Role of Saponin as Feed Additive for Poultry

Pashu Sandesh, 14th July 2018

Anchal Keshri,  Digvijay Singh,Vandana Kumari Leitanthem,Shahid Hassan Mir, Lamella Ojha, Aditya Agrawal and Anupama Tarun

Introduction

Poultry, basically broiler is an important protein source for people in developing countries. Under intensive condition, broiler production is disturbed by disease attack due to poor biosecurity management. Feed additives like coccidiostat and antibiotic growth promoter/AGP) that added to feed for disease prevention and growth improvement, have been banned by many countries due to antibiotic resistance. Antibiotic growth promoter can be substituted by bioactive compounds of certain plants which can improve production of meat in broilers. saponin can be one of them, it is a glycoside. Saponin extracts or saponin containing plants have several functions, such as anticoccidia, immunostimulant, antibacteria and antifungal. Sustainable poultry production requires continues supply of feed ingredients and additive with consistent in quality.

Structure and source of saponin

Saponins are perse group of plant secondary metabolites. Basically, saponin consists of an aglycone (sapogenin) attached with one or more sugar moieties. Based on the structure of its aglycone, saponin is classified into triterpene saponin and steroidal saponin. The word “sapon” means “foam”, which indicates that saponin exhibits foaming property. The foam was formed when the hydrophilic part of saponin was pulled into the water layer causing reduced surface tension of water and later form bubbles. The saponin was detected in different parts of plant that have foaming property and exhibit haemolytic activity. The highest concentration of saponin was found in tea leaves which has been extracted and semipurified. The highest foam volume indicates the high saponin content in the plant part or plant materials

Effect of saponin on poultry performance

Saponin in the plant material has several functions when fed to poultry. These functions will be beneficial for chicken itself or for human who consume the meat. . saponin fed chicken showed  improvements of chicken performance may be due to the increased villus height and crypt depth. A mixture of saponin contaning plants (yucca and quillaja) enriched with quillaja polyphenol caused improvement in body weight gain, feed conversion. Different type of saponin makes difficult to determine the best level of inclusion in the feed, therefore, the maximum level of inclusion of each saponin given to chicken should be carefully tested since the higher inclusion may give adverse effect on chicken performance.

Saponin as anticoccidial agent

Common diseases occur in poultry is coccidiosis. It is caused by protozoa belongs to the genus Eimeria which can infect in various sites of intestine and caecum. There are many Eimeria have been identified in different poultry and present in different part of intestine. The most pathogenic strains that found in chicken are Eimeria tenella and Eimeria necatrix. The bioactive compound of plant plants exhibit anticoccidial properties. Saponin as one of bioactive compounds reduced significantly protozoa in rumen, therefore, it is expected that saponin may also reduce Eimeria sp in poultry digestive tract. Saponin lysed the ruminal protozoa by directly binding the outer membrane of protozoa.

Saponin as immunostimulant

One of the significant roles of saponin is its use as adjuvant in vaccines. Saponin has been used in several vaccines as adjuvant to increase immunogenicity of an antigen resulting in increased antibodies and cytotoxic of T-lymphocytes, hence improved the efficacy of vaccine.

Saponin as cholesterol reducing agent

Triglyceride and cholesterol are two compounds that become the major concern related to human health, and many people will avoid consuming high content of triglyceride (fat) and cholesterol in their food including meat. Saponin  reduces cholesterol in the meat or blood. The use of S. rarak fruit pericarp that contains high saponin content reduced triglyceride and cholesterol in chicken blood plasma. Alfalfa saponin extract (ASE) administration inhibited gene expression of two key enzymes of cholesterol biosynthesis,

Saponin as antifungal agent

In humid tropical countries, mycotoxin producing fungi grow very easily in food or feed ingredient. Several mycotoxins such as aflatoxin, fumonisin, zearalenone cause negative effect on animal production. Antifungal agent is usually added in the animal feed to prevent the growth of mycotoxin producing fungi. Several steroidal saponins isolated from Capsicum frutescens can inhibit the growth of germinated Aspergillus flavus, A. fumigatus, and A. niger but not Fusarium moniliforme and F. oxysporum . The mechanism of saponin inhibit the fungi was through its binding with steroids that present in the fungal membrane and these saponin-steroid complexes caused a loss of cytoplasmic constituents, leading to cell death. Not only it has antifungal property, saponin also shows antibacterial activity. It may be interact in some ways with bacterial cell wall and caused disruption of bacterial cell membrane.

Saponin as antioxidant

Feed rich in fat especially in highly unsaturated fatty acids may go autoxidation and become rancid. The rancidity may cause refusal to poultry to consume feed and or reduce nutrient content and cause detrimental to poultry. Many feed mills may use an antioxidant as feed additive to prevent autoxidation of feed and the antioxidant are usually derived from chemicals such as ethoxyquin, Butylated Hydroxy Anisole or Butylated Hydroxy Toluene. Many phenolic compounds from plant materials were reported to have antioxidant activity including some saponins. Tritepenoid saponin extracted from Xanthoceras sorbifolia nutshell inhibited tyrosinase activity, had higher scavenging effect than vitamin C suggesting that this saponin extract had high antioxidant activity

Conclusion

            Saponin extracts or saponin containing plants can be used as alternative feed additives especially coccidiostat and antibiotic growth promoter (AGP) in poultry production. Beside the function as coccidiostat and AGP, saponins have also different functions in animal production including immunostimulant for animal health, inhibit the fungus growth and have antioxidant properties. However, it has to bear in mind that efficacy of saponin would depend on the level of application to the feed. Higher application may cause negative effect while lower level may reduce its efficacy. Saponin can be used as feed additive in commercial scale to provide economic benefit to poultry and may be to other animal production.

Anchal Keshri*¹,  Digvijay Singh¹,Vandana Kumari Leitanthem¹,Shahid Hassan Mir¹, Lamella Ojha¹, Aditya Agrawal² and Anupama Tarun³

¹ Ph.D. Scholar, National Dairy Research Institute, Karnal (Haryana)-132001            

² Ph.D. Scholar, Indian Veterinary Research Institute, Izatnagar, Bareilly (UP) -243122

³ M.V.S_C Scholar, National Dairy Research Institute, Karnal (Haryana)-132001

Corresponding author*email; anchalkeshri05@gmail.com