Applications of saponins as feed additives in poultry production

Saponins are natural detergents or surfactants found in a wide variety of plants. The major commercial saponin-containing products are those derived from Yucca schidigera and Quillaja saponaria. Yucca is harvested from the wild in northern Mexico, while quillaja is a tree native to the Andes region of South America. It is harvested from the wild in Chile. Plantation production of quillaja also has begun. Saponins have detergent properties because they contain both water-soluble and lipid-soluble moities. They consist of a lipophilic nucleus with one or more side chains of carbohydrate, which confer water solubility. In yucca saponins, the nucleus (sapogenin) is a steroidal structure (Oleszek et al., 2001), while in quillaja saponins the sapogenin is a triterpenoid.
Yucca and quillaja products are available to the feed industry as extracts and whole plant powders. The extracts contain water-soluble components, while the whole plant powders contain all phytochemicals present in the plants. Although yucca and quillaja have traditionally been viewed mainly as sources of saponins, they also contain other phytochemicals, including oligosaccharides and polyphenolics (Oleszek et al., 2001). These constituents may contribute to the beneficial properties of these products as feed additives. Some of the positive effects of yucca and quillaja as feed additives are the following: (i) reduction of environmental ammonia and odor, (ii) hypocholesterolemic activity, (iii) antiinflammatory activity (iv) anti-protozoal activity, (v) nematocidal activity and (vi) growth promotion and improved feed conversion efficiency.

Mechanisms of action to account for these effects will be briefly described here. Yucca contains polyphenols which bind ammonia and hydrogen sulfide, thus improving air quality in poultry houses. Saponins in both yucca and quillaja bind cholesterol, accounting for hypocholesterolemic activity and reduction of egg cholesterol contents. The cell membranes of all animals contain cholesterol. Binding of saponins to membrane cholesterol can modify membrane function and structure. Cholesterol binding accounts for the anti-protozoal activity of saponins (McAllister et al., 2001). Quillaja saponins are used commercially as nematocidal agents in crop production. Their nematocidal activity is probably a result of membrane cholesterol binding. Effects of saponins on nematode parasites of livestock and poultry have yet to be investigated. Anti-inflammatory effects of yucca have been attributed to polyphenolics such as resveratrol and yuccaols (Marzocco et al., 2004). Anti-inflammatory agents reduce formation of cytokines, reducing the diversion of nutrients from growth to immune responses. Anti-inflammatory activity has been advanced as the explanation of the growth-promoting effects of antibiotics (Niewold, 2007).
Nutrafito Plus is a proprietary feed additive (Desert King International) containing whole plant powders of yucca and quillaja, enriched with quillaja polyphenols. A series of broiler trials with Nutrafito Plus were conducted in the United States and Mexico, under the sponsorship of Desert King International.

Trial 1 was conducted at the International Institute for Animal Research at Queretaro, Mexico. The Institute is located 1800 meters above sea level. Ross-Ross 308 chicks were used, with 20 males and 20 females per cage. There were three floor cages per treatment, for a total of 120 birds per treatment. The floor cages were four square meters. The experimental period was 49 days. The negative control diet was based on sorghum, supplemented with soybean meal, and containing no growth promotants. The positive control diet contained 100 ppm Flavomycin (4%). Treatments were negative control plus 100 ppm and 150 ppm Nutrafito Plus, and positive control plus 100 ppm and 150 ppm Nutrafito Plus. All treatments contained 0.550 kg monensin per ton.
The feeding program was as follows: starter phase, 0-21 days; grower phase, 21-35 days; finisher phase, 35-49 days. Feed and water were available ad libitum. The ventilation program was by use of side windows and interior fans. Lighting was natural day light. Results were statistically analyzed using a totally randomized distribution model.
Growth rate, feed intake and feed conversion data are shown in Table 1. Weight gain and feed conversion were improved (P < 0.05) in the positive control versus the negative control. All treatments with Nutrafito Plus had higher gain (P < 0.05) and improved feed conversion (P < 0.05) compared with the positive control. There were no statistically significant differences between the groups fed Nutrafito Plus alone or with the antibiotic.

Table 1 Performance parameters of broilers fed Nutrafito Plus with or without an antibiotic growth promoter at 49 days post-hatch (Mexico).

Data for % breast meat and % abdominal fat are shown in Table 2. These parameters were not affected by dietary treatment. There were no differences in mortality, which was low. The only group with no disease-related mortality was the 100 ppm Nutrafito Plus group.

