Movement behaviour of large female yellow European eel (Anguilla anguilla L.) in a freshwater polder area

Due to a recruitment decline of more than 90% in 30 years, the European eel (Anguilla anguilla L.) has been classified by IUCN as critically endangered. Although the species has been studied intensively to obtain knowledge to improve management, studies about the resident yellow stage are relatively scarce. In this study, 52 large female yellow eels were tagged with acoustic transmitters in a Belgian polder system and tracked by a network of 23 automatic listening stations. We studied both circadian and seasonal movement patterns and the effect of environmental variables on these patterns. Large female yellow eels were most active at night in late summer and early autumn. A generalised linear mixed model showed that their movement is only slightly influenced by environmental variables. Moreover, as yellow eels show high site fidelity (i.e., the majority was detected only in the habitat type of their catch‐release location), they do not encounter many human‐induced connectivity problems in polder systems, which makes these systems highly suitable as eel growth habitat. These results can contribute to an effective eel management regarding habitat protection and restoration.     

Banishing barberry: The history of Berberis vulgaris prevalence and wheat stem rust incidence across Britain

Wheat stem rust, caused by the fungus Puccinia graminis f. sp. tritici (Pgt), is a notoriously damaging disease of wheat and barley. Pgt requires two hosts to complete its lifecycle; undergoing asexual reproduction on cereal crops and completing sexual reproduction on Berberis spp. The latter stage of its lifecycle is of particular importance in temperate regions such as western Europe, where asexual urediniospores are unable to survive cold winter weather. In the past, the crucial role of Berberis in the lifecycle of stem rust led to intensive eradication campaigns, initially carried out by farmers in the face of hostile scientific opinion. In the United Kingdom, common barberry (Berberis vulgaris) is today a relatively rare plant. Stem rust is, however, currently experiencing a resurgence; at the same time, there has been a general increase in the prevalence of barberry and an upsurge in its planting which, in the United Kingdom, is associated with attempts to encourage the endangered barberry carpet moth (Pareulype berberata). This article situates current developments within a broader chronological framework, examining changing attitudes towards barberry and rust in England in the past and the history of the plant's use and cultivation. It assesses how widespread B. vulgaris really was in the environment historically, and thus the scale of its eradication. We suggest that Berberis was never widely established as an archaeophyte in the United Kingdom. Current attempts to re-establish it are based on a misunderstanding of the plant's historical status and could potentially pose a serious threat to food security.     

Stable isotopes and gut contents indicate differential resource use by coexisting asp (Leuciscus aspius) and pikeperch (Sander lucioperca)

Differential use of habitat and prey resources is an important mechanism that may allow coexistence of sympatric species. Unlike interactions between smaller cyprinid and percid fishes, the resource use by coexisting predatory asp (Leuciscus aspius) and pikeperch (Sander lucioperca) is relatively unknown. Here, gut content and stable isotope analyses were used to study ontogenetic dietary shifts and interspecific trophic niche overlap between asp and pikeperch coexisting in two reservoirs. The hypothesis that both species show an ontogenetic dietary shift from small invertebrates to large fish prey, but at the same time use different prey resources to reduce potential competitive interactions, was validated. The isotopic niches of the two predators showed no, or only a moderate, degree of overlap (0%–65%). The ontogenetic changes in the degree of interspecific isotopic niche overlap were different in the two reservoirs, suggesting that trophic segregation can be dynamic and variable among systems. Gut contents revealed that small (<100 mm standard length) asp consumed mostly terrestrial invertebrates and emerged aquatic insects, whereas small pikeperch foraged on zooplankton, larval and pupal stages of aquatic insects and fish. Larger individuals (>100 mm) of both species were predominantly piscivorous, with asp consuming more cyprinid prey and pikeperch more percid prey. Coexisting asp and pikeperch populations are able to utilise different prey resources, thereby reducing potential negative competitive interactions.     

Comparison of Chemical Composition and Biological Properties of Essential Oils Obtained by Hydrodistillation and Steam Distillation of Laurus nobilis L.

