Domestic Animal Production Research Articles

Oral administration of olaquindox negatively affects oocytes quality and reproductive ability in female mice.

As an effective feed additive in the livestock industry, olaquindox (OLA) has been widely used in domestic animal production. However, it is unclear whether OLA has negative effects on mammalian oocyte quality and fetal development. In this study, toxic effects of OLA were tested by intragastric gavage ICR mice with water, low-dose OLA (5mg/kg/day), or high-dose OLA (60mg/kg/day) for continuous 45 days. Results showed that high-dose OLA gavage severely affected the offspring birth and growth. Significantly, high-dose OLA impaired oocyte maturation and early embryo development, indicated by the decreased percentage of germinal vesicle breakdown, first polar body extrusion and blastocyst formation. Meanwhile, oxidative stress levels were increased in oocytes or ovaries, indexed by the increased levels of ROS, MDA, H2O2, NO, and decreased levels of GSH, SOD, CAT, GSH-Px and GSH-Rd. Furthermore, aberrant mitochondria distribution, defective spindle assembly, abnormal H3K4me2/H3K9me3 levels, increased DNA double-strand breaks and early apoptosis rate, were observed after high-dose OLA gavage. Taken together, our results for the first time illustrated that high-dose OLA gavage led to sub-fertility of females, which means that restricted utilization of OLA as feed additive should be considered.

Generation of Transgenic Cloned Buffalo Embryos Harboring the EGFP Gene in the Y Chromosome Using CRISPR/Cas9-Mediated Targeted Integration.

Sex control technology is of great significance in the production of domestic animals, especially for rapidly breeding water buffalo (bubalus bubalis), which served as a research model in the present study. We have confirmed that a fluorescence protein integrated into the Y chromosome is fit for sexing pre-implantation embryos in the mouse. Firstly, we optimized the efficiency of targeted integration of exogenous gene encoding enhanced green fluorescent protein (eGFP) and mCherry in Neuro-2a cells, mouse embryonic stem cells, mouse embryonic cells (NIH3T3), buffalo fetal fibroblast (BFF) cells. The results showed that a homology arm length of 800 bp on both sides of the target is more efficient that 300 bp or 300 bp/800 bp. Homology-directed repair (HDR)-mediated knock-in in BFF cells was also significantly improved when cells were supplemented with pifithrin-μ, which is a small molecule that inhibits the binding of p53 to mitochondria. Three pulses at 250 V resulted in the most efficient electroporation in BFF cells and 1.5 μg/mL puromycin was found to be the optimal concentration for screening. Moreover, Y-Chr-eGFP transgenic BFF cells and cloned buffalo embryos were successfully generated using CRISPR/Cas9-mediated gene editing combined with the somatic cell nuclear transfer (SCNT) technique. At passage numbers 6–8, the growth rate and cell proliferation rate were significantly lower in Y-Chr-eGFP transgenic than in non-transgenic BFF cells; the expression levels of the methylation-related genes DNMT1 and DNMT3a were similar; however, the expression levels of the acetylation-related genes HDAC1, HDAC2, and HDAC3 were significantly higher (p < 0.05) in Y-Chr-eGFP transgenic BFF cells compared with non-transgenic cells. Y-Chr-eGFP transgenic BFFs were used as donors for SCNT, the results showed that eGFP reporter is suitable for the visualization of the sex of embryos. The blastocyst rates of cloned buffalo embryos were similar; however, the cleavage rates of transgenic cloned embryos were significantly lower compared with control. In summary, we optimized the protocol for generating transgenic BFF cells and successfully generated Y-Chr-eGFP transgenic embryos using these cells as donors.

Isotopic dietary patterns of monks: results from stable isotope analyses of a seventeenth–eighteenth century Basilian monastic community in Vilnius, Lithuania

