Fisheries and undernutrition

People eat fish directly, and they also consume it indirectly in the form of feed for livestock such as pigs and poultry. Despite widespread malnutrition in developing countries, the data indicate that on a per capita basis people in developed countries use about four times as much fish as people in less developed countries. Nevertheless, people in developing countries tend to be far more dependant on fish because it accounts for a far higher proportion of their animal protein intake.

The high levels of fish consumption in developed countries is partly due to their high levels of imports of fish products from developing countries. The export of large quantities of fish (and other food) from poor countries may help to account for the malnutrition in poor countries.

With adaptations in the production, processing, and distribution phases of operations, fisheries could be managed so as to help alleviate malnutrition. The potential was recognized by the World Conference on Fisheries Management and Development held in Rome in the summer of 1984 when it approved a new “Action Programme on the Promotion of the Role of Fisheries in Alleviating Malnutrition.”     

广西柳江河鱼类华支睾吸虫囊蚴感染情况

2008年3月～2009年3月,在广西柳江河段上的三江县、融安县、融水县、柳城县、柳州市和象州县设点,采集各地河道内的鱼类,用直接压片法和消化法检查其感染华支睾吸虫的情况。共捕获鱼16204尾,经鉴定分属9科27属35种,其中32种不同程度感染华支睾吸虫,感染率为10.5%,感染度为4.6个/g。麦穗鱼(Pseudoras bora parva)的感染率(21.5%)和感染度(9.9个/g)最高,其次为宽鳍鱲(Zacco platypus),感染率为17.8%,感染度为8.9个/g。各河段感染率间的差异有统计学意义,象州县河段感染率(12.3%)较高,三江县河段(9.1%)和柳州市区河段(9.7%)感染率较低。统计学分析表明,夏、秋两季鱼的感染率较高,春、冬两季较低;中、上水层鱼类的感染率较高,下水层鱼类较低;杂食性和草食性鱼类的感染率较高,肉食性鱼类较低。     

Determination of vitamin D3 and 25-hydroxyvitamin D3 in foodstuffs by HPLC UV-DAD and LC–MS/MS

In order to generate new data for vitamin D content for the Canadian Nutrient File, a method for the quantification of vitamin D₃ and 25(OH)D₃ in foodstuffs has been modified and improved. Vitamin D₃ was quantified using reverse phase liquid chromatography (LC) with UV-diode array detector (UV-DAD), while 25(OH)D₃ was measured by triple quadrupole mass spectrometry (APCI MS/MS). Quantification was by internal standards (IS) using vitamin D₂ and 25(OH)D₂. A Certified Reference Material (CRM-421 containing vitamin D₃) and a control sample (internally generated reference material of ground pork containing both vitamin D₃ and 25(OH)D₃) were used as validation and quality control tools. Limit of detection for both compounds was 0.04 μg/100 g. Accuracy for vitamin D in the CRM-421 was 99% (0.142 mg/kg for a target of 0.143, n = 10). Recovery of vitamin D₃ in ground pork was 97% (88% absolute recovery). For 25(OH)D₃, a recovery of 94% (73% absolute recovery) was obtained. Using this method, data for vitamin D₃ and 25(OH)D₃ content in a variety of foods (pork, beef, eggs, poultry, fish, and dinners) have been generated.     

Urotensin I-CRF-Urocortins: A mermaid’s tail

From the individual perspective of the two authors who were long-time colleagues of Karl Lederis at the University of Calgary, the events and personal interactions are described, that are relevant to the discovery of Urotensin I (UI) in the Lederis laboratory, along with the concurrent discovery of Urotensin II (UII) in the Bern laboratory and corticotropin-releasing factor (CRF/CRH) in the Vale laboratory. The fortuitous sabbatical experiences that put Professors Lederis and Bern on the track of the Urotensins, along with the essential isolation paradigm that resulted in the complete sequencing and synthesis of UI and UII are summarized. The chance interaction between Drs. Vale and Lederis who, prior to the publications of the sequences of UI and CRF, realized the sequence commonalities of these peptides with the vasoactive frog peptide, sauvagine, is outlined. Further, the relationship between the pharmacological studies done with UI in the Calgary laboratory and the more recent understanding of the biology and receptor pharmacology for the entire Urotensin I-CRF-Urocortin peptide family is dealt with. The value of a comparative endocrinology approach to understanding hormone action is emphasized, along with a projection to the future, based on new hypotheses that can be generated by unexplained data already in the literature. Based on the previously described pharmacology of the UI-CRF-Urocortin peptides in a number of target tissues, it is suggested that the use of current molecular approaches can be integrated with a ‘classical’ pharmacological approach to generate new insights about the UI-CRF-Urocortin hormone family.     

