Bee Diet Research Articles

Dietary quercetin impacts the concentration of pesticides in honey bees

Honey bees are important pollinators and are subject to numerous stressors, such as changing floral resources, parasites, and agrochemical exposure. Pesticide exposure has been linked to the decline in the global honey bee population. We have limited knowledge of the metabolic pathways and synergistic effects of xenobiotics in bees. Quercetin is one of the most abundant phytochemicals in plants and is therefore abundant in the honey bee diet. Quercetin can upregulate the detoxification system in honey bees; however, it is still unknown to what extent quercetin ingestion can reduce the content of absorbed pesticides. In this study, we investigated the effect of dietary quercetin on the contents of three pesticides in honey bees: imidacloprid (insecticide), tebuconazole (fungicide), and tau-fluvalinate (insecticide and acaricide). Bees were divided into two main groups and fed either quercetin-sucrose paste or only sucrose for 72 h. Thereafter, they were orally exposed to ∼10 ng/bee imidacloprid or contact-exposed to ∼0.9 μg/bee tau-fluvalinate or ∼5.2 μg/bee tebuconazole. After 1 h of oral exposure or 24 h of contact exposure, the bees were anaesthetised with CO2, sacrificed by freezing, and extracted with a validated QuEChERS method. Subsequently, the concentrations of the three pesticides and quercetin in the bees were determined with a triple quadrupole tandem mass spectrometer coupled to an HPLC system. No significant effect on the concentration of tebuconazole or tau-fluvalinate was observed in bees fed quercetin. Intake of quercetin led to a reduction in the concentration of imidacloprid in honey bees. Quercetin-rich plants may be exploited in future beekeeping.

Protective Role of Royal Jelly and Honey against Cisplatin Induced Sperm Function Parameters in Male Rats

Background: Cisplatin is one of the cytotoxic agents in the treatment of cancer and has side effects on sperm function. Objective: This study aims to investigate the ameliorative role of dietary bee honey and royal jelly against cisplatin-induced alterations in sperm function parameters in male wistar albino rat. Methods: Male wistar albino rats of same age and weight were randomly divided into four groups; G, I: control group which was given 0.9% saline, G: II: cisplatin (7 mg/kg/d) was injected intraperitoneally for 15 d, G, III bee honey with royal jelly (500 mg/kg/d of honey and 100 mg/kg/d of royal jelly) fed orally daily for 15 d, G, IV: cisplatin (7 mg/kg/d) was injected intraperitoneally and honey (500 mg/kg/d) and royal Jelly (100 mg/kg/d) fed orally daily for 15 d. The sperm function parameters like sperm count, sperm viability, sperm motility, weight of epididymis and testis were measured by using a hemocytometer under the microscope at 100X magnification. Results: Cisplatin treated rats revealed a significant decrease in sperm count, sperm viability, sperm motility, weight of epididymis and testis as compared to control group. Royal jelly and honey treated group of rats revealed a significant increase in all sperm function parameters compared to control group. Dietary bee honey with royal jelly along with cisplatin-treated rats revealed significant increase as compared to animals treated with cisplatin (G, II). Conclusion: Bee honey and royal jelly could be used as dietary preventive natural products against cisplatin induced sperm function parameters alterations during the treatment of cancer.

The effect of bee pollen on bone biomechanical strength and trabecular bone histomorphometry in tibia of young Japanese quail (Coturnix japonica).

It has been demonstrated in numerous studies that bee pollen supplementation shows numerous positive effects on health. However, its impact on bones is largely unknown. The purpose of this study was to investigate the effect of bee pollen supplementation on the tibia biomechanical properties and bone morphometric measures using Japanese quail as an animal model. The experiment was arranged in a 2x2x2 factorial design, with sex, quail line (meat-type or egg-lying type), and bee pollen inclusion (0 or 10 g/kg of feed) as factors. The quails were one-day-old at the beginning of the experiment, they were euthanized after 42 days. Our study showed for the first time unfavorable effects of bee pollen on bones properties. Bee pollen supplementation negatively affected bone structure, irrespective of quails’ sex or line type. Bone length (P < 0.001), weight (P < 0.01), and mean relative wall thickness (P < 0.01) and mineralization (P < 0.05) were reduced by bee pollen treatment. For female quails, irrespective of line type, the decrease of yield load (P < 0.001), ultimate load (P < 0.01), yield stress (P < 0.001) and ultimate stress (P < 0.05) was noted. Analysis of growth plate in bone metaphysis showed that bee pollen supplementation slowed the process of bone maturation irrespective of sex (P < 0.05). On contrary, dietary bee pollen positively affected bone homeostasis of trabecular bone in bone metaphysis as bone mineral density increased in experimental groups (P < 0.05). In males, this was the result of the increase of trabecular thickness (P < 0.01), in females due to the reduction of trabecular space (P < 0.001). In conclusion, our results demonstrate that bee pollen (1.0%, 10 g/kg of feed) supplementation caused significant negative effects on the mechanical endurance of the tibia of quails, while showed beneficial effects on trabecular bone histomorphometry.

