J. Appl. Poult. Res.
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J APPL POULT RES 2007. 16:248-254
© 2007 Poultry Science Association
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Research Reports

Use of Yucca schidigera Extract in Broiler Diets and Its Effects on Performance Results Obtained with Different Coccidiosis Control Methods

D. M. Alfaro*, A. V. F. Silva{dagger}, S. A. Borges{dagger}, F. A. Maiorka{dagger}, S. Vargas{dagger} and E. Santin{dagger},1

* School of Agricultural and Veterinary Sciences, Universidade Estadual Paulista, 14884-900 Jaboticabal, São Paulo, Brazil; and {dagger} Federal University of Paraná, 80035-050 Curitiba, Paraná, Brazil

Correspondence: 1 Corresponding author: santin{at}ufpr.br


   SUMMARY
TOP
 SUMMARY
DESCRIPTION OF THE PROBLEM
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS AND APPLICATIONS
 REFERENCES AND NOTES
 
A trial was conducted to assess the effects of the dietary supplement Yucca schidigera extract on the performance of broilers subjected to different coccidiosis control methods. Six hundred male broiler chicks were randomly allocated to 1 of 5 treatments with 4 replicates each. The treatments were as follows: T1, vaccinated against coccidiosis; T2, nonvaccinated, a dietary coccidiostat; T3, vaccinated against coccidiosis, diet supplemented with Y. schidigera extract (0.01%); T4, coccidiostat plus Y. schidigera extract added to feed (0.01%); and T5, nonvaccinated, nonsupplemented control. The parameters analyzed were bird performance and morphology of the intestinal mucosal surface. The intestinal villi were higher at 6 d of age in broilers treated with coccidiostats or vaccinated against coccidiosis and supplemented with Y. schidigera extract compared with groups receiving the vaccine only or no treatment. Addition of the Y. schidigera extract to the diet of vaccinated birds improved average daily gain and feed conversion rate at 42 d of age compared with the other treatments, suggesting there might be a beneficial, synergistic effect between the coccidiosis vaccine and the Y. schidigera extract.

Key Words: broiler • coccidiosis • vaccine • Yucca schidigera extract


   DESCRIPTION OF THE PROBLEM
TOP
 SUMMARY
 DESCRIPTION OF THE PROBLEM
MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS AND APPLICATIONS
 REFERENCES AND NOTES
 
Coccidiosis, an intestinal infection of intra-cellular protozoa of the Eimeria species, is responsible for major losses to the poultry industry, reducing performance and increasing production costs [1]. Coccidiosis outbreaks among broilers are mainly attributed to intensive rearing conditions and the highly infectious nature of the parasitic oocysts, which remain viable for months after shedding. Although host immunity plays an important role in limiting this disease, the control of coccidiosis oftentimes depends on the use of drugs added to the feed (anticoccidial drugs). These drugs have been the first choice of treatment for the industry, because they are effective against all Eimeria species, in contrast to the animal immune response, which is species-specific. Furthermore, vaccine reactions result in transient performance losses [2]. There are many anticoccidials available for the control of coccidiosis. However, in spite of the rotation of coccidiostats, the poultry industry is challenged by the development of Eimeria resistance to multiple drugs [3]. A lack of new active coccidiostats and pressure from international markets to limit drug use have prompted a search for alternative strategies for the control of avian coccidiosis [2].

One proven method for coccidiosis control involves the vaccination of birds with live Eimeria oocysts. This practice is based on well-documented studies that prove the development of immunity after the first coccidiosis infection. Many studies have shown that these vaccines can be as effective as the use of drugs to control coccidiosis outbreaks [4]. In some cases, however, these vaccines can trigger severe reactions that may affect the performance of flocks, mainly in broilers because of their rearing period [5].

