Interaction between nutrition and gastrointestinal parasitism in sheep

Effects of gastrointestinal nematode infection on metabolism and nutrient utilisation in sheep are reviewed. Infection induces protein deficiency by increasing the demand for amino acids in the alimentary tract while reducing supply through depression of appetite. Mechanisms through which improved protein nutrition could improve the performance of the host are then discussed. Opportunities for capitalising on such effects are limited by our rudimentary understanding of the cell-mediated immune response in gastrointestinal epithelial tissue. Both resistance of the animal to larval establishment and performance in the face of larval challenge can be enhanced by improved protein nutrition. However, enhanced immune responses may not necessarily be synonymous with improved productivity except at luxurious levels of protein intake, because of apparently competing demands for protein. Such levels of protein nutrition are difficult to achieve in pasture-based systems, because of the protein limiting role of the rumen. Work with protein-protecting tannins to overcome this limitation is discussed. The much more limited evidence for effect of mineral nutrition, particularly copper (Cu), molybdenum (Mo), cobalt (Co) and phosphorus (P), on outcome of larval challenge is also reviewed.     

Influence of dietary amino acid level on performance,carcass quality and health of organic pigs reared indoors and outdoors

Abstract

The influence of dietary amino acids on performance and carcass quality was studied in 192 organic indoor and outdoor pigs given diets with different amino acid levels (recommended amino acid level, 7% and 14% lower) ad libitum in a two-phase feeding system. During phase 2, daily consumption of lysine, methionine+cystine and threonine was higher for outdoor than indoor pigs independent of amino acid level (p=0.002, 0.004 and 0.006, respectively). The outdoor pigs grew faster during phase 2 than the indoor pigs (p=0.001), although feed conversion ratio did not differ (p=0.358). Dressing percentage was higher for outdoor than for indoor pigs (p=0.011) but lean meat content did not differ (p=0.904). The health status of the pigs was evaluated and showed that the incidence of pigs seropositive to erysipelas was higher outdoors. Ascaris suum was present in both production systems, whereas Eimeria sp. only was found among outdoor pigs. The results indicate a discrepancy between pigs housed in different production systems rather than between pigs directed to different dietary amino acid levels. This suggests that growing/finishing pigs fed ad libitum can compensate for dietary amino acid levels lower than the current Swedish recommendations without affecting production results.     

Managing anthelmintic resistance: Is it feasible in New Zealand to delay the emergence of resistance to a new anthelmintic class?

The recent registration in New Zealand of the first new class of broad-spectrum anthelmintic, for use against nematode parasites of ruminants, in nearly three decades has raised the possibility that parasite management practices could be improved to minimise the emergence of resistance to the new drug. A review of knowledge pertaining to the selection of anthelmintic resistance in nematode parasites of sheep highlights a number of management practices which could be altered to achieve this.

A number of previously common practices such as whole-flock treatment of adult ewes around lambing, and treatment of lambs as they are moved onto pastures with low parasite contamination have been clearly identified as high risk for selecting resistant parasites. Once high-risk practices have been identified steps can be taken to either eliminate their use or mitigate the associated risk. Much of the focus on the management of resistance around the world is on the retention of susceptible genotypes in refugia. While approaches to retaining unselected parasites are likely to vary around the world, empirical studies indicate that the practice is likely to be effective at slowing the development of resistance. The challenge for farmers and advisors will be to strike a balance between retaining sufficient susceptible para-sites to usefully delay the development of resistance while not unduly compromising animal performance and farm profitability. The merits of combining different classes of anthelmintic in order to slow the development of resistance remains somewhat contentious in some countries. However, the attributes of oral anthelmintics are such that they seem likely to meet most, if not all, of the criteria for combinations to be highly effective at slowing the build-up of resistance in nematode parasites.

It is evident that considerable progress has been made in understanding the factors involved in selecting anthelmintic-resistant nematodes since the last broad-spectrum anthelmintic class was released in the early 1980s. Therefore, it should be possible to manage a new class of anthelmintic in such a way as to significantly extend its effective life. The challenge is likely to be in convincing farmers of the merits of adopting such pro-active strategies.     

冬季屠宰季节新疆白绒牦牛体内滞留寄生虫检查报告

[目的]在新疆牦牛冬季屠宰季节,对牦牛集中屠宰点的30份白绒牦牛内脏进行蠕虫剖解检查和粪检,对检查到的寄生虫进行分类鉴定.[方法]采用蠕虫剖检技术及粪便漂浮法.[结果]被检牦牛体内寄生虫感染率分别为96.6;(29/30)的线虫、13.3; (4/30)的绦虫、6.6; (2/30)的吸虫,总感染率为100;( 30/30);牦牛体内携带的优势种蠕虫类包括细颈线虫(Nematodirella longispiculata)、食道口线虫(Oesophagostomum columbianum)、捻转胃虫(Haemonchus contortus)、莫尼茨绦虫(Moniezia expansa)、双腔吸虫(Dicrocoelium lanceatum)、球虫(Eimeria intestinalis)等;其鉴定要点为线虫交合刺和口领、绦虫头节上吸盘和成熟节、吸虫生殖系统等部位.[结论]这些参数可为高山草原自然放牧的牦牛体内滞留寄生虫的驱虫及防治提供一定的依据.     