Novel Insights into Dietary Phytosterol Utilization and Its Fate in Honey Bees (Apis mellifera L.).

Poor nutrition is an important factor in global bee population declines. A significant gap in knowledge persists regarding the role of various nutrients (especially micronutrients) in honey bees. Sterols are essential micronutrients in insect diets and play a physiologically vital role as precursors of important molting hormones and building blocks of cellular membranes. Sterol requirements and metabolism in honey bees are poorly understood. Among all pollen sterols, 24-methylenecholesterol is considered the key phytosterol required by honey bees. Nurse bees assimilate this sterol from dietary sources and store it in their tissues as endogenous sterol, to be transferred to the growing larvae through brood food. This study examined the duration of replacement of such endogenous sterols in honey bees. The dietary 13C-labeled isotopomer of 24-methylenecholesterol added to artificial bee diet showed differential, progressive in vivo assimilation across various honey bee tissues. Significantly higher survival, diet consumption, head protein content and abdominal lipid content were observed in the dietary sterol-supplemented group than in the control group. These findings provide novel insights into phytosterol utilization and temporal pattern of endogenous 24-methylenecholesterol replacement in honey bees.

Enhancement of Apis mellifera L. Hypopharyngeal Gland using Hyphaene thebaica Ethanolic Extract as Supplement.

Hypopharyngeal gland (HPG) of Apis mellifera L. honey bee workers secrete the main proteinaceous substances, the royal jelly which acts a vital role in brood care by young workers and thus colony growth. Many factors may affect the development and function of the hypopharyngeal gland and consequently their role within the beehive. Hyphaene thebaica fruit powder (500 g) was soaked in one litter of 70% ethanol for 3 days at room temperature, then filtered and concentrated to dryness with a rotary evaporator. Bioactive compounds and biological activity of doum ethanolic extract were characterized to measure the extent of safety. Samples of workers bee feeding with the extract concentrations (0.5 and 1%) at 6, 10 and 14 days were examined for head weight, body weight, soluble protein content, DNA fragmentation and hypopharyngeal glands histology, the data were analyzed using analysis of variance (ANOVA), Tukey's least significant difference. Ethanolic doum extract contains flavonoids (45.62 mg g-1) and phenolic (27.24 mg g-1) compounds, also possess antioxidant (147 μg mL-1), anti-inflammatory (119.8 μg mL-1) and antimicrobial activities. There was an elevation in soluble protein content and no DNA damage in the honey bee worker's genome after fourteen days of feeding. The histological studies exhibited no deformation in the structure of gland acini and an increase in gland size was detected. Ethanolic doum extract in the bee diet has a role in HPG enhancement. Studies on its safety profile and biological activities make it a good choice to attenuate honey bee diseases inside bee colonies.

Impact of dietary bee honey during first weeks of life in dairy lambs on growth and metabolism

Bee honey has beneficial properties that are recognized worldwide, including high nutritional value. The objective of this study was to determine whether a daily dose of honey would improve productive performance as well as energy, protein, and lipid metabolisms in lactating lambs. Bee honey (from Apis mellifera) was offered orally for the first 7 days of the animals’ lives. Twenty Lacaune lambs were used, allocated to two groups: group C, lambs not supplemented with honey, and group T, consisting of lambs fed daily doses of 10 mL of honey. The experimental period lasted 45 days. Body weight measurements and blood sample collections were performed at five time points (days 1, 7, 15, 30, and 45 of life). The lambs that consumed honey showed significantly greater weight gain during the experimental period; there was greater weight gain between days of life 30 and 45. We found significantly higher levels of urea (days 30 and 45) and globulins (day 45). Carbohydrate (glucose), lipid (triglycerides and cholesterol), and protein (total protein and albumin) levels did not differ between treatments. Based on these preliminary results, we conclude that supplementation with honey in the lamb diets may stimulate growth in during lactating phase.

