Hemicell^® is a patented enzyme-based feed ingredient produced by ChemGen Corp. The product's primary enzymatic activity, endo-B-D-Mannanase degrades galactomannan polymers. In this analysis, historical evidence for the anti-nutritive effect of galactomannan in chicken feed is reviewed and compared to the occurrence of galactomannan in common feed components. It is demonstrated that, based on the historical evidence, a broiler diet composed of 30% soybean meal and 60% corn contains an amount of galactomannan expected to deteriorate broiler performance by about 7.5 points in adjusted feed conversion.

Available literature (1-8) was reviewed for the effect of galactomannan inclusion in feed on growth performance using one consistent calculation method. The studies included in this analysis were done at different times (between 1964-1983) by different research groups with widely varying diet ingredients and control feed efficiencies. Also, the period of the growth cycle analyzed varied. For example the data could be from day 1 to 14, 1 to 21, or from day 28 to 56, or could include a complete growth cycle.

The data in the publications were reported in different ways. In this re-analysis, performance data is reported as "points" calculated as weight points and feed/gain points in the following way. For data provided up to 14 or 21 days, a weight point was calculated by the following formula:

(lb.test - lb.control) / (0.4 lb/point) = weight points For older birds, the value of 0.06 lb/point was used in the calculation. The feed/gain (F/G) points were calculated as: (F/G control - F/G test) / (0.01/point) = F/G points

The sum of the F/G points and weight points (usually a negative number) are plotted in figure 1a as negative points. In all cases when significant amounts of galactomannan were included in the feeds, the major contribution to the deterioration in performance was from the worsening of the Feed/Grain calculation. A linear curve was fit to the data (setting zero F/G points at zero percent added guar gum) after removing a few data points at the extremes (positive points or negative points less than negative 200).

Sufficient information to clearly calculate exactly how much galactomannan was added to the various feed formulations was generally not available in the publications. For example, guar meal was typically the source of galactomannan, but the galactomannan content of the guar meal was not always measured. However, in two cases (1,8), both the protein content and the galactomannan content of the guar meal used was reported. A plot of this correlation is shown in Figure 2. In the cases where only the protein content of the meal was given, the percent of gun was predicted from Figure 2. Since the percent of gum in the beans from which the meal was prepared is likely to vary with the exact variety and growth conditions, these estimates likely contribute to the scatter seen in the data. When purified guar gum was used, this analysis assumes it is 100% galactomannan although there could be some impurity such as protein. It also assumes that "guar splits", the raw material used to make guar gum after removal from guar meal, is composed mostly of guar gum.

Despite the diverse nature of the data and the difficulty in exactly matching the nutritional content of control and test diets, there is a clear overall trend showing an increase in negative points proportional to the dose of galactomannan gum in the diet. In 75 of 81 tests there was a negative effect of galactomannan inclusion in the diet (Figure 1a). The anti-nutritional effect of guar meal and other galactomannan containing materials such as copra (9,10) has prevented the effective commercial use of these materials despite a favorable protein content (11,5).

Legume seed (including soybean, and alfalfa) are known to contain galactomannans. Of 163 types of legume seeds tested, 75% contained "mucilage-yielding" endosperms (12). Mucilage is a classical term for viscous polysaccharide polymers that include galactomannan. On a weight basis, galactomannan is five times as viscous as starch, and is one of the most viscous polysaccharides known (16). Mannose and galactose are also present as significant proportions of the non-starch polysaccharides of many commonly used feedstuffs (Table 1) such as wheat, maize, sorghum, barley, oats and rye (13) and canola meal (14). This type of composition data does not establish the exact content of galactomannan since other types of polymers could contain mannose and galactose. It does indicate the upper limit of galactomannan content. Soybean meal, one of the most widely used feed components has the largest mannose and galactose percentages of the feed components listed in Table 1. The galactomannan from soybeans has been purified and soybean hulls have a high content of galactomannan (15).

We believe the effectiveness of Hemicell^® in improving the feed/grain performance of poultry and swine feeds is primarily due to the degradation of galactomannans that are present in currently used feed formulations by the endo-B-D-Mannanase enzyme activity present in Hemicell^®. Figure 1b is the expanded view of the curve in figure 1a, showing expected effects of low amounts of galactomannan on broiler performance.

In a diet with 30% soybean meal and 60% corn and assuming all the mannose is derived from the galactomannan, a galactomannan content of 0.424% is predicted. From figure 1b, a performance deterioration of 7.5 points would be expected from such a galactomannan content.

In controlled broiler pen trials using diets containing 30% soybean meal and 60% corn, the addition of Hemicell^® improved the adjusted feed conversion on average by 7.7 points. Thus, Hemicell^®'s digestion of galactomannan polymer improved broiler performance by an amount consistent with the prediction from historical data.

