Seasonal variation of thermophilic campylobacters in lambs at slaughter

A survey of the isolation rate and population size of thermophilic campylobacters in lambs at slaughter was carried out to determine the seasonal variation of thermophilic campylobacters in ovine hosts. Isolation rates determined by enrichment methods were always higher than those using direct plating onto selective agar and showed that Campylobacter could be isolated from 91·7% ( n = 360) of samples from the small intestine of the lambs. Enumerations (MPN), done monthly over a 2-year period, averaged 4·00 log 10 ( n = 1080, S.D . 0·16) campylobacters g⁻¹ fresh weight (fw) intestinal contents with some samples giving values higher than 7 log MPN gfw⁻¹. These results show that the prevalence of thermophilic campylobacters in sheep intended for slaughter is much higher than previously reported. Statistical analyses showed that there was a significant seasonal periodicity in the Campylobacter populations in the small intestines of lambs at slaughter ( P = 0·004) but that there was no statistical relationship with environmental parameters such as minimum and maximum temperature, rainfall or hours of sunshine. In an analysis along the length of the intestinal tract of lambs, campylobacters were isolated from 80% of small intestine and 30% of rumen samples, but not from the true stomach, large intestine or caecal samples. A survey of sheep grazing on salt marsh, fell (upland) and farm pasture showed that the isolation rate of thermophilic campylobacters in fresh faeces was substantially lower (29·3% ( n = 420)) than that from the small intestine of lambs at slaughter. No significant difference (>0·05) was found between the isolation rate of campylobacters from faeces sampled in late spring/early summer and autumn, nor between the different types of grazing.     

The seasonal variation of thermophilic campylobacters in beef cattle, dairy cattle and calves

The epidemiology of clinical cases of campylobacter in temperate climates shows a striking seasonality. In the search for a seasonal environmental reservoir changes in the carriage rate and population size of campylobacters in bovine hosts with time have been measured. Most probable number (MPN) methodology was used to enumerate thermophilic campylobacters in samples taken from the small intestines of beef cattle at slaughter and the fresh faeces of four dairy herds and new-born calves. Statistical analyses revealed significant evidence for seasonal periodicity in the data from dairy herds ( P = 0·044). Not only was there a departure from constancy within a 12-month interval but these data revealed a true seasonality, that is, the same periodicity in numbers from one year to the next. Each herd had two peaks per year, in approximately spring and autumn. Peaks coincided in herds on neighbouring farms but those on farms in the north preceded those on farms in the south by 2 and 1 months, respectively ( P = 0·0057). Intestinal carriage by beef cattle at slaughter was 89·4% ( n = 360) with an average MPN campylobacters per gram fresh weight (MPN gfw⁻¹) of 6·1 × 10². Average MPN gfw⁻¹ in faeces from the dairy herds and calves were 69·9 ( S.D. 3) and 3·3 × 10⁴ ( S.D. 1·7 × 10²). There was no evidence of seasonal periodicity in the size of the campylobacter population in beef cattle at slaughter. Calves were campylobacter free at birth but became colonized within a few days.     

Seasonal variation of thermophilic campylobacters in sewage sludge

The seasonal variation of thermophilic campylobacters in Lancaster's sewage sludge was studied over a 21 month period. The numbers in fresh sludge (from primary sedimentation) vary between approximately 200 and 5000/100 ml for most of the year but there was a large increase in May and June (in May 1988 there were 42100 campylobacters/100 ml which is 17 times more than in the preceding April). In 1989 there was a similar May/June peak but with lower numbers. This seasonal variation, measured by environmental monitoring, reflects the incidence of infections in the community. The same pattern was found in 2-d old sludge but the numbers were substantially lower (40% lower over the experimental period).
Thermophilic campylobacters were virtually absent from digested sludge and sludge prior to land distribution. Survival experiments confirm that campylobacters survive for only a few hours in both sterile and unsterile digested and undigested sludge. These results suggest that it is safe to dispose of Lancaster's digested sludge on land but there is still uncertainty about the ability of campylobacters to survive in sludge in the viable but non-culturable form.     

