The main objective of this study was to verify the safety of mealworm meal in the feed of laying hens from 17 to 42 weeks of age. Therefore, the feed mixtures were tested in terms of microbiological stability, fungal and mycotoxin content and selected parameters of hens’ intestinal morphology and physiology were monitored. The experiment was carried out with 30 Lohmann Brown Classic hens. Hens were divided by body mass into three equal groups with 10 replicates per treatment. The two experimental groups received feed mixtures containing 2% and 5% yellow mealworm (Tenebrio molitor L.) meal. The third group was a control group which had 0% of mealworm meal in the diet. Diets with 2% and 5% of mealworm meals did not affect the length of villi and microbiome of the caecum. The highest digesta viscosity from the ileum was found in the group with 5% mealworm, which may indicate a slower passage of the digesta through the digestive tract. Based on our results, it may be concluded that the proportion of mealworm meals does not deteriorate the quality of feeds. Mealworm meal does not negatively affect microbial stability in experimental feeds. Therefore, it can be recommended the two and (or) five percent of mealworm meal inclusion in hen’s diet.

The aim of the study was to identify the effect of fattening of experimental Simmental bulls (a total of 10 animals) with a high-concentrate diet on ruminal mucosa and dimensions of ruminal papillae, and to assess the intensity of keratinization of papillary epithelium. The experimental period lasted from weaning to slaughter (359 days). Histopathological and morphometric examinations of ruminal mucosa indicated that the ruminal papillae of bulls from the experimental group were better developed (long with a lower degree of keratinization) compared to the control group. Significant differences between the experimental and control groups were found in the length of ruminal papillae (p = 0.005), width of stratum corneum (p = 0.034) and degree of mucosal keratinization on the surface of ruminal papillae (p = 0.014). Conclusive results of morphometric analysis prove the facility of the use of morphometrics as a method useful for veterinary pathology, mainly for the accuracy of the histological diagnosis. Cattle, rumen, grain, morphometry, ruminal epitheliumThe rumen in young suckling ruminants is small, about half the size of the abomasum. It undergoes significant morphological and physiological changes during the growth of the animal. In cattle, the ratio between the rumen and abomasum of 4 week-old-calves is 1:2, at 8 weeks of age 1:1, at 3 months 2:1 and in the adult cattle 9:1 (Rosenberger 1964).The ruminal mucosa consists of a multilayer squamous epithelium with significant keratinisation. The lining has papillae of tongue-like shape on the surface with the length of 1-13 mm and width of 0.5-3 mm, and these significantly increase the surface of the ruminal epithelium (Hofmann and Schnorr 1982;Langer 1988;Frappier 2006). The longest papillae are located in the blunt sacs, at the bottom of the ventral sac and the bottom of the ruminal antrum. The length decreases towards the columns and on the edge there are only low papillae or they disappear completely (Jelínek 1995;König et al. 2004).The morphological properties of the gut lining including the size of papillae and their quantity are variable. The pathogenesis of morphological adaptation of the ruminal mucosa depends on several factors, such as age of the animal, composition and quality of feed, fibre content, and type, concentration and ratio of volatile fatty acids (VFA), ruminal content pH, intensity of fermentation processes in the rumen, etc. (Zitnan et al. 2003;Radostits et al. 2007). The ruminal papillae are rudimentary in newborn and young animals, therefore the mucosa is relatively smooth and pale (Jelínek 1995;Amaral et al. 2005). Under physiological conditions, mature papillae are covered with a thin layer of keratinising squamous cells (Frappier 2006). Morphology of the ruminal mucosa relates to concentrations of volatile fatty acids (VFA), mainly those of butyric and propionic acids. It is characterised by a process of continual changes, from regression to proliferation. The

The aim of the study was to identify the effect of supplementation of various forms of zinc on the ruminal mucosa and dimensions of ruminal papillae in 6-month-old goat kids. The experimental period lasted from weaning to slaughter (4 months). All 20 kids divided into four groups of five animals, were fed with the same feeding dose, which was different only in the quantity and form of zinc. Control group was without additional zinc supplementation (group A), the other groups were supplemented with zinc in the form of ZnO (group B), zinc in the form of chelate (group C) and zinc in the form of lactate (group D). Samples for histopathological and morphometric examination were collected after the slaughter of all animals from the bottom of saccus ruminis ventralis everytime from the same place. Significant differences were reported within the comparison of the length of ruminal papillae between groups B and C (P = 0.026) and B and D (P = 0.040), within the comparison of the width of ruminal papillae between groups A and D (P = 0.020) and within the comparison of the intensity of keratinisation of the mucosa of ruminal papillae between groups A and B (P = 0.034), A and C (P = 0.038) and A and D (P = 0.001). Histopathological and morphometric examination of ruminal mucosa indicated that the ruminal papillae of kids supplemented with zinc in the form of ZnO (group B) were better developed compared to the other groups. This result indicates better utilisation of the supplemented zinc in the form of ZnO. Forestomach, histometry, inorganic zinc, organic zinc, ruminantsThe ruminal mucosa consists of multilayer squamous epithelium with significant keratinisation. The lining has papillae of tongue-like shape on the surface, the height of which is 3-13 mm and width is 1-3 mm, and these significantly increase the surface of the ruminal epithelium (Hofmann and Schnorr 1982;König et al. 2004;Frappier 2006). The morphological properties of the gut lining including the size of ruminal papillae and their quantity are variable. It is characterised by a process of continual changes, from regression to proliferation. The pathogenesis of morphological adaptation of the ruminal mucosa depends on several factors (Zitnan et al. 2003;Amaral et al. 2005;Černík et al. 2011), including the effect of microelements. This includes cobalt, selenium, copper and also zinc (Arelovich et al. 2008;Eryavuz et al. 2009;Falhar et al. 2009).Zinc is a component part of various enzymes, nucleic acids, porphyrins, amino acids and proteins. As a stabiliser of cell membranes it ensures among other things also keratinisation of the surface layers of skin and some mucosal membranes, e.g. the oesophagus and rumen (Underwood and Suttle 1999; S u n et al. 2005). Zinc with other trace elements is added to feed mixtures for ruminants and pigs in order to stimulate growth and ensure good health condition and efficiency. It is supplemented in