ABSTRACT For a long time, it has been said that eggshell quality decreases as eggs increase in size, but this increase is seen as the breeder age advances. Therefore, the present study aimed to evaluate the age and egg weight effect on Cobb 500 broiler breeders on eggshell quality. The quality measures tested were eggshell and mineral matter percentage, eggshell surface, shape and eggshell index, eggshell and membrane thickness and specific gravity. Eggs from 27, 31, 36, 40, 46, 48, 53, 58 and 63 week-old breeders were classified as eggs with a constant weight ranging from 63.8 ± 0.2; and eggs with increasing weight, according to age, being: 55.8g; 60g; 62.2g; 64.2g; 65.2g, 66.6g, 68.1g, 69.9g and 72.5g, respectively. The eggs weight did not influence the eggshell percentage and the specific gravity in seven of the nine tested ages, while for mineral matter in six of the nine studied ages. The shape and shell index, shell and membrane thickness are characteristics independent of egg weight. As the Cobb 500 broiler breeder age advanced, the mineral matter concentration and specific gravity maintained constant, the membrane thickness (R2>70) reduced, and other studied variables were influenced in the same way for both treatments. Thus, the eggshell quality decrease with the advancing age cannot be attributed solely to the increase of egg weight with consequent increase in the eggshell volume and the surface, but there are also age-related factors.

ABSTRACT The objective of this study was to evaluate the performance and carcass yield of broilers submitted to heat stress during different rearing stages. A total of 840 one-day-old CobbAvian48TM male broilers were housed in an experimental house equipped with conventional ventilation system and foggers. Birds were distributed according to a completely randomized design into four treatments, with six replicates of 35 birds each. The treatments consisted of: T1 (control) - birds reared under natural temperature and relative humidity conditions from 1 to 42 days of age; T2 - birds submitted to heat stress (HS) from 16 to 21 days of age; T3 - birds submitted to HS from 22 to 42 days of age; and T4 - birds submitted to HS from 16 to 42 days of age. Birds were submitted to heat stress daily for one hour (12:00-13:00h).On day 42, performance data were determined. Six birds per replicate were selected and sacrificed to obtain carcass, parts, and giblet weights and yields. Performance parameters were not influenced by the treatments. Broilers submitted to 1-h cyclic heat between 16 and 42 days of age presented lower deboned breast weight compared with those maintained in natural temperature and relative humidity conditions. It was concluded that the performance of broilers submitted to short cyclic heat periods is not impaired.

ABSTRACT The objective of this study was to evaluate the effect of using exoenzyme phytase in broiler's diets on digestibility of nutrients, feed energy and tibia bone mineralization. A completely randomized design was used, with the following treatments: sorghum with dicalcium phosphate (SDP), corn with dicalcium phosphate (CDP), sorghum with meat and bone meal (SMBM), sorghum with valued phytase (SVP) and sorghum with phytase without valued (SPWV). For digestibility analysis, eighty 15 day old broilers were used, a total of 1400 male Hubbard Flex chickens, which were submitted to total excreta collection to obtain the percentages of food digestibility, crude protein, ether extract, apparent metabolizable energy, calcium and phosphorus while for tibias mineralization. Six birds per treatment were used, where determination of mineral matter, calcium and phosphorus were performed. Metabolizable energy (ME) and apparent metabolizable energy corrected for nitrogen (AMEn) of the feed were also calculated. Data were subjected to variation analysis and the average compared by 5% Tukey test. There was no difference between treatments for the digestibility at 15-20 day old as well as for the feed energy values, but the diets with phytase had higher phosphorous percentage values for tibia bone mineralization, demonstrating that exogenous phytase enzyme is able to hydrolyze phytate origininated from plant and release the phosphorus for assimilation by animals, acting as a substitute for phosphorus plant sources.

ABSTRACT This study aimed to evaluate the effect of maltodextrin on performance of chicks passed through four fasting periods. A completely randomized design was performed, consisting of three treatments (1 - control, 2 - 4% saccharose; 3-4% maltodextrin 20) and four fasting periods after hatching (0, 12, 24 and 36 hours) with four replications, totaling 1920 birds of both sexes. The studied variables were: water intake in the first 12 hours, average food intake, average body weight and real feed conversion. Data was submitted to analysis of variance and means were compared with each other by Dunnett test at 5% significance. The use of additives and imposing of different fasting periods did not influence the performance at 42 days old. Therefore, fasted chicks consumed significantly more water. At 7 days old, chicks fasted showed higher body weight and higher feed intake, however, the viability did not suffer any influence, the weight remained higher after 21days with the fast imposition and there was no influence on other variables. There was no effect of fasting on broiler chiken's performance at 42 days old. The inclusion of sucrose and maltodextrin to drinking water stimulated the chick´s water intake and provided higher viability after seven days old.

