Towards Efficient Early Warning: Pathobiology of African Swine Fever Virus “Belgium 2018/1” in Domestic Pigs of Different Age Classes

African swine fever (ASF) is one of the most important and devastating viral diseases in wild boar and domestic pigs worldwide. In the absence of vaccines or treatment options, early clinical detection is crucial and requires a sound knowledge of disease characteristics. To provide practitioners and state veterinarians with detailed information, the objective of the present study was to characterize the ASF virus (ASFV) isolate “Belgium 2018/1” in subadult and weaning domestic pigs. To this end, two animal trials were performed. Trial A included eight subadult domestic pigs and trial B five weaner pigs. In general, clinical signs and pathological lesions were in line with previous studies utilizing highly virulent ASF genotype II viruses. However, in trial A, four subadult domestic pigs survived and recovered, pointing to an age-dependent outcome. The long-term fate of these survivors remains under discussion and would need further investigation.

Weight Gains and Economy of Production of Weaner Pigs Fed Diets Containing Fermented Mixture of Cassava Root Pulp and Palm Kernel Cake as Replacement for Maize

The need to improve the nutritive value of feed materials containing high levels of non-starch polysaccharides (NSPs) such as lignin, cellulose, mannan among others for monogastric feeding has led to interest in solid state fermentation (SSF) in recent years. In this study, the efficacy of SSF to improve nutritive value of mixture of grated cassava roots and palm kernel cake for pig feeding was evaluated using 40 unsexed crossbred (Large White X Nigerian Indigenous) weaner pigs. The pigs were randomly allotted to five treatment groups and fed experimental diets in which the maize in the control diet was partially (50%) or completely replaced with either solid state fermented mixture of grated cassava root and palm kernel cake (FEMCARPP) or a 1:1 blend of cassava meal and palm kernel cake (CSM-PKC). Data was collected weekly on the live-weight, weight gain, feed intake and feed conversion ratio, and efficiency of protein utilization. The pigs on dietary FEMCARPP consumed significantly (p < 0.05) less feed but had superior weight gain and similar feed conversion ratio when compared to the control pigs fed maize based diets. In addition, pigs fed dietary CSM-PKC consumed significantly (p < 0.05) more feed and were less efficient in utilizing their feed. It is therefore concluded that solid state fermentation improved the nutritive value of mixture of grated cassava roots and palm kernel cake for swine feeding. Further research is however needed to extend the study to growing-finisher phase and to understand the physiological mechanism of the improved performance of the piglets on dietary FERMCAPP.

PSV-19 Effect of Low Nutrient Density Diet with Probiotic Mixture (B. Subtilis ms1, B. Licheniformis SF5-1, and S. Cerevisiae) Supplementation on Performance of Weaner Pigs

BACKGROUND: A total of one hundred and forty, 28 d-old weaner pigs [Duroc x (Yorkshire x Landrace)] with initial body weight (BW) of 6.56±1.25kg were used in a six-week treatment (7 replicate pens per treatment; barrows, and 2 gilts/pen) to evaluate the effect of low nutrient density diet supplement with probiotic mixture supplementation on the growth performance, nutrient digestibility, fecal microbial, and gas emission of weaner pigs. RESULTS: Pigs fed low-density diet with probiotic mixture supplementation had linearly increased (P = 0.028, 0.014) the body weight (BW) at weeks 3, and 6. Moreover, average daily gain (ADG) was linearly improved (P=0.018, 0.014, 0.014) at week 3, 6, and overall experiment. However, there were no interactive effects found on the nutrient digestibility of dry matter (DM), nitrogen (N) and energy (E) throughout the experiment. Dietary inclusion of low-density diet with probiotic mixture supplementation has improved the fecal lactobacillus counts linearly, but E. coli was unaffected during the trail. On day 42, Ammonium gas emission was significantly decrease in pigs fed a low-density diet with probiotic mixture supplementation. However, H2S, acetic acid, and CO2 were not significantly affected by the probiotic mixture supplementation diet. CONCLUSION: Low-density diet with probiotic mixture supplementation had positively affected the growth performance, fecal microbial, and fecal gas emission on weaner pigs.

The Effect of Colistin Treatment on the Selection of Colistin-Resistant Escherichia coli in Weaner Pigs

The treatment of diarrhea in the postweaning period is a common reason for the use of antimicrobials in pig production, and Escherichia coli is the single most important causative agent for this condition. Colistin has recently been classified as a critically important antimicrobial for human health, as it is a last-resort drug against certain multi-drug-resistant Gram-negative bacteria. Therefore, the use of colistin has been significantly reduced in some countries, including Denmark. Despite this, the drug is still commonly used to treat diarrhea in pigs in many countries, and there is a need to understand the risks associated with this practice. We performed a prospective cohort study to investigate the effect of colistin treatment on the changes in the average minimum inhibitory concentration (MIC) in commensal E. coli in a pig herd where no colistin-resistant bacteria were detectable before treatment. One group of pigs was batch treated with colistin after the clinical observation of diarrhea, one group was batch treated with colistin approximately 10 days before the expected onset of diarrhea, and a control group was not treated with colistin but provided with nonantimicrobial antidiarrheal feed supplement. Treatment with colistin in the dose and time combinations used did not result in a significant increase in the average colistin MIC values in E. coli. Moreover, no E. coli strains showed a MIC above the breakpoint of >2 mg/L against colistin. Co-selection of resistance to other antimicrobials was not observed.