title: Optimum threonine requirement of laying hens.
abstract: 1. One experiment was conducted with medium weight laying hens to determine their threonine requirement between 28-38 weeks. 2. Two threonine-limiting diets of identical protein quality (summit-dilution) were used and, by dilution, ten protein contents were produced supplying 2.7 to 5.4 g total threonine/kg diet. The diet with the lowest protein was also supplemented with synthetic L-threonine. Each diet was fed to 5 groups of 24 laying hens. 3. The daily threonine requirement of the individual laying hens was estimated by direct methods to be 8.7 mg/g egg output plus 43.49 mg/kg body weight for this experiment. Calculated optimum intakes of threonine for various ratios of costs of input to value of output are tabulated. For example, for a flock of medium weight laying hens producing an average of 50 g daily egg mass, the optimum threonine intake (mg/hen d) varied between 700 and 710 for cost ratios (k-values) varying between 0.002 and 0.001.
authors.affiliation: Rijksstation voor Kleinveeteelt, Governmental Centre of Agricultural Research Gent, Belgium.
authors.forename: G
authors.initials: G
authors.lastname: Huyghebaert
authors.forename: E A
authors.initials: EA
authors.lastname: Butler
mesh_terms: D000596:Amino Acids / Q000008:administration & dosage; D000704:Analysis of Variance; D000821:Animal Feed; D000818:Animals; D001835:Body Weight; D002645:Chickens / Q000502:physiology*; D004044:Dietary Proteins / Q000008:administration & dosage; D004435:Eating; D004531:Eggs / Q000592:standards*; D005260:Female; D010058:Oviposition; D013912:Threonine / Q000008:administration & dosage* / Q000378:metabolism
chemical_list: D000596:Amino Acids; D004044:Dietary Proteins; D013912:Threonine