Evaluation of Age-Dependent Changes in the Coloration of Male Killifish Nothobranchius Guentheri Using New Photoprocessing Methods.

Fish as model objects have found wide applications in biology and fundamental medicine and allow studies of behavioral and physiological responses to various environmental factors. Representatives of the genus Nothobranchius are one of the most convenient objects for such studies. Male fish belonging to the family Nothobranchiidae are characterized by extremely diverse coloration, which constantly changes, depending on the age of the fish, environmental factors, and social hierarchical status. These fish species are characterized by a short life cycle, which allows changes in coloration, an indicator of the ontogenesis stage, to be estimated. Existing methods of fish color assessments do not allow the intensity of coloration of particular body zones to be clearly differentiated. In the present study, we suggest a method of two-factor assessment of specific fish body zones using modified methods of photofixation and image processing software. We describe the protocol of the method and the results of its application to different-aged groups of male Nothobranchius guentheri. The coloration of selected areas (i.e., red spot on the gill cover (RSGC), black border on the caudal fin (BBCF), and white border on the dorsal fin (WBDF)) differed significantly according to the size and age of the fish (p < 0.05). The data obtained suggest that N. guentheri can be a model for studying aging by the intensity of body coloration in males.

Probiotic biomarkers and models upside down: From humans to animals.

Probiotics development for animal farming implies thorough testing of a vast variety of properties, including adhesion, toxicity, host cells signaling modulation, and immune effects. Being diverse, these properties are often tested individually and using separate biological models, with great emphasis on the host organism. Although being precise, this approach is cost-ineffective, limits the probiotics screening throughput and lacks informativeness due to the 'one model - one test - one property' principle. There is а solution coming from human-derived cells and in vitro systems, an extraordinary example of human models serving animal research. In the present review, we focus on the current outlooks of employing human-derived in vitro biological models in probiotics development for animal applications, examples of such studies and the analysis of concordance between these models and host-derived in vivo data. In our opinion, human-cells derived screening systems allow to test several probiotic properties at once with reasonable precision, great informativeness and less expenses and labor effort.

Probiotic Intake Increases the Expression of Vitellogenin Genes in Laying Hens.

A promising approach for slowing down the rate of reproductive aging is the use of probiotic bacteria as a feed additive. In the current study was investigated the influence of the intake of a potential probiotic on the follicle content and expression of vitellogenin genes (vtg1, vtg2, vtg3) in aged hens. RNA was isolated from liver samples collected from 570-day-old laying hens and gene expression levels were measured using RT-PCR. Bacillus subtilis KATMIRA1933 supplementation had a positive effect on the number of formed follicles in hens and also triggered a significant increase in the relative expression levels of vtg1, vtg2, and vtg3. A Bacillus amyloliquefaciens B-1895 enriched diet or a combination of the two strains had a modest effect on both the number of follicles and the expression of vitellogenin genes. Additionally, the study demonstrates that vitellogenin mRNA expression levels can be considered as a biomarker in a convenient approach for analyzing the hen's egg-laying ability.

The Impact of Bacillus subtilis KATMIRA1933 Supplementation on Telomere Length and Mitochondrial DNA Damage of Laying Hens.

In the current study, we performed in vivo investigation of probiotic intake influence on nuclear and mitochondrial DNA damage of hens, using quantitative PCR techniques. The probiotic supplementation to the diet of Hisex Brown hens had no significant effect on the rate of telomere shortening. After prolonged probiotic intake (225 and 445 days), the 18-21% decrease in the mtDNA lesions was detected. Since avian mitochondrial DNA damage investigations are rare, the current study of the probiotic-enriched diet's impact on the damage of the hen mitochondrial DNA is novel and highly important. The decrease of mtDNA damage is a beneficial property, which could positively affect the reproductive aging of hens. The positive impact of probiotic supplementation on hens' performance traits such as hen-day egg production, egg weight and mass, and feed conversion ratio was observed.

Bacillus Probiotic Supplementations Improve Laying Performance, Egg Quality, Hatching of Laying Hens, and Sperm Quality of Roosters.

The study aims at elucidating the effect of bacilli probiotic preparations on the physiology of laying hens and roosters. Probiotic formulations were prepared as soybean products fermented by Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895. In this study, groups of male and female chickens were used. These groups received a probiotic preparation based on either B. subtilis KATMIRA1933 or B. amyloliquefaciens B-1895, or of a mixture of strains, from the first day to the age of 39 weeks. These preparations positively affected egg production, quality of sperm production, and quality and hatchery of eggs. Considering the simplicity and cost effectiveness of the soy-based probiotic preparation, these formulations should be considered as advantageous in modern livestock production.