Resumo em Inglês:

In this experiment, 240 Cobb-500® broilers reared from1 to 49 days, and distributed according to a completely experimental randomized design with four treatments of four replicates each in order to evaluate the effect of the dietary inclusion of 0, 33, 66 or 100 g/kg of squash seed meal (SSM) (Cucurbita moschata) on the performance, carcass yield, serum lipid profile and sensory meat quality of broilers. Significant differences (p<0.05) were detected in performance, carcass weight, weight and breast yield, and leg weight. The best results were obtained with 33 and 66 g/kg as compared to the control diet and 100 g SSM /kg. Abdominal fat decreased with the inclusion of 66 and 100 g SSM / kg, but the sensory quality of breast and thighs was not affected by the inclusion of SSM. The serum levels of total cholesterol, very low density (VLDL) and low density (LDL) lipoproteins, triglycerides, glucose and atherogenic index decreased with the inclusion of 100 g/kg of SSM, except for high density lipoproteins (HDL), which increased. The inclusion of 0, 33, 66 and 100 g/kg of SSM in broiler diets, partially replacing soybean meal and vegetable oil, improved live performance and edible portions yield. In addition, abdominal fat and serum levels of harmful lipids were reduced, whereas serum levels of beneficial lipids increased. There was no effect on meat sensory quality.

Resumo em Inglês:

The objective of this study was to evaluate the effect of corn texture and the particle size on broiler performance, carcass yield, nutrient digestibility, and digestive organ morphometrics. In Experiment I, 720 male Cobb chicks were distributed in a completely randomized experimental design with a 2 x 3 factorial arrangement, consisting two corn textures (dented and hard) and three corn particle sizes, was applied, with four replicates of 30 birds each. Corn particle size was classified according to geometric mean diameter (GMD) as fine - 0.46 mm; medium - 0.73 mm, and coarse - 0.87 mm. In Experiment II, 120 broiler chicks were used to evaluate corn digestibility during the periods of 16 to 22 days and 35 to 41 days of age, using the method of total excreta collection. In Experiment I, corn particle size influenced body weight, average weight gain, feed intake and feed conversion ratio of 21-day-old birds. Corn texture and particle size did not affect the performance of 42-day-old broilers or carcass traits. In Experiment II, there was no influence of corn texture and particle size on digestive organ weights. Dented corn increased nitrogen excretion in the first trial, and hard corn improved dry matter digestibility in the second metabolic trial. Corn with fine particle size promotes better performance of broilers at 21 days of age. Hard corn results in higher dry matter digestibility and lower nitrogen excretion, and consequently higher production factor in 42-day-old broilers.

Resumo em Inglês:

The aim of this study was to determine the effects of different levels of light intensity (0, 5 or 20 lx) and different pre-slaughter feed fasting duration (3, 6, 9, 12 and 15 hours) on the parameters body weight loss, carcass yield, commercial cuts yield, water carcass retention, bacterial counts and breast meat pH. A number of 72 broiler chickens at 45 days of age (Cobb 500 strain) was distributed in three chambers, in a total of 24 broilers per chamber. The results showed that feed fasting significantly influenced (p<0.05) body weight losswhen broilers were submitted to 9 hours of fasting. Broilers kept in the chamber with 0 lx presented higher body weight loss compared with other light intensities. The results showed an increase in carcass yield (p<0.05) as pre-slaughter feed fasting duration increased, but it did not affect commercial cuts yield or breast meat pH (p>0.05). The presence of feed in the crop and gizzard did not depend on light intensity, but was affected by pre-slaughter feed fasting duration. Bacterial counts decreased with feed fasting duration (p<0.05).

