Research Summary on the Effects of

Lactose in Poultry Diets

Dustin Dean, Ph.D. and Kevin Halpin, Ph.D.

International Ingredient Corporation

September 2008

Poultry do not have the endogenous enzyme lactase that is required to digest lactose in the small intestine.  However, the use of lactose as a prebiotic at low concentrations in diets for poultry has been shown to be effective in improving performance.  This response appears to be a result of shifts in the intestinal microbial population allowing for more microbial fermentation and lactic acid production in the hindgut.  The lowered intestinal pH that results from feeding lactose to avian species results in inhibition of pathogenic bacteria and conversion of ammonia to nonvolatile ammonium ions.  The improved health from decreased enteric disturbance and reduced ammonia in the air space has the potential to improve growth performance.

Initially, the interest in the prebiotic effect of lactose was focused on reducing Salmonella colonization in the ceca (Corrier et al., 1990a,b; Hinton et al., 1990; Ziprin et al., 1990).  However, more recent research has evaluated the potential for lactose to improve rate and efficiency of growth.   In 2003, Douglas et al. demonstrated that inclusions of galactose or lactose at 2 or 4% of the diet increased cumulative gain from day 0 to 21 post-hatch in male broiler chicks.  Interestingly, this response was observed in apparently healthy chicks reared in battery cages and were fed diets that contained growth promoting antibiotic (bacitracin).

In 2006, Simoyi et al. evaluated lactose levels from 0 to 8% in diets for growing turkeys and demonstrated fairly dramatic improvements in body weight after a six week feeding period.  The response to lactose appeared to be optimized at an inclusion level of 2%, however significant weight gain improvements were observed at lactose levels as low as 0.5%.  In a second experiment conducted by the same researchers only a numerical improvement in body weight was observed with the highest final body weight being attained with 2% lactose.  Although the results of fecal pH were highly variable, the authors concluded that generally fecal pH decreased as lactose increased in the diet.  Fecal nitrogen data from these experiments clearly demonstrated an increase in the amount of nitrogen in the feces with lactose inclusion and was presumed by the authors to be a result of the lower fecal pH when feeding lactose and conversion of volatile ammonia into non-volatile ammonium ions.  No antibiotics were fed in these experiments and lactose had no significant effect on whole body composition.

In an experiment designed to evaluate lactose and a lactic acid bacteria under commercial conditions, Torres-Rodriguez et al. (2007) fed 0.1% lactose with or without a probiotic to 10 day old hybrid turkey hen poults in a commercial house for 26 days.  The effect of the probiotic appeared to be minimal in the absence of lactose, however lactose alone improved body weight by 17% after 28 days.  At the end of the experiment, 93 day old hen poults that were fed both lactose and the probiotic were 436 grams heavier at market weight.  There was no diet information presented, but no mention of growth promoting antibiotics was made in the materials and methods.  No feed disappearance measurements were possible due to the design of the experiments in a commercial house so no feed efficiency values could be determined.  The authors concluded that lactose offers a good alternative to improve poultry production when used as a prebiotic.

Vincente et al. (2007) recently reported that providing lactose at 0.1% of the diet with a probiotic for 14 days improved body weight by 10.5% and feed conversion by 9.4% on average of two trials when hen turkey poults were challenged with Salmonella.  No response was observed when the experiment was repeated without the Salmonella challenge.

Also reported in 2007, McReynolds et al. evaluated the effects of dietary lactose levels ranging from 0 to 4.5% on the control of necrotic enteritis in broiler chicks.  All of the control birds (100%) challenged with C. perfringens had clinical intestinal lesions compared to only 30% of birds fed 2.5% lactose.  The mean intestinal lesion score for birds fed 2.5% lactose was 0.22 compared to a mean lesion score of 1.90 for the control birds.  The authors concluded that lactose provides the poultry industry with an alternative that has the potential to promote better animal health and decrease monetary losses due to necrotic enteritis.

