90-day Feeding Study In Rats Research Articles

A 90-day rodent feeding study with grain for genetically modified maize L4 conferring insect resistance and glyphosate tolerance.

A 90-day rat feeding study was performed to conduct a safety assessment on L4, a multi-gene genetically modified maize, conferring "Bt" insect resistance and glyphosate tolerance. A total of 140 Wistar rats were assigned to seven groups, 10 animals/group/sex, which comprised three genetically modified groups fed diets containing different concentrations of L4, three corresponding non-genetically modified groups fed diets containing different concentrations of zheng58 (parent plants), and a basal diet group fed the standard basal diet for 13 weeks. The fed diets contained L4 and Zheng58 at w/w% percentages of 12.5%, 25.0%, and 50% of the total. Animals were evaluated on some research parameters, including general behaviour, body weight/gain, feed consumption/efficiency, ophthalmology, clinical pathology, organ weights, and histopathology. Throughout the feeding trial, all animals were in good condition. No mortality and no biologically relevant effects or toxicologically significant alterations were observed in the total research parameters of the rats in the genetically modified groups compared with those in the basal diet group or their corresponding non-genetically modified groups. No adverse effects were observed in any of the animals. The results indicated that L4 is as safe and wholesome as conventional, non-genetically modified control maize.

Repercussions of politicized regulation exemplified by compulsory new TC1507-maize 90-day rat feeding study

Politicized and prescriptive regulation of genetically modified (GM) crops has unintended adverse effects, including misdirected resources and reduced benefits. In the case of animal testing, this suboptimal use of resources includes the needless sacrifice of animals. Whole-food animal feeding studies are generally of negligible value in the risk assessment of GM crops, a position that was affirmed by the European Food Safety Authority (EFSA). Contrary to EFSA’s 2011 position, in 2013, the European Commission directed that 90-day rat studies be conducted for new GM events. As no EFSA guidance was available for hypothesis-free 90-day rat feeding studies, EFSA interpreted this as a mandate to develop a prescriptive study design. Recently, EFSA has retroactively required 90-day rat studies be completed under new study guidelines for previously approved component single events as part of the approval of breeding stacks. Having been unable to secure a derogation (exemption) from EFSA, a new compulsory 90-day rat study was conducted with TC1507 maize to support a breeding-stack submission. As previously shown, TC1507 maize does not adversely affect rats. This politically driven additional animal testing is risk disproportionate, at odds with European and international standards for animal welfare, and provides no scientific value to the safety assessment for GM breeding stacks.

Risk Assessment of the Fungicide Luna Privilege with the Active Substance Fluopyram

Luna Privilege is a new fungicide for use in apples, pears, outdoor and indoor strawberries, outdoor and indoor lettuces, peas, beans and indoor tomatoes, and contains the new active substance fluopyram.
 VKM was requested by the Norwegian Food Safety Authority to consider the possible health risk for operators related to the properties of Luna Privilege and fluopyram; in particular to evaluate the potential for bioaccumulation, reproductive and neurotoxic effects, and discuss possible mechanisms involved in liver and thyroid tumor formation observed in rats, and the establishment of NOAELs and reference values.
 VKM was also asked to evaluate the fate and behaviour of fluopyram in the environment, and the ecotoxicological effects and risks related to its use, in particular the potential for groundwater contamination, safety margins and possible effects on birds and aquatic organisms.
 The assessment was finalized in a meeting on December 13. 2013 by VKM’s Panel on Plant Protection Products.
 VKM’s conclusions are as follows:
 Health:
 It is the opinion of VKM that:
 
 The active ingredient fluopyram has low potential for bioaccumulation, and the data do not suggest a sex-specific excretion.
 
 
 
 An in vivo Comet Assay in rat liver could help to further elucidate the genotoxic potential of fluopyram.
 
 
 
 It can not be excluded that the reported incidence of “gall bladder absent” is treatment related.
 
 
 
 NOAEL for the 90-day feeding study in rats should be set to 3.06 mg/kg bw/day, resulting in an AOEL of 0.03 mg/kg bw/day.
 
 
 
 The “dumb-bell or incomplete ossification and/or bipartite/normal cartilage” should be considered as a malformation and regarded as treatment related.
 
 
 
 The time points used for neurotoxic measurements are not optimal to detect neurotoxic effects from acute exposure, since the time window between the first and second measurements is too long.
 
 
 
 The studies where effects of fluopyram and phenobarbital are compared can not be used to exclude human relevance of the tumor-inducing effect of fluopyram in the liver of female rats.
 
