Physiological effects of arginine vasotocin and mesotocin in cockerels

1. The effects of continuous infusion of 0.1, 1.0 and 10.0 mU/min/kg body weight of arginine vasotocin (AVT) or mesotocin (MT) on cardiovascular and thermoregulatory responses, on plasma osmolality and ionic composition and on plasma concentrations of AVT, MT, prolactin and aldosterone, were investigated in conscious White Leghorn cockerels.

2. Neither of the peptides, at any dose, affected cardiovascular functions, plasma ions and osmolality. Infusion of MT at the rate of 10 mU/min/kg body weight increased respiratory rate. Both peptides at doses of 1 and 10 mU/min/kg reduced the temperatures of the comb and shank but had no effect on the skin and cloaca.

3. Doses of 0.1 and 1.0 mU MT/mu/kg reduced plasma aldosterone and at 10 mU/min/kg increased plasma AVT. At any given dose MT had no effect on plasma prolactin. AVT at 0.1 and 1.0 mU/min/kg of AVT reduced plasma MT. AVT at 1.0 mU/min/kg increased plasma prolactin and at 10 mU/min/kg reduced plasma aldosterone.

4. During saline infusion, plasma MT was positively correlated with plasma AVT and negatively correlated with respiratory rate and cloacal temperature. Plasma AVT showed a positive correlation with plasma MT and aldosterone and a negative correlation with respiratory rate and skin temperature.

5. During saline infusion, there was no significant correlation between cardiovascular functions, or plasma osmolality and ionic composition and plasma MT or AVT.

6. The present study suggests that interrelationships between circulating concentrations of AVT and MT do exist and that AVT affects     

A 3-year assessment of nitrous oxide emission factors for urine and dung of grazing sheep in a subtropical ecosystem

Purpose

Grazing livestock has strong impact on global nitrous oxide (N₂O) emissions by providing N sources through excreta. The scarcity of information on factors influencing N₂O emissions from sheep excreta in subtropical ecosystems such as those of Southern Brazil led us to conduct field trials in three different winter pasture seasons on an integrated crop–livestock system (ICL) in order to assess N₂O emission factors (EF-N₂O) in response to variable rates of urine and dung.

Materials and methods

The equivalent urine-N loading rates for the three winter seasons (2009, 2010, and 2013) ranged from 96 to 478 kg ha^?1, and the dung-N rates applied in 2009 and 2010 were 81 and 76 kg ha^?1, respectively. Air was sampled from closed static chambers (0.20 m in diameter) for approximately 40 days after excreta application and analyzed for N₂O by gas chromatography.

Results and discussion

Soil N₂O-N fluxes spanned the ranges 4 to 353 μg m^?2 h^?1 in 2009, ??47 to 976 μg m^?2 h^?1 in 2010, and 46 to 339 μg m^?2 h^?1 in 2013. Urine addition resulted in N₂O-N peaks within for up to 20–30 days after application in the 3 years, and the strength of the peaks was linearly related to the N rate used. Emission factors of N₂O (EF-N₂O, % of N applied that is emitted as N₂O) of urine ranged from 0.06 to 0.34% and were essentially independent of N rate applied. By considering a ratio of N excreted by urine and dung of 60:40, a single combined excretal EF-N₂O of 0.14% was estimated.

Conclusions

Our findings showed higher mean EF-N₂O for sheep urine than that for dung (0.21% vs 0.03%), irrespective of the occurrence or not of urine patches overlap. This value is much lower than default value of 1% of IPCC’s Tier 1 and reinforces the needs of its revision.

     

Phage sensitivity in relation to pathogenicity and virulence of the cotton bacterial blight pathogen of Sudan

At least two pathotypes of Xanthomonas campestris pv. malvacearum are now known to exist in Sudan. The pre-Barakat (race 1) and post-Barakat (race 2) pathogens have been shown to exhibit different host specificity. The former is pathogenic and highly aggressive on only cultivars with no resistance genes or with the B₂ and/or B₃ resistance factors, while the latter can infect the B₆ cultivars also. Race 2 in Sudan, which was previously reported to infect all the standard differentials, produced milder angular leaf spot symptoms and occasionally restricted vein infection. Moreover, it exhibited reduced growth in planta compared with race 1.
Bacteriophage studies revealed that the two races are quite distinct in their phage sensitivity. Race 1 can be lysed by only three, or rarely four, of the six phages used for typing, while race 2 is sensitive to all of them. The present study suggests that phage 7 may be the type-determining phage for race 2. Race 2 strain mutants resistant to phage 3 or 4 were found to be sensitive to phage 7 and pathogenic to both Acala and Barakat, although showing marked attenuation of virulence. However, mutants resistant to phage 2 or 7 were insensitive to all the phages and although they retained their pathogenicity to Acala, they either lost the ability to infect Barakat or produced a hypersensitive reaction. The resistance of all mutants was found to be due to failure to adsorb the homologous phage, indicating a change in the cell wall. The association of this with the attenuation of virulence suggests that bacterial wall components may function as virulence determinants in Xanthomonas campestris pv. malvacearum.     

