Intestinal Protozoa of the African Elephant Loxodonta Africana (Blumenbach)

The digestive tract of 15 elephants from South Africa and two from Zaïre were sampled in order to determine the identity, density and population composition of the intestinal protozoa. The following orders were represented: Gymnostomatida, Trichostomatida and Entodiniomorphida. Altogether 17 species were identified, of which three are new. The new species as well as a new genus are described.     

Multiple births in Schlieffen's bat,Nycticeius schlieffenii (Peters, 1859) (Chiroptera: Vespertilionidae) from the southern African subregion

Nycticeius schlieffenii is a monestrous species that breeds during the spring months in the northern parts of the Kruger National Park. During spring 1983 the average number of corpora lutea in 11 Nycticeius schlieffenii females was 3,1 (range 1 -4), with the average number of fetuses recorded 2,8. In the present study this bat has been found to be a polyovular seasonal breeder, giving birth to as many as three young per estrous cycle.     

Sessile peritrichs (Ciliophora: Peritricha) from freshwater fish in the Transvaal,South Africa

Sessile peritrichs (Ciliophora: Peritricha) were collected from freshwater fish in lakes, rivers, streams and fish-ponds in the Transvaal, South Africa Nine species of the genus Apiosoma Blanchard, 1885 are described, i.e. seven new species; A. caulata sp.n., A. curvinucleata sp.n, A. micralesti sp.n., A. mothlapitsis sp.n., A. obliqua sp.n., A. phiala sp.n. and A. viridis sp.n., and two known species; A. nasal is (Timofeev, 1962) and A. piscícola Blanchard, 1885. One new species of the genus Ambiphrya Baabe, 1952 is described, i.e. A. neobolae sp.n. A new sgenus, Scopulata gen.n. is proposed for species with a broad scopula and compact macronucleus. Two previously described Scyphidia species are incorporated in this genus, i.e. S. dermata (Viljoen & Van As, 1983) comb.n. and S. epibranchialis (Viljoen & Van As, 1983) comb.n., as well as a new species, S. constricta sp.n. Compendiums of all the known fish-associated species of these genera are provided.     

The effect of cat Felis catus predation on three breeding Procellariidae species on Marion Island

Breeding success of Pterodroma macroptera, Procellaria aequinoctialis and Pachyptila vittata salvini in three cat-free and three control areas were used to evaluate the effects of cat Felis catus predation on the avifauna of Marion Island. Breeding success of all three species was significantly higher in the combined cat-free areas than in the combined control areas. However, breeding success in one cat-free area failed to show a significant difference from its particular control area, probably as a result of higher skua (Catharacta antarctica) predation inside the cat-free area. Chicks of P. macroptera and P. aequinoctialis were especially vulnerable to cat predation, since cats can enter their nesting burrows. P. macroptera was seriously affected by cat predation because it is the most abundant of only two winter-breeding petrels. Significant changes in the number of nest visits by these petrels during their breeding season followed hatching dates, which in turn were concomitant with, or were followed by significant differences in the combined breeding success between the cat-free and control areas. The cat-free areas show that an elimination of cat predation would still favour the recovery of the petrel population.     

Observations on the attachment of a piscine gill parasitic ergasilid (Crustacea: Copepoda)

The attachment of the piscine gill parasite, Ergasilus mirabilis Oldewage & van As, 1987 is described by means of scanning electron microscopy and light microscopy. A variety of sensory structures occur on and around the host contact surface of the parasite and proliferation of gill tissue occurs at the site of attachment. It would appear that this proliferation of host tissue results from the feeding behaviour of the parasite rather than the actual attachment thereof.     

Virulence of five live vaccines against Avian Infectious Laryngotracheitis and their immunogenicity and spread after eyedrop or spray application

Summary

Five live virus vaccines against avian infectious laryngotracheitis were studied with regard to safety, immunogenicity and route of administration. Significant differences in virulence between the vaccine strains were found. Reduced virulence was accompanied by a reduction of immunogenicity and capacity to spread.

After eyedrop application, a low virulent vaccine induced 90‐ 100% flock immunity for the first 10 weeks after vaccination (PV), followed by a slow decline to 50% at 31 weeks PV, whereas flock immunity induced with the more virulent types remained at about 90% till the end of the experiments (24 and 48 weeks PV).

Aerosol vaccination induced 70 ‐ 100% flock immunity but vaccine reactions were severe. Application of vaccine in a coarse spray did not result in adverse vaccine reactions but induced a maximal protection rate of only 50%.

Microneutralisation titres provided a useful indicator of immunity from the onset of immunity until immunity started to decline. A vaccine virus carrier state was demonstrated by means of sentinel birds.     

Bilirubin metabolism in canine hepatobiliary and haemolytic disease

Summary

The kinetics of unconjugated ₃H‐bilirubin are described in 25 healthy dogs and 35 dogs with spontaneous hepatobiliary or haemolytic disease, using a two‐compartment model. The bilirubin production rates from erythrocyte degradation (P_E), ineffective erythropoiesis (P_I) and catabolism of hepatic haemoproteins (P_I), were derived from the incorporation of ¹⁴C‐glycine into haemoglobin and stercobilin. These combined measurements permitted an integral survey of bilirubin metabolism in health and disease. The concentration of unconjugated bilirubin in plasma and its of total bilirubin levels were similar in hepatic and haemolytic disorders.

This was explained by the highly increased bilirubin production rates in both types of disease. In addition, the hepatic bilirubin clearance was severely impaired in fulminant hepatitis and in cirrhosis, and moderately decreased in the other hepatobiliary diseases and in primary haemolysis. The erythrocyte lifespan was reduced in all animals but one. In addition to haemolysis, the contribution of P_I and P_L was variable, and in two dogs P_L was the principle source of highly increased bilirubin production rates. These data indicate that the concentration of unconjugated bilirubin in plasma or its fraction of total pigments is unreliable in the discrimination of canine hepatobiliary disease from haemolytic disorders.     

Mortality,morbidity, and external injuries in piglets housed in two different housing systems

An investigation was undertaken to study two different types of farrowing pens, use being made of well characterized veterinary parameters for the well‐being of piglets. A housing system with a solid floor and straw‐bedding was compared with a partly metal‐slatted floor system. The veterinary parameters we used were mortality, morbidity, and external injuries in piglets. There were slight differences in mortality and morbidity rates between the two housing systems. There were big differences with regard tp the piglets” injury‐index’ of the two housing systems. The straw system was more favourable. The studies show that obervations of external injuries ('Method of Ekesbo') can be used to judge housing systems of piglets in the farrowing house.     

The interaction between plant lectins and the small intestinal epithelium: A primary cause of intestinal disturbance

Summary

The literature concerning the effects of plant lectins on the small intestinal epithelium is reviewed. It appears that after oral intake, intact plant lectins can reach the small intestinal lumen. Their binding to the mucosal surface evokes an increased synthesis of glycoproteins and a degeneration of the intestinal epithelium. The epithelial alterations may result in hyperregenerative villus atrophy and endogenous nitrogen loss. These changes ultimately can lead to less efficient feed conversion, diminished growth, scouring, wasting and death. The possible significance of plant lectins in digestive disturbances in farm animals is suggested.