The effect of L-acetylcarnitine on some reproductive functions in the oligoasthenospermic rat

Effect of L-carnitine administration on the seminal characteristics of oligoasthenospermic stallions

The effect of orally administered l-carnitine on the quality of semen obtained from stallions with different semen qualities was investigated. Four stallions with proven fertility (high motility group, HM) and with normal seminal characteristics (>50% progressive motility and > 80 x 10(6) spermatozoa/ml), and four questionable breeders (low motility group, LM) with <50% of sperm progressive motility and < 80 x 10(6) spermatozoa/ml, received p.o. 20 g of l-carnitine for 60 days. Blood and semen samples were collected before treatment (T0) and after 30 (T1) and 60 days (T2). Semen evaluation were performed on five consecutive daily ejaculates (n = 120 ejaculates) and conventional semen analysis was carried out on each ejaculate, both at collection and after refrigeration for 24, 48, and 72 h. Furthermore l-carnitine, acetylcarnitine, pyruvate, and lactate concentrations, and carnitine acetyltransferase activity (CAT) were determined both in raw semen and seminal plasma. There were an increase in progressive motile spermatozoa only in the LM group (26.8 +/- 12.9, 39.1 +/- 15.5, and 48.8 +/- 8.6 for T0, T1, and T2, respectively). Free seminal plasma carnitine concentration was higher in the LM group compared to the HM one. Both pyruvate and lactate were higher in the LM group. Raw semen and seminal plasma carnitine and acetylcarnitine levels correlate positively with both sperm concentration and progressive motility; moreover, acetylcarnitine content was positively correlated with total motile morphologically normal spermatozoa. In conclusion, oral administration of l-carnitine to stallions with questionable seminal characteristics may improve spermatozoa kinetics and morphological characteristics; whereas, it seem to be ineffective in normospermic animals.

Effects of dietary l-carnitine supplementation on semen characteristics in boars

In some species, dietary supplementation with L-carnitine has been reported to increase sperm concentration and sperm motility. The objective of these experiments was to test the hypothesis that L-carnitine supplementation improves the semen characteristics of boars. In Experiment 1, boars (258 days of age) were fed daily a control diet (n = 9) or the control diet plus L-carnitine (500mg per day; n = 9 ). Semen was collected weekly from Weeks 0 to 15 and on 4 consecutive days during Week 16. Experiment 2 was similar to Experiment 1 except boars ( n = 10 per treatment) were 504 days of age. For the weekly and intensive collections there were no consistently positive effects of treatment on semen volume, sperm concentration, total spermatozoa, or sperm motility. Spermatozoa from L-carnitine-treated boars did not display an enhanced ability to maintain motility during 7-day liquid storage. In conclusion, indicators of semen quality were not enhanced by dietary supplementation of L-carnitine in boars.

Identification of human CDV-1R and mouse Cdv-1R, two novel proteins with putative signal peptides, especially highly expressed in testis and increased with the male sex maturation

Human systemic carnitine deficiency (SCD) is a hereditary disease caused by the mutation of OCTN2 and has the characteristics of cardiac hypertrophy. Previous studies based on JVS mouse, an animal model of this disease, showed that Cdv-1 was highly expressed in ventricles of normal mouse, but was remarkably down-regulated in JVS mouse and can be up-regulated to normal level by breeding carnitine, which suggested Cdv-1 was possibly involved in cardiac hypertrophy caused by carnitine deficiency. In this study, the expression of human CDV-1, a homolog of mouse Cdv-1, was undetectable in heart by northern hybridization. The inconsistent expression levels of human CDV-1 and mouse Cdv-1 in heart implied that cardiac hypertrophy in human SCD might not be associated with the abnormal expression of CDV-1. Interestingly, another long transcripts of the gene, Cdv-1R/CDV-1R, were cloned in the present study, in mouse and human, respectively. This long transcript predominantly expressed in both human and mouse testis and its expression level was increased with testis development. Furthermore, we proved that the open reading frame of Cdv-1R/CDV-1R spans the exons 2 approximately 19 instead of exons 9 approximately 19; and the peptide encoded by CDV-1R was composed of 676 amino acids containing a putative signal peptide instead of 414 amino acids described previously. In addition, it was proved that the expression level of Cdv-1R in JVS mouse testis was as high as that in normal mouse testis, and both were not regulated by carnitine.