Selection for Reduced Fear of Humans Changes Intra-Specific Social Behavior in Red Junglefowl—Implications for Chicken Domestication

The domestic fowl has a different social behavior compared to their ancestor, the red junglefowl. To examine whether selection for tameness has affected their intra-specific social behavior, 32 red junglefowl from two selection lines, one selected for increased tameness and one selected for a high fear of humans for ten generations, were kept in a group of two females and two males each and were observed in a semi-natural undisturbed enclosure. Birds selected for a low fear of humans had more social conflict, and the males from this selection crowed more and were more often observed in low social proximity to others. The high-fear birds spent more time close together with the rest of the group and performed more social, non-aggressive pecking. These results are consistent with known differences between ancestral red junglefowl and domesticated laying hens. Our results show that intra-specific social behavior has been affected as a side-effect of selection for increased tameness. This may have interesting implications for the emergence of the domestication syndrome in chickens.

In vitro behavior of Mycoplasmagallisepticum live-type nosode

As a step of a doctoral research project, in this study a live-type nosode was prepared from microorganism Mycoplasmagallisepticum strain R (ATCC 93-08/19610) according to Costa model and the rules by Brazilian Homeopathic Pharmacopoeia. Live nosode was tested in vitro to assess safety when used to immunize domestic fowl (Gallus gallus) against infection by this microorganism and to investigate its behavior under laboratory conditions. M. gallisepticum was not shown to grow in fluid (broth) and solid (plate) modified Frey medium with dilutions 11d, 12d, 20d and 30d. Inhibition halos about 2.0 mm were observed around paper disks impregnated with live-type nosode in microorganism-sown Petri dishes, whereas disks impregnated with conventional antibiotic oxytetracycline exhibited 8.0 mm inhibition halos. Protein assessment by Folin-Lowry method showed protein absence in dilutions 12d and 30d and neither microbial DNA traces were found in PCR assay in dilutions 12d, 20d and 30d.

Ornithodoros puertoricensis (Ixodida: Argasidae) Associated With Domestic Fowl in Rural Dwellings From Córdoba Department, Caribbean Colombia

Ticks of genus Ornithodoros are nidicolous parasites associated with a wide array of vertebrates. In humans, their bites cause hypersensitivity reactions and are capable to transmit pathogens of health concern. In the department of Córdoba, Caribbean region of Colombia, the first report of an Ornithodoros soft tick was made in 1980 by Betancourt, who described the collection of Ornithodoros talaje in human dwellings. Nevertheless, current the records of O. talaje made in South America have been questioned and likely correspond to misidentifications with morphologically similar species. Between October and December of 2020, we visited rural areas of four localities from three municipalities within the department of Córdoba: Cuero Curtido and Severá (municipality of Cereté), El Espanto (municipality of Planeta Rica), and Arroyo Negro (municipality of San Carlos). Search for soft ticks was performed in 46 human domiciles and peridomiciliary areas. We searched in areas frequented by domestic animals, inspecting cracks in the walls and fowl nests. Infestation by soft ticks was found in 13% (6/46) of visited houses. Overall, 215 ticks were collected (26 larvae, 144 nymphs and 45 adults) from nests of domestic birds or in the adjacent walls. Larvae, nymphs and adults were morphologically identified as Ornithodoros puertoricensis. Molecular identification of ticks was confirmed by sequencing the tick mitochondrial 16S gene of adults, pools of nymphs and larvae. Pairwise comparisons showed a 99% of identity with O. puertoricensis from Panama. This study reports for the first time O. puertoricensis associated with domestic fowl in rural dwellings in Colombia, and expands the geographical distribution of this tick species toward the Córdoba department. Importantly, local people described exposure to tick bites while sleeping in infested houses; therefore, the transmission of soft tick-borne pathogens is now of concern in the region.

The Biomass Reallocation Program

Underlying human-caused extinctions, past and present, is a vast biomass reallocation program. Before our Neolithic forebears began changing the world, biomass was distributed quite evenly among species of animals and plants. The tenure of humans has seen a marked change in this, as biomass became progressively concentrated into a small number of species—us and animals we eat. Today, 96% of all mammalian biomass consists in humans and the mammals that humans farm. An additional 70% of all avian biomass consists in domestic fowl. This biomass reallocation is the most significant driver of species extinction. The number-one driver of species extinction today is change in land use. The most significant driver of change in land use is agricultural expansion. By far the most prominent form of agricultural expansion is pastoral farming and the growing of animal feed crops. Eating animals is, therefore, the most important driver of species extinction.

