Abstract in English:In the poultry industry, the use of water with adequate physical, chemical and microbiological quality it is of fundamental importance. Since many birds have access to the same water source, quality problems will affect a great number of animals. The drinking water plays an important role in the transmission of some bacterial, viral and protozoan diseases that are among the most common poultry diseases. Important factors to prevent waterborne diseases in broiler production are the protection of supply sources, water disinfection and the quality control of microbiological, chemical and physical characteristics. Water is an essential nutrient for birds and therefore quality preservation is fundamental for good herd performance. The farmer may prevent many diseases in bird flocks by controlling the quality of the ingested water, will certainly result in decreased costs and increased profit, two essential aims of animal production nowadays.
Abstract in English:In the present study we have investigated the effects of heat acclimation on brain and hepatic Hsp70 protein levels and body temperature of broiler chickens in response to gradual heat stress. Two groups of broilers were raised up to 47 days of age under distinct temperature conditions: thermoneutral (TN, according to bird age) or hot environmental (HS, 31-33°C). At 46 days of age, the birds reared at high ambient temperature were transferred to thermoneutrality conditions. After 18 h, these birds and the birds reared at thermoneutral temperature were submitted to gradual heat stress in a climatic chamber so that environment temperature was increased from 28 to 40ºC at a rate of 2ºC/h. Colonic temperature was measured using a thermometer sensor probe at each two hours, and hepatic and brain tissues were collected immediately after slaughter in order to assess Hsp70 protein level by Western blotting analysis. The colonic temperatures of birds reared at high temperature increased steeply during the first 2 h of heat stress (1.06ºC/h) and more slowly thereafter (0.59ºC/h). Broilers reared at thermoneutral temperature showed a small increase in the first 4 h of heat stress (0.18ºC/h) and then colonic temperature increased sharply (0.72ºC/h). Nevertheless, both groups presented similar final colonic temperature by the end of the stress period. Hsp70 levels (ng Hsp70 µg total protein-1) did not change in the liver or brain of the birds reared at high temperature. On the other hand, both liver and brain Hsp70 levels increased significantly during heat stress in the animals reared at thermoneutrality, with a higher expression of this peptide in brain tissue.
Abstract in English:This study was carried out at Faculdade de Medicina Veterinária e Zootecnia, UNESP, Botucatu-SP, Brazil. The aim was to establish the normal values of bone mineral density (BMD) expressed in millimeters of aluminum in the tibia of broiler chickens using optical densitometry of radiographs. Four hundred Cobb male chicks were reared from 1 to 40 days of age, when 40 of them were selected and the right femur-tibia articulation was radiographed. Radiographs were taken with the X-ray equipment calibrated for 45 kvp and 3.2 mAs and a focus-to-film distance of 90 cm. An aluminum phantom ASTM-6063 consisting of 20 ladder steps with graduate density was placed parallel to the area to be radiographed and used as a densitometry reference standard. Radiograph images were analyzed using the software ATHENA - SIA. The proximal growth plate of the right tibia epiphysis was used as the standard reading region. The inclination axis of the reading window was 0 and the window was 10 mm high and 40-45 mm wide, depending on the bone size. Optical densitometry values of the radiographs ranged from 1.46 to 1.77 mmAl, and the coefficient of variation was 9.93%. It was concluded that densitometry values beyond the range established in the present study might indicate the presence of bone alteration in the tibia of broilers.
