163 resultados para Laying


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The objectives of the present study were: to evaluate the variation in total number of microorganisms in laying hen fecal samples and to identify the pathogenic microorganisms possibly present such as Staphylococcus aureus, Salmonella sp., Clostridium botulinum, C chauvoei, Campylobacter sp., Escherichia coli, and Corynebacterium sp. The experiment was conducted at the School of Agrarian and Veterinarian Sciences of Jaboticabal, - UNESP. Fecal samples were collected from the aviary. A fully randomized experimental design was used with 7 treatments and 4 replications, for a total of 28 samples. A decrease in total number of microorganisms was detected when treatment T0 (zero days of storage) was compared with treatment T6 (42 days of storage), with oscillations in numbers being observed during this period of time. Pathogenic bacteria such as Clostridium noyvi, C perfringens, C sordelli, C septicum and C noyvi type B were detected, as well as non-pathogenic bacteria such as Bacillus sp. and Staphylococcus epidermidis.

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This research was carried out to verify the ability of laying hens to select food in order to meet their requirements for protein and energy. Ninety-six Hy-Line White laying hens, 45 weeks old, were allotted to a randomized block design with two blocks (two ranges of body weight), four treatments, and three replicates of four hens in each block. The treatments consisted of four different feeding systems: I-Conventional feeding represented by a complete ration composed of 60% ground corn and 40% protein concentrate; 2-Free-choice feeding with ground corn, protein concentrate and oyster shells fed in feeders with three separate compartments; 3-Semi free-choice feeding with whole corn grain, protein concentrate and oyster shells in the same proportion in one feeder; 4-Free-choice feeding with whole corn grain, protein concentrate and oyster shells fed in feeders with three separate compartments. The results indicated that the hens, in spite of age, adapt to different feeding systems, and that they can select feed to meet their nutrient requirements. The semi free-choice and free-choice feeding systems with whole corn grain resulted in the same performance compared to conventional feeding, but shell quality was not improved by oyster shell supplementation. However, the worst performance was with free-choice feeding with ground corn, which indicated that in the free-choice feeding system the use of whole corn grain is recommended.

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An experiment with 400 laying hens Hy Line with 26 weeks of age was conducted to compare the performance of laying hens fed during four cycles of 28 days with diets containing soybean meal (SM) plus soybean oil (SBM+oil), whole extruded soybean (ESB) and whole steam toasted soybean (TSB). A completely design randomized blocks was used, with 10 treatments and five replicates and eight laying hens in each experimental unit. The treatments consisted on the replacement of SBM per ESB and TSB at the levels 0, 25, 50, 75 and 100%; and as control the SBM with or without addition of oil. The results obtained showed that the hens were able to regulate the feed intake to maintain the energy intake only at lower energetic levels, however they tended to over intake energy with the increase of energy levels of the diets. The addition of oil or soybeans in the diets improved feed: gain ratio, however worsened the energy efficiency in relation to the diet without oil. The processing of soybean provided differences on the performance of laying hens and the ESB showed to be superior to TSB. The hens had higher use of the oil added to the soybean meal (SBM + oil) and ESB in relation to TSB. However, the values of AMEn obtained for the ESB were 12% higher, in average, to those determined for the SBM + oil and for the TSB.

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In intubation experiments (643-1168 mg per animal), most of the stevioside administered to chickens was recovered unchanged in the excreta, and only about 2% was converted into steviol. Neither stevioside nor steviol could be found in the blood. In chronic studies (667 mg of stevioside/kg of feed) with laying hens and meat-type chickens, no significant differences were found in feed uptake, weight gain, and feed conversion as the result of stevioside administration. The egg production and egg composition of laying hens were not influenced. Most of the stevioside taken up was found untransformed in the excreta, and about 21.5% or 7.3% was converted to steviol by meat-type chickens or laying hens, respectively. No stevioside or steviol could be detected in the blood or in the eggs of the different groups of animals. In anaerobic incubation experiments with chicken excreta, only a 20% conversion of stevioside into steviol was found. No harmful effects were observed in the chronic stevioside supplementation experiments nor in the intubation experiments in which very high stevioside doses were given.