Life Cycle and Genetic Identification of Argas persicus Infesting Domestic Fowl in Khyber Pakhtunkhwa, Pakistan

Ticks transmit numerous pathogens to animals including humans; therefore, they are parasites of health concern. Soft ticks infesting domestic fowl in Pakistan are carriers of viruses and bacteria and cause unestimated economic losses in the poultry sector. The current study was intended to identify soft ticks infesting domestic fowl and understand their spatiotemporal distribution along 1 year. A sum of 7,219 soft ticks were collected from 608 domestic fowl in 58 infested shelters; 938 (12.9%) ticks were found on the host and 6,281 (87%) in the shelters. The collected ticks comprised 3,503 (48.52%) adults including 1,547 (21.42%) males and 1,956 (27.09%) females, 3,238 (44.85%) nymphs, and 478 (6.62%) larvae. The most prevalent life stages were adults, followed by nymphs and larvae. Overall tick prevalence considering all visited shelters was 38.66% (58/150). The highest tick prevalence was found in district Lakki Marwat (50.03%) followed by Peshawar (31.08%) and Chitral (18.88%) districts. All ticks were morpho-taxonomically identified as Argas persicus. To determine their life cycle, adult A. persicus were reared in the laboratory infesting domestic fowl (Gallus gallus domesticus). The life cycle was completed in 113–132 days (egg to egg) with a mean temperature of 33 ± 3°C and relative humidity of 65 ± 5%. Individual ticks were used for DNA extraction and subjected to polymerase chain reaction (PCR) using specific primers for the amplification of a partial fragment of mitochondrial cytochrome oxidase subunit I (cox1) and 16S ribosomal RNA (16S rRNA) genes. Obtained amplicons were compared using basic local alignment search tool (BLAST) to scan for homologous sequences. Phylogenetic trees showed A. persicus from Pakistan clustering with conspecific sequences reported from Australia, Chile, China, Kenya, and the United States. This is the first study aiming to reproduce the life cycle of A. persicus and genetically identify this tick in the region. Further studies are encouraged to investigate the pathogens associated with this soft tick species in Pakistan.

Age-related changes of the histological structure in the limb bones of the domestic fowl

To assess the possibility of using the bird bone tissue as a recording structure, the histomorphological parameters of the bone tissue of laying hens of the lohman brown cross from the Kirov region (9 females and 1 male) aged from 1 month to 7.5 years were investigated. The comparison of the cross-sections of the humerus and femur, the phalanx of the toe and tibiotarsus of a 6-year-old individual revealed that tibiotarsus is the least susceptible to resorption. For further research in 7 individuals, this bone was divided into 3 sections (T1, T2 and T3), for each of which the description and measurement of the microstructure of the cross sections was carried out. It was revealed that the process of resorption of the periosteum begins at 2.5 years of age with the appearance of primary osteons. At the age of 3.5 years and later they penetrate into all layers of the periosteum, locating in chains between the lines of arrested growth. At 4.5 years of age, secondary osteons appear in the place of the primary ones, and areas of resorption are formed at the intersection of the Haversian and Volkmann canals. At the age of 5.5 years the medullary bone disappears from the bone cavity, rounded cavities filled with centripetal deposition of new bone tissue at the edges appear within the resorption sites. At the age of 6-7 years, bone tissue degeneration occurs, when the small cavities enlarge and merge into large resorption cavities, up to the complete resorption of the mesost. In the distal part of tibiotarsus (T3), a prolonged apposition of the layers of the periosteum and the latest resorption were recorded. The increase of the thickness of the periosteum and a decrease in the density of the osteon population was revealed by the morphometry of cross sections of the center of diaphysis. The sites of tibiotarsus where the age of females corresponds to the lines of growth layer of the periosteum were determined. The sites with additional lines of the arrested growth were demarcated. It was concluded that the periosteal layer of the domestic fowl tibiotarsus in the distal and proximal sites are suitable as a recording structure.