The aim of the research focuses on reconstructing diet of the seventeenth–eighteenth century Basilian monks who were buried in the crypt beneath the Holy Trinity Uniate Church in Vilnius, Lithuania. For this aim, stable carbon (δ13C) and nitrogen (δ15N) isotope analyses of human bone collagen samples (n = 74, of which 39 yielded reliable isotopic data) were performed. In order to establish the isotopic dietary baseline for the Basilian monks, we sampled faunal bones (n = 47, of which 34 yielded reliable isotopic data) recovered during archaeological investigations in the area around the Vilnius Lower Castle and the Palace of the Grand Dukes of Lithuania. Faunal samples were comprised of various domestic and wild terrestrial animals, freshwater and anadromous fish, and migratory and non-migratory birds. In total, 121 human and faunal samples were analysed. The isotopic data collected in our study suggest that C3 plant and domestic animal products were the main components in the diets of the Basilian monks, while freshwater fish played a noticeable, yet a much smaller dietary role. However, historical sources describe a reverse dietary picture, i.e. a higher dietary contribution from fish and a lower from animal products. The potential reasons for this incongruity between isotopic and historical dietary evidence were also explored. Finally, the isotopic data of the Basilian monks were compared with that of contemporary Lithuanian nobles and commoners. The comparisons indicate that monastic dietary patterns were more similar to those of the nobility than those of the commoners.

Recent advances in the effects and mechanism of selenium on the quality of domestic animal products

Selenium is an essential trace element for the body. Selenium plays important roles in the enhancement of antioxidant capability, regulation of immune response, promotion of growth and development, and is involved in nutrition metabolism and reproduction as well. Selenium has been used as an antioxidant additive in animal feed for decades and its application is widely increasing in recent years. Dietary supplementation with selenium not only improves carcass traits and meat quality of livestock, but also increases the accumulation of selenium in meat, eggs and milk, which help improve daily uptake of selenium for humans. This review summarizes the recent advances in the effects of supplementation of selenium with different sources, levels and periods on the quality of domestic animal products. Furthermore, the mechanisms of the improvement of animal products by selenium are also discussed.

Effects of Wilting and Dew on the Water Isotope Composition of Detached Grass in Temperate Grassland.

Understanding the water isotopes in feed products derived from grass is fundamental for tracing domestic animal products. Grass silage water was reported to have fewer heavy isotopes than fresh grass, but it is still unknown whether dew formation (either dewfall or dewrise), exchange with soil water, or other processes override the expected enrichment of heavy isotopes due to wilting. The isotopic variations of water (δ2H, δ18O) in fresh grass and cut grass during wilting on soil and on plastic were compared in this study. Drying enriched heavier isotopes, but this was overridden by three processes that finally caused low δ2H and δ18O values: (i) the adsorption of humidity from the surroundings, (ii) the exchange with humidity, and (iii) the depletion of heavy water isotopes close to organic surfaces, called the surface effect, which was the most dominant effect at the end of drying when the water content became low.

Selection signatures of litter size in Dazu black goats based on a whole genome sequencing mixed pools strategy

Litter size is considered to be the most important index for estimating domestic animal productivity. Due to its complexity, the molecular mechanism of litter size has not been elucidated, and it has restricted the use of marker-assisted selection to create high-yield populations in goats. A genome-wide selective sweep analysis was performed with 31 Dazu black goats to identify significant genomic regions and candidate genes related to litter size by a mixed pools strategy. A total of 96 candidate genes were identified, including NR6A1, STK3, IGF2BP2, AR, HMGA2, NPTX1, ANKRD17, DPYD, CLRB, PPP3CA, PLCB1, STK3 and HMGA2, using mixed pool analysis with ZHp and FST. We classified these candidate genes based on the functional classification and annotation of signaling pathways. According to the GO and KEGG analysis results, a total of 43 GO terms and 108 pathways were annotated from these genes. In particular, some novel candidate genes were enriched in reproduction-related pathways, such as the estrogen signaling pathway and oocyte meiosis. These findings provide insight into the influences of coding genes on the fecundity traits of goats.

Molecular characterization of highly pathogenic Eimeria species among beef cattle on Java Island, Indonesia

Gastrointestinal parasites including Eimeria spp. are known to affect domestic animal productivity causing watery or lethal bloody diarrhea. However, there are few reports on the detailed distribution of bovine Eimeria spp. in cattle, particularly in developing tropical and sub-tropical areas. Using a total of 289 fecal samples collected from beef cattle on Java Island, one of the five main islands of Indonesia, fecal examinations by the Whitlock and sugar flotation methods and molecular surveys were conducted to reveal the prevalence of 6 Eimeria spp. As a result of morphological screening using Whitlock methods and sugar flotation, Eimeria spp. prevalences of 9.4% and 52.3% were confirmed, respectively. The prevalence was higher in younger cattle [under 1 year (63.9%), 1–2 years (75.0%) and more than in 2 year old cattle (42.3%)]. The prevalences of identified species were as follows: 10.4% for E. bovis, 2.8% for E. ellipsoidalis, 2.1% for E. alabamensis, 1.4% for E. zuernii, 1.1% for E. auburnensis, and 0.4% for E. cylindrica. Moreover, prevalences of 12.8% for Strongyloides papillosus, 7.3% for Trichuris globulosa, and 0.3% for Capillaria bovis were detected. Although the average number of oocysts per gram of feces was <100 among the positive samples, and cases of heavy infection were limited, the endemicity of these pathogenic Eimeria species among farms in Indonesia should be noted.

