Introduction

The Author

Dr. Susan Watkins Extension Poultry Specialist

While the manufacturers of these products provide mixing instructions, there is no guarantee of the final water pH mainly because of the broad diversity of water pH found in nature. A report from North Carolina State University several years ago claimed that a water pH of less than 5.9 was harmful to bird performance (Carter, 1987).

However this report was based on field observations where unknown factors other than naturally low water pH could have contributed to the poor performance. Low pH water is aggressive and can actually dissolve metal pipes releasing lead, copper and other minerals into the water. While the use of PVC pipes minimizes the concern of mineral leaching, the question still remains. Which water pH level is optimum for broiler performance?

Therefore, two trials were conducted to study the impact of different water pHs on broiler weight gains, feed conversion, water consumption and livability. In addition, this experiment addressed adjusting the water pH on a continuous or intermittent basis to determine if this could also have an impact on performance.

Trial One

Trial one was conducted during the summer months when the outside daily temperatures exceeded 90° F, particularly late in the grow-out cycle. The effects of heat stress were reduced through the utilization of tunnel ventilation and spray on fogger pads.

Twelve hundred male broiler chicks were randomly placed into 24 floor pens to give 50 birds per pen at a density of .85 square feed per bird. There were three pens per treatment. Each pen was equipped with two hanging tube feeders and one Val nipple drinker line complete with regulator and six nipple drinkers. Flow was adjusted weekly to provide the milliliters/ week of age recommended by Lott et al. (2003).

The formula for determining rates added 7 ml/week of age plus 20 ml, so that, for example, a 21 day old broiler received 3 x 7=21 ml plus 20 for a total of 41 ml. Each pen had its own water supply via a 5- gallon poly-bucket reservoir. Table 1 denotes the treatments. PWT®, which is sodium bisulfate, was used to adjust the pH. Fayetteville, Arkansas municipal drinking water was used as the control and the average initial pH was 8.3. All water and feed added to the pens was weighed. Birds received diets formulated to meet their nutrient requirements. In Trial one, Coban® was used for coccidiosis control. Also the growth promoter BMD was used in all the feeds.

Trial Two

Trial two was conducted during January and February when outside daily temperatures ranged from 10 to 45° F. In this trial, two thousand male broiler chicks were randomly placed in 40 floor pens to give five pens per treatment. Four replicate pens per treatment were equipped with nipple drinker lines and the water added to these pens was measured for the determination of water usage.

A fifth replicate pen per treatment was equipped with a Plasson drinker. Water consumption was not measured in the pens with the Plasson drinkers. As in trial one each pen had its own water supply via a 5-gallon poly bucket reservoir and two hanging tube feeders.

Treatments were identical to trial one with PWT® used to adjust the pH. All feed added to the pens was weighed for determining feed conversion. Birds received the same diets as in trial one. In this trial, the coccidiostat Sacox® was used. No growth promoting antibiotic products were used. At day forty-two, 10 birds per treatment were killed with carbon dioxide gas and the pH of the crop and gizzard contents was determined.

Both Trials

In both trials the birds were group weighed by pen at day 1 and on days 7, 21, 35 and 42. On day 42 birds were individually weighed. Feed and water consumption were determined for each of these time periods. Water usage was measured at each feed change.

Results

The results for the two trials were combined because there were no differences in the way birds responded to the treatments for the two trials. The average weights of the broilers for the different ages evaluated are shown in Table 2.

The statistical analysis indicates that while there may be slight numerical differences in the average weights of the broilers receiving the different treatments, there was no advantage or disadvantage for the broilers receiving different pH drinking water as compared to birds receiving the control water. The closer the P value is to one, the more statistically similar the results.

Table 3 shows the average feed conversions (adjusted to account for the weight of the dead birds). Cumulative feed conversions for days 7, 21 and 35 were not statistically different. The feed conversions at day 42 show birds on the continuous 4 and 5 pH water and the intermittent 3 and 4 pH water had the numerically best feed conversions. However, the conversions were statistically similar to the conversions for broilers receiving the control water. Water usage as shown by milliliters of water used per gram of gain showed that the birds used similar amounts of water regardless of drinking water pH (Table 4).

When the crops and gizzards of birds receiving the different pH water were tested for pH, it was found that the birds receiving the pH 3, 4 and 5 water had a significantly lower crop pH than birds receiving the 6 and control pH water (Table 5). No difference was found in the gizzard pH and this would be expected since the bird adds hydrochloric acid to the digestion process.

Comments and Conclusions

This research project found no significant improvement in average weights, feed conversion or water consumption when the drinking water pH was lowered to 3, 4 or 5. The results indicate that birds are very tolerant of a wide range of pH water. The findings that the crop pH was significantly lowered by reducing the water pH might explain why producers have reported that bird droppings become more firm when acidifiers are added to the water. The crop serves as a storage compartment for consumed particles.

Nature designed the crop to store whole bugs and seeds, not the finely ground, easily digested feed utilized by broilers for efficient feed conversions. If the crop is full of feed and poor quality water is added, then there is an increased risk for the development of harmful bacterial and mold that could impact the rest of the digestive tract. However, research done in Alabama by Hardin and Roney (no date) found that a pH range of 4 was not favorable for bacteria such as E. coli, Salmonella and Clostridium to grow and thrive.

The current research indicates that it is possible to decrease the drinking water pH to a range that would lower the crop pH to almost 4, thus creating an environment that is hostile for undesirable microbes. However, given the diversity of drinking water sources it is a very good idea to measure the pH of the drinking water when using acidifiers at manufacturer’s recommendations because the natural buffering capacity of water may result in reduced impact of the acidifier on pH. It may even be necessary to add more acidifier to the stock solution to achieve a lower drinking water pH.

References

Carter, Thomas. 1987. Drinking Water Quality for Poultry, Poultry Science and Technology Guide No. 42, Extension Poultry Science, North Carolina University.

Hardin, Boyd and C.S. Roney. No Date. Effects of pH on Selected Poultry Bacterial Pathogens, Alabama Department of Agriculture and Industries State Diagnostic Lab.

Lott, B. D., W. A. Dozier, J. D. Simmons and W. B. Roush. 2003. Water flow rates in commercial broiler houses. Poultry Sci. 82 (Suppl. 1):102.