Modelling the relationships of egg weight, specific gravity, shell calcium and shell thickness

1. The relationships between egg weight, egg specific gravity, shell weight, shell calcium and shell thickness of 800 eggs from 8 treatments were expressed using mathematical models. 2. The equations describing the relationships were on the basis of any two independent variables predicting the remainder. 3. Of 10 possible models, 4 had high co-efficients of determination (R2 greater than 0.80) for each predicted dependent variable. 4. The two independent variables in each of these 4 models were, in turn, egg weight and specific gravity, egg weight and shell weight, egg weight and shell thickness, and specific gravity and shell weight. 5. The best model was that having egg weight and specific gravity as independent variables, with R2 values of 0.94, 0.88, and 0.85 for predicted shell weight, shell calcium, and shell thickness, respectively. Moreover, egg characteristics can be measured non-destructively by this model, whereas the other three require destruction of the egg.     

Experimental infection in man and monkey (Cercopithecus callitrichus) by sarcosporidian cysts of cattle and swine]

Reported in this paper is experimental sarcosporidial infection of man and lower primates (grass monkey). The courses of infection were followed up by coprological and serological tests. Oral-alimentary administration of 100 Sarcocystis (S.)-fusiformis cysts obtained from cattle muscle caused patent infection in man. Gastro-intestinal symptoms developed in one of the probands, between five and seven days after infection. No sporocysts were detectable from the stools of seven probands who had consumed 200 g each of commercially available minced pork which contained small amounts of Sarcocystis miescherania villi. Rise in antibody to Sarcocystes following infection was detected however, by means of indirect fluorescence antibody reaction (IFAR). Gastrointestinal complaints were reported by one of the probands, one day after infection. No sporocysts were detectable from the stools of four grass monkeys, following oral-alimentary administration of 50 or 25 S. miescherania cysts, but rise in antibody to S. miescherania was recorded in these cases. Those grass monkeys which had received 50 cysts responded by exhibiting, after infection, severe clinical phenomena with intestinal signs and symptoms of the central nervous sytem.     

The Hen's egg: Factors affecting the shearing strength of shell material

Experiments are described from which it is concluded that

1. the force required to shear egg shell material can be measured with high precision by pressing a narrow, flat‐ended plunger on to the shell;

2. shearing force falls and the precision of its measurement rises as the radius of the plunger is reduced;

3. shearing force is related linearly to shell thickness ;

4. the regression line of shearing force on shell thickness does not pass through the origin but has a substantial positive intercept on the thickness axis, at about a third of the mean thickness ;

5. there are differences between hens and between strains of hen in the magnitude of the intercept, but not in the slope of the regression;

6. shearing force is affected also by the glossiness of the shell;

7. shearing force was not significantly affected by stripped membrane thickness, number of mammillae per unit area of shell, shell organic content (standardised for shell thickness), shell curvature, shell colour, mottling score, translucent patch score, speckling score, age of the egg or age of the hen that laid it;

8. measured with a plunger of radius 165 μm, the mean shearing strength of incremental shell was 57 kg wt/mm² (3–7 ton/in²).

The findings suggest that the shearing strength of egg shells might be increased by direct selection and by selection for shell glossiness.     

Three new Chromadoropsis species (Nematoda,Desmodoridae) from Southern Africa and the North Sea

Three new Chromadoropsis species with four pharyngeal bulbi are described from Southern Africa, Namibia (S.W.A.) and the North Sea. C. granulosus sp.nov. is described from a sandy beach near Port Elizabeth. This species is characterized by a very distinct layer of yellow granules just below the cuticle. C. namibiensis sp.nov. is described from a sandy beach at Langstrand, Namibia. This species can be distinguished by the length and shape of the gubernaculum and spicules as well as the size of the capitulum. C. longispiculosa sp.nov. is described from the North Sea and is characterized by the long spicules and the presence of numerous porids. The genus Chromadoropsis Filipjev, 1918 is revised.     

The Effect of Pneumostrongylus tenuis (Nematoda: Metastrongyloidea) on Kids

Kids, 6-28 weeks of age, infected with 200-1000 infective larvae of meningeal worm (Pneumostrongylus tenuis) of white-tailed deer (Odocoileus virginianus), developed colitis and peritonitis. Bacteroides sp., Bacillus sp., Escherichia coli, Proteus sp. and Enterococcus sp. were found in the peritoneal cavity. Most kids were moribund or dead 4-11 days after infection and frequently the colon had ruptured. Only two kids (of 11) in which the disease was allowed to run its course survived colitis and peritonitis but these two animals developed severe neurologic signs 18 and 38 days after infection. Numerous developing worms and various traumatic and other lesions were found in the central nervous system of kids which developed neurologic signs.     

