The evaluation and enhancement of the nutritive value of yellow-, green- and brown-seeded pea cultivars for unpelleted diets given to broiler chickens

The evaluation and possible enhancement of the feeding value for broiler chickens of yellow-, green- and brown-seeded pea cultivars were studied in three experiments. In the first experiment, bioavailable energy (AMEn), apparent protein digestibility (APD) and starch digestibility were determined. Dietary AMEn, APD and starch digestibility values were decreased (P ≤ 0.05) with 500 g kg−1 inclusion of peas. The AMEn and starch digestibility were similar (P ≥ 0.05) in yellow- and green-seeded cultivars but lower (P ≤ 0.05) in the brown-seeded cultivar. Significant differences (P ≤ 0.05) were found between the cultivars in APD. The effects of feeding 0, 100, 200 and 400 g kg−1 of these cultivars on the performance of broiler chicks were examined in the second experiment. Concurrently the possibility of alleviating the detrimental effects of antinutritional factors in peas by providing excess (115% of National Research Council (NRC) requirements) crude protein (CP) and essential amino acids (EAAs) to 400 g kg−1 pea-based diets was evaluated. The inclusion of up to 200 g kg−1 of peas did not affect weight gains but feed conversion ratio (FCR) was reduced (P ≤ 0.05) only for the diet containing the brown-seeded peas. When peas comprised 400 g kg−1 of a diet fed to broiler chicks, weight gains and FCR were depressed (P ≤ 0.05). However, this depression was alleviated by supplying excess CP and EAAs to these diets. Feed consumption was not affected by dietary inclusion of peas. The influence of adding pectinase only or in combination with protease to diets in which peas constituted a major dietary protein source was investigated in experiment 3. Supplementation of diets containing 800 g kg−1 peas with pectinase alone increased (P ≤ 0.05) weight gains by 7.3 percentage units, above non-supplemented diets. Feed consumption was also improved (P ≤ 0.05) by the same magnitude. However, feed conversion was not affected. There was no further response observed by adding protease to these diets. It is concluded that broiler chicks can tolerate up to 200 g kg−1 peas in their diets, with satisfactory performance at 400 g kg−1 provided CP and EAAs are supplied at 15% in excess of NRC requirements and addition of pectinase to pea-based diets improved weight gains and feed consumption.