Glycogen content and In Vitro glycogen consumption in sheep cestode Moniezia expansa (Rudolphi, 1805)

Abstract

Moniezia expansa is common cestode in the small intestine of sheep and causes considerable damage to it. Therefore, an effort to study such biological aspects of Moniezia expansa which would help in its control is much needed. The glycogen content and in vitro consumption of endogenous glycogen was determined in immature, mature and gravid proglottids of Moniezia expansa by Anthrone method by Carroll et al.(1956). The total glycogen (on fresh weight basis) was found to be 3.03%, 4.26% and 3.85% respectively in immature, mature and gravid proglottids of unstarved (control) parasite. The glycogen content in immature, mature and gravid proglottids of parasites starved for 3 hrs. is 2.51%, 3.09% and 2.91% respectively, parasites starved for 6 hrs is 1.91%, 2.0% and 2.0% respectively, parasites starved for 9 hrs. 1.25%, 1.33% and 1.35 respectively and parasites starved for 12 hrs is 0.79%, 0.80% and 0.99% respectively (on fresh weight basis).The endogenous glycogen consumption (in percent of total glycogen content of control parasite) by immature, mature and gravid proglottid was found to be 17.16%, 27.46% 24.42% respectively in parasites starved for 3 hours, 36.96%, 53.05% and 48.05% respectively in parasites starved for 6 hours, 58.75% 68.78% and 64.94% respectively in parasites starved for 9 hours and 73.93%, 81.22% and 74.29% respectively in parasites starved for 12 hours. Rate of consumption of endogenous glycogen between different starvation time periods (in percentage per hour) for immature, mature and gravid proglottids is also calculated. Rate of consumption was maximum during early hours of starvation i.e. between 0–3 hrs and 3–6 hrs and was minimum at 9–12 hrs. Glycogen is the major energy reserve in parasitic helminths which live in low oxygen condition, as they are the best substrate for anaerobic energy production. The study of consumption of endogenous glycogen in cestode during starvation period may be quite helpful for their control in the host. The rate of endogenous glycogen consumption is helpful in understanding metabolic rate and physiological aspects of different proglottids of the parasite.