6% CaCO3 + 0.6% CaCl2. On day 18, BSFL were washed and frozen. Prior to the rooster assay, BSFL were lyophilized and ground. In total, 16 cecectomized roosters (4 roosters per substrate) were randomly assigned to test substrates. After 24 h of feed withdrawal, roosters were tube-fed 20 g of test substrates. Following crop intubation, excreta were collected for 48 h. Endogenous corrections for AA were made using five additional cecectomized roosters. All data were analyzed using a completely randomized design and the GLM procedure of SAS 9.4. Nutrient and AA digestibilities were not different among substrates. DIAAS-like values were calculated to determine protein quality according to the Association of American Feed Control Officials nutrient profiles and National Research Council recommended allowances for dogs and cats. Although AA digestibilities did not differ, those containing CaCO3 generally had higher DIAAS-like reference values than the diet containing CaCl2 alone (BSFLA). Aromatic AA (Phe + Tyr) and sulfur AA (Met + Cys) were often first-limiting AA. Our results suggest that calcium sources fed to BSFL did not affect AA digestibility and protein quality.

中文翻译：

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使用精确饲喂盲肠切除公鸡试验，饲喂不同形式和浓度的钙的黑水虻幼虫的氨基酸消化率和可消化必需氨基酸评分值


黑水虻幼虫 (BSFL) 是动物（包括狗和猫）的替代蛋白质来源。膳食钙源是蛹期 BSFL 发育的必需营养素。碳酸钙 (CaCO3) 和氯化钙 (CaCl2) 是常见的钙源，但溶解度、酸结合能力和钙浓度不同。 BSFL 中的高钙浓度可能会影响动物对氮和氨基酸 (AA) 的消化程度，从而影响饲料转化效率。我们的目的是通过精确饲喂盲肠切除公鸡测定，确定膳食钙形式和浓度对动物饲料中 BSFL 的营养成分、AA 消化率和可消化必需氨基酸评分 (DIAAS) 样值的影响。本研究中测试的所有 BSFL 均在孵化后 18 天收获。维持行业标准饲养条件，并向所有 BSFL 饲喂商业蛋鸡日粮，直至孵化后 11 天。从第 11 天到第 18 天，BSFL 饲喂干酒糟与来自酿酒厂的可溶物、烘焙副产品粉和各种钙源的组合。所有 BSFL 日粮均在基础日粮中含有 0.2% 钙，另外还添加了以下数量和形式的钙：BSFLA：1.2% CaCl2、BSFLB：1.2% CaCO3、BSFLC：0.75% CaCO3 和 BSFLD：0.6% CaCO3 + 0.6% CaCl2。第18天，洗涤并冷冻BSFL。在进行公鸡测定之前，将 BSFL 冻干并研磨。总共 16 只盲肠切除的公鸡（每个基质 4 只公鸡）被随机分配到测试基质。停料 24 小时后，给公鸡饲喂 20 克测试底物。作物插管后，收集排泄物 48 小时。 使用另外五只盲肠切除的公鸡对 AA 进行内源性校正。所有数据均使用完全随机设计和 SAS 9.4 的 GLM 程序进行分析。不同底物的养分和氨基酸消化率没有差异。根据美国饲料控制官员协会的营养概况和国家研究委员会建议的狗和猫的摄入量，计算类似 DIAAS 的值来确定蛋白质质量。尽管 AA 消化率没有差异，但含有 CaCO3 的饮食通常比仅含有 CaCl2 的饮食 (BSFLA) 具有更高的 DIAAS 样参考值。芳香族AA（Phe + Tyr）和硫AA（Met + Cys）通常是第一限制性AA。我们的结果表明，饲喂 BSFL 的钙源不会影响 AA 消化率和蛋白质质量。