This work focused on analysing the content of selected sterols and profile of fatty acids of edible insect species – mealworm ( Tenebrio molitor ) and superworm ( Zophobas morio ), which are expected to increase their usability in human nutrition. Sterols content was determined using capillary...

With the growing public interest in edible insects, breeders are forced to increase the volume of production and shorten the life cycle of farmed insects. The exact composition of the feed is the know-how of each manufacturer. The aim of this work was to determine the general impact of individual conventional types of feed (bran, whey, raw ware potatoes) on the life cycle rate of Tenebrio molitor (TM), larval mortality and the content of fats, fatty acids and nitrogenous substances in larvae and their excrements. For the reasons of sustainability of the state of nature and waste disposal, polystyrene foam was added to the experiment as feed. The experiment was performed in two phases—rearing for 21 weeks and 5 weeks. The nitrogen content was determined using the Kjeldahl method (ISO 1871: 2009), the fat content by the Soxhlet method and the fatty acid profile using a gas chromatograph with a flame ionization detector (FID). The results of the work show that the basis of the TM feed is wheat bran, not only due to the observed low larval mortality (45% over 21 weeks) and their optimal nutritional value (nitrogenous substances 53.6% DM, fat 37.1% DM, the highest total fatty acid content) but also due to the higher speed of TM development. Lower larval mortality during rearing was found when feeding dried whey and raw ware potatoes, but the development cycle rate was low. This confirmed that the bran as a feed allowed a fast life cycle with good larval nutritional parameters. From a nutritional and reproductive point of view, TM appeared to be a suitable alternative to animal production. Polystyrene as a feed, tested for biodegradation by TM larvae, caused the highest larval mortality (75% in 21 weeks). However, the content of nitrogenous substances in the larvae increased to 69.77%, in the excrement, it even increased to 82.68%, and there was no cannibalism among the larvae. The work thus demonstrated the possibility of biodegradation of polystyrene using TM larvae with an increase in nitrogenous substances in both larvae and excrement.

The values of the temperature-humidity index and its influence on the performance parameters of dairy cows were monitored on four farms located in the southern part of the central Slovakia during a period of three years. The observed parameters included: the milk yield per cow per day, average milk speed and maximum milk speed. The thermal-humidity index was calculated based on a formula. The individual periods were divided according to the achieved THI. The results of dairy cows with a milk yield of 29 kg to 31 kg show that there is not a decrease in the milk yield per milking if the THI value is lower than 68. It was also found that there was a decrease in the milk yield per dairy cow in the robotic milking parlor for a THI value greater than 72. The influence of a THI value higher than 68 in these dairy cows results in a higher average milk speed, as well as a higher maximum milk speed. These two parameters are not yet in the main area of research interest. This study enriches the area with new knowledge, according to which dairy cows can show thermal stress by increasing the milk speed as well as the maximum milk speed.

The main objective of this work was to investigate the influence of environmental factors, including air temperature (AT), relative humidity (RH) and temperature–humidity index (THI), on the difference between rectal temperature (RT) and eye temperature (ET) of dairy cows. The monitoring of these parameters is important for the further possible introduction of digitalization in animal welfare, especially in dairy cattle. The mean calculated difference between rectal temperature and eye temperature (RT–ET) was 1.5 °C. The average value of AT was 16.4 °C, and the average value of RH was 59.2%. The average value of THI was 60.4. The results of the study showed that, for the temperature difference ET-RT, a low degree of correlation was found both with temperature and with the temperature-humidity index THI (R = 0.22; R = 0.23). However, the observed temperature difference of the animal (ET-RT) showed a moderate degree of dependence on the relative humidity of air (R = −0.32). Although the positive correlation coefficient for AT and THI points to the higher criticality of summer measurements, the negative correlation coefficient for RH supports the use of infrared thermography for determining the temperature of animals even in a moister barn environment.

Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis, the scientific journal of the Mendel University in Brno, Czech Republic