ABSTRACT An experiment was conducted to compare three nutritional programs, which were developed with tannin-free grain sorghum based diets, evaluating performance, carcass yield and bromatological composition of the pectoral muscle of broilers. A total 1360 chicks mixed (50:50), from one to 42 days old Hubbard Flex Broilers, were housed in a completely randomized design consisting of treatments and 10 replicates each, distributed as follows: three programs with whole sorghum grain based diets (nutritional program with daily adjustment, nutritional program with every three days adjustment and nutritional program with four stages and a program with ground and whole sorghum grain based feed (four stages). The cumulative performance was evaluated at, 21 and 42 days, determining feed intake, weight gain, feed conversion and viability. At 42 days, the yield of eviscerated carcass, breast (full and boneless), thighs/drumsticks and wings and breast composition were evaluated. Nutritional adjustments showed better feed conversion, did not affect the carcass, commercial cuts yield and had a good breast meat quality. It can be concluded that daily feed programs could be performed in poultry industry with the mixture of whole sorghum grains and concentrates directly on farms contributing to better logistics and feed transportation cost.

ABSTRACT The objective of the study was to evaluate the effect of nutritional plans on the productive and economic performance of Hubbard Flex broiler chickens. A completely randomized experimental design was applied, consisting of five treatments. Treatments consisted of five different nutritional plans: a basal diet containing the nutrient and energy levels recommended by literature and designated reference diet; two diets containing 1.5% and 3% lower levels than the reference diet; and two diets containing 1.5% and 3% higher levels than the reference diet (-3%, -1.5%, reference plan, +1.5% and +3%). Feed intake (FI), body weight (BW), feed conversion rate (FCR), livability (L) and productive efficient index (PEI) were determined when broilers were 42 days old. Broilers were processed, and carcass and parts (breast fillet, leg, and wings) yields were determined. The economic viablility of the nutitional plans was evaluated as a function of feed cost/kg live and carcass weights, economic efficiency index (EEI), and cost index (CI). Feed intake and the feed conversion rate decreased as dietary nutrient and energy levels increased. Feed cost/kg live weight, economic efficiency index, and cost index cost increased as dietary nutrient and energy levels increased. Feed intake, feed conversion ratio, production efficiency index, and breast yield improved with increasing nutritional and energy levels. However, worse economic results were obtained with higher nutritional and energy levels.

ABSTRACT This study aimed at evaluating the replacement of inorganic copper, manganese, and zinc sources by organic sources in the diet of laying hens during the second laying cycle in trace mineral excretion, egg production, and eggshell quality. Two hundred and fifty 100-week-old Dekalb hens were distributed according to a completely randomized design into five treatments with five replicates of ten birds each. The control treatment consisted of a basal diet with all trace minerals in the inorganic form. The other treatments consisted of a basal diet with a mixture of the minerals copper, manganese, and zinc in the organic form with concentrations of 100%, 90%, 80%, and 70% of the levels of inclusion of inorganic mineral sources in the control treatment. Trace mineral excretion was determined in five layers per treatment by the method of total excreta collection. Excreta trace mineral contents were determined by atomic absorption spectrophotometry. Egg production and eggshell quality were determined by the mass of the eggs and the egg specific gravity, respectively. For all trace minerals examined, the dietary supplementation with organic sources reduced trace mineral excretion compared with the control group, even at 70% inclusion level, without compromising egg production or eggshell quality. The replacement of the inorganic trace mineral sources by organics source effectively reduced the excretion of copper, manganese, and zinc by laying hens in the second laying cycle.