Resumo em Inglês:

This study aimed at evaluating the influence of genetic strain, sex, and season on the incidence of back scratches during the rearing period. Male and female broilers of two genetic strains reared during the hot or cold season were evaluated. This meta-analysis included 894 samplings in 351 broiler houses of contracted farms located in the state of Mato Grosso do Sul, Brazil, in 2010. Broilers of all ages (1 to 43 days) were sampled, capturing 2% of the birds in the house at each sampling. Each flock was evaluated twice, in 21-day intervals. Broilers were reared as single-sex flocks; there were no straight-run flocks. Scratch lesions were classified as present or absent. Strain A broilers presented lower scratch rates (p < 0.05) than strain B birds. During the starter period (1 a 21 days), males presented higher scratch rates (p < 0.05) than females, and the incidence of these lesions was lower during the hot season compared with the cold season. It was concluded that different management practices can be adopted to minimize back scratches in broilers of different sexes and strains during hot and cold seasons, such as reducing weight control frequency and the period of chick containment in brooder circles.

Resumo em Inglês:

We investigated the effects of crossbreeding on slaughter traits and the chemical composition of chicken breast muscle. Trials were conducted using 120 broilers from four lines: Xiao-Shan chicken (XS), Xian-Ju chicken (XJ), Xiao-Shan chicken♂♂ × Xian-Ju chicken♀♀ (Zhenan 1, ZNY1) and Xiao-Shan chicken♂♂ × (Guang-Xi Yellow chicken♂♂×Xian-Ju chicken♀♀) ♀♀ (Zhenan 2, ZNY2). The birds were slaughtered at 120 days of age and the slaughter traits were measured. Breast muscles were sampled to determine chemical composition. The slaughter traits of hybrid chickens were improved. Both hybrid strains had higher intramuscular fat (IMF) and inosine-5'-monophosphate (inosinic acid, IMP). Concentrations of monounsaturated fatty acids (MUFA) in breast muscles from the two hybrids were significantly higher than in the other two breeds (p < 0.05). The concentration of polyunsaturated fatty acids (PUFA) in the breast muscles of the two hybrids was significantly lower than in the other two breeds (p < 0.05). ZNY2 had significantly lower (p < 0.05) concentrations of myristic acid (C14:0). The breast muscle of ZNY1 had significantly higher palmitic acid (C16:0) concentrations than XS, XJ, or ZNY2 (p < 0.05). The concentrations of oleic acid (C18:1) and eicosapentaenoic acid (C20:5n-3, EPA) in breast muscle from the two hybrid lines were significantly higher than the other two breeds (p < 0.05). Breast muscles from XS and XJ chickens contained significantly higher docosahexenoic acid (C22:6n-3, DHA) than the two hybrid lines (p < 0.05). The XS and XJ chickens had lower n-6/n-3 ratios than the two hybrids (p < 0.05). Breast muscles from ZNY1 and ZNY2 contained higher concentrations of essential amino acids (p < 0.05), total amino acids (p < 0.05), and some individual amino acids (p < 0.05). In conclusion, crossbreeding improved the slaughter traits of chickens and increased intramuscular fat and inosinic acid content in breast muscle. The fatty acid and amino acid compositions of breast muscles were also improved by crossbreeding.

Resumo em Inglês:

The objective of the experiment was to determine the Apparent Metabolizable Energy corrected for nitrogen (AMEn) of a glycerin product derived from biodiesel production for broilers. A number of 35 male Ross 308 broilers, with 35 days of age was fed ad libitum diets containing 0, 5, 10, 15, or 20% glycerin. AMEn was determined using total excreta collection, with four days of adaptation and three days of collection. Increasing glycerin intakes resulted in increased water excretion. Glycerin AMEn varied as a function of dietary inclusion levels, and a cubic equation was identified by regression analysis. Maximum AMEn level- 4890 kcal/kg DM- was obtained with 15% glycerin inclusion. However, this level caused excessive water excretion, making its use unpractical.

Resumo em Inglês:

This study was conducted to determine the effect of the air temperature variation on the mean surface temperature (MST) of 7- to 35-day-old broiler chickens using infrared thermometry to estimate MST, and to study surface temperature variation of the wings, head, legs, back and comb as affected by air temperature and broiler age. One hundred Cobb® broilers were used in the experiment. Starting on day 7, 10 birds were weekly selected at random, housed in an environmental chamber and reared under three distinct temperatures (18, 25 and 32 ºC) to record their thermal profile using an infrared thermal camera. The recorded images were processed to estimate MST by selecting the whole area of the bird within the picture and comparing it with the values obtained using selected equations in literature, and to record the surface temperatures of the body parts. The MST estimated by infrared images were not statistically different (p > 0.05) from the values obtained by the equations. MST values significantly increased (p < 0.05) when the air temperature increased, but were not affected by bird age. However, age influenced the difference between MST and air temperature, which was highest on day 14. The technique of infrared thermal image analysis was useful to estimate the mean surface temperature of broiler chickens.