 Table 2 Carcass parameters of broilers fed Nutrafito Plus with or without an antibiotic growth promoter (Mexico)

The main conclusion of this trial is that Nutrafito Plus gave results in terms of growth and feed conversion that were superior to those obtained with an antibiotic growth promoter. This indicates that Nutrafito Plus is a potential replacement for antibiotic growth promotants in broiler diets.

The second trial was conducted at Mississippi State University. Male Ross 708 broiler chicks were used. There were 6 pens per treatment, with 13 birds per pen, for a total of 312 birds. Corn-soy diets were used: pre-starter, 0-7 days; starter, 7-21 days; and grower, 21-42 days. Feed and water were ad libitum, and lighting was 23 light:2 hour dark. Treatments were negative control (NC), NC + bacitracin, NC + 100 ppm Nutrafito Plus, and NC + 150 ppm Nutrafito Plus. All diets contained monensin at 90 g per ton.
There were no significant differences in growth or feed conversion compared to the negative control or to the positive control containing Bacitracin (Table 3). However, the reduction in mortality with Nutrafito Plus was statistically significant. There was slight evidence of anti-inflammatory activity (Table 4). There were no effects on carcass parameters (Table 5). In contrast to Brazilian studies with quillaja powder (Cheeke and otero, 2005), no effects on intestinal villi were noted (Table 6). Finally, litter parameters were not affected (Table 7).

Table 3 Effect of Nutrafito Plus on performance parameters of broilers (Mississippi State)

 

Table 4 Immune responses and lymphoid organ relative weights of broilers fed bacitracin or Nutrafito Plus (Mississipii State)

 

Table 5 Carcass parameters of broilers fed bacitracin or Nutrafito Plus (Mississippi State)

 

Table 6 Jejunal-villi length and width (microns) of broilers fed bacitracin or Nutrafito Plus (Mississippi State)

 

Table 7 Litter characteristics at day 42 of broilers fed bacitracin or Nutrafito Plus (Mississippi State)

 

 In this trial, bacitracin and Nutrafito Plus gave similar results. The most interesting finding was a sharp reduction in mortality of broilers fed Nutrafito Plus and a tendency of lower feed conversion (not statistically significant).

The third trial with Nutrafito Plus was conducted at Texas A&M University. Cobb x Ross straight run broiler chicks were used. There were 20 chicks per pen with 10 replications per treatment. The starter and grower diets contained an anticoccidial (Coban 60) at 454 g per ton. The starter phase was 0-21 days; grower, 21-35 days; and finisher, 35-42 days. Corn-soy diets were used. Treatments were Negative Control (NC), NC + BMD 50 (454 g/ton), NC + 100 ppm Nutrafito Plus, NC + 150 ppm Nutrafito Plus, and NC + 100 ppm Nutrafito Plus + BMD 50 (454 g/ton).
Both Nutrafito Plus and BMD increased rate of gain and final body weights (Table 8). Feed conversions were also improved. Mortality averaged 3.6% and was not affected by treatment.

Table 8 Performance of broilers fed Nutrafito Plus (Texas A&M)

All treatments with Nutrafito Plus (2 through 5) resulted in significantly lower litter ammonia (P < 0.05) at week four of the study (Table 9) but no treatment was significantly different from the control (P < 0.05) at week six.

Table 9 Environmental ammonia readings of broilers supplemented with BMD50 or Nutrafito Plus (Texas A&M)

 V. CONCLUSIONS

In three trials, Nutrafito Plus produced improvements in growth, feed conversion and other performance data that were similar to those seen with antibiotic growth promoters. Based on these findings, it is apparent that Nutrafito Plus is a valuable feed supplement for broilers, and potentially can serve as a replacement for antibiotic growth promoters.

ACKNOWLEDGEMENTS

These trials were conducted as contract research. The Texas A&M trial was sponsored by Prince Agri Products, Inc. The Mexico and Mississippi State trials were sponsored by Desert King International. Investigators were: Mexico: Dr. M. Forat, Dr. V. Navarro, Mississippi State University: Dr. A. Corzo, Texas A&M University: Dr. C. Bailey.

REFERENCES
Marzocco S, Piacente S, Pizza C, Oleszek W, Stochmal A, Pinto A, Sorrentino R, Autore G (2004) Life Sciences 75, 1491-1501.
McAllister TA, Annett CB, Cockwill CL, Olson ME, Wang Y, Cheeke PR (2001) Veterinary Parasitology 97, 85-99.
Niewold TA (2007) Poultry Science 86, 605-609.
Oleszek W, Sitek M, Stochmal A, Piacente S, Pizza C, Cheeke P (2001) Journal of Agricultural and Food Chemistry 49, 747-752.