Prospects of GnRH-loaded on chitosan nanoparticles combined with exogenous progesterone supplementation for treatment of true anoestrus in multiparous Egyptian buffaloes during summer months

Abstract

This study was designed in order to clarify the follicular dynamics, steroid hormones concentrations, and conception rate in true anestrus buffaloes during the summer months. Before beginning, true anestrus was diagnosed via trans-rectal ultrasonography on day 85 and day 95 postpartum by SonoScape scanning. 50 true anestrus multiparous lactating Egyptian buffalo cows with average ages 5-8 years; weighted 400- 450kg, parity 3±0.2 and daily milk production of 10.4±0.6 kg were chosen. Two protocols were applied (GPP group: GnRH-PRID-synch protocol, n=20 and GCP group: GnRH-loaded chitosan-PRID-synch protocol, n=20) and compared with control group, n=10. In day 0 for GPP group, PRID was inserted intravaginally together with 2 ml Gonavet Veyx® (commercial GnRH), then it removed at d7 and buffaloes received 2 ml Estrumate. On day 9, animals received 2 ml Gonavet Veyx® intramuscular and then were artificially inseminated at fixed time 16-20 hr later. The same protocol was performed on GCP group, but Gonadotropins were modified by loading GnRH on chitosan nanoparticles so, buffaloes were recived 1 ml of modified Gonavet Veyx® at d0 and d9. Control group buffaloes received 10 ml intramuscular saline (NaCl 0.9%) on Days 0, 7, and 9, respectively. The serum concentration of (E2 and P4) was estimated. Ultrasonography was used for diagnosis of follicular dynamics. Estrus induction and pregnancy rates were calculated. GCP group had the highest values of E2, P4 and CL size. In addition, improved estrus induction and pregnancy rate in GCP group were noticed compared to other groups but without significant differences.