Neonicotinoids in the agroecosystem: In-field long-term assessment on honeybee colony strength and microbiome.

Bees can be severely affected by various plant protection products (PPP). Among these, neonicotinoid insecticides are of concern as they have been shown to be responsible for extensive honeybee colonies death when released into the environment. Also, sublethal neonicotinoid doses contaminating single honeybees and their colonies (e.g. through contaminated pollen) are responsible for honeybees physiological alterations with probable implication also on microbiome functionality. Honeybees show symbiotic interactions with specific gut bacteria that can enhance the adult host performances. Among the known mechanisms, the modulation of the immune system, the degradation of recalcitrant secondary plant metabolites, pollen digestion, and hormonal signaling, are the most important functional benefits for the host honeybee. To date, few research efforts have aimed at revealing the impact of PPP on the gut microbial community of managed and wild honeybees. The majority of the existing literature relays on cage or semifield tests of short duration for research investigating neonicotinoids-gut microbiome interactions. This research wanted to unravel the impact of two neonicotinoids (i.e. imidacloprid and thiacloprid) in natural field conditions up to 5 weeks of exposure. A long-term impact of neonicotinoids on gut microbial community of honeybees was observed. The alterations affected several microbial genera and species such as Frischella spp., lactobacilli and bifidobacteria, whose shifting is implicated in intestinal dysbiosis. Long-term impact leading to dysbiosis was detected in case of exposure to imidacloprid, whereas thiacloprid exposure stimulated temporary dysbiosis. Moreover, the microbial diversity was significantly reduced in neonicotinoid-treated groups. Overall, the reported results support a compromised functionality of the gut microbial community, that might reflect a lower efficiency in the ecosystemic functionality of honeybees.

Enrichment of the diet with synthetic and natural sources of provitamin A.

The use of available food rich in provitamin A and retinol as well as fortification of local food are known to result in adequate vitamin A status. In Brazil, several regional foods are known to be good sources of provitamin A such as buriti, several palm oils, mango and others. Improving the consumption of these locally available natural sources of provitamin and vitamin A would cover the needs of the vulnerable population. At the same time fortification of industrialized foods with natural and/or synthetic forms of provitamin A could speed up and fill the gap between requirement and low intake of this vitamin in many parts of the country. This approach has been considered by many as the most effective intervention program to prevent micronutrient deficiencies in developing countries. Our previous studies on the subject have shown that cooking vegetable oil, mainly soybean oil, is a very good alternative vehicle to be fortified and supply vitamin A to the population. Lately we have also enriched the same soybean oil with beta-carotene. Addition of this provitamin A to the oil showed it to be stable when heated at cooking and frying temperatures (retention of 92.4 +/- 6.7% and 65.4 +/- 8.6%, respectively). When rat or human food was prepared with carotene-enriched cooking oil, its bioavailability in experimental animals and absorption in humans were shown to be adequate. An alternative for Brazil, besides adding chemical forms of the vitamin to the cooking oil, would be to mix available carotene-rich palm oil to the soybean oil. There are already regional uses of carotenoid-rich palm oils in the preparation of local dishes in some parts of Brazil and this would facilitate its acceptance by the population. Enrichment of common foods in Brazil, such as soybean oil, with chemical forms of beta-carotene or mixing rich sources of provitamin A can be a good alternative to improve the intake of vitamin A by the Brazilian population.

Absorption, by humans, of beta-carotene from fortified soybean oil added to rice: effect of heat treatment.

OBJECTIVE: This study was carried out to evaluate the absorption of beta-carotene in humans when rice is prepared with refined cooking soybean oil fortified with beta-carotene and to assess the effect of heat treatment on its bioavailability. METHODS: Sixteen healthy adults subjects participated in two experimental trials. Studies were carried out during two experimental periods of 11 days with a 12-day interval between them. Beta carotene was added to the soybean cooking oil and rice was cooked with it or it was added to the rice after cooking. Experimental diets included these two kinds of rice during the first day and fasting blood samples were collected on different days. All of the test diets were low in carotenoids. Plasma carotenoids were measured by HPLC method. beta-carotene absorption was calculated through postabsorptive peak rise in plasma beta-carotene and the total area under the absorption curve was determined by the trapezoidal method for the 11-day period. RESULTS: Absorption of carotene from heated or unheated fortified soybean oil were similar. Peak plasma carotene rise was different in men and women, p < 0.05 (0.66 +/- 0.097 vs. 1.04 +/- 0.117 mumol/l, respectively). Plasma alpha-carotene and retinol showed no variation. CONCLUSIONS: Results demonstrate that beta-carotene added to soybean oil used in the preparation of rice is absorbed, heated or not, and could be a practical source of provitamin A. Developing countries looking for strategies to increase vitamin A intake could use fortification of vegetable oils with synthetic beta-carotene as a simple method.

