Abstract. Due to the abuse of antimicrobial agents, microorganisms are increasingly showing resistance to antibiotics, which is a problem not only from a medical point of view but also from an economical perspective. Microbes acquire the ability to develop resistance to antibiotics, which puts the effectiveness of therapy in question. Therefore, there was an increased interest in substances found in plants, showing strong antimicrobial activity [Król et al. 2013, Lima et al. 2013, Różański and Drymel 2009, Grzesiak et al. 2018]. An effective natural alternative are essential oils. These natural plant extracts find their application in medicine, cosmetology, food industry [Herman and Herman 2015, Kaniewski et al. 2016] and in animal nutrition [Radkowska 2013]. In addition to the effect of better feed utilization, essential oils are also useful in the treatment and prevention in various animal species [Crowell 1999].
Magdalena Jedrzejczak-Silicka, Yu-Hsiang Yu, Yeong-Hsiang Cheng, Andrzej Dybus
Abstract. The LDHA/HaeIII polymorphism (g.2582481G>A) in pigeons is associated with physiological predispositions for rapid return and endurance, which are one of the most desired racing performance traits. Thus, the aim of the study was to analyse the association between the g.2582481G>A polymorphism with the relative expression level of LDHA in the group of young homing pigeons. The results demonstrated differences, but not significant in the relative LDHA expression level in the group of pigeons carrying different LDHA genotype. The highest expression of LDHA gene in pigeons carrying LDHAAG genotype was reported. Moreover, the differences in the average relative quantity of the LDHA gene were different in relation to gender, with a slightly higher expression level of the LDHA gene in females. In conclusion, the highest expression level of LDHA gene in homing pigeons with genotype AG may explain the better racing performance of LDHAAG pigeons reported in previous studies.
Abstract. We have studied the dynamics of growth and development of Hayseks Brown layer hybrids, from day 1 of age to peak egg production. During the experiment, the study of the intensity of metabolic processes in the body of 6, 35, 90, 120, and 150 day-olds, i.e. in critical periods when there is intense growth of feathers and juvenile molt (30–60 days), the beginning of the oviposition (120 days) and the beginning of an intensive egg production (150 days). In these age periods, the level of soluble proteins, amine nitrogen, and the activity of alanine and aspartate aminotransferases were determined in liver tissues, the mucous membrane of the proventriculus, duodenum and pancreas. As a result of the research, it was found that the intensity of the growth of chickens is different from the recommendation for the "Hayseks Brown" cross. Only at the age of 119–126 days growing the body weight of the reared chickens coincides with the recommended technology for hens of the cross "Hayseks Brown". During the growth of young birds, in the critical periods of growth and development, it is necessary to deliberately affect the processes of protein metabolism by enhancing the processes of digestion and assimilation of nutrients and biologically active substances of fodder.
Abstract. The study involved 448 Black-and-White Holstein-Friesian cows. All animals came from one herd, they were kept in the same barn and in the same environmental conditions. Complete phenotypic data on the studied animals was collected. The aim of the research was to search for possible associations between SNPs in the CXCR1 and IL6 genes and mastitis. Identification of specific SNPs was possible due to the use of the PCR-ARMS method. Statistically significant associations were found between the analysed SNPs and resistance to mastitis and selected milk production traits.