Leucomycin (Leucomag 30% PR), former known as Kitasamycin, produced by Streptomyces kitasatoensis (VEZINA et al.
The three treatments were: no feed medication (T1); 90 ppm of leucomycin (T2); and 180ppm of leucomycin (T3) feed inclusion.
Eleven pigs, one from non-medicated group (T1), seven from the group medicated with 90ppm of leucomycin (T2) and three medicated with 180ppm of the same antibiotic (T3) died or had to be euthanized the day after inoculation due to inoculum aspiration (aspiration pneumonia) or paraesophageal fistula and pleuritis caused by the probe during inoculation.
Other two pigs, one from non-medicated group (T1), 18 days pi, and the other from the group medicated with 90ppm of leucomycin (T2), 22 days pi, died.
The ADG difference between medicated and non-medicated groups demonstrated the positive effect of leucomycin (Table 1).
A well-established challenge model was used in order to test the positive effect of leucomycin in controlling PPE (WINKELMAN et al.
In this study, already on day 13pi, animals medicated with 180ppm (T3) of leucomycin were heavier and had better ADG than the non-medicated group (T1) (P<0.
The efficacy of leucomycin was expected due to prior empirical findings in commercial farms and to the properties of other molecules in the pharmacological group.
Under the conditions of this study, leucomycin administered in feed at 90 and 180ppm for 14 consecutive days, beginning just before challenge, improved ADG, ADFC and FCR in treated pigs compared to unmedicated challenged controls.
The patents issued are: Number 6,436, 906, titled "9-Amino-14-Membered Macrolides Derived from Leucomycins
," Number 6,440,942, titled "14-Membered Macrolides Derived from Leucomycins
," and Number 6,462,026, titled "Bicyclic Leucomycins