This study aimed to characterize microsatellites in the rabbit genome using an in silico approach and to develop and validate microsatellite markers. Blood samples were collected from 15 Baladi rabbits and 18 New Zealand White (NZW rabbits). The GMATA software was used to define SSRs in the extracted sequences. Twelve primer pairs were used to validate the loci identified and the primers developed. The total number of the detected microsatellite loci overall chromosomes was 1,136,253. The di-nucleotide microsatellite repeats dominated and exceeded 88% of the detected microsatellites in all chromosomes. There were no microsatellites detected in mitochondrial DNA. The highest relative microsatellite abundance was obtained for chromosome 19, followed by 13 and 6. The highest estimated SSR density was obtained for chromosome 14, and the lowest was for mitochondrial DNA, followed by chromosome 13. The polymorphism was 81.63% and 75.51% for Baladi and NZW rabbits, respectively. The number of detected alleles ranged between two and seven alleles/loci, and polymorphic information content was from 35% to 71%. The AMOVA analysis showed that the total variance of all levels of population structure was 15.734. The results definitely confirmed higher genetic diversity in Baladi compared with NZW rabbits.

This review paper provides a systematized information of the species diversity, agrotechnical traits, growing methods, storage practices, and ways to use the main forage crops. It considers traditional grasses and legumes, as well as cereal crops that are used for silage and hydroponic fodder production. Special focus is made on highly advanced technologies from hydrophonic systems up to a range of fermentation technologies alongside genetic improvements that improve production while advocating environmentally friendly livestock rearing. This review also includes a local view of forage production in Bulgaria, considering the regional climate, farming conditions, and social and economic challenges. It also reveals forages' potential role for enhancing a more sustainable livestock sector by improving animal performance while decreasing carbon footprint levels alongside helping rural areas be stable as well as productive. Special focus is made on genetic variability alongside breeding potential in forages based on insights from some recent studies pointing out genotypic variation alongside heritability for effective selection.

Rabbit breeding is a highly intensive production industry. Rabbit meat is characterized by specific taste and qualities. Due to its composition, it is considered to bring many health benefits to the people. The microclimate in rabbit farms is critical to animal health, productivity and welfare. In order to achieve optimal production from rabbits, suitable environmental conditions must be created by controlling temperature, humidity, lighting, noise, air quality, water and food. In recent decades, the use of biologically active supplements in different branches of animal husbandry has increased. Biologically active supplements have natural origin, are safe and have proven positive effects on farm animals. They are easy to grow, and are also a renewable and sustainable source of beneficial ingredients in animal nutrition. Such supplements are probiotics, ferments and medicinal herbs. Biologically active substances are known to restore and maintain the balance of intestinal microflora, to improve the functions of immune system and to improve the overall health of farm animals. Another desirable effect of the diet supplements, such as the medicinal plant Yucca schidigera supplementation and different types of probiotics, is the ability to reduce ammonia levels in the produced manure. Diet supplements are easily applicable, by adding the extracts to the fodder or bedding of farm animals.

This study aimed to investigate the genetic polymorphisms in Agouti signaling protein (ASIP) and melanocortin 1 receptor (MC1R) genes and their association with coat color in native Bulgarian sheep breeds. A total of 247 individuals belonging to 7 native sheep breeds from 38 herds were genotyped for the ASIP and MC1R genes. Five single nucleotide polymorphisms (SNPs) were de-tected in the MC1R gene and three haplotypes representing MC1R ED and E+ alleles were identified among the studied sheep breeds. It was found that the dominant ED allele of MC1R is absent in the breeds - Patch-faced Maritza and Dubenska. The most common haplotype (h3) of the domi-nant ED allele was associated with either black or brown coat color in native Karnobatska, Kara-kachanska and Cupper-red Shumenska breeds, respectively. We can infer that haplotype 3 alleles could be a possible result that could interpret the mechanisms of black wool colour manifestation in the native Karnobatska sheep breed, which has formed the genetic pool of this sheep breed.

The growth performance of rabbits can be influenced by various dietary and environmental factors, including food supplements and ammonia levels in the rabbit barn. This study was conducted in order to investigate the impact of Mojave yucca (Yucca schidigera) supplementation on the ammonia levels, the growth development, blood parameters and carcass traits. Two groups of 30 rabbits in each were used in this experiment. First group (control) was fed with standard pelleted feed, and the second (experimental) was fed with pelleted fodder containing Yucca schidigera. The live weight and feed intake of rabbits were determined weekly for both groups. At the end of the experiment, blood samples were taken for hematological and biochemical analysis and six rabbits from each group were selected and slaughtered for determining carcass parameters. Ammonia levels, temperature and humidity were recorded at the same day of weight measurement. Results indicated that the inclusion of Yucca in the rabbits' diet led to a significant reduction in environmental ammonia concentrations (p<0.001). Furthermore, the inclusion of yucca powder significantly decrease feed intake of rabbits for the whole experimental period by 8.1 %. In the experimental group feed conversion ratio was lower by 15.3 % compared to the control group (p<0.05). Hematology test proved statistically lower degree of basophils in the experimental group (p<0.05). According to the biochemical parameters it could be summarized that urea (p<0.001) and AP (p<0.05) levels were significantly lower in the experimental group.