Research note: methodology for high-quality RNA extraction from poultry whole blood for further gene expression analysis

Relationship of knob morphometric analysis with production performance and meat quality in Yangzhou goose (Anser cygnoides)

The development of the knob in Chinese geese (Anser cygnodies) is an outcome of extensive and prolonged selection and breeding. The knob serves not only as a visual indicator of sexual maturity in geese but also holds significance as a crucial packaging trait that attracts attention of consumers attentions, who tend to distinctly prefer geese with larger knobs. Consequently, investigating the formation of the knob holds practical value, as it will help achieving external traits aligned with consumers' preferences. To understand the relationship between knob size, production efficiency, and meat quality in Yangzhou geese, we examined histological and anatomical characteristics in 500- and 120-day-old geese with large and small knobs. Notably, knob size had a pronounced impact on key anatomical and structural parameters, such as chest depth, leg muscle water-binding capacity, and insoluble collagen composition in Yangzhou geese (p < 0.05). In addition, we measured testosterone and estrogen levels in male and female geese, respectively, as well as growth hormone, and found that birds of both sexes with a large knob had higher sex and growth hormone levels in the body. This study established a fundamental theoretical basis for advancing the enhancement of goose knob traits.

Recovery of RNA from avian nucleated whole blood stored under field conditions: an evaluation of commercial methods

1. Whole blood can be used to gain insights on several molecular mechanisms involved in animal physiology. However, its use to extract RNA from organisms that carry nucleated red blood cells is limited due to its high nuclease content and instability under field conditions.

2. Here, we evaluate three commercially available RNA preservation and extraction methods applied to avian whole blood samples kept in different storage conditions to identify the most suitable ones for use in field studies.

3. Whole blood starting volume was the most important factor; only samples with a starting volume of 50 µl yielded RNA whereas all 100 µl samples failed to provide any RNA regardless of the method used. RNA concentration decreased with storage time in every method employed. Samples stored at -20 °C yielded higher RNA concentration than the ones stored at 4°C although some possible effects of freeze-thaw cycles were observed.

4. For the two out of three methods it is likely that DNA contamination and/or extensive degradation of RNA could have taken place. Only whole blood stored and extracted using the Quick RNA Whole Blood kit provided high quality RNA in every condition tested.

Comfrey (Symphytum spp.) as an alternative field crop contributing to closed agricultural cycles in chicken feeding

Local cultivars of comfrey (Symphytum spp.) have been used to cover protein and mineral requirements of farm animals in low-input systems. Due to its known health-promoting (e.g. allantoin), but also anti-nutritive ingredients (e.g. pyrrolizidine alkaloids), multidisciplinary approaches are essential in order to quantify the nutritional value and the potential of its use in poultry and farm animals in terms of meeting animal needs, using local resources as well as remediating over-fertilized soils. Focusing on animal effects, here one-day old sexed Cobb500 broiler chickens were subjected to either a standard control diet or a standard diet supplemented with 4% dried comfrey leaves for 32 days. Performance traits indicate good acceptance of supplementation with comfrey leaves. Parameters for liver function, mineral homeostasis, bone mineral density as well as intestinal microanatomy revealed no signs of impairment. Quantified pyrrolizidine alkaloids were below the detection limit in liver and breast muscle (<5 μg/kg tissue). Comfrey supplemented male broiler chickens showed higher ash content in breast muscle and revealed altered gene expression profiles for metabolic pathways in blood cells. In healthy broiler chickens, the transcriptome analyses revealed no aberrations in the immune-related pathways due to comfrey supplementation. The results imply that the use of comfrey leaves in a high-performance broiler line seems feasible and offers the potential for closed nutrient cycles in site-adapted local agricultural systems. Further analyses need to focus on possible growth-promoting and health-improving components of comfrey and the safe use of chicken products for human consumption.

Heat shock protein B1 expression is associated with age at sexual maturity in Rhode Island Red and Punjab Red layers under heat stress

Heat shock proteins (Hsp) aid in protein folding and also to combat stress in all cellular organisms. HspB1 is a member of the small HSP family that has a significant role in thermo-tolerance. In this study, we aimed to determine the relationship (if any) between age at sexual maturity of layer poultry (Rhode Island Red and Punjab Red) and HspB1 expression both at mRNA and protein levels under heat stress. The mRNA expression of hspB1 was checked by real-time PCR. Delay in sexual maturity of the birds was found to be directly associated with the hspB1 mRNA expression in both the bird varieties under heat stress. No significant regression (association) of hspB1 mRNA expression with age at sexual maturity was observed in case of control, non-heat stressed birds. The serum levels of HspB1 were measured by indirect ELISA, using recombinant HspB1 that was expressed using pET-32b(+) vector in BL21(DE3) cells. Serum HspB1 concentration increased significantly (p ≤ 0.001) in heat-stressed birds as compared with control ones. A significant association was found between the increase in serum HspB1 concentration and delay in sexual maturity of all the birds under heat stress while no such association was found in control birds. In conclusion, HspB1 mRNA and protein expression were found to be associated with age at sexual maturity in Punjab Red and RIR layers under heat stress.

Co-infecting Reptarenaviruses Can Be Vertically Transmitted in Boa Constrictor

Boid inclusion body disease (BIBD) is an often fatal disease affecting mainly constrictor snakes. BIBD has been associated with infection, and more recently with coinfection, by various reptarenavirus species (family Arenaviridae). Thus far BIBD has only been reported in captive snakes, and neither the incubation period nor the route of transmission are known. Herein we provide strong evidence that co-infecting reptarenavirus species can be vertically transmitted in Boa constrictor. In total we examined five B. constrictor clutches with offspring ranging in age from embryos over perinatal abortions to juveniles. The mother and/or father of each clutch were initially diagnosed with BIBD and/or reptarenavirus infection by detection of the pathognomonic inclusion bodies (IB) and/or reptarenaviral RNA. By applying next-generation sequencing and de novo sequence assembly we determined the "reptarenavirome" of each clutch, yielding several nearly complete L and S segments of multiple reptarenaviruses. We further confirmed vertical transmission of the co-infecting reptarenaviruses by species-specific RT-PCR from samples of parental animals and offspring. Curiously, not all offspring obtained the full parental "reptarenavirome". We extended our findings by an in vitro approach; cell cultures derived from embryonal samples rapidly developed IB and promoted replication of some or all parental viruses. In the tissues of embryos and perinatal abortions, viral antigen was sometimes detected, but IB were consistently seen only in the juvenile snakes from the age of 2 mo onwards. In addition to demonstrating vertical transmission of multiple species, our results also indicate that reptarenavirus infection induces BIBD over time in the offspring.