Forage quality and quantity affect red mason bees and honeybees differently in flowers of strawberry varieties

AbstractNectar is a vital source of energy for bees and other pollinators and pollen represents the only source of protein in the diet of bees. Nectar and pollen quality and quantity can therefore affect foraging choices. Strawberry, Fragaria × ananassa (Rosaceae), is a flowering crop that requires insect pollination for the berries to develop optimally. The solitary red mason bee, Osmia bicornis L. (Hymenoptera: Megachilidae), occurs naturally but like the eusocial western honeybee, Apis mellifera mellifera L. (Hymenoptera: Apidae), it is also a commercially reared pollinator used in strawberry production. We hypothesized that strawberry nectar and pollen quality would affect the foraging choice of these two types of bees. In this study nectar and pollen quality is represented by various levels of sugar and protein content, respectively, as well as the number of open strawberry flowers in the experimental field, would affect the foraging choice of these two types of bees. Consistent with previous studies, we found significant and major differences between strawberry varieties in proportions of sucrose in the nectar sugar and in pollen viability – a proxy for pollen protein content. All measured parameters had a significant effect on red mason bee visitation frequency. Contrary to expectations, honeybee foraging behavior was only affected by the number of open flowers and not by any of the quality parameters measured. Our findings indicate that red mason bees were capable of assessing nectar and pollen quality and prioritize accordingly. The pattern observed indicates that individual red mason bees changed foraging focus between strawberry varieties depending on whether nectar or pollen was collected. Our results suggest that targeted breeding of varieties toward high levels of nectar sugar and sucrose concentrations and high pollen protein content may increase pollination success from red mason bees and possibly other solitary bees.

From plant fungi to bee parasites: mycorrhizae and soil nutrients shape floral chemistry and bee pathogens.

Bee populations have experienced declines in recent years, due in part to increased disease incidence. Multiple factors influence bee-pathogen interactions, including nectar and pollen quality and secondary metabolites. However, we lack an understanding of how plant interactions with their environment shape bee diet quality. We examined how plant interactions with the belowground environment alter floral rewards and, in turn, bee-pathogen interactions. Soil-dwelling mycorrhizal fungi are considered plant mutualists, although the outcome of the relationship depends on environmental conditions such as nutrients. In a 2×2 factorial design, we asked whether mycorrhizal fungi and nutrients affect concentrations of nectar and pollen alkaloids (anabasine and nicotine) previously shown to reduce infection by the gut pathogen Crithidia in the native bumble bee Bombus impatiens. To ask how plant interactions affect this common bee pathogen, we fed pollen and nectar from our treatment plants, and from a wildflower pollen control with artificial nectar, to bees infected with Crithidia. Mycorrhizal fungi and fertilizer both influenced flowering phenology and floral chemistry. While we found no anabasine or nicotine in nectar, high fertilizer increased anabasine and nicotine in pollen. Arbuscular mycorrhizal fungi (AMF) decreased nicotine concentrations, but the reduction due to AMF was stronger in high than low-nutrient conditions. AMF and nutrients also had interactive effects on bee pathogens via changes in nectar and pollen. High fertilizer reduced Crithidia cell counts relative to low fertilizer in AMF plants, but increased Crithidia in non-AMF plants. These results did not correspond with effects of fertilizer and AMF on pollen alkaloid concentrations, suggesting that other components of pollen or nectar were affected by treatments and shaped pathogen counts. Our results indicate that soil biotic and abiotic environment can alter bee-pathogen interactions via changes in floral rewards, and underscore the importance of integrative studies to predict disease dynamics and ecological outcomes.

Important Plants for Honey Production in Four Agro Ecological Zones of Uganda

The diet of honey bees consists of protein-rich pollen and sugar-rich nectar collected separately or synchronously from flowers by foraging worker bees (Kajobe, 2006, 2007). These resources are col...

