Are genetically lean broilers more resistant to hot climate?
1. Genetically lean (LL) or fat (FL) male chickens were exposed to either high (32 degrees C) or control (22 degrees C) ambient temperature up to 9 weeks of age. They were fed on one of two isoenergetic diets differing in protein content: 190 or 230 g/kg. 2. At 22 degrees C, weight gain of LL broilers was the same as in FL chickens, but at the high temperature LL birds grew to a greater weight than FL ones. 3. Food conversion efficiency was not affected by ambient temperature in LL chickens but was depressed in FL ones at 32 degrees C. 4. Increasing dietary protein content did not alleviate heat-induced growth depression irrespective of the genotype. 5. Gross protein efficiency was higher in LL chickens and was less depressed at 32 degrees C than in FL birds. 6. Fat deposition decreased with increasing protein concentration at normal temperature in both genotypes; at high temperature, high protein content enhanced fatness, particularly in LL chickens. 7. Thus, genetically lean broilers demonstrated a greater resistance to hot conditions: this was indicated by enhanced weight gain and improved food and protein conversion efficiencies.
Geraert
P A
PA
Station de Recherches Avicoles, Institut National de la Recherche Agronomique, Nouzilly, France.
Guillaumin
S
S
Leclercq
B
B
D000821:Animal Feed; D000818:Animals; D001823:Body Composition; D001835:Body Weight; D002645:Chickens / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D002980:Climate; D004044:Dietary Proteins / Q000494:pharmacology; D006358:Hot Temperature; D008297:Male
D004044:Dietary Proteins