Reproductive and growth performance in Jin Hua pigs cloned from somatic cell nuclei and the meat quality of their offspring

Somatic cell cloning is expected to be a valuable method for conserving genetic resources in pigs. In this study, we compared the reproductive and growth performance of Jin Hua cloned pigs with that of naturally bred Jin Hua pigs. In addition, we generated offspring from the cloned sows and examined the productivity and quality of meat in the progeny. The birth weights and growth rates of somatic cell-cloned pigs were similar to those of Jin Hua pigs. The cloned pigs reached puberty very early, and this is typical of the Jin Hua breed. Furthermore, reproductive performance, in terms of traits such as gestation period, litter size, and raising rate in the cloned pigs were similar to Jin Hua pigs. Although the offspring of the cloned (OC) pigs had lower birth weights than the Jin Hua breed, the daily weight gain of the OC pigs was significantly higher, especially at the finishing stage. The carcass quality of the OC pigs had similar characteristics to the Jin Hua breed, namely thick back fat and a small loin area. Furthermore, the meat qualities of the OC pigs were similar to those of Jin Hua pigs in terms of intramuscular fat content and tenderness. These results demonstrate that cloned pigs and their offspring were similar to the Jin Hua breed in most of the growth, reproductive, and meat productive performances. This strongly suggests that pigs cloned from somatic cell nuclei have the potential to be a valuable genetic resource for breeding.     

Fine mapping of foxglove aphid (Aulacorthum solani) resistance gene Raso1 in soybean and its effect on tolerance to Soybean dwarf virus transmitted by foxglove aphid

Soybean dwarf virus (SbDV) causes serious dwarfing, yellowing and sterility in soybean (Glycine max). The soybean cv. Adams is tolerant to SbDV infection in the field and exhibits antibiosis to foxglove aphid (Aulacorthum solani), which transmits SbDV. This antibiosis (termed “aphid resistance”) is required for tolerance to SbDV in the field in segregated progenies of Adams. A major quantitative trait locus, Raso1, is reported for foxglove aphid resistance. Our objectives were to fine map Raso1 and to reveal whether Raso1 alone is sufficient to confer both aphid resistance and SbDV tolerance. We introduced Raso1 into cv. Toyomusume by backcrossing and investigated the degree of aphid antibiosis to foxglove aphid and the degree of tolerance to SbDV in the field. All Raso1-introduced backcross lines showed aphid resistance. Interestingly, only one Raso1-introduced backcross line (TM-1386) showed tolerance to SbDV in the field. The results demonstrated Raso1 alone is sufficient to confer aphid resistance but insufficient for SbDV tolerance. Tolerance to SbDV was indicated to require additional gene(s) to Raso1. Additionally, Raso1 was mapped to a 63-kb interval on chromosome 3 of the Williams 82 sequence assembly (Glyma1). This interval includes a nucleotide-binding site–leucine-rich repeat encoding gene and two other genes in the Williams 82 soybean genome sequence.     

Antimicrobial susceptibility of Escherichia coli isolated from feces of wild cranes migrating to Kagoshima, Japan

Susceptibility to 13 antimicrobial agents was examined for 138 Escherichia coli isolates obtained from 192 fecal samples of wild cranes that migrated for wintering to the Izumi plain, Kagoshima prefecture in Japan. The numbers of isolates that were resistant to the antimicrobials used in this study are as follows: oxytetracycline (OTC), 22 isolates; minocycline, 7 isolates; ampicillin (ABPC), 4 isolates; nalidixic acid, 4 isolates; enrofloxacin, 2 isolates; kanamycin, one isolate. Multidrug resistant isolates exhibiting 2-4 drug resistances were obtained. All of the OTC-resistant isolates carried either the tet (A) or tet(B) gene. The bla(TEM) gene was found in all of the ABPC-resistant isolates.     

Alternative BSE risk assessment methodology for beef and beef offal imported into Japan

The Food Safety Commission (FSC) of Japan, established in July 2003, has its own initiative to conduct risk assessments on food stuffs known as "self-tasking assessment". Within this framework, the FSC decided to conduct a risk assessment of beef and beef offal imported into Japan from countries with no previous BSE reports; thus, a methodology was formed to suit to this purpose. This methodology was partly based on the previous assessments of Japanese domestic beef and beef imported from U.S.A./Canada, but some modifications were made. Other organizations' assessment methods, such as those used for BSE status assessment in live cattle by the OIE and EFSA's GBR, were also consulted. In this review, the authors introduce this alternative methodology, which reflects (1) the risk of live cattle in the assessed country including temporal risks of BSE invasion and domestic propagation, with the assessment results verified by surveillance data, and (2) the risk of beef and beef offal consisting of cumulative BSE risk by types of slaughtering and meat production processes implemented and the status of mechanically recovered meat production. Other possible influencing factors such as atypical BSE cases were also reviewed. The key characteristic of the current assessment is a combination of the time-sequential risk level of live cattle and qualitative risk level of meat production at present in an assessed country.     

