Cristiane Regina do Amaral Duarte

Use of Vitamin D3 and Its Metabolites in Broiler Chicken Feed on Performance, Bone Parameters and Meat Quality

The objective of this experiment was to assess the use of different vitamin D metabolites in the feed of broiler chickens and the effects of the metabolites on performance, bone parameters and meat quality. A total of 952 one-day-old male broiler chicks were distributed in a completely randomised design, with four treatments, seven replicates and 34 birds per experimental unit. The treatments consisted of four different sources of vitamin D included in the diet, D3, 25(OH)D3, 1,25(OH)2D3, and 1α(OH)D3, providing 2000 and 1600 IU of vitamin D in the starter (1 to 21 d) and growth phases (22 to 42 d), respectively. Mean weight, feed:gain and weight gain throughout the rearing period were less in animals fed 1α(OH)D3 when compared with the other treatments (p<0.05). No significant differences were noted among the treatments (p>0.05) for various bone parameters. Meat colour differed among the treatments (p>0.05). All of the metabolites used in the diets, with the exception of 1α(OH)D3, can be used for broiler chickens without problems for performance and bone quality, however, some aspects of meat quality were affected.

Milheto na alimentação de codornas japonesas

Two experiments were carried out to determine the energy value of the pearl millet, and the effects of its use, as energetic source, in the diets of Japanese quails on the performance and eggs quality, as well as to accomplish an economic evaluation in order to verify the viability of using the pearl millet. Experiment 1 was conducted by using 72 japanese quails distributed in metabolism cages. A completely randomized experimental design was conducted, with two treatments, six replicates and nine birds per experimental unit. The crude energy of pearl millet were 4142,15kcal/kg (as dry matter) and the apparent metabolizable energy 3770,12kcal/kg (as dry matter ) and 12.58% crude protein. Experiment 2 utilized 336 japaneses quails distributed in a completely randomized experimental design, with six treatments, seven replicates and eight birds per unit. The treatments consisted in diets with different levels of pearl millet (0 to 100%). There was a significant effect on feed intake witch increased with the levels and for feed conversion in the levels 80 and 100%. The yolk pigmentation index a decreased by increasing of pearl millet. Corn can be replaced by pearl millet for 100% without compromising the egg production (%) and egg quality, except the yolk pigmentation. The greater economic viability was calculated at 40% of inclusion of pearl millet. However, it must be considered the necessity of pigments inclusion.

Effect of dietary restriction and hay inclusion in the diet of slow-growing broilers

The objective of this study was to evaluate the effect of dietary restriction and inclusion of alfalfa (Medicago sativa L.) and Bermudagrass (Cynodon dactylon cv Coastal) hays in the diets of ISA Label JA57 slow-growing male broilers on performance, gastrointestinal tract characteristics, and economic viability. A total of 272 broilers at 21 days old were distributed in a randomized experimental design with four treatments, four replicates, and 17 birds per experimental unit. The treatments consisted of ad libitum concentrated feed (control intake), feed restriction (80% of the control intake), and feed restrictions with supplementation of alfalfa hay (80% of the control intake+20% alfalfa) or Bermudagrass hay (80% control intake+20% Bermuda). Dietary restriction, with and without hay inclusion, negatively affected (P<0.05) the weight gain of the birds; however, feed conversion was improved (P<0.05) for animals that underwent only restricted feeding, which also had the best economic indices. Birds subjected to dietary restriction and inclusion of hays showed changes (P<0.05) in the gastrointestinal organs and intestinal morphology.

Performance, diameter of muscle fibers and gene expression of mechanistic target of rapamycin in pectoralis major muscle of broilers supplemented with leucine and valine

Abstract: Two experiments were performed to study the interaction between the standardized ileal digestible (SID) leucine (Leu) and valine (Val) levels on the mRNA expression of genes involved in the mechanistic target of rapamycin (mTOR) pathway (experiment I) and determine the requirement of these amino acids in low-protein diets, and their effects on performance, serum parameters and muscle fiber diameters of broilers (experiment II) from day 1 to day 21 post hatch. Broiler chickens were distributed in a completely randomized design in a 3 × 3 and 5 × 5 factorial arrangement for a total of 9 and 25 treatments in experiments I and II, respectively. There was no (P > 0.05) interaction between the SID Leu and Val levels on mRNA expression of mTOR, S6 kinase 1 (S6K1), 4E-binding protein-1 (4EBP1), eukaryotic elongation factor 2 (eEF2), and insulin-like growth factor-1 (IGF-1) genes in pectoralis major muscle. Leucine supplementation increased (P < 0.05) mRNA expression of mTOR and S6K1 genes in muscle tissue, whereas Val supplementation did not affect (P > 0.05) mRNA expression of the genes investigated. Interaction was observed (P < 0.05) between dietary Leu and Val levels on feed intake and gain:feed. Leucine supplementation may stimulate mRNA expression of mTOR and S6K1 genes in pectoralis major muscle of broilers from day 1 to day 21 post hatch. The SID Leu and Val levels required for the optimization of feed intake, weight gain, and gain:feed in low-crude protein diets for broiler chickens from day 1 to 21 post hatch were estimated at 1.29% and 0.96%, 1.28% and 0.92%, and 1.27% and 0.91%, respectively; however, these requirements may be greater to maximize muscle fiber growth.

Intervalo para o alojamento e níveis de lisina, em dietas baseadas no conceito de proteína ideal, sobre o desenvolvimento muscular e rendimento de carcaça de frangos de corte

This study aimed to study the effects of delayed placement (IA) and dietary lysine levels (LD) in initial diets on breast muscle development and carcass yield of broiler chickens. For this, 1,760 male Cobb500 chicks were allocated randomly to eight experimental groups according to a 2x4 factorial arrangement for 4 IAs (12, 24, 36 and 48h) and 2 levels of LD (1.143 and 1.267%) with four replicates and 55 chicks per experimental unit. Met+Cys, Thr and Trp were balanced according to the ideal protein concept. There were no significant interactions between LD and IA on variables evaluated. The highest breast weight and breast fillet weight at 21 days old and body weight at 43 days old were obtained with the dietary lysine level of 1.143%. The breast weight, breast fillet weight and muscle fiber diameter at 21 days old, body weight, carcass weight and legs weight at 43 days old decreased linearly according to the increase of the delayed placement. The results of this study suggest that the 1.143% DL level improves the breast muscle development at 21 days old and chicken body weight at 43 days old, and the shortest delayed placement improves the breast muscle development during the initial phase and higher carcass yield and legs at the slaughter.