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The serological response to Salmonella pullorum and S. gallinarum infection in chickens was studied with an indirect enzyme-linked immunosorbent assay (ELISA). In broiler chickens, a more virulent strain of S. pullorum produced a significantly lower serum IgG titer than did a less virulent strain. In laying hens, the serum and egg-yolk IgG titers were very similar. In chickens infected with S. gallinarum, high IgG titers persisted for 30 weeks. In chickens reinfected with this strain, each reinfection was followed by transitory increases in IgG lasting no longer than 2 weeks. Serum samples from Brazil taken from a laying flock with evidence of fowl typhoid showed much higher antibody levels than did those from three uninfected flocks. Using lipopolysaccharide as the detecting antigen, infections caused by these salmonellae could be differentiated from those caused by other groups. Incorporation of the appropriate flagella antigen in the ELISA allowed differentiation between infections caused by S. pullorum and S. enteritidis.

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Biomass of the photosynthetic bacterium Rhodocyclus gelatinosus was used at different levels in laying hens' rations as a xanthophyll source. Sixty-four hens were used in the experiment that investigated the effects of different biomass concentrations on weight gain, egg production, egg weight, and yolk color as compared with a control group that received no biomass supplementation in the ration. Yolk color was scored by means of a color fan. All concentrations tested were able to provide yolk color scores higher than those provided by the control group. The pigment deposition began after 24 h of administration and reached a plateau around the twentieth day. Each increase in the supplementation level led to an additional increase on yolk color scores. Yolk colors of all treatments that received R. gelatinosus biomass differed significantly from the control group and from each other, corroborating that the increase in the biomass supplementation had a positive effect on color increase. Body weight loss occurred in all treatments. Egg production did not increase with the biomass addition, while a significant increase in egg weight was observed in the treatments that received the product.

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In this trial the bromatologic composition of caged laying hen manure was studied according to a completely randomized design with four treatments and six replications. The treatments T-1, T-2, T-3 and T-4 consisted of caged laying hen manure stocked for 0; 7; 14 and 21-day times, respectively. Stocking period until 21 days decreased crude protein (P<0.01) and gross energy (P<0.01). The best bromatologic composition of hen caged manure data were proportional to the lower stocking time.

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Laboratory animals exposed to feeding ticks develop resistance which is reflected by a decline in tick engorgement weight, egg-laying by adults and reduced egg viability. Serum antibodies from these hosts and their reaction with tick antigens have been detected by different methods, including precipitation techniques, immunofluorescent techniques, ELISA and Western blots. However, little is known about the effects of antibodies on ticks that engorge on resistant hosts, or which tissues of the tick body are possibly immunogenic. Some researchers, using immunohistochemistry, have detected host antibodies in the gut, salivary glands and haemolymph of ticks engorged on resistant animals. The same technique has helped considerably in determining antigenic sites or antibody targets in other arthropods. Consequently, immunohistochemistry techniques were used in this study to detect cross-reactivity between sera raised against Amblyomma cajennense (Fabricius, 1787) with Amblyomma hebraeum (Koch, 1844), and vice versa. The results show the existence of shared antigens between the 2 tick species. In general, our results point more to a 1-way cross-reactivity of A. hebraeum with A. cajennense than a reciprocal cross-reactivity, suggesting that A. hebraeum is more immunogenic than A. cajennense.

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A research about arthropode fauna in laying hen excrement was carried out in a poultry house in the State of São Paulo, from January 2001 to December 2002. The objective was to verify the frequency of Diptera and Coleoptera collected by Berlese funil and flutuation methods, and to show correlation between the collect methods and sazonality possible in the currents seasons. A total of 29,499 insects were collected from seventy five collects, being 16,702 Diptera (six families) and 12,797 Coleoptera (four families). Some arthropodes presented direct relation with the collect method, the seasons of the years and the rainfall precipitation, with significant increase in the number of insects collected in certain periods of the year.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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This study was carried out to evaluate the performance and egg quality of laying hens, in their second laying cycle submitted to different forced-molting methods and three environmental temperatures. Six hundred layers were distributed in a completely randomized experimental design with 15 treatments with five replicates of eight birds each, according to 5x3 factorial arrangement (molting methods vs. temperatures). The following forced-molting methods were applied: 90%, 70%, 50% dietary alfalfa inclusion, addition of 2,800 ppm zinc, and feed fasting. Temperatures were: 20 degrees C, 27 degrees C and 35 degrees C. At the end of each period of the second laying cycle, bird performance and egg quality were evaluated. Data were submitted to analysis of variance and means were compared by orthogonal and polynomial contrasts. The highest alfalfa inclusion level (90% alfalfa and 10% basal diet) proved to be efficient as compared to the other methods, independently of temperature.