2002 National ASAS meeting

Reducing odor in swine production:

Effect of a natural carbon-mineral supplement on odor reduction

Kim, S. W., F. Ji, and J. J. McGlone

Texas Tech University

A natural, carbon-mineral source (NCM) is a feed supplement that is mined and minimally processed (Promax^®, HumaTech, Inc., Houston, TX). Carbon compounds include humic acid, fulvic acid, and other organic compounds and minerals include bioavailable iron and other trace minerals. Use of NCM in swine diets is a relatively new concept. Ninety-six pigs, weaned at d 21 of age, were used to determine the effect of NCM supplementation to a swine diet on odor reduction. Pigs were allotted to one of two treatments, control group and NCM group. Each treatment had six replicates and a group of eight pigs was housed to each pen-replicate. The NCM was supplemented to the treatment diet at the level of 0.5%, but it was not supplemented to the control diet. After weaning, pigs were fed based on a 3-phase feeding program. Phase 1 was one week postweaning, phase 2 was two weeks after phase 1, and phase 3 was four weeks after phase 2. A group of eight pigs from each pen-replicate was moved to a pen (1.2 x 2.4 m) in a ventilated environmental chamber (3.0 x 3.0 x 2.4 m) for two d during which aerial ammonia was measured. The temperature inside of the chamber was maintained at 24 C and the fan was working continuously during the experimental period. A gas monitor with the sensors for ammonia, and hydrogen sulfide was used to measure the changes of these compounds during the 2 d collection period with 5 min intervals. Feed intake of pigs during the 2 d collection period was measured. The initial and final body weights were measured before and after moving pigs to the chamber. Feed intake and initial body weight were used as co-variables in analyzing the data. In data analysis, the first 24 hr period was considered an acclimation period and the data from the last 24 hr period was considered the primary data collection period. Hydrogen sulfide was very low and generally not detectable in our model. The main effect of treatment was not significant (P > 0.10). The treatment by time interaction, however, was highly significant (P < 0.0001). Pigs given dietary NCM produced 5 to 40% less air ammonia. The regression models calculated from the raw data showed a clear diurnal variation in air ammonia. The increase in ammonia was associated with pig activity and low air ammonia was found when pigs were less active. Pig activity probably increased air ammonia by both producing more ammonia through more excretions and by mixing the air more when pigs were active. Using our model system, this formulation of NCM may reduce air ammonia to different degrees depending upon the time of day and pig activity levels.

Key Word: Pigs, Natural carbon mineral, Odor