Evaluation of pea protein isolates as a protein source for broilers

Abstract

A study was conducted to determine the effect of including pea protein isolate (PPI) in diets for broilers on performance, visceral organ weights, and nutrient digestibility. A total of 192 day-old chicks were assigned to 4 diets with 6 birds per cage and 8 replicates per treatment for a 21-d study. The diets included a corn-soybean meal-based basal diet with 0, 5, 10, or 15% of PPI. Total BW and feed disappearance were monitored weekly to determine ADG, ADFI, and feed conversion ratio per cage basis. Excreta samples were collected during the last 3 d of the experiment to determine the apparent total tract retention (ATTR) of protein and energy. On day 21, 3 birds from each cage were euthanized to collect ileal digesta to determine the apparent ileal digestibility (AID) of energy and amino acids (AA), and visceral organs were weighed. Increasing dietary inclusion of PPI resulted in a linear decrease in overall ADFI (P = 0.002) and ADG (P = 0.001), and a linear increase in feed conversion ratio (P = 0.013). Dietary PPI quadratically increased (P = 0.005) the spleen weight. The weight of proventriculus showed both linear (P = 0.023) and quadratic (P = 0.005) reduction while the weight of gizzard was quadratically reduced (P = 0.002) with the increase in dietary PPI content. Weights of small and large intestine showed both linear (P < 0.05) and quadratic (P < 0.05) reduction with increasing dietary PPI content. An increase in the dietary level of PPI resulted in a quadratic reduction (P < 0.05) in ATTR of DM and CP. The AID of His, Asp, Glu, Gly, and Ser showed a quadratic reduction (P < 0.05), Tyr a linear reduction (P = 0.031) and Cys and Pro both linear (P < 0.05) and quadratic (P < 0.05) reduction with dietary inclusion of PPI. In conclusion, formulating diets with increasing PPI linearly decreased the growth performance of broilers.