Abstract in English:Nutrition for broilers under high temperatures is extremely important for brazilian broiler chicken industry because the amounts of consumed nutrients and environmental temperature have great effects on bird performance and carcass quality. Among diet nutrients, protein has the highest heat increment; thus, during many years, diets with low protein level were recommended in order to reduce heat production in broiler chickens under heat stress. However, reports have shown that low-protein diets have negative effects on broiler performance when environmental temperature is high, because during heat stress, low food intake associated to a low diet protein induce amino acid deficiencies. Other studies have shown that broilers fed low-protein diets increase their energy requirement for maintenance with higher heat production. Thus, with the growth of broiler industry in tropical areas more challenges need to be faced by the farmers. So, both the ambient and nutritional conditions ought to be well managed to avoid negative effects on poultry production once they can affect the metabolism (body heat production under low temperature and body heat dissipation under high temperature) with consequence on poultry performance (meat and eggs).
Abstract in English:This experiment was carried out to evaluate the effects of replacing corn by high tannin sorghum in diets of japanese quails (Coturnix coturnix japonica) on performance and egg quality. Two hundred and fifty-two quails with 50 weeks of age were evaluated during four periods of 21 days. The treatments consisted of diets containing 20, 40, 60, 80 and 100% of sorghum, and a control treatment (100% of corn). Diets were formulated so that the levels of energy, protein, amino acids (methionine+cystine and lysine), calcium and phosphorus were similar A completely randomized experimental design was used, with six treatments, six replicates and seven quails for experimental unit. Evaluated parameters were egg production (%), feed intake, feed: gain ratio (kg/kg and kg/dozen), egg mass (g), egg weight and egg quality (Haugh unit, eggshell percentage, shell thickness and yolk color). The increasing sorghum levels had a negative linear effect (p<0.05) on egg production (Y=82.9138 - 0.0966553X; R²=0.87), egg mass (Y= 8.0840626 - 0.009336932X; R²=0.80) and yolk color (Y=7.14340-0.0546875X; R²=0.98). On the other hand, the replacement had a positive linear effect on feed:gain ratio expressed as kg/kg (Y=0.372174 + 0.000536191X; R²=0.92) and as kg/dozen (Y=2.71516 + 0.00423485X; R²=0.94). Control treatment means were different by Dunnett's test (p<0.05) for egg mass (g) when compared to the treatment with 100% of replacement and for yolk color when compared to treatments containing 20, 40, 60, 80 and 100% of sorghum. There were no differences (p>0.05) in feed intake, egg weight, Haugh unit, eggshell percentage and shell thickness. In conclusion, up to 80% of high tannin sorghum may be used on diets if xanthophyll pigments are added in order to maintain the commercial quality of final products.
Abstract in English:This study was conducted to evaluate the performance and carcass and breast yields of broilers fed two different energy levels (3,200 or 2,900 kcal ME/kg) and two ways of expressing amino acid requirements (total - TAA or digestible - DAA) between 21 and 42 days of age. The results showed that broilers fed the diet containing 3,200 kcal ME/kg had higher weight gain (P=0.015), better feed conversion (P=0.001), and higher abdominal fat deposition (P=0.001) as compared to those fed the diet containing 2,900 kcal ME/kg. Diets formulated on DAA basis promoted higher weight gain (P=0.043), better feed conversion (P=0.010) and better conversion of ME intake into weight gain (P=0.007) as compared to those formulated on TAA basis. The results of this study suggest that formulation based on DAA is necessary if the diets contain protein sources that are not reliable in terms of amino acid digestibility. The response to formulation based on DAA was minimized when birds received the low energy level diet (2,900 kcal ME/kg).
Abstract in English:Dietary lysine has been shown to impact the performance of broilers, particularly with aspect of breast meat accretion and yield. There have been studies that suggest that early dietary lysine has an effect on breast meat yield in male broilers. A study was designed to evaluate starter dietary lysine (1.20 vs 1.35% of diet as achieved by the addition of L-lysine at the expense of a filler) effect on performance of female broilers from three different genetic strain crosses, and monitor subsequent effects at 41 and 56 d of age. Body weight and feed consumption were higher for birds consuming the high lysine starter diet, but feed conversions were similar when compared to the low lysine diet. Body weight and feed conversion were similar among strains. Mortality was unaffected by lysine level and strain cross. Carcass and breast meat weight, but not yields, were higher in birds fed the high lysine diet. At 56 d differences in carcass yield, abdominal fat, and breast meat yield were seen among strains, such that the strain with highest yield had the least amount of abdominal fat in terms of absolute weight and percentage. No effect on processing yields by dietary lysine was observed at any time regardless of the growing characteristics of the broilers. However, for early slaughter ages, feeding high levels of dietary lysine during the starter phase could prove to be convenient when maximum live performance or breast meat absolute values are desiredin order to maintain the commercial quality of final products.
