Abstract in English:The use of probiotics in animal and human feeding has been a subject of increasing interest both for the academia and the industry, mostly due to their potential positive effects on health and profitability. However, the knowledge on the composition of bacterial gastrointestinal communities in humans and animals, as well as its respective nutritional requirements, is far from being elucidated. Due to the ban of the use of antibiotic growth promoters in animal feeds, there has been an increasing interest on the utilization of probiotics to improve animal intestinal health under commercial settings. However, the possibility of horizontal transference of antibiotic-resistant genes between probiotic bacteria and pathogenic species has become a concern of poultry farmers and consumers around the world. Innovative ideas have emerged, such as the addition of essential oils, spices, and other plant extracts to feeds of monogastric animals to promote intestinal health. These natural compounds are considered ecologically adequate and safe for feeding purposes. This new reality will probably change the direction of research and of the use of additives in poultry production.
Abstract in English:This study aimed at evaluating the effects of trace mineral levels and sources supplemented to diets fed to semi-heavy layers in their second laying cycle on the quality of eggs stored for 14 days at different temperatures. The experimental diets consisted of the inclusion of inorganic trace minerals (T1 - control: 100% ITM) and five supplementation levels of organic trace minerals (carboaminophopho chelates) (110, 100, 90, 80, and 70% OTM). Trace mineral inclusion levels (mg/kg feed) were: T1: control - 100% ITM: Zn (54), Fe (54), Mn (72), Cu (10), I (0.61) Se (0.3); T2 - 110% OTM: Zn (59.4), Fe (59.4), Mn (79.2), Cu (11.88), I (1.21) Se (0.59); T3 - 100%: OTM: Zn (54), Fe (54), Mn (72), Cu (10.8), I (1.10) Se (0.54); T4 - 90% OTM: Zn (48.6), Fe (48.6), Mn (64.8), Cu (9.72), I (0.99) Se (0.49); T5 - 80% OTM: Zn (43.2), Fe (43.2), Mn (57.6), Cu (8.64), I (0.88), Se (0.43); T6 - 70% OTM: Zn (37.8), Fe (37.8), Mn (50.4), Cu (7.56), I (0.77) Se (0.38). A completely randomized experimental design in a split-plot arrangement with 60 treatments of four replicates each was applied. The combination of six diets versus storage temperature (room or under refrigeration) was randomized in plots, whereas the sub-plots consisted of storage times (0, 3, 7, 10, and 14 days). Data were submitted to analysis of variance of a model in slip-plots in time using the software package SAS (2000) at 5% probability level. It was concluded that 70% OTM supplementation can be used with no damage to egg quality, independently from storage temperature or time. The quality of refrigerated eggs stored up to 14 days is better than those stored at room temperature.
Abstract in English:It is known that PSE meat present important functional defects, such as low water holding capacity and ultimate pH, which may compromise the quality of further-processed meat products. In this study, L* (lightness), a* (redness), and b* (yellowness) values of 500 chicken breast fillets were determined using a portable colorimeter (Minolta, model CR-400) in a commercial processing plant. Fillets were considered pale when their L* was >49. Out of those samples, 30 fillets with normal color and 30 pale fillets were evaluated as to pH, drip loss, cooking loss, water holding capacity, shear force, and submitted to sensorial analysis. An incidence of 10.20% PSE meat was determined. Pale and normal fillets presented significantly different (p<0.05) pH values, L* and a* values, water holding capacity, drip loss, and cooking loss, demonstrating changes in the physical properties of PSE meat. Shear force and sensorial characteristics were not different (p>0.05) between pale and normal fillets. Despite the significant differences in meat physical properties, these were not perceived by consumers in terms of tenderness, aspect, and flavor. The observed incidence of PSE may cause losses due to its low water retention capacity.
