Morphometric properties and distribution of alpha-actin in the smooth muscle cells (ASMA) of the small intestine during development in chicken.

The objective of this study was to investigate the morphological characteristics and expression of the α-smooth muscle actin (ASMA) immunohistochemistry during development of the small intestine in broiler chickens. Twenty-four healthy broiler chickens (ROSS 308) in 4 different age groups (6-, 14-, 28- and 52-day-old) were used in this experiment. A slight increase was observed in the weight and length of the duodenum, jejunum and ileum from days 6 to 28, peaked on day 52. The weight and length of jejunum on days 28 and 52, respectively, were significantly higher in female chickens compared with males (P < .05). An increase in height and width of propria and muscular layers of villi were obtained for the three segments during the experimental period. Villi height and width of jejunum in female broilers at day 28 were significantly larger than males (P < .05). These results also revealed that all the smooth muscle layers were immunoreactive positive for ASMA; but this reactivity differed between the muscle layers. The minimal expression of ASMA was observed at days 6 and 14 of age in circular and longitudinal muscular layers. At day 28, there was a more distinct expression of ASMA in circular and longitudinal muscular layers compared with days 6 and 14. Expression of ASMA in both muscle layers at day 52 was intensely immunopositive. Contractile function during the evolution of each organ and muscle layers could be dependent on different patterns of expression of ASMA in the smooth muscle cells. [ABSTRACT FROM PUBLISHER]