Plant Foods for Human Nutrition - The purpose of this study was to compare the yield, chemical composition, antimicrobial and antioxidant properties of essential oils isolated from leaves of Laurus...     

一种面向育种家的新型台式棉籽脱绒机

正棉籽酸脱绒会危害育种家人身安全和潜在环境。需要1种无需用酸,能有效去除棉短绒且对棉种萌发无不利影响的脱绒方法。为了优化棉籽机械脱绒流程,美国农业部农业研究中心(USDA-ARS)棉花生产与加工部门(Lubbock,Texas)研发创制了一台棉籽机械脱绒样机(图1,图2)。测试设计了应用7种滚筒衬垫(1种是不用任何研磨材料,其余6种分别采用不同的研磨材料)、1个或2个辊刷"擦     

Otolith elemental characteristics of whitefish (Coregonus lavaretus) from brackish waters of the Gulf of Bothnia,Baltic Sea

To investigate whether European whitefish (Coregonus lavaretus) groups in the brackish (≤7%) Gulf of Bothnia (Baltic Sea) express specific otolith elemental characteristics, concentrations of elements (Ca, Ba, Sr, Zn, Mn, Fe) in whole otoliths were studied by inductively coupled plasma‐optical emission spectrometry. Whitefish (N = 67) were sampled from six different latitudinal sites; four in the sea and two in rivers along the west coast of Finland, and from a fresh water lake for comparison. The concentration of several elements showed significant differences among sampling sites. Otolith Ba concentrations were higher at the northern sampling sites compared to the southern ones, thereby showing negative association to capture‐habitat salinity. In contrast, otolith Sr and Zn concentrations were lower at the northern sampling sites, thereby associating positively to capture‐habitat salinity. Otolith Mn concentrations did not associate with latitude or salinity but markedly varied between sampling sites. Elevated Fe concentrations occurred in fish otoliths from the two northernmost sites. Ca concentrations were at the same levels in otoliths from all whitefish samples. Otoliths of whitefish from the lake had very high Ba and low Sr concentrations compared to concentrations in otoliths from whitefish in the sea and rivers. Our results show that otolith elemental characteristics of whitefish vary considerably at various geographic scales showing high potential for population identification using elemental fingerprints. Analysis of otolith elemental characteristics may therefore provide an efficient tool for the identification of main areas of residence, spawning locations, and migration routes, thus contributing towards the sustainable management of whitefish stocks.     

Effect of fish meal replacement with Carinata Brassica carinata in low animal protein diets of rainbow trout Oncorhynchus mykiss (Walbaum) on trypsin activity,protein and amino acid digestibility and bioavailability

Replacement of >25% of fish meal (FM) with aerobically converted carinata meal (ACCM) in low (200g/kg) animal protein (reference = 200g/kg FM) diets of rainbow trout Oncorhynchus mykiss resulted in reduced growth, partly due to reduced feed consumption and protein utilization. In this study, we determined the effect of FM replacement with ACCM on trypsin activity, apparent digestibility coefficients (ADCs) of protein, and essential amino acid (EAA) or conditionally essential amino acid (CEAA) ADCs and bioavailability. Replacement of FM did not alter protein ADCs or trypsin activity. Replacement of >25% FM reduced all EAA and CEAA ADCs except for arginine and leucine which were only reduced by 75% FM replacement. Only serum free lysine and muscle free histidine were reduced by >25% FM replacement. Muscle free lysine was only reduced by 75% FM replacement. Replacement of FM reduced EAA peak concentrations and resulted in slower release of EAAs in serum. Cumulative total EAAs in serum and muscle decreased with FM replacement. Ratios of EAAs to lysine showed that tryptophan was the most limiting EAA. However, isoleucine, leucine, methionine and phenylalanine were also inadequate for muscle synthesis for the first 9–12 hr following force‐feeding. Optimal time for protein synthesis was ≥36 hr. Although any level of FM replacement did not reduce protein ADCs and trypsin activity, replacement of ≥25% FM reduced EAA ADCs and bioavailability of lysine and histidine, which partly contributed to the observed differences in growth.     

