-An experiment employing three hundred and twenty 81-week-old Lohmann LSL commercial-breed hens was conducted to compare alternative induced-molting methods with the conventional method (fasting). Induced molting lasted 28 days at most, production and quality being monitored for four periods of 28 days thereafter. A completely randomized experimental design with five treatments, eight replicates of eight birds each per plot was adopted. The following experimental treatments were applied until a loss of 26% of body weight was reached: T1 -fasting, T2 -wheat bran ad libitum, T3 -rice bran ad libitum, T4 -cracked rice ad libitum, T5 -ground alfalfa ad libitum. Birds were then fed production diet ad libitum, except for those on treatment T1 (fasting) which received 30, 60 and 100 g/bird/day and then feed ad libitum. During induced molting the birds were exposed to a natural photoperiod and at day 28 that period was increased by 30 minutes/week until reaching 16 hours of light/day. The characteristics evaluated during induced molting were: feed intake, body weight changes and laying percentage. In the post-molt period, performance (feed intake, laying percentage, egg weight, egg mass, feed conversion ratio per dozen and per egg mass and percentage of broken eggs) and egg quality (specific gravity, eggshell breaking strength, percentages of eggshell, yolk, and albumen, eggshell thickness, yolk color and Haugh unit) were evaluated. Every 28 days one egg was collected from each repetition for three consecutive days for quality assessment. The use of rice bran and wheat bran is viable as molting inducers since the birds given those treatments display performance and egg quality similar to those fasted during the induced molting and also because these ingredients promote easier handling, eliminates the need for grinding and feed-mixing equipment and, being less aggressive, provide greater bird welfare.
The experiment was carried out in the experimental poultry house of the Research and Development Unit of Brotas of Agência Paulista de Tecnologia dos Agronegócios do Centro-Oeste, SP, Brazil. The objective of the study was to evaluate the performance of Japanese quails submitted to forced molting aiming at optimizing the use of the same quail flock by promoting a second laying cycle. A total number of 400 67-day-old Japanese quails in lay, previously submitted to 14 days of forced molting, was distributed in a completely randomized experimental design into five treatments (T1= not submitted to forced molting, T2= 03 days of fasting + fed ad libitum, T3= 01 days of fasting + 13 days of feed restriction, T4= 02 days of fasting + 12 days of feed restriction, and T5= 03 days of fasting + 11 days of feed restriction. Feeds were contained equal nutrient levels, and were formulated according to NRC (1994) recommendations. There were significant differences among the studied treatments. Although the treatment of 3 days of fasting followed by ad libitum feeding resulted in lower egg weight, it promoted better lay percentage, egg mass, and feed conversion ratios (FCR/dz and FCR/kg). On the other hand, 3 days of fasting followed by restricted feeding resulted in higher feed intake and worse feed conversion ratios (FCR/dz and FCR/kg). When birds were not submitted to forced molting, they presented lower lay percentage and egg mass
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.
This study was performed to evaluate the effects of the association of different digestible arginine and phytogenic additive dietary levels on performance and health status of brown-egg layers. In this study, a total of 504 33-week-old Hisex Brown layers were distributed into a completely randomized experimental design to a 4 × 3 factorial arrangement (dietary digestible arginine levels: 880, 968, 1056, or 1144 mg/kg of feed × phytogenic additive levels: 0, 100, and 200 mg/kg of feed) with six replicate cages of seven birds per cage. The phytogenic additive was composed of extracts of Baccharis dracunculifolia (40%), Astragalus membranaceus lipopolysaccharides (20%), cinnamon, and grape seed (20%). Feed intake was reduced when diets containing 1056 mg of arginine were supplemented with 100 or 200 mg phytogenic additive per kg. Feed conversion ratio was improved when diets were supplemented with 100 mg of phytogenic additive or with 1056 mg of arginine per kg of feed. Egg mass was increased when diets were supplemented with 1056 mg arginine per kg of feed. Arginine supplementation quadratically increased albumen percentage and reduced yolk percentage. Higher arginine and phytogenic additive levels reduced heterophyl:lymphocyte ratio and blood uric acid, total cholesterol, very-low density lipoprotein, and triglyceride levels. Dietary supplementation of 100 mg of phytogenic additive associated with high arginine levels increased nitric oxide production by peritoneal macrophages and 1056 mg of arginine increased antibodies titers against Newcastle disease virus. Blood and intestinal malonaldehyde levels were reduced when 200 mg of the phytogenic additive was added. Dietary supplementation of 968 mg of arginine or 100 mg of a phytogenic additive (40% Baccharis dracunculifolia, 20% Astragalus membranaceus, 20% cinnamon, and 20% grape seed extracts) per kilogram of diet improves the feed conversion ratio and associated inclusion of 1144 mg of arginine and 100 mg of phytogenic additive per kilogram of diet improves immune responses and health status of brown-egg layers.