Abstract in English:To clarify the effects of high (20 and 40% more than normal) and low (20% less than normal) daily feed allowance on egg and body parameters, ovarian morphology and plasma glucose, cholesterol, triacylglycerol, leptin-like hormone, nitrite/nitrate and gene expression of inducible nitric oxide synthase (iNOS) in the granulosa layer of F1 follicle, broiler breeder hens (30-week-old) were fed for 30 days. Egg and body parameters significantly changed between treatments (p<0.05). Effect of different level of feed intake on ovarian morphology parameters was significant (p<0.05), except for white follicles. After 30 days of experiment, plasma nitrite/nitrate (as a index of plasma nitric oxide) and leptin-like hormone increased in FI+20% and FI+40% groups as compared to controls (p<0.05). Plasma level of leptin-like hormone also significantly (p<0.05) increased in FI+40% group. The relative amount of iNOS mRNA expression in the granulosa layer of F1 follicles was significantly higher in FI-20% and FI+40% groups than in control group only after 4 weeks of experiment. The amount of these elevations in the FI-20% and FI+40% groups were 32.4% and 60.9% respectively. It was concluded that iNOS gene is normally expressed in follicular granulosa cells of F1 follicle of broiler breeder hens 2-4 hours before ovulation. However, over- and underfeeding of hens increased iNOS expression in F1 follicle, which may be one of the atresia-inducing factors in hierarchical follicles as shown by the significant (p<0.05) increase of shrunken follicles in the ovary of over- and under-fed broiler breeder hens after 30 days of feeding.
Abstract in English:One to 42-d-old (432) female broilers were fed different levels of inorganic selenium (ISe) and organic selenium (OSe), according to the following treatments: (1) 0.3 mg ISe; (2) 0.3 mg ISe + 0.2 mg OSe; (3) 0.5 mg ISe and (4) 0.3 mg OSe/ kg of feed. All birds were vaccinated against infectious bursal disease (IBD) at 19d of age and three birds/replicate (R) were inoculated with sheep red blood cells (SRBC) at 32d. Three other birds/R received Freund's adjuvant at 37d and avian tuberculin (AT) in the wattle at 47d of age. All birds were submitted to heat stress after 21d. Performance parameters, bursa and spleen weights, lymphocyte bursa depletion, antibody (Ab) production against IBD and SRBC, hematocrit, leukocytes, heterophil/lymphocyte ratio (H/L), and cellular reaction to AT were evaluated. The contrast analysis showed that OSe has improved feed intake (FI) between day 1 and 42 (p<0.10). Birds fed ISe presented worse H/L ratio (p<0.10), but higher Ab titers against IBD (p<0.04) and SRBC (p<0.05) than birds fed OSe, but OSe supplemented birds showed lower lymphocyte depletion scores in the bursa. The higher FI promoted by OSe may be beneficial when rearing broilers in hot weather. The use of ISe induced higher humoral immune response
Abstract in English:This study aimed at determining a specific classification of coefficients of variation in experiments with commercial layers. Coefficients of variation were collected from papers published in Brazilian journals between 2000 and 2009 for performance, internal egg quality, and eggshell quality parameters. The coefficients of variation of each parameter were classified as low, intermediate, high, and very high according to the ratio between the median and the pseudo-sigma. It was concluded that the parameters used in experiments with commercial layers have a specific classification of coefficients of variation, and that this must be considered to evaluate experimental accuracy.
Abstract in English:Consumer demands for healthy foods have stimulated the research on the use of natural products in animal nutrition. Annatto can be used a pigmentation source to improve yolk color of commercial eggs. This study aimed at evaluating the effects of the inclusion of ground annatto seeds on the performance and egg quality of layers fed sorghum-based diets. A total of 336 40-w-old hens were distributed according to randomized blocks into seven treatments with six replicates of eight birds each. The following treatments were applied: T1- egg production feed based on corn and soybean meal; T2- egg production feed based on sorghum and soybean meal; T3, T4, T5, T6, and T7- egg production feed based on sorghum supplemented with 0.5, 1.0, 1.5, 2.0, and 2.5% ground annatto seeds, respectively. As to performance parameters, only egg production was influenced, with hens fed the corn-based diet producing more eggs than those fed the sorghum-based diet with inclusion of 1.5 and 2.5% de annatto. The only egg quality parameter affected by treatments was the color of yolk, which pigmentation increased with increasing levels of ground annatto seeds. It is concluded that ground annatto seeds can be supplemented in sorghum-based production feeds for layers, and that the inclusion level of 0.89% is sufficient to promote the same yolk pigmentation as that obtained with corn-based diets.