정제 봉독의 급여가 육계의 혈청성상, 항산화능 그리고 간 내 지방산 조성에 미치는 효과

This study was conducted to investigate the effect of dietary bee venom on serum characteristics, antioxidant activity, and hepatic fatty acid composition in broiler chickens. A group of 875 one-day-old feather-sexed male broiler chicks were randomly allocated to five treatments with seven replicates (25 birds/replicate) for three weeks. A corn-soybean meal-based diet was used as the basal diet. Five dietary treatments were compared: 1) basal diet, 2) basal diet containing 10 μg/kg of bee venom powder, 3) basal diet containing 50 μg/kg of bee venom powder, 4) basal diet containing 100 μg/kg of bee venom powder, and 5) basal diet containing 500 μg/kg of bee venom powder. At 21 days, one bird per pen was slaughtered by asphyxiation in CO₂ gas, and blood was collected to measure serum characteristics and antioxidant activity. In addition, the liver was excised to measure the concentration of malondialdehyde and determine fatty acid composition. Increasing dietary bee venom in the diet failed to affect most serum parameters except for triglyceride and non-esterified fatty acids. Dietary bee venom inclusion quadratically increased the concentration of stearic acid (<italic>P</italic>&lt;0.05), but decreased palmitoleic acid, oleic acid, linoleic acid, mono-unsaturated fatty acids, and poly-unsaturated fatty acids. Finally, dietary bee venom tended to lower hepatic malondialdehyde contents quadratically (<italic>P</italic>=0.054). In conclusion, our study revealed that dietary bee venom improved antioxidant capacity and affected fatty acid metabolism in broiler chickens.

Supplementing With Vitamin C the Diet of Honey Bees Parasitized With Varroa destructor: Effect on Carbohydrate Metabolism

The most profound decrease in the number of honey bee (Apis mellifera carnica) colonies is observed after winter. This study evaluates the effect of vitamin C (ascorbic acid, AA) supplementation in wintering colonies of honey bees naturally infested with the parasitic mite Varroa destructor on total carbohydrate content, glycogen, trehalose, glucose and fructose concentrations, and the activity of amylase and disaccharidases in a developing worker brood. The severity of the infestation was lower (1.18&amp;plusmn;0.6 of mites per bee) in bees whose diet were supplemented with vitamin C (group AA) than in the control group (C) (1.32&amp;plusmn;0.56 mites/bee). Glycogen and trehalose levels and the activity of &amp;alpha;-amylase, glucoamylase and trehalase were significantly higher in newly emerged workers from group AA. The results of the study indicate that vitamin C in the diet of honey bees moderately reduces infestation levels and might improve selected indicators of carbohydrate metabolism in infested workers and thus improves the condition of apiaries.

Wild Bee Pollen Diets Reveal Patterns of Seasonal Foraging Resources for Honey Bees

Western honey bees (Apis mellifera) are dominant crop pollinators, and access to summer forage is a critical factor influencing colony health in agricultural landscapes. In many temperate agricultural regions, honey bees forage extensively from non-native plants during the summer, but it is unclear whether the use of these species is due to honey bee preference for these plants or is a result of their relative abundance. The foraging choices made by native bees that have evolved with native plants can reveal the seasonal availability of native plant pollens, and so we quantified the pollen collected by 181 wild bee species native to Michigan. Pollen was also trapped from honey bee colonies during the summer to confirm the peak period of non-native pollen collection in this region. Across the state, the generic richness of native pollens collected by wild bees peaked in May before linearly declining into September. Wild social and solitary bees collected a similar proportion of their pollen from non-native plants from April to July, but during August and September social bees collected a significantly greater proportion from non-natives. At a local scale, honey bees collected the majority of their pollen from non-native plants between 4 July and 21 August, with the same trend seen in both social and solitary bees. Across the region, a significantly greater proportion of the solitary bee species that peak during this time are specialists, most of which collect from native plant species that are little utilised by social bees for pollen, such as Dasiphora, Helianthus, Physalis and Vernonia. Our results suggest that Michigan has relatively few native flowering resources during the height of the summer, and that many of those which flower during this time are used primarily by specialised solitary bee species rather than the social bee community, including honey bees. As a result, non-native plant species with a late summer flowering phenology fill a forage gap and thus can contribute to the diet of both honey bees and generalist wild bees during this time, despite the well-documented negative impacts of these species on native plant communities.

Biphasic concentration-dependent interaction between imidacloprid and dietary phytochemicals in honey bees (Apis mellifera).

