Submitted to: Poultry Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/4/2005
Publication Date: 3/1/2006
Citation: Rath, N.C., Huff, W.E., Huff, G.R. 2006. Effects of humic acid on broiler chickens. Poultry Science. 85:410-414. Interpretive Summary: Humic acid is a soil component formed from decomposed leaves, woods, and other organic matter; therefore, can occur in ground water. Some human bone problems have been linked to humic acid. The water supply in many poultry farms is from ground wells. Therefore, we wanted to find if humic acid was involved in the cause of poultry leg problems. To find this we fed chickens with humic acid added to their diets for 4 and 5 week period and examined their bone and checked the status of their health with different clinical measurements. Humic acid only reduced the growth of chickens but had no other toxic health effects or bone problems.
Technical Abstract: In view of the alleged effect of humic acid (HA) on growth plate arthrosis in humans, we sought to find if poultry tibial dyschondroplasia (TD) is caused by HA that can occur as ground water contaminant. In two separate trials, broiler chickens were fed different concentrations of HA added to their diet for 4 and 5 wk respectively. The effects of these treatments was measured by general health indices such as growth, feed conversion ratio (FCR), relative organ weights, blood differential count, serum chemistry, TD index, and bone biomechanical strength. Humic acid treatment decreased BW, but appeared to improve FCR. There was no effect on TD index or bone biomechanical strength in HA treated birds compared with controls. There was no toxic effect of HA which was evident by the absence of any dramatic change in relative organ weights, or other telltale signs of serum clinical chemistry that would suggest liver, muscle, or kidney dysfunction. While RBC, WBC, monocyte, and hematocrit values were not affected but there was a decrease in blood heterophil counts and heterophil to lymphocyte ratio which was significant in 4 wk HA-treated birds. Overall these results show that while HA slows down growth it does not have any adverse health effects on chickens.