Acceptance by stoats (Mustela erminea) of 1080 (sodium monofluoroacetate) in small-volume baits and its effect on behaviour and time to death

AIMS: To assess whether stoats (Mustela erminea) would eat small baits containing 0.1% sodium monofluoroacetate (1080); whether they would die from it; how long it would take to kill them; and to document the behaviour of 1080-intoxicated stoats.

METHODS: Stoats were offered 1-g baits of two semi-fluid formulations containing 0.1% 1080, presented in open dishes, and their subsequent behaviour was monitored by video and direct observation. Muscle samples from stoats that died were analysed for 1080 residues.

RESULTS: There was no significant difference between two types of bait with regard to acceptance, mortality, and time to death, and behavioural effects were similar; consequently, results from the two types of bait were combined. Twelve of 14 stoats offered the baits ate them voluntarily, and a 13th licked bait off its fur; all 13 died between 1 h 15 min and 4 h 7 min (mean 2 h 38 min) later. At first (range 29 min — 2 h 7 min, mean 1 h 1 min), their behaviour appeared to be normal. Ataxia and hyperactivity were the first behavioural signs of poisoning, and lasted 2 min — 1 h 40 min (mean 26 min). This was followed by recumbency with convulsions and rapid breathing (range 16 min to 2 h, mean 58 min), then recumbency with limited activity and progressively shallow breathing prior to death (range 1–51 min, mean 33 min). Stoats became non-responsive to a light being turned on, or to touch once recumbency became sustained.

Residues of 1080 were found in muscle tissue of all 13 dead stoats, at concentrations ranging from 0.075 μg/g in a 287-g male that died 4 h 7 min after eating only 0.74 g of bait, to 2.5 μg/g in a 254-g female that died 2 h 42 min after taking a whole 1-g bait.

CONCLUSION: Stoats will voluntarily take small (1-g) baits containing a lethal dose of 1080 at 0.1%, and die from it comparatively rapidly for a mammalian carnivore.     

Evolution of the pili nut genus (<Emphasis Type="Italic">Canarium</Emphasis> L., Burseraceae) and its cultivated species

Seeds from species of Canarium L. (Burseraceae) have been recommended as a potential nut crop for global trade that, if adopted, would be the first ‘new’ nut commodity since the introduction of the Macadamia nut in the early 20th century. The present study addresses several knowledge gaps about the evolutionary biology of Canarium species in order to explore their phylogeny and cultivation history in greater detail. The phylogeny of select Canarium species (16 spp.) from the three taxonomic sections of the genus was reconstructed using DNA sequence data from seven regions and included cultivated species C. album (Lour.) Raeusch., C. decumanum Gaertn., C. harveyi Seem., C. indicum L., C. ovatum Engl., C. tramdenum C.D. Dai et Yakovlev, and C. vulgare Leenh.. Sequence data from the nuclear genome (rDNA external transcribed spacer (ETS), the third intron of nitrate reductase (NIA-i3)) and the chloroplast genome (rbcL, rps16 intron, psbA-trnH spacer, trnL intron and trnL-F spacer) were analyzed using parsimony and Bayesian inference. Results indicate that Canarium comprises at least two distantly related evolutionary lineages within its tribe, desirable fruit characteristics of cultivated and wild-harvested edible species have evolved multiple times, and autopolyploidization rather than allopolyploidization may have been associated with speciation in Canarium sensu stricto. The markers ETS, NIA-i3, rps16 intron, and psbA-trnH spacer will provide the most informative variation for future expanded studies of Canarium phylogeny, although detailed morphological study and taxonomic revision of the genus will be necessary as well.     

Levels of mortality in hens by end of lay on farm and in transit to slaughter in Great Britain

The average mortality for end of lay hens dead on arrival (DOA) was 0.27 per cent (median 0.15 per cent) in a survey of 13.3 million hens transported during 2009. A statistical model of the data indicated main risk factors for DOA to be slaughter plant, distance travelled and external air temperature, with longer journeys and low external air temperatures increasing the risk. Other highly significant risk factors (P<0.001) related to the condition of the birds on farm, where an increased risk of DOA was positively associated with poor feather cover, lower body weight, cumulative mortality of the flock and poor health (indicated by a high proportion of the load rejected at the plant for traumatic injury and disease state). However, the data indicate that by taking risk factors into consideration it is possible to transport hens up to 960 km with low losses in temperate conditions. Mean levels of on-farm mortality, during the laying period, for a total of 1486 flocks were significantly lower in cages (5.39 per cent) than in barn (8.55 per cent), free-range (9.52 per cent) or organic flocks (8.68 per cent) according to producer records a median of seven days before depopulation, with considerable variation between flocks in all systems.     

Evidence of aberration of the natural cytotoxic cell activity in Fundulus heteroclitus (Pisces: Cyprinodontidae) from the Elizabeth River, Virginia

There is a general agreement that exposure to high concentrations of polynuclear aromatic hydrocarbons (PAH) in sediments is associated with high frequencies of neoplasms in feral fish species. Since PAH modulate the activity of murine and amphibian natural cytotoxic (killer) cells, a leukocyte subpopulation that is believed to play an important role in immunosurveillance, we wished to determine if fish exposed to PAH could have an altered natural cytotoxic cell (NCC) activity. In the present study, mummichog (Fundulus heteroclitus L.) were collected from two sites in the Elizabeth River, VA that are heavily contaminated with PAH, and from a relatively unpolluted reference site in the York River, VA. The cytotoxic activity of anterior kidney and splenic leukocytes was tested against the tumor cell line K562. The leukocytes from Elizabeth River fish displayed a significant depression of the in vitro tumorilytic activity as compared with leukocytes from the York River fish. Analysis of leukocyte-tumor cell conjugates indicated that Elizabeth River fish leukocytes were unable to recognize and subsequently bind to the tumor target cells. This suggests an aberration in the early events of the cytotoxic mechanism. By keeping the fish in cleaner York River water for up to 28 weeks the suppressed NCC activity was reversed totally in one site, which is slightly contaminated, and partially in the other site, which is heavily polluted with creosote from an operating wood treatment plant. This indicates that the decreased NCC activity was related, at least in part, to exposure to the chemical pollutants in the Elizabeth River sediments.     

Comparison of two DNA extractions and nested PCR, real-time PCR, a new commercial PCR assay, and bacterial culture for detection of Mycobacterium avium subsp. paratuberculosis in bovine feces.

In this study, 5 combinations of 2 DNA extractions and 3 polymerase chain reaction (PCR) techniques were compared with culture for the detection of Mycobacterium paratuberculosis directly from bovine feces. These combinations included a new commercial extraction technique combined with a commercial PCR/Southern blot technique, nested PCR (nPCR), or real-time PCR, and a university-developed extraction combined with nPCR or real-time PCR. Four of the 5 combinations had statistically similar sensitivities between 93% and 100% and specificity between 95% and 100%, when compared with culture results from 63 bovine fecal samples. These results indicated that using a commercial extraction with a commercial PCR/Southern blot, nPCR, or real-time PCR, or a university-developed extraction with real-time PCR would result in similar sensitivities to culture for the identification of M. paratuberculosis from bovine feces and are valid alternatives to culture.