Urine levels of luteinizing hormone as predictor of the period of ovulation for advantage of timed-artificial insemination in murrah buffalo (Bubalus bubalis )

A proof-of-concept of lateral flow based luteinizing hormone detection in urine for ovulation prediction in buffaloes

We present a method for the detection of luteinizing hormone (LH) in buffalo urine by using gold nanoparticles (AuNPs) conjugated with novel anti-peptide antibodies against LH (anti LHP) in lateral flow assay format. Buffalo LH is an important reproductive hormone and is a chemically complex glycoprotein. Its surge release precedes ovulation and therefore detecting LH has implications in identifying the ovulation event. Any sensor thus developed for sensing LH may have the potential for predicting ovulation and hence can assist herd managers in making decisions on the timing of artificial insemination. Recombinant LH production is time consuming, difficult and costly. Hence, we identified an epitope peptide sequence in buffalo LH and raised antibodies against it. The chemically synthesized peptide and antibodies were used for developing the sensor. The gold nanoparticles and conjugates were characterized through physicochemical methods which confirmed the binding of peptides and antibodies to the gold nanoparticles. A qualitative ELISA for sensing LH was developed based on competitive binding of gold nanoparticles conjugated with the epitope peptide and LH towards the anti-peptide antibodies against LH. We also further explored the detection of LH in buffalo urine using the gold nanoparticle-LHP conjugate (AuNP-LHP) in dipstick format. These experiments provided a proof-of-concept towards applicability of the LH based sensor for ovulation prediction in buffaloes.

Salivary luteinizing hormone: An open window to detect oestrous period in buffalo

Silent oestrus is an unsurmountable problem in the management of buffalo reproduction. In addressing this issue, we have earlier reported variation in the levels of urinary luteinizing hormone (LH) through the different phases of oestrous cycle with an extended window during the mid-oestrous phase. Based on this report, the present study is designed to assess the salivary LH levels in buffalo during the different phases of oestrous cycle. Bovine LH ELISA kit was used to determine the level of salivary LH. We observed a notable variation in salivary LH levels during the different phases of oestrous cycle. The maximum LH level, 39.07 mIU/ml, observed during oestrus, which was significantly (p < .05) higher than other consecutive phases. Altogether, the results showed a significant (p < .05) fold variation during oestrus compared with other phases. Therefore, the study convincingly shows that salivary LH has the potential of application in development of a modality for non-invasive oestrous detection in buffalo.