201 Testing of single guide RNAs, optimization of transfection, and selection systems for the generation of SRY knockout foetal fibroblast cells

Obtaining male and female cells from a male could have important implications for endangered mammalian species and domestic animal production. Achieving this could constitute a proof of concept of the use of assisted reproduction technologies for the conservation of endangered species. In particular, SRY is the principal male sex determinant gene and is found on the short arm of the Y chromosome. With the introduction of nuclease-mediated genome editing technologies, such as the CRISPR/Cas9 system, it is possible to envision precise DNA targeting in this gene as strategy to manipulate the sex of cell lines. Based on the above, we tested the CRISPR/Cas9 system to later create knockout (KO) cell lines of the SRY gene in bovine. The aim of this work was (1) to test the efficiency of single guide (sg)RNAs designed to target the bovine SRY gene in HEK293T cell line, and (2) to optimize blasticidin concentrations and electroporation conditions in bovine fetal fibroblast (BFF). To test sgRNA efficiency, we used 3 sgRNA designed and tested over the sequence of bovine SRY gene (690bp). The efficiency of each sgRNA was evaluated in a heterologous way by using a modification of pCAG-EGxxFP (plasmid #50716, Addgene, Cambridge, MA, USA) in which we inserted the bovine SRY sequence (NCBI Reference Sequence: NC_016145.1), and that only results in green fluorescent protein (GFP) expression upon cutting by the CRISPR/Cas9 system. We transfected the HEK293T cell line with the following groups to assess the efficiency of 3 sgRNA: (1) btSRY1+Cas9+pCAG-EGSRYFP; (2) btSRY2+Cas9+pCAG-EGSRYFP; (3) btSRY3+Cas9+pCAG-EGSRYFP; (4) PU6-empty+Cas9+pCAG- EGSRYFP; (5) GFP-only control. In addition, 6 blasticidin concentrations (0, 1, 2.5, 5, 10, and 20µg mL−1) and 3 electroporation conditions (Tfx1, Tfx2, and Tfx3) were tested, both in BFF. Electroporation conditions were as follows: Tfx1=1.25 kV cm−1; number of pulses=3; electrode gap=4 mm; interval=100 ms; Tfx2=1.2 kV/cm; number of pulses=4; electrode gap=4 mm; interval=100 ms; and Tfx3=voltage: 350V, LV mode; pulse length=100 µs; number of pulses=4; electrode gap=4 mm; interval=100ms. Statistical analyses were performed using 2-tailed Mann-Whitney tests. Results for sgRNA efficiency, based on GFP expression by counting GFP+ cells under fluorescent microscopy showed that btSRY1 (17%) and btSRY2 (13%) worked significantly better than btSRY3 (1%). The blasticidin selection assay showed that 5, 10, and 20µg mL−1were significantly more lethal than 0, 1 and 2.5µg mL−1, by counting living cells in Neubauer chamber. We chose 5µg mL−1 as the concentration for future experiments. Last, the Tfx2 electroporation protocol (11.34%) was more efficient than the other 2 protocols tested (Tfx1 and Tfx3: 3.48 and 0.86%, respectively), based on the counting of GFP+ cells under fluorescent microscopy. Electroporation of BFF with btSRY1, btSRY2, or both and Cas9 using Tfx2 protocol and molecular characterisation of colonies are currently in progress with the ultimate objective of producing SRY knockout bovine embryos by somatic cell nuclear transfer.

Application of some trees/shrubs in ruminant feeding: a review

Ruminants play an important role in supplying human nutritional requirements. Given the increasing number of livestock and the limited resources to supply feedstuffs in order to feed ruminants, scientists are seeking ways to add to the ruminants’ diets parts of trees and shrubs and to replace concentrates competitive with human food. A consequent positive result could be reduction of the costs for meat and milk yield. On the other hand, these feeds could contain some anti-nutritional factors such as tannins that can limit their use. In this paper, the use of components of some trees and shrubs as part of ruminant (cattle, sheep and goat) diets as well as their positive and negative effects on domestic animal productivity are reviewed.

