Respostas fisiológicas e de desempenho de leitões suplementados com B-glucanos e desafiados imunologicamente / Phisiologial responses and growth performance of immune challenged piglets supplemented with B-glucans

O estudo buscou avaliar as respostas fisiológicas e de desempenho à adição de diferentes níveis de β-glucanos na dieta de leitões recém-desmamados. Foram utilizados 30 machos de linhagem comercial, com 34 dias de idade e peso de 10,9±0,63kg, alojados em gaiolas individuais, durante 14 dias. Os tratamentos variaram somente nos níveis de β-glucanos que foram de 35, 70, 140 e 280g/T. No final desse período, em metade dos animais foram injetados 2,7mg de lipopolissacarídeo (LPS) em 1mL de solução (PBS)/leitão, e nos demais 1mL/leitão de PBS. Foram avaliadas temperatura retal (TR), frequência respiratória (FR), perfil bioquímico sanguíneo e sinais clínicos aos 30, 90, 120 e 390 minutos seguintes à injeção. As respostas de desempenho não foram afetadas pelos níveis de β-glucanos. Foi observado o aumento de TR, tanto em função do LPS como em função da hora em que a temperatura foi medida. No entanto, os animais LPS-injetados, que receberam 280g/T de β-glucanos, tiveram a mesma TR daqueles LPS-não injetados. Os sinais clínicos foram compatíveis com um quadro de inflamação aguda e foram observados, nos animais LPS-injetados, vômito, prostração e diarreia, sendo que a inclusão de β-glucanos não conseguiu reverter esses sintomas. O uso de β-glucanos por 14 dias na dieta de leitões recém-desmamados mostrou um efeito anti-inflamatório em situação de desafio agudo. Para reverter o desafio imunológico utilizado, o nível de 280g/T de β-glucanos mostrou-se o mais recomendado.

This study was done to evaluate immunological responses and performance of weaning piglets receiving diets with different levels of β-glucans. Thirty males from a commercial line with 34 days of age and 10.9±0,6kg initial weight were housed in individual metabolic cages during 14 days. The treatments only differed in β-glucans levels: 35; 70; 140 and 280g/T. On the 14th day, half of the pigs were inoculated with 2.7mg LPS (lipopolysaccharide)/mL of solution (PBS)/pig and the other half received 1mL PBS/pig. Rectal temperature (RT), respiratory frequency (RF), biochemical profile and animal behavior (120 and 390 minutes after LPS inoculation) were evaluated. As the experiment was conducted, performance was not affected by β-glucans. An RT increase was observed due to LPS and time of temperature measurement. LPS-injected animals receiving 280g/T of β-glucans had the same RT as the LPS- non injected group. Clinical signs were near the expectation for acute inflammation. LPS-injected presented prostration, diarrhea and vomit and the β-glucans did not reverse this situation. The use of β-glucans in weaning pigs for fourteen days showed an anti-inflammatory action. To revert the immunologic challenge, the level of 280g/T of β-glucans was the most recommended.

Effect of vitamin E levels on the cell-mediated immunity of broilers vaccinated against coccidiosis

Studies on the relationships between animal nutrition and immunity have sought reliable methodologies to measure responses. Cell-mediated immune response is similarly studied in humans. The cutaneous basophil hypersensitivity test (CBH) is one of the methods to measure that response and consists in the infiltration of inflammatory cells, particularly of lymphocytes and basophils, as result of the application of substances capable of inducing cell proliferation in determined sites, such as wings, wattle, and interdigital space in birds. CBH is considered a simple and fast method and can be applied in birds of different ages. In immunocompetence studies with poultry, phytohemagglutinin-P (PHA-P) is a commonly used substance, despite the variability of the response related to the method of application (intradermal injection) and the antigens used. In the present experiment, PHA-P was used to observe the cell-mediated immune response of 216 chicks fed three dietary levels of vitamin E from 1 to 36 days of age. All birds were immunologically challenged by vaccination against coccidiosis at three days of age and against Newcastle Disease (NCD) at 14 and 30 days of age. At 36 days of age, birds were submitted to the CBH test according to the methodology of Corrier & DeLoach (1990). Birds fed 65mg/kg of vitamin E presented lasting cell reaction (p<0.08), which indicates that this vitamin E level improved cell immune response of birds due to its antioxidant and immunomodulating properties. The use of this vitamin E level can be considered by nutritionists under practical conditions, aiming to improve broiler immunity.

Effect of vitamin E levels on the cell-mediated immunity of broilers vaccinated against coccidiosis

Studies on the relationships between animal nutrition and immunity have sought reliable methodologies to measure responses. Cell-mediated immune response is similarly studied in humans. The cutaneous basophil hypersensitivity test (CBH) is one of the methods to measure that response and consists in the infiltration of inflammatory cells, particularly of lymphocytes and basophils, as result of the application of substances capable of inducing cell proliferation in determined sites, such as wings, wattle, and interdigital space in birds. CBH is considered a simple and fast method and can be applied in birds of different ages. In immunocompetence studies with poultry, phytohemagglutinin-P (PHA-P) is a commonly used substance, despite the variability of the response related to the method of application (intradermal injection) and the antigens used. In the present experiment, PHA-P was used to observe the cell-mediated immune response of 216 chicks fed three dietary levels of vitamin E from 1 to 36 days of age. All birds were immunologically challenged by vaccination against coccidiosis at three days of age and against Newcastle Disease (NCD) at 14 and 30 days of age. At 36 days of age, birds were submitted to the CBH test according to the methodology of Corrier & DeLoach (1990). Birds fed 65mg/kg of vitamin E presented lasting cell reaction (p 0.08), which indicates that this vitamin E level improved cell immune response of birds due to its antioxidant and immunomodulating properties. The use of this vitamin E level can be considered by nutritionists under practical conditions, aiming to improve broiler immunity.

