Abstract in English:During incubation of chicken embryos, environmental conditions, such as temperature, relative humidity, and CO2 concentration, must be controlled to meet embryonic requirements that change during the different phases of embryonic development. In the current review, the effects of embryo temperature, egg weight loss, and CO2 concentration on hatchability, hatchling quality, and subsequent performance are discussed from an embryonic point of view. In addition, new insights related to the incubation process are described. Several studies have shown that a constant eggshell temperature (EST) of 37.5 to 38.0°C throughout incubation results in the highest hatchability, hatchling quality, and subsequent performance. Egg weight loss must be between 6.5 and 14.0% of the initial egg weight, to obtain an adequate air cell size before the embryo internally pips. An increased CO2 concentration during the developmental phase of incubation (first 10 days) can accelerate embryonic development and hatchability, but the physiological mechanisms of this acceleration are not completely understood. Effects of ar increased CO2 concentration during late incubation also need further investigation. The preincubation warming profile, thermal manipulation, and in ovo feeding are new insights related to the incubation process and show that the optimal situation for the embryo during incubation highly depends on the conditions of the eggs before (storage duration) and during incubation (environmental conditions) and on the conditions of the chickens after hatching (environmental temperature).
Abstract in English:The mortality of passerines native of Southern Minas Gerais, Brazil, in August 2006 and the examination of sentinel free-range chicken eggs in August 2007 in an area surrounding a car battery lead smelter plant is described. The high levels of lead, as detected in the passerines (4.80-12.74 mg/kg) at the onset of mortality and at the follow-up sampling of the free-range chicken eggs (25.02-35.21 mg/kg in shells, 0.41-1.36 mg/kg in yolks and 0.40-0.75 mg/kg in the albumins), used as environmental sentinels, indicated the continuing lead pollution.
Abstract in English:An experiment was carried out to evaluate carcass traits of male and female broilers of two genetic strains (Paraíso Pedrês and Pescoço Pelado), slaughtered at 65, 75, 85 and 95 days of age, and reared under a semi-extensive production system. The following parameters were evaluated: body weight at slaughter (BWs), carcass weight (CW), carcass yield (CY), parts yield, including breast, drumstick, thighs, back, neck, feet, wings, abdominal fat pad (AF), and giblets (gizzard, heart, liver). Paraíso Pedrês males presented higher BWs and CW. Paraíso Pedrês females had higher breast yield. Thighs and drumstick yields were higher in Pescoço Pelado males. Back yield was similar at 85 and 95 days of age, wing yield declined with age. AF yield was higher in Paraíso Pedrês and in females. GY was affected by sex and slaughter age. The results of this work lead to the conclusion that Paraíso Pedrês males reach higher live and carcass weights at 85 and 95 days of age, and that breast yield is higher in this strain. On the other hand, Pescoço Pelado males present higher drumstick and thighs yields. Therefore, the choice of genetic strain, sex and slaughter weight will determine carcasses with different parts yield.
Abstract in English:Among the avian influenza A virus subtypes, H5N1 and H9N2 viruses have the potential to cause an influenza pandemic because they are widely prevalent in avian species in Asia and have demonstrated the ability to infect humans. This study was carried out to determined the seroprevalence of H9N2 avian influenza virus in different human populations in Fars province, which is situated in the south of Iran. Antibodies against H9N2 avian influenza virus were measured using hemagglutination-inhibition (HI) test in sera from 300 individuals in five different population in Fars province, including poultry-farm workers, slaughter-house workers, veterinarians, patients with clinical signs of respiratory disease, and clinically normal individuals, who were not or rarely in contact with poultry. Mean antibody titers of 7.3, 6.8, 6.1, 4.5, and 2.9 and seroprevalences of 87%, 76.2%, 72.5%, 35.6%, and 23% were determined in those groups, respectively. Higher prevalences were detected in poultry-farm workers, slaughter-house workers, and veterinarians, possibly due to their close and frequent contact with poultry.
