Use of phytochemicals in cattle feeding (review)

The use of feed antibiotics is the most common way to stimulate the growth and increase productivity of animals used for food production. However, the irrational use of antibacterial drugs in the feed industry is becoming a key reason for the persistence of residual amounts of antibiotics in animal products and the development of antibiotic resistance in pathogenic microorganisms. The problem of antibiotic resistance is one of the main ones in the world, since the emergence of bacterial resistance mechanisms to antibiotic compounds leads to a decrease in the effectiveness of treatment of infectious diseases in both animals and humans who consume animal products (H. Hao, et al., 2014). The use of phytochemicals (phytobiotics, PB), the secondary plant metabolites terpenoids, alkaloids, and phenolic compounds (A. Bernhoft, 2010) in feeding ruminants, especially cattle is an alternative to antibiotic growth stimulants (S. Reddy et al., 2022) and s the taste and attractiveness of the diet (S.F. Sukhanova et al., 2015). PB effectively affect the cell membranes of pathogenic microorganisms due to lipophilicity and small size of active molecules (S. Burt, 2004). This ability leads to disorganization of the cellular structures of prokaryotes and inhibition of quorum sensing processes, which prevents the spread of infections and improves the overall microbiota of the intestinal tract (A. Ultee et al., 2000; K.S. Kondrashova et al., 2020). The purpose of this work is analysis of the global practice of using phytobiotic drugs in cattle feeding and to summarize the metabolic effects they mediate in connection with the chemical structure of their constituent molecules. According to research data (M.J. Groot et al., 2011; M.E.N. Soroor et al., 2015), PB contribute to a decrease in the number of methanogenic and ammonia-producing bacteria in the rumen, resulting in a decrease in greenhouse gas emissions. PB has a positive effect on increasing the total bacterial mass in the rumen (M. Wanapat et al., 2008). A richer and more diverse microbiome improves the fermentation of feed, contributing to the efficient extraction of nutrients. This leads to a more complete breakdown of fiber and other complex carbohydrates contained in the diet, and, as a result, increases the digestibility and digestibility of nutrients (M. Tajodini et al., 2014), growth rates and immune status of animals (A. Rahal et al., 2012). Some secondary metabolites can regulate the hormonal production of the ovaries (R. Kumar et al., 2013), increase milk production, prevent udder infection (S. Kumar et al., 2008), and improve the reproductive performance of cows (R. Kumar et al., 2013). Moreover, phytochemicals have antiinflammatory properties (F. Muanda et al., 2011) and antioxidant properties (C.A. Rice-Evans et al., 2003). They can inhibit peroxidation of membrane lipids, chelate metals and stimulate the production of antioxidant enzymes (S. Calsamiglia et al., 2007), contribute to the fight against free radicals and oxidative stress, which can negatively affect the health and productivity of animals. However, the efficacy and safety of the use of PB depend on many factors (D. E. Cross et al., 2007; Y. Yang et al., 2009), which requires a more detailed and comprehensive study of such growth metabolites.