Antioxidant effect of the guava byproduct in the diet of broilers in the starter phase

ABSTRACT This work aimed to investigate the antioxidant capacity of the guava agroindustrial waste as a functional additive in broiler feed to improve the performance and meat quality of boilers. The experiment was conducted in a completely randomized design, consisting of four treatments and six replicates with 12 birds. Treatments included different levels of guava byproduct in the feed: 0, 0.5, 1.0, and 1.5%. We evaluated the performance of broilers at 7 and 21 days old. At 21 days old, two birds from each experimental unit were euthanized for intestine histologic evaluation (duodenum, jejunum, and ileum) and breast and deboned thigh samples were collected for analyzes of pH, colorimetry (L*, a*, and b*), and thiobarbituric reactive substances (TBARS). The use of guava byproduct in the diet at 7 days old did not affect feed intake and feed conversion of the birds. However, the body weight and weight gain increased linearly with the inclusion of the byproduct. At 21 days old, the guava byproduct did not depress the performance of birds. There was no effect of treatments on villus height, crypt depth, and villus:crypt ratio of the duodenum and jejunum of the birds. The inclusion of guava byproduct resulted in lower crypt depth and linear increase in villus:crypt ratio of the ileum. There was no significant difference in pH and colorimetry of the breast and thigh. With increasing inclusion of byproduct, TBARS value was reduced to 0.72%, indicating greater lipid stability in thigh meat in this inclusion amount. Guava byproduct can be used as an alternative antioxidant additive in broiler feed because it does not depress the productive performance and improves thigh meat quality of boilers.

摘要
本研究旨在探究番石榴农产废弃物作为功能性添加剂应用于肉鸡饲料中的抗氧化能力，以改善肉鸡的生产性能与肉品品质。本实验采用完全随机设计，设置4种处理组，每组6个重复，每个重复包含12只肉鸡。处理组分别在饲料中添加不同水平的番石榴副产物：0、0.5%、1.0%及1.5%。
分别于肉鸡7日龄与21日龄时评估其生产性能。在肉鸡21日龄时，从每个实验单元中选取2只肉鸡实施安乐死，用于肠道组织学评估（采集十二指肠、空肠及回肠样本）；同时采集胸肌与去骨大腿肉样本，用于pH值检测、比色分析（L*、a*、b*值）以及硫代巴比妥酸反应物（thiobarbituric reactive substances, TBARS）测定。
在肉鸡7日龄时，饲料中添加番石榴副产物对其采食量与饲料转化率无显著影响。但肉鸡的体重与体增重随副产物添加水平的提升呈线性增长。至21日龄时，番石榴副产物的添加并未抑制肉鸡的生产性能。各处理对肉鸡十二指肠与空肠的绒毛高度、隐窝深度以及绒毛隐窝比均无显著影响。而番石榴副产物的添加可降低回肠的隐窝深度，并使绒毛隐窝比呈线性提升。胸肌与大腿肉的pH值及比色参数均无显著差异。随着副产物添加水平的提升，大腿肉的TBARS值在添加量为0.72%时降至最低，表明此时大腿肉的脂质稳定性更佳。
综上，番石榴副产物可作为肉鸡饲料中的替代性抗氧化添加剂，其既不会抑制肉鸡的生产性能，还可改善肉鸡大腿肉的肉品品质。