title: Food intake adjustments of chicks: short term reactions to deficiencies in lysine, methionine and tryptophan.
abstract: 1. Two experiments were conducted to compare food intake responses of broiler chicks fed diets varying in lysine, methionine, and tryptophan. Diet D was formulated to create simultaneous deficiencies of lysine, methionine, and tryptophan. Diet A matched National Research Council (1984) recommendations for broilers, and diets B and C were, respectively, 2:1 and 1:2 mixes of diets A and D. 2. Short-term food intake can provide information on the sequences of adaptation of chicks to a diet deficient in essential amino acids. 3. Chicks consumed 26% less of diet D than A during the first 24 h posthatch. When chicks fed diet A or D to 7 d of age were then fed one of 4 diets singly, within 24 h intake was lowest for chicks fed diet D. Within 48 h, food intake of diet C was more than that of diet D and less than that of diet A, while for diet B intake was more than of diet D but not different from diet A. 4. In the second experiment, chicks were fed diet A to 8 d and then diets A or D alone or given a choice of diets A and D from 8 to 20 d of age. Within 4 to 8 h, food intake of chicks fed diet D alone decreased markedly followed by partial recovery within 24 h. In a choice setting, consistent preference of Diet A over Diet D was observed within 7 h followed by stabilisation at about 65% diet A to 35% diet D. 5. Chicks fed diet D alone from 8 to 20 d of age, then placed in the same choice situation preferred diet A to D with a delay of less than one h and stabilisation at about 85%. Chicks provided a choice of diets A and D from 8 to 20 d, and then diet D alone reduced their food intake more quickly than those not given a choice initially. 6. Broiler chicks appear to react to amino acid deficiencies within a short period (hours) by adjusting their feed intake and/or selection. The response is influenced by age and prior experience.
authors.affiliation: Station de Recherches Avicoles, Institut National de la Recherche Agronomique, Nouzilly, France.
authors.forename: M L
authors.initials: ML
authors.lastname: Picard
authors.forename: G
authors.initials: G
authors.lastname: Uzu
authors.forename: E A
authors.initials: EA
authors.lastname: Dunnington
authors.forename: P B
authors.initials: PB
authors.lastname: Siegel
mesh_terms: D000821:Animal Feed; D000818:Animals; D001835:Body Weight; D002645:Chickens / Q000378:metabolism*; D004032:Diet; D004435:Eating; D008239:Lysine / Q000172:deficiency*; D008715:Methionine / Q000172:deficiency*; D013997:Time Factors; D014364:Tryptophan / Q000172:deficiency*
chemical_list: D014364:Tryptophan; D008715:Methionine; D008239:Lysine