Blood and liver biopsy for the non‐destructive screening of tilapia lake virus     

Chutipong Chiamkunakorn  Vimbai Irene Machimbirike  Saengchan Senapin  Pongsak Khunrae  Ha Thanh Dong  Triwit Rattanarojpong 《Journal of fish diseases》2019,42(11):1629-1636

Detection of tilapia lake virus (TiLV) in tilapines is mainly from visceral organs of killed fish. However, lethal sampling might not be viable to broodstock and economically important ornamental cichlids. To contribute towards screening of the virus in asymptomatic infected fish, a subclinically infected population of Nile tilapia adults obtained from a local farm was preliminarily tested to compare different non‐lethal sampling methods, for example liver biopsy, gill biopsy, fin clip, mucus, faeces and blood for detection of TiLV. Only liver and blood samples gave positive results by PCR. Since blood sampling is relatively simpler, it was further used for five naturally co‐cultured juvenile fish species from above‐mentioned farm including 40 red tilapia broodstock and 20 Nile tilapia adults from two other different farms. The results showed that from the tested fish, 4 of 5 Nile tilapia, 2 of 5 hybrid red tilapia and 3 of 5 giant gourami blood samples tested positive, while 38 of 40 blood samples of red tilapia tested positive for TiLV in second‐step PCR. Sequencing representative PCR amplicons of positive samples confirmed sequence identity to TiLV. In conclusion, both blood and liver biopsy are practical non‐destructive sampling platforms for TiLV screening in cichlids with blood being more convenient, especially for tilapia broodstock.  相似文献   

Population recovery patterns of Southeast Asian ungulates after poaching     

Robert Steinmetz  Wanlop Chutipong  Erb Chirngsaard 《Biological conservation》2010,143(1):42-51

Large ungulate populations in Southeast Asia have collapsed due to commercial poaching, but little is known about patterns of population recovery after poaching has been controlled. Using a sign-based index of abundance, we measured 6-year trends in abundance and habitat use of five ungulate species after poaching ceased at a site in Thailand. Regression slopes of annual indices against time indicated population growth rates (r) of 0.44 and 0.31 for muntjac (Muntiacus muntjak) and gaur (Bos gaurus), respectively—close to the intrinsic rates of natural increase for similarly-sized ungulates. Thus, muntjac and gaur can recover relatively rapidly from low population levels. In contrast, sambar (Cervus unicolor) remained consistently rare despite freedom from hunting, perhaps because prime males had been selectively targeted for trophies, disrupting the species mating system. Wild pigs (Sus scrofa) were already relatively abundant when monitoring started, illustrating their resilience to hunting and ability to quickly recolonize disturbed areas. Gaur herds (the key demographic unit of the population) and muntjac consistently selected deciduous over evergreen forest as their populations increased, revealing the importance of food-rich deciduous forest in driving recovery of these species. The unexpected failure of sambar to recover suggests that reproductive behavior may override seemingly positive interventions (i.e., stopping poaching) that reduce mortality. Small but well-protected recovery zones set within forested areas might help propel population recovery of ungulates and increase the prey base for endangered tigers.  相似文献   

Heritability of,and genotypic correlations between,aflatoxin traits and physiological traits for drought tolerance under end of season drought in peanut (Arachis hypogaea L.)     

Teerayoot Girdthai  Sanun Jogloy  Nimitr Vorasoot  Chutipong Akkasaeng  Sopone Wongkaew  C. Corley Holbrook  Aran Patanothai 《Field Crops Research》2010

More rapid progress in breeding peanut for reduced aflatoxin contamination should be achievable with a better understanding of the inheritance of, aflatoxin trait and physiological traits that are associated with reduced contamination. The objectives of this study were to estimate the heritability of aflatoxin traits and genotypic (r_G) and phenotypic (r_P) correlations between drought resistance traits and aflatoxin traits in peanut. One hundred-forty peanut lines in the F_4:6 and F_4:7 generations were generated from four crosses, and tested under well-watered and terminal drought conditions. Field experiments were conducted under the dry seasons 2006/2007 and 2007/2008. Data were recorded for biomass (BIO), pod yield (PY), drought tolerance traits [harvest index (HI), drought tolerance index (DTI) of BIO and PY, specific leaf area (SLA), and SPAD chlorophyll meter reading (SCMR)], and aflatoxin traits [seed infection and aflatoxin contamination]. Heritabilities of A. flavus infection and aflatoxin contamination in this study were low to moderate. The heritabilities for seed infection and aflatoxin contamination ranged from 0.48 to 0.58 and 0.24 to 0.68, respectively. Significant correlations between aflatoxin traits and DTI (PY), DTI (BIO), HI, biomass and pod yield under terminal drought conditions were found (r_P = −0.25** to 0.32**, r_G = −0.57** to 0.53**). Strong correlations between SLA and SCMR with A. flavus infection and aflatoxin contamination were also found. Positive correlations between SLA at 80, 90, and 100 DAP and aflatoxin traits were significant (r_P = 0.13** to 0.46**, r_G = 0.26** to 0.81**). SCMR was negatively correlated with aflatoxin traits (r_P = −0.10** to −0.40**, r_G = −0.11** to −0.66**). These results indicated that physiological-based selection approaches using SLA and SCMR might be effective for improving aflatoxin resistance in peanut.  相似文献