Mitochondrial DNA analysis of Nepalese domestic dwarf cattle Lulu*

Dwarf Lulu cattle, the only Bos Taurus type of cattle in Nepal, are raised under severe environments in the mountainous zone of that country. In the present study, the body measurement traits, cytogenetic and molecular genetic characteristics of the Lulu cattle are investigated. Blood samples were collected from 31 animals in four villages (altitudes 2590–3550 m) in the southern part of Mustang. The Lulu cattle had a normal karyotype with 2n = 60, XY or XX. Only one male examined had a large submetacentric X‐chromosome and a small submetacentric taurine type Y‐chromosome. The mitochodrial DNA (mtDNA) genotypes were analyzed by PCR mediated restriction fragment length polymorphisms, displacement (D)‐loop region PCR mediated single strand conformation polymorphisms, and D‐loop region sequences. Many base substitutions were found in the D‐loop region, suggesting that the Lulu cattle originated from at least 10 maternal lines. Three types of mtDNA from these cattle were found, the Bos taurus type (n = 23), the Bos indicus type (n = 6), and the Bos grunniens type (n = 2). In the village at the lowest altitude, four of the five cows were of the Bos indicus type. These results indicated that mtDNA types of the Lulu cattle mostly belong to Bos taurus, but have been hybridized with Bos indicus cattle in lower‐elevation regions in their maternal lineage.     

Expression dynamics of bovine MX genes in the endometrium and placenta during early to mid pregnancy

MX belongs to a family of type I interferon (IFN)-stimulated genes, and the MX protein has antiviral activity. MX has at least two isoforms, known as MX1 and MX2, in mammals. Moreover, bovine MX1 has been found to have alternative splice variants—namely, MX1-a and MX1B. In ruminants, IFN-τ—a type I IFN—is temporarily produced from the conceptus before implantation and induces MX expression in the endometrium. However, the expression dynamics of MX after implantation are not clear. In the present study, we investigated the expression of MX1-a, MX1B and MX2 in the endometrium and placenta before and after implantation along with the expression of IFN-α, type I receptors (IFNAR1 and IFNAR2) and interferon regulatory factors (IRF3 and IRF9). Pregnant uterine samples were divided into five groups according to pregnancy days 14–18, 25–40, 50–70, 80–100, and 130–150. Tissue samples were collected from the intercaruncular endometrium (IC), caruncular endometrium (C) and fetal placenta (P). Although all the MX expressions were significantly higher in the IC and C at days 14–18, presumably caused by embryo-secreted IFN-τ stimulation, their expressions were also detectable in the IC, C and P after implantation. Furthermore, IFN-α expression was significantly higher in the IC. RT-PCR indicated IFNAR1, IFNAR2, IRF3 and IRF9 mRNA in all the tissues during pregnancy. These results suggest that all the MX genes are affected by the type I IFN pathway during pregnancy and are involved in an immune response to protect the mother and fetus.     

Epidemiological and bacteriological survey of buffalo mastitis in Nepal

A total of 355 Murrah cross buffaloes, consisting of 23 subclinical and 332 clinical mastitis cases brought to the Veterinary Teaching Hospital, Chitwan, Nepal from 2002 to 2005, were analyzed to determine the organisms involved, the seasonal occurrence of mastitis, and antibiotic susceptibility of mastitis pathogens. Coagulase negative Staphylococci (CNS) such as Staphylococcus albus and S. epidermidis were the predominant organisms associated with subclinical cases, and CNS and Coliforms in clinical cases. The maximum number (16%) of clinical cases of mastitis were observed in the month of July, when temperature and humidity are highest. The incidence of clinical mastitis was higher in animals during 1st calving and during the 1st month of parturition. Resistance to antibiotics was determined for 55, 23 and 149 isolates of Staphylococcus spp., Streptococcus spp. and Coliforms, respectively. In vitro drug sensitivity testing revealed that enrofloxacin had the highest average sensitivity (91%) for all types of bacteria. The effectiveness of other drugs detected were gentamicin (87%), tetracycline (83%) and chloramphenicol (82%). The antibiogram showed that both gentamicin and enrofloxacin are slowly becoming resistant. Mastitis pathogens have developed resistance to ampicillin and penicillin.     

Performance of Bangladesh indigenous rice in a weed infested field and separation of allelopathy from resource competition

This study aimed to identify the potential allelopathic indigenous rice (Oryza sativa L. ssp. indica) varieties from Bangladesh using a performance study in a weed‐infested field and to assess the extent of allelopathic interference relative to resource competition in a glasshouse experiment. Six varieties – namely, “Boterswar,” “Goria,” “Biron” and “Kartiksail” as the most allelopathic, “Hashikolmi” as weakly allelopathic and “Holoi” as nonallelopathic – were raised following a nonweed control method. The infestation levels of weed species were calculated using Simpson's Diversity Index (SDI), which ranged from 0.2 to 0.56. However, a significant correlation coefficient (0.87, P < 0.001) was obtained from these field data compared with the root inhibition percentage from the laboratory bioassay, and the “Boterswar” variety was the most allelopathic. The interactions between the allelopathic variety “Boterswar,” weakly allelopathic variety “Hashikolmi” and Echinochloa oryzicola via a target (rice)‐adjacent (E. oryzicola) cogrowth culture were determined in a hydroponic arrangement. The relative competitive intensity (RCI) and the relative neighbor effect (RNE) values showed that the crop–weed interaction was facilitation for “Boterswar” and competition for “Hashikolmi” and E. oryzicola in rice/E. oryzicola cogrowth cultures. The allelopathic effects of “Boterswar” were much higher than the resource competition in rice/E. oryzicola cogrowth cultures. The converse was observed for “Hashikolmi.” Moreover, the mineral content of E. oryzicola was severely affected by “Boterswar”/E. oryzicola cogrowth cultures’ exudate solution. Therefore, the allelopathic potential of “Boterswar” variety might be useful for developing the weed‐suppressing capacity of rice, which will likely have a significant influence on paddy weed control.     

Effects of tris(1,3-dichloro-2-propyl) phosphate on epididymal sperm parameters in adult male rats

Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) is widely used as a flame retardant and is known to exhibit anti-androgenic effects in vitro and in vivo. To assess the reproductive toxicity potency of TDCIPP, we investigated the effects of 7 days of TDCIPP oral administration on epididymal sperm motion and concentration in adult male Wistar–Imamichi rats. Thirty-five days after the final administration, sperm parameters were evaluated by computer-assisted sperm analysis. Results showed that sperm swimming progression and vigor and sperm concentration in TDCIPP-treated rats were unexpectedly higher than those in control rats. TDCIPP did not significantly affect the percentage of motile sperms or sperm swimming pattern. These results contribute to the understanding of the biological effects of TDCIPP.     

Beneficial effects on meat quality of yellowtail Seriola quinqueradiata induced by diets containing red pepper

The meat quality of farmed yellowtail Seriola quinqueradiata fed on extruded pellets (EP) containing 0.5% (v/v) red pepper (experimental group) was compared with yellowtail of the same age fed on EP (control group). In 1-year-old yellowtail, the crude lipid content of the dorsal muscle of the experimental group tended to be lower than that of the control group. In contrast, there was no difference in the lipid content of the dorsal muscle between the control group and the experimental group in 2-year-old yellowtail. The muscle texture of the experimental group was significantly firmer than that of the control group, with the effect of red pepper unrelated to fish age and lipid content. Color change of red muscle of the experimental group was significantly lower than that of the control group, and the content of thiobarbituric acid-reactive substances in the red muscle was significantly lower in the experimental group than in the control group. These results are the first to demonstrate that the inclusion of red pepper in the diet is able to reduce the loss of muscle texture firmness and to slow down color change in red muscle of yellowtail.     

