Potential of field peas and faba beans as protein-rich alternatives for partial or full replacement of soybean meal in broiler chicken diets

Abstract

This study aimed to evaluate the potential of field peas (FP), faba beans (FB), and their combination to replace soybean meal (SBM) in broiler diets. Experimental diets were formulated to progressively replace SBM with FP, FB, or both across four feeding phases: starter (0–10 d), grower (10–24 d), finisher (24–35 d), and withdrawal (35–42 d). Each of the six dietary treatments was replicated 10 times, with 6 straight-run Ross 308 broiler chicks per replicate. Growth performance was monitored, and nutrient utilization was assessed. Protein and starch digestibility were measured at the distal jejunum and distal ileum, and the starch to protein (S:P) disappearance rate and ratios were calculated for each intestinal segment. Progressive replacement of SBM up to 55 % in the starter, 66 % in the grower, and 100 % in the finisher and withdrawal phases resulted in final BW and FCR that were statistically similar to the control SBM-based diets. However, complete replacement of SBM from the grower phase onward significantly reduced BW, FCR, and breast meat yield, particularly in birds offered diets based on FP (P < 0.05). Dietary treatments had no significant effect on AME, AMEn, or the AME:gross energy ratio (P > 0.05). Diets containing FP, FB, or their combination significantly increased nitrogen retention and excreta dry matter, and reduced water intake (P < 0.05). No significant effects were observed on protein or starch digestibility or their disappearance rates at either the distal jejunum or distal ileum (P > 0.05). However, the inclusion of FP and FB significantly increased the S:P disappearance rate ratio in both intestinal segments (P < 0.05). These results indicate that both FP and FB can be used effectively only for partial replacement of SBM in broiler diets. While the increased S:P disappearance rate ratio suggests altered nutrient absorption dynamics and may explain the decline in performance of the birds fed high level of legumes, further investigation on underlying effects on intestinal functions is required.