Feeding different cultivars and quality levels of faba bean to broiler chickens.

Abstract

A concern of both pulse growers and poultry producers is how frost damage around harvest time affects the nutritional quality of faba bean for broiler chickens. To investigate, two zero-tannin cultivars (Snowbird, Snowdrop) and one low vicine and convicine cultivar (Fabelle) sourced from seed growers were spring planted 3 weeks later than recommended (mid-May) and harvested late October to purposely increase frost damage. Parent, certified seed (high quality), and harvested frost damaged beans (low quality) of the three cultivars were fed to 740 chickens housed in 64 floor pens in a 2 × 3 factorial plus control (9 pens of 11 or 12 birds per treatment). Starter (d 0 to 11), grower (d 12 to 24), and finisher (d 25 to 40) diets included 15%, 30%, and 45% faba bean in partial (starter, grower) or total replacement of soybean meal (SBM; control). Harvested Snowbird, Snowdrop, Fabelle averaged 52%, 62%, 17% blackened hull and 35%, 43%, 51% immature beans, respectively. