Topinambūra koncentrāta un tā kombinācijas ar Saccharomyces cerevisiae ietekme uz teļu postnatālo attīstību = The effect of Jerusalem artichoke concentrate and its combination with Saccharomyces cerevisiae on the postnatal development of calves
Authors:   ,   Latvia University of Life Sciences and Technologies, Jonova Sintija 
Published: August 2022

Sintija Jonova's doctoral thesis “The effect of Jerusalem artichoke concentrate and its combination with Saccharomyces cerevisiae on the postnatal development of calves” was developed at: Saldus region, Jaunlutriņi parish, farm “Ratenieki”; Latvia University of Life Sciences and Technologies, Faculty of Veterinary Medicine, Preclinical Institute; Latvia University of Life Sciences and Technologies, Research Laboratory of Biotechnology, Division of Molecular Biology and Microbiology; Laboratory of the Veterinary Clinic of Latvia University of Life Sciences and Technologies; Latvia University of Life Sciences and Technologies, Faculty of Veterinary Medicine, Laboratory of Comparative Pathology of the Preclinical Institute and Institute of Food Safety Animal health and Environment “BIOR” from 2016 to 2021. The aim of this study was to determine the effects of feeding Jerusalem artichoke concentrate and its synbiotic with yeast (Saccharomyces cerevisiae strain 1026) on the health status and growth of calves, the morphofunctional development of the digestive tract, as well as methanogenesis in the rumen and large intestine during the transition from milk to solid feed. Objectives of the study 1. To study how the feeding of Jerusalem artichoke concentrate and synbiotic (Jerusalem artichoke concentrate and yeast Saccharomyces cerevisiae) can affect the health status, weight gain and economic benefits, as well as hunger and satiety in calves from 4 to 14 weeks of age. 2. To determine the effect of feeding the feed additives included in the 56-day study on the morphofunctional development of different parts of the digestive tract (rumen, abomasum, small and large intestine) during the transition from milk to solid feeding. 3. To evaluate the effect of Jerusalem artichoke concentrate and synbiotic feeding on the total amount of prokaryotes, including methanogenic microorganisms in the rumen and large intestine of 13 – 14-week-old calves. 4. To determine the effect of feeding the feed additives on the amounts of methane (CH4) and carbon dioxide (CO2) in the rumen of 4 – 14-week-old calves. The personal contributions are as follows: I performed an assessment of the animal health status, measuring the heart rate, respiratory rate, body temperature, evaluating the consistency of the faecal matter and analysing the haematological and biochemical parameters of the blood samples obtained. I also measured the animals, obtained rumen fluid and gas samples, measured the pH of the contents of different parts of the digestive canal, determined the mass of the various compartments of the multi-chambered stomach, obtained the necessary samples for histological analysis of the digestive canal structures (fixation, cutting, insertion in histology sample cassettes), conducted the microscopic examination of histological samples and analysed, presented and published the obtained results. The doctoral thesis is structured in five chapters: introduction, literature review, material and methods, research results and discussion. References contain 372 sources from the scientific literature. In the study, a total of 15 32±4-day old calves of both sexes of the Holstein Friesian black and white and red crossbreed were used. The effect of feeding Jerusalem artichoke concentrate (12 g) containing 48.5 – 50.1% of prebiotic inulin (hereinafter 6 g) and synbiotics (12 g Jerusalem artichoke concentrate with 5 g of S.cerevisiae yeast strain 1026) on: health status; live weight gain dynamics; morphofunctional development of the digestive tract; hunger and satiety, the amount of methanogenic microorganisms in the rumen and faeces; CH4 and CO2 production in the rumen of calves from 4 to 14 weeks of age. The following parameters were analysed in the study: basic health indicators of calves (heart rate, respiration rate, body temperature, fecal consistency, haematological and blood serum biochemical parameters); live weight of calves on specific study days and changes in live weight; the amount of ghrelin-immunoreactive cells in the abomasum and intestines; the pH of the internal environment in different parts of the digestive tract post-mortem; the absolute and relative mass of the forestomach, abomasum and entire stomach; micromorphometric parameters of the rumen, abomasum, small and large intestine; the total amount of prokaryotes, total methanogens and individual methanogenic species in the rumen and faeces; the amount of CH4 and CO2 produced in the rumen and the amount of these gases per kg of live weight. Feeding of the feed additives used in the dissertation study to calves from 4 to 14 weeks of age did not affect health status, as the basic physiological parameters, faecal consistency, as well as all determined haematological and biochemical blood parameters were within the age limits of the calves. Jerusalem artichoke concentrate at a dose of 12 g, which contains 6 g of the prebiotic inulin and synbiotic (12 g Jerusalem artichoke concentrate in combination with 5 g of S.cerevisiae yeast strain 1026) has been found to significantly improve calf live weight gain and promote the morphological development of different digestive canal structures, but did not affect the mass and relative mass of the multi-chamber stomach and its parts. Groups of calves fed feed supplements had significantly lower numbers of ghrelin-immunoreactive cells in the fundic region of the abomasum, but in the pyloric region of the abomasum, in the middle of the duodenum and jejunum, the number of these cells was not significantly different between the groups. Jerusalem artichoke concentrate at a dose of 12 g per calf per day did not significantly affect the rumen pH post-mortem, but the rumen pH results of the synbiotic calf group were significantly lower than those of the calf group that received 12 g of Jerusalem artichoke concentrate. Significant differences in pH level were also observed in the small and large intestine between the groups receiving the feed supplements and the control group of calves. Feed additives did not affect the incidence of methanogens Methanosphaera stadtmanae, Methanobrevibacter ruminantium and Methanobrevibacter smithii in calf rumen fluid and faeces, but the incidence of total prokaryotes in the rumen were significantly higher in the group of calves fed 12 g of Jerusalem artichoke concentrate than in the synbiotic group, while the incidence of total methanogens in the rumen was significantly lower than in calves of the synbiotic group. The feeding of Jerusalem artichoke concentrate (12 g) promotes the production of CH4 and CO2 gases in the calf's rumen, but feeding it in combination with 5 g of S.cerevisiae strain 1026 significantly reduces the production of these gases in the calf's rumen. There are 7 conclusions formulated in the conclusion part and 3 recommendations for practice. The doctoral thesis comprises 122 pages, 18 tables, 27 figures, and 3 appendices.