Effects of Yuzu (Citrus junos) Peel from Waste as an Aquaculture Feed Supplement on Growth,Environmental Load,and Dark Muscle Discoloration in Yellowtail Seriola quinqueradiata

Beneficial utilization of yuzu (Citrus junos) peel was investigated to improve the commercial value of cultured yellowtail fish. The antioxidant effects of grated yuzu peel from pomace (yuzu paste) on prevention of dark muscle discoloration during storage in sliced yellowtail fish were tested. Four diets were prepared, containing 0, 10, 50, and 100 g yuzu paste in a 1,450-g diet (wet basis). Fish were fed one of the four diets for 10 weeks. Growth performance was not significantly different among the dietary groups, but fish fed a diet containing 100-g yuzu paste showed the least average body weight and a significant increase in fecal amount and fat levels in the feces, which suggest low digestibility and low absorption. Dark muscle discoloration was significantly reduced in all yuzu dietary groups compared to the control group during storage at 4°C. The optimal supplementation of yuzu paste in the fish diet is very effective at maintaining fish flesh freshness as a finishing diet without causing additional phosphorus or nitrogen pollution of the sea and inhibiting fish growth. This study provides a new way to utilize waste yuzu peel, which also helps reduce waste from yuzu processing.     

Relationship between Mucosal Barrier Function of the Oviduct and Intestine in the Productivity of Laying Hens

The mucosa of the intestine and oviduct of hens are susceptible to pathogens. Pathogenic infections in the mucosal tissues of laying hens lead to worsened health of the host animal, decreased egg production, and bacterial contamination of eggs. Therefore, better understanding of the mechanisms underlying mucosal barrier function is needed to prevent infection by pathogens. In addition, pathogen infection in the mucosal tissue generally causes mucosal inflammation. Recently, it has been shown that inflammation in the oviduct and intestinal tissue caused by disruption of the mucosal barrier function, can affect egg production. Therefore, it is vitla to understand the relationship between mucosal barrier function and egg production to improve poultry egg production. This paper reviews the studies on (1) oviductal mucosal immune function and egg production, (2) intestinal inflammation and egg production, and (3) improvement of mucosal immune function by probiotics. The findings introduced in this review will contribute to the understanding of the mucosal barrier function of the intestine and oviduct and improve poultry egg production in laying hens.     

Relative parasitic fitness of isolates of Pyricularia oryzae Cav. with different sensitivities to fungicides

The relative parasitic fitness of isolates of Pyricularia oryzae with different sensitivities to isoprothiolane (di-isopropyl 1,3-dithiolan-2-ylidenemalonate) and IBP (S-benzyl O, O-di-isopropyl phosphorothioate) was studied in the absence of fungicides. Four field isolates (S-1,S-2,MR-1 and MR-2) and two in-vitro mutants (Rvt-1 and Rvt-2) were used for disease epidemics. S-l and S-2 were wild types; MR-1 and MR-2 were sensitive to isoprothiolane and moderately resistant to IBP, and Rvt-1 and Rvt-2 were resistant to both fungicides. Twelve epidemics were made by inoculating rice seedlings with mixed conidial suspensions of two isolates or mutants. The value of relative parasitic fitness (W = 0-1.0) was calculated for each isolate and epidemic. S-l and S-2 were stronger (W = 1.0) than MR-2, Rvt-1 and Rvt-2; but weaker (W = 0.75, 0.73, respectively) than MR-1. MR-1 was strongest among all isolates and mutants used. MR-2 was slightly weaker (W = 0.9-1.0) than S-l and S-2, but stronger than Rvt-1 and Rvt-2. Rvt-1 and Rvt-2 had smaller values of W, ranging from 0.25-0.58, in the epidemics with each field isolate. These results suggest that the proportions of in-vitro mutants do not increase unless intensive selection pressure is given, and would be expected to decrease rapidly after the selection pressure is removed. Isolates moderately resistant to IBP, such as MR-1 and MR-2, however, had high values of W, suggesting that they would increase or would not decrease rapidly in the absence of selection pressure. These results may well explain why isolates highly resistant to isoprothiolane and IBP have seldom been found, and why a large number of isolates moderately resistant to IBP but sensitive to isoprothiolane have been observed in the field.