Effect of a single injection of gonadotropin-releasing hormone (GnRH) and human chorionic gonadotropin (hCG) on testicular blood flow measured by color doppler ultrasonography in male Shiba goats

Although color Doppler ultrasonography has been used to evaluate testicular blood flow in many species, very little has been done in goat. Eight male Shiba goats were exposed to a single intramuscular injection of either gonadotropin-releasing hormone (GnRH group; 1 µg/kg BW) or human chorionic gonadotropin (hCG group; 25 IU/kg BW). Plasma testosterone (T), estradiol (E2) and inhibin (INH) were measured just before (0 hr) and at different intervals post injection by radioimmunoassay. Testis volume (TV) and Doppler indices, such as resistive index (RI) and pulsatility index (PI) of the supratesticular artery, were measured by B-mode and color Doppler ultrasonography, respectively. The results indicated an increase in testicular blood flow in both groups, as RI and PI decreased significantly (P<0.05), but this increase was significant higher and earlier in hCG group (1 hr) than in the GnRH group (2 hr). A high correlation was found for RI and PI with both T (RI, r= −0.862; PI, r= −0.707) and INH in the GnRH group (RI, r=0.661; PI, r=0.701). However, a significant (P<0.05) correlation was found between E2 and both RI (r= −0.610) and PI (r= −0.763) in hCG group. In addition, TV significantly increased and was highly correlated with RI in both groups (GnRH, r= −0.718; hCG, r= −0.779). In conclusion, hCG and GnRH may improve testicular blood flow and TV in Shiba goats.     

Method of determination of nitrosamines in sausages by CO2 supercritical fluid extraction (SFE) and micellar electrokinetic chromatography (MEKC)

In this paper, the use of supercritical fluid extraction (SFE) and micellar electrokinetic capillary chromatography (MEKC) is proposed for the complete analysis of volatile nitrosamines in sausages. The extraction fluid used was CO2 and variables such as density, temperature of thimbles, extraction time, modifier, fluid flow, and kind of traps were investigated. Several experiments were carried out to obtain the most favorable conditions for analysis of volatile nitrosamines in sausages. The recoveries ranged from 21 to 82% for the five nitrosamines studied. The optimal condition of extraction was 0.2 g of sample fortified with 10 mg/kg, using dynamic extraction during 20 min and with adsorbent Florisil in the trap. The solvent selected for the elution of the analytes was methanol.     

Drivers and risk factors for circulating African swine fever virus in Uganda, 2012–2013

We explored observed risk factors and drivers of infection possibly associated with African swine fever (ASF) epidemiology in Uganda. Representative sub-populations of pig farms and statistics were used in a case-control model. Indiscriminate disposal of pig viscera and waste materials after slaughter, including on open refuse dumps, farm-gate buyers collecting pigs and pig products from within a farm, and retention of survivor pigs were plausible risk factors. Wire mesh-protected windows in pig houses were found to be protective against ASF infection. Sighting engorged ticks on pigs, the presence of a lock for each pig pen and/or a gate at the farm entrance were significantly associated with infection/non-infection; possible explanations were offered. Strict adherence to planned within-farm and community-based biosecurity, and avoidance of identified risk factors is recommended to reduce infection. Training for small-scale and emerging farmers should involve multidimensional and multidisciplinary approaches to reduce human-related risky behaviours driving infection.     

Self-Assembled Smectic Phases in Rod-Coil Block Copolymers

Rod-coil block copolymers are self-assembling polymers that combine the physics of orientational ordering of rodlike polymers and the microphase separation of coil-coil block copolymers. Several new solid-state morphologies were observed in a series of anionically synthesized model poly(hexyl isocyanate-b-styrene) rod-coil diblock copolymers examined by transmission electron microscopy and selected-area electron diffraction. The rod-coils formed smectic C-like and O-like morphologies with domain sizes ranging from tens of nanometers to almost 1 micrometer. Both structural and orientational changes were found for increasing rod volume fractions. In addition, some morphologies exhibited spontaneous long-range orientational order over many tens of micrometers.     

Cuticular hydrocarbons in two parapatric species of ants and their hybrid

Discrimination between nestmates and non‐nestmates in social insects is thought to rely on the pattern of cuticular hydrocarbons. We investigated the cuticular hydrocarbon profiles of 2 parapatric sibling ant species, Temnothorax nylanderi (Förster, 1850) and Temnothorax crassispinus (Karavaiev, 1926), and their hybrid. We found that although the profiles show considerable similarities, a discriminant analysis based on the relative peak areas of cuticular hydrocarbons separates the 3 taxa. The profiles of hybrids were not consistently intermediate between those of the paternal species, suggesting either non‐additive interactions among the parental biosynthetic pathways or systematic differences in environment‐derived odor cues.