 
 
 The results from the mechanistic studies are insufficient to support the proposed mode of action for the induction of thyroid follicular cell tumors in male mice, and thus the induction of thyroid tumors in male mice could be relevant for humans.
 
 VKM proposes:
 
 
 NOAEL of 1.2 mg/kg bw/day based on a 2 year feeding study in rats.
 
 
 
 ADI: 0.012 mg/kg bw/day
 
 
 
 AOEL: 0.03 mg/kg bw/day
 
 
 
 ARfD: 0.25 mg/kg bw/day
 
 
 Risk calculations for field use of Luna Privilege show minimal risk if personal protective equipment is used. The AOEL of fluopyram for greenhouse use is not exceeded, even without protective equipment. Re-entry and bystander exposure is calculated to be well below the AOEL.
 Environment:
 It is the opinion of VKM that:
 
 Worst case degradation rates from laboratory studies should preferably be used to calculate PECsoil values for fluopyram.
 Both fluopyram and fluopyram-7-hydroxy have a high potential for groundwater contamination.
 
 
 
 The efficacy of buffer zones needs to be considered on a case-by-case basis, and further validation of values for efficacy from the model simulation is necessary.
 
 
 
 It is further the opinion of VKM that all the refinements used in the risk assessment for birds are relevant. Since the TER values estimated for all crops except for orchards are below the trigger following refinements, it is the view of VKM that the data indicate medium risk for strawberries and pulses, and high risk for lettuce in open field.
 
 
 
 The use of LC50 values for fluopyram in the TER calculations with a TER trigger value of 100 is overly conservative, and a reduction of the acute trigger for both invertebrates and fish from 100 to 10 for such calculations are suggested.
 
 
 
 The trigger for acute toxicity is not exceeded for any of the crops. For chronic toxicity, VKM concludes that there is a moderate risk for effects on fish when Luna Privilege is applied to beans/strawberries without the use of a vegetated mitigation buffer-strip.

A 90-Day Safety Study of Meat from MSTN and FGF5 Double-Knockout Sheep in Wistar Rats.

MSTN and FGF5 gene knockout sheep generated by the CRISPR/Cas9 system exhibit the ‘double-muscle’ phenotype, and increased density and length of hairs, providing valuable new breeding material. In a previous study, we obtained MSTN and FGF5 double-knockout sheep of significant breeding value. In this study, we carried out a 90-day feeding study in Wistar rats to assess the safety of genome-edited mutton. Seven rat groups with 10 females and 10 males per group were fed different concentrations (3.75%, 7.5%, and 15%) of double-knockout mutton or wild-type mutton in a conventional commercial diet for 90 days. At the end of the feeding, routine urine and blood tests and measurements of blood biochemical indicators were performed. Furthermore, the major organs of each group of rats were weighed and examined histopathologically. Although there were significant differences among the groups in some parameters, all values were within the normal ranges. Therefore, the 90-day rat feeding study showed that the meat from MSTN and FGF5 double-knockout sheep did not have any long-term adverse effects on rat health. This study also provides valuable reference information for assessing the safety of meat from animals with knockout of multiple genes.

Safety assessment of phytase transgenic maize 11TPY001 by 90-day feeding study in rats

11TPY001 is a transgenic maize that expresses the Aspergillus niger phyA2 gene which could significantly improve phosphorus bioavailability in monogastric animals. The present study was conducted to investigate the potential health effects of phytase transgenic maize 11TPY001 through a 90-day subchronic rodent feeding study. Maize grains from 11TPY001 or its parental counterpart maize OSL963 were incorporated into rodent diets at 12.5%, 25% and 50% concentrations by mass and administered to Sprague-Dawley rats (n = 10/sex/group) for 90 days. An additional control group of rats (n = 10/sex/group) were fed with common maize Zhengdan958 diets at 50% by mass. All formulated diets were nutritionally balanced. Body weights, food intake, hematology, serum chemistry, absolute and relative organ weights were measured, and gross as well as microscopic pathology were examined. Compared with rats fed OSL963 maize and the common maize diet groups, no adverse diet-related differences were observed in rats fed 11TPY001 maize diets with respect to clinical signs of toxicity, body weight/gain, food consumption/efficiency, hematology, clinical chemistry, organ weights, and gross and microscopic pathology. Under the conditions of this study, the results indicated that 11TPY001 did not cause any treatment related adverse effects in rats compared with its non-transgenic parental maize OSL963.