Abstract in English:Considering the importance of drinking water and its effect on broiler performance, drinking water quality was studied using six different litter materials. The presence of coliform bacteria and Escherichia coli was investigated. The following litter materials were used in the trial: wood shavings, rice husks, chopped Napier grass (Pennisetum pupureum), 50% sugarcane bagasse (Saccharum L.) + 50% wood shavings, 50% sugarcane bagasse (Saccharum L.) + 50% rice husks, and plain sugarcane bagasse (Saccharum L.). A number of 1620 Ross® one-day-old chicks were reared in 54 pens measuring 4.5 m² each, equipped with a bell drinker and a tube feeder. Water samples were collected in sterile tubes on days 28 and 42 of the rearing period, and submitted to the laboratory for analyses. Microbiological data were organized by classes expressed in a logarithm scale, where the lowest contamination corresponds to class 1 and the highest contamination to class 4. Results showed that total coliform contamination was higher on day 28 than in the end of the rearing period, and that E. coli presence was detected during both analyzed periods. The litter materials that presented lower degree of water contamination, predominantly class 1, were sugarcane bagasse and 50% of sugarcane bagasse and 50% of rice husks.
Abstract in English:This experiment was conducted to evaluate the effect of some feed restriction regimes on the performance, carcass characteristics and hematological values of broiler chickens. A number of 480 one-day-old Cobb broilers were distributed into 24 floor pens and reared for 42 days. A basal diet was formulated according to the NRC (1994) recommendations for starter (1-11 d), grower (12-28 d) and finisher (29-42 d) periods. The restricted birds were fed 8 h per day from 7 to 21 (R7-21d), 14 to 28 d (R14-28d) or from 21 to 35d (R21-35d), while the control birds were fed ad libitum. Birds and feed were weekly weighed, and dead birds were submitted to necropsy to determine the cause of death. At the end of experiment, blood samples were taken from 3 birds per pen, birds were weighed, and organ weights were recorded. All birds in the feed restriction treatments had lower body weight gain and feed intake than those fed ad libitum. Feed conversion ratio (FCR) was better in birds under R7-21d as compared to the control group (p<0.05). R7-21d and R14-28d birds presented lower general mortality and death due to ascites as compared to ad libitum-fed broilers. The birds under R21-35d and R14-28d treatments had lower breast weight and abdominal fat weight as compared to control birds, respectively (p<0.05). A similar trend was observed for the percentage of the mentioned cuts. The right/total ventricular weight ratio (RV/TV) was significantly lower both in R7-21d and R14-28d treatments as compared to the control group. Blood constituents, such as glucose, cholesterol, and lactate dehydrogenase were also significantly altered by feeding regimes (p<0.05). The results of present study showed that R7-21d reduced ascites incidence, but had no significant effect on growth performance.
Abstract in English:This study compared three types of feeders for broilers: Fênix, Tube and Automatic feeders. Bird's feeding behavior and preference were considered in this the evaluation. Preference was assessed by examining birds' behavioral activities, such as eating, standing and lying around the equipments, and meal duration as function of the environmental variables. Data on the behavioral activities and meal size were collected in a broiler commercial farm using a portable video camera, and the direct footages were analyzed. The time spent in each activity, feeding bout duration and time spent near the trough were statistically analyzed using the test of means and medians. Pearson's correlation test was used to evaluate the relationship between ambient environmental data and the time of feeding. A prospective scenario was established and data were pair wised compared to it. There were interactions between environmental characteristics and feeding and lying down activities during the experiment. Eating behavior was more frequent in the area around the Tube feeder. The duration of feeding time was higher when the birds used the Tube feeder (214 ± 28s), followed by the use of the Fênix feeder (123 ± 17s) and the Automatic feeder (77 ± 29s). Birds preferred eating from the Tube feeder probably due to the absence of the partition grid above the feeder plate.
