ABSTRACT The aim of this study was to evaluate the effect of digestible threonine supplementation in the starter diet on the performance, intestinal parameters, and nutrient metabolism of broilers derived from breeders of different ages. In total, 480 one-day-old Cobb chicks, derived from 38-or 49-week-oldbreeders, were housed in experimental battery cages until 21 days of age and fed four different threonine levels (800, 900, 1,000, or 1,100 mg/kg) in the starter feed. A completely randomized experimental design in a 2x4 factorial arrangement (breeder age x threonine levels) was applied, totaling eight treatments with five replicates of 12 birds each. Broilers from older breeders fed 800 mg digestible threonine/kg of diet presented higher weight gain, with a positive linear effect. There was also an interaction between breeder age and threonine levels for the weight gain of 21-d-old broilers supplemented at maximum level of 1,003 mg Thr/kg diet during the starter phase. There was no effect of breeder age or threonine levels on nutrient metabolism during the period of 17-21 days. There was no influence of breeder age or threonine levels in the starter diet on intestinal morphometric measurements, absorption area, or percentage of goblet cells.

ABSTRACTAn experiment was conducted to evaluate the performance and nutrient metabolizability of broilers fed diets containing fumonisin B1 (FB1) and an esterified glucomannan (EGM). In total, 420 male broilers were distributed according to a 3 x 2 + 1 factorial arrangement, corresponding to three FB1 exposure times (seven, 21, or 35 days), two dietary glucomannan addition levels (0 or 0.1% EGM), and control diet, totaling seven treatments. The following diets were fed: 1) Control diet, 2) pre-starter diet containing FB1, 3) pre-starter diet containing FB1 and 0.1% EGM, 4) starter diet containing FB1, 5) starter diet containing FB1 and 0.1% EGM, 6) grower diet containing FB1, and 7) grower diet containing FB1 and 0.1% EGM. On d 7, broilers fed FB1 presented lower body weight gain and feed intake (p<0.05) compared with control treatment. On d 21, no significant performance differences were detected among treatment groups (p>0.05). At 35 days of exposure to FB1 body weight gain was reduced (p<0.05) compared with broilers fed fumonisin B1 for seven days. From 4 to 7 days and 18 to 21 days of age, FB1 reduced nutrient metabolizability (p<0.05). From 36 to 39 days of age, the EGM allowed maintaining apparent metabolizability for ether extract. It was concluded that the EGM did not reduce FB1 effects on performance or nutrient metabolizability in broilers, except for apparent metabolizability of ether extract.