Comparison of standardized ileal digestibility of amino acids in faba beans and field peas in broiler chickens and pigs.

An experiment, using the same set of five diets was conducted to determine and compare the standardized ileal digestibility (SID) of amino acids (AA) in faba beans and three cultivars of field peas in broiler chickens and pigs. Four test diets were prepared to contain faba beans, DS-Admiral field peas, Hampton field peas, or 4010 field peas as the sole source of nitrogen. A nitrogen-free diet (NFD), as the fifth diet, was prepared to estimate the basal endogenous losses of AA to determine the SID of AA in the test ingredients. A total of 416 male broiler chickens with an initial body weight (BW) of 951 ± 111 g were allotted to five diets in a randomized complete block design with BW as a blocking factor on day 21 posthatching. There were 8 replicate cages with 10 birds per cage for diets containing test ingredients and 12 birds per cage for NFD. All birds were allowed ad-libitum access to feed for 5 days. On day 26 posthatching, all birds were euthanized by CO2 asphyxiation and digesta contents were collected from the distal two-thirds of the ileum. Twenty barrows with an initial BW of 30.2 ± 1.58 kg, surgically fitted with T-cannulas in the distal ileum, were divided into four blocks according to BW and each block was assigned to a 5 × 2 incomplete Latin Square design that consisted of five dietary treatments and two experimental periods. For each experimental period, there was a 5-day adaptation period followed by a 2-day collection of ileal digesta samples. The data were analyzed as a 2 × 4 factorial treatment arrangement with the effect of species (i.e., broiler chickens and pigs) and test diets (i.e., four test ingredients). For broiler chickens, the SID of Lys in faba beans, DS-Admiral field peas, and Hampton field peas were above 90% but in 4010 field peas, it was 85.1%. The SID of Lys in faba beans, DS-Admiral field peas, and Hampton field peas for pigs was above 80% but was 78.9% in 4010 field peas. The respective SID of Met in faba beans, DS-Admiral field peas, Hampton field peas, and 4010 field peas were 84.1%, 87.3%, 89.8%, and 72.1% for broiler chickens, and 71.5%, 80.4%, 81.8%, and 68.1% for pigs. The SID of AA in 4010 field peas was the least (P < 0.05) for chickens, but in pigs, it was comparable with faba beans. In conclusion, the SID of AA in faba beans and field peas was greater in broiler chickens compared with pigs and there was a cultivar effect.