The objective of the present study was to evaluate the supply of a specific-male diet on rooster body weight, hatchability, and fertility. Two diets were supplied during the egg production period: treatment 1, diet formulated for females and containing, in average, 2,830 kcal ME/kg and 15% CP; and treatment 2, diet specifically formulated for male broiler breeders, containing 2,750 kcal ME/kg and 13.5% CP. In the experiment, 26 flocks, with approximately 7,000 females and 840 males each, belonging to the same broiler breeder commercial strain, were distributed into 26 houses (1200m²) on the same farm, and submitted to the same management practices. Body weight was evaluated in 13 flocks per treatment and for five weeks (45, 50, 55, 60, 65), and hatchability and fertility in four incubation lots per treatment and for the same weeks. Data were evaluated by the analysis of mixed models for repeated measurements, using the PROC MIXED of SAS 9.3 (SAS Institute Inc., Cary, NC, USA), and means were compared by the test of Tukey-Kramer at 5% significance level. The specific-male diet allowed body weight control during all analyzed weeks and promoted high hatchability and egg fertility. The increase in the number of chicks hatched demonstrates the economic viability of feeding a specific diet for male broiler breeders.

The aim of this study was to evaluate the incidence of footpad dermatitis and quality of broilers litter fed with sorghum grain and diets based in corn. It was used 544 male and female chicks, distributed in a completely randomized design with two treatments and eight replications. The chicken feed was formulated and produced from corn, soybean meal and sorghum grain. In the formulation were kept constant levels of energy and protein in accordance with the following treatments: A. Control (diet based on corn and soybean meal); B. Grain sorghum (Whole Sorghum + soybean meal). At 35 and 42 days were evaluated mineral matter (A %), calcium (Ca%), phosphorus (P%), pH and dry matter (DM %) of the poultry litter. To evaluate the footpad dermatitis were evaluated eight feet per treatment by visual analysis. At 35 and 42 days of age DM % MM (%), Ca (%) P (%) and pH of poultry litter no difference (p>0.05) was found between the treatments and the type of ingredient in the birds' diet is not related (p>0.05) with the incidence of footpad dermatitis. The incidence of footpad dermatitis and the quality of the litter weren't influenced by the type of the ingredient used in diet.

In broiler feed manufacturing, grinding may significantly increase costs due to electric energy use. This study evaluated the performance and the morphometrics of the gastrointestinal tract of broilers. According to a completely randomized experimental design, 2,400 birds (1,200 males and 1,200 females) were submitted to five treatments of eight replicates each. Treatments consisted of diets based corn or sorghum as follows: ground corn (A), broken corn (B), ground sorghum (C), ground (50%) and whole (50%) sorghum (D) and whole sorghum (100%; E). Pre-starter feeds (1 to 8 days), based on corn or sorghum, were produced only with ground grains. The study was divided in two trials: males and females. The results were submitted to analysis of variance (p<0.05) and Tukey's test. Feed intake, live weight, feed conversion ratio, and livability of 21- and 42-day-old male and female broilers were not affected by the treatments. This demonstrates that broiler performance is not influenced by sorghum physical form and that broilers fed sorghum-based diets presented similar performance as those fed corn-based diets. Gizzard and small intestine were heavier when whole sorghum grains was included in the diet. It was concluded that whole sorghum grains can be included in broiler feeds with not detrimental effects on performance.

The objective of this study was to evaluate the performance and carcass characteristics of broilers fed exclusively vegetable diets and diets containing animal meal with the addition of creatine or not after day 8. In the experiment, 1080 one-day-old male chicks were distributed according to a completely randomized experimental design into six treatments with six replicates each. A control diet based on corn and soybean meal was formulated, to which animal meals and creatine were included or not. Diets were formulated to contain equal mineral (calcium, phosphorus and sodium) and amino acid (available methionine + cystine, lysine and threonine) levels. The following treatments were applied: A. control (diet based on corn and soybean meal); B. control + creatine (600g/ton); C. inclusion of 5% meat and bone meal (MBM), D. inclusion of 5% MBM + creatine (600g/ton), E. inclusion of 5% blood meal (BM), F. inclusion 5% BM + creatine (600g/ton). Weight gain, feed intake, feed conversion, carcass yield and viability were evaluated. At 42 days of age, BM dietary inclusion impaired weight gain and feed conversion ratio. The inclusion of MBM affected only feed conversion ratio. The addition of creatine ito the diet with BM improved weight gain when compared with the BM diet with no creatine. The addition of creatine to the diet containing 5% BM improved weight gain when compared with the same diet without the use of the additive.