Food restriction early or later in life and its effect on adaptability, disease resistance, and immunocompetence of heat-stressed dwarf and nondwarf chickens.
1. Dwarf and nondwarf chickens placed under 60% food restriction from either 4 to 6 (early) or 24 to 26 (late) days of age were exposed to high ambient temperatures (35 +/- 2 degrees C) from 36 to 43 d of age. 2. As measured by heterophil/lymphocyte (H/L) ratios, stress response to food restriction was similar at both ages for dwarfs while less at the younger than the older age for nondwarfs, resulting in a significant food restriction interaction of genotype by age. 3. Nondwarf chickens food restricted at the younger age had smaller increases in H/L ratios, improved resistance to marble spleen disease infection and greater growth than those restricted at the older age or fed ad libitum in response to the high ambient temperatures. 4. For dwarf chickens feeding regimen had no influence on response to the environmental insults. 5. Antibody response to sheep erythrocyte antigen was not affected by genotype or feeding regimen.
Zulkifli
I
I
Animal and Poultry Sciences Department, Virginia Polytechnic Institute and State University, Blacksburg 24061-0306.
Dunnington
E A
EA
Gross
W B
WB
Siegel
P B
PB
D000818:Animals; D001835:Body Weight; D002645:Chickens / Q000502:physiology*; D004032:Diet; D004198:Disease Susceptibility; D002149:Energy Intake; D005260:Female; D005838:Genotype; D006128:Growth / Q000502:physiology*; D006358:Hot Temperature; D007121:Immunocompetence; D007958:Leukocyte Count; D007962:Leukocytes / Q000502:physiology; D008214:Lymphocytes / Q000502:physiology; D008297:Male; D013045:Species Specificity