Porcentagem de parênquima e índice apoptótico da bolsa cloacal em frangos de corte em ambiente de conforto e estresse térmico

Abstract

Noventa e seis pintos de corte foram mantidos em diferentes temperaturas ambientais (calor, 29ºC; neutro, 24ºC; frio, 15ºC) e oito aves de cada grupo de temperatura (tratamento) foram sacrificadas nos dias 1, 7, 14, 21, 28, 35 e 42, e suas bolsas cloacais (BC) coletadas e processadas segundo técnica de rotina para inclusão em parafina. Cortes de 4m m, corados em HE, foram submetidos à análise histométrica utilizando-se o programa Kontron KS300, V 2.0. De cada corte foram mensurados a porcentagem de parênquima e o índice apoptótico nas BC. As médias da porcentagem de parênquima nas BC das aves com cinco semanas foram significativamente menores quando mantidas em ambiente frio (53,0%), quando comparadas com as do ambiente neutro (78,5%). As médias do índice apoptótico foram significativamente maiores nas BC de aves mantidas no ambiente frio (0,26), em relação às do neutro (0,12). Conclui-se que o estresse térmico induz apoptose de linfócitos e, conseqüentemente, hipotrofia da bolsa cloacal, alterando sua maturação.

Histomorphology of bursa of Fabricius: effects of stock densities on commercial broilers

“…This result indicates that, at this age, the immune system of broilers housed in low stocking density is able to react faster to infectious challenges. This was also demonstrated in broilers submitted to heat and cold stress, which the percentage of cortical area in bursal follicles was significantly reduced, evidencing the effects of temperature on the bursa (Guimarães et al, 2001). On the other hand, there was no significant difference between stocking densities of 15 and 20 birds/m 2 , which indicated that the immune potential of broilers reared under both densities is not different.…”

“…Today, it is known that the process of lymphoid tissue depletion is mediated by intensification of the programmed cell death -also known as apoptosis -mainly in the bursa of Fabricius, and this is why it has become one of the most important organs for studying this type of cellular death in poultry lymphoid systems (Paramithiotis & Ratcliffe, 1994). Studies on the bursa of Fabricius in poultry submitted to heat and cold stress or thermal comfort conditions concluded that thermal stress affects the development and maturation of the bursa, reducing the amount of parenchyma (Guimarães et al, 2001). Furthermore, thermal stress increases the index of lymphocyte apoptosis in the bursa of Fabricius in growing poultry (Guimarães et al, 2001).…”

“…Studies on the bursa of Fabricius in poultry submitted to heat and cold stress or thermal comfort conditions concluded that thermal stress affects the development and maturation of the bursa, reducing the amount of parenchyma (Guimarães et al, 2001). Furthermore, thermal stress increases the index of lymphocyte apoptosis in the bursa of Fabricius in growing poultry (Guimarães et al, 2001).…”

The impact of organic and inorganic selenium on the immune system of growing broilers submitted to immune stimulation and heat stress

“…There were no significant effects of Se levels or sources on absolute or relative spleen and bursa weights (Table 3), which is consistent with the findings of Laganá et al (2005) and Ribeiro et al (2008), in which the supplementation of ISe or OSe, as well as of Zn, with and without vitamins C and E, had no impact on these parameters. According to Guimarães et al (2003), broilers exposed to heat showed, at three weeks of age, higher cell death rates and hypotrophy in the bursa. In the present study, bursa weights were much lower than those reported before by Laganá et al (2005) and Ribeiro et al (2008), despite the fact that bursas were weighed in the present experiment one week later than the mentioned studies.…”

Evaluación De Dos Vacunas Comerciales Conteniendo El Complejo Antígeno Anticuerpo Contra La Infección Bursal en Pollos De Carne

“…De otro lado, las BF del grupo control no vacunado mostraron igualmente depleción linfoide moderada con calificaciones similares a los grupos vacunados, lo que podría deberse a una transmisión horizontal de una cepa de virus, por ser ubicuo y porque las condiciones de crianza no fueron de estricto aislamiento. También es importante indicar que esta prueba determina daño bursal que no es exclusivo del virus de Gumboro, pues factores de estrés y de agentes tóxicos de los alimentos pueden también causar un daño similar (Revidatti et al, 2001;Guimarães et al, 2003;PerozoMarín et al, 2003). Posterior al desafío, el IB de los grupos A y B fue menor que de los otros dos grupos, evidenciando atrofia a los 39 y 42 días de edad, lo cual coincide con los hallazgos de Haddad et al (1997).…”