Seasonal variation of thermophilic campylobacters in sewage sludge

The seasonal variation of thermophilic campylobacters in Lancaster's sewage sludge was studied over a 21 month period. The numbers in fresh sludge (from primary sedimentation) vary between approximately 200 and 5000/100 ml for most of the year but there was a large increase in May and June (in May 1988 there were 42,100 campylobacters/100 ml which is 17 times more than in the preceding April). In 1989 there was a similar May/June peak but with lower numbers. This seasonal variation, measured by environmental monitoring, reflects the incidence of infections in the community. The same pattern was found in 2-d old sludge but the numbers were substantially lower (40% lower over the experimental period). Thermophilic campylobacters were virtually absent from digested sludge and sludge prior to land distribution. Survival experiments confirm that campylobacters survive for only a few hours in both sterile and unsterile digested and undigested sludge. These results suggest that it is safe to dispose of Lancaster's digested sludge on land but there is still uncertainty about the ability of campylobacters to survive in sludge in the viable but non-culturable form.     

Effect of age and sex on digestive tract morphometry of guinea fowl (Numida meleagris L.)

As guinea fowl age, their body weights and length of the esophagus and crop increased significantly, and relative length (cm x 100 g b.w(-1)) of the small intestine, caeca and total intestine decreased significantly (P < or = 0.05) in males and females. In addition, 52-week-old males had a significantly higher percentage length of rectum and heart weight, and females a significantly higher gizzard weight compared to 13-week-old birds. Compared to females, adult males differed significantly (P < or = 0.05) in the length of caeca and also in the proportion of the gizzard, proventriculus, heart and liver in total weight.     

The colonization of turkeys by thermophilic campylobacters

The rate at which five broods of turkey chicks became colonized by thermophilic campylobacters was investigated. Day-old chicks were normally free of campylobacters on arrival on the farm with colonization beginning within 7 d. The carriage rate was 100% by day 14 in three of the broods and by day 21 in the other two. Higher carriage rates were obtained with enrichment procedures than with direct plating. Two broods were investigated over an extended interval for the number of campylobacters shed in their faeces. In brood A, campylobacters increased from day 1 to day 14 concomitant with increases in the carriage rate and in the number of chicks with diarrhoea. By day 39, when the birds were sold to other farms, the excretion rate had reached 6 × 10⁷ campylobacters g⁻¹ fresh faeces. Brood B was monitored over 91 d and showed peaks in Campylobacter numbers on days 19 and 75, corresponding to peaks in the number of diarrhoeic samples. The introduction of new birds into the brood resulted in an increase in the Campylobacter population and in the number of birds with diarrhoea. Campylobacter jejuni was the only species isolated but comprised several different biotypes. Analysis of the number of campylobacters at different sites along the gastrointestinal tract of mature turkeys at slaughter showed that numbers increased with distance from the beak and were highest in the caeca.     

社鼠和褐家鼠消化道长度和重量的季节变化

测定了浙江金华的社鼠和褐家鼠消化道长度和重量的季节变化。野生社鼠消化道各器官无论长度不审重量都有明显季差异,在寒冷的冬季具有相对较大的小肠、大肠、盲肠、雄性社鼠的消化道长度在秋季由于食物条件的改善而明显下降,但雌性社鼠由于在秋季仍有繁殖负担,其消化道长度下降不明显,而家栖的褐家鼠只有总消化道、小肠和大肠的长度有季节差异,冬、春季高于夏、秋季。消化道形态季节变化与温度、食物条件和繁殖有关。     

SEASONAL AND DEMOGRAPHICAL VARIATION IN INTESTINAL HELMINTH INFECTION OF GREYWING FRANCOLIN

Little, R.M., Verster, A. & Crowe, T.M. 1993. Seasonal and demographical variation in intestinal helminth infection of Greywing Francolin. Ostrich 64:178-181.

The proportion of the population carrying intestinal parasites (prevalence of infection) and the mean number of parasites per host within the host population (worm burden) for 312 Greywing Francolin Fran-colinus africanus were recorded on the Stormberg Plateau, eastern Cape Province, during April 1989-De-cember 1990. Most Greywing (86%) had helminths in their small intestine or caeca. Variation in levels of helminth infection (i.e. both prevalence and burdens) was independent of host sex. Nematodes were confined to the caeca where they were present in high numbers throughout the year with two peaks during June-August and November-January. The prevalence and worm burdens of nematodes were independent of host age Nematodes were more prevalent than cestodes. The prevalence and number of cestodes in the small intestine were highest during September-February and Faked during November-December. Levels of prevalence of cestodes were significantly higher in juvenile Greywing than in adults during the austral winter (May-July). The number of cestodes was consistently, but not significantly, higher in juveniles than in adults. Greywing body mass and population density were not significantly correlated with worm burdens.     