Ultrastructural observations on the surface of Thelazia lacrymalis (Nematoda: Spirurida, Thelaziidae)

Scanning electron microscopy (SEM) was used to study the surface ultrastructure of female Thelazia lacrymalis obtained from naturally infected cattle. At the anterior end, the buccal capsule was cup shaped. The mouth was without lips and was surrounded by four cephalic papillae and two amphids. There were two lateral cervical papillae. Also, a single small papilla was seen on the ventral side, close to the vulvar opening. The vulva was located posterior to the end of the oesophagus and the tail carried an anal pore and a pair of phasmids near the tip. The cuticle was transversally annulated with fine striations.     

A new species of Trichuris from Thrichomys apereoides (Rodentia: Echimyidae) in Brazil: Morphological and histological studies

Trichuris thrichomysi n. sp., recovered from the cecum of the wild rodent Thrichomys apereoides from a transition zone between the Atlantic Forest and Cerrado morfoclimatic domains, and its life cycle observed under experimental conditions are described. This new species is closely related to Trichuris travassosi, Trichuris chiliensis and Trichuris fulvi, but can be distinguished from them mainly by differences in the posterior end of males. Details of the surface such as the bacillary gland, cuticular inflations and several morphological details obtained by scanning electron microscopy and field emission scanning electron microscopy confirmed the characteristics that differentiate the new species. The histopathology of the intestinal wall of naturally infected rodents is also reported. The present study extends the geographical distribution of T. thrichomysi n. sp to the Pantanal ecosystem and reports a new host, Thrichomys pachiurus.     

First record of Cylicospirura (Cylicospirura) felineus (Chandler, 1925) Sandground, 1933 (Nematoda: Spirocercidae) from a domestic cat in South Africa

Cylicospirura (Cylicospirura) felineus (Chandler, 1925) Sandground, 1933 is reported from a cat in South Africa for the first time. The nematode was present in a gastric parasitic nodule in a male domestic cat, and three males were recovered as well as the anterior parts of three and the posterior parts of two gravid females. The heads of two specimens of undetermined sex were also found. Part of the removed parasitic nodule was processed for histopathological examination. The parasitic nodule was located in the submucosa and slightly expanded into the muscular layer. In its centre were small necrotic areas containing debris of inflammatory cells, adult nematodes and numerous bacterial colonies. Neutrophils, eosinophils, plasma cells and lymphocytes, as well as fibroblasts, were the predominant cell types. The serosal surface of the stomach remained unaffected. Some comparative morphological as well as ecological data concerning Cylicospirura (Cylicospirura) Vevers, 1922 in other feline hosts, mainly from Australia, India and North America, are included.     

Diagnosis and risk factors of Aelurostrongylus abstrusus (Nematoda, Strongylida) infection in cats from Italy

Aelurostrongylus abstrusus (Nematoda, Strongylida) in cats and associated risk factors have been investigated by classical coprology in central (site A) and southern (site B) Italy, i.e. by floatations with sugar and zinc sulphate solutions and a Baermann technique. Overall, 227 individual stool samples (i.e. 162 from site A and 65 from site B) were processed and risk factors were related to infection by binary logistic multiple-regression models. The presence of A. abstrusus was used as the dependent variable and the epidemiological data as independent variables. Twenty-eight (17.3%) and 12 (18.5%) cats were positive for A. abstrusus in sites A and B, respectively, both using the Baermann and flotation with zinc sulphate solution methods. Six and three (from site A and B, respectively) of the infected cats were negative for A. abstrusus when faeces were processed with sugar solution. Stray and free-ranging (P=0.357), young cats (P=0.008) and the presence of respiratory symptoms (P=0.000) were risk factors for A. abstrusus infection. The results suggest that A. abstrusus is spread in Italy. Furthermore, these results possibly include infection in the differential diagnosis of feline respiratory diseases and offer a correct diagnostic approach by using either a Baermann method or flotation with zinc sulphate solution in suspected cases.     

The hen's egg: Effect of a hole in the shell on the incidence of splitting during cooking

Two experiments, involving nearly 1000 eggs, were designed to show whether or not piercing the shell at the broad pole prevents it splitting when an egg is soft‐boiled. With eggs stored in the laboratory the incidence of splitting was low after storage for 1 d and there was no indication that the presence of a hole affected it; after 5 d splitting was reduced; after 28 d it was prevented. This may be because at 1 d the shell is still permeable, so even if there is no hole the build‐up of internal pressure as the egg contents expand is limited; at 5 d, when shell permeability has fallen, pressure build‐up is prevented initially by the presence of a hole, though it can occur in the later stages of cooking because the hole becomes sealed by congealed albumen; at 28 d the hole remains patent and the air space can accommodate all the expansion of the egg contents. The nature of the hole, whether made by piercing with a needle or by drilling to 1·5 mm diameter with a dental drill, did not significantly affect the response of eggs of any age.

Housewives should pierce eggs before boiling them, since if they are fresh it will do no harm and if they are stale it will prevent splitting.     

