The Negative Effects of Subclinical Pregnancy Toxaemia on Fetal Skeletal Muscle Development and Evaluation of the Protective Effects of Dietary L-Carnitine Supplementation in Sheep

Abstract

This study evaluated the effects of subclinical pregnancy toxaemia (SPT) on fetal skeletal muscle development and assessed the potential protective role of L-carnitine supplementation during gestation. A total of 18 crossbred Hamdani ewes underwent oestrous synchronisation, natural mating and pregnancy confirmation via ultrasonography on day 45 post-mating. The ewes were managed according to NRC (2007) dietary guidelines until day 100 of gestation, after which they were assigned to three experimental groups: subclinical PT group (group 1; G1, n = 6), treatment group (subclinical PT + L-carnitine, group 2; G2, n = 6) and control group (group 3; G3, n = 6). Blood beta-hydroxybutyrate (beta HBA) concentrations were measured on day 100 and 138 of the gestation. Then, all ewes were slaughtered for fetal muscle sampling from the Musculus Longissimus Dorsi (MLD) and Vastus Lateralis (VL). Results indicated a significant reduction in muscle fibre number and fibre diameter in both MLD and VL in the SPT group (G1) compared to the control (G3) (p < 0.05). No significant differences were observed between G1 and G2 or between G2 and G3 for these parameters (p > 0.05). On the other hand, large effect sizes for group and pairwise comparisons imply that SPT may negatively affect prenatal muscle development and L-carnitine supports muscle development during the prepartum period. These findings highlight the negative effects of SPT and protective effects of L-carnitine supplementation on fetal skeletal muscle development in ewes with SPT. The observed deficits may negatively impact postnatal growth, survival rates and meat quality. Further investigations are warranted to optimise maternal nutrition strategies and evaluate therapeutic interventions aimed at mitigating the adverse impacts of SPT on fetal muscle development in ruminants. Furthermore, L-carnitine supplementation may be a useful in compensating for the negative effects of SPT.