The Use of Mesquite Pods (Prosopis spp.) as an Alternative to Improve the Productive Performance and Methane Mitigation in Small Ruminants: A Meta-Analysis

Mesquite (Prosopis spp.), a highly nutritious legume from arid regions characterized by its secondary metabolites, offers a cost-effective resource to provide energy and protein for small ruminant farmers in harsh environments. In addition, the high concentrations of secondary metabolites found in mesquite pods could be an option to mitigate methane (CH4) emissions. Thus, the aim of this study was to conduct an analytical review to assess the impact of adding mesquite pods on small ruminant productivity and enteric CH4 emissions. A comprehensive and structured search of scientific articles resulted in a database of 38 trials. The response variables were evaluated through raw mean differences (RMDs) and standardized mean differences (SMDs), followed by a meta-regression, used to investigate the heterogeneity of the explanatory variables. Supplementation with mesquite pods significantly increased the dry matter intake (DMI) and average daily gain (ADG) and reduced the feed conversion ratio (FCR), with sheep showing the highest effect. The meta-regression demonstrated that the mesquite pod effect was influenced mainly by the species, level of incorporation and processing of the pods. Studies employing in silico CH4 estimation reported increased emissions when the diets included mesquite pods. In contrast, in vivo studies demonstrated promising results, showing a significant reduction in CH4 emissions when mesquite pods were included in small ruminant diets. Therefore, future research should focus on evaluating mesquite pod supplementation using precise methods to assess CH4 emissions.