Heat stress: physiology of acclimation and adaptation.

Climate is the most important ecological factor determining the growth, development, and productivity of domestic animals (Adams et al., 1998). Climate changes impact the economic viability of livestock production systems worldwide (Klinedinst et al., 1993) through a variety of routes. These include changes in food availability and quality, changes in pest and pathogen populations, alteration in immunity and both direct and indirect impacts on animal performance, such as growth, reproduction, and lactation. Lack of prior conditioning (acclimatization) to sudden change in weather often results in catastrophic losses in the domestic livestock industry (Thornton et al., 2009) Despite uncertainties in climate variability, the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report identified the “likely range” of increase in global average surface temperature between 0.3 °C and 4.8 °C by the year 2100 (IPCC, 2014). The risk potential associated with livestock production systems due to global warming can be characterized by levels of vulnerability, as influenced by animal performance and environmental parameters (Hahn, 1995). As production levels (e.g., rate of gain, milk production per day, eggs per day) increase, the sensitivity and tolerance to stress increases and, when coupled with an adverse environment, the animal is at greater risk. Nationally, heat stress results in total economic losses ranging between $1.9 and $2.7 billion per year (St-Pierre et al., 2003). Although projected increases in ambient temperatures will result in additional financial losses, the extra metabolic heat resulting from the projected increase in animal productivity will have far greater impact, which has been estimated at between two and four times as much as global warming (St-Pierre et al., 2003; St.-Pierre, 2013). Our understanding of the mechanisms by which environmental stress reduces productivity of domestic animals has greatly improved over the last century (Collier et al., 2017). However, it has been difficult to genetically alter production animals to improve their tolerance to thermal stressors. For example, decades of research using genetically defined populations demonstrated that using conventional crossbreeding approaches to improve resistance to thermal stress in the dairy industry always resulted in lower milk yields in the F1 generation, the same holds true for live weight gain in meat animals (Branton et al., 1974; Frisch and Vercoe, 1977). Therefore, improving productivity in animals exposed to adverse environmental conditions during the last quarter century focused on modifying the environment and improving nutritional management while applying selection pressure on improving yields rather than improving stress resistance. This approach dramatically increased productivity of domestic animals but also increased their sensitivity (reduced their thermal plasticity) to high temperatures in general because of their greater internal heat load. The purpose of this review is to define processes by which domestic animals respond to changes in their environment. These processes are critical to survival but often negatively impact productivity and profitability of livestock operations. However, understanding how these processes are controlled offer opportunities for improving thermal stress resistance.

Species-specific expression of phosphoglycerate kinase 2 (PGK2) in the developing porcine testis

Whereas stage-specific markers for spermatogonial cells have been well investigated in mouse, the specific markers of germ cells in the testis of domestic animals have not been well defined. Phosphoglycerate kinase (PGK), an enzyme that converts 1,3-bisphosphoglycerate and adenosine diphosphate to 3-phosphoglycerate and adenosine triphosphate, has two isozymes: PGK1 and PGK2. In mouse, PGK1 exists only during the early stages of spermatogenesis, and PGK2 is then expressed during the pachytene spermatocyte stage. In this study, we investigated the localization of PGK2 in the developing porcine testis, and compared the similarities and differences in its expression with that of the PGK2 in mouse. The PGK2 protein was found to be exclusively expressed in spermatids of the adult mouse testis, whereas PGK2-positive cells were observed in the prepubertal and postpubertal testes of pigs. Based on this result, we examined the expression of PGK2 in in vitro-cultured porcine undifferentiated spermatogonia and found it to be maintained in the cultured cells. To verify this result and identify the spermatogonial stem cell-like potential in recipient testes, PKH26 dye-stained PGK2-positive cells were transplanted into the testes of busulfan-treated immunodeficient mouse that had been depleted of both testicular germ cells and somatic cells. The transplanted cells colonized the recipient testis at 8 weeks post transplantation, and fluorescence microscopy identified the cells in the basement membranes of the seminiferous tubules of the injected mouse. Taken together, our results suggest that PGK2 is expressed differently in the testes of mouse and pigs according to developmental stage. This finding should contribute to the study of spermatogenesis and the production of transgenic domestic animals through in vitro spermatogonial sperm cell culture.