BackgroundThe presence of the neonicotinoid imidacloprid in nectar, honey, pollen, beebread and beeswax has been implicated in declines worldwide in the health of the western honey bee Apis mellifera. Certain phytochemicals, including quercetin and p-coumaric acid, are ubiquitous in the honey bee diet and are known to upregulate cytochrome P450 genes encoding enzymes that detoxify insecticides. Thus, the possibility exists that these dietary phytochemicals interact with ingested imidacloprid to ameliorate toxicity by enhancing its detoxification.ApproachQuercetin and p-coumaric acid were incorporated in a phytochemical-free artificial diet individually and together along with imidacloprid at a range of field-realistic concentrations. In acute toxicity bioassays, honey bee 24- and 48- hour imidacloprid LC50 values were determined in the presence of the phytochemicals. Additionally, chronic toxicity bioassays were conducted using varying concentrations of imidacloprid in diets with the phytochemicals to test impacts of phytochemicals on longevity.ResultsIn acute toxicity bioassays, the phytochemicals had no effect on imidacloprid LC50 values. In chronic toxicity longevity bioassays, phytochemicals enhanced honey bee survival at low imidacloprid concentrations (15 and 45 ppb) but had a negative effect at higher concentrations (105 ppb and 135 ppb). p-Coumaric acid alone increased honey bee longevity at concentrations of 15 and 45 ppb imidacloprid (hazard ratio (HR): 0.83 and 0.70, respectively). Quercetin alone and in combination with p-coumaric acid similarly enhanced longevity at 45 ppb imidacloprid (HR:0.81 and HR:0.77, respectively). However, p-coumaric acid in combination with 105 ppb imidacloprid and quercetin in combination with 135 ppb imidacloprid increased honey bee HR by approximately 30% (HR:1.33 and HR:1.30, respectively).ConclusionsThe biphasic concentration-dependent response of honey bees to imidacloprid in the presence of two ubiquitous dietary phytochemicals indicates that there are limits to the protective effects of the natural diet of honey bees against neonicotinoids based on their own inherent toxicity.

AMELIORATIVE ROLE OF BEE HONEY AND ROYAL JELLY AGAINST CISPLATIN INDUCED ALTERATION IN HEMATOLOGICAL PARAMETERS IN MALE WISTER ALBINO RAT

Objective: This study aims to investigate the ameliorative role of dietary bee honey and royal jelly against cisplatin-induced alterations in hematological parameters in male wistar albino rat.Methods: Male wistar albino rats of same age and weight were randomly divided into four groups; G, I: control group which was given 0.9% saline, G: II: cisplatin (7 mg/kg/d) was injected intraperitoneally for 15 d, G, III bee honey with royal jelly (500 mg/kg/d of honey and 100 mg/kg/d of royal jelly) fed orally daily for 15 d, G, IV: cisplatin (7 mg/kg/d) was injected intraperitoneally and honey (500 mg/kg/d) and royal Jelly (100 mg/kg/d) fed orally daily for 15 d. The hematological parameters like total number of white blood cells (WBCs), red blood cells (RBCs), platelets, % of hemoglobin (Hb), and mean values of packed cell volume (PCV), mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC) were measured by using automated hematology system.Results: Cisplatin treated rats revealed a significant decrease in total number of white blood cells (WBCs), red blood cells (R. B. Cs), platelets, percentage of hemoglobin (Hb), and mean values of packed cell volume (PCV), corpuscular volume (MCV) and corpuscular hemoglobin concentration (MCHC) as compared to control group. Royal jelly and honey treated group of rats revealed a significant increase in all blood parameters compared to control group. Dietary bee honey with royal jelly along with cisplatin-treated rats revealed significant increas as compared to animals treated with cisplatin (G, II) and the computed significant valus for the above parameters are 10.00, 2.30, 8,54, 12.00, 35.00, 47.40 and 32,30 respectively.Conclusion: Bee honey and royal jelly could be used as dietary preventive natural products against cisplatin-induced hematological alterations during the treatment of cancer.

Using DNA metabarcoding to investigate honey bee foraging reveals limited flower use despite high floral availability

Understanding which flowers honey bees (Apis mellifera) use for forage can help us to provide suitable plants for healthy honey bee colonies. Accordingly, honey DNA metabarcoding provides a valuable tool for investigating pollen and nectar collection. We investigated early season (April and May) floral choice by honey bees provided with a very high diversity of flowering plants within the National Botanic Garden of Wales. There was a close correspondence between the phenology of flowering and the detection of plants within the honey. Within the study area there were 437 genera of plants in flower during April and May, but only 11% of these were used. Thirty-nine plant taxa were recorded from three hives but only ten at greater than 1%. All three colonies used the same core set of native or near-native plants, typically found in hedgerows and woodlands. The major plants were supplemented with a range of horticultural species, with more variation in plant choice between the honey bee colonies. We conclude that during the spring, honey bees need access to native hedgerows and woodlands to provide major plants for foraging. Gardens provide supplementary flowers that may increase the nutritional diversity of the honey bee diet.