The objective of this study was to evaluate the effects on gamma radiation levels on the physical and microbiological characteristics of chicken breast meat. A completely randomized experimental design in a 4x2x3 factorial arrangement was adopted. Treatments consisted of four radiation concentrations (0, 2, 4, or 8kGy), two package sealing methods (with or without vacuum), and three storage times (01, 07, or 14 days), with ten replicates each, totaling 240 chicken breast fillets. Packaging and radiation had no influence (p>0.05) on chicken breast meat pH, water retention capacity, or presence of Salmonella spp. Breast fillets not submitted to radiation and vacuum packed presented higher water retention capacity (p<0.05) than those radiated at 4kGy and vacuum packed. Drip loss in fillets radiated at 8kGy and not vacuum packed was higher (p<0.05) than in non-radiated and non-vacuum packed fillets; however, both were not different from the other treatments. Coliform presence increased with storage time in non-radiated samples; however, when these were vacuum-packed, their development was slower. The results of the present experiment suggest that the use of a low radiation dose (2kGy), combined with vacuum packing, may minimize the harmful effects of storage on chicken breast fillets.
Abstract:We investigated the effects of a combination of protease, xylanase, and phytase in maize-or sorghum-based diets for broilers. Two experiments were conducted with male chicks randomly distributed in a 3 × 2 factorial arrangement with three replacement levels of maize with sorghum (0%, 50%, and 100%) with or without enzymes. In the first trial, 1152 chicks were allotted to 36 floor pens to determine performance, relative organ weight, and litter moisture. A second trial was performed with 150 and 120 chicks allotted in 30 cages with five and four broilers per cage to determine nutrient and energy utilization from 11 to 21 d and from 25 to 35 d, respectively. Enzyme supplementation improved body-weight gain and feed conversion ratio. Total maize replacement with sorghum compromised body-weight gain from 1 to 14 d and from 1 to 35 d. Nitrogen retention was reduced by partial and total maize replacement with sorghum at starter phase and by total replacement at grower phase. Enzyme supplementation improved nitrogen retention at starter phase and apparent metabolizable energy at starter and grower phases. Therefore, partial maize replacement with sorghum is viable and on top application of an enzyme blend containing protease, xylanase, and phytase improves performance and nutrient retention of broilers.Key words: maize, sorghum, exogenous enzymes, nutrient retention, broiler chicken.Résumé : Nous avons examiné les effets d'une combinaison de protéases, xylanases et phytases dans les diètes à base de maïs ou de sorgho chez les poulets à griller. Deux expériences ont été effectuées chez des poussins mâles distribués de façon aléatoire dans un design factoriel 3 × 2 avec trois niveaux de remplacement du maïs par le sorgho (0 %, 50 % et 100 %) avec ou sans enzymes. Dans la première étude, 1152 poussins ont été alloués à 36 enclos au sol pour déterminer la performance, le poids relatif des organes et l'humidité contenue dans la litière. La deuxième étude a été effectuée avec 150 et 120 poussins attribués à 30 cages avec cinq et quatre poulets par cage pour déterminer l'utilisation des éléments nutritifs et de l'énergie des jours 11 à 21 et des jours 25 à 35, respectivement. Les suppléments d'enzymes ont amélioré le gain de poids ainsi que l'indice de consommation. Le remplacement total du maïs par le sorgho a compris le gain de poids des jours 1 à 14 et des jours 1 à 35. La rétention d'azote a été réduit par le remplacement partiel ou total du maïs par le sorgho dans la phase initiale ainsi que par le remplacement total dans la phase de croissance. Les suppléments d'enzymes ont amélioré la rétention d'azote dans la phase initiale et l'énergie métabolisable apparente corrigé pendant les phases initiales et de croissance. Donc, le remplacement partiel du maïs par le sorgho est une solution viable et l'application d'un mélange d'enzymes contenant des protéases, xylanases et phytases améliore la performance et la rétention des éléments nutritifs chez les poulets à griller. [Traduit par la Rédaction]
Among the different feed additives studied in poultry production, clinoptilolite, an aluminosilicate capable of adsorbing harmful substances and of improving live performance and egg and meat quality, was evaluated. The objective of the present study was to evaluate the influence of dietary clinoptilolite and calcium levels on the performance and egg quality of layers. In total, 576 layers were distributed according to a completely randomized experimental design in a 3 x 4 factorial arrangement (three calcium levels-2.5, 3.1, or 3.7% and four clinoptilolite levels-0.0, 0.15, 0.25, or 0.50%), with 12 treatments of six replicates of eight birds each. The experiment included four 28-d cycles. The experimental diets were based on corn and soybean meal. Results were submitted to analysis of variance and means were compared by the test of Tukey at 5% significance level using SISVAR statistical package. There was a significant interaction between the evaluated factors for egg production and feed conversion ratio per dozen eggs and egg mass. The lowest calcium level resulted in worse performance and eggshell quality. Clinoptilolite levels affected albumen and yolk content. It was concluded that up to 0.50% inclusion of clinoptilolite in layer diets does not benefit layer performance or eggshell quality. Although the inclusion of only 2.5% calcium in layer diets is not recommended, it is possible to add 3.1% because it promoted similar results as the recommended level of 3.7%.
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