Wpływ wybranych dodatków paszowych stosowanych w profilaktyce kokcydiozy na profil histologiczny oraz właściwości fizykochemiczne mięśni piersiowych kurcząt szybko i wolno rosnących

The aim of the study was to determine the effect of selected in-feed coccidiostats (ionophore coccidiostat monensin and plant coccidiostat) on the histological profile and physicochemical properties of breast muscles in fast and slow-growing chickens. The experiment was carried out with 480 fast-growing Hubbard Flex chickens kept until 42 days of age, and 480 slow-growing Hubbard JA 957 chickens raised until 63 days, which were divided into 3 feeding groups. The control group (K) received standard feed mixtures without additives. The mixtures for experimental groups also contained a complementary feed in the form of plant coccidiostat (A) or ionophore coccidiostat monensin (M). The highest body weight at 42 and 63 days was found in the group of birds receiving the plant coccidiostat (2548 and 3582 g, respectively). There was a tendency for higher feed consumption in group A birds characterized by the highest body weight at the end of rearing. Statistical analysis showed significant differences in the mortality of fast and slow-growing chickens. Mortality ranged from 1.82 to 5.72% in fast-growing chickens, and from 2.60 to 4.33% in slow-growing chickens. The use of different coccidiostat additives in the diet of chickens that were raised until 42 and 63 days of age had no significant effect on dressing percentage. The results of histochemical examination showed that slow-growing chickens were characterized by a greater diameter of breast muscle fibers compared to fast-growing chickens. The greater proportion of large-diameter fibers had a significant effect on increasing water holding capacity. The best water holding capacity was observed in the control group and in birds receiving the plant coccidiostat in their diets. Owing to the fact that active substances of plant origin do not require a waiting period, unlike the ionophore coccidiostats, they may be applied during the entire rearing period. In particular, these additives play a significant role in the maintenance of health status and welfare of chickens at a time when consumers expect food products free of pharmacological preparations.