Effects of stocking density and climate region on performance, immunity, carcass characteristics, blood constitutes, and economical parameters of broiler chickens

ABSTRACT This experiment was conducted to evaluate the effects of stocking density and climate region on performance, immunity, carcass characteristics, blood plasma, and economic parameters of the Ross strain of broiler chickens. The effects of four climates (mild and humid, semi-arid, alpine, and hot and dry) and four densities (10, 15, 17, and 20 chicks/m2) were studied as a completely randomized design with 4×4 factorial arrangement of treatments. The results showed that the density had a significant effect on feed intake and feed conversion ratio in the starter period and on body weight gain in the grower and the whole periods of the experiment. Moreover, both climate and density had a significant impact on economic performance (live weight, survival rate, production index, meat production/m2, and profitability). The mild and humid climate and the density of 17 chicks/m2 had the most economic benefit compared with other treatments. The climate type had a significant effect on the relative weights of the breast, wings, neck, proventriculus, and ileum. The effects of climate and density on glucose, triglyceride, very low-density lipoproteins (VLDL), high-density lipoproteins (HDL), LDL/low-density lipoproteins (HDL), total protein and globulin were significant. In addition, the effect of climate on the antibody titer against sheep red blood cells (except for immunoglobulin G on day 28) was significant.

摘要 本实验旨在评估饲养密度与气候区域对罗斯（Ross）肉鸡品系的生产性能、免疫机能、屠宰特性、血浆指标及经济参数的影响。本研究采用完全随机设计，设置4×4双因素处理组，探究4种气候类型（温和湿润、半干旱、高寒、炎热干燥）与4种饲养密度（10、15、17、20只/m²）的交互效应。结果显示，饲养密度对肉鸡育雏期的采食量与料重比，以及育成期和全实验周期的体增重均具有显著影响。此外，气候类型与饲养密度均对经济性能（活重、存活率、生产指数、单位面积肉产量及利润率）存在显著影响。相较于其他处理组，温和湿润气候搭配17只/m²的饲养密度可获得最优经济效益。气候类型对胸肌、翅膀、颈部、腺胃及回肠的相对重量具有显著影响。气候与饲养密度对血糖、甘油三酯、极低密度脂蛋白（VLDL）、高密度脂蛋白（HDL）、低密度脂蛋白（LDL）、总蛋白及球蛋白水平均存在显著影响。此外，气候类型对绵羊红细胞抗体滴度（28日龄免疫球蛋白G除外）具有显著影响。