Broilers'toes asymmetry and walking ability assessment

Brazilian poultry production nowadays occupies important position in world's economy due to its technological advancement, which associated to the development of genetic strains of high growth may cause deviation in the growth rate and harm production. Morphological asymmetry has been pointed as an indicator of welfare, as maintained the pattern that leads to balance, the broiler chicken would have its normal locomotion characteristics, freely reaching water and feed. Thus, the objective of this research was to verify the possibility of using morphological asymmetry for evaluating walking ability of broiler chicken. The research was done in the Technology Center, at UNICAMP. The experiment was made using biomechanics analysis and following, the toes were measured. Results found did not show asymmetry useful for determining the locomotion ability of broiler chicken. New studies are recommended in order to search for other correlations that might help to estimate at field level, the locomotion difficulties of broiler chicken.

Adjust of regression models to estimate the rectal temperature of broilers for the first 14 days of life

The broiler rectal temperature (t rectal) is one of the most important physiological responses to classify the animal thermal comfort. Therefore, the aim of this study was to adjust regression models in order to predict the rectal temperature (t rectal) of broiler chickens under different thermal conditions based on age (A) and a meteorological variable (air temperature - t air) or a thermal comfort index (temperature and humidity index -THI or black globe humidity index - BGHI) or a physical quantity enthalpy (H). In addition, through the inversion of these models and the expected t rectal intervals for each age, the comfort limits of t air, THI, BGHI and H for the chicks in the heating phase were determined, aiding in the validation of the equations and the preliminary limits for H. The experimental data used to adjust the mathematical models were collected in two commercial poultry farms, with Cobb chicks, from 1 to 14 days of age. It was possible to predict the t rectal of conditions from the expected t rectal and determine the lower and superior comfort thresholds of broilers satisfactorily by applying the four models adjusted; as well as to invert the models for prediction of the environmental H for the chicks first 14 days of life.

Using data mining to identify factors that influence the degree of leg injuries in broilers

Locomotor problems prevent the bird to move freely, jeopardizing the welfare and productivity, besides generating injuries on the legs of chickens. The objective of this study was to evaluate the influence of age, use of vitamin D, the asymmetry of limbs and gait score, the degree of leg injuries in broilers, using data mining. The analysis was performed on a data set obtained from a field experiment in which it was used two groups of birds with 30 birds each, a control group and one treated with vitamin D. It was evaluated the gait score, the asymmetry between the right and left toes, and the degree of leg injuries. The Weka ® software was used in data mining. In particular, C4.5 algorithm (also known as J48 in Weka environment) was used for the generation of a decision tree. The results showed that age is the factor that most influences the degree of leg injuries and that the data from assessments of gait score were not reliable to estimate leg weakness in broilers.

Thermal comfort in reduced models of broilers' houses, under different types of roofing materials

The research was developed to evaluate the use of different types of roofing materials regularly used in poultry houses. Measurements of thermal comfort were made through the use of techniques such as the Black Globe and Humidity Index (BGHI), the Thermal Heat Load (THL) and Enthalpy (H). Conducted in the State University of Goiás, during the months of April and May, 2011, the experiment was composed of five different treatments: AC - Asbestos cement tiles, BA -Bamboo tiles, BAP - Bamboo tiles painted in white, FB -Vegetable fiber tiles and bitumen, FBP -Vegetable fiber tiles and bitumen painted in white. The experiment consisted in 15 repetitions, which were considered the different days of measurements taken. Throughout the studied period, the time of the day considered the least comfortable was the one observed at 2:00pm, and the coverage of vegetable fiber and bitumen showed the highest value of BGHI (84.1) when compared to other types of coverage, characterizing a situation of lower thermal comfort, and no difference was found for THL and H on treatments in the studied region.

Evaluation of the heating of broilers in shed by means of gas hoods and underfloor heating

This study was conducted to evaluate and compare the behavior of the heating inside poultry shed through gas hood and underfloor heating. The experiment was conducted in poultry shed belonging to the Federal Institute of Education, Science and Technology of Triângulo Mineiro Region, Uberlândia city – state of Minas Gerais (MG), Brazil. The dimensions of the shed are 24 meters long and 9.6 meters wide and with a ceiling height of 3.2 meters. The temperature was measured with an optical thermometer of Minipa brand, MT 350 model. It was used, to the analysis of temperature behavior, the public domain software FEMM 4.2, which uses finite elements techniques, with data collected from two lots. Underfloor heating is made using hot water flowing through a serpentine type system, which is installed below the bed; this hot water is from solar heaters. An energetic and economic assessment of the warming shed for raising chickens was realized. From the results obtained with the simulations, it may observe that the heating through the floor provides a more homogeneous distribution of temperature when compared with the hood heating. The flow of heat is upwards supplying, thus, the greatest need of heating of the bird, which is the pectoral part.

