Laboratory and field evaluation of flocoumafen for rodent control

A new anticoagulant rodenticide, flocoumafen, at a concentration of 0·005% in the bait in 24 h no-choice and 48 h choice laboratory feeding tests was found to cause 100% mortality of the Indian bush rat Golunda ellioti, the Indian gerbil Tatera indica and the soft-furred field rat Rattus meltada. In field trials in sugar cane and wheat, where these species and the Indian mole rat Bandicota bengalensis and Mus spp. were present, about 65% rodent control was obtained with a single treatment with 0·005% flucoumafen bait at the rate of 1 kg/ha. The performance of a single treatment with flocoumafen was comparable with that of 2·4% zinc phosphide, a conventional acute rodenticide. Unlike zinc phosphide, however, two treatments with a 10-day interval with flocoumafen resulted in significantly higher rodent control compared with the single treatment, indicating the superiority of flocoumafen over zinc phosphide in repeat baiting treatments.     

溴敌隆防治高原鼠兔和高原鼢鼠的研究

溴敌隆(Bromadiolone)是近年来新出现的第二代抗凝血杀鼠剂中的一个新品种,最近已在欧洲各国、加拿大、美国市场上出售。青海省化工科研设计所在国内首先合成。     

Zinc phosphide intoxication of wild turkeys (Meleagris gallopavo)

Zinc phosphide (Zn3P2) is a rodenticide used to control a variety of small mammal species. It is available over-the-counter or as a restricted-use pesticide depending on how it is to be applied. The toxicity of Zn3P2 is dependent on the species exposed, whether the animal is able to vomit or not, and whether it is ingested on a full or empty stomach. Nontarget species can be exposed through inadvertent or intentional product misapplication. In this article we describe four mortality events in which wild turkeys (Meleagris gallopavo) were believed to have been intoxicated following the ingestion of baits containing Zn3P2.     

Evaluation of the palatability and toxicity of candidate baits and toxicants for mongooses (<Emphasis Type="Italic">Herpestes auropunctatus</Emphasis>)

The small Indian mongoose (Herpestes auropunctatus) is an invasive pest species responsible for damage to native avian, reptile, and amphibian species on Hawaii, Croatia, Mauritius, and several Caribbean Islands, among other regions. Mongoose control has been pursued through a variety of means, with varying success. One toxicant, diphacinone, has been shown to be effective in mongooses and is co-labeled in a rodenticide bait for mongoose control in Hawaii; however, preliminary observations indicate low performance as a mongoose toxicant due likely to poor consumption. We evaluated the efficacy and palatability of 10 commercial rodenticide baits, technical diphacinone powder, and two alternative acute toxicants against mongooses in laboratory feeding trials. We observed poor acceptance and subsequent low overall mortality, of the hard grain-based pellets or block formulations typical of most of the commercial rodenticide baits. The exception was Tomcat® bait blocks containing 0.1% bromethalin, an acute neurotoxin, which achieved up to 100% mortality. Mortality among all other commercial rodenticide formulations ranged from 10 to 50%. Three-day feedings of 0.005% technical diphacinone formulated in fresh minced chicken achieved 100% mortality. One-day feedings of para-aminopropiophenone (PAPP), a chemical that reduces the oxygen-carrying capacity of the blood, achieved 100% mortality at concentrations of 0.10 to 0.15%. Bait acceptance of two sodium nitrite formulations (similar toxic mode of action as PAPP) was relatively poor, and mortality averaged 20%. In general, commercially produced rodenticide baits were not preferred by mongooses and had lower mortality rates compared to freshly prepared meat bait formulations. More palatable baits had higher consumption and achieved higher mortality rates. The diphacinone bait registered for rat and mongoose control in Hawaii achieved 20% mortality and was less effective than some of the other commercial or candidate fresh bait products evaluated in this study.     

Effects of H-2 and vitamin A on micrognathia in congenic mice.