Desde los primeros puestos rurales hasta la estancia moderna del sur bonaerense: un recorrido arqueológico

El avance de la población criolla sobre territorio indígena en el sur bonaerense desde la segunda mitad del siglo XIX implicó la emergencia, conformación y consolidación de un nuevo ámbito, el rural. En este trabajo, se discuten a nivel regional y comparativo los resultados del estudio arqueológico de los puestos rurales Las Toscas 3 y Máximo Ortiz y la estancia La Libertad. Dicha discusión se centró en el uso del espacio en las instalaciones rurales referidas, la producción y explotación de animales domésticos, la dieta rural, los hábitos de consumo relacionados con una gran cantidad de artículos y bienes europeos, entre otros aspectos.

Domestic animal production and consumption at Tall al-Handaquq South (Jordan) in the Early Bronze III

The Early Bronze Age (EBA) in the Southern Levant saw the emergence of socioeconomic inequality, fortified towns, and craft specialization. Livestock production was key to facilitating these socioeconomic changes, but the precise forms of animal husbandry and the economic contributions of domestic animal herding to EBA economies in the Southern Levant remain underexplored. Here, we investigate faunal remains recovered from Tall al-Handaquq South (THS), a walled Early Bronze III settlement located in the northern Jordan Valley. Zooarchaeological analyses indicate that small-stock (sheep and goat) herding formed the basis of subsistence and surplus production, while cattle husbandry provided much needed labour for intensive cereal production. The high relative abundance of cattle and the preference for goats, which thrive on low quality forage typical for more marginal landscapes beyond the valley floor, over sheep may indicate use of a more extensive herding strategy that kept herds off of agricultural fields while maintaining animal production. Notably, caprine management systems shifted throughout the EB III at THS from strategies emphasizing the optimal production of meat obtained from prime-aged sheep and goats to one focused on the exploitation of older animals, perhaps for fiber production. During this time, however, goats continued to outnumber sheep, possibly reflecting the longterm importance of grain production, which is expected to be reflected in the faunal record by high proportions of goats and cattle. Comparing the data from THS to other sites in the Southern Levant, the data indicate an evolution towards a greater focus on agricultural and livestock commodity production, factors that may have contributed to the abandonment of THS and, perhaps, other walled sites in the region.

A conceptual model to describe heat stress in dairy cows from actual to questionable loops

Se reconoce que el ambiente térmico es uno de los factores ecológicos más importantes para determinar el crecimiento, el desarrollo y la productividad de animales domésticos con efectos directos e indirectos sobre su fisiología y comportamiento. A pesar de tener una adaptación específica e individual, es muy común que, dentro de las variaciones de temperatura estacionales o diurnas, los animales se enfrenten a situaciones fuera de su zona de confort térmico. Debido al estrés calórico, las vacas lecheras reducen su producción y fertilidad, y por lo tanto, llevan a cabo un aumento en la incidencia de trastornos metabólicos, causando bajos causando bajos ingresos para la finca en corto y mediano plazo. El cambio climático es quizás uno de los factores más importantes en las respuestas de los animales. Este estudio tuvo como objetivo describir y comprender las interacciones de las variables asociadas con el estrés por calor en el ganado lechero. El enfoque del sistema aplicado a este mecanismo fisiológico específico ayuda aliviar el estrés calórico en vacas lecheras cuando se relacionan los aspectos de pastoreo y las necesidades del animal. Se usó una anotación de diagrama de bucle causal para conectar las variables biológicas incluidas en los límites del sistema. Las conexiones causales se validaron con algunas citas bibliográficas sobre la influencia del estrés calórico. Las interconexiones de retroalimentación más importantes resaltadas, subrayan la estructura dominante y los patrones esperados. Se encontraron cuatro bucles balance implicados en los mecanismos fisiológicos utilizados por los animales para reducir la producción de calor metabólico y para regular la homeostasis de la temperatura interna.

