Index of biological value of broiler chicken meat after experimental feeding of antibiotic Danoxan-50
Authors:   National University of Life and Environmental Sciences of Ukraine, Tkachuk S. A. 
Published: January 2022

Among a number of antibacterial drugs, the share of fluoroquinolones used to treat bacterial infections is 25 % of the total number of pharmaceuticals available on the world market. Because fluoroquinolone antibiotics are low in toxicity, have a broad spectrum of antimicrobial activity and favorable pharmacokinetic properties. In particular, danofloxacin – belongs to the fluoroquinolone antibiotics and has no natural analogues, because it is made by artificial synthesis, and therefore does not cause addiction to pathogenic microorganisms. Danofloxacin mesylate (danofloxacin) is the main active ingredient of the new veterinary drug Danoxan-50, used in veterinary medicine for the treatment of respiratory and gastrointestinal diseases of cattle, pigs and chickens. However, poultry meat contains residues of antibiotics that change its microflora, which leads to negative effects on the end user. Scientists have proved that the products of poultry slaughter raised on poultry farms in Ukraine contain residual amounts of antibiotics: penicillin series, tetracyclines, streptomycin and some feed antibiotics – grisin, bacitracin and nisin. However, the increased demand for chicken food has led to the creation of crossbred broiler chickens with an increase in slaughter weight. This had a negative effect on the genetics of these animals, for example, on the occurrence of spontaneous idiopathic muscle abnormalities. In addition, the quality of poultry meat is affected by the age and period of molting, the use of feed additives in poultry feeding and chronic heat stress and oxidative stability of muscles. All of these factors can affect the quality of poultry. At the same time, the most important indicator of food quality is biological value, as an integral expression of their various properties: chemical composition, nutritional value, safety, biological activity, and determines the degree of compliance with optimal human needs. In the context of expert confirmation of the safety of meat with the use of antibiotics in the treatment of poultry is the level of its biological value, the amino acid composition of proteins. Thus, scientists have found a reverse trend in the ratio of essential to essential amino acids in the studied muscles (respectively – 25.2% and 6%), as well as identified an amino acid that limits the biological value of the protein - methionine. The aim of the study was to investigate the amino acid SPEED of broiler meat during experimental feeding of the antibacterial drug Danoxan-50. However, the increased demand for chicken food has led to the creation of crossbred broiler chickens with an increase in slaughter weight. This had a negative effect on the genetics of these animals, for example, on the occurrence of spontaneous idiopathic muscle abnormalities. In addition, the quality of poultry meat is affected by the age and period of molting, the use of feed additives in poultry feeding and chronic heat stress and oxidative stability of muscles. All of these factors can affect the quality of poultry. At the same time, the most important indicator of food quality is biological value, as an integral expression of their various properties: chemical composition, nutritional value, safety, biological activity, and determines the degree of compliance with optimal human needs. The material of the study was broiler chickens of the American cross "Cobb-500". To conduct the experiment, they were divided into 10 groups of 6 heads in each (1, 2, 3, 4, 5 experimental and 1, 2, 3, 4, 5 control). The experimental groups of birds were orally given the drug Danoxan-50 at a dose of 5 mg / kg for 5 days. The birds of the control group were given purified water. After slaughter for 24, 48, 72, 96 and 120 hours from broiler chickens selected experimental material – thigh muscles (quadriceps) and pectoral (large pectoral) in special bags with a lock, signed the material according to groups and dates of selection and frozen at a temperature of minus 20 ± 2 ° C. Calculated the biological value index or amino acid SCOR (ratio of the SCOR of the product protein to the SCOR of the reference protein) according to the FAO / WHO scale, according to the guidelines. Amino acid FAST is an indicator of the biological value of a protein, which is the percentage of a certain essential amino acid in the total amino acid content to the standard (recommended) value. According to the above indicators, 24 hours after slaughter, the limiting amino acid in the pectoral muscles of broiler chickens of the experimental group is leucine, and the control – valine. Instead, at 48, 72, and 120 hours after slaughter, the limiting amino acid in the pectoral muscles of broiler chickens is valine, both in the experimental and control groups. At 96 hours after slaughter in the pectoral muscles of broiler chickens of the experimental group, the limiting amino acid is valine, and in the control – leucine. At 24 hours after slaughter in the thigh muscles of broiler chickens, both the experimental and control groups, the limiting amino acid is leucine. Instead, at 48, 72 and 120 hours after slaughter, both the experimental and control groups, the limiting amino acid is valine. At the same time, at 96 hours after slaughter in the thigh muscles of broiler chickens of the experimental group, the limiting amino acid is leucine, and the control – valine. Leucine and valine are essential amino acids that are actively involved in the breakdown and synthesis of protein. Lack or absence of these amino acids in the body of birds and humans can lead to weight loss, stunted development and growth, as well as metabolic disorders. At the same time, leucine and valine are those amino acids that are part of the optimal amino acid composition in poultry diets and regulate protein synthesis in various tissues. Leucine induces muscle fiber expression and improves mitochondrial function through the Sirt1 / AMPK signaling pathway in skeletal muscle satellite cells. Also, the essential amino acid leucine is able to improve the quality of poultry meat, in particular its taste and aromatic characteristics. During 5 days of drinking the antibiotic Danoxan-50, the meat of broiler chickens contains an insufficient amount of leucine and valine, which reduces its biological value, which means that it can be attributed to low-quality foods. Broiler producers who treat poultry with this antibiotic should follow the instructions for its use, according to the withdrawal dates of danofloxacin mesylate - the active substance of the antimicrobial drug Danoxan-50.