Pregnant mice congenic with C57BL/10 (B10.A, B10.BR, B10.D2, B10.A(2R), B10.A(5R), B10.A(15R), B10.A(1R), B10.A(18R), and B10.OL) were fed Purina Mouse Chow or the same diet plus 200 IU of vitamin A daily. The pregnant dams were sacrificed on the eighteenth day of gestation, and the fetuses were sexed and examined for defects in mandibular development. On average, micrognathia occurred five times more frequently in female (1.5%) than male (0.3%) fetuses. The addition of vitamin A to the diet affected only females, reducing the frequency of this defect to that observed in males from dams fed the control diet. Micrognathia was strongly associated with micro- or anophthalmia, but not with defects of the palate. C57BL/10 fetuses had the highest frequency of micrognathia (3.2%) and B10.D2 and B10.A(5R) fetuses had the lowest (0.1%). The results suggest that a locus distal to C4 and perhaps proximal to Qa-1 may exert a moderate influence on mandibular development and a second locus proximal to E beta may have a weak effect.     

Phosphine-induced oxidative damage in rats: attenuation by melatonin

Phosphine (PH(3)), from hydrolysis of aluminum, magnesium and zinc phosphide, is an insecticide and rodenticide. Earlier observations on PH(3)-poisoned insects, mammals and a mammalian cell line led to the proposed involvement of oxidative damage in the toxic mechanism. This investigation focused on PH(3)-induced oxidative damage in rats and antioxidants as candidate protective agents. Male Wistar rats were treated ip with PH(3) at 2 mg/kg. Thirty min later the brain, liver, and lung were analyzed for glutathione (GSH) levels and lipid peroxidation (as malondialdehyde and 4-hydroxyalkenals) and brain and lung for 8-hydroxydeoxyguanosine (8-OH-dGuo) in DNA. PH(3) caused a significant decrease in GSH concentration and elevation in lipid peroxidation in brain (36-42%), lung (32-38%) and liver (19-25%) and significant increase of 8-OH-dGuo in DNA of brain (70%) and liver (39%). Antioxidants administered ip 30 min before PH(3) were melatonin, vitamin C, and beta-carotene at 10, 30, and 6 mg/kg, respectively. The PH(3)-induced changes were significantly or completely blocked by melatonin while vitamin C and beta-carotene were less effective or inactive. These findings establish that PH(3) induces and melatonin protects against oxidative damage in the brain, lung and liver of rats and suggest the involvement of reactive oxygen species in the genotoxicity of PH(3).     

Tetraene and pentaene leukotrienes: selective production from murine mastocytoma cells after dietary manipulation

A neoplastic mast cell tumor was grown in mice which had been raised since birth on a diet enriched with eicosapentaenoic acid. Intact harvested mastocytoma cells were stimulated with calcium ionophore A23187 to produce lipoxygenase products from the polyunsaturated fatty acids liberated from the cellular membranes. Leukotriene B4, B5, C4, and C5 were isolated and characterized by HPLC retention time, ultraviolet absorption spectrometry and mass spectrometry. The arachidonic acid content of the mast cell tumor lipids was altered from 9.2 to 3.9 mole % while eicosapentaenoic acid increased from 0.5 to 4.5 mole % in response to the fish oil-supplemented diet. The relative amounts of arachidonic and eicosapentaenoic acids (3.9 and 4.5 mole % respectively) were associated with similar amounts of LTB4 and LTB5 synthesized by the cells. These results suggest that the epoxide leukotriene (LIA) derivative can be made efficiently from either arachidonic or eicosapentaenoic acids when both are present in cellular lipids. In contrast, the ratio of LTC4 to LTC5 (10 to 1) indicates that the reaction of LTA with glutathione may be critically dependent upon the structure of the unsaturated fatty acid with the ratio of LTC4/LTB4 (2.0) more than 10 times greater than that (0.16) for LTC5/LTB5.     