Global patterns and determinants of the economic importance of bushmeat

Knowledge about the economic role of bushmeat in rural livelihoods mainly stems from small case studies in sites characterised by high hunting intensities, challenging the formation of national-level conservation and development policies. We use the global Poverty Environment Network data to analyse the economic importance of bushmeat to rural households in sites selected with no consideration of the level of bushmeat hunting. Data were gathered from 7978 households in 333 communities across 24 tropical and sub-tropical countries in Latin America, Asia, and Sub-Saharan Africa. We report prevalence of hunting; absolute bushmeat income (both cash and subsistence income); share of bushmeat income in total household income; and share of bushmeat income obtained in cash. We investigate patterns and determinants of these variables at the community mean level using generalized linear models, focusing on six general hypothesis identified from the literature. Hunting is more prevalent than generally assumed (39%) but contributes less to rural household income than expected (2%) and mainly through own consumption (87%). Bushmeat is more important in smaller and more remote communities, in communities in the middle of the cash income distribution, communities with few domestic animals, in countries characterised by poor governance, and with rising costs of living. We argue that bushmeat is likely to be most important to rural households as a source of protein and micronutrients unavailable through own domestic animal and staple crop production. Wildlife conservation therefore would benefit from policies simultaneously addressing household-level food and nutritional security.

The clinical features of 590 patients with brucellosis in Xinjiang, China with the emphasis on the treatment of complications.

BackgroundThis study aims to analyze the clinical characteristics and treatment outcomes of 590 patients with brucellosis in Xinjiang, China.Methodology and principal findingsThe clinical characteristics, laboratory findings, complications and prognosis of 590 patients infected with brucellosis were retrospectively analyzed. These patients had a mean age of 44.24 ± 15.83 years with 60.5% having a history of close contacting with cattle and sheep. Of them, 53.6% (316 /590) were in acute phase and 21.5% were in chronic phase. Agglutination test showed 98.5% positive with 34% blood culture positive of Brucella. The major symptoms were fatigue (91%), hyperhidrosis(88.1%), fever(86.9%), and joint pain(81%) with 29.8% having enlarged liver, 26.1% having enlarged spleen and 23.2% having osteoarticular complications. Combination of doxycycline plus rifampicin for 12 weeks was an effective regimen for patients without complications. The 3-drug regimen (doxycycline+rifampicin+levofloxacin) for 12 weeks was recommended for these with complications. There were 6 patients died (1.02%) with overall relapse rate of 5.98%.ConclusionsBrucellosis is mostly associated with contacting with domestic animal production in Xinjiang, China. Clinical symptoms include fever, fatigue, hyperhidrosis, and joint pain with common complication of osteoarticular involvement. Three-drug-regimen of doxycycline+rifampicin+levofloxacin for 12 weeks was effective for these patients with complications.

GIS-based approach applied to optimizing recommendations of Eucalyptus genotypes

The study of the genotype×environment interaction is a prominent issue, requiring care for recommending improved superior genotypes to certain areas. Experimentally, it is possible to infer that the puzzle of genotype recommendations relies on edaphic and climatic changes over different terrain latitudes and longitudes, and further fluctuates in microenvironments as a result of site variations. Different gene expression is activated or suppressed in accordance with environmental requirements, resulting in phenotypic plasticity of cultivars. The goal of this study was to generate an optimal recommendation of eucalyptus genotypes in a 6846.0km2 using climatic and geographical information. For this purpose, we used 24 clones unevenly distributed in 988 plots over the area, with planting ages between 2.5 and 6.5years. The evaluated trait was production, measured in cubic meters of wood per hectare. Our study area typically has a mid-to-low altitude range (0–390m), rainfall between 599 and 1749mm, temperature from 22 to 25°C, and a series of other bioclimatic variables. For statistical analysis, we used the random regression via mixed-effects models (REML/BLUP) combined with logistic growth models. Among the total number of clones, six proved to be the most suitable to maximize volumetric production in the work area. In addition, a change in the recommendation was verified for clones between 2.5 and 6.5years of age. This study presents an alternate concept of environmental stratification, which to date has been made categorically by evaluating a number of locations. Our study proposes a way to perform quantitative stratum over an entire area, according to the environmental gradient. The optimal selection of genotypes promotes increased wood production without necessarily increasing the planting area, which is extremely desirable because land is a resource that is becoming increasingly scarce. Furthermore, eucalyptus productivity represents an important part of the costs and revenues of the forest enterprise, such that minimal improvements can significantly affect profit margins. The proposed method is easily adapted for use for other crops and domestic animal production.