Abstract in English:Boron supplementation in broiler feed is not a routine practice. However, some reports suggest a positive effect of boron on performance. This study assessed the effects of boron supplementation on broiler performance. Diets were based on maize and soybean meal, using boric acid P.A. as boron source. Six supplementation levels (0, 30, 60, 90, 120 and 150 ppm) were evaluated using 1,440 one-day old males housed at a density of 30 chickens in each of 48 experimental plots of 3m². A completely randomized block design was used with 8 replicates. Feed intake, weight gain and feed conversion were assessed in the periods from 1 to 7 days, 1 to 21 days and 1 to 42 days of age, and viability was evaluated for the total 42-day rearing period. No performance variable was affected by boron supplementation (p>0.05) in the period from 1 to 7 days. The regression analysis indicated an ideal level of 37.4 ppm of boron for weight gain from 1 to 21 days (p<0.05) without affecting feed conversion (p>0.05), although feed intake was reduced linearly with increased boron levels (p<0.05). In the total rearing period (1 to 42 days), the level of 57 ppm boron was adequate for weight gain (p<0.01) without affecting feed conversion (p>0.05). Ash and calcium percentages in the tibias of broilers and viability in the total rearing period were not affected by boron supplementation (p>0.05).
Abstract in English:Two experiments were conducted to evaluate the effect of diets formulated using the criteria of crude protein (CP) and ideal protein (IP) on the yield and carcass composition of male and female broilers. Birds of two broilers strains (Hybro G and Hybro PG) were reared from 1 to 42 days of age during the summer, with average temperatures of 26°C. A completely randomized experimental design was used in a 2 x 2 factorial arrangement, with 6 replicates and 20 birds per pen. On day 42, four birds from each experimental unit were killed and carcass yield and composition were determined. Breast yield was higher in males and females fed the IP-based diet than in birds fed the CP-based diet. Abdominal fat pad and carcass crude protein were statistically similar between the two protein criteria and between strains. Carcass amino acid levels evidenced higher levels of Met, Lys, Met+Cys and Thr in the males fed IP-based diets. No differences were seen between the two criteria for the females. Diets formulated according to IP resulted in better carcass and breast yield, both for males and females.
Abstract in English:Seven hundred and twenty Ross 308 chicks were raised in a controlled environment room, distributed in a factorial design with 3 hatching chick weights (37, 40 and 44 g), 3 geometric mean diameter (GMD) (0.561; 0.783 and 0.997 mm) and 4 total sodium levels (Na) (0.12; 0.24; 0.36 and 0.48%) in the pre-starter diet (1 to 7 days). From 8 to 21 days (d) one single basal diet was used for all treatments. The thirty seven-gram chicks had the smallest yolk sack weight at 4d, smallest body weight (BW) and feed intake (FI) at 7d and 21d, but the same feed conversion (FC) than the other groups of hatching weight. Chicks receiving diet with intermediate GMD had the greatest BW and FI at 7d, but at 21d this effect was no longer seen. The diet with finest particle size resulted in birds with the smallest gizzard weight at 7d. The 0.12%Na diet was statistically different from the other Na levels, resulting in chicks at 7d with the worst FC and lowest body weights. At 21d, BW still was the lowest for this group of chicks. Birds with 0.48%Na produced more watery excreta and less dry matter in the carcass at 7d. Water consumption (C H2O) was influenced linearly by chick weight up to 0.36%Na level. In the 0.48%Na level, 40 and 44 g chicks had similar C H2O, which was different from 37-g chicks. For best performance, Na values were set from 0.31 to 0.48%. The three studied factors influenced quality of pre-starter diet and consequently chick performance.
Abstract in English:The present study evaluated the effect of different probiotics on the performance of broiler chickens. A thousand and fifty one-day-old male Cobb chicks were distributed in a completely randomized design in a 3 x 2 + 1 factorial arrangement (3 probiotics sources in the diet, 2 probiotics concentrations in drinking water and 1 control group), with 5 repetitions of 30 birds per parcel. The results showed better feed conversion (p<0.01) (1-21, 22-35 and 1-45 days) and weight gain (p<0.05) (22-35 and 1-45 days) in the control group in relation to the groups receiving probiotics. The use of Bacillus subtilis in the diet improved (p<0.05) feed conversion during the growing phase, but this was not seen in the following period. Thus, it was concluded that probiotics supplementation had no beneficial effects on the performance.
