The present study examined the effect of melatonin implants on follicle growth in dromedary camels two months ahead of their natural breeding season (December to March). Female camels (n Z 6) were treated with melatonin implants at the dose rate of 1 implant per 28 kg body weight sc. Control camels (n Z 6) were administered an SC placebo implant of 8 ml vitamin A. Ovarian ultrasonography was performed at weekly interval upto 7 weeks. Camels were mated with virile stud when a follicle (!10 mm) was visible on either of the ovaries. Blood was collected on day 7, 9, 15, 20, 25 and 30 for assay of plasma progesterone and sonography performed at the same time. Small follicles (2-3 mm) appeared around the periphery of ovaries in 83.3% of camels by day 7 and in 100% camels by day 14. By the end of 7th week an ovulatory size follicle (!1.0 cm) could be observed in 83.3% of treated camels, and these camels were mated with virile studs. In control group, small follicles appeared at the periphery of ovaries only in 66.6% camels but did not progress in growth except in one camel (16.6%) however, ovulating size (!10 mm) follicle was not observed in any camel by the end of 7th week. All treated camels ovulated and one treated camel became pregnant while early embryonic death occurred in one camel. Nonepregnant camels of both groups were mated during the breeding season. All camels of treatment group and 33.33% camels of control group became pregnant by the end of breeding season (April 2010). It was concluded that melatonin implants can augment the follicle growth in lactating camels ahead of the breeding season and pregnancy can occur on mating. Fertility of treated camels during the breeding season is improved.Sommario Nel presente studio viene esaminato l'effetto di impianti di melatonina sulla crescita del follicolo in dromedari -cammelli, nei due mesi precedenti il loro periodo di * Corresponding author.E-mail address: gnpobs@gmail.com (G.N. Purohit). , 25 e 30 giorno, per il dosaggio del progesterone plasmatico e l'ecografia eseguita allo stesso tempo. Follicoli piccoli (2-3 mm) sono apparsi nella periferia delle ovaie nel 83,3% dei cammelli al 7 giorno e nel 100% dei cammelli al 14 giorno. Entro la fine della VII settimana un follicolo ovulatorio di una certa dimensione (! 1,0 cm) è stato osservato nel 83,3% dei cammelli trattati, e questi cammelli sono stati fatti accoppiare. Nel gruppo di controllo, sono apparsi piccoli follicoli alla periferia delle ovaie solo nel 66,6% dei cammelli, ma senza progresso nella crescita, fatta eccezione per un cammello (16,6%), tuttavia, la dimensione di un follicolo ovulatorio (! 10 mm) non è stata osservata in nessun cammello, entro la fine della VII settimana. Tutti i cammelli trattati hanno avuto un'ovulazione e un cammello è rimasto incinta, mentre è avvenuta la morte precoce di un embrione in un altro cammello. I cammelli non gravidi di entrambi i gruppi sono stati accoppiati durante la stagione riproduttiva. Tutti i cammelli del gruppo di trattamento e 33,33% dei cammell...

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The present study aimed to evaluate the effects of exogenous administration of melatonin to male camels on reproductive behaviour, seminal parameters, and serum concentrations of melatonin and testosterone during the non-breeding and subsequent breeding seasons. In September 2018, male camels (n=12) were randomly allocated to subcutaneous injections of either melatonin (MLT, 0.643 mg/kg; n=6) dissolved in corn oil, or plain corn oil; (control n=6). The camels were observed for behavioural signs of rut. A second dose of either MLT (1 mg/kg) or corn oil (control) was administered on 7 October 2018 subcutaneously, as camels did not show any change in behaviour until 6 October 2018, and the camels were again observed for behavioural signs of rut. Blood was collected from all camels on 1 September 2018, and then at weekly intervals until 7 January 2019. The serum was separated and stored until further assay of serum melatonin and testosterone using ELISA kits. Semen was collected from camels showing signs of rut period, and the reaction time, copulation time, and seminal parameters were evaluated. Data obtained was analysed by using the computer program SPSS (version 25; IBM Corp.), and means and standard errors were compared. Male reproductive behaviours (protrusion of soft palate, poll gland secretions, frequent urination, increased frothy salivation) were more pronounced in MLT-treated camels (83.33%) than in control camels (50%). Reaction time and copulation times were lower (112.81±30.06s and 229.8±37.91s) in MLT-treated camels than in controls (359.00±41.35s and 301.89±93.90s). Higher semen volume was observed in MLT-treated (5.34±2.06mL) than in control (3.11±1.75mL) camels (P<0.01). Semen collected from MLT-treated camels had more gel formation (81.25%), significantly higher sperm motility (67.50±2.32%), and increased sperm concentration (326.56±38.67 million mL−1) compared with samples obtained from the control males (P<0.01). Serum melatonin concentrations increased in both treated and control camels during the breeding season compared with concentrations before the breeding season. In MLT-treated camels, serum melatonin concentrations increased significantly and continued to be significantly higher than that in control camels for the entire study period (P<0.01). Serum testosterone concentrations were higher in both MLT-treated and control camels during the breeding season compared with those during the non-breeding season (P<0.01). We concluded that exogenous subcutaneous MLT administration improves sexual behaviour, seminal parameters, and serum testosterone concentrations during both the non-breeding and breeding seasons.

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