In situ studies on physiological and biochemical responses of four fishes with different trophic levels to toxic cyanobacterial blooms in a large Chinese lake

Physiological and biochemical responses of four fishes with different trophic levels to toxic cyanobacterial blooms were studied in a large net cage in Meiliang Bay, a hypereutrophic region of Lake Taihu. We sampled four fishes: the phytoplanktivorous Hypophthalmichthys molitrix and Aristichthys nobilis, the omnivorous Carassius auratus, and the carnivorous Culter ilishaeformis. Alterations of the antioxidant (GSH) and the major antioxidant enzymes (CAT, SOD, GPx, GST) in livers were monitored monthly, and the ultrastructures of livers were compared between the bloom and post-bloom periods. During the cyanobacterial blooms, the phytoplanktivorous fishes displayed only slight ultrastructural changes in liver, while the carnivorous fish presented the most serious injury as swollen endomembrane system and morphologically altered nuclei in hepatocytes. Biochemically, the phytoplanktivorous fishes possessed higher basal GSH concentrations and better correlations between the major antioxidant enzymes in liver, which might be responsible for their powerful resistance to MCs. This article provided physiological and toxicological evidences for the possible succession of fish communities following occurrence of toxic cyanobacterial blooms and also for the applicability of using phytoplanktivorous fish to counteract toxic cyanobacterial blooms in natural waters.     

Trophic transfer of paralytic shellfish toxins from the cladoceran (Moina mongolica) to larvae of the fish (Sciaenops ocellatus).

The dynamic transmission and transformation of paralytic shellfish toxins (PSTs) from the toxic dinoflagellate Alexandrium tamarense to the cladoceran Moina mongolica and subsequently to the larvae of the fish Sciaenops ocellatus were investigated under laboratory conditions. The results showed that PSTs could be transferred to S. ocellatus when they preyed on PST-containing M. mongolica. During the experimental period, A. tamarense, M. mongolica and the digestive glands of the fish larvae contained C(1/2) toxins, and the viscera of S. ocellatus contained neoSTX. The proportion of beta toxin (C2) in C(1+2) toxins increased when PSTs were transferred from A. tamarense to M. mongolica, but in the subsequent transfer from M. mongolica to S. ocellatus the proportion of alpha toxin (C1) increased. During depuration, the contents of C1 and C2 toxins in fish larvae decreased with the duration of depuration, but neoSTX remained relatively constant. The present results indicated that, using a cladoceran as the vector, PSTs can be transferred from toxic algae to a high trophic level fish and metabolized in the fish. Future work should address the metabolic characteristics of PSTs in cladocerans and the end result when they are transferred to fishes.     

富含DHA的鱼油制剂遗传毒性和亚急性毒性研究

目的研究富含DHA的鱼油制剂对哺乳动物的遗传毒性和亚急性毒性的影响,了解富含DHA的鱼油制剂可能存在的远期危害和毒性作用。方法采用小鼠骨髓细胞微核试验和大鼠亚急性毒性试验,观察3.33g/kg.BW、1.67g/kg.BW和0.83g/kg.BW剂量的富含DHA的鱼油制剂对小鼠骨髓细胞微核率的影响及对产生亚急性毒性作用。结果通过小鼠骨髓细胞微核试验未观察到富含DHA的鱼油制剂有明显的诱导骨髓细胞形成微核的作用;通过大鼠亚急性毒性试验未观察到与受试物有关的毒性作用的最大剂量。结论实验未观察到富含DHA的鱼油制剂对哺乳动物产生遗传毒性和亚急性毒性作用,也未发现其可能存在的远期危害,有关其在其它方面的毒理学作用还有待进一步研究。