Decoding attraction: Improving vine weevil monitoring by exploiting key sensory cues

BACKGROUND

Monitoring is an integral component of integrated pest management (IPM) programmes used to inform crop management decisions. Vine weevil, Otiorhynchus sulcatus F. (Coleoptera: Curculionidae), continues to cause economically significant losses in horticultural crops due to an inability to reliably detect the presence of this species before crop damage occurs. To improve vine weevil monitoring we investigated the behavioural responses of adult vine weevils to visual (monitoring tool shade/colour, height and diameter as well as the effect of monitoring tool and plant density) and olfactory (host plant and conspecifics) cues under glasshouse conditions.

RESULTS

Monitoring tool shade, height and diameter all influenced monitoring tool efficacy, with individuals exhibiting a preference for black, tall and wide monitoring tools. The total number of individuals recorded in monitoring tools increased with monitoring tool density. By contrast, plant density did not influence the number of individuals recorded in monitoring tools. Yew-baited monitoring tools retained a larger number of individuals compared to unbaited ones. Similarly, more vine weevils were recorded in monitoring tools baited with yew and conspecifics than in unbaited monitoring tools or those baited with only yew. Baiting monitoring tools with conspecifics alone did not enhance the number of vine weevils recorded in monitoring tools.

CONCLUSIONS

Our study confirms that visual and olfactory cues influence vine weevil behaviour. This provides information on key factors that influence vine weevil monitoring tool efficacy and can be used to inform the development of a new monitoring tool for this pest. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Ultrasound-guided core needle biopsy in dogs with thyroid carcinoma

Currently, a histological diagnosis of highly vascularized canine (c) thyroid carcinoma (TC) is primarily obtained following excisional biopsy (EB) through thyroidectomy. Non-EBs are contraindicated in unresectable invasive cTCs due to their highly vascularized nature, which subsequently, lack histological diagnosis. We hypothesised ultrasound-guided core needle biopsy (UGCNB) to be a safe biopsy technique to obtain an accurate histological diagnosis in unresectable TCs. Nine client-owned dogs with suspected naturally occurring TC, presented for surgical excision, were included. First, a UGCNB was taken from the cervical tumour, followed by EB. Haemorrhage following UGCNB was evaluated preoperatively and once the tumour was surgically exposed by visual inspection and ultrasonography. Histological analysis, including cell organisation, tumour capsular and vascular invasion, and immunohistochemistry were performed and compared between both biopsy specimens (i.e., UGCNB and EB) of the same dog. Pre- and peroperative visual inspection revealed minor, localised haemorrhage, subsequent to the UGCNB, in 7/9 dogs. Histology of the EBs confirmed TC in 8/9 dogs and was inconclusive in 1/9 dogs. Histology of the UGCNBs revealed neoplastic thyroid tissue in 7/9 UGCNBs and was inconclusive in 1/9 UGCNBs. The remaining UGCNB contained no mass related tissue and was, therefore, excluded. Histological parameters (i.e., cell organisation, tumour capsular and vascular invasion) were not concordant between 6/8 included UGCNBs and their respective EB. Immunolabelling for thyroglobulin and calcitonin was concordant between all eight included UGCNBs and their respective EB. The remaining evaluated immunohistochemical markers (i.e., cyclooxygenase-2 [COX-2], P-glycoprotein and vascular endothelial growth factor [VEGF]) were concordant between the included UGCNBs and the EBs in 6/8 dogs. To conclude, UGCNBs can be safely obtained in suspected cTCs and enable a reliable diagnosis of the thyroid origin, thyroid cell origin and potential therapeutic markers such as COX-2, P-glycoprotein and VEGF. Subsequently, UGCNB enables clinicians to establish an individually tailored treatment plan in dogs with unresectable TC.