Gross intestinal morphometry and allometry in primates

Although it is generally assumed that among mammals and within mammal groups, those species that rely on diets consisting of greater amounts of plant fiber have larger gastrointestinal tracts (GIT), statistical evidence for this simple claim is largely lacking. We compiled a dataset on the length of the small intestine, caecum, and colon in 42 strepsirrhine, platyrrhine, and catarrhine primate species, using specimens with known body mass (BM). We tested the scaling of intestine length with BM, and whether dietary proxies (percentage of leaves and a diet quality index) were significant covariates in these scaling relationships, using two sets of models: one that did not account for the phylogenetic structure of the data, and one that did. Intestine length mainly scaled geometrically at exponents that included 0.33 in the confidence interval; Strepsirrhini exhibited particularly long caeca, while those of Catarrhini were comparatively short. Diet proxies were only significant for the colon and the total large intestine (but not for the small intestine or the caecum), and only in conventional statistics (but not when accounting for phylogeny), indicating the pattern occurred across but not within clades. Compared to terrestrial Carnivora, primates have similar small intestine lengths, but longer large intestines. The data on intestine lengths presented here corroborate recent results on GIT complexity, suggesting that diet, as currently described, does not exhaustively explain GIT anatomy within primate clades.     

肠道菌群变化对实验小鼠肠黏膜免疫的影响

目的探讨肠道菌群变化对肠黏膜相关淋巴组织的影响。方法通过变性梯度凝胶电泳（Denatu-ring gradient gel electrophoresis,DGGE）法研究了三种不同级别实验小鼠即清洁级小鼠、SPF小鼠和普通小鼠肠道菌群的组成,并用免疫组织化学（immunohistochemistry,IHC）方法研究了此三种不同级别的实验小鼠肠黏膜相关淋巴组织sIgA阳性细胞分布情况。结果普通小鼠肠道细菌种类最多,其sIgA阳性细胞分布最多,肠道不同部位之间sIgA分布情况差异有显著性（P〈0.05）,小肠和大肠之间的阳性细胞分布差异极显著（P〈0.01）;其次是清洁级小鼠,其肠道不同部位之间菌种组成差异无显著性,小肠和大肠之间的阳性细胞分布差异有显著性（P〈0.05）;SPF小鼠肠道细菌种类最少,故其sIgA阳性细胞分布最少,且其肠道不同部位之间菌种组成差异无显著性,小肠和大肠之间的阳性细胞分布差异无显著性（P〉0.05）。结论随着动物微生物控制级别的增高,肠道微生物多样性递减;sIgA阳性细胞与肠道细菌种类正相关。     

The response of digestive proteases to abrupt salinity decrease in the euryhaline sparid Sparus aurata L

The response of the digestive proteases to abrupt salinity change was studied in juvenile gilthead sea bream (Sparus aurata) for 15 days after transfer from 33 per thousand to 21 per thousand. Salinity decrease affected significantly neither the activity of total acid proteases in stomach, nor the activities of total alkaline proteases and major serine proteases--trypsin and chymotrypsin--in the alkaline part of the intestine. The activity of the major proteases was significantly different between the alkaline segments of the intestine, with the posterior intestine presenting the highest activities followed by the pyloric caeca. This distribution pattern remained unaffected by salinity decrease. Notably, salinity change led to significant alterations in elastase and carboxypeptidase activity. The changes were more prominent in the upper part of the intestine (pyloric caeca and anterior intestine) than in the posterior intestine. In pyloric caeca significant alteration of carboxypeptidase A and B activities was observed, elastase changes were confined to anterior intestine together with alterations in carboxypeptidase B activity, while in posterior intestine the changes were restricted to carboxypeptidase A activity. The results are discussed in relation to the osmoregulatory action of the intestinal segments and dietary protein digestion.     

