The Comparative Value of Antibiotics and Arsonic Acids for Growing Pigs

Abstract
One hundred and sixty purebred pigs were fed in 4 trials of 8 ration treatments with 5 pigs per lot. Chlortetracycline (Aureomycin), procaine penicillin, erythromycin, arsanilic acid and 3-nitro-4-hydroxyphenylarsonic acid were compared with each other and with a combination of arsanilic acid and chlortetracycline and with arsanilic acid and procaine penicillin. In 3 of the 4 trials the daily live weight gains of the pigs fed chlortetracycline, procaine penicillin or the combination of either antibiotic with arsanilic acid exceeded the gains of the control pigs. None of the differences between treatments was significant at the 5 percent level. The pigs fed chlortetracycline had the largest and most consistent superiority over the control group in feed efficiency, but this amounted to only 5 percent. The lack of a significant response to antibiotics or arsonic acids is attributed to the generally high quality of pigs fed in this experiment. Arsenic assays of tissues of pigs fed arsonic acids alone or in combination with antibiotics showed that arsenic retention was related to the level of arsenic fed. This confirms the previous findings at this Station. There was no evidence of toxicity in any of the pigs fed arsonic acids.