Abstract:

We studied dynamics of live weight and morphological composition of carcasses in Ross 308 chickens at 1-, 21-, 28-, 34-, 38- and 42-day ages when SUB-PRO probiotic was included in the diet instead of Maxus G feed antibiotic in amount of 100 g/ton of feed. By the age of 42, chickens in the control group (I) reached a live weight of 2234 ± 28.4 g, chickens in the experimental group (II) - 2329 ± 27.3 g, and chickens who took feed antibiotic (III) - 2320 ± 33.4 g. Live weight of chickens of the II group by the age of 42 days exceeded the I group by 95 g or 4.25 % (P ≤ 0.05), the III group - by 86 g or 3.85 %. In terms of carcass weight, the experimental group exceeded the control group by 4.60 % (P ≤ 0.05), group III - by 4.53 %. The meat productivity of chickens taking antibiotic was not studied further, since that had no practical significance. Over the entire period of rearing, the average daily gain in live weight in control chickens was 52.20 g, in the experimental chickens - 54.46 g. The relative muscle weight in broiler carcasses of the experimental group increased from 55.34 to 66.37 %v from 1 to 42 days of age, while the relative bone weight decreased from 33.23 to 16.78 %. By the age of 42, absolute muscle and bone weight had 123.47- and 51.91-fold increase, respectively, in comparison with diurnal weight. The data of anatomical cutting of chicken carcasses showed that, in terms of muscle and bone content, the most valuable were: breast - 84.63 and 8.25 %, thigh - 75.66 and 12.54 %, respectively; less valuable: drumstick - 67.86 and 20.98 %, wing - 50.58 and 33.53 %, respectively. Diameter of muscle fibers of superficial pectoralis muscle in 42-day-old broilers was 55.20 μm; water content - 75.10 %, fat - 1.60 %, protein - 22.31 %. In terms of microbiological parameters, carcass meat meets the requirements of GOST 31468-2012 interstate standard. The inclusion of SUB-PRO probiotic in chicken diet instead of antibiotic does not reduce productivity, but excludes the negative consequences of antibiotic use.

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