Yucca schidigera is a major source of natural saponins that inhibit the development of protozoa by interacting with the cholesterol present on the parasite cell membrane, thus resulting in parasite death [6]. Several studies with saponins have demonstrated their positive effects on improved nutrient absorption by increasing intestinal permeability via membrane depolarization [7]. Based on the emulsifying properties (stabilizing water or oil emulsions) and the intense effect of making monoglycerides more soluble [8], dietary supplementation of saponins will result in the emulsification of oil fats, promoting their digestion. Saponins can also affect the absorption of vitamins and minerals. In rats, for example, they reduce the absorption of Fe [9]. Oral administration of saponins is also correlated to improved animal resistance to field infections (nonspecific immunity), suggesting an immunomodulatory effect [10].

The objective of this study was to evaluate the effects of dietary supplementation with Y. schidigera extract (0.1%) on the performance of broilers subjected to different coccidiosis control programs (vaccination or coccidiostats).


   MATERIALS AND METHODS
TOP
 SUMMARY
 DESCRIPTION OF THE PROBLEM
 MATERIALS AND METHODS
RESULTS AND DISCUSSION
 CONCLUSIONS AND APPLICATIONS
 REFERENCES AND NOTES
 
Six hundred male Ross 308 [11] broilers were distributed in a completely randomized experimental design with 5 treatment groups, with 4 replicates of 30 birds each per experimental unit. The treatments were as follows: T1, vaccinated against coccidiosis; T2 nonvaccinated, treated with coccidiostat via feed (monensin [12] from 1 to 21 d and salinomycin [13] from 22 to 35 d of age); T3, vaccinated against coccidiosis and fed a diet containing 0.01% of Y. schidigera extract; T4, coccidiostat via feed (monensin [12] from 1 to 21 d and salinomycin [13] from 22 to 35 d of age) plus 0.01% of Y. schidigera extract in feed; and T5, nonvaccinated, nontreated control. The Y. schidigera extract contained 6.5% saponins. Birds were raised in pens (12 broilers/m2) under conditions similar to those in commercial production. The birds were housed on floor pen and received feed and water ad libitum. The experimental diets were formulated according to the NRC [14] recommendations for bird life stages (starter and grower). The birds in the T1 and T3 groups were vaccinated against coccidiosis with a commercial vaccine at a dosage of 0.03 mL/bird, approximately 2,300 mix oocysts of Eimeria acervulina, Eimeria maxima, Eimeria mitis, and Eimeria tenella for dose. Vaccine [15] was diluted in distilled water and applied on top of the feed during the first hours after chick placement. Birds and experimental feeds were weighed at the beginning and end of each stage (1, 6, 21, and 42 d of age) to calculate weight gain, feed consumption (FC), and feed conversion rate (FCR).

At 6 d of age, 4 birds from each experimental group were euthanized by cervical dislocation before collecting intestinal samples. The Maiorka technique was used to collect 2-cm-long samples from each portion of the small intestine (i.e., duodenum, jejunum, and ileum) [16]. The fragments were fixated in bouim, dehydrated in alcohol series, clarified in xylol, and included in paraffin blocks, then cut in 5-µm sections and applied to glass slides. The slides were stained with hematoxylin and eosin, and glass cover slips were applied. The slides of the small intestine were read under light microscope using an image analyzer. Morphometric measurements were villus height, crypt depth, and villus:crypt ratio (50 readings per slide). All weight gain, FC, and FCR data, as the measurements of villus height and crypt depth, were analyzed by ANOVA, and those with statistical differences were submitted to the Turkey’s test at 0.05% using Statistix for Windows [17].


   RESULTS AND DISCUSSION
TOP
 SUMMARY
 DESCRIPTION OF THE PROBLEM
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
CONCLUSIONS AND APPLICATIONS
 REFERENCES AND NOTES
 
The morphometric measurements of the intestinal epithelium samples at 6 d of age are given in Table 1Go and Figures 1Go and 2Go. Experimental groups treated with coccidiostat or with coccidiostat plus Y. schidigera extract or with coccidiosis vaccine plus Y. schidigera extract had longer villi in the duodenum than did the group that received the coccidiosis vaccine alone; the shortest villi were in the untreated control (Figure 1Go). The highest villus:crypt ratio was found in birds that were vaccinated and supplemented with Y. schidigera extract, followed by the vaccinated birds, birds treated with coccidiostats in the feed, and birds fed both coccidiostats plus Y. schidigera extract. The villus:crypt ratio of the untreated control was significantly lowest.