Safety evaluation of BPL9K-4 rice in a subchronic rodent feeding study

In the present study, a new genetically modified rice producing phytase-lactoferricin fusion protein, BPL9K-4, was evaluated for safety in a 90-day rat feeding study. Rats were fed rodent diets formulated with BPL9K-4 rice, and were compared with rats fed diets formulated with its corresponding non-transgenic parental rice 9 K, commercially available non-transgenic rice Weiyou64, and a basal diet. BPL9K-4 and 9 K rice were formulated into diets at concentrations of 15%, 30% and 60%, and Weiyou64 common rice was added to diets at concentration of 60%. AIN93G diet was set as a basal-diet control. Diets of all groups were fed to rats (10/sex/group) for 90 days. Compared with rats in the 9 K, Weiyou64 and the basal-diet group, rats fed the BPL9K-4 diet did not show any treatment-related adverse effects on mortality, body weights, feed consumption, clinical chemistry, hematology, organ weights and gross and microscopic pathology. Under the conditions of this study, the genetically modified BPL9K-4 diets did not cause any toxicologically significant effects in rats following 90 days of dietary administration as compared with rats fed diets with the corresponding non-transgenic control diet and the basal-diet group. The results indicated that BPL9K-4 rice is as safe as its conventional comparators.

Equivalence limit scaled differences for untargeted safety assessments: Comparative analyses to guard against unintended effects on the environment or human health of genetically modified maize

Safety assessments guard against unintended effects for human health and the environment. When new products are compared with accepted reference products by broad arrays of measurements, statistical analyses are usually summarised by significance tests or confidence intervals per endpoint. The traditional approach is to test for statistical significance of differences. However, absence or presence of significant differences is not a statement about safety. Equivalence limits are essential for safety assessment. We propose graphs to present the results of equivalence tests over the array of endpoints. It is argued that plots of the equivalence limit scaled difference (ELSD) are preferable over plots of the standardised effect size (SES) used previously for similar assessments. The ELSD method can be used either with externally specified equivalence limits or with equivalence limits estimated from (historical) data. The method is illustrated with two examples: first, environmental safety of MON810 Bt maize was assessed using field trial count data of arthropods; second, human safety of herbicide tolerant NK603 maize was assessed using haematological, biochemical and organ weight data from a 90-day rat feeding study. All assessed endpoints were classified in EFSA equivalence categories I or II, implying full equivalence or equivalence more likely than not.

Subchronic toxicity study in rats evaluating genetically modified DAS-81419-2 soybean

A 90-day feeding study in rats was conducted to evaluate the subchronic oral toxicity of genetically modified (GM) DAS-81419-2 soybean. Wistar rats were fed with diets containing toasted soybean meal produced from DAS-81419-2 soybean grain that expresses the Cry1F, Cry1Ac, and Pat proteins or containing conventional soybean at doses of 30.0%, 15.0%, 7.5%, or 0% (control group) for 90 consecutive days. The general behavior, body weight and food consumption were observed. At the middle and end of the experiment, blood, serum, and urine samples were collected for biochemical assays. At the conclusion of the study, the internal organs were weighed and histopathological examination was completed. The rats exhibited free movement and shiny coats without any abnormal symptoms or abnormal secretions in their noses, eyes, or mouths. There were no adverse effects on body weight in GM soybean groups and conventional soybean groups. No biological differences in hematological, biochemical, or urine indices were observed. No significant differences in relative organ weights were detected between the experimental groups and the control group. No histopathological changes were observed. Under the conditions of this study, DAS-81419-2 soybean did not cause any treatment-related effects in Wistar rats following 90 days of dietary administration.

Evaluation of 30% DAS-444Ø6-6 soybean meal in a subchronic rat toxicity study

Event DAS-444Ø6-6 soybean is genetically modified (GM) to provide tolerance to 2,4-diclorophenoxyacetic acid (2,4-D), glyphosate, and glufosinate herbicides through expression of the AAD-12, 2mEPSPS, and PAT proteins, respectively. DAS-444Ø6-6 soybeans were evaluated for safety in subchronic rat feeding studies. The results from two previous subchronic rat feeding studies evaluating diets formulated with 20% inclusion of DAS-444Ø6-6 soybean meal (the latter also containing DAS-444Ø6-6 derived hulls and oil) did not show any treatment-related adverse effects. In 2017, to comply with recent guidance from EFSA, a third 90-day rat feeding study was conducted with Sprague-Dawley rats (16/sex/group) with diets formulated either with 15% or 30% w/w of toasted DAS-444Ø6-6 soybean meal. DAS-444Ø6-6 soybean hulls and oil were also added to the transgenic test diets at 1% or 2% w/w and 1.35% or 2.7%, respectively, for the low- and high-dose groups. No toxicologically significant effects were observed under the conditions of this study.

