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.

A total of 57 replacement gilts of the Danube White breed was used in a study carried out in the Agricultural Institute of Shumen. During the test period, for the trait “age at reaching 90 kg live weight” as well as the following traits, they were analyzed using a Piglog 105 device (portable ultrasound scanner, Frontmatec, Denmark): back fat thickness at points X₁ and X₂, growth intensity, back fat of m. Longissimus thoracis (LT), and lean meat percentage. DNA analysis was performed using the polymerase chain reaction restriction fragment-length polymorphism method (PCR-RFLP), with restriction endonuclease MspI. In the genotyped herd at the calpastatin gene locus, two alleles were identified with frequencies of 60% for allele D and 40% for allele C, and three genotypes DD, CC, and CD, with frequencies of 40%, 21%, and 39%, respectively. The percentage of animals with the DD genotype was the highest. They also had a lesser thickness of the back fat at point X₂, a larger back fat of LT, and a higher percentage of lean meat.

Cattle breeding is an important sector of agriculture, providing raw milk and milk products to constantly growing interest and demands of the consumers. Milk productivity is genetically determined, but this trait is also strongly influenced by environment. The genetic potential could be fully revealed only under optimal growing conditions. Identification of the genetic endowments and productive traits of farm animals, as well as the good production, is essential for any producer. Modern methods of molecular biology allow the usage of DNA markers in scientific research to identify genetic polymorphisms in gene loci and associate them with phenotypic traits. With the development of modern research in animal husbandry, it becomes possible to study the patterns of organization and function of the genome and to understand the mechanisms for the realization of genetic information in normal and pathological conditions. This data analysis was successfully applied in the development of breeding programs in animal breeding practice, aiming faster genetic progress. This review aims to follow the studies related to the evaluation of candidate genes related to milk productivity in dairy cattle. Lactation in mammals is a process that directly depends on the hormonal balance of organisms. Genetic variation in some genes such as Prolactin, Lactoferrin and Leptin has a reliable influence on the quantitative and qualitative characteristics of milk. Milk proteins are a large group of organic compounds important for the structure and normal function of the mammalian body. Specific to cow's milk are casein proteins, which come together in four forms (αS1-, αS2-, β- and κ-casein) and two whey proteins - α-lactalbumin and β-lactoglobulin. Genome-Wide Association Studies (GWAS), Transcriptomic Analysis, Whole-Genome Sequencing and PCR-RFLP are some of the modern methods for detecting genetic markers related to milk productivity. These approaches make it possible to find polymorphisms associated with desired productive traits.

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.

Poultry farming is an animal breeding industry addressing the need for eggs and meat with prominent delicacy qualities. Modern, highly productive breeds need to be created and maintained in order to let this industry meet the consumers’ demands. With the following literature overview we aimed to examine the studies evaluating the candidate genes that are related to birds’ productivity. Molecular-genetic approaches such as sequencing, Genome Wide Association Studies, Microsatellite markers, Real time PCR, PCR-RFLP enable the discovery of the genetic mechanisms that regulate the processes in organisms, thus affecting the desired productive qualities of farm animals. Meat and egg productivity directly depend on a number of genetic and non-genetic factors. The genetic factors include a wide variety of genes that control the expression of proteins involved in various biochemical processes