Compromised Fertility In Free Feeding Of Wildcaught Norway Rats (\u3ci\u3eRattus norvegicus\u3c/i\u3e) With A Liquid Bait Containing 4-Vinylcyclohexene Diepoxide And Triptolide

Wild rat pests in the environment cause crop and property damage and carry disease. Traditional methods of reducing populations of these pests involve poisons that can cause accidental exposures in other animals and humans. Fertility management with nonlethal chemicals would be an improved method of rat pest population control. Two chemicals known to target ovarian function in female rats are 4-vinylcyclohexene diepoxide (VCD) and triptolide. Additionally, triptolide impairs spermatogenesis in males. A liquid bait containing no active ingredients (control), or containing triptolide (0.001%) and VCD (0.109%; active) was prepared to investigate the potential use of these agents for wild rat pest population control. Liquid bait was made available to male (n = 8 control; n = 8 active) and female (n = 8 control; n = 8 active) Sprague Dawley rats (Rattus norvegicus) for oral consumption prior to breeding. Whereas, control bait-treated females produced normal-sized litters (10.0 ± 1.7 pups/litter), treated females delivered no pups. Wild Norway male (n = 20) and female (n = 20) rats (Rattus norvegicus) were trapped, individually housed, and one group given free access to control bait, one group to active bait. Following three cycles of treatment-matched mating pairs, females consuming control bait (control) produced normal litter sizes (9.73 ± 0.73 pups/litter). Females who had consumed active bait (treated) produced no litters on breeding cycles one and two; however, 2 of 10 females produced small litters on the third mating cycle. In a fourth breeding cycle, control females were crossmated with treated males, and treated females were crossmated with control males. In both groups, some dams produced litters, while others did not. The differences in response reflect a heterogeneity in return to cyclicity between females. These results suggest a potential approach to integrated pest management by compromising fertility, and could provide a novel alternative to traditional poisons for reducing populations of wild rat pests

Laboratory Evaluation of the Effectiveness of the Fertility Control Bait ContraPest® on Wild-Captured Black Rats (\u3ci\u3eRattus rattus\u3c/i\u3e)

A non-toxic liquid fertility control bait for rats has recently become commercially available (ContraPest® from SenesTech, Inc.). This product contains two chemicals, both of which impair spermatogenesis in male and reduce ovulations in female rats. We tested the efficacy of this bait in wild-caught adult black rats from the island of Hawai’i in a short-term laboratory trial. A control group (n = 25) was offered placebo bait and the treatment group (n = 25) was offered fertility control bait, both ad libitum, during a 15-day introduction period and during the first of four breeding rounds, for a total of 58 days of exposure. After treatment, all rats were provided placebo bait for the remainder of the study and randomly paired with mates from within their treatment groups for two additional breeding cycles. Treatment and control groups comprised 10 breeding pairs each, with random re-pairings between breeding rounds. The treatment group produced no litters during the first and second breeding rounds, while 70% of the control females produced litters. In the third breeding round, 70 days after stopping treatment, the treatment group produced three litters (six pups) compared to seven litters (24 pups) in the control group. During a fourth and final breeding round, control rats were crossed with treated rats, producing six litters (27 pups) from treated dams and nine litters (40 pups) from control dams, indicating no apparent infertility effect 99 days after cessation of treatment. This study demonstrates that the reproduction rate of wild-caught black rats can be chemically suppressed if provided ad libitum access to the fertility control bait under laboratory conditions

Laboratory Evaluation of the Effectiveness of the Fertility Control Bait ContraPest® on Wild-Captured Black Rats (Rattus rattus)

