Assessment of cold tolerance at early developmental stages and allelic variation at candidate genes in South American rice germplasm

Rice is susceptible to cold during early developmental stages. Most tolerant cultivars have been developed for other conditions than those occurring in South America’s rice growing areas, or their grain type is not suitable for the local markets. If locally adapted varieties were available, growers could anticipate sowing date, making flowering time coincide with the moment of maximum solar radiation and increasing yields. In this work, 116 rice inbred lines and varieties of diverse origin within the South American gene pool were tested for seedling survival and germination percentage under low temperature in controlled conditions. As a result, lines used as controls responded as expected, whereas lines with similar behavior to controls, intermediate between susceptible and tolerant controls and more extreme than controls were detected at both seedling and germination stages. Allelic variation at candidate genes OsGSTZ1, OsGSTZ2 and OsCDPK13 was analyzed in a subset of ten contrasting lines. Ten out of thirty-four polymorphisms detected in all three genes were associated with cold tolerance in these lines. A functional marker, designed from an aminoacid-changing SNP found in gene OsGSTZ2, was tested in the 116 lines. As a result, a tight association was observed between cold tolerance and marker score. In conclusion, wide variability for cold tolerance at early developmental stages has been detected in rice advanced breeding materials that are adapted to local growing conditions. Also, a functional marker tightly associated with the trait is available for performing marker assisted selection.     

A New Approach for Minimizing Ammonia Emissions from Poultry Houses

The paper describes a novel approach to reduce ammonia emissions from Concentrated Animal and Feeding Operations (CAFO) in general, and from poultry houses in particular. The approach is based on installing a dedicated air capturing system on the feeding infrastructure that draws air from close to the litter. Air at these locations has NH_3(g) concentrations an order of magnitude higher than at the vents of the ventilation system. Moreover, while the dedicated waste air drawing system can work continuously, the operation of the ventilation system is intermittent and directed towards maintaining the birds climatically-comfort. The NH_3(g) rich waste air is conveyed to an acidic (0?<?pH?<?~5) bubble column reactor in which ammonia is converted to ${\text{NH}}_4^ + $ . The reactor operates in a batch mode, starting at pH?0 (1?N HCl solution) and is switched to a new acidic absorption solution just before NH_3(g) breakthrough occurs, at around pH 5. Experiments with a wide range of NH_3(g) concentrations showed that the absorption efficiency is practically 100% throughout the process as long as the face velocity is below 4 cm/s. The advantages of the method include high absorption efficiency, lower NH_3(g) concentrations in the vicinity of the birds, generation of a valuable product (a high concentration ammonia solution) and the separation between the ventilation and ammonia treatment systems. A small scale pilot operation conducted for 5 weeks in a broiler house showed the approach to be technically feasible. A larger scale pilot study is required for fine-tuned cost estimation.     

Energy Balance of Callinectes rathbunae Contreras 1930 in Floating Cages in a Tropical Coastal Lagoon

The genus Callinecres is ecologically important in the coastal lagoon region of the Gulf of Mexico. This study was conducted to test the feasibility of raising these crabs in a system of floating cages and to measure their scope for growth in a tropical coastal lagoon of the Gulf of Mexico. The equation P = As - (R + E + N) was used to estimate the scope for growth (P) for C. rathbunae under experimental conditions for 21 days. Ingested food was 3% of body weight. Assimilation (As) was 73% of assimilated energy, 21.4% was channeled to respiration (R), 2% to excretion (N) and 0.16% to exuvia (E). The remainder of the energy was channeled to growth at a net efficiency of 76%. Significant differences were not found between the calculated scope for growth and the growth achieved in the culture system ( P > 0.05). These results support the energy balance equation and suggest that the cultivation of C. rathbunae in floating cages is possible.     

Influence of steam-flaked, steamed-whole or whole shelled corn on performance and digestion in beef steers