Safety assessment of xylan by a 90-day feeding study in rats

Xylans are present naturally in various plants and have important uses in nutrition, food, novel material and biotechnology; however, to date, data regarding their systemic toxicity and safety evaluation is still limited. This study investigated the potential toxicity of xylan from sugarcane bagasse by a subchronic toxicity study in rats. A total of 80 male and female rats were fed with diets containing 10%, 5%, 2.5% and 0% (control) xylan for 90 days. A toxicological assessment was performed including mortality, body and organ weights, food consumption, blood biochemistry, hematology, urinalysis, gross necropsy and histopathological examinations. There were no signs of toxicity and treatment-related changes in rats treated with xylan. The no-observed-adverse-effect levels (NOAEL) of xylan were 9.0 g kg−1 bw for males and 10.6 g kg−1 bw for females of rats under this experimental condition, respectively.

A 90-Day Feeding Study in Rats to Assess the Safety of Genetically Engineered Pork.

Our laboratory recently produced genetically engineered (GE) Meishan pigs containing a ZFN-edited myostatin loss-of-function mutant. These GE pigs develop and grow as normal as wild type pigs but produce pork with greater lean yield and lower fat mass. To assess any potential subchronic toxicity risks of this GE pork, a 90-day feeding study was conducted in Sprague-Dawley rats. Rats were randomly divided into five groups, and fed for 90 days with basic diet and basic diets formulated with low dose and high dose pork prepared from wild type pigs and GE pigs, respectively. Animal behaviors and clinical signs were monitored twice daily, and body weight and food consumption were measured and recorded weekly. At days 45 and 90, blood tests (lipid panel, electrolytes, parameters related to liver and kidney functions, and complete blood counts) were performed. Additionally, gross pathology and histopathological analyses were performed for major organs in each group. Data analysis shows that there were no significant differences in growth rate, food consumption, and blood test parameters between rat groups fed with GE pork and wild type pork. Although differences in some liver function parameters (such as aspartate aminotransferase, total proteins, albumin, and alkaline phosphatase) and white blood cell counts (such as lymphocyte percentage and monocyte percentage) were observed between rats fed with high dose GE pork and basic diet, all test results in rats fed with GE pork are in the normal range. Additionally, there are no apparent lesions noted in all organs isolated from rats in all five feeding groups on days 45 and 90. Overall, our results clearly indicate that food consumption of GE pork produced by ZFN-edited myostatin loss-of-function mutant pigs did not have any long-term adverse effects on the health status in rats.

A 90-day toxicology study of meat from genetically modified sheep overexpressing TLR4 in Sprague-Dawley rats.

Genetic modification offers alternative strategies to traditional animal breeding. However, the food safety of genetically modified (GM) animals has attracted increasing levels of concern. In this study, we produced GM sheep overexpressing TLR4, and the transgene-positive offsprings (F1) were confirmed using the polymerase chain reaction (PCR) and Southern blot. The expression of TLR4 was 2.5-fold compared with that of the wild-type (WT) sheep samples. During the 90-day safety study, Sprague-Dawley rats were fed with three different dietary concentrations (3.75%, 7.5%, and 15% wt/wt) of GM sheep meat, WT sheep meat or a commercial diet (CD). Blood samples from the rats were collected and analyzed for hematological and biochemical parameters, and then compared with hematological and biochemical reference ranges. Despite a few significant differences among the three groups in some parameters, all other values remained within the normal reference intervals and thus were not considered to be affected by the treatment. No adverse diet-related differences in body weights or relative organ weights were observed. Furthermore, no differences were observed in the gross necropsy findings or microscopic pathology of the rats whose diets contained the GM sheep meat compared with rats whose diets contained the WT sheep meat. Therefore, the present 90-day rat feeding study suggested that the meat of GM sheep overexpressing TLR4 had no adverse effect on Sprague-Dawley rats in comparison with WT sheep meat. These results provide valuable information regarding the safety assessment of meat derived from GM animals.

