Comparative assessment of natural feed additives for functional effects on the digestive processes in the rumen of sheep (Ovis aries)

In ruminant husbandry, ergotropics, fungal cultures, modifiers, antioxidants, enzymes, and other feed additives with various biological properties help practitioners to create optimal conditions for ruminal microorganisms to grow and to digest various feed substrates of the diet. This paper first compares functional effects of bioactive natural substances (dihydroquercetin, organic iodine, micellar calcium, spirulina, and shungite) on the rumen digestion in Romanov sheep. The work aimed to investigate the peculiarities of the influence of natural feed additives different in their biological properties on fermentative and microbiological processes in the rumen of sheep. Dietary trials were performed in the conditions of the physiological yard, the Ernst Federal Science Center for Animal Husbandry, with Romanov sheep ( Ovis aries ). In 2014, 12 animals aged 4-5 months were assigned to four dietary treatments: a basal diet without supplementation (BD, the control animals), BD + shungite (0.3 % dry matter), BD + shungite (0.9 % dry matter), and BD + shungite (1.5 % dry matter). In 2018-2019, six fistulated sheep aged 2 years were fed according to two schemes. The first scheme of dietary treatment was as follows: BD for equalization, BD (control), dihydroquercetin (DHQ) (100 mg·head-1·day-1) + organic iodine (OI) (1.05 mg·head-1·day-1), BD for equalization, and DHQ (100 mg·head-1·day-1), each period lasted 14 days. In the second scheme, micellar calcium (M-Ca) injected into the rumen through a fistula (50 µl·head-1·day-1) was used instead of DHQ + OI, and spirulina (1.25 g·head-1·day-1, the dry powder mixed with 23.75 g filler) instead of DHQ. In all tests, at the end of each period, 3 hours after feeding, rumen contents were sampled to assess pH, redox potential (ROP), oxidization, total amount of volatile fatty acids (VFA), concentration of ammonia nitrogen, amylolytic activity, the biomass of ruminal protozoa and bacteria, and the microbial profiles. It was found that DHQ and spirulina have the most pronounced effect on ruminal pH, with a 12.7 and 9.5 % increase in the chyme pH, respectively. All dosages of shungite and M-Ca provide higher production of volatile fatty acids (VFA), the 20.6; 27.2 (р function show_eabstract() { $('#eabstract1').hide(); $('#eabstract2').show(); $('#eabstract_expand').hide(); }