Investigating adverse effects of chronic dietary exposure to herbicide glyphosate on zootechnical characteristics and clinical, biochemical and immunological blood parameters in broiler chickens

Although the herbicide glyphosate is widely used globally and considered safe, more evidence of its adverse effects on animals and humans is accumulating. The present investigation was aimed at evaluating the impact of different glyphosate concentrations on zootechnical characteristics and clinical, biochemical and immunological blood parameters in Ross 308 broiler chickens. Four groups were employed, including untreated control and three experimental groups fed diets enriched with glyphosate at doses of 10, 20 and 100 ppm that conformed to 0.5, 1 and 5 maximum residue limits, respectively. The results showed that glyphosate is a stress factor triggering a multifaceted effect on important blood parameters (e.g., white blood cell and phagocytic counts), which was shown for the first time in the experiments involving productive meat-type poultry. It was first revealed that glyphosate-induced changes in blood parameters may be related to a negative impact on the zootechnical characteristics including the digestive tract organ development and body weight gain. The study findings suggested that exposure to glyphosate in the feedstuffs can adversely affect the physiological condition and productivity of broilers.

Features of Fractal Conformity and Bioconsolidation in the Early Myogenesis Gene Expression and Their Relationship to the Genetic Diversity of Chicken Breeds

Elements of fractal analysis are widely used in scientific research, including several biological disciplines. In this study, we hypothesized that chicken breed biodiversity manifests not only at the phenotypic level, but also at the genetic-system level in terms of different profiles of fractal conformity and bioconsolidation in the early myogenesis gene expression. To demonstrate this effect, we developed two mathematical models that describe the fractal nature of the expression of seven key genes in the embryonic breast and thigh muscles in eight breeds of meat, dual purpose, egg and game types. In the first model, we produced breed-specific coefficients of gene expression conformity in each muscle type using the slopes of regression dependencies, as well as an integral myogenesis gene expression index (MGEI). Additionally, breed fractal dimensions and integral myogenesis gene expression fractal dimension index (MGEFDI) were determined. The second gene expression model was based on plotting fractal portraits and calculating indices of fractal bioconsolidation. The bioconsolidation index of myogenesis gene expression correlated with the chick growth rate and nitric oxide (NO) oxidation rate. The proposed fractal models were instrumental in interpreting the genetic diversity of chickens at the level of gene expression for early myogenesis, NO metabolism and the postnatal growth of chicks.

Unraveling signatures of chicken genetic diversity and divergent selection in breed-specific patterns of early myogenesis, nitric oxide metabolism and post-hatch growth

Introduction: Due to long-term domestication, breeding and divergent selection, a vast genetic diversity in poultry currently exists, with various breeds being characterized by unique phenotypic and genetic features. Assuming that differences between chicken breeds divergently selected for economically and culturally important traits manifest as early as possible in development and growth stages, we aimed to explore breed-specific patterns and interrelations of embryo myogenesis, nitric oxide (NO) metabolism and post-hatch growth rate (GR). Methods: These characteristics were explored in eight breeds of different utility types (meat-type, dual purpose, egg-type, game, and fancy) by incubating 70 fertile eggs per breed. To screen the differential expression of seven key myogenesis associated genes (MSTN, GHR, MEF2C, MYOD1, MYOG, MYH1, and MYF5), quantitative real-time PCR was used. Results: We found that myogenesis associated genes expressed in the breast and thigh muscles in a coordinated manner showing breed specificity as a genetic diversity signature among the breeds studied. Notably, coordinated ("accord") expression patterns of MSTN, GHR, and MEFC2 were observed both in the breast and thigh muscles. Also, associated expression vectors were identified for MYOG and MYOD1 in the breast muscles and for MYOG and MYF5 genes in the thigh muscles. Indices of NO oxidation and post-hatch growth were generally concordant with utility types of breeds, with meat-types breeds demonstrating higher NO oxidation levels and greater GR values as compared to egg-type, dual purpose, game and fancy breeds. Discussion: The results of this study suggest that differences in early myogenesis, NO metabolism and post-hatch growth are breed-specific; they appropriately reflect genetic diversity and accurately capture the evolutionary history of divergently selected chicken breeds.

PSXVI-24 The succession of reindeer’ rumen symbiotic bacteria

Reindeer digestion is impossible without the symbiotic microorganisms that live in its rumen. The composition of plant fibers present in the diet of reindeer is characterized by an increased content of plant fiber, hemicellulose, lignin, and secondary lichen metabolites. The Arctic is characterized by extremely scarce food resources even in summer. In winter the nutritional value of the diet is further reduced. The digestion of such feeds is provided only by the enzyme systems of microorganisms that live in the rumen of ruminants. Therefore, the purpose of our study was to determine the changes occurring in the composition of the reindeer’ rumen bacterial community inhabiting the Nenets region of the Russian Arctic. Rumen contents were collected from 20 reindeer in winter and summer 2017. To identify the bacterial community, 16S rRNA sequencing was used on the MiSeq (Illumina). Statistical processing of the results of NGS using the PERMANOVA analysis showed that the rumen bacterial communities in winter and summer have significant differences (P = 0.001). Taxonomic analysis using the GreenGenes database showed that, in general, at the phylum level in the community, representatives of Firmicutes (29.98–52.67%) and Bacteroidetes (33.55–51.87%) dominated. Significant differences were shown for microorganisms associated with the fermentation of plant polysaccharides. In winter, a significant increase in bacteria of the genera Succiniclasticum (P < 0.001), Paraprevotellaceae (P < 0.001), Coprococcus (P < 0.001), Butyrivibrio (P < 0.001), Prevotella (P < 0.001), Ruminococcus (P < 0.001). Thus, there is a succession of the bacterial community of the reindeer rumen associated with the change of seasons, affecting minor groups of microorganisms. In turn, it is associated with the availability of various components of the diet and the predominance of more or less easily digestible substances in it. The study was supported by a grant of Russian Science Foundation Project No. 17-76-20026.