The effects of dietary seaweed inclusion on growth performance of broiler chickens: a systematic review and meta-analysis

Background: There has been great interest in the use of seaweed as a functional feed ingredient for poultry in the last decade. This study aimed to assess the effects of dietary seaweed inclusion on growth performance of broiler chickens by using a systematic review and meta-analysis approach. Methods: A systematic search of published research articles related to seaweed, broiler chickens, and growth performance was conducted using three online databases (Scopus, PubMed, and SciELO). Mean values, standard deviation, and sample size were extracted from each eligible study. The estimated effect size was then quantified using Hedges’ g with a 95% confidence interval (CI). Data were pooled using a fixed-effect model due to the absence of heterogeneity after being pre-checked using the I (2) statistic. Results: A total of six studies (nine comparisons) involving 2,257 broiler chickens were accommodated in this study. The seaweed type consisted of seaweed blend, Laminaria japonica, Undaria pinnatifida, Hizikia fusiformis, and Ulva lactuca. The inclusion dose ranged from 2 to 30 g/kg, while the intervention duration ranged from 21 to 42 days. No substantial heterogeneity among studies ( I(2) = 0.00%) was found for feed intake, body weight gain, and feed conversion ratio. Dietary seaweed had no significant effect on feed intake (Hedges’ g = 0.19; 95% CI = -0.22 to 0.60; P = 0.280). However, broiler chickens fed dietary seaweed had superior body weight gain (Hedges’ g = 0.64; 95% CI = 0.22 to 1.06; P = 0.000) and preferable feed conversion ratio (Hedges’ g = -0.53; 95% CI = -0.95 to -0.11; P = 0.004). Conclusions: The current investigation highlights that dietary seaweed had growth-promoting potency for broiler chickens. However, more research on this issue is still required to build more comprehensive evidence.