The influence of sex and strain on trace element dysregulation in the brain due to diet-induced obesity

BackgroundThe objective of this study was to identify interaction effects between diet, sex, and strain on trace element dysregulation and gene expression alterations due to diet-induced obesity (DIO) in the hippocampus, striatum, and midbrain.MethodsMale and female C57BL/6 J (B6 J) and DBA/2 J (D2 J) mice were fed either a low fat (10 % kcal) diet (LFD) or high fat (60 % kcal) diet (HFD) for 16 weeks, then assessed for trace element concentrations and gene expression patterns in the brain.ResultsIn the hippocampus, zinc was significantly increased by 48 % in D2 J males but decreased by 44 % in D2 J females, and divalent metal transporter 1 was substantially upregulated in B6 J males due to DIO. In the striatum, iron was significantly elevated in B6 J female mice, and ceruloplasmin was significantly upregulated in D2 J female mice due to DIO. In the midbrain, D2 J males fed a HFD had a 48 % reduction in Cu compared to the LFD group, and D2 J females had a 37 % reduction in Cu compared to the control group.ConclusionsThe alteration of trace element homeostasis and gene expression due to DIO was brain-region dependent and was highly influenced by sex and strain. A significant three-way interaction between diet, sex, and strain was discovered for zinc in the hippocampus (for mice fed a HFD, zinc increased in male D2 Js, decreased in female D2 Js, and had no effect in B6 J mice). A significant diet by sex interaction was observed for iron in the striatum (iron increased only in female mice fed a HFD). A main effect of decreased copper in the midbrain was found for the D2 J strain fed a HFD. These results emphasize the importance of considering sex and genetics as biological factors when investigating potential associations between DIO and neurodegenerative disease.     

the effect of the combination of microbial phytase and amino acid supplementation of diets for finishing pigs on p and n excretion and carcass quality

The objective of this study was to evaluate the effect of a combined low-protein, low-phosphorus diet supplemented with limiting amino acids and microbial phytase on performance, nutrient utilization and carcass characteristics of late-finishing barrows. 4?×?8 crossbreed barrows were continuously housed in metabolism cages from 70?–?110?kg BW and were fed diets, either conventional (A) or protein reduced (B) or protein and phosphorus reduced diets (C) based on barley, maize and soybean meal. Diet A (positive control) contained in air dry matter 13% and 10% CP as well as 0.49% and 0.42% P at growth phases I (70?–?100?kg BW) or II (100?–?110?kg BW), respectively. Diet B was low in CP (11.3%, 8.4%), diet C low in CP and low in P (CP: as B, P: 0.36%, 0.30%). To diet B the limiting amino acids lysine, methionine, threonine and trypthophan were added to meet the levels in diet A. To diet C the limiting amino acids and 800 FTU/kg Aspergillus-phytase were supplemented. At the end of the balance periods the barrows were slaughtered, the carcasses scored and loin chops, ham and Phalanx prima IV were analysed for nutrients and minerals. The CP or P reduction in diets B and C did not generally negatively affect growth, feed efficiency, absolute nitrogen retention or overall carcass performances of the pigs. With the low CP diets B and C, N excretion per unit BWG was decreased by about 23%. The addition of microbial phytase (diet C) increased apparent total tract digestibility of P by about 20%. In spite of 30% reduction of P intake (diet C), the absolute P retention related to 1?kg BW did not differ between treatments. Thus, phytase supplementation in diet C reduced P excretion per unit BWG by about 33%. Phytase raised apparent digestibility of Zn by about 20% but not Ca digestibility. Generally the carcass traits and meat characteristics were not affected by any of the diet strategies. Mineralization of the Phalanx prima IV was also similar in all treatment groups. However, phytase supplementation led to significantly increased zinc concentration in bones (25%). In contrast, Fe incorporation into the Phalanx prima IV was not affected. In general, the feeding regimen introduced in this experiment offers substantial benefits in maintaining a sustainable environmental-friendly pork production even at the stage of late-finishing barrows.     

Effects of H-2 and vitamin A on eye defects in congenic mice.