Three trials were conducted to evaluate finishing diets containing 67% steam-flaked corn (SFC), steamed-whole corn (SWC) or whole corn (WC). In a feeding trial, steers fed SWC consumed more (P less than .05) dry matter per day (7.6 kg) than those fed WC (7.0 kg) or SFC (6.7 kg). Average daily gain was greater (P less than .05) for steers fed SFC (1.33 kg) and SWC (1.31 kg) than for those fed WC (1.25 kg), and feed efficiency was better (P less than .05) for steers fed SFC (5.06 kg dry matter/kg gain) than for those fed WC (5.62) and SWC (5.79). Carcass characteristics were not different among the three groups. In a digestion trial, method of corn processing did not affect digestibility of dry matter and crude protein. Starch digestibility was greater (P less than .05) for SFC (99.1%) than for SWC (93.8%) and WC (93.0%). There were no differences in nitrogen (N) intake or fecal N among the three diets; however, urinary N was less (P less than .05) for SWC (19 g/d) than for SFC (27 g/d) and WC (32 g/d), and N retention was higher (P less than .05) for the SWC diet. In vitro dry matter digestibility of the SFC diet was higher (P less than .05) than for WC at 4 and 8 h of incubation and higher (P less than .05) than the SWC diet at 8, 12 and 24 h of incubation. In vitro gas production after 6 h was greater (P less than .05) for SFC than for SWC grain, which was greater (P less than .05) than WC.(ABSTRACT TRUNCATED AT 250 WORDS)     

A REVIEW OF IMAGING TECHNIQUES FOR CANINE CAUDA EQUINA SYNDROME

There are many imaging modalities available for evaluating the canine lumbosacral region. These include conventional radiography, stress radiography, myelography, epidurography, transosseous and intravenous venography, discography, linear tomography, computed tomography, and magnetic resonance imaging. Myelography, epidurography and discography are commonly used, but often lack sensitivity. Myelography is of little value when evaluating the cauda equina because the dural sac is elevated from the vertebral canal floor and frequently ends before the lumbosacral junction. Epidurography will identify a ventrally located compressive lesion and discography can delineate the dorsal extent of the diseased disc; however, both are sometimes difficult to interpret. Therefore, more than one of these imaging techniques must be used in order to make a diagnosis. Computed tomography and magnetic resonance imaging have become valuable in evaluating the lumbosacral region in dogs. These modalities have proven to be both sensitive and specific for determining cauda equina compression in both humans and in dogs.     

Bovine babesiosis in dual purpose calves in the state of Yucatan,Mexico

Thirty-eight dual purpose calves in the 3 agricultural zones of the state of Yucatan, Mexico were monitored for antibodies to Babesia bovis and B. bigemina from close to birth up to 12 months of age.The results showed that infection with both parasites is widespread throughout the 3 zones. Many of the animals had produced antibody to both parasites by 6 months of age indicating high transmission rates resulting in enzootic stability for both parasites.Any changes to agricultural practices in the state that could affect disease stability through either reduction in numbers of tick vectors or the introduction of susceptible adults will have to be accompanied with measures such as vaccination to limit losses due to clinical babesiosis.     

Mecanismos de Desarrollo de la Cúpula en los Conductos Semicirculares de las Aves: II. Reorganizacion Celular

A light microscopic study of the epithelia of the crista ampullaris of the semicircular canals of the embryonic chicken indicates that the epithelial cells undergo irregular degenerative changes, with continual mitotic replacement of surface cells. The cupula develops over the surface epithelia through vesicular secretions containing acidophils fibrillar material mixed with globular formations derived from fragmentation of the surface epithelial cells. Electron microscopic studies demonstrate the mode of secretion of rounded or oval supraepithelial bodies from surface epithelium, contributing to the development of the cupula ampullaris. These observations provide evidence of cytoplasmic contributions of surface epithelial cells of the crista ampullaris contributing to the development and continued reorganization of the cupula ampullaris during embryonic development.     

Procedures for preventing transmission of foot-and-mouth disease virus (O/TAW/97) by people

The aim of this study was to determine personal hygiene protocols and animal avoidance periods needed to prevent transmission of FMDV (O/TAW/97). Forty-six, 9-week-old barrows free of FMDV were randomly allocated to five treatment groups and a control group. Investigators contacted and sampled FMDV-inoculated pigs for approximately 40 min and then contacted and sampled sentinel pigs after using no biosecurity procedures, washing hands and donning clean outerwear, or showering and donning clean outerwear. Personnel were sampled for nasal carriage of FMDV for 85.43 h. Contaminated personnel did not transmit FMDV to susceptible pigs after handwashing or showering, and donning clean outerwear. FMDV was transmitted when biosecurity procedures were not used. FMDV was not detected in nasal secretions of investigators. Thus, extended animal avoidance periods do not appear to be necessary to prevent transmission of FMDV (O/TAW/97) by people to pigs when organic material is removed through handwashing/showering and donning clean outerwear. This study supports similar findings in a previous publication using FMDV (O/UK/35/2001).