Transport of broilers: load microclimate during Brazilian summer

The objective of this study was to characterize the microclimatic profile of broiler transport trucks under commercial conditions, in the summer, by continuous monitoring of environmental variables (temperature and air relative humidity). Three loads were monitored from farm to slaughterhouse, considering factors such as distance and day periods (morning, afternoon, and night). To obtain the profile of the environmental variables during journey, data loggers, that determined the microclimate to which birds were submitted, were installed in the trucks; data loggers also allowed visualization of the Enthalpy Comfort Index (ECI) so that load regions could be classified according to heat comfort limits for 6-week old poultries. Temperature, relative humidity, and ECI in the truck were analyzed, using geostatistics, by the ordinary kriging method. The afternoon was the most critical period, and truck central and rear regions were most problematic for chickens, thus most susceptible to losses.

Vocalization of broilers can be used to identify their sex and genetic strain

In order to reach higher broiler performance, farmers target losses reduction. One way to make this possible is by rearing sexed broilers as male and female present diverse performance due to their physiological differences. Birds from different genetic strain also have a distinct performance at the same age. Considering that sexed flocks may present higher performance this study aimed to identify one-day-old chicks’ sex throughout their vocalization. This research also investigated the possibility of identifying the genetic strain by their vocalization attributes. A total of 120 chicks, half of them were from Cobb® genetic strain and the other half from Ross® genetic strain. From each group, a total of 30 were males and 30 females, which were previously separated by sex using their secondary physiological characteristics at the hatchery. Vocalizations audio recording was done inside a semi-anechoic chamber using a unidirectional microphone connected to an audio input of a digital recorder. Vocalizations were recorded for two minutes. Acoustic characteristics of the sounds were analyzed being calculated the fundamental frequency Pitch, the sound intensity, the first formant, and second formant. Results indicated that the vocalizations of both sexes could be identified by the second formant, and the genetic strain was detected by both the second formant and the Pitch.

The use of infrared thermography in the identification of pododermatitis in broilers

ABSTRACT International trade in broiler’ feet, mainly to Asian markets, has demanded better quality control. The objective of this research was to study the suitability of using chicken footpad surface temperature to determine early lesions of pododermatitis. The project was conducted in two houses A1 and A2) in a commercial farm during one production flock. A1 had reused litter of wood shavings and rice hulls, and A2 had a new litter of sawdust. Both houses had positive pressure ventilation. The inner area of the poultry was virtually divided into three quadrants. The footpads were checked for the feet quality, and a degree of pododermatitis was awarded. Thermal images were made to test the surface temperature of the foot and identify inflammation in a total of 30 birds per house, at ages 5, 19, 29, 28 and 40 days of grow-out. Conditions of the rearing environment as well as the surface temperature of the litter, litter moisture, and degree of compression, were recorded. The environment within the houses did not differ. The surface temperatures of the footpad did not differ between the groups. The minimum footpad surface temperatures within the scores were similar, except for the score 3, which did not occur in A1. There was a prevalence of severe injury in the house with a new litter.

Brazilian avian metapneumovirus subtypes A and B: experimental infection of broilers and evaluation of vaccine efficacy

Avian metapneumovirus (aMPV) is a respiratory pathogen associated with the swollen head syndrome (SHS) in chickens. In Brazil, live aMPV vaccines are currently used, but subtypes A and, mainly subtype B (aMPV/A and aMPV/B) are still circulating. This study was conducted to characterize two Brazilian aMPV isolates (A and B subtypes) of chicken origin. A challenge trial to explore the replication ability of the Brazilian subtypes A and B in chickens was performed. Subsequently, virological protection provided from an aMPV/B vaccine against the same isolates was analyzed. Upon challenge experiment, it was shown by virus isolation and real time PCR that aMPV/B could be detected longer and in higher amounts than aMPV/A. For the protection study, 18 one-day-old chicks were vaccinated and challenged at 21 days of age. Using virus isolation and real time PCR, no aMPV/A was detected in the vaccinated chickens, whereas one vaccinated chicken challenged with the aMPV/B isolate was positive. The results showed that aMPV/B vaccine provided a complete heterologous virological protection, although homologous protection was not complete in one chicken. Although only one aMPV/B positive chicken was detected after homologous vaccination, replication in vaccinated animals might allow the emergence of escape mutants.

Classification of antimicrobial resistance using artificial neural networks and the relationship of 38 genes associated with the virulence of Escherichia coli isolates from broilers

Avian pathogenic Escherichia coli (APEC) is responsible for various pathological processes in birds and is considered as one of the principal causes of morbidity and mortality, associated with economic losses to the poultry industry. The objective of this study was to demonstrate that it is possible to predict antimicrobial resistance of 256 samples (APEC) using 38 different genes responsible for virulence factors, through a computer program of artificial neural networks (ANNs). A second target was to find the relationship between (PI) pathogenicity index and resistance to 14 antibiotics by statistical analysis. The results showed that the RNAs were able to make the correct classification of the behavior of APEC samples with a range from 74.22 to 98.44%, and make it possible to predict antimicrobial resistance. The statistical analysis to assess the relationship between the pathogenic index (PI) and resistance against 14 antibiotics showed that these variables are independent, i.e. peaks in PI can happen without changing the antimicrobial resistance, or the opposite, changing the antimicrobial resistance without a change in PI.

