Investigating the Effect of using Microcapsule Essential Oil in Conditions of Flock Density on Performance, Morphology of the Small Intestine and Acidity of the Digestive Tract of Broiler Chickens

Today, the poultry industry tends to increase production per unit area, at the same time, the increase in flock density is faced with management and health restrictions and obstacles. Consuming medicinal plants can be an effective nutritional solution to overcome the challenge of high density. Therefore, an experiment was designed and conducted in order to investigate the effects of the essential oils of medicinal plants in two un-capsulated and microencapsulated forms in the diet on the performance, intestinal morphology and acidity of the digestive system of broiler chickens.

In this research, out of 250 broiler chickens of the Ross 308 strain in the form of a completely randomized design with a factorial arrangement of 2x2, with 4 treatments and 5 repetitions, and in each repetition, normal density of 10 chickens and high density of 15 chickens with a similar weighted average was used. Microcapsules containing essential medicinal plants containing effective compounds of thyme leaf, savory leaf, peppermint leaf and black pepper seeds developed in the Agricultural Biotechnology Research Institute of East and North-East region of Iran. The tested treatments were; The first treatment: normal density (10 chickens per square meter) + no plant essential oil (control), the second treatment: high density (15 chickens per square meter) + no plant essential oil, the third treatment: normal density (10 chickens per square meter) + 500 mg/kg of un-capsulated essential oil mixture, fourth treatment: high density (15 chicks per square meter) + 500 mg/kg of encapsulated essential oil mixture. The number of casualties, the weight of the casualties and the weight of the eliminated chickens were recorded separately. The amount of feed consumed and weight gain were measured weekly and the food conversion ratio was calculated. At the end of the experiment, 2 birds were randomly selected from each repetition and slaughtered after blood sampling. To study the structure of small intestine villi, samples were obtained from duodenum, jejunum and ileum. A microscope with 40 times magnification was used to measure the height and width of the villus, and a 100 times magnification was used to measure the depth of the crypt. The acidity of the caecum was measured by a pH meter.

The results showed that the addition of microcapsules led to a decrease in the percentage of losses, an increase in weight at high density compared to the absence of microcapsules. The use of microcapsules in conditions of high concentration led to a decrease in the oral conversion factor. Treatments using microcapsules in normal and high density conditions had significantly higher gastrointestinal acidity compared to treatments that did not receive microcapsules. Consumption of microcapsules in normal and high concentrations led to an increase in the length of intestinal villi.

It can be concluded that the addition of encapsulated essential oil improved the weight gain, feed conversion ratio, intestinal morphostructural characteristics.