Abstract in English:The objective of this study was to evaluate the effect of different supplementation levels of Rhodocyclus gelatinosus biomass on the performance and pigmentation of broilers. Cobb broilers were raised in pens and were fed a sorghum-based diet until 35 days of age. At the 36th day of age, ninety-six birds were randomly distributed to four treatments consisting of experimental diets with different supplementation levels of Rhodocyclus gelatinosus biomass (0, 75, 150 and 300 ppm) added to the finisher basal diet, which were given for seven days. A completely randomized experimental design was used, with four treatments, four replicates and six broilers per parcel. Birds and diets were weighed at the 36th and at the 42nd day of age for performance analysis. There was no significant effect on broiler feed intake. Significant differences in weight gain and feed conversion were seen between the control group and the groups supplemented with 75 and 150 ppm. The treatment with the highest supplementation level and the control group had best weight gain and feed conversion. Color analysis showed that R. gelatinosus biomass supplementation resulted in more yellow breast skin and increased darkening and color purity in breast and thigh meat of broilers, but had no effect on lightness or color purity of breast and thigh skins.
Abstract in English:Infectious Bursal Disease (IBD) is a chicken disease economically important for the poultry industry in function of the immune depression that it causes. Disease control is made with different vaccines and vaccination programs. In present work, the pathogenicity of 3 intermediate vaccines (I1, I2 and I3), 2 intermediate more pathogenic (IP1 and IP2) and 3 vaccines containing strong virus (F1, F2 and F3) was evaluated. Birds vaccinated with IP1, IP2, F1, F2 and F3 showed significantly lower bursa size in relation to control animals and animals vaccinated with I1, I2 and I3. On the other hand, vaccines I1 and I3 induced antibody titers higher than the control and lower than I2, IP1, IP2, F1, F2 and F3. Histological scores showed that vaccines I1, I2 and I3 induced similar injury degree, although I2 and I3 were not different from the control, whereas I1 was slightly different. Strong vaccines induced more pronounced lesions than the other tested vaccines. These findings suggest that strong vaccines are able to cause severe bursal injuries. However, bursometry and relative weight of the bursa of Fabricius were considered inadequate to evaluate vaccine pathogenicity. Moreover, strong vaccines induced higher antibody titers than the other vaccines, although some intermediate vaccines induced similar titers.
Abstract in English:There are few reports concerning the epidemiology of Eimeria praecox and Eimeria mitis in Brazil. In the present experiment, the polymerase chain reaction (PCR) was used to identify these species in 156 samples of broiler chicken feces from several Brazilian states and the Federal District. Oocysts present in feces samples were purified by sodium chloride flotation followed by addition of DNAzol reagent (Invitrogen®) for extraction of genomic DNA. DNA was precipitated and stored following DNAzol reagent manufacture's instructions. The primers and PCR conditions were as described by Schnitzler et al. (1999). In the 156 field samples analyzed by PCR, 70 and 45 were positive for E. praecox and E. mitis, respectively. In this study we have shown that DNA extraction using DNAzol followed by PCR can be a useful tool in epidemiological studies, since it provides fast and reliable detection of Eimeria sp. in field samples.
Abstract in English:Avian Infectious Laryngotracheitis, caused by Infectious Laryngotracheitis Virus (ILTV), has been reported for decades in Brazilian laying and broiler flocks. More recently, outbreaks have occurred in São Paulo State. This study reports the application of PCR and DNA sequencing targeted to the p32 gene of ILTV using laying chicken samples from Bastos, São Paulo, Brazil. Three out of four field samples were positive by PCR. DNA sequencing of two samples evidenced homology of the amplified fragments with the p32 gene of ILTV. The results definitely confirmed the presence of ILTV in the birds during the outbreak. Further studies are needed to establish the sources of infection and to determine whether the detected virus was originated from vaccine or field virus strains.