Detection of transgenic and endogenous plant DNA fragments in the blood, tissues, and digesta of broilers

The aim was to determine the fate of transgenic and endogenous plant DNA fragments in the blood, tissues, and digesta of broilers. Male broiler chicks (n = 24) were allocated at 1 day old to each of four treatment diets designated T1-T4. T1 and T2 contained the near isogenic nongenetically modified (GM) maize grain, whereas T3 and T4 contained GM maize grain [cry1a(b) gene]; T1 and T3 also contained the near isogenic non-GM soybean meal, whereas T2 and T4 contained GM soybean meal (cp4epsps gene). Four days prior to slaughter at 39-42 days old, 50% of the broilers on T2-T4 had the source(s) of GM ingredients replaced by their non-GM counterparts. Detection of specific DNA sequences in feed, tissue, and digesta samples was completed by polymerase chain reaction analysis. Seven primer pairs were used to amplify fragments (similar to 200 bp) from single copy genes (maize high mobility protein, soya lectin, and transgenes in the GM feeds) and multicopy genes (poultry mitochondrial cytochrome b, maize, and soya rubisco). There was no effect of treatment on the measured growth performance parameters. Except for a single detection of lectin (nontransgenic single copy gene; unsubstantiated) in the extracted DNA from one bursa tissue sample, there was no positive detection of any endogenous or transgenic single copy genes in either blood or tissue DNA samples. However, the multicopy rubisco gene was detected in a proportion of samples from all tissue types (23% of total across all tissues studied) and in low numbers in blood. Feed-derived DNA was found to survive complete degradation up to the large intestine. Transgenic DNA was detected in gizzard digesta but not in intestinal digesta 96 h after the last feeding of treatment diets containing a source of GM maize and/or soybean meal.

A comparative evaluation of functions for partitioning nitrogen and amino acid intake between maintenance and growth in broilers

The results from three types of study with broilers, namely nitrogen (N) balance, bioassays and growth experiments, provided the data used herein. Sets of data on N balance and protein accretion (bioassay studies) were used to assess the ability of the monomolecular equation to describe the relationship between (i) N balance and amino acid (AA) intake and (ii) protein accretion and AA intake. The model estimated the levels of isoleucine, lysine, valine, threonine, methionine, total sulphur AAs and tryptophan resulting in zero balance to be 58, 59, 80, 96, 23, 85 and 32 mg/kg live weight (LW)/day, respectively. These estimates show good agreement with those obtained in previous studies. For the growth experiments, four models, specifically re-parameterized for analysing energy balance data, were evaluated for their ability to determine crude protein (CP) intake at maintenance and efficiency of utilization of CP intake for producing gain. They were: a straight line, two equations representing diminishing returns behaviour (monomolecular and rectangular hyperbola) and one equation describing smooth sigmoidal behaviour with a fixed point of inflexion (Gompertz). The estimates of CP requirement for maintenance and efficiency of utilization of CP intake for producing gain varied from 5.4 to 5.9 g/kg LW/day and 0.60 to 0.76, respectively, depending on the models.

A comparative evaluation of functions for the analysis of growth in male broilers

Data from six studies with male broilers fed diets covering a wide range of energy and protein were used in the current two analyses. In the first analysis, five models, specifically re-parameterized for analysing energy balance data, were evaluated for their ability to determine metabolizable energy intake at maintenance and efficiency of utilization of metabolizable energy intake for producing gain. In addition to the straight line, two types of functional form were used. They were forms describing (i) diminishing returns behaviour (monomolecular and rectangular hyperbola) and (ii) sigmoidal behaviour with a fixed point of inflection (Gompertz and logistic). These models determined metabolizable energy requirement for maintenance to be in the range 437-573 kJ/kg of body weight/day depending on the model. The values determined for average net energy requirement for body weight gain varied from 7(.)9 to 11(.)2 kJ/g of body weight. These values show good agreement with previous studies. In the second analysis, three types of function were assessed as candidates for describing the relationship between body weight and cumulative metabolizable energy intake. The functions used were: (a) monomolecular (diminishing returns behaviour), (b) Gompertz (smooth sigmoidal behaviour with a fixed point of inflection) and (c) Lopez, France and Richards (diminishing returns and sigmoidal behaviour with a variable point of inflection). The results of this analysis demonstrated that equations capable of mimicking the law of diminishing returns describe accurately the relationship between body weight and cumulative metabolizable energy intake in broilers.