The Efficacy of Additives for the Mitigation of Aflatoxins in Animal Feed: A Systematic Review and Network Meta-Analysis

Abstract

The contamination of animal feed with aflatoxins is an ongoing and growing serious issue, particularly for livestock farmers in tropical and subtropical regions. Exposure of animals to an aflatoxin-contaminated diet impairs feed efficiency and increases susceptibility to diseases, resulting in mortality, feed waste, and increased production costs. They can also be excreted in milk and thus pose a significant human health risk. This systematic review and network meta-analysis aim to compare and identify the most effective intervention to alleviate the negative impact of aflatoxins on the important livestock sector, poultry production. Eligible studies on the efficacy of feed additives to mitigate the toxic effect of aflatoxins in poultry were retrieved from different databases. Additives were classified into three categories based on their mode of action and composition: organic binder, inorganic binder, and antioxidant. Moreover, alanine transaminase (ALT), a liver enzyme, was the primary indicator. Supplementing aflatoxin-contaminated feeds with different categories of additives significantly reduces serum ALT levels (p < 0.001) compared with birds fed only a contaminated diet. Inorganic binder (P-score 0.8615) was ranked to be the most efficient in terms of counteracting the toxic effect of aflatoxins, followed by antioxidant (P-score 0.6159) and organic binder (P-score 0.5018). These findings will have significant importance for farmers, veterinarians, and animal nutrition companies when deciding which type of additives to use for mitigating exposure to aflatoxins, thus improving food security and the livelihoods of smallholder farmers in developing countries.

Keywords: additives; aflatoxins; antioxidant; binders; clay minerals; livestock; mitigation; network meta-analysis; yeast cell wall.

Figure 1

A summary of the screening and selection process to retrieve eligible studies for network meta-analysis.

Figure 2

Percentage number of trials in each additive group: antioxidants (18/43); inorganic binder (13/43); organic binder (12/43).

Figure 3

Random effect model forest plot of serum level of alanine transaminase in poultry birds fed natural diet contaminated with and without aflatoxins. Each data marker represents a study, and the size of the red box is proportional to the weight of the study. The summary effect size is denoted by the blue diamond. References: Liu et al. [29], Subhani et al. [26], Rajput et al. [28], Sridhar et al. [30], Solis-Cruz et al. [25], Sridhar et al. [32], Bintvihok et al. [34], Sadeghi et al. [31], Muhammad et al. [33], Nabi et al. [21], Cao et al. [8], Almusawi et al. [24], Malekinezhad et al. [22], Rashidi et al. [23], Ulaiwi et al. [27], Lin et al. [19], Mesgar et al. [20], Muhammad et al. [33], Rashidi et al. [23], Pappas et al. [44], Allameh et al. [5], Almusawi et al. [24], Mahrose et al. [41], Pappas et al. [44], Barati et al. [7], Rashidi et al. [23], Valchev et al. [42], Xie et al. [4], Stanley et al. [40], Ejiofor et al. [36], Allameh et al. [5], Motawe et al. [38], Barati et al. [7], Rashidi et al. [23], Basmacioglu et al. [39], Hernandez-Ramires et al. [36], Solis-Cruz et al. [25], Cao et al. [8], Salem et al. [37], Barati et al. [7], Ulaiwi et al. [27], Mahrose et al. [41], Pappas et al. [44].

Figure 4

Funnel plot of serum level of alanine transaminase in poultry birds fed natural diet contaminated with and without aflatoxins (p-value = 0.82). The symmetry and p-value indicate no evidence of publication bias.

Figure 5

Forest plot of the efficacy of different additives (compared to control) to restore serum levels of alanine transferase in poultry birds exposed to aflatoxin-contaminated diets. Effects are presented as mean differences (MD), with negative values representing a reduction in the serum level of alanine transferase (higher negative value indicates more efficacy). The horizontal lines indicate 95% confidence intervals.

Figure 6

Funnel plot of network meta-analysis comparing the efficacy of different feed additives to mitigate the toxic effects of aflatoxin on poultry serum alanine transaminase. Egger’s test (p = 0.30) shows no evidence of publication bias.

Figure 7

Map of the world indicating the tropical and subtropical zones.