Abstract in English:Layer mortality due to heat stress is an important economic loss for the producer. The aim of this study was to determine the mortality pattern of layers reared in the region of Bastos, SP, Brazil, according to external environment and bird age. Data mining technique were used based on monthly mortality records of hens in production, 135 poultry houses, from January 2004 to August 2008. The external environment was characterized according maximum and minimum temperatures, obtained monthly at the meteorological station CATI in the city of Tupã, SP, Brazil. Mortality was classified as normal (£ 1.2%) or high (> 1.2%), considering the mortality limits mentioned in literature. Data mining technique produced a decision tree with nine levels and 23 leaves, with 62.6% of overall accuracy. The hit rate for the High class was 64.1% and 59.9% for Normal class. The decision tree allowed finding a pattern in the mortality data, generating a model for estimating mortality based on the thermal environment and bird age.
Abstract in English:This study aimed at determining the minimum time required for the penetration of Salmonella Heidelberg inside the eggs after contact with contaminated material. Recently-collected brown and white eggs from laying hens between 45-50 weeks of age, reared in a commercial poultry house, were artificially contaminated by contact with wood shavings moistened with liquid inoculum of Salmonella Heidelberg in stationary-growth phase (10³-10(4) CFU g-1). According to type (white or brown), eggs were distributed into three different groups, with four replicates each: negative control group (no artificial contamination), positive control group (analyzed externally immediately after contamination and internally after the maximum storage period of the test group) and test group. Eggs were stored at controlled environmental temperature varying from 25ºC to 30ºC. In the test group, eggs contents (yolk and albumen) were pooled and analyzed after 1:00, 1:30, 2:00, 2:30, 3:00, 3:30, and 4:00 hours after contamination for the presence of Salmonella Heidelberg in 25g of this pool. The experimental unit consisted of five eggs in each test. The analysis protocol included pre-enrichment, selective enrichment, plating on selective agar, and biochemical and serological tests. The results obtained were submitted to logistic regression, which indicated that the presence of Salmonella Heidelberg was verified after 2:16 h and 2:44 h of contact with white and brown eggs, respectively.
Abstract in English:Climate may affect broiler production, especially where there are heat waves, which may cause high mortality rates due to the heat stress. Heat wave prediction and characterization may allow early mitigation actions to be taken. Data Mining is one of the tools used for such a characterization, particularly when a large number of variables is involved. The objective of this study was to classify heat waves that promote broiler chicken mortality in poultry houses equipped with minimal environmental control. A single day of heat, a heat-shock day, is capable of producing high broiler mortality. In poultry houses equipped with fans and evaporative cooling, the characterization of heat waves affecting broiler mortality between 29 days of age and market age presented 89.34% Model Accuracy and 0.73 Class Precision for high mortality. There was no influence on high mortality (HM) of birds between 29 and 31 days of age. Maximum temperature humidity index (THI) above 30.6 ºC was the main characteristic of days when there was a heat wave, causing high mortality in broilers older than 31 days. The high mortality of broilers between 31 and 40 days of age occurred when maximum THI was above 30.6 ºC and maximum temperature of the day was above 34.4 ºC. There were two main causes of high mortality of broilers older than 40 days: 1) maximum THI above 30.6 ºC and minimum THI equal or lower than 15.5 ºC; 2) maximum THI above 30.6 ºC, minimum THI lower than 15.5 ºC, and the time of maximum temperature later than 15:00h. The heat wave influence on broiler mortality lasted an average of 2.7 days.