1. Anderson, J.O. and R.E. Warnick (1964) Value of enzyme supplements in rations containing certain legume seed meals or gums. Poultry Science 43: 1091-1097.
2. Vohra, P. and F.H. Kratzer (1964) The use of guar meal in chicken rations. Poultry Science 43: 502-503.
3. Vohra, P. and F.H. Kratzer (1965) Improvement of guar meal by enzymes. Poultry Science 44: 1201-1205.
4. Couch, J.R., Y.K. Bakshi, T.M. Ferguson, E.B. Smith and C.R. Creger (1967) The effect of processing on the nutritional value of guar meal for broiler chicks. British Poultry Science 8: 243-250.
5. Verma, S.V.S. and J.M. McNab (1982) Guar meal in diets for broiler chickens. British Poultry Science 23: 95-105.
6. Ray, S., M.H. Pubolos and J. McGinnis (1982) The effect of a purified guar degrading enzyme on chicken growth. Poultry Science 61: 488-494.
7. Patel, M.B. and J. McGinnis (1985) The effect of autoclaving and enzyme supplementation of guar meal on the performance of chicks and laying hens. Poultry Science 64: 1148-1156.
8. Nagpal, M.L., O.P. Agrawal and I.S.Bhatia (1971) Chemical and biological examination of guar-meal (Cyamopsis tetragonoloba L.) Indian J. Anim. Sci. 41: 283-293.
9. A.F. Zamora, M.R. Calapardo and E.S. Luis (1988) Nutritional value of copra meal treated with bacterial mannanase in broiler diets. Proceedings of the Eighth International Conference on Global Impacts of Applied Microbiology and International Conference on Applied Biology and Biotechnology. August 1-5, 1988 (Hong Kong), Chinese University Press, pp 497-507.
10. Rao, G.R., T.R. Doraiswamy, K. Indira, B. Mahadeviah and M.R. Chandrasekhara (1965) Effect of fiber on the utilization of protein in coconut cake: metabolism studies on children. J. Exptl. Biol. 3: 163-165.
11. Molina, M.R. and P.A. LaChance (1973) Studies on the utilization of coconut meal: a new enzymatic - chemical method for fiber free protein extraction of defatted coconut flour. J. Food Sci. 38: 607-610.
12. Anderson, E. (1949) Ind. Eng. Chem. 41: 2887.
13. Chesson, A. (1987) Supplementary enzymes to improve the utilization of pig and poultry diets. In Recent Advances in Animal Nutrition -1987, Haresign, W. and D.J.A. Cole (eds), pp71-89, Butterworths, Boston, MA.
14. Slominski, B.A. and L.D. Campbell (1990) Non-starch polysaccharides of canola meal: quantification, digestibility in poultry and potential benefit of dietary enzyme supplementation. J. Sci. Food Agric. 53: 175-184.
15. Whistler, R.L. and J. Saarnio (1957) Galactomannan from soybean hulls. J. Am. Chem. Soc. 79: 6055-6057.
16. Whistler, R.L. and C.L. Smart (1953) Galactomannans, Chapter XI (In) "Polysaccharide Chemistry", Academic Press, New York.

• Maisonnier, S., Gomez, J., Carre, B. 2001. Nutrient digestibility and intestinal viscosities in broiler chickens fed on wheat diets, as compared to maize diets with added guar gum. British Poultry Science (2001), 42: (102-110)
• Bosscher, D., Van caillie-Bertrand, M., Deelstra, H., 2003. Do thickening properties of locust bean gum affect the amount of calcium, iron and zinc available for absorption from infant formula? In vitro studies. International Journal of Food sciences and Nutrition,2003, Volume 54, Number 4, 261-268.
• Gulliford, M.C., Bicknell, E.J., Scarpello, J.H.B., 1988. Effect of Guar on amino acid absorption and the blood glucose, insulin, C-peptide and glucagons responses to jejunal amino acid and glucose perfusion in man. European Journal of Clinical Nutrition, 1988, 42, 871-876.
• Torsdottir, I., Alpsten, M., Andersson, H., Einarsson, S., 1989. Dietary guar gum effects on postprandial blood glucose, insulin and hydroxyproline in humans. American Institute of Nutrition, 1989, 0022-3166/89.
• Mariotti, F., Pueyo, M.E., Tome, D., Benamouzig, R., Mahe, S., 2001. Guar gum does not impair the absorption and utilization of dietary nitrogen but effects early endogenous urea kinetics in humans. Am J Clin Nutr 2001, 74:487-93.
• Nieuwenhoven, M. A., Kovacs, E., Brummer, R., Westerterp-Plantenga, M.S., Brouns, F., 2001. The effect of different dosages of guar gum on gastric emptying and small intestinal transit of a consumed semisolid meal. Journal of the American College of Nutrition, 20s01, Vol. 20, No. 1, 87-91.
• Williams, J.A., Lai, C., Corwin, H., Ma, Y., Maki, K., Garleb, K.A., Wolf, B.W., 2004. Inclusion of Guar Gum ans Alginate into a Crispy Bar improves Postprandial Glycemia in Humans. American Society for Nutritional Sciences, 2004, 022-3166/04.