A Meta-Analysis of Whole Blood Cholinesterase Activity in Healthy Ruminants Using a Modified Electrometric...

This meta-analysis aimed to compile and analyze WBChE activity using the modified electrometric method to establish normal or baseline enzyme activity values in ruminants (sheep, goats, cattle, and buffalo).

This is a one-group randomized-effect-size meta-analysis model applied to the mean ± SD of WBChE activities in sheep, goats, cattle, and buffaloes.

Using PRISMA selection, we identified 16 records from five studies that measured WBChE activity in sheep (N=267), goats (N=165), cattle (N=197), and buffaloes (N=31) using a modified electrometric method. The studies included both sexes and were published between 2007 and 2025. The forest plot showed that the WBChE activities of sheep, goats, cattle, and buffaloes were 0.40, 0.32, 0.51, and 0.42 Δ pH/enzymatic reaction incubation time, respectively. Their 95% CI were 0.19-0.60, 0.16-0.49, 0.31-0.70, and 0.39-45, respectively. The weights of the individual records across the four species varied from 0.91% to 14.77%. The I2 heterogeneity index of 61% was moderate and significant (Q=38.35; P=0.001). Despite the low pseudo-R2 value (24.24%), the I2 of subgroup analysis was significant only in sheep (64.2%, Q=14, P=0.016). The funnel plot showed the possibility of publication bias in five imputed studies. However, Egger's regression analysis was not statistically significant (t=1.91, P=0.077). The overall risk of bias in the studies was low.

This study is the first meta-analysis to establish the reference WBChE activity in healthy ruminants, including sheep, goats, cattle, and buffaloes. This is an additional contribution to the existing literature, as the modified electrometric method is recommended for measuring blood or tissue ChE activity in various animal species. These findings provide valuable reference points for the clinical and toxicological assessment of poisoning by cholinesterase-inhibiting pesticides in these species.