A non-toxic liquid fertility control bait for rats has recently become commercially available (ContraPest® from SenesTech, Inc.). This product contains two chemicals, both of which impair spermatogenesis in male and reduce ovulations in female rats. We tested the efficacy of this bait in wild-caught adult black rats from the island of Hawai’i in a short-term laboratory trial. A control group (n = 25) was offered placebo bait and the treatment group (n = 25) was offered fertility control bait, both ad libitum, during a 15-day introduction period and during the first of four breeding rounds, for a total of 58 days of exposure. After treatment, all rats were provided placebo bait for the remainder of the study and randomly paired with mates from within their treatment groups for two additional breeding cycles. Treatment and control groups comprised 10 breeding pairs each, with random re-pairings between breeding rounds. The treatment group produced no litters during the first and second breeding rounds, while 70% of the control females produced litters. In the third breeding round, 70 days after stopping treatment, the treatment group produced three litters (six pups) compared to seven litters (24 pups) in the control group. During a fourth and final breeding round, control rats were crossed with treated rats, producing six litters (27 pups) from treated dams and nine litters (40 pups) from control dams, indicating no apparent infertility effect 99 days after cessation of treatment. This study demonstrates that the reproduction rate of wild-caught black rats can be chemically suppressed if provided ad libitum access to the fertility control bait under laboratory conditions

ContraPest®, a New Tool for Rodent Control

Lethal rodenticides and other lethal tools of managing commensal rodent populations long-term are not sustainable due to population rebounds and increasing resistance to rodenticides. The use of integrated pest management (IPM) programs are more prevalent due to consumer desire to decrease rodenticide use and utilize environmentally friendly, humane methods. IPM plans often require multiple tools to control an infestation, such as physical, biological and chemical measures. Here, we propose that rodent population management would benefit from a new tool aimed at targeting the biological source of overabundance: reproduction. SenesTech, Inc. (Flagstaff, AZ USA) has developed ContraPest®, a liquid bait that limits the reproductive capacity of both male and female wild Norway and Roof rats. The two active ingredients, 4-vinylcyclohexene diepoxide (VCD) and triptolide, deplete all stages of follicles in the female and disrupt spermatogenesis in the male. Laboratory and field studies reveal that ContraPest® is palatable and repeatedly consumed by rats even when provided with ad libitum food and water. Studies involving laboratory and wild caught rats have demonstrated a 93 - 100% reduction in litter sizes of rats treated with ContraPest® compared to control rats. ContraPest® was tested on free ranging rat populations in agricultural and urban settings. Rat populations on protein production farms decreased by an average of 46% following 100 days of treatment with ContraPest®. In a complex urban environment, where property boundaries limit access to populations and foraging areas, ContraPest® reduced the seasonal population peak by 67% after 133 days of baiting. These studies, combined with all of our field studies and population reduction models, demonstrate that ContraPest® is a highly effective rodent contraceptive bait in a variety of environments. We strongly believe that adding/implementing fertility management via ContraPest® to an IPM program would enhance long-term rodent population control in rural, urban, and agricultural environments

Growth Kinetics of Extremely Halophilic Archaea (Family Halobacteriaceae) as Revealed by Arrhenius Plots

Members of the family Halobacteriaceae in the domain Archaea are obligate extreme halophiles. They occupy a variety of hypersaline environments, and their cellular biochemistry functions in a nearly saturated salty milieu. Despite extensive study, a detailed analysis of their growth kinetics is missing. To remedy this, Arrhenius plots for 14 type species of the family were generated. These organisms had maximum growth temperatures ranging from 49 to 58°C. Nine of the organisms exhibited a single temperature optimum, while five grew optimally at more than one temperature. Generation times at these optimal temperatures ranged from 1.5 h (Haloterrigena turkmenica) to 3.0 h (Haloarcula vallismortis and Halorubrum saccharovorum). All shared an inflection point at 31 ± 4°C, and the temperature characteristics for 12 of the 14 type species were nearly parallel. The other two species (Natronomonas pharaonis and Natronorubrum bangense) had significantly different temperature characteristics, suggesting that the physiology of these strains is different. In addition, these data show that the type species for the family Halobacteriaceae share similar growth kinetics and are capable of much faster growth at higher temperatures than those previously reported