Effects of low-level dietary deoxynivalenol on haematological and clinical parameters of the pig.

The subacute toxic effects of dietary deoxynivalenol (DON) were examined in grower pigs during a 32 day feeding period. DON was incorporated into the feed at 0, 1, and 3 mg/kg, added as either the purified toxin (P) or as naturally contaminated corn (N). Growth performance and blood biochemical and haematological parameters were monitored throughout the study. At the higher toxin levels (diets 3P, 3N) significantly lower feed consumption and body weight gains were evident soon after the start of feeding, but while weight gains of pigs fed the pure DON diet (3P) recovered after several days, values for pigs fed the naturally contaminated diet (3N) remained depressed over the course of the study. It is possible that these observations reflected the presence of other unidentified toxic compounds in the naturally contaminated grain. Generally, blood chemistry parameters of pigs fed the contaminated diets were not different from controls, with the exception of alpha-globulin and possibly cortisol in animals receiving diets 3N or 3P. Data suggested that the effect of DON on the alpha-globulin fraction may have been independent of the feed refusal syndrome associated with this toxin. Alterations in several haematological measurements were noted to occur sporadically with the 3 ppm diets, including higher RBC count, haematocrit and platelet level, however these effects could not be separated from the influence of decreased feed intake and were of limited value in diagnosing the effects of low level dietary DON on swine.

Selecting the size of a diallel cross experiment.

The size of a diallel cross experiment can be determined by using statistical tables and past diallel cross results; this will provide more flexibility in planning experiments and increase the opportunity to detect real differences.

Rumen ciliate protozoa: effects on digestion in the stomach of sheep.

Six wethers, each fitted with a rumen cannula and duodenal reentrant cannula, were used to study effects of ciliate protozoa on rumen digestion and metabolism. A corn: corn silage (1:1) diet was fed for two periods. During the first period, defaunation was attempted with nonyl phenol ethylene oxide. Defaunation was complete in three sheep and partial in the other three sheep in which a reduced population of a small Entodinium sp. was observed. During the second period the sheep were inoculated with ciliate protozoa, which established a large population in all animals. Apparent digestion in the stomach of organic matter and starch was higher when a large protozoal population was present. Amino acid flow through the duodenum was greater in defaunated animals. A large population of ciliates was associated with increases in both rumen ammonia and plasma urea but had a stabilizing effect on ruminal pH. Volatile fatty acids were higher in the defaunation period, but there were only small differences of molar proportions of the acids between the two periods. Effects of ciliate protozoa are related to animal performance.