Effects of acute versus chronic heat stress on broiler response to dietary protein
Two experiments were conducted to determine broiler response to dietary protein during short (1 wk) or prolonged (>3 wk) heat stress (HS). In experiment 1, 21-d-old birds were kept at 20.3°C (thermoneutral; TN), 27.3°C (medium temperature; MT), or 31.4°C (high temperature; HT) and fed diets with 18, 20, 23, or 26% CP for 21 d. Each treatment consisted of 2 blocks of 3 replicates of 15 birds. In experiment 2, broilers were fed diets with 18 or 26% CP or fed ad libitum 2 diets with 10 or 30% CP.
... with 10 or 30% CP. Birds were kept at TN (23.5°C) or slowly introduced to HS from 7 to 14 d of age and kept at HT thereafter (chronic; CHS; 29.4°C), and a third group was moved to HT at 21 d (acute HS; AHS; 29.4°C). There were 16 replicates of 4 chickens per treatment distributed in 2 blocks. Performance, body composition, and protein deposition were ascertained from 21 to 28 d and from 28 to 42 d (short and prolonged exposures, respectively). Feeding high protein diets in experiment 1 resulted in linear im-(Key words: protein, acute heat stress, chronic heat stress, broiler) 2005 Poultry Science 84:1562-1569 Abbreviation Key: AHS = acute heat stress; BWG = body weight gain; CHS = chronic heat stress; FC = free choice; FI = feed intake; HS = heat stress; HT = high temperature; MT = medium temperature; TN = thermoneutral.