Impact of inulin and yeast containing synbiotic on calves' productivity and greenhouse gas production

Aim: The research aimed to determine the impact of synbiotic: 6 g of prebiotic inulin and 5 g of probiotic Saccharomyces cerevisiae strain 1026 on calves' productivity and greenhouse gas (GHG) production. Materials and Methods: The research was conducted with 10 Holstein Friesian and Red Holstein (Bos taurus L.) crossbreed calves of mean age 33±6 days and initial body weight 73.4±12.75 kg. We added the synbiotic into the diet of five dairy crossbreed calves (SynG) and five calves in control group (CoG) received non-supplemented diet. The duration of the experiment was 56 days. The weight of calves and amount of methane (CH4) and carbon dioxide (CO2) in the rumen were determined on day 1, 28, and 56. On day 56, three calves from each group were slaughtered. Meat samples were assessed for some indicators of meat quality. The main methanogens were detected in the rumen fluid and feces. Results: The weight gain during the whole experiment period of 56 days was higher in the SynG (62.6±13.75 kg) compared to CoG (36.8±7.98 kg) calves (p<0.01). There were no significant differences in the levels of protein (%), fat (unsaturated and saturated – %), and cholesterol (mg/100 g) in meat samples from both groups. At the end of the experiment, the amount of CH4 in calves' rumen in CoG was higher (Me=792.06 mg/m3, interquartile range [IQR] 755.06-873.59) compared to SynG (Me=675.41 mg/m3, IQR 653.46-700.50) group (p<0.01). The values for CO2 were also increased in CoG (Me=4251.28 mg/m3, IQR 4045.58-4426.25) compared to SynG (Me=3266.06 mg/m3, IQR 1358.98-4584.91) group (p=0.001). There were no significant differences in the calves' weight and certain methanogen species in rumen liquid and feces on the 56th day of the experiment. Significantly higher results in the parameter total prokaryotes (V3) (bacteria+archaea) in rumen fluid were in SynG, whereas significantly higher results in the parameter total methanogens Met630/803 in rumen fluid were in CoG, p