Mohsen Zaker_Jafari; Mehrdad Mohammadi; Maziar Mohiti-Asli
Volume 24, Issue 4 , December 2022, , Pages 477-488
Abstract
The effect of chick initial body weight and dietary nutrients density on growth performance and immune response were investigated using 360 Ross 308 one-day-old straight run chicks (mixed sex) in a completely randomized design with 2×3 factorial arrangement of treatments, four replicates and 15 ...
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The effect of chick initial body weight and dietary nutrients density on growth performance and immune response were investigated using 360 Ross 308 one-day-old straight run chicks (mixed sex) in a completely randomized design with 2×3 factorial arrangement of treatments, four replicates and 15 birds per replicate. The initial body weight of chicks was grouped as 42±1 g (standard weight); 38±1 g (light weight; 10% under standard weight); 46±1 g (heavy weight; 10% over standard weight) while the nutrients density of the diet was either 5% lower than the nutritional recommendation of Ross 308 (typical commercial diet in Iran), or as recommended by Ross 308 manual (high-density diet). Chickens fed the high-density diet had higher daily weight gain and lower conversion ratio than chickens fed the typical diets (P<0.05). The effect of dietary density and initial body weight of chicks on carcass components and weight of internal organs were not significant except for heart. Broilers fed the high-density diet and heavy weight had higher antibody titers to sheep red blood cell (P<0.05). Light chicks fed the high-density diets had greater total anti sheep red blood cell and immunoglobulin G titers than light chicks fed the typical diets (P<0.05). Results indicate that feeding light chicks with high-density diets increases their growth rate compared to the chicks with standard or heavy weights. Moreover, feeding diets with a high density of nutrients to light chicks can improve immune responses.