ABSTRACT The effect of fine wheat bran (FWB) as a methyl donor source on performance, metabolism, body composition and blood traits of growing broilers was studied. Three hundred and twenty broilers from eight to 28 d of age, distributed in a randomized block design, with five treatments and eight replicates of eight animals each were used. The experimental diets were: NC, formulated with 72% of the Met+Cys requirement; Met, formulated with 85% of the Met+Cys equivalents by DL-methionine addition; Bet, formulated with 85% of the Met+Cys equivalents by anhydrous betaine addition; Fwb-, formulated with 72% of the Met+Cys requirement and 20% FWB; and Fwb+, formulated with 85% of the Met+Cys requirement and 20% FWB. Feed intake was reduced (p<0.05) by FWB inclusion but the feed conversion ratio was the same (p>0.05) between the positive control diets. Supplementation of DL-methionine and anhydrous betaine showed the same (p>0.05) metabolizability of nutrients. Treatments with higher DL-methionine levels (Met and Fwb+) promoted more weight of feathers (p<0.05). Animals fed with FWB showed the lowest (p<0.05) body gains. In conclusion, FWB inclusion did not promote methyl radicals supply.

The objectives of the present study were to determine the parameters of Gompertz equations and to determine curves and growth rate, feed intake and body component deposition, as well as allometric coefficients of body water, protein, and fat relative to live weight of male and female broilers of intermediate performance (C44) and high performance (Cobb-500) genetic strains. In total, 384 one-d-old chicks were distributed into four treatments: male Cobb 500, male C44, female Cobb 500, and female C44, with six replicates of 16 birds, according to a completely randomized experimental design. Average body weight, weight gain, and feed intake were weekly determined, and six birds, representing the average weight of each treatment, were sacrificed to determine body composition. Growth curves were built applying Gompertz function, with excellent fit, and growth, feed intake, and tissue deposition rates were obtained by its derivatives. Superior growth rate was obtained for Cobb 500 male broilers. This genetic strain has higher feed intake capacity, which is achieved earlier than in the C44 strain. Protein and fat deposition maturity was reached earlier in males than in females in Cobb 500. The allometric coefficients showed earlier maturity for body water in C44 and females. In terms of body protein, male Cobb 500 broilers reached maturity earlier than females and C44. Body fat deposition maturity was reached earlier in Cobb 500 than in C44. The Gompertz equations obtained in the present study efficiently described body growth, feed intake, and deposition of body components, with a coefficient of determination higher than 0.99.

In this study, 360 male broilers, out of which 240 of a fast-growing strain (Cobb500), and 120 of a slow-growing strain (Label Rouge), were used to evaluate the effect of dietary fiber on digesta transit time and digestive metabolism during the period of 1 to 42 days of age. A completely randomized experimental design with a 3x2 factorial arrangement was applied, consisting of three groups of birds (slow-growing - SG; fast-growing fed ad libitum - FGAL; and fast-growing pair-fed with SG broilers - FGPF) and two iso-protein diets (a 3100 kcal ME/kg low-fiber diet - LFD- and a 2800 kcal ME/kg high-fiber diet - HFD- with 14% wheat bran and 4% oat hulls). HFD-fed birds presented lower ME retention (p < 0.001) and lower dry matter metabolizability (DMM) (p < 0.001), which is possibly related to the shorter digesta transit time observed in these birds (p < 0.001). DMM was reduced with age, whereas metabolizable energy remained almost constant (p < 0.001) independently of strain. This may be related to the increase in feed intake as birds age. The slow-growing strain did not present better utilization of the high-fiber diet as compared to the fast-growing strain in none of the analyzed ages, even though showing a significant better use of fiber and dietary energy from 31 days of age.

The experiment was conducted to evaluate the effect of dietary fiber on the performance and energy balance of broiler chickens of a fast-growing strain (Cobb500) and a slow-growing strain (Label Rokens during the period of 1 one to 42 days of used In total, 360 male broilers (240 fast-grorain and 120 slow-grtrain)were, housed in collective cages. A completely randomized experimental dewith in a 3x2 factorial arrangement was applied, consisting of three groups of birds (slow-growing - SG; fast-growing fed ad libitum - FGAL; and fast-growing pair-fed with SG broilers - FGPF) and two iso-protein dis (a 3100 kcal ME/kg low-fiber diet and a 2800 kcal ME/kg high-fiber diet- Hwith containing 14% wheat bran and 4% oat hulls). Dietary fiber level did not affect feed intake (FI); however, it resulted in lower weight gain (WG) and worse feed conversion ratio (FCR) (p < 0.001) in birds fed the HFD diet due to its lower energy content. The FGPF group presented higher WG than SG and better FCR (p < 0.001), indicating that fast-growing birds present better performance than SG broilers, even under restricted feed intake. The SG group retained more energy relative to body weight (p < 0.001), which is associated to higher body fat retention in this strain (p < 0.001). The slow-growing strain did not present better use of high-fiber diet than fast-growing strain as expected.