Effect of vitamin E levels on the cell-mediated immunity of broilers vaccinated against coccidiosis

Studies on the relationships between animal nutrition and immunity have sought reliable methodologies to measure responses. Cell-mediated immune response is similarly studied in humans. The cutaneous basophil hypersensitivity test (CBH) is one of the methods to measure that response and consists in the infiltration of inflammatory cells, particularly of lymphocytes and basophils, as result of the application of substances capable of inducing cell proliferation in determined sites, such as wings, wattle, and interdigital space in birds. CBH is considered a simple and fast method and can be applied in birds of different ages. In immunocompetence studies with poultry, phytohemagglutinin-P (PHA-P) is a commonly used substance, despite the variability of the response related to the method of application (intradermal injection) and the antigens used. In the present experiment, PHA-P was used to observe the cell-mediated immune response of 216 chicks fed three dietary levels of vitamin E from 1 to 36 days of age. All birds were immunologically challenged by vaccination against coccidiosis at three days of age and against Newcastle Disease (NCD) at 14 and 30 days of age. At 36 days of age, birds were submitted to the CBH test according to the methodology of Corrier & DeLoach (1990). Birds fed 65mg/kg of vitamin E presented lasting cell reaction (p<0.08), which indicates that this vitamin E level improved cell immune response of birds due to its antioxidant and immunomodulating properties. The use of this vitamin E level can be considered by nutritionists under practical conditions, aiming to improve broiler immunity.(AU)

Comparison of the effects of semi-refined rice oil and soybean oil on meat oxidative stability, carcass yield, metabolism, and performance of broilers

Two experiments (EXP 1 and EXP 2) were conducted to compare soybean oil (SO) and semi-refined rice oil (RBO) added to broilers diets. In EXP 1, 400 male Ross x Ross 308 broilers were reared in battery cages, and their performance was evaluated. A metabolism assay was performed. In EXP 2, 1344 broilers from the same strain were reared in floor pens with rice husks litter. In addition to performance, carcass yield and meat oxidative stability were evaluated. In both EXP, birds were distributed in a 2x4 factorial arrangement, with two types of oils (SO or RBO) and four oil inclusion levels (1%, 2.5%, 4%, or 5.5%). Two periods were considered: starter (1 to 21 days of age) and grower (22 to 42 days). In both EXP, oil type had no influence on starter performance. Although treatments promoted similar in weight gain (WG) and feed intake (FI), grower birds fed RBO had better feed conversion (FCR) in EXP 2, but not in EXP1. In both trials, increasing dietary oil levels negatively influenced FI and positively FCR. Weight gain was similar among all treatments in EXP 1, whereas in EXP 2, WG was higher when 4 and 5.5% oil was included in the feed. RBO presented 94% fat metabolizability, and crude energy and metabolizable energy levels of 9.260 and 8.714 kcal/kg, respectively. Carcass yield was not influenced by oil type; however, oil inclusion level negatively affected breast yield. The experimental treatments had no effect on meat oxidative stability. RBO can be used as an alternative to soybean oil in broilers diets.

Comparison of the effects of semi-refined rice oil and soybean oil on meat oxidative stability, carcass yield, metabolism, and performance of broilers

Two experiments (EXP 1 and EXP 2) were conducted to compare soybean oil (SO) and semi-refined rice oil (RBO) added to broilers diets. In EXP 1, 400 male Ross x Ross 308 broilers were reared in battery cages, and their performance was evaluated. A metabolism assay was performed. In EXP 2, 1344 broilers from the same strain were reared in floor pens with rice husks litter. In addition to performance, carcass yield and meat oxidative stability were evaluated. In both EXP, birds were distributed in a 2x4 factorial arrangement, with two types of oils (SO or RBO) and four oil inclusion levels (1%, 2.5%, 4%, or 5.5%). Two periods were considered: starter (1 to 21 days of age) and grower (22 to 42 days). In both EXP, oil type had no influence on starter performance. Although treatments promoted similar in weight gain (WG) and feed intake (FI), grower birds fed RBO had better feed conversion (FCR) in EXP 2, but not in EXP1. In both trials, increasing dietary oil levels negatively influenced FI and positively FCR. Weight gain was similar among all treatments in EXP 1, whereas in EXP 2, WG was higher when 4 and 5.5% oil was included in the feed. RBO presented 94% fat metabolizability, and crude energy and metabolizable energy levels of 9.260 and 8.714 kcal/kg, respectively. Carcass yield was not influenced by oil type; however, oil inclusion level negatively affected breast yield. The experimental treatments had no effect on meat oxidative stability. RBO can be used as an alternative to soybean oil in broilers diets.