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  		Table 1. Average villus height, crypt depth, and villus:crypt ratio measured in small intestine sections collected from broilers from the different treatment groups1
 

Figure 1
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  		Figure 1. Villus height in the duodenum of birds at 6 d of age. T1 = birds vaccinated against coccidiosis; T2 = nonvaccinated birds fed coccidiostat in the feed (30 g of monensin/ton in the starter); T3 = birds vaccinated against coccidiosis and supplemented with Yucca schidigera extract in the feed (0.01%); T4 = birds supplemented with coccidiostat and Y. schidigera extract in the feed (0.01%); T5 = nonvaccinated and nonsupplemented birds.

 

Figure 2
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  		Figure 2. Villus height in the jejunum of birds at 6 d of age. T1 = birds vaccinated against coccidiosis; T2 = nonvaccinated birds fed coccidiostat in the feed (30 g of monensin/ton in the starter); T3 = birds vaccinated against coccidiosis and supplemented with Yucca schidigera extract in the feed (0.01%); T4 = birds supplemented with coccidiostat and Y. schidigera extract in the feed (0.01%); T5 = nonvaccinated and nonsupplemented birds.

 
According to Boleli et al. [18], the height of the villi in the intestinal epithelium is positively related to absorption capacity, and its growth is regulated by 2 cytologic processes: cell turnover and cell extrusion. Higher crypt stimulation rates result in more intense cell proliferation and, consequently, higher villi. Thus, cell lesions caused by microorganisms or parasites, such as Eimeria, may increase cell extrusion rates and reduce villus height.

Although there were no significant differences in crypt depth between the vaccinated and control groups in duodenum, the villus:crypt ratio differed significantly. Thus, it can be suggested that cell turnover was more intense in vaccinated birds, because villus height increased compared with the control.

Supplementation of birds vaccinated against coccidiosis with Y. schidigera extract attenuated the reaction to the vaccine, both in regard to villus height and crypt depth, and resulted in higher villus:crypt ratios among all treatments and suggested a beneficial effect of the supplement on intestinal cell turnover.

Villus height in the jejunum (Table 1Go and Figure 2Go) was the lowest in the birds from the nonvaccinated, nontreated control compared with all other treatments. However, the control birds and those receiving coccidiostats plus Y. schidigera extract had the highest values for crypt depth and the lowest villus:crypt ratios compared with all other treatments. Although the crypt depth and the villus:crypt ratio are the same for birds fed coccidiostats plus Y. schidigera extract and the control group (nonvaccinated, nontreated), villus height was significantly greater in the group receiving coccidiostats plus Y. schidigera extract than in the control group, suggesting that cell turnover was not as effective in the control group as it was in the group fed with coccidiostat (monensin from 1 to 21d and salinomycin from 22 to 35 d of age) plus 0.01% of Y. schidigera extract in feed.

In the ileum, the only treatment-induced variation was in crypt depth, the highest values occurring in birds receiving coccidiostats plus Y. schidigera. However, this same group had a lower villus:crypt ratio than did the vaccinated and control birds. Further studies are needed to fully understand the effects of Y. schidigera extract supplementation on the intestinal mucosa of the animals.

In spite of the morphometric findings at 6 d of age, there were no significant differences seen in FC, BW gain (BWG), or FCR between groups at this age (Table 2Go), perhaps indicating lesions were not severe enough to affect performance. At 21 d of age, FC was higher in the groups treated with coccidiostats and Y. schidigera compared with the control group. Body weight gain was higher in the nonvaccinated groups receiving coccidiostats or coccidiostats plus Y. schidigera extract compared with all other treatments. The FCR did not significantly differ among treatments.