Abstract in English:This work aimed to evaluate the effects of probiotic associated to prebiotic on performance, carcass and cut yields, qualitative traits of meat, development and score of lesions due to coccidiosis in digestive tract of broiler chickens raised in a free-range system during 85 days. One thousand, six hundred and ninety-six day-old male broiler chicks from naked-neck ISA S757-N Label Rouge line were used in a randomized block design with factorial scheme of 4x2 and four repetitions. The effect of four additive (1 - biologic promoter + coccidiosis vaccine; 2 - biologic promoter + anti-coccidiosis; 3 - chemical promoter + coccidiosis vaccine; 4 - chemical promoter + anti-coccidiosis) and two breeding systems from 35th day of age (one with no-access to pasture or confined and the other with free-access to pasture or semi-confined) on performance parameters, carcass and cut yields, qualitative meat traits, coccidiosis development and lesions in digestive tract were evaluated. There was effect (p<0.05) of additives only on sensorial analysis (meat quality) and percentage of large intestine. Breeding systems affected (p<0.05) live weight (LW) and LW gains, being the better results observed in semi-confined birds.
Abstract in English:Food products such as breads, cakes, crackers, meringues, ice creams and several bakery items depend on air incorporation to maintain their texture and structure during or after processing. Proteins are utilized in the food industry since they improve texture attributes through their ability to encapsulate and retain air. The objectives of this work were to quantify s-ovalbumin contents in albumen and to determine alterations in egg white foam stability in fresh eggs, and in eggs coated and non-coated with a whey protein-based concentrate film (WPC), stored at 25°C for 28 days. The volume of drained liquid was higher in non-coated eggs than in coated eggs stored at 25°C at all storage periods. The difference on the third day of storage was in the order of 59% between coated and non-coated eggs, while on the twenty-eighth day it was 202%. During the storage period, an increase in pH and drainage volume was observed for non-coated eggs. After three days, the non-coated eggs showed a s-ovalbumin content 33% higher than coated eggs; this increase jumped to 205% at 28 days of storage. There was a positive correlation between s-ovalbumin content and the volume of drained liquid for coated and non-coated eggs; in other words, when the s-ovalbumin content increased, there was an increase in the volume of drained liquid and a decrease in foam stability. WPC coating maintain egg quality, since it is an effective barrier against the loss of CO2, avoiding changes in the pH of egg white.
Abstract in English:This study was done to assess an enzyme-linked immunosorbent assay (ELISA) to detect chicken serological response against Salmonella enterica serotypes Gallinarum and Pullorum. The assays have used soluble bacterial proteins of Salmonella Gallinarum strain 9 (AgSG) as detecting antigen and peroxidase and alkaline phosphatase conjugates. According to the results, the antigen, sera and conjugate concentrations were optimized. In addition, the assay using alkaline phosphatase and peroxidase conjugates was helpful to distinguish positive serological reaction to serotypes Gallinarum and Pullorum from Enteritidis.
Abstract in English:The present work was carried out to compare Infectious Bronchitis Virus (IBV) antibody titers in serum and egg yolk samples from laying hens. Sixty paired blood and egg samples were collected from laying hens of two farms. Serum samples were frozen, while egg yolk samples were diluted (1:500) before freezing. Serum and yolk samples were tested for the presence of IBV antibodies by indirect ELISA (commercial kit) and titers were compared by a correlation test (alpha=0.05). There was a high correlation (r=0.62) between the two kinds of samples, which means that titers of IBV antibodies in the egg yolk and in serum samples are quite the same. Considering that blood collection causes deep stress that leads to economic losses, and since eggs are collected daily on the farm, results reported here are of importance to poultry production.
Abstract in English:Occurrence of food poisoning related to Salmonella-contaminated eggs and chicken meat has been frequent in humans. Salmonella Enteritidis (SE) and Salmonella Typhimurium (ST) are included among the most important paratyphoid salmonellae associated with chicken meat and eggs. Elimination of Salmonella at the pre-harvest stage can play a significant role in preventing the introduction of this pathogen into the food chain and consequently in the reduction of food poisoning in humans. Bactericidal bacteriophages may provide a natural, nontoxic, feasible and non-expensive component of the multi-factorial approach for a pre-harvest control of Salmonella in poultry. Five bacteriophages lytic for SE PT4 and ST were obtained from 107 samples of feces of free-range layers in Brazil. All bacteriophages were characterized in vitro and in vivo, showing head and tail morphology and dsDNA as nucleic acids. Results of "in vivo" studies suggested that bacteriophages do not remain in Salmonella-free birds longer than one day, whereas they multiply in Salmonella-infected birds for longer periods. Besides, selection for phage-resistant SE PT4 did not seem to occur in the short term. Isolated bacteriophages will be investigated for their potential for pre-harvest biocontrol of SE PT4 in poultry.
Abstract in English:A study about coccidiosis in Japanese quails was carried out in order to identify species of the genus Eimeria and characterize a naturally occurring infection in a commercial rearing farm. For this purpose, fecal exams, oocyst counting and morphological study were performed, besides necropsy and histopathology to confirm diagnosis. Three species of the genus Eimeria were found and identified as E. tsunodai, E. uzura and E. bateri. The natural infection was characterized as subclinical because of the mild and nonspecific clinical signs. Nevertheless, coccidiosis was considered an important disease because endogenous stages of the parasites and a high number of oocysts in feces were associated with intestinal lesions. The results suggest that such infection might represent a limiting factor to this branch of the modern poultry industry.