CONTRAST AGENT Gd‐EOB‐DTPA (EOB·Primovist®) FOR LOW‐FIELD MAGNETIC RESONANCE IMAGING OF CANINE FOCAL LIVER LESIONS

Contrast‐enhanced magnetic resonance (MR) imaging with a new liver‐specific contrast agent gadolinium‐ethoxybenzyl‐diethylenetriamine penta‐acetic acid (Gd‐EOB‐DTPA; EOB·Primovist®) was studied in 14 normal beagles and 9 dogs with focal liver lesions. Gd‐EOB‐DTPA accumulates in normally functioning hepatocytes 20 min after injection. As with Gd‐DTPA, it is also possible to perform a dynamic multiphasic examination of the liver with Gd‐EOB‐DTPA, including an arterial phase and a portal venous phase. First, a reliable protocol was developed and the appropriate timings for the dynamic study and the parenchymal phase in normal dogs using Gd‐EOB‐DTPA were determined. Second, the patterns of these images were evaluated in patient dogs with hepatic masses. The optimal time of arterial imaging was from 15 s after injection, and the optimal time for portal venous imaging was from 40 s after injection. Meanwhile, the optimal time to observe changes during the hepatobiliary phase was from 20 min after injection. In patient dogs, 11 lesions were diagnosed as malignant tumors; all were hypointense to the surrounding normal liver parenchyma during the hepatobiliary phase. Even with a low‐field MR imaging unit, the sequences afforded images adequate to visualize the liver parenchyma and to detect tumors within an appropriate scan time. Contrast‐enhanced MR imaging with Gd‐EOB‐DTPA provides good demarcation on low‐field MR imaging for diagnosing canine focal liver lesions.     

The effect of free and polyethylene glycol-liposome-entrapped albendazole on larval mobility and number in Toxocara canis infected mice

As part of our exploratory drug research on the larva migrans that causes roundworm in dogs and cats, this study was carried out to clarify the effect of free and liposome-entrapped (LE) albendazole in Toxocara canis infected mice. In infected mice, evaluation of mobility and number of larva were examined in detail in the brain, skeletal muscle and liver. Larva mobility was evaluated by using the relative mobility (RM) value. Albendazole was LE as one of the drug delivery systems (DDSs). Polyethylene glycol (PEG) was added to the liposome in order to avoid evoking a response by the reticuloendothelial system (RES). By using the albendazole PEG-LE delivery system, it was possible to target the larvae in the mouse brain and liver resulting in a decrease in the number of larvae. In the skeletal muscle of the infected mice, the intraperitoneal dosages of PEG-LE albendazole did not cause a complete decrease in the number of larvae, even though free albendazole did cause the number to decrease. Therefore, it is necessary to take into consideration the migrating stage of the larvae before the initiation of any drug administration.     

Polymorphisms of caprine PrP gene detected in Japan

Polymorphism of the PrP gene is a primary factor influencing susceptibility and incubation period in natural and experimental scrapie in sheep and goats. Polymorphisms of the caprine PrP gene in Japan were examined in 118 goats. Eight allelic variants and 19 genotypes were obtained. Amino acid polymorphisms were observed at 7 codons: 102, 142, 143, 240, 127, 146 and 211 (the latter 3 are novel polymorphisms). The polymorphisms at codons 142M and 143R, which are associated with the resistance to scrapie, were relatively rare in the present study. Thus, the present results provide information about the caprine PrP gene that may be useful for assessing the risk of goat scrapie.     

Development of Peyer's patch and cecal tonsil in gut-associated lymphoid tissues in the chicken embryo

It is well known that chicken B cells develop in the bursa of Fabricius (BF), which is categorized as gut-associated lymphoid tissue (GALT). Chicken GALT also includes Peyer's patch (PP) and cecal tonsil (CT). The relationship between these tissues in GALT during B cell development is currently unknown. In this study, we conducted comparative examination of PP, CT and BF development during embryogenesis using immunohistochemical staining. On day 13 of embryogenesis (E13), accumulation of MHC class II(+) cells was observed in the intestine. Thereafter, Bu-1(+) cells and IgM(+) cells appeared, and their number continuously increased at the same sites where MHC class II(+) cells were present. Similar results were obtained in the CT. The locations of embryonic PP were limited to two sites; near the Meckel's diverticulum and the ileocecal junction. Anlage of bursal follicles first appeared at E13 and developed thereafter. Immigration of Bu-1(+) cells to bursal follicles began at E13, and the number of Bu-1(+) cell subsequently increased. When the follicle of BF was eliminated from the embryo by treatment with testosterone, development of PP and CT were observed. We concluded therefore that the development of PP and CT start during late embryogenesis at the same time as the follicle of BF, and that appearance of surface IgM(+) cells in PP and CT is independent form the development of the follicle of BF.     

Reproductive characteristics of the feral raccoon (Procyon lotor) in Hokkaido,Japan

Reproduction of feral raccoons (Procyon lotor) in Hokkaido, Japan, was examined during a 2-year period by analysis of placental scars or fetuses in the uterus. Of 242 collected females, 69 (29%) were juveniles, 71 (29%) yearlings, and 102 (42%) adults. The pregnancy rate averaged 66% in yearlings and was significantly lower than the 96% average observed in adults (p<0.01). Litter size ranged from 1 to 7 offspring per female, and averaged 3.6 in yearlings and 3.9 in adults. There was no significant difference in mean litter size between yearlings and adults. In Hokkaido, the raccoon mating season peaked in February and the majority of litters were born between March and May, similar to patterns described in North America, but some females mated in summer. The reproductive potential of feral raccoons in Hokkaido was similar to that reported in North America. The recent increase in raccoon numbers can be explained by their high productivity. Harvest data suggest that hunting pressure on juveniles is lower than that for older age classes when using box traps in summer. In order to reduce the feral raccoon population, alternative hunting methods that increase juvenile mortality rates are needed.