Effect of early feed restriction programs and genetic strain on humoral immune response production in broiler chickens.

Two experiments were conducted to compare the immunocompetence of Cobb high performance and rustic Label Rouge broilers and the influence of reduced growth rates subsequent to feed restriction on the IgY anti-bovine serum albumin (BSA) response. In the first experiment (EXP), 360 broilers were assigned to 36 cages from 1 to 42 days of age. A completely randomized design was applied in a 3 × 2 factorial arrangement, with 3 groups (Label Rouge, Cobb ad libitum, and Cobb Restricted Intake), and 2 levels of energy (3,100 and 2,800 kcal/kg); there were 6 replicates per treatment. In the second EXP, 384 Cobb 500 male broilers were randomly assigned to the following feed restriction programs from day 8 to 16: Control, fed ad libitum; Quantitative (80% of the control amount); By Time (fed for 8 h/d), and Qualitative (80% limiting nutrients) restriction. Blood samples were collected on days 35 and 42 (EXP 1) and weekly from day 7 to 42 (EXP 2) for IgY anti-BSA quantification. In EXP 1, the production of IgY anti-BSA was lower in the Cobb groups (P < 0.0001) than in the Label Rouge group, and higher in the Cobb Restricted Intake group (P < 0.0001) compared with the same genetic strain fed ad libitum. Birds fed the low energy diet presented lower (P ≤ 0.06) IgY anti-BSA, independent of genetics. In EXP 2, no difference (P > 0.05) was observed 1 wk after the first BSA inoculation. However, at day 28, birds in all feed restriction programs had higher (P < 0.05) IgY anti-BSA than the Control group fed ad libitum. At day 35, the greatest residual effect of IgY anti-BSA was observed in the Quantitative restriction group. No differences (P > 0.05) were observed between groups after 42 d. The 3 early feed restriction programs had beneficial effects on the humoral immune response. Overall, Quantitative restriction promoted a longer lasting IgY anti-BSA response. Lower growth rate, due to feed restriction or genetic potential, improves humoral immunity in broiler chickens.

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.

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 CLA on performance and immune response of weanling piglets.

An experiment was conducted to evaluate the effect of CLA on the immune response and performance of piglets when subjected to an immune challenge. A total of 32 weanling pigs (17 to 23 d of age) with an initial BW of 8.9 kg were allotted to a 3 × 2 factorial arrangement of treatments. There were 3 levels of dietary CLA (0%, 1%, and 2%) and 2 levels of lipopolysaccharide (LPS) challenge (unchallenged and challenged). Challenged pigs were challenged on d 7 and 21. On d 4 and 18, all pigs were inoculated with BSA for assessment of IgG production. There was no difference in growth performance among piglets receiving different CLA supplementation levels. However, LPS-challenged piglets had poorer BW (P < 0.05), ADFI (P < 0.01), and ADG (P < 0.001) compared with the control group at d 35 postweaning. Lipopolysaccharide-challenged piglets also had increased respiratory rate (P < 0.001) and rectal temperature (P < 0.001), and decreased plasma proteins, hematocrit, and white blood cell counts (P < 0.05). Production of IgG against BSA was increased in the 1% CLA supplementation group (P < 0.001), indicating that CLA has an immunomodulatory effect. Supplementation with CLA did not affect lymphocyte proliferation, percentage of CD4(+) and CD8(+) cells, plasma proteins, red and white blood cell count, respiratory rate, or rectal temperature after LPS challenge. Although CLA supplementation did not influence growth performance or certain immune system measurements, the increased IgG titers with 1% CLA dietary supplementation indicate that it has a beneficial effect on the humoral immune system of weaned piglets.