Molecular characterization and antibiotic resistance profiles of Salmonella isolated from fecal matter of domestic animals and animal products in Nairobi

BackgroundSalmonella has significant public health implications causing food borne and zoonotic diseases in humans. Treatment of infections due to Salmonella is becoming difficult due to emergence of drug resistant strains. There is therefore need to characterize the circulating non-typhoidal Salmonella (NTS) serovars in domestic animals and animal products in Kenya as well as determine their antibiotic resistance profiles.MethodsA total of 740 fecal samples were collected from cows (n = 150), pigs (n = 182), chicken (n = 191) and chicken eggs (n = 217) from various markets and abattoirs in Nairobi. The prevalence of NTS serovars using culture techniques and biochemical tests, antimicrobial sensitivity testing using disc diffusion method of the commonly prescribed antibiotics and phylogenetic relationships using 16S rRNA were determined.ResultsThe results showed that the overall prevalence of Salmonella was 3.8, 3.6, 5.9 and 2.6% for pigs, chicken, eggs and cows respectively. Two serovars were isolated S. Typhimurium (85%) and S. Enteritidis (15%) and these two serovars formed distinct clades on the phylogenetic tree. Forty percent of the isolates were resistant to one or more antibiotics.ConclusionThe isolation of Salmonella Typhimurium and Salmonella Enteritidis that are resistant to commonly used antibiotics from seemingly healthy animals and animal products poses a significant public health threat. This points to the need for regular surveillance to be carried out and the chain of transmission should be viewed to ascertain sources of contamination.

Risk-based approach to developing a national residue sampling plan for testing under European Union regulation for veterinary medicinal products and coccidiostat feed additives in domestic animal production

ABSTRACTA ranking system for veterinary medicinal products and coccidiostat feed additives has been developed as a tool to be applied in a risk-based approach to the residue testing programme for foods of animal origin in the Irish National Residue Control Plan (NRCP). Three characteristics of substances that may occur as residues in food are included in the developed risk ranking system: Potency, as measured by the acceptable daily intake assigned by the European Medicines Agency Committee for Medicinal Products for Veterinary Use, to each substance; Usage, as measured by the three factors of Number of Doses, use on Individual animals or for Group treatment, and Withdrawal Period; and Residue Occurrence, as measured by the number of Non-Compliant Samples in the NRCP. For both Number of Doses and Non-Compliant Samples, data for the 5-year period 2008–12 have been used. The risk ranking system for substances was developed for beef cattle, sheep and goats, pigs, chickens and dairy cattle using a scoring system applied to the various parameters described above to give an overall score based on the following equation: Potency × Usage (Number of Doses + Individual/Group Use + Withdrawal Period) × Residue Occurrence. Applying this risk ranking system, the following substances are ranked very highly: antimicrobials such as amoxicillin (for all species except pigs), marbofloxacillin (for beef cattle), oxytetracycline (for all species except chickens), sulfadiazine with trimethoprim (for pigs and chickens) and tilmicosin (for chickens); antiparasitic drugs, such as the benzimidazoles triclabendazole (for beef and dairy cattle), fenbendazole/oxfendazole (for sheep/goats and dairy cattle) and albendazole (for dairy cattle), the avermectin ivermectin (for beef cattle), and anti-fluke drugs closantel and rafoxanide (for sheep/goats); the anticoccidials monensin, narasin, nicarbazin and toltrazuril (for chickens). The risk ranking system described is a relatively simple system designed to provide a reliable basis for selecting the veterinary medicinal products and coccidiostat feed additives that might be prioritised for residue testing.

Hyperendemic Campylobacter jejuni in guinea pigs (Cavia porcellus) raised for food in a semi-rural community of Quito, Ecuador.

Domestic animals and animal products are the source of pathogenic Campylobacter jejuni and C. coli in industrialized countries, yet little is known about the transmission of these bacteria in developing countries. Guinea pigs (Cavia porcellus) are commonly raised for food in the Andean region of South America, however, limited research has characterized this rodent as a reservoir of zoonotic enteric pathogens. In this study, we examined the prevalence of Campylobacter spp. in 203 fecal samples from domestic animals of 59 households in a semi-rural parish of Quito, Ecuador. Of the twelve animal species studied, guinea pigs showed the highest prevalence of C. jejuni (n = 39/40; 97.5%). Multilocus sequence typing (MLST) was used to characterize the genetic relationship of C. jejuni from domestic animals and 21 sequence types (STs) were identified. The majority of STs from guinea pigs appeared to form new clonal complexes that were not related to STs of C. jejuni isolated from other animal species and shared only a few alleles with other C. jejuni previously characterized. The study identifies guinea pigs as a major reservoir of C. jejuni and suggests that some C. jejuni strains are adapted to this animal species.