Safety assessment of the fermented Phylloporia ribis (Lonicera japonica Thunb.) mycelia by oral acute toxicity study in mice and 90-day feeding study in rats

Phylloporia ribis is an edible fungus in China. Its fermented mycelia have been approved by the National Health and Family Planning Commission (NHFPC) of PR China for use as a novel food material, but little information on its safety is available. The present research was the first to evaluate acute and subchronic toxicity in experimental animals of fermented Phylloporia ribis mycelia (FPM) following standard procedures. In acute toxicity study, FPM was orally administered to male and female mice twice a day at single dose of 10g/kg bw. The Maximum Tolerated Dose (MTD) of FPM for mice of both sexes was over 10g/kg bw. No death and abnormal behaviors occurred during 14days study except for an increased locomotor activity in three animals. In 90-day feeding study, male and female Sprague–Dawley rats were fed diets containing 10.0%, 5.0%, 2.5%, 1.25% and 0% (control) FPM for 90days. The treatment caused no effects on mortality, gross pathology, histology, hematology, and blood chemistry, no dose-dependent changes in food consumption, but caused effect on body weight gain compared with control group. The No Observed Adverse-Effect Level (NOAEL) of FPM was greater than 8.7g/kg bw/day in both sexes of rats.

Calcium lignosulphonate: Re-evaluation of relevant endpoints to re-confirm validity and NOAEL of a 90-day feeding study in rats

A 90-day feeding study in Han/Wistar rats with calcium lignosulphonate was evaluated by the EFSA. The study was considered to be inadequate due to potentially impaired health status of the animals based upon a high incidence of minimal lymphoid hyperplasia in mesenteric/mandibular lymph nodes and Peyer’s patches, and minimal lymphoid cell infiltration in the liver in all animals. The EFSA Panel further disagreed with the conclusion that the treatment-related observation of foamy histiocytosis in mesenteric lymph nodes was non-adverse and asked whether this observation would progress to something more adverse over time. A PWG was convened to assess the sections of lymph nodes, Peyer’s patches and liver. In addition, all lymphoid tissues were re-examined. The clinical pathology and animal colony health screening data were re-evaluated. The question whether the foamy histiocytosis could progress to an adverse finding with increasing exposure duration was addressed by read-across. In conclusion, the animals on the 90-day feeding study were in good health, the study was adequate for safety evaluation, and the foamy histiocytes in the mesenteric lymph nodes were not considered adverse, but rather an adaptive response that was considered unlikely to progress to an adverse condition with time. The NOAEL was re-affirmed to be 2000mg/kgbw/d.

Safety assessment of meat from transgenic cattle by 90-day feeding study in rats

The study was carried out to evaluate the subchronic toxicity of meat derived from human lactoferrin gene-modified cattle in male and female Wistar rats. Rats were fed 5% or 10% transgenic meat diet, 5% or 10% conventional meat diet, or AIN93G diet for 90 days. During the study, body weight and food consumption were weighed weekly and clinical observations were conducted daily. At the end of the study, urinary examination, hematology and blood biochemistry examination, macroscopic and microscopic examinations were performed. There were no biologically significant differences in these factors between the rat groups fed transgenic meat diet and conventional meat diet. Therefore, the present 90-day rodent feeding study suggests that meat derived from the transgenic cattle is equivalent to meat from conventional cattle in use as dietary supplements.

Scientific Opinion on Safety of smoke flavour ‐ Primary Product – AM 01

This opinion concerns the safety of the smoke flavouring Primary Product AM 01. The Panel noted the shortcomings in the provided analytical data for the characterisation. The product has been tested toxicologically in in vitro and in vivo genotoxicity studies and in a 90-day feeding study in rats. A positive result was obtained in one of three in vitro genotoxicity tests, and another test was inconclusive. In vivo, no indication of DNA damage was obtained in a Comet assay of limited validity. In the light of the reduction of WBC in both sexes and a reduction of lung weight in male at the highest dose level of 500 mg/kg bw/day, the Panel concluded that the NOAEL in the 90-day study was 250 mg/kg bw/day. Given the limitations in the data set, the Panel concluded that the genotoxic potential in vivo of the Primary Product AM 01 can not be ruled out. Furthermore, the Panel noted that there were low margins of safety based on the NOAEL in the 90-day study. Therefore, the use of the substance at the intended uses and use levels would be of safety concern.