Pregnant mice congenic with C57BL/10 (B10.A, B10.BR, B10.D2, B10.A(2R), B10.A(5R), B10.A(15R), B10.A(1R), B10.A(18R), and B10.OL) were fed Purina Mouse Chow or the same diet plus 200 IU of vitamin A daily. The pregnant dams were sacrificed on the 18th day of gestation and the fetuses were sexed and examined for defects in eye development. It was found that the frequency of microphthalmia and anophthalmia in the female progeny of mice fed Mouse Chow was 7.4-9.2% in B10.A and B10.BR, 4.0-5.5% in B10.A(18R), B10, B10.A(5R), B10.A(1R), B10.A(15R), and B10.A(2R), and 0.8% and 1.4% in B10.D2 and B10.OL mice, respectively. On average, the frequency of these defects in the female progeny was 6.2 times greater than that in males (P less than 0.001). The right eye was 5.8 times more often affected than the left (P less than 0.001). The addition of vitamin A to the diet increased the frequency of these eye abnormalities in all strains, suggesting that this effect is not mediated by loci associated with H-2, as is the case with vitamin A-enhanced cleft palate. The addition of vitamin A to the diet did not affect the ratios of affected males to females, affected right to left eye, or microphthalmia to anophthalmia. The results suggest that there are two loci on chromosome 17, one centromeric to E beta and one telemeric to C4, that interact to determine to some degree the frequency of microphthalmia and anophthalmia.     

Interaction of zinc ions with arsanilazotyrosine-248 carboxypeptidase A

The interaction between arsanilazotyrosine-248 carboxypeptidase A ([(Azo-CPD)Zn]) and excess zinc ions has been studied by stopped-flow and spectrophotometric methods at pH 8.2 and 7.7, I = 0.5 M (NaCl), and 25 degrees C. When excess zinc ions bind to arsanilazotyrosine-248 carboxypeptidase A, the characteristic red color, which arises from the intramolecular complex of the arsanilazotyrosine-248 residue with the active site zinc of the enzyme, changes to yellow with the inhibition of peptidase activity of the enzyme. Excess zinc ions have two binding sites for arsanilazotyrosine-248 carboxypeptidase A, and the binding constants of the first site (3.9 X 10(5) M-1 at pH 8.2; 7.1 X 10(4) M-1 at pH 7.7) are much larger than those of the second site (1.8 X 10(3) M-1 at pH 8.2; 7 X 10(2) M-1 at pH 7.7). The binding of excess zinc ions to the first site is completely correlated with the inhibition of the enzyme peptidase activity and the color change of the enzyme. The results can be understood in terms of zinc ions reacting with only one of three conformational states of arsanilazotyrosine-248 carboxypeptidase A [Harrison, L. W., Auld, D. S., & Vallee, B. L. (1975) Proc. Natl. Acad. Sci. U.S.A. 72, 4356].(ABSTRACT TRUNCATED AT 250 WORDS)     

Intoxication of nontarget wildlife with rodenticides in northwestern Kansas

The perception of prairie dogs (Cynomys spp.) both as a nuisance species and a keystone species presents a significant challenge to land, livestock, and wildlife managers. Anticoagulant and nonanticoagulant rodenticides are commonly employed to control prairie dog populations throughout their range. Chlorophacinone, and to a lesser extent zinc phosphide, are widely used in northwestern Kansas for controlling black-tailed prairie dog (Cynomys ludovicianus) populations. Although zinc phosphide poisoning of gallinaceous birds is not uncommon, there are few published accounts of nontarget chlorophacinone poisoning of wildlife. We report three mortality events involving nontarget rodenticide poisoning in several species, including wild turkeys (Meleagris gallopavo), a raccoon (Procyon lotor), and an American badger (Taxidea taxus). This includes the first documentation of chlorophacinone intoxication in wild turkeys and an American badger in the literature. The extent of nontarget poisoning in this area is currently unknown and warrants further investigation.     

Two proteins purified from lobster nerve extract; isolation and physicochemical characterization

1. A protein component, fraction B, of lobster nerve extracts has been isolated and purified by differential ultracentrifugation and precipitation with zinc acetate. 2. Physicochemical data obtained from this protein and from fraction C are summarized. 3. Fraction B is present in lobster nerve extracts in higher concentration (relative to fraction A) than in blood. 4. A second component, fraction C, of sedimentation constant S(20) (o) = 13.2 has been isolated from lobster nerve extracts.     