Amino acid profile of broiler chickens meat fed diets supplemented with bee pollen and propolis

The objective of this study was to evaluate the effects of diets supplemented with bee pollen and propolis on the amino acid (AA) profile of chicken meat. A total of 360 one day-old Ross 308 broiler chicks were randomly assigned to three treatments: a basal diet without supplementation as control (C); a basal diet supplemented with bee pollen extract (400 mg kg−1 of feed mixture: E1); and a basal diet supplemented with propolis extract (400 mg kg−1 of feed mixture: E2). Chickens were slaughtered at 42 d of age. After slaughter, the AA profile of breast and thigh samples was determined. The data were analyzed using analysis of variance. The AA profile was not affected by dietary bee pollen supplementation (E1) in breast and thigh muscles (disregarding sex), except for higher concentration of Tyr (p ≤ 0.05) in breast and lower concentration of Pro (p > 0.05) in breast and thigh muscles compared with those in C. However, the AA profile was improved in response to propolis supplementation (E2). In breast muscle (disregarding sex), the highest concentrations of Glu (11.81 g 100 g−1), Gly (3.5 g 100 g−1), and Tyr (4.12 g 100 g−1) were found in the propolis-supplemented group (E2), Glu and Tyr were higher (p ≤ 0.05) in E2 compared with those in C, while Gly was higher (p ≤ 0.05) in E2 compared to E1. Additionally, many other AAs (Asp, Ser, Ala, Tyr, Arg, Thr, Ile, Leu, Phe, and Lys) were observed as the highest (p > 0.05) in breast muscle of broilers fed a diet with propolis extract (E2). In thigh muscle (disregarding sex), higher concentrations (p ≤ 0.05) of Tyr (2.46 g 100 g−1) and His (2.35 g 100 g−1) were found in the propolis-supplemented group (E2) compared with those in C. Many other AAs (Glu, Gly, His, Arg, Thr, Val, Ile, Leu, and Lys) in thigh muscle from propolis-supplemented group (E2) were also higher (p > 0.05) than those in the other groups. After bee pollen (E1) and propolis (E2) supplementation, no differences in amino acid concentrations between males and females, or in breast or thigh muscle were found. In general, breast was demonstrated to contain higher proportions of AAs than thigh muscle. In conclusion, dietary propolis supplementation in amount of 400 mg kg−1 of feed mixture elicited the best AA profile of chicken meat among the dietary treatments and may thus be a promising method to improve meat quality.

Diet characterisation of solitary bees on farmland: dietary specialisation predicts rarity.

Changes in agricultural practice across Europe and North America have been associated with declines in wild bee populations. Bee diet breadth has been associated with sensitivity to agricultural intensification, but much of this analysis has been conducted at the categorical level of generalist or specialist, and it is not clear to what extent the level of generalisation within generalist species is also associated with species persistence. We used pollen load analysis to quantify the pollen diets of wild solitary bees on 19 farms across southern England, UK. A total of 72 species of solitary bees were recorded, but only 31 species were abundant enough to allow for formal diet characterisation. The results broadly conformed to existing literature with the majority of species polylectic and collecting pollen from a wide range of plants. Pollen load analysis consistently identified pollens from more plant species and families from each bee species than direct observation of their foraging behaviour. After rarefaction to standardise pollen load sample sizes, diet breadth was significantly associated with frequency of occurrence, with more generalist bees present on more farms than less generalist bees. Our results show that the majority of bee species present on farmland in reasonable numbers are widely variable in their pollen choices, but that those with the broadest diet were present on the greatest number of farms. Increasing the diversity of plants included in agri-environment schemes may be necessary to provide a wider range of pollen resources in order to support a diverse bee community on farmland.Electronic supplementary materialThe online version of this article (doi:10.1007/s10531-016-1191-x) contains supplementary material, which is available to authorized users.

