Ileal digestibility of energy and amino acids in three faba bean cultivars (Vicia faba L.) planted and harvested early or late in broiler chickens

Smit, M. N., R. F. Ketelaar, L. He, and E. Beltranena. 2021. Ileal digestibility of energy and amino acids in three faba bean cultivars (Vicia faba L.) planted and harvested early or late in broiler chickens. Poultry Science 100:101332. doi https://doi.org/10.1016/j.psj.2021.101332

broiler, cultivar, faba bean, frost damage, ileal digestibility, immature beans, peer-reviewed, Publication, Research Showcase 2021

PIP Author(s)

About

Publication Metrics

Locally grown faba bean represent an opportunity to poultry producers in temperate regions to reduce feed cost by replacing higher priced ingredients like imported corn grain and soybean meal. Suboptimal growing conditions can also result in a high percentage of immature beans at harvest time. Little is known about the effect of feeding frost damaged and immature beans on digestibility of gross energy (GE), crude protein (CP), and amino acids (AA) for broiler
chickens, yet pulse growers phase this harvest challenge almost every year. Therefore, the objective of this study was to compare the effect of feeding diets including different faba bean cultivars planted and harvested either EARLY (mostly ripen grain, no frost damage) or LATE (high proportion of immature beans, blackened hulls) on digestibility of GE, CP, and AA in broiler chickens.

Approach

To investigate, half of the seed of 2 zero-tannin cultivars (Snowbird and Snowdrop) and 1 low vicine and convicine cultivar (Fabelle) were planted at a single site either in early May and harvested in late September (EARLY) or planted in late May and harvested in late October (LATE). Diets of the 3 EARLY or LATE cultivars (95% inclusion) were fed to 756 broiler chickens (Ross 708) from d 15. Chickens were housed in 56 floor pens (13−14 birds/pen) in a 3 by 2 factorial arrangement (7 pens/diet). A nitrogen-free diet to correct for endogenous amino acid (AA) losses was fed to broilers in 14 pens from d 20. Ileal digesta was collected after euthanizing birds on day 23 or 24.

Analysis of Results

Planting and harvesting LATE vs. EARLY increased the proportion of immature beans from 5 to 64% for Snowbird, 7 to 79% for Snowdrop, and 22 to 80% for Fabelle. Planting and harvesting LATE vs. EARLY increased the proportion of frost-damaged beans from 20 to 83% for Snowbird, 36 to 88% for Snowdrop, and 5 to 29% for Fabelle. Planting and harvesting LATE vs. EARLY increased (P < 0.001) apparent ileal digestibility (AID) of gross energy (GE) by 45% and standardized ileal digestibility (SID) of CP by 13%. Planting and harvesting LATE vs. EARLY increased (P < 0.001) SID of AA by 11% except Cys. Snowbird and Snowdrop had greater (P < 0.05) SID of AA by 4.5% except Thr and Trp compared with Fabelle. Fabelle had 13% greater (P < 0.001) SID of Trp compared with Snowbird or Snowdrop. Results indicate that planting and harvesting LATE vs. EARLY increased GE, CP, and AA digestibility possibly by frost interrupting bean ripening on the field. Hull tannin content may have reduced the AA digestibility of Fabelle compared with Snowbird or Snowdrop.

Application

Compared with planting and harvesting faba beans at the recommended time for the region (early May), delaying planting and harvesting by 2 to 3 wk resulted in beans with greater proportions of frost-damaged (blackened) hull and immature grain (green and soft) cotyledons. Late planted and harvested faba bean had both lower condensed tannin and vicine and convicine content than early planted and harvested faba bean. Contrary to that expected, the results of this digestibility trial indicate that LATE vs. EARLY planting and harvesting faba bean increased GE, CP, and AA digestibility possibly by frost interrupting bean ripening on the field. Tannin content may have reduced the AA digestibility of Fabelle compared with Snowbird or Snowdrop faba bean cultivars.

Abstract

A concern of both pulse growers and poultry producers is how the timing of planting and harvesting affect the nutritional quality of faba bean for broiler chickens. To investigate, half of the seed of 2 zero-tannin cultivars (Snowbird and Snowdrop) and 1 low vicine and convicine cultivar (Fabelle) were planted at a single site either in early May and harvested in late September (EARLY) or planted in late May and harvested in late October (LATE). Diets of the 3 EARLY or LATE cultivars (95% inclusion) were fed to 756 broiler chickens (Ross 708) from d 15. Chickens were housed in 56 floor pens (13–14 birds/pen) in a 3 × 2 factorial arrangement (7 pens/diet). A nitrogen-free diet to correct for endogenous amino acid (AA) losses was fed to broilers in 14 pens from d 20. Ileal digesta was collected after euthanizing birds on day 23 or 24. Planting and harvesting LATE vs. EARLY increased the proportion of immature beans from 5 to 64% for Snowbird, 7 to 79% for Snowdrop, and 22 to 80% for Fabelle. Planting and harvesting LATE vs. EARLY increased the proportion of frost-damaged beans from 20 to 83% for Snowbird, 36 to 88% for Snowdrop, and 5 to 29% for Fabelle. Planting and harvesting LATE vs. EARLY increased (P < 0.001) apparent ileal digestibility (AID) of gross energy (GE) by 45% and standardized ileal digestibility (SID) of CP by 13%. Planting and harvesting LATE vs. EARLY increased (P < 0.001) SID of AA by 11% except Cys. Snowbird and Snowdrop had greater (P < 0.05) SID of AA by 4.5% except Thr and Trp compared with Fabelle. Fabelle had 13% greater (P < 0.001) SID of Trp compared with Snowbird or Snowdrop. Results indicate that planting and harvesting LATE vs. EARLY increased GE, CP, and AA digestibility possibly by frost interrupting bean ripening on the field. Hull tannin content may have reduced the AA digestibility of Fabelle compared with Snowbird or Snowdrop.