Supplemental zinc and vitamin A can alleviate negative effects of heat stress in broiler chickens

This experiment was conducted to evaluate the effects of zinc (ZnSO₄H₂O) and vitamin A (retinol) supplementation on performance, carcass characteristics, and serum concentrations of glucose, cholesterol, total protein, and malondialdehyde (MDA) as an indicator of lipid peroxidation in broiler chickens (Ross) reared at a high temperature (34°C). One hundred twenty 10-d-old male broilers were randomly assigned to 4 treatment groups, 3 replicates of 10 birds each. The birds were fed either a basal diet or the basal diet supplemented with either 30 mg Zn/kg diet, 4.5 mg (15,000 IU) retinol/kg diet, or 30 mg Zn+4.5 mg retinol/kg diet. Supplemental zinc and vitamin A significantly increased live weight gain and improved feed efficiency (p<0.05). However, a combination of zinc and vitamin A, rather than each separately, provided a greater performance. Hot and chilled carcass weights and yields and the weights of internal organs with the exception of abdominal fat were greater for each supplement (p<0.05) compared to the control group. Abdominal fat decreased (p<0.05) upon dietary zinc and vitamin A supplementation. Supplemental treatments resulted in an increased total serum protein but decreased glucose, cholesterol, and MDA concentrations. The results of the study show that, separtely or as a combination, zinc and vitamin A supplementation resulted in an improved live weight gain, feed efficiency, and carcass traits, as well as a decrease in serum MDA concentrations. The results of the present study also suggest that zinc and vitamin A have similar effects and that a combination of zinc and vitamin A may offer a potential protective management practice in preventing heat-stress-related depression in performance of broiler chickens.     

Protein malnutrition and response of pancreatic acinar cells to stimulation by cholecystokinin

Pancreatic lobules were isolated from 2 groups of male Wistar rats after 23 days of diet. A control group (C) fed on a 20% protein diet (16% gluten + 4% casein) and an experimental group (E) on a 5% protein diet (4% gluten + 1% casein). After isolation, lobules were preincubated 10 min with 10 muCi [3H]-leucine, washed, then incubate within Krebs Ringer bicarbonate Hepes. Basal secretion, then stimulated secretion (50 pM of cholecystokinin (CCK] of radioactive and non-radioactive protein and amylase outputs were measured. During basal secretion, in (E) group, lobules secreted more proteins than (C) one, the same outputs of amylase and radioactive protein were observed in both groups. The stimulated secretion by CCK increased the outputs of non-radioactive protein and amylase of lobules (T) (2-3 fold), but was without effect on lobule (E) outputs. Therefore, a low-protein diet involved a decrease of CCK sensibility on acinar cells, this fact might be mediated by a decreasing number and/or affinity of their CCK receptors.     

Hypocholesterolemic mechanism of Chlorella: Chlorella and its indigestible fraction enhance hepatic cholesterol catabolism through up-regulation of cholesterol 7alpha-hydroxylase in rats

Chlorella powder (CP) has a hypocholesterolemic effect and high bile acid-binding capacity; however, its effects on hepatic cholesterol metabolism are still unclear. In the present study, male Wistar rats were divided into four groups and fed a high sucrose + 10% lard diet (H), an H + 10% CP diet (H+CP), an H + 0.5% cholesterol + 0.25% sodium cholate diet (C), or a C + 10% CP diet (C+CP) for 2 weeks. CP decreased serum and liver cholesterol levels significantly in rats fed C-based diets, but did not affect these parameters in rats fed H-based diets. CP increased the hepatic mRNA level and activity of cholesterol 7alpha-hydroxylase (CYP7A1). CP increased hepatic HMG-CoA reductase (HMGR) activity in the rats fed H-based diets, but not in rats fed C-based diets. CP did not affect hepatic mRNA levels of sterol 27-hydroxylase, HMGR, low-density lipoprotein (LDL) receptor, scavenger receptor class B1, ATP-binding cassette (ABC) A1, ABCG5, or ABCB11. Furthermore, the effect of a 3.08% Chlorella indigestible fraction (CIF, corresponding to 10% CP) on hepatic cholesterol metabolism was determined using the same animal models. CIF also decreased serum and liver cholesterol levels significantly in rats fed C-based diets. CIF increased hepatic CYP7A1 mRNA levels. These results suggest that the hypocholesterolemic effect of CP involves enhancement of cholesterol catabolism through up-regulation of hepatic CYP7A1 expression and that CIF contributes to the hypocholesterolemic effect.     