Toward a new rapid method to assess plant species in a bee pollen diet

Honey bee diet surveys require an accurate knowledge of the pollen supply and a rapid counting method for microscopic analyses. Referring to the literature, we aimed at reducing the number of pollen grains counted in order to decrease the time spent for each sample. For this, we compared counts on whole transects to alternative methods of counting by sub-sampling, using the non-acetolysed palynological method. For each pellet sample, a drop of a homogenized suspension was dried, degreased, and mounted onto a slide dressed with glycerol gelatin. The counting was performed through a digital camera fitted on a microscope. The study was carried out in two phases. Phase 1 was a test of slide homogeneity, carried out on a 10-slide set with one replicate. For each slide, we compared an exhaustive count of each present taxon on a whole transect divided in four quarters. Phase 2 was a search for an alternative counting method. The work was performed over the first six samples with replicates retaining exactly the same transect, but counting only one microscope field in three, then four, and finally one in five. Data analyses were carried out with Chi-square tests on taxa that were present in more than 5% of the sample. Phase 1 showed some cases of heterogeneity in microscope slides, leading to an error hazard when counting in a continuous mode up to a defined grain number. In phase 2, the comparison of alternative countings to full transects verified the linearity of the counting results. Suitable results were given by the reading method “one in three”. We improved the accuracy of this method for the particular case of samples containing large pollen grains, e.g., Zea mays, which are unevenly disseminated on the slide.

The effect of dietary bee pollen intake on growth performance and biochemical indicators of rats

The aim of this study was to analyse the effects of different daily intakes of rapeseed bee pollen on the growth and biochemical blood serum indicators in male and female rats. A total of 40 clinically healthy male and female Wistar rats were randomly divided into four groups. In the control group (C) rats were fed a standard complete diet; in the experimental groups standard diets were supplemented with different doses of bee pollen. Treatment group T1 was given standard diet with the addition of bee pollen at a 0.3% concentration; in group T2 the addition was 0.5%; and in group T3 it was 0.75%. The experimental period lasted for 90 days. A significant effect (P &lt; 0.05) of bee pollen on the body weight gain and feed conversion ratio of female rats was found. Significantly (P &lt; 0.05) higher cholesterol concentration in blood serum of male rats was found in the groups with bee pollen addition (groups T2 and T3) compared to the control group. Lower triglyceride serum content in all female experimental groups (T1 and T3) was observed in comparison to the control. Higher serum cholesterol content in the experimental female rats was detected; significant differences were analysed in groups T1 and T3 compared to the control female group. Rapeseed bee pollen at concentrations of 0.5 and 0.75% positively affected the body weight gain of female rats, however, with higher feed consumption (P &lt; 0.05). Rapeseed bee pollen reduced the triglycerides serum content in female rats and increased the cholesterol serum content in male and female rats (P &lt; 0.05).

The effects of dietary bee pollen on lipid peroxidation and fatty acids composition of Japanese quails (Coturnix coturnix japonica) meat under different stocking densities

ABSTRACTThe objective of this study was to investigate the effects of supplementation of bee pollen (1 g/kg) to the basal diet on lipid peroxidation and the fatty acids composition of Japanese quails under different stocking densities. Hundred and sixty Japanese quails were divided into 3 treatment groups each with four replicates consisting of 8 birds in control group and 16 birds in the other groups. Experimental groups were arranged as Control (160cm2/quail without supplementation), high stocking density (HSD) (80 cm2/quail without supplementation), and POL (80 cm2/quail and 1g/kg bee pollen). Plasma Malondialdehyde level in the HSD group was significantly higher than those of Control and POL groups (P < .01). The catalase activity in blood of Control and POL groups was significantly higher than those of the HSD group(P < .01). In the HSD group the total polyunsaturated fatty acid (PUFA) ratio was lowered in all tissues. Increased PUFA ratios were observed in breast muscle and kidney tissue (P < .001), leg muscle (P < .05) and liver (P < .01) tissue in pollen-supplemented quails compared with the other groups. The n–6 PUFA ratio of breast muscle, kidney tissue (P < .001) and liver tissue (P < .01) was higher in the POL group than the other groups. As a result, the present study suggests that bee pollen supplementation to 1 g/kg diet had potential protective activity on lipid peroxidation and tissue fatty acid composition of quails reared under HSD. In all groups, the bee pollen consumption increased PUFA levels in tissues, especially n-6 PUFA.