Eustrongylides sp. (Nematoda: Dioctophymatoidea) from the stomach of a Nile crocodile, Crocodylus niloticus Laurenti, 1768, in Botswana

During a study conducted between 2003 and 2005 on the diet of Nile crocodiles in Botswana, two young adult nematodes, one male and one female, belonging to the genus Eustrongylides J?gerski?ld, 1909 were recovered from the stomach contents of one of these animals. The caudal bursa of the male is present and the ejaculatory duct could be identified, but the spicule could not be seen. The vulva of the female has opened and the anus is situated on a terminal protruberance. Measurements and drawings of these specimens are provided, together with some data on the occurrence and life-cycles of members of the genus Eustrongylides in crocodilians world-wide and in African hosts in particular. Piscivorous birds are the usual final hosts of these nematodes. It is probable that the specimens described herein had developed in a paratenic fish host, and that the latter had been eaten by the crocodile.     

The systematic position of some Ethiopian Nippostrongylinae (Nematoda, Trichostrongylina, Heligmosomoidea) from the National Collection of Animal Helminths, Onderstepoort, South Africa

The taxonomic status of some nippostrongyline nematodes deposited in the National Collection of Animal Helminths, Onderstepoort, is revised. Heligmonina boomkeri n. sp. is described from Aethomys chrysophilus from South Africa. The most closely related species by the body measurements and the pattern of the caudal bursa is Heligmonina bignonensis Diouf, Ba & Durette-Desset, 1997, a parasite of Mastomys erythroleucus from Senegal. It differs from the new species mainly in the number of ventral cuticular ridges at mid-body (four versus five) and the left ala in the male is shorter than the body diameter. The systematic position of Heligmonina spira (Ortlepp, 1939) and Neoheligmonella capensis (Ortlepp, 1939) is confirmed here through their synlophe, which was not previously studied.     

A Counter-Current Heat Exchange System in the Tail of the Vervet Monkey,Cercopithecus Pygerythrus (Primata : Cercopithecidae)

Lightly anaesthetized vervet monkeys can maintain their body core-temperature by skin vasoconstriction and shivering when the environmental temperature is moderately lowered.

Under such conditions the arterial blood supplying the tail skin is several degrees cooler than the core temperature and thus heat loss from the tail is reduced.

The core-caudal artery temperature difference is most probably due to counter-current heat exchange between the median sacral and caudal artery and the median caudal veins above the sixth postsacral tail segment.

The medial caudal veins are small compared with the dorsolateral caudal veins which run a superficial course, but the arrangement of valves permits movement of blood between them. The balance of blood flow in the two systems will determine the extent of heat exchange with the arterial inflow. The properties of the dorsolateral veins and the structural arrangements increase the proportion of blood returning by the median system under cool conditions.

The functional integrity of the sympathetic nervous system is necessary for effective control of the heat exchange system.     

The Hen's egg: Variation in tensile strength of shell material and its relationship with shearing strength

The tensile strength of egg‐shell material is believed to play an important role in determining whether or not a shell will crack when exposed to an environmental insult. Experiments are described in which shell tensile strength was measured. It is concluded that:

1. the force required to produce tensile failure did not vary linearly with the width of the piece of shell under test, but with its two‐thirds power;

2. it varied linearly with the thickness of the shell;

3. the line relating force at tensile failure to shell thickness did not pass through the origin but intercepted the thickness axis at between about 90 and 130 μm, indicating that the inner layers of a shell, up to about a third of its thickness, contributed little or nothing to its tensile strength;

4. the slope of the line did not vary with hen or strain of hen, indicating that the shells did not differ in the tensile strength of the material constituting their outer layers (i.e. about the outer two‐thirds);

5. there were differences between hens and strains in the magnitude of the intercept: shells of the same thickness but from different hens or strains differed in force at tensile failure;

6. the existence of between‐strain differences in intercept constitutes prima facie evidence that the variation in this trait is under genetic control;

7. there was a fairly large within‐egg residual component of the variance of force at tensile failure; it represents real variation in tensile strength between apparently similar pieces of the same shell and is believed to be an effect of chance in the distribution of flaws in the shell material;

8. for any one hen the intercept is the same as that found when shearing strength is measured, so shearing strength (which can be determined easily, quickly and precisely) can be used as a predictor of tensile strength.

Implications for poultry breeders are discussed; it is suggested that they should select for shell strength instead of shell thickness, measuring strength as shearing strength.     

Oncholaimus jessicae n.sp. (Nematoda: Oncholaimidae) from fresh water in the Transvaal

Oncholaimus jessicae n.sp. is described from several sites in the Blyde River system in the eastern Transvaal. The new species closely resembles O. deconincki Heyns & Coomans, 1977, from which it differs mainly in the absence of males and details of the demanian system: the ductus entericus is much longer, the uvette is situated closer to the anus, and the main duct is better developed and glandular.