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  		Table 2. Average feed consumption (FC), BW gain (BWG), and feed conversion rates (FCR) at 6, 21, and 42 d of age in the different experimental groups1
 
At 42 d of age, FC was similar among all treatment groups. The highest BWG and most improved FCR were in the vaccinated group supplemented with Y. schidigera extract. Intermediate weight gain values were seen in the groups receiving the vaccine alone, nonvaccinated treated with coccidiostats in the feed, and in nonvaccinated treated with coccidiostats plus Y. schidigera extract. The lowest weight gain was in the negative control group that received no type of coccidiosis prevention. These results can be correlated to the beneficial effects of the coccidiostats in maintaining intestinal health, because it is known that these products act on microorganisms other than coccidia, preventing stimulation of the immune system by pathologic agents [10].

At 42 d of age, the group that received both vaccine and Y. schidigera extract had the best BWG and FCR compared with all other treatments; however, at 21 d of age, this group had poorer performance than that of birds fed coccidiostats. This relationship suggests that the effect of this treatment (vaccine plus Y. schidigera) occurred after 21 d of age, promoting disease resistance and attenuating vaccine performance losses. Apparently, the vaccine worked synergistically with the Y. schidigera extract to improve poultry performance. Further studies are needed to validate the effect of the Y. schidigera extract on poultry performance observed in this study, which utilized only 4 replications per treatment. Some studies have demonstrated that Y. schidigera extract inhibits the development of protozoa [19]. In addition, the presence of glycocomponents in saponins has led to their use as adjuvants, injected by parenteral route with commercial vaccines for rabies, foot and mouth disease, feline leukemia, and bovine mastitis [20].

Studies have demonstrated that substances (saponins) extracted from the Y. schidigera plant can improve the absorption of nutrients by the intestinal mucosal surface [19]. These saponins are steroidal glycosides with strong surfactant activity, reducing the superficial tension of fluids and allowing better absorption of nutrients by the intestinal epithelium. In addition, other studies have shown that saponins have antimicrobial activity, interfering with membrane permeability of microorganisms and having a toxic effect [21]. Although all of the above effects of Y. schidigera may have contributed to the findings of this study, further studies are needed to identify their specific influence.


   CONCLUSIONS AND APPLICATIONS
TOP
 SUMMARY
 DESCRIPTION OF THE PROBLEM
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS AND APPLICATIONS
REFERENCES AND NOTES
 

  1. Birds that had not been vaccinated against coccidiosis and who were fed nonmedicated feed (control) had the poorest performance and smallest villus height on small intestine mucosa at 6 d of age compared with birds receiving the other treatments that included some kind of coccidiosis protection method.
  2. The interaction between the coccidiosis vaccine and the Y. schidigera extract supplement resulted in longer duodenal villi in broilers at 6 d of age compared with birds that had received the coccidiosis vaccine only.
  3. The best weight gain and FCR at 42 d of age occurred in birds receiving the combined vaccine plus Y. schidigera extract treatment compared with all other treatments.


   ACKNOWLEDGMENTS
 
We thank Alltech do Brasil Agroindustrial Ltda., Curitiba, Paraná, Brazil; Empresa Da Granja, Lapa, Paraná, Brazil; and Schering-Plough, São Paulo, São Paulo, Brazil.


   REFERENCES AND NOTES
TOP
 SUMMARY
 DESCRIPTION OF THE PROBLEM
 MATERIALS AND METHODS
 RESULTS AND DISCUSSION
 CONCLUSIONS AND APPLICATIONS
 REFERENCES AND NOTES
 

