А Formation of the biological value of beef protein depending on the age and breed of bulls

The article substantiates the expediency of assessing the content of essential amino acids in the samples obtained during the controlled slaughter of bulls for the protein of chicken eggs as an effective means of improving the quality of the management processes for producing biologically complete products. To ascertain the biological value of beef, samples of the longest back muscle were obtained from bulls of six domestic dairy breeds (Black-and-White, Red Steppe, and Angler dairy breeds and Simmental, Lebedyn, and Gray Ukrainian dairy breeds of combined productivity) at the ages of 3, 6, 9, 12, 15, 18, and 21 months. The experiments were conducted using the ion-exchange liquid column chromatography method on an automatic amino acid analyser (T-339 M) manufactured by Microtechna (Czech Republic). It has been demonstrated that the biological value of meat from bulls of the studied breeds is limited during ontogeny, primarily due to age-related factors. As bulls grow older and gain weight, their meat proteins exhibit increased biological value, approaching the reference index of chicken egg proteins. The first peak in the average values of the amino acid index in beef of bulls of 12 months of age (0.89%) was followed by a consistent decrease to 15 months (0.68%) and a repeated increase in values in animals of 21 months of age (0.83%). This is mainly due to the rise in the scores for methionine by 0.16%, isoleucine by 0.16%, histidine by 0.42%, arginine by 0.18%, and threonine by 0.20%. The increase in the biological value of the remaining amino acid scores in the age trend of changes did not exceed 0.15%. The identified patterns indicate the presence of additional reserves in the near-term scenario, which can be utilised to ensure the production of high-grade beef while optimising the age parameters of slaughtering bulls of different productivity directions.