Resumo em Inglês:

Gas production in broiler houses and their emissions are closely related to the microclimate established inside the house according to air temperature, humidity, and velocity. Therefore, the internal house environment is influenced by building typology and ventilation system. The objective of the present study was to evaluate ammonia emission rates in broiler houses equipped with different ventilation systems (negative or positive pressure) and litter conditions (new or built-up). The environment of six commercial broiler houses was evaluated internal and external NH3 concentrations. Ventilation rates were recorded to estimate ammonia emission rates. The efficiency of circulation and exhaust fans was assessed, and higher ventilation rates were determined in negative-pressure houses due to the higher flow of the fans. Houses with new litter increased ammonia emission rates along the rearing period, indicating the relationship between gas emissions, bird age and ventilation rates, and presented a typical curve of NH3 emission increase. Negative-pressure houses with built-up litter presented higher emission rates during the first rearing week due to the high NH3 concentration during the brooding period, when the ventilation rates required to maintain chick thermal comfort are low. Although the results of the present study indicate an advantage of the positive-pressure systems as to gas emissions, further research is needed reduce gas emissions in broiler houses with negative-pressure systems.

Resumo em Inglês:

The objective of this study was to determine the economic efficiency of resource utilization in broiler production farms using a non-parametric production function, data envelopment analysis (DEA). Data for the analysis were collected from a cross section of 44 farmers using a multi-stage sampling procedure. In DEA models the farmers that produce their level of output with the least amount of input serve as benchmarks against which the input use inefficiency of all other farmers can be measured. The total variable costs, net return and benefit cost ratio were calculated to be 3506.29 $ (1000 bird)-1, 1386.53 $ (1000 bird) -1 and 1.38, respectively. The average values of technical and scale efficiencies of farmers were found to be 0.92 and 0.93. The results also revealed that about 10% of the total input resources could be saved if the farmers follow the input package recommended by the DEA.

Resumo em Inglês:

There is no formal recommendation, regarding dietary concentration, when it comes to feeding distillers dried grains with solubles (DDGS) to young broilers. This study evaluated the effects of varying levels of DDGS in a diet to young broilers from 0 to 14d of age. Diets ranged from 0 to 32% DDGS concentration, with 8% increments. Increasing inclusion rate of DDGS led to decreased body weight gain (BWG), whereas mortality seemed to be linearly increased. However, there was an increase seen in feed conversion (FCR) in conjunction with the increase in DDGS in the diet. An inclusion level of 8% DDGS or less is recommended for starter diets for broiler chicks.

Resumo em Inglês:

Two experiments were carried out to determine which factor influences weight at hatch of broiler chicks: breeder age or incubated egg weight. In Experiment 1, 2340 eggs produced by 29- and 55-week-old Ross® broiler breeders were incubated. The eggs selected for incubation weighed one standard deviation below and above average egg weight. In Experiment 2, 2160 eggs weighing 62 g produced by breeders of both ages were incubated. In both experiments, 50 additional eggs within the weight interval determined for each breeder age were weighed, broken, and their components were separated and weighed. At hatch, hatchlings were sexed and weighed, determining the average initial weight of the progeny of each breeder age. Data were analyzed using the Analyst program of SAS® software package. In Experiment 1, the weight difference between eggs produced by young and mature breeders was 10.92 g, and the component that mostly influenced this difference was the yolk (7.51 g heavier in mature breeders, compared with 4.23 g difference in albumen and 0.8 g in eggshell weights). Hatchling weight difference was 9.4 g higher in eggs from mature breeders. In Experiment 2, egg weight difference was only 0.74 g, but yolk weight was 4.59 g higher in the eggs of mature breeders. The results obtained in the present study indicate that hatchling weight is influenced by egg weight, and not by breeder age.