Activity of digestive enzymes in duodenal chymus and blood in broilers of parental lines and the meat cross depending on dietary bioactive additives

The achievement of maximal productivity in poultry requires knowledge of the genetic productivity potential and adjustment of nutrition according to bird’s physiological peculiarities. It is well established that early growth and development in poultry depend on the functional formation of the digestive system. Exocrine function of the pancreas plays one of the most important roles in this process. Earlier studies showed that the weight of the pancreas in broiler hybrid chicks is substantially higher compared to the parental lines till 35 days of age. Detailed comparative investigation of the corresponding distinctions in the digestion, however, requires physiological studies on fistulated chicks. The aim of the study presented was to determine and compare the activities of digestive enzymes in duodenal digesta and blood in hybrid broiler chicks (cross Smena 8) and in chicks of parental lines (Cornish and Plymouth Rock) when using bioadditives of several types, i.e. a spore forming probiotic, the mixture of low molecular weight organic acids, phytobiotic complex Intebio, feed additive with living bacteria (ООО Biotrof, Russia). It was found that amylase activity in the duodenal digesta was 22.0 % higher in the hybrid and 35.8 % higher in Cornish parental line as compared to Plymouth Rock line; lipase activity was higher 5.8- and 2.3-fold, respectively, due to the high dietary level of crude fat. The activity of proteases, however, was significantly lower in hybrids (by 9.0 %, p < 0.05) as compared to Plymouth Rock line and 32.3 % higher when compared to Cornish chicks (p < 0.001). The activity of blood amylolytic enzymes followed the reverse trend compared to the duodenal digesta; activity of other blood enzyme bore no differences between the genotypes. A diet formulation, as a proportion of protein, fat, and carbohydrates, can substantially influence the activity of the digestive enzymes in the intestinal lumen and in blood. Low molecular weight organic acids and the enzyme-based preparation in the diets for meat-type chicken stimulate activity of digestive enzymes in the duodenal digesta and blood with respect to the genotypic physiological peculiarities of the birds.