Different phytase levels and energy densities in broiler diets on performance, nutrient digestibility, and bone integrity from 28 to 35 days of age / Diferentes níveis de fitase e de densidades energéticas em dietas de frangos de corte sobre desempenho, digestibilidade de nutrientes e integridade óssea de 28 a 35 dias de idade

The study was carried out with the objective of evaluating the effects of using phytase levels at different energy densities in the diet of broilers, from 28 to 35 days of age. The experimental diets contained increasing levels of apparent metabolizable energy corrected for nitrogen balance and different levels of phytase. Growth performance variables, nutrient digestibility, as well as variables related to bone integrity were examined. Diets containing 500 FTU/kg in combination with 3150kcal.kg-1 of AMEn resulted in better growth performance. Supplementation with 500 and 1000 FTU/kg in the diets provide better coefficients of apparent and ileal digestibility of calcium and phosphorus, but negatively influence the deposition of calcium, phosphorus, dry matter, and ash in the tibia, in addition to adversely affecting the breakage and area of these bones in broilers. Bone length and the levels of magnesium and zinc present in the tibias were not influenced by the energy and phytase levels of the diets. There is no interaction between the different energetic densities and the phytase doses in the variables analyzed in the studied period. Increasing the energy density of diets resulted in improved apparent and ileal digestibility for most nutrients.

O estudo foi realizado com o objetivo de avaliar os efeitos da utilização de níveis de fitase em diferentes densidades energéticas na dieta de frangos de corte, no período de 28 a 35 dias de idade. As dietas experimentais contiveram níveis crescentes de energia metabolizável aparente corrigida para balanço de nitrogênio e diferentes níveis de fitase. Foram avaliadas variáveis de desempenho zootécnico, digestibilidade de nutrientes e variáveis relacionadas à integridade óssea. Dietas contendo 500 FTU/kg de fitase em combinação com 3150kcal.kg-1 de EMAn resultam em melhor desempenho zootécnico. A suplementação com 500 e 1000 FTU/kg nas dietas propicia melhores coeficientes de digestibilidade aparente e ileal do cálcio e do fósforo, mas influencia negativamente na deposição de cálcio, fósforo, matéria seca e cinzas das tíbias, além de afetar adversamente a quebra e a área desses ossos em frangos de corte. O comprimento do osso e os níveis de magnésio e zinco presentes nas tíbias não são influenciados pelos níveis energéticos e de fitase das dietas. Não há interação entre as diferentes densidades energéticas e as doses de fitase nas variáveis analisadas no período estudado. O aumento da densidade energética das dietas resulta em melhora na digestibilidade aparente e ileal para a maioria dos nutrientes.

Stabilization of Rice Bran in Broiler Feed with Natural and Synthetic Antioxidants and Heat Treatment

The objective of this study was to evaluate different strategies for the oxidative stabilization of rice bran (RB) in the diet of broiler chickens using natural antioxidant additives, synthetic antioxidant additives and heat treatment on performance, breast meat quality and liver fat content and the nutrient digestibility coefficients. Furthermore, the study aimed to evaluate the effects of heat treatment and antioxidants, antioxidant additive treatments, without antioxidants, natural, and synthetic, and to three heat treatments, without heat, dry-heat and moist-heat, after the rice bran was stored for 90 days and then incorporated into the experimental diets. 1080 broilers were arranged in a 3 x 3-factorial randomized design with 10 replicates per treatments. The wet heat treatment of the meal resulted in a higher daily feed intake and body weight at 28 days and better feed conversion than did the meal without heat treatment. No significant interactions were observed between the tested factors on the apparent digestibility of dry matter and ether extract as well as the values of apparent metabolizable energy and apparent metabolizable energy corrected for nitrogen. However, there was significant interaction between the tested factors on the nitrogen retention coefficient; the natural antioxidant and dry heat-treated meal combination presented a lower crude protein digestibility coefficient than those without heat treatment. In conclusion, thermal treatment of this bran proved to be more effective as demonstrated by the performance responses of the birds. Broiler chickens reared up to 28 days of age consuming diets containing 6.5% RB stabilized by heat treatment showed better performance, and the use of antioxidants was not necessary.(AU)