  1. Chapman, H. D. 2003. Origins of coccidiosis research in the fowl—the first fifty years. Avian Dis. 47:1–20.[ISI][Medline]
  2. Jenkins, M. 2004. Page 3 in Control of Avian Coccidiosis: Drugs and Vaccines. Miscellaneous Publishing Information Bulletin. Feed Information News Service, USDA. USDA, Washington, DC.
  3. Daudschies, A., U. Gässlein, and M. Rommel. 1998. Comparative efficacy of anticoccidials under the conditions of commercial broiler production and in battery trials. Vet. Parasitol. 76:163–171.[ISI][Medline]
  4. Sabaté, E. S., H. Ruiz, and I. Angulo. 2001. Evaluation of the effects of vaccination against avian coccidiosis on the parameters productive of chicken. Zootecnia Trop. 19:359–369.
  5. Santin, E., D. Alfaro, A. V. Fischer da Silva, and S. A. Borges. 2004. Efeito da utilização de mananoligossacarídeo (MOS) sobre o desempenho de frangos de corte vacinados contra a coccidiose. Braz. J. Poult. Sci. 6(Suppl.):194. (Abstr.)
  6. Wang, Y., T. A. Mcallister, C. J. Newbold, L. M. Rode, P. R. Cheeke, and K.-J. Cheng. 1998. Effects of Yucca schidigera extract on fermentation and degradation of steroidal saponins in the rumen simulation technique (RUSITEC). Anim. Feed Sci. Technol. 74:143–153.
  7. Oleszek, W., M. Sitek, A. Stochmal, S. Burda, and P. Cheeke. 1999. Saponin and phenolic constituents from Yucca schidigera bark (Abstr.). Page 31 in Saponins in Food, Feedstuff and Medicinal Plants. Inst. Soil Sci. Plant Cultivation, Pulawy, Poland.
  8. Barla, P., K. Larsson, H. Ljusberg-Wahren, T. Norin, and K. Roberts. 1979. Phase equilibria in a ternary system saponinsunflower oil monoglycerides–water; interactions between aliphatic and alicyclic amphiphiles. J. Sci. Food Agric. 30:864–868.[ISI]
  9. Southon, S., A. J. A. Wright, K. R. Price, S. J. Fairweather-Tait, and G. R. Fenwick. 1988. The effect of three types of saponin on iron and zinc absorption from a single meal in the rat. Br. J. Nutr. 59:389–396.[ISI][Medline]
  10. Cheeke, P. R. 1999. Actual and potential applications of Yucca schidigera and Quillaja saponaria saponins in human and animal nutrition. Pages 1 to 3 in Proc. Am. Soc. Anim. Sci. Oregon State Univ., Corvallis.
  11. Ross 308, Agroceres Avicultura e Nutrição Animal Ltda., Rio Claro, São Paulo, Brazil.
  12. Poulcox, monensin 40%, Indukern do Brasil Ltda., Osasco, São Paulo, Brazil.
  13. Coxistac, 12%, Phibro Animal Health, Guarulhos, São Paulo, Brazil.
  14. NRC. 1994. Nutrient Requirements of Poultry. 9th rev. ed. Natl. Acad. Press, Washington, DC.
  15. Paracox, Schering-Plough, São Paulo, SP, Brazil.
  16. Maiorka, A., A. V. F. Silva, E. Santin, S. A. Borges, I. C. Boleli, and M. Macari. 2000. Influência da suplementação de glutamina sobre o desempenho e o desenvolvimento de vilos e criptas do intestino delgado de frangos. Arq. Bras. Med. Vet. Zootec. 52:487–490.
  17. Analytical Software. Tallahassee, FL.
  18. Boleli, I. C., A. Maiorka, and M. Macari. 2002. Desenvolvimento e reparo da mucosa intestinal. Pages 113–123 in Fisiologia Aplicada a Frangos de Corte. M. Macari, ed. Funep, Jaboticabal, SP, Brazil.
  19. McAllister, T. A., Y. Wang, A. N. Hristov, M. E. Olson, and P. R. Cheeke. 1998. Applications of Yucca schidigera in livestock production. Pages 109–119 in Proc. 33rd. Pac. Northwest Anim. Nutr. Conf., Vancouver, British Columbia, Canada.
  20. Grunwald, C. 1974. Sterol molecular modifications influence membrane permeability. Plant Physiol. 54:624–628.[Abstract/Free Full Text]
  21. Zablotowicz, R. 1996. Effect of saponin on the growth and activity of rhyzosphere bacteria. Pages 23–26 in Saponins Used in Food and Agriculture. G. Waller and K. Yamasaki, ed. Plenum Press. New York, NY.




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