Safety of smoke flavour Primary Product - Fumokomp

This Opinion concerns the safety of the smoke flavouring Primary Product Fumokomp. The Panel considered the technical and analytical data provided acceptable to characterise the Primary Product and to demonstrate its batch-to-batch variability and stability. The product has been tested in in vitro and in vivo genotoxicity studies and in a 90-day feeding study in rats. While a positive result was obtained in one out of three in vitro genotoxicity tests, two in vivo genotoxicity tests were negative and sufficient to eliminate the concerns over the in vitro genotoxicity. The 90-day study was conducted before the advent of GLP, and only a summary report was available. In addition the identity of the material tested in this study is unknown. Therefore the Panel was not able to confirm the validity of the study and concluded that the toxicological data do not enable the safety of Fumokomp to be established.

Request from the European Commission related to the safeguard clause invoked by Austria on maize lines MON863 according to Article 23 of Directive 2001/18/EC

Request from the European Commission related to the safeguard clause invoked by Austria on maize lines MON863 according to Article 23 of Directive 2001/18/EC

Comparative safety testing of genetically modified foods in a 90-day rat feeding study design allowing the distinction between primary and secondary effects of the new genetic event

This article discusses the wider experiences regarding the usefulness of the 90-day rat feeding study for the testing of whole foods from genetically modified (GM) plant based on data from a recent EU-project [Poulsen, M., Schrøder, M., Wilcks, A., Kroghsbo, S., Lindecrona, R.H., Miller, A., Frenzel, T., Danier, J., Rychlik, M., Shu, Q., Emami, K., Taylor, M., Gatehouse, A., Engel, K.-H., Knudsen, I., 2007a. Safety testing of GM-rice expressing PHA-E lectin using a new animal test design. Food Chem. Toxicol. 45, 364–377; Poulsen, M., Kroghsbo, S., Schrøder, M., Wilcks, A., Jacobsen, H., Miller, A., Frenzel, T., Danier, J., Rychlik, M., Shu, Q., Emami, K., Sudhakar, D., Gatehouse, A., Engel, K.-H., Knudsen, I., 2007b. A 90-day safety in Wistar rats fed genetically modified rice expressing snowdrop lectin Galanthus nivalis (GNA). Food Chem. Toxicol. 45, 350–363; Schrøder, M., Poulsen, M., Wilcks, A., Kroghsbo, S., Miller, A., Frenzel, T., Danier, J., Rychlik, M., Emami, K., Gatehouse, A., Shu, Q., Engel, K.-H., Knudsen, I., 2007. A 90-day safety study of genetically modified rice expressing Cry1Ab protein ( Bacillus thuringiensis toxin) in Wistar rats. Food Chem. Toxicol. 45, 339–349]. The overall objective of the project has been to develop and validate the scientific methodology necessary for assessing the safety of foods from genetically modified plants in accordance with the present EU regulation. The safety assessment in the project is combining the results of the 90-day rat feeding study on the GM food with and without spiking with the pure novel gene product, with the knowledge about the identity of the genetic change, the compositional data of the GM food, the results from in-vitro/ ex-vivo studies as well as the results from the preceding 28-day toxicity study with the novel gene product, before the hazard characterisation is concluded. The results demonstrated the ability of the 90-day rat feeding study to detect the biological/toxicological effects of the new gene product in the GM food. The authors consider on this basis that the 90-day, rodent feeding study with one high dose level and a dietary design based upon compositional data on the GM food and toxicity data on the gene product is sensitive and specific enough to verify the presence/absence of the biological/nutritional/toxicological effects of the novel gene insert and further by the use of spiking able to separate potentially unintended effects of the novel gene product from other unintended effects at the level of intake defined in the test and within the remit of the test. Recommendations for further work necessary in the field are given.

Toxicological and cytogenetic assessment of a Salacia oblonga extract in a rat subchronic study

Salacia oblonga holds potential as a natural method to mitigate the blood glucose response for people with diabetes by inhibiting the activity of intestinal α-glucosidases. As part of a safety evaluation of novel ingredients for use in blood glucose control, the toxicity of a S. oblonga root extract (SOE) was evaluated in a subchronic 90-day feeding study in rats. An in vivo–in vitro rat peripheral blood lymphocyte chromosomal aberrations assay was added at termination of the subchronic rat study to examine cultured lymphocytes for possible chromosomal aberration induction. This was conducted due to a previous weak; although reproducible, positive chromosomal aberrations response in cultured peripheral blood human lymphocytes after acute in vitro treatment with SOE. The present study results indicate that SOE was negative for the induction of chromosomal aberrations in cultured rat peripheral blood lymphocytes after 90 consecutive days of treatment with SOE. The no observable adverse effect level (NOAEL) was determined to be 2500 mg/kg/day following daily subchronic oral gavage administrations to rats.