Stabilization of Rice Bran in Broiler Feed with Natural and Synthetic Antioxidants and Heat Treatment

The objective of this study was to evaluate different strategies for the oxidative stabilization of rice bran (RB) in the diet of broiler chickens using natural antioxidant additives, synthetic antioxidant additives and heat treatment on performance, breast meat quality and liver fat content and the nutrient digestibility coefficients. Furthermore, the study aimed to evaluate the effects of heat treatment and antioxidants, antioxidant additive treatments, without antioxidants, natural, and synthetic, and to three heat treatments, without heat, dry-heat and moist-heat, after the rice bran was stored for 90 days and then incorporated into the experimental diets. 1080 broilers were arranged in a 3 x 3-factorial randomized design with 10 replicates per treatments. The wet heat treatment of the meal resulted in a higher daily feed intake and body weight at 28 days and better feed conversion than did the meal without heat treatment. No significant interactions were observed between the tested factors on the apparent digestibility of dry matter and ether extract as well as the values of apparent metabolizable energy and apparent metabolizable energy corrected for nitrogen. However, there was significant interaction between the tested factors on the nitrogen retention coefficient; the natural antioxidant and dry heat-treated meal combination presented a lower crude protein digestibility coefficient than those without heat treatment. In conclusion, thermal treatment of this bran proved to be more effective as demonstrated by the performance responses of the birds. Broiler chickens reared up to 28 days of age consuming diets containing 6.5% RB stabilized by heat treatment showed better performance, and the use of antioxidants was not necessary.

Coccidiosis and performance in broilers with anticoccidial medicated feed starting at different ages

The effects of age, litter reutilization, and anticoccidial programs were studied in broilers. The oocyst counts increased with litter reutilization up to third use, and T1 (no anticoccidial drug over the entire 42-day-period) and T4 (anticoccidial medication starting from the first day) showed the highest counts. The scores for Eimeria acervulina increased up to third use of litter and declined by the fourth use. The scores for E. maxima increased from first to second litter use, and from this to third and fourth use. The scores for E. tenella increased from first and second litter use to third litter use, and declined on fourth use. With high coccidial contamination, as in third use litter, the anticoccidial medication starting from the 1st, 7th (T3) and 14th (T2) day of age presented similar results of lesion scores and average weight gain. When coccidial contamination was low or moderate, as in first, second and fourth use litter, the anticoccidial medication starting at 14 days of age tended to result in a better broiler performance. These data suggest that, with low coccidial challenge, as in broilers raised in first use litter and in farms with single bird age, the delayed anticoccidial medication may provide advantages over the full medication starting from the first day of age.

Estudou-se o efeito da idade das aves, da reutilização da cama vegetal e de programas anticoccidianos na coccidiose e desempenho de frangos. Utilizaram-se quatro lotes de 24 pintos cada (um dia de idade) submetidos a quatro tratamentos (T): T1 - aves não tratadas com anticoccidiano, T2 - aves medicadas com anticoccidiano a partir do 14º dia de vida, T3 - aves medicadas com anticoccidiano a partir do sétimo dia de vida, T4 - aves medicadas com anticoccidiano a partir do primeiro dia de vida. As contagens de oocistos aumentaram com a reutilização da cama, no terceiro lote. T1 (sem anticoccidiano) e T4 (anticoccidiano desde o primeiro dia) apresentaram as maiores contagens. Os escores por Eimeria acervulina aumentaram no terceiro lote e baixaram no quarto lote. Os escores por E. maxima aumentaram no segundo lote, e deste para o terceiro e quarto lotes. Os escores por E. tenella aumentaram no terceiro e quarto lotes. Com desafio alto, como ocorrido no terceiro lote, as medicações anticoccidianas a partir do primeiro, sétimo e 14º dias resultaram em desempenhos semelhantes. Com desafios baixos ou moderados, como ocorridos nos lotes 1, 2 e 4, a medicação a partir do 14º dia resultou em melhores desempenhos. Isso sugere que, em condições de baixo desafio, como em frangos criados em cama de primeiro uso e em granjas com aves de uma única idade, a medicação anticoccidiana a partir de 14 dias pode ser vantajosa em relação aos programas de medicação a partir do primeiro dia.