The optimal dietary inclusion of lactose is not perfectly clear and may be flock dependent, but it appears that lactose levels near 2% of the diet maximizes rate of gain for broilers and turkeys and protects against Salmonella and necrotic enteritis.  Lactose levels as low as 0.1% improved performance of turkeys.  The growth performance response to lactose appears to be a result of increases in feed intake with either some improvement or no change in feed efficiency.  Prevention of Salmonella colonization and development of necrotic enteritis has been demonstrated and is likely due to the increased lactic acid production in the hind gut that results from lactose feeding.  One report strongly suggests feeding lactose increases fecal nitrogen due to a reduction in volatilization of ammonia which likely leads to improvements in barn air quality.  No reports that included lactose levels below 5% of the diet reported any negative impact of lactose on incidence of diarrhea.  In summary, there are multiple research reports that indicate providing lactose to poultry at low inclusion levels to serve as a prebiotic has a positive effect on bird health and performance.

The addition of lactose to poultry diets has never been more economical, especially in light of today’s higher feed costs.  Whey permeate (80% lactose) prices are at record lows, $0.20/ lb or lower.  Assuming $0.20/lb for an 80% lactose product, the addition of 0.1% lactose to the diet adds $0.50 per ton of feed.  With positive performance responses observed at lactose levels as low as 0.1 to 0.5%, the added cost per ton of feed is $0.50 to $2.50 (possibly less when accounting for the feed cost displaced by the lactose addition).

Literature Cited

Corrier, D. E., A. Hinton, Jr., R. L. Ziprin, R. C. Beier, and J. R. DeLoach.  1990a.  Effect of dietary lactose on cecal pH, bacteriostatic volatile fatty acids and Salmonella typhimurium colonization of broiler chicks.  Avian Dis.  34:617-625.

Corrier, D. E., A. Hinton, Jr., R. L. Ziprin, and J. R. DeLoach.  1990b.  Effect of dietary lactose on Salmonella colonization of market-age broiler chickens.  Avian Dis.  34:668-676.

Douglas, M. W., M. Persia, and C. M. Parsons.  2003.  Impact of galactose, lactose, and grobiotic-B70 on growth performance and energy utilization when fed to broiler chicks.  Poult. Sci.  82:1596-1601.

Hinton, A., Jr., D. E. Corrier, G. E. Spates, J. O. Norman, R. L. Ziprin, R. C. Beier, and J. R. DeLoach.  1990.  Biological control of Salmonella typhimurium in young chicks.  Avian Dis.  34:626-633.

McReynolds, J. L., J. A. Byrd, K. J. Genovese, T. L. Poole, S. E. Duke, M. B. Farnell, and D. J. Nisbet.  2007.  Dietary lactose and its effects on the disease condition of necrotic enteritis.  Poult. Sci. 86:1656-1661.

Simoyi, M. F., M. Milimu, R. W. Russell, R. A. Peterson, and P. B. Kenney.  2006.  Effect of dietary lactose on the productive performance of young turkeys.  J. Appl. Poult. Res. 15:20-27.

Torres-Rodriguez, A., S. E. Higgins, J. L. S. Vicente, A. D. Wolfenden, G. Gaona-Ramirez, J. T. Barton, G. Tellez, A. M. Donoghue, and B. M. Hargis.  2007. Effect of lactose as a prebiotic on turkey body weight under commercial conditions.  J. Appl. Poult. Res. 16:635-641.

Vicente, J., A. Wolfenden, A. Torres-Rodriguez, S. Higgins, G. Tellez, and B. Hargis. 

2007.  Effect of Lactobacillus species-based probiotic and dietary lactose prebiotic on turkey poult performance with or without salmonella enteritidis challenge.  J. Appl. Poult. Res.  16:361-364.

Ziprin, R. L., D. E. Corrier, A. Hinton, Jr., R. C. Beier, G. E. Spates, and J. R. DeLoach.  1990.  Intracloacal Salmonella typhimurium infection of broiler chickens:  Reduction of colonization with anaerobic organisms and dietary lactose.  Avian Dis.  34:749-753.