Varroa treatment with bromfenvinphos markedly suppresses honeybee biochemical defence levels

Abstract

We examined the influence of bromfenvinphos, a commonly used acaricide, on activities of many metabolic enzymes affecting the biochemical defences/physiology of the western honeybee, Apis mellifera L. (Hymenoptera: Apidae), as well as on some metabolic compound concentrations, percentage of global DNA methylation, and Nosema spp. infection levels. Bromfenvinphos-treated workers had decreased haemolymph volumes and higher protein concentrations on their cuticle but lower protein concentrations in the haemolymph. They had higher global DNA methylation levels independent of the age-related variants. Bromfenvinphos decreased the activities of antioxidant enzymes (SOD, GPx, CAT, GST), acidic, neutral, and alkaline protease inhibitors and enzymatic physiological markers (AST, ALT, ALP), and concentrations of urea, uric acid, creatinine, cholesterol, glucose, Mg 2+ , and Ca 2+ in worker haemolymph, depending on the age of the bees. Protease activities were higher only in the haemolymph of young bromfenvinphos-treated bees in comparison with untreated bees. This compound decreased the activities of alkaline proteases and neutral protease inhibitors on the cuticle. Unexpectedly, in the treated bees, the activities of acidic and neutral proteases, and acidic and alkaline protease inhibitors, were higher in the young bees and lower in the older workers in comparison to the untreated group. The bromfenvinphos-treated workers were more heavily infested with Nosema spp. Thus, bromfenvinphos not only supressed many levels of biochemical defences, and therefore stress-resistance-related biochemical pathways but also visibly increased the Nosema spp. infection levels.

Imidacloprid markedly affects hemolymph proteolysis, biomarkers, DNA global methylation, and the cuticle proteolytic layer in western honeybees

“…This also suggested that honeybees can adapt to IMD through epigenetic mechanisms (Flores et al 2013;Dong et al 2013) or that at least the far-reaching IMD caused nonadaptive epigenetic changes occur. Similar epigenetic responses have already been observed in honeybees exposed to other harmful xenobiotics (Strachecka et al 2012b(Strachecka et al , 2016. On the other hand, the global DNA methylation level increased with honeybee age in the present study (Online Resource 2), which corresponds to the results of Lyko and Maleszka (2011) and Cardoso-Júnior et al (2018).…”

“…Similar to pathogens and other xenobiotics (Bajda et al 2014;Strachecka et al 2015Strachecka et al , 2016, ALT, AST, and ALP were downregulated, independent of the caste and age, when bees were exposed to IMD (Table II). This confirmed our hypothesis 3 and pointed out the harmful, physiological side effects of IMD.…”

“…Metabolic disturbances caused by harmful xenobiotics in honeybees decreased the activities of the following biomarkers: aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP) (Bajda et al 2014;Strachecka et al 2016). Exposure of bees to IMD should also change the activities of these biomarkers (hypothesis 3), but to our knowledge, this has not been studied.…”

Piperine as a new natural supplement with beneficial effects on the life-span and defence system of honeybees

“…Oxidative imbalance and decreased endogenous antioxidants lead to the release of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase enzymes (ALP) (Mehta et al, 2012). However, the mechanism of AST, ALP and ALT activation in bees is opposite to that in mammals (Bajda et al, 2014;Strachecka et al, 2014aStrachecka et al, , 2014bStrachecka et al, , 2016, as increased activities seem to be indicators of improved health and resistance (Łoś and Strachecka, 2018). In the current study, higher activities of these enzymatic biomarkers in the haemolymph of piperine-treated workers compared with untreated bees indicates a reduction of oxidative stress and support of the defence systems, similar to curcumin, caffeine, CoQ10 and vitamin C (Farjan et al, 2012;Strachecka et al, 2014aStrachecka et al, , 2014bStrachecka et al, , 2015).…”

“…The experiment was carried out on 8000 1-day-old worker bees (Apis mellifera carnica, Pollmann; collected from an apiary belonging to the University of Life Sciences in Lublin -51°1 3 ′ 31 ′′ N, 22°38 ′ 07 ′′ E), prepared according to the method of Strachecka et al (2016) in June and July 2017. Bees were settled into 200 wooden cages (40 bees/cage) with a volume of 576 cm 3 each (12 × 12 × 4 cm 3 , length/height/width), with a sliding front window, air vents located on the side and a feeder (a syringe with a modified adaptor) on the top.…”