Oral toxicity of abamectin, boric acid, fipronil, and hydramethylnon to laboratory colonies of Argentine ants (Hymenoptera: Formicidae)

Comprehensive laboratory baiting studies with the 4 insecticides abamectin, boric acid, fipronil, and hydramethylnon were conducted against Argentine ant, Linepithema humile (Mayr). Serial dilutions of each insecticide prepared in a 25% sucrose solution were provided for 24 h or 14 d to groups of workers and queens. Sucrose-water baits containing 1 x 10(-5)% fipronil and 0.1% hydramethylnon provided complete mortality of L. humile workers baited for 24 h. Baits containing 1 x 10(-4) and 1 x 10(-5)% fipronil provided 100% kill of queens. In the continuous baiting, 0.5% boric acid, 1 x 10(-6)% fipronil, and 0.025% hydramethylnon provided 100% mortality of workers. The queens and workers provided baits containing 1 x 10(-5)% fipronil and 0.5% boric acid all died within 14 d. Low concentrations of fipronil and boric acid in sucrose may be promising candidates for Argentine ant control.     

Delayed toxicity as a critical factor in the efficacy of aqueous baits for controlling Argentine ants (Hymenoptera: Formicidae)

Boric acid, imidacloprid, and thiamethoxam in sucrose aqueous baits had different delayed toxicities to worker Argentine ants, Linepithema humile (Mayr). The concentrations required to produce an LT50 (time required to produce 50% mortality) within 1-4 d were 3.63-0.55% boric acid, 9.2 x 10(-3) to 7.1 x 10(-4)% imidacloprid, and 3 x 10(-4) to 2 x 10(-5)% thiamethoxam. The three toxicants were not repellent. Other laboratory trials showed that 1% boric acid, 5 x 10(-4) to 5 x 10(-3)% imidacloprid, and 1 x 10(-5) to 1 x 10(-3)% thiamethoxam had delayed toxic effects, whereas 0.5% boric acid and < 5 x 10(-3)% imidacloprid did not. Baits that provided an LT50 between days 1 and 4 were considered to have delayed toxic effects. The utility of aqueous sucrose baits and toxicants soluble in such systems and the negative impact of fast-acting toxicants on trail following, recruitment, trophallaxis, and control of Argentine ants are discussed.     

Relationship between plasma zinc, angiotensin-converting enzyme, alkaline phosphatase and onset of symptoms of zinc deficiency in the rat

Recent evidence suggests that changes in plasma zinc concentration may play a central role in the development of early lesions of zinc deficiency. The aim of the following work was to better understand events occurring in plasma during the onset of zinc deficiency, and to investigate biochemical mechanisms by which plasma zinc may exert its effects. Fifty male weanling rats of 90 g weight were allocated to five treatment groups of ten rats each. Treatments were: 1, zinc deficient, mixed diet (1-2 mg Zn per kg): 2, zinc deficient, self-select diet; 3, zinc repleted; 4, control, pair fed; 5, control, ad libitum fed. With the exception of treatment 1, which consisted of a 25% casein diet, all rats were offered protein as a separate component of the diet. Control rats received zinc in the drinking water (100 mg l-1). The sequence of events following initiation of zinc deficiency were: reduced plasma zinc concentration (2 days), reduced plasma angiotensin-converting enzyme and alkaline phosphatase activities (3-4 days), reduced feed intake and growth (5-6 days) and reduced percentage protein intake (12 days). Plasma zinc concentration in the deficient rats was inversely correlated with the growth rate of the rat over the previous 24 h. Zinc repletion resulted in marked overshoot in plasma zinc concentration (300%) and converting-enzyme activity (150%) within 24 h, but a return to normal within 72 h. Alkaline phosphatase activity responded likewise, albeit more slowly. Protein self selection had no effect on the manifestations of zinc deficiency, although reduced protein intake was associated with lower plasma zinc concentration. The results provide evidence of a role for plasma zinc in the development of early clinical signs of zinc deficiency, possibly acting biochemically through reduced activity of zinc-dependent peptidases such as angiotensin-converting enzyme.