The use of essential oils as a growth promoter for small ruminants: a systematic review and meta-analysis

Abstract

Background: Due to their antimicrobial properties and safety, essential oils are currently proposed as a sustainable option for antibiotic alternatives in the livestock sector. This current systematic review and meta-analysis investigated the effects of dietary essential oil supplements on dry matter intake (DMI), average daily gain (ADG), and feed conversion ratio (FCR) of small ruminants. Methods: A total of 12 studies (338 small ruminants) were included in this meta-analysis. The overall effect size was quantified using Hedges’ g with 95% confidence interval (CI) using a fixed-effect model. Publication bias was inspected using Begg’s and Egger’s tests, followed by trim and fill method to detect the number of potential missing studies. Results: Insignificant heterogeneity among studies was detected both on DMI (P of Q = 0.810; I-square = 0.00%), ADG (P of Q = 0.286; I-square = 17.61%), and FCR (P of Q = 0.650; I-square = 0.00%). The overall effect size showed that essential oils supplementation had no significant impact on DMI (Hedges’ g = -0.12; 95% CI = -0.50 to 0.26; P = 0.429) and FCR (Hedges’ g = -0.17; 95% CI = -0.55 to 0.22; P = 0.284), but had a significant positive impact on ADG (Hedges’ g = 0.44; 95% CI = 0.12 to 0.76; P = 0.002). The result of publication bias analysis showed that DMI, ADG, and FCR did not present any significant biases ( P > 0.10), and no potential missing studies detected. Conclusions: Dietary essential oil could improve ADG of small ruminants, without any alteration on DMI and FCR. Further research in this topic is still required to provide stronger evidence of the potency of essential oil as a growth promoter for small ruminants.

Assessing the In Vitro and In Vivo Effect of Supplementation with a Garlic (Allium sativum) and Oregano (Origanum vulgare) Essential Oil Mixture on Digestibility in West African Sheep

“…Other authors have observed that increased levels of EOs can decrease total digestibility. EOs have the potential to decrease the deamination of amino acids through their effect on ammonia-producing bacteria and protozoa [ 14 , 65 ]. The effect on NDF digestibility can be attributed to the control of the rumen bacterial populations.…”

“…Dietary supplementation with EOs could improve energy balance in small ruminants, where serum glucose and β-hydroxybutyrate (BHB) can be used as reliable indicators of ruminants’ energy status, while blood urea nitrogen (BUN) can indicate nitrogen metabolism [ 32 , 62 , 63 ]. While some studies have suggested that EO supplementation may improve metabolic health and energy metabolism [ 23 , 64 , 65 ], others have reported no significant effects on blood parameters [ 66 , 67 , 68 , 69 , 70 ]. Thus, it is necessary to determine the effect of EO supplementation on energy utilization, fat mobilization, and overall metabolic processes.…”

Antibacterial Activity of Sargassum sp. Extract Encapsulated into Chitosan-Tripolyphosphate Nanoparticles

“…Although this practice provides economic benefits, the overuse of antibiotics evidently contributed to the existence of resistant microbes that threatens both human and livestock [4,5]. For that reason, many countries were then banned the use of antibiotics as growth promoting agents in the livestock sector [6,7]. This situation demanded the search for suitable alternatives to antibiotics.…”

Effects of Brown Seaweed Extract Nanoparticles on Liver Enzymes of Broiler Chickens

“…However, the overuse of AGP led to the emergence of multi-resistant pathogenic microbes growth which threaten both animal and human health. [3][4][5] For this reason, the use of AGP is now prohibited in broiler production [3]. In Indonesia, the ban of AGP was started from 2018 [6].…”