Requirement of Sodium to Molted Laying Hens

ABSTRACT The objective of this study was to determine the ideal requirement of sodium to molted laying hens. The experimental period lasted 105 days, divided into five periods of 21 days. Hisex White laying hens 150 with 84 weeks-of-age were used. The experimental design was completely randomized in a factorial scheme (5x3) with treatments constituted by five levels of sodium (0.10, 0.15, 0.20, 0.25, and 0.30%) in the diets, and three postmolt stages (early = 21 days, medium = 63 days, and final = 105 days). Performance and egg quality results were evaluated by Tukey test at 5%. Eggshell resistance and weight gain results were evaluated by polynomial regression at 5%. Except the yolk height, all performance and egg quality variables were affected (p<0.05) by the sodium levels and the hens’ age postmolt. The level of 0.15% of sodium in diets to postmolt laying hens provided better performance and egg quality, especially in the eggshell. Higher levels of sodium negatively affected the performance and egg quality. Hens in the early stage of postmolt period presented better performance and egg quality. At long-term, the postmolt hens presented worst results.

摘要 本研究旨在确定换羽后产蛋鸡的理想钠需求量。试验周期共计105天，划分为5个21天的试验阶段。试验选用150只84周龄的海塞克白（Hisex White）产蛋鸡。试验采用完全随机因子设计（5×3），处理组包含日粮5个钠添加水平（0.10%、0.15%、0.20%、0.25%与0.30%）以及3个换羽后阶段（早期=21天、中期=63天、末期=105天）。采用Tukey检验在5%显著水平下对生产性能与蛋品质指标进行统计分析；蛋壳强度与增重指标则采用5%显著水平下的多项式回归进行分析。除蛋黄高度外，所有生产性能与蛋品质变量均受日粮钠水平与换羽后鸡只日龄的显著影响（p<0.05）。日粮中添加0.15%的钠可使换羽后产蛋鸡获得更优的生产性能与蛋品质，尤以蛋壳品质提升最为显著。更高水平的钠则会对生产性能与蛋品质产生负面影响。换羽早期的产蛋鸡表现出更优的生产性能与蛋品质，而长期换羽后的鸡只各项指标结果最差。