Aloe vera polysaccharides and proteins as biological response modifiers and their therapeutic efficacy against coccidiosis in chickens

Abstract

There are several natural biological products, which are effective to trigger immune responses in animals and human beings. In this regard, various plant species are considered to be potent natural biological products and their efficacy has been reported in various animal models. In the present study, Aloe (A.) vera derived biomolecules including polysaccharides and proteins were isolated and characterized as biological response modifiers and their subsequent protective effects against coccidiosis in chickens. A total of 640 chicks were randomly divided into two main treatment groups namely A (polysaccharides) and B (proteins), each containing 320 chicks. Each group was administered orally with the graded doses of polysaccharides and proteins for three consecutive days i.e. day 5th, 6th and 7th of age. Cellular immune responses were assessed for in vivo and in vitro lymphoproliferative responses to Phytohemagglutinin-P (PHA-P), Concanavalin-A (Con-A) respectively and Carbon particle clearance assay. Humoral immune responses were detected by microplate haemagglutination assay on 7th and 14th days post primary and secondary injections of sheep red blood cells. Weekly weight gains and feed conversion ratios were also calculated. For therapeutic studies chickens were challenged with mixed Eimeria species on 14th day post administration of A. vera biomolecules. Results revealed significantly higher (p<0.05) lymphoproliferative response to PHA-P and Con-A in chickens administered with A. vera biomolecules as compared to control. Carbon particle clearance assay showed significantly higher clearance index (K) in control group than all biomolecules administered groups and phagocytic index (α) showed significantly higher response in all three biomolecules administered groups as compared to control. Significantly higher total Igs, IgG and IgM titers were also detected in groups administered with A. vera biomolecules. Biomolecules administered chickens showed better feed conversion ratios and significantly higher (p<0.05) weekly weight gains as compared to control. In challenge experiment maximum protection 70% and 57.5% were observed in polysaccharides and proteins administered groups, respectively. Significantly lower oocysts per gram of droppings, lesser lesion scores, better weight gains and higher anticoccidial index were observed in biomolecules administered groups. From the current study, it was concluded that A. vera derived biomolecules have the potential to be used as immunotherapeutic agent(s) in poultry and can be commercialized.