Parasites and hepatic lesions among pink salmon, Oncorhynchus gorbuscha (Walbaum), during early seawater residence

Juvenile pink salmon, Oncorhynchus gorbuscha (Walbaum), in the Broughton Archipelago region of western Canada were surveyed over 2 years for sea lice (Lepeophtheirus salmonis and Caligus clemensi), gross and microscopic lesions and evidence of infections with viruses and bacteria. The 1071 fish examined had an approximate ocean residence time no longer than 3 months. A high prevalence of degenerative liver lesions, renal myxosporean parasites and a low prevalence of skin lesions and sea lice were observed. No indications of viral or bacterial diseases were detected in either year. The monthly prevalence of sea lice in 2007 (18-51%) was higher than in 2008 (1-26%), and the infestation density exceeded the lethal threshold in only two fish. Degenerative hepatic lesions and renal myxosporean parasites occurred in approximately 40% of the pink salmon examined in June of both years, and the peak monthly prevalence of hepatocellular hydropic degeneration was greater in 2007 (32%, in May) than in 2008 (12%, in June). Logistic regression analysis found skin lesions and hepatocellular hydropic degeneration significantly associated with sea lice. Most parasites and lesions occurred during both years, but the prevalence was often higher in 2007. Fish weight was 35% less in June 2007 than in June 2008, but condition factor was not different. Further research is required to monitor inter-annual variations and aetiology of the liver lesions and to assess their potential role on pink salmon survival.     

Parasitic miticidal therapy

Parasites are a common cause of dermatological disease in the dog and cat. Knowledge of different miticidal options for the common parasitic diseases is imperative when choosing the appropriate treatment for a patient. This is especially important with the recent advent of safer and more effective antiparasitic medications. Diagnostic and therapeutic methods for Cheyletiella spp., Demodex spp., Notoedres cati, Sarcoptes scabei, and Otodectes cyanotis are discussed, with emphasis on protocols for miticidal therapies, as well as safety concerns and side effects. This information will allow the practitioner to choose the safest and most efficient treatment for parasitic skin disease in their small animal patients.     

额尔齐斯河东方欧鳊(Abramis brama orientalis Berg)寄生虫调查研究

按照鱼类寄生虫调查及研究方法,对额尔齐斯河(中国段)东方欧鳊(Abramis brama orientalis Berg)寄生虫种类及感染情况进行了调查研究。结果检出寄生虫8种:对盲囊线虫、复口吸虫、温氏指环虫、宽头鲤蠢绦虫、奇怪双身虫、复殖吸虫幼虫、泡吻棘头虫和毛细线虫。感染率分别达43.75%,37.5%,18.75%,18.75%,14.58%,12.5%,8.33%,2.08%。奇怪双身虫经检索鉴定,为我国单殖吸虫纲铗钩虫目双身虫科的一属、种新记录。     

图木舒克地区春夏季羊体外寄生虫感染情况调查

为了解图木舒克地区羊群体外寄生虫的种类及感染情况,对采集到虫体进行形态学观察,鉴定出11种寄生虫,其中蜱7种、螨2种,虱2种,优势虫种为扇头蜱属的血红扇头蜱(Rhipicephalus sanguineus)、短小扇头蜱(R.turanicus)图兰扇头蜱(R.pumilio).根据感染情况的调查结果,提出预防性驱虫措...     

Gastrointestinal Parasites of Urban Dogs in Perth, Western Australia

A study was conducted to determine the prevalence of gastrointestinal parasites in a sample of urban dogs in Perth and the knowledge of their owners about the control and zoonotic transmission of these parasites. Faecal samples (421), collected from dogs originating from five sources, were examined by microscopy and questionnaires administered to dog owners and managers/owners of pet shops. The prevalence of gastrointestinal parasitism was higher in pet shop puppies (51%), than in dogs from refuges (37%), breeding kennels (32.7%), veterinary clinics (15.6%) and exercise areas (5.3%). Protozoa, in particular Giardia, were detected more frequently (22.1%) than helminth parasites. After adjusting for other factors with multiple logistic regression, puppies less than 6 months of age, dogs living in households with more than one dog, and dogs from refuges were significantly more likely to be parasitized. The prevalence of Giardia was found to be directly associated with the number of doses of anthelmintics given in a year, increasing 1.2 times for each dose administered. The majority of owners were aware of the potential risk to human health from canine helminths, however only one third were aware of the means of transmission to humans. It is concluded that veterinarians can play an important role in increasing the level of awareness of canine zoonotic parasites.     

陕西5种圈养野生哺乳动物寄生虫调查研究

2006年4-5月通过采集动物排出的新鲜粪便,采用饱和盐水漂浮法、沉淀—漂浮法、粪便培养法等方法,对陕西省野生动物救护饲养研究中心的5种43头(只)哺乳动物寄生虫进行了调查,结果为5种动物均感染了寄生虫,所获虫体及虫卵或卵囊经鉴定共有22种,包括原虫3种、吸虫4种、绦虫3种、线虫8种、虱1种和蜱3种,隶属7目14科19属。结果显示这些野生动物的寄生虫感染普遍,寄生虫种类多样。