Importance of gender and sex hormones in regulation of susceptibility of the small intestine to peroral infection with Toxoplasma gondii tissue cysts.

This study was performed to investigate whether the gender and sex hormones play a role in susceptibility of the small intestine of mice to peroral infection with Toxoplasma gondii tissue cysts. Female animals died significantly earlier than males, and early mortality of females was associated with greater numbers of tachyzoites and severe necrosis in their small intestines. Treatment of female mice with testosterone resulted in markedly reduced intestinal parasite numbers and pathology. Thus, the gender and sex hormones are important factors for determining susceptibility of the small intestine to T. gondii infection.     

Digestive strategies in the South American subterranean rodent Ctenomys talarum

Ctenomys talarum is a subterranean herbivorous rodent which due to its particular life style is frequently exposed to variations in surface environmental conditions (i.e. food quality and availability, temperature). Thus, unlike other subterranean rodents, C. talarum has to buffer both the surface and burrow challenging environmental conditions. We studied the occurrence of digestive strategies at different levels of C. talarum living in their natural habitat. We determined the dimensions of different parts of the gastrointestinal tract and organs along as the activity of key digestive enzymes (disaccharidase, N-aminopeptidase) in different parts of the gut in individuals seasonally caught. The results show that C. talarum exhibits characteristics in the gut at the biochemical level (high disaccharidase activities in small intestine, high N-aminopeptidase activity in the caecum and large intestine, and a seasonal differential modulation of N-aminopeptidase activity in small and large intestines), which could represent adaptive strategies to face seasonal variations in key environmental factors.     

Histopathology due to the presence of Gracilisentis gracilisentis in Dorosoma cepedianum (Le Sueur)

The acanthocephalan, Gracilisentis gracilisentis , infects the pyloric caeca and small intestine of Dorosoma cepedianum . Sections of intestinal tissue were examined microscopically and indicated pathological lesions were produced by G. gracilisentis in the mucosa and submucosa. G. gracilisentis occurs during the period of seasonal mortalities of D. cepedianum and may be responsible for such mortalities.     

长爪沙鼠的代谢率与器官的关系

我们测定了野生长爪沙鼠（Meriones unguiculatus)的基础代谢率和冷诱导的最大代谢率,分析了动物体内11种器官或组织的大小与代谢率的关系。长爪沙鼠的基础代谢率为118.10mlO2/h,最大代谢率为659.83mlO2/h。经过残差分析表明,基础代谢率并不与任何一种器官或组织相关,而最大代谢率与小肠湿重（n=20,r=-0.478,P=0.033)和消化道全长（n=20,r=-0.487,P=0.030)显著相关,表明体内器官重量的差别并不是造成种内基础代谢率差别的原因;体内存在着与最大代谢率相关的“代谢机器”,消化系统（特别是小肠）是这一代谢机器的重要组成部分,但代谢机器的大小并不能通过基础代谢率反映出来。基础代谢率与最大代谢率不相关,因此不支持“较高的基础代谢率能够产生较高的非基础代谢率（最大代谢率等）”的假设。     

麻鸭肠道无芽胞厌氧菌定性、定量和定位研究

本研究采用气、液相色谱分析法(Gas-Liquid Chromatography,GLC)分析细菌代谢产物,结合微生物学鉴定和微量快速生化反应,在我国首次定量测定了麻鸭小肠、大肠每克内容物4种厌氧菌的菌数,初次确定在小肠有卵形类杆菌、发酵乳杆菌、两歧双歧杆菌、空肠弯曲杆菌4个种;在大肠有卵形类杆菌、多形类杆菌、解脲类杆菌、发酵乳杆菌、干酪乳杆菌、植物乳杆菌、短双歧杆菌、空肠弯曲杆菌和粪弯曲杆菌9个种。类杆菌和乳杆菌等是麻鸭肠道正常微生物群。     

Intermittent shedding of thermophilic campylobacters by sheep at pasture

The rates at which sheep on different types of pasture shed campylobacters in their faeces were measured over 12 months. Overall, shedding of campylobacters at pasture was between a third and a half of the carriage rate (92%) of the intestines of sheep at slaughter. Shedding was highest during saltmarsh grazing, followed by upland fell and farm grazing. The rate of shedding varied at different times of the year, with the highest rates (100%) coinciding with lambing, weaning, and movement onto new pasture. The lowest rates (0%) occurred when sheep were fed on hay and silage. On the farm, low rates occurred during the whole of gestation, both when the sheep were indoors and outdoors. Campylobacter jejuni was the main species isolated and survived for up to 4 d in sheep faeces. Lambs became colonized by Campylobacter within 1-5 d of being born. Ewes, which were not shedding campylobacters prior to lambing, started to shed after lambing, and ewes which were shedding low numbers of Campylobacter before lambing, increased the numbers of bacteria being shed after lambing.     