Effect of heat treatment on the biological value of beta-carotene added to soybean cooking oil in rats.

Vitamin A deficiency is one of the major nutritional problems in the world, most common in developing countries. Food fortification is a recognised approach to supply vitamins and minerals to needed populations. Vegetable cooking oils were previously suggested by us as a carrier for vitamin A fortification. Fortification of cooking oil with beta-carotene could also be a strategy to prevent vitamin A deficiency. The objective of this article is to start studies on the use of cooking soya oil as a vehicle for synthetic carotene, to evaluate its stability to heat treatment, and to test its bioavailability and bioconversion to vitamin A in rats. Batches of carotene-fortified soybean oil were prepared, containing 2, 4 and 8 RE/g of diet. Some of them were heated to test its stability. At 100 degrees C there was no loss of carotene, at higher temperature carotene retention was 65%. The bioavailability and bioconversion of beta-carotene added to soybean oil was measured through feeding nursing rats and their pups method. Weight gain was good and plasma vitamin A increased significantly in all groups. Liver vitamin A values of rats fed diets with fortified soybean oil heated at 100 degrees C was similar to the 4 RE non-heated fortified oil group (0.72 +/- 0.06 and 0.64 +/- 0.08 mumol/g, respectively). Heated at 170 degrees C the liver total vitamin A value was reduced (0.45 +/- 0.04 mumol/g), but kept bioavailable vitamin A equivalent to 2 RE (0.47 +/- 0.09 mumol/g). Bioconversion of beta-carotene to vitamin A was validated by the plasma and liver findings. beta-carotene added to soybean oil showed good stability to heat and its bioconversion to vitamin A was shown in rat assays. beta-carotene mixed well with edible soybean oil and the fortified cooking oil showed potential as a carrier to be used for the prevention of vitamin A deficiency.

Assessment of vitamin A status in chronic obstructive pulmonary disease patients and healthy smokers.

The relation between vitamin A status and the degree of lung airway obstruction was examined in a cross-sectional study of 36 male subjects aged 43-74 y who were assigned to five groups as follows: healthy nonsmokers (n = 7), healthy smokers (n = 7), mild chronic obstructive pulmonary disease (COPD-mild) patients (n = 9), COPD-moderate-severe patients (n = 7), and COPD-moderate-severe patients with exacerbation (+ex; n = 6). Smoking habits, pulmonary function tests, energy-protein status were assessed; serum concentrations of retinyl esters, retinol, retinol binding protein, and transthyretin and relative dose responses were measured. In addition, 12 male smokers aged 45-61 y with mild COPD were randomly assigned to two groups for a longitudinal study: six subjects consumed vitamin A (1000 RE/d; COPD-vitamin A) and six subjects received placebo for 30 d. Lowered serum retinol concentrations were found in the COPD-moderate-severe and COPD-moderate-severe+ex groups. Measurements of vitamin A status in healthy smokers and in COPD-mild patients were not different from those in healthy nonsmokers. The improvement of pulmonary function test results after vitamin A supplementation [mean increase for 1-s forced expiratory volume (FEV1) = 22.9% in the COPD-vitamin A group] may support the assumption of a local (respiratory) vitamin A deficiency in patients with this disease.

Evaluation of rose bengal staining test and rapid dark-adaptation test for the field assessment of vitamin A status of preschool children in Southern Brazil.

The objective of this study was to evaluate two of several methods presently available for assessing vitamin A status of marginally malnourished preschool children of socioeconomically deprived families in Southern Brazil. The rose bengal staining test and rapid dark-adaptation test were evaluated by comparing their results with conventional methods that require estimation of dietary intake of vitamin A equivalents and determination of plasma levels of retinol before and after an oral supplementation of 200 000 IU vitamin A. Results indicate that neither test evaluated is useful by itself. There was no significant correlation between the results of the rose bengal staining test and the plasma levels of retinol. Also, no significant correlation was observed between the rapid dark-adaptation time and the vitamin A status of the preschool children as determined by plasma-retinol levels before and after vitamin A supplementation.