Abstract in English:Two experiments were carried out at the Poultry Sector of the School of Agrarian Sciences of the Federal University of Grande Dourados to evaluate the incidence of leg problems in broilers reared on two distinct types of bedding material: rice husks or wood shavings, both new and reused. In both trials, a randomized experimental design was applied in factorial arrangement (2 x 2 x 2) using two genetic strains (Cobb® or Ross®); two sexes (male or female), and two litter materials (rice husks or wood shavings). In each trial 1080 one day pullets were reared equally divided in the treatments. The birds were placed in 4.5 m² boxes at a density of 10 birds m-2. All birds were fed diets with equal nutritional density, and water was offered ad libitum. Feeds were divided in three phases: starter diet (1 - 21 days), grower diet (22 - 35 days), and finisher diet (36 - 45 days). On day 45, fifty birds were randomly selected in each experiment to evaluate flock leg problems. The following parameters were analyzed: gait score, incidence of valgus and varus disorder, footpad dermatitis, femoral degeneration, tibial dyschondroplasia, and spondylolisthesis. Ambient temperature during rearing and litter caking and moisture content were recorded in four boxes per treatment. The analytical hierarchy process was used to organize the data into specific criteria. Several criteria, related to the attributes that were determinant according to the statistical analysis, were chosen in order to provide the best input to the process. Results indicated that new wood-shavings bedding was the most appropriate bedding to prevent locomotion problems, followed by new rice husks, reused wood shavings, and reused rice husks. However, when leg problems were associated to sex and genetic strain, male Ross birds strain presented less problems when reared on new rice husks, followed by new wood shavings
Abstract in English:The infectious bronchitis virus (IBV) was detected for the first time in Brazil by Hipólito in 1957 in chickens sold life in the municipal market of Belo Horizonte, MG, when commercial poultry production was just starting in that country. The Massachusetts (Mass) serotype was identified. However, the clinical disease was only observed in 1975, when poultry production was intensely growing. The extensive outbreak produced the classical condition in layers and breeders, affecting egg production and quality, whereas broilers presented respiratory and "nephritis-nephrosis" signs. The disease rapidly spread to all poultry-producing regions in the country, and in 1979, both the imports and the manufacturing of live vaccines against IB strains Mass, H120 and H52, were licensed. In 1980, inactivated vaccines were introduced. Molecular techniques, particularly PCR, started to bed in the identification of IBV. A retrospective analysis showed that, up to 1989, the main IBV strain circulating in Brazil was Mass. However, other studies shows the presence of a wide diversity of IBV strains in Brazil since the first strains were isolated, even before vaccination was introduced. Most researchers agree that the incidence of IBV different from Mass has increased, including of exclusively Brazilian genotypes, different from those described in other countries. Indeed, during the last few years, the number of genotypical variants has been much higher than that of the classical Mass serotype. Clinically, in addition of the classic presentations, atypical forms such as testicular atrophy and stones in the epidydimis associated to low fertility have been described. Serological techniques started to be used in vaccination monitoring and as a diagnostic tool. Serological response standards were developed, and have shown to be very useful to determine the expected profile in vaccination programs and when clinical disease is suspected. However, the immuno-enzymatic test ELISA is the most frequently used around the world due to its convenience. These situations led service people working in the field to suspect that vaccination programs using Mass strains were not providing the required protection because of the presence of variant strains. Some argue that this was expected, particularly in layers and breeders, because Mass-type vaccines have been used for a long time, whereas most agree that the emergence of variants is the primary cause of the increasing severity of the disease in the field. This is supported by the results using Ibv genotyping as diagnostic tool, independently of phenotype (pathotype x immune system x environment). Other argues that broiler carcass downgrading rates in processing plant are not consistent with the increase in IB clinical severity. Seroconversion in non-vaccinated flocks is acknowledged, but it occurs sporadically and not necessarily correlated with disease outbreaks. There is a general agreement that IBV has shown high variability in Brazil in terms of genotype, pathotype, and serotype. However, research should emphasize IBV phenotypical characteristics using birds as biological model.
Abstract in English:A 30-day experiment involving 720 White Leghorn (L33) layer chickens of 39 weeks of age and average live weight of 1.8 ± 0.04 kg was carried out in a completely randomized design to evaluate the effects of vitamins C and E on erythrocyte parameters of layers during natural summer conditions. Birds were allotted to 4 treatments containing 0, 150 mg vitamin C, 150 mg vitamin E, and 150 mg vitamin C plus 150 mg vitamin E/kg feed. Each treatment was replicated four times. The exposure of layers to 31±3 °C and 33±0 °C ambient temperature and 84.6% and 81.5% relative humidity, inside and outside the experimental pen, during the study period caused an increase in temperature humidity index 15.5 above the threshold value of 70 established for this species. Total erythrocytes counts were not affected by treatment. However, hematocrit and hemoglobin were significantly (p<0.001) different in vitamin-C and E treated groups, individually or in combination, as compared to the control birds. Also, mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration of the birds fed vitamins C or E, or vitamins C+E were significantly (p<0.001) higher than those in control group. The results of the present study showed that the dietary supplementation of vitamin C and E, particularly as a combination, alleviated the counterproductive effects of high ambient temperature and humidity on the birds.