Effects of temperature and infection with Eimeria ochrogasteri on digestive organs of the prairie vole, Microtus ochrogaster

Prairie voles, Microtus ochrogaster, were infected with Eimeria ochrogasteri and exposed to 2 environmental temperatures, 5 and 22 C. Dry weights of the small and large intestines increased by 33% and 19%, respectively, in infected animals. Infected animals also exhibited a 14% decrease in cecal length compared to uninfected animals. The interaction between temperature and infection affected the length of the small intestine. Infected animals maintained at 5 C had longer small intestines than both infected animals housed at 22 C, and uninfected animals at 22 or 5 C. Furthermore, the dry weight of the small intestine was affected by a 3-way interaction (infection, temperature, and sex). Temperature affected stomach and liver dry weights, as well as lengths of the small intestine and cecum. Stomach and liver dry weights, as well as small intestine lengths, were greater in those animals held at 5 C, whereas cecum lengths decreased. Prepatency, patency, and total oocyst production were not affected by temperature; however, infected animals held at 5 C exhibited diarrhea during the patent period.     

Intestinal length of three California pinniped species

Forty-eight intestinal tracts, extracted from both sexes of California sea lions, Harbour seals and Northern elephant seals, were measured. The majority of intestinal tracts were removed from stranded animals that died from various causes. The sea lions and elephant seals, approximately equal in size, were larger than the Harbour seals. All species possess a small intestine which is significantly longer than even the entire gastrointestinal tract of herbivores of comparable size. Elephant seal small intestines, averaging approximately 25 times the seal's body length, were considerably longer than the small intestines of either sea lions (averaged more than 18 times the body length) or Harbour seals (averaged nearly 16 times the body length). However, the large intestines of elephant seals were shorter than either of the other two species. Among the sea lions and Harbour seals the large intestines were approximately equal in length. Sea lions and Harbour seals also showed a close correlation between standard length and total intestinal length. Among elephant seals these two parameters showed greater variability. The functional significance of the extremely long small intestine remains unclear. Certainly, the large body mass and high energy requirements of these animals has contributed to the development of a long intestinal tract. It also appears likely that diet and the high motility rate of digesta influenced the intestinal development. Comparatively, the significantly shorter large intestine of elephant seals probably relates to this species' remarkable capabilities in water conservation and metabolic water retention.     

Seasonal plasticity of duodenal morphology and histology in Passer montanus

When facing seasonal environmental changes, flying birds and small mammals may develop adaptive gastrointestinal changes to optimize their digestive and absorptive strategies to meet the changing of physiologic needs. As a main component of gastrointestinal tract, small intestine is extraordinarily sensitive to food abundance, food quality, and other environmental factors. However, the detailed morphological adaptations of the small intestine during seasonal changes are largely unknown. Here, we studied the morphological and histological dynamics of duodenum from Passer montanus in Zhalong Nature Reserve in China during seasonal changes. The luminal and wall cross-section area were greater in spring and autumn than that in summer. Villus height and width went up to peak values in winter and showed similar seasonal dynamic changes with that of mucosal thickness, while villus atrophy accompanied by the deepest crypt depth was easily detected in summer. Epithelium thickness was coincident with villus atrophy except a sharp increase in summer. Submucosal thickness was negatively correlated with that of mucosa, while the size, but not total number, of duodenal glands was altered to reflect to seasonal changes. Neither the inner circular nor the outer longitudinal muscle showed seasonal morphological changes, indicating the relatively stable plasticity of intestine muscle structures. Taken together, we propose that phenotypic flexibility in digestive morphology and histology enables small birds to cope with remarkable seasonal changes.