Abstract in English:Vertical integration in poultry industry strongly emphasizes the importance of cost control at all levels. In the usual broiler production operations, the costs involved with the production of the hatching egg or the day old chick are negligible if seen in the perspective of the cost per kg of live bird. From a research point of view, anyway, the greatest attention is usually given to the performance of broiler breeders, and most of the research in the field is focused on the improvement of their relative performance, mainly in terms of saleable chicks produced per hen, while less attention has been given to the quality of the chick and to the improvement of its growth performances, even if these last parameters have an effective impact on the overall economics of the poultry growing business. Most of the data available is quite dated, as can be seen from some recent reviews, and in general little attention is given to the impact of parental nutrition on the subsequent broiler performance. It is in fact more usual to find data about dam nutrition influence on egg fertility and hatchability than on subsequent progeny performance. The objectives of this review were to assess, on the basis of published reports, the effects of selected nutrients and anti-nutrients normally prevailing in commercial broiler breeder feeds - vitamins, micro-minerals, mycotoxins, - trying to pinpoint which could be the positive and the negative effects of both on the subsequent broiler performance, with a particular attention to the impact on immune function and carcass yield.
Abstract in English:This study aimed at evaluating the alternative method of zinc oxide and fasting to induce molt in Japanese quails. A total number of 190 48-week-old quails was used. They were at end of laying cycle, and presented low egg production. Quails molted by zinc oxide (Z) were fed a diet containing 25,000 ppm of zinc oxide, and received water ad libitum. Quails treated by fasting (F) received no feed and a day of water restriction. The treatment period was determined by the experimental level of body weight loss (BWL). Birds were submitted to different levels of BWL in order to analyze reproductive system regression (ovary + oviduct), and livability. The following groups were established according to their BWL: Control (untreated quails); F25 (25% BWL by F); F35 (35% BWL by F); Z25 (25% BWL by Z), and Z35 (35% BWL by Z). Z25, Z35, and F35 presented no significant differences in reproductive system weights after molting; however, their weights were lower than F. Z, Z, and F presented the following livability: 97.5, 72.5, and 90%. Japanese quails treated by the alternative method of zinc oxide, presenting body weight loss of 25%, showed low mortality rate, and adequate regression of the reproductive organs.
Abstract in English:The effects of vitamin E supplementation (300 mg/kg diet) in the diet of broiler chickens for different periods during rearing on the performance and qualitative traits of breast and leg muscles were evaluated. Seven hundred and twenty day-old chicks were distributed into six treatments: basal diet (25 mg vitamin E/kg diet), and diet supplemented with vitamin E from 1 to 15, 1 to 30, 1 to 45, 14 to 45 and 30 to 45 days of age. Vitamin E content, lipid percentage, TBARS (0 and 3 days of storage), color (*L, *a, *b), and pH were evaluated. There were no differences (p>0.05) among treatments in performance, carcass yield, and cut yields. Qualitative parameters (pH and color) presented no differences, although vitamin E positively affected TBARS values at 3 days of storage, mainly in leg muscles. Vitamin E levels in both muscles were higher in the birds supplemented throughout the experiment.
Abstract in English:The objective of this experiment was to evaluate the effect of a probiotic (Bacillus subtilis, strain DSM 17299) in broiler diets on feed intake, weight gain, and feed conversion ratio. The experiment included 1,200 male Ross broilers from 1 to 42 days of age. Birds were randomly allocated to 4 treatments, with 10 replicates of 30 birds. The following treatments were applied: T1 - Negative Control (basal diet, with no added growth promoter; T2 - Negative Control + Bacillus subtilis (8 x 10(5) CFUs/g feed); T3 - Negative Control + Bacillus subtilis (3 x 10(5) CFUs/ g de feed) and T4 - Positive Control (avilamycin + anticoccidial from 1 to 35 days of age). At 21, 35, and 42 days of age, there was an increase of antibiotic-free diet intake as compared to the diets with growth promoters (p<0.05), but there was no difference, however, as compared to the diets with probiotic as a growth promoter (p>0.05). The use of growth promoter did not improve weight gain at the studied ages. There was a marked improvement in the feed conversion ratio of broilers fed the diet with antibiotics and of broilers fed the diet with added B. subtilis. It is concluded that the Bacillus subtilis probiotic can be used as a growth promoter in broiler diets.
Abstract in English:This study aimed at verifying the possibility of replacing calcitic limestone by marine calcium in the diet of layers. A total number of 321 Hi-sex hens, with 40 weeks of age at the beginning of the experiment, was used. A completely randomized experimental design was applied, with 5 treatments (0, 15, 30, 45, and 60 % of calcitic limestone replacement by marine calcium source) and eight replicates of eight birds each. Treatments significantly affected specific gravity (p<0.05), with the inclusion of 60% marine calcium (T5) presenting the worst result as compared to T1, which included only calcitic limestone as calcium source. It was concluded that marine calcium can replace up to 45% of calcitic limestone with no effects on performance or egg quality.
