Protective effects of feed additives on broiler chickens exposed to aflatoxins-contaminated feed: a systematic review and meta-analysis.

Aflatoxin contamination in feed is a common problem in broiler chickens. The present systematic review and meta-analysis examined the impact of aflatoxin-contaminated feed and the efficacy of various feed additives on the production performance of broiler chickens fed aflatoxin-contaminated feed (AF-feed). A total of 35 studies comprising 53 AF-feed experiments were selected following PRISMA guidelines. Feed additives included in the analyses were toxins binder (TB), mannan-oligosaccharides (MOS), organic acid (OA), probiotics (PRO), protein supplementation (PROT), phytobiotics (PHY), and additive mixture (MIX). Random effects model and a frequentist network meta-analysis (NMA) were performed to rank the efficacy of feed additives, reported as standardized means difference (SMD) at 95% confidence intervals (95% CI). Overall, broiler chickens fed AF-feed had significantly lower final body weight (BW) (SMD = 198; 95% CI = 198 to 238) and higher feed conversion ratio (SMD = 0.17; 95% CI = 0.13 to 0.21) than control. Treatments with TB, MOS, and PHY improved the BW of birds fed AF-feed (P < 0.05) to be comparable with non-contaminated feed or control. Predictions on final BW from the broiler-fed aflatoxin-contaminated diet were 15% lower than the control diet. Including feed additives in the aflatoxins diet could ameliorate the depressive effect. Remarkably, our network meta-analysis highlighted that TB was the highest-performing additive (P-score = 0.797) to remedy aflatoxicosis. Altogether, several additives, especially TB, are promising to ameliorate aflatoxicosis in broiler chickens, although the efficacy was low regarding the severity of the aflatoxicosis.

Efficacy of Bacillus subtilis to replace in-feed antibiotics of broiler chickens under necrotic enteritis-challenged experiments: a systematic review and meta-analysis.

Necrotic enteritis (NE) and coccidiosis are among the most prevalent infectious diseases in broiler chickens, contributing to large profitability losses. Bacillus subtilis is a promising direct-fed probiotic to counter various pathogens infection in broiler chickens. Here, we performed a meta-analysis to investigate the effects of B. subtilis on broiler chickens performance. A total of 28 studies were selected according to a PRISMA checklist. Random-effect model and mixed-effect model of meta-analysis were fitted to estimate the overall effects of B. subtilis (BS) treatment compared to either the control group (CON) or NE-infected group (NEinf) as a baseline. Hedges' g effect size and its variance were used as estimators of standardized mean difference (SMD) calculation where the results were presented at a 95% confidence interval (95% CI) of the SMD. Overall, NEinf broiler chickens depressed (P < 0.01) body weight (BW), average daily gain (ADG), and feed intake, and elevated (P < 0.01) feed conversion ratio (FCR). Treatment with BS improved ADG and final BW of NEinf with no difference (P = 0.15) between BS and antibiotics (AB), indicating that they had comparable efficacy to treat NE in broiler chickens. BS supplemented to uninfected CON (BSS) improved (P < 0.01) final BW, ADG, and FCR. Compared to CON, BS, and AB failed to recover the FCR but these treatments decreased (P < 0.01) FCR when compared to the NEinf group with similar efficacy (P = 0.97). As expected, NEinf birds had a higher mortality rate (P < 0.01) and higher lesion score (P < 0.01) compared to CON, and treatment using AB and BS successfully decreased (P < 0.01) the mortality rate and lesion score. Compared to BS, AB was more effective to lower (P = 0.01) mortality rate, but comparable (P = 0.65) to minimize lesion score. To conclude, B. subtilis could be an effective natural additive to replace in-feed antibiotics in broiler chickens challenged with C. perfringens. However, the efficacy to reduce mortality rate was better with antibiotics treatment.