SAFETY STUDIES WITH BROILERS ‘TOE ASH AND BLOOD SERUM COMPONENTS“
Supplementing Improved Milbond-TX® (IMTX) to broiler diets at higher than the recommended concentration of 0.25% (2.5g/kg diet) has been reported to be safe and no detrimental effects on broiler performance have occurred even when diets containing up to 2.0% IMTX are fed . This was confirmed in two experiments by researchers at the University of Florida (Miles and Henry, 2007) when they reported that feeding IMTX in the diet of broilers at concentrations up to 2.0% did not have any detrimental effect on broiler performance as measured by body weight, feed consumption, feed conversion and excreta moisture. Also, in these experiments, the authors collected data on percent toe ash and components of serum chemistry in their birds at the end of the 21 day experimental period. In broilers fed diets containing up to 2.0% IMTX the percent toe ash and components of serum chemistry were no different than those for the control broilers fed diets containing no IMTX.
Miles and Henry (2007) selected toe ash as the wellestablished method of determining bone mineralization rather than tibia ash because of the simplicity of toe collection and preparation compared with that required for bone ash. Hence, no ether extraction or removal of flesh tissue is required when using toe ash as the measure of bone mineralization. At the end of the 21–day experimental period for each experiment all chicks were killed and the middle toes of each chick were removed at the tarsometatarsal/P3 joint with the skin intact. The tip of the toe containing the nail was removed and discarded, and then the toes were cleaned of any adhering foreign material with a wet paper towel and pooled by pen for toe ash analysis. Each set of toes was dried in an oven for 48 hours at 1 oo·c. then ashed in a muffle furnace at 550‘C for 14 hours to determine the toe ash weight (see figure).
Bone mineralization was of special importance in these experiments in which high dietary concentrations of IMTX were fed to broilers since Aluminum (Al) is one factor that has a profound negative effect on bone mineralization and IMTX contains from 145 to 197 g Al20 3. (100 to 136 g/kg Al) /kg. It is well established that Al complexes with P in the gastrointestinal tract of animals and reduces the relative bioavailability of P. If the Al in the IMTX complexed with P in the gastrointestinal tract and prevented absorption and utilization of Pin bone formation , then a decrease in serum P and toe ash would be expected. This would be especially true with the highest concentration of IMTX in the diet. These negative effects were not observed in these experiments discussed by Miles and Henry (2007).
BLOOD SERUM COMPONENTS
In the in-vivo study reported by Ledoux et al. (1999) serum chemistry profile was of major concern since their broilers were being fed diets containing 4 mg/kg Aflatoxin B1 with and without IMTX at a dietary concentration of 1 %. When the serum chemistry values for Ca, P, Na, Cl, total protein, cholesterol, glucose, albumin and globulin, in the chicks fed IMTX with no Aflatoxin B1, were compared to values for chicks fed the control diet also containing noAflatoxin B1, similar values existed. Also, IMTX was shown in these experiments to be 100% effective in removing the negative effects on broiler performance of feeding diets containing 4 mg/kg Aflatoxin B1 . In addition, except for glucose and cholesterol, IMTX restored back to control diet values the serum chemistry profile values of chicks fed the diet containing the combination of Aflatoxin B1/IMTX. Thus, these authors were able to demonstrate that IMTX fed at a dietary concentration of 1.0% was totally safe to broiler performance and also completely removed the negative effects in broilers fed diets containing 4 mg/kg Aflatoxin B1.
In the IMTX safety experiments reported by Miles and Henry (2007)the serum chemistry values for Ca, P, Na, Cl, K, total protein, triglycerides, cholesterol, glucose, albumin and uric acid in control birds fed no IMTX were no different than those from broilers fed diets containing IMTX at a concentration of 2.0%. The dietary concentration of IMTX used by these investigators was twice the concentration used in the study reported by Ledoux et al. (1999) in which they also reported no detrimental effect on broiler performance of feeding IMTX at a dietary concentration of 1.0%.
The studies reported here which were conducted at the University of Florida (USA) and the University of Missouri (USA)clearly demonstrate that when IMTX is fed to broilers at a dietary concentration that is eight times greater than the recommended concentration of 0.25%, birds performed the same as when fed diets containing no IMTX. This is not surprising since IMTX is inert and not expected to affect animal performance.