The thesis presents the results of a study of the improvement of elements of the technology for growing spirulina biomass enriched with Sulphur, the study of harmlessness, acute toxicity and irritant effects of blue-green algae biomass enriched with Sulphur on white mice, white rats and rabbits, and the establishment of the effectiveness of introducing spirulina biomass with a high Sulphur content into the diets of young dogs.
The thesis was prepared at the Faculty of Biotechnology at Bila Tserkva National Agricultural University and is a part of the scientific topic ‘Development of biotechnologies of amino acid and mineral additives using the unicellular algae Spirulina platensis and Lucilia sericata larvae for calf rearing’ (state registration number 0124U000035).
The development and improvement of technologies aimed at the production of biologically active feed additives containing elements that belong to the essential nutritional factors, the use of which in animal feeding contributes to an increase in the conversion of feed into body weight that is an urgent scientific and practical issue. One of these feed additives is the biomass of the blue-green algae spirulina. Spirulina biomass contains up to 71.0 % protein on a dry matter basis. The algae's biomass contains fat-soluble and water-soluble vitamins and a wide range of important minerals. The biomass of Spirulina platensis in the body of animals has an immunomodulating, immunostimulating, antioxidant effect and the ability to influence metabolic processes.
Sulphur is an important mineral element in animal nutrition. The element is an integral component of the main sulphur-containing amino acids. The mineral is a part of enzymes, protein structures, and is involved in the synthesis of coenzymes, vitamins and hormones. Insufficient intake of Sulphur in the body is accompanied by metabolic disorders in animals.
Spirulina biomass is able to accumulate minerals from the nutrient medium in which it is grown, including sulphur. The technology for enriching spirulina biomass with sulphur hasn't been studied yet.
The scientific interest is to determine the toxicity of spirulina biomass enriched with sulphur and the effectiveness of its use in the rearing of young dogs.
During the implementation of the purpose of the scientific work, the following tasks have been solved:
– to establish the optimal source and dose of Sulphur at which the maximum growth of spirulina biomass takes place;
– to study the technological parameters of growing spirulina biomass in an environment with a high content of Sulfur;
– to investigate the chemical composition of spirulina biomass grown on a nutrient medium with a high content of Sulfur;
– to determine the acute toxicity of Spirulina platensis biomass enriched with Sulphur;
– to determine the irritating effect of Spirulina platensis biomass enriched with Sulphur;
– to study the effect of Spirulina platensis biomass enriched with Sulphur in the composition of the feed mixture on the growth of young dogs;
– to study the biochemical parameters in the blood of puppies under the influence of Spirulina platensis biomass enriched with Sulfur;
– to calculate the economic efficiency of the use of Spirulina platensis biomass enriched with Sulfur in puppy diets.
The experimental part has been carried out using modern and proven research methods: biotechnological, chemical, biochemical, haematological, toxicological, zootechnical, mathematical and statistical.
The applicant personally organised and carried out experiments to establish optimal doses, sources and technological parameters of enrichment of Spirulina platensis biomass with Sulphur, to study this biomass for harmlessness, acute toxicity and irritant effects in laboratory animals, to prove the effectiveness of using Spirulina platensis biomass with a high content of Sulphur in the diet of young dogs. He performed the analysis and statistical processing of digital data obtained by setting up experiments. The formation of the general scheme and purpose of the research, interpretation of the research results and their generalisation were carried out in consultation with the supervisor, Professor Serhii MERZLOV.
By studying the effect of different doses (from 250.0 to 900.0 mg/dm3) of Sulfur in the standard culture medium on the growth of spirulina biomass, it was found that during the phase of maximum biomass growth of the culture (6–9 days of the experiment) at the content of the element in the medium of 700.0 mg/dm3, the D index increased by 42.8 %. On the 16th day of cultivation (end of the experiment), at the highest dose of Sulfur in the culture medium (900.0 mg/dm3), it was found that excessive accumulation of Sulfur in cells accelerates their aging.