Abstract in English:Six hundred and forty one-day-old Cobb male broilers were used to evaluate ornithine decarboxylase (ODC) expression in the mucosa of the small intestine. Birds were submitted to early feed restriction from 7 to 14 days of age. The provided feed was supplemented with glutamine. A completely randomized design with a 2 x 2 factorial arrangement was used (with or without glutamine, with or without feed restriction). Restricted-fed birds were fed at 30% the amount of the ad libitum fed group from 7 to 14 days of age. Glutamine was added at the level of 1% in the diet supplied from 1 to 28 days of age. Protein concentration in the small intestine mucosa was determined, and ODC expression at 7, 14, 21, and 28 days of age was evaluated by dot blotting. ODC was present in the mucosa of broilers, and the presence of glutamine in the diet increased ODC activation. Glutamine prevented mucosa atrophy by stimulating protein synthesis, and was effective against the effects of feed restriction. Dot blotting can be used to quantify ODC expression in the intestinal mucosa of broilers.
Abstract in English:In order to evaluate the effect of energy intake and broiler genotype on performance, carcass yield, and fat deposition, 600 one-day-old male chicks from two different genetic groups (AgRoss 308 - commercial line and PCLC - Embrapa non-improved line) were fed diets with different metabolizable energy level (2950, 3200 and 3450 kcal/kg). A completely randomized experimental design in a 2X3 factorial arrangement with four replications of 25 birds per treatment was applied. In order to ensure different energy intake among treatments within each strain, feed intake was daily adjusted by pair-feeding schemes. AgRoss 308 broilers had better performance and carcass yield, and presented lower abdominal fat deposition rate. In both genetic groups, the highest dietary energy level increased weight gain, heart relative weight, and fat deposition. However, it reduced the difference between AgRoss 308 and PCLC for feed conversion ratio and carcass protein deposition. These findings allow concluding that genetic improvement had a significant effect on broiler energy metabolism, and that the highest performance differences between genetic groups are found when low-energy intake is imposed.
Abstract in English:A total of 120 Pekin ducks were distributed at random into four experimental groups, vaccinated or not against Newcastle disease (ND): G1 (Ulster 2C strain), G2 (B1 strain), G3 (LaSota strain), and G4 (nonvaccinated group). At 60 days of age, all groups were challenged with a pathogenic ND virus (NDV) suspension, and a group of specific pathogen free (SPF) chicks (G5) was also inoculated. Cloacal and tracheal swabs from all birds were collected after six, 14, 20, and 30 days post-challenge for virus isolation. NDV was isolated in 100% of SPF chicks. Pekin ducks from all groups, vaccinated or not, did not show any ND clinical signs, demonstrating that these birds are not susceptible to ND clinical disease. In the control group (G4), the virus was isolated 20 to 30 days after challenge, suggesting their possible NDV carrier state. In the vaccinated groups, no virus was isolated. This demonstrates that vaccination of white Pekin ducks against NDV is important to reduce NDV shedding in the field.
Abstract in English:Dirt floors are used on most Brazilian poultry farms since the construction of concrete floors is very expensive. In vitro tests carried out to verify the effectiveness of disinfectants do not consider the adverse conditions found in poultry farms. Therefore, the present study aimed at evaluating the effect of six commercial disinfectants on the reduction of total and fecal coliforms on the dirt floor of breeder houses. The amount of disinfectant solution to be used per square meter was defined by counting total and fecal coliforms at different soil depths and by analyzing soil physical properties. Coliforms were detected at 0.5 cm, and one liter of disinfectant solution was sufficient for soil saturation at this depth. After that, the efficacy of six commercial products (caustic soda, hydrated lime, phenols 1 and 2, iodine, glutaraldehyde, and quaternary ammonium) in reducing the number of coliforms, after six hours of contact with the dirt floor, was assessed using the most probable number (MPN) method. Escherichia coli specimens isolated from the dirt floor were used to evaluate in vitro effectiveness of disinfectants. Products that yielded the best results in the MPN method were also effective in the in vitro tests. Among the tested disinfectants, hydrated lime was the most efficient, reducing the initial contamination by 2.9 log after six hours of contact with the dirt floor.
Abstract in English:This study aimed at evaluating the susceptibility of commercial laying hens to Salmonella Gallinarum (SG). Two experiments were carried using a mutant strain of Salmonella Gallinarum resistant to nalidix acid (SGNALr). In the first trial, the resistance of birds was evaluated based on clinical signs, faecal shedding, and mortality. It was carried out with six lines of commercial layers being three light white layers, considered to be resistant to SG (W1, W2, W3), and three semi-heavy brown varieties (B1, B2, B3), considered susceptible to SG. Each group contained 15 one-day-old birds. Hens were inoculated in the crop at 5 days of age with 0.2 mL of SGNALr neat culture. In addition, to each brown variety, a new group of 15 birds was challenged with 0.2mL of the same SGNALr culture diluted at 10-3. At the end of the first experiment, the surviving birds were sacrificed, and microbiological culture of liver and spleen was performed. In the second experiment, white and brown birds were inoculated with neat culture at five days of age. Samples were collected for evaluation of blood parameters and histopathology assessment at 1, 3, 5, 7, 9, 12, and 14 days post-infection. The results of the first experiment showed higher resistance of white birds (p<0.05), although there was no uniformity in the responses against fowl typhoid among the birds within these groups. In the second experiment, there were differences between white and brown birds both in blood parameters and in organ lesion intensity.