ABSTRACT

For reasons of aspired naturalness and cost reduction, vitamin additions should be kept low in organic livestock systems. To define safe lower threshold levels of riboflavin supplementation in organic poultry feeding, 135 hybrid layers were allocated to three dietary treatments supplemented with either 4.5 (R4.5), 3.0 (R3.0) or 1.5 mg (R1.5) GMO-free riboflavin added per kg feed. This resulted in total measured concentration averages of 5.0, 4.5, and 3.1 mg kg⁻¹ feed for R4.5, R3.0 and R1.5, respectively. For 18 weeks, each treatment was replicated in three groups of 15 hens. Feed consumption, laying performance, egg quality, riboflavin concentration in the yolk, and clinical health scores were assessed. Two hens per group (six per treatment) were slaughtered in weeks 11 and 18, respectively, for measurement of pancreas, spleen, liver and heart weights, and determination of liver riboflavin. No treatment effects on feed consumption, body weight, laying performance, egg weights, eggshell strength and yolk colour or plumage and keel bone integrity were observed. No symptoms of lameness or footpad damage were found. The riboflavin concentration in egg yolks in R1.5 was lower than in other treatments. Liver riboflavin concentration increased between week 11 and 18 in all treatments, but it was also lower in R1.5. Based on these results, the addition of 3 mg riboflavin kg⁻¹ feed appeared to be sufficient with respect to the health and performance of laying hens. Supplementation with only 1.5 mg kg⁻¹ resulted in some metabolic signs of deficiency. These results apply only to organic winter diets.

摘要

出于渴望自然和降低成本的原因，有机畜牧系统中的维生素添加量应保​​持在较低水平。为了确定有机家禽饲养中核黄素补充剂的安全较低阈值水平，将 135 个混合蛋鸡分配到三种膳食处理中，辅以 4.5 (R4.5)、3.0 (R3.0) 或 1.5 mg (R1.5) 无转基因每公斤饲料添加核黄素。这导致总测量浓度平均值为 5.0、4.5 和 3.1 mg kg ^-1分别为 R4.5、R3.0 和 R1.5 进料。在 18 周内，每个处理在三组 15 只母鸡中重复。评估了饲料消耗、产蛋性能、鸡蛋质量、蛋黄中的核黄素浓度和临床健康评分。每组 2 只母鸡（每个处理 6 只）分别在第 11 周和第 18 周屠宰，用于测量胰腺、脾脏、肝脏和心脏的重量，并测定肝脏核黄素。没有观察到处理对饲料消耗、体重、产蛋性能、蛋重、蛋壳强度和蛋黄颜色或羽毛和龙骨完整性的影响。没有发现跛足或脚垫损坏的症状。R1.5 中蛋黄中的核黄素浓度低于其他处理。在所有治疗的第 11 周和第 18 周之间，肝脏核黄素浓度增加，但在 R1.5 中也较低。基于这些结果，添加 3 mg 核黄素 kg就蛋鸡的健康和生产性能而言，^{-1饲料似乎就足够了。}仅补充 1.5 mg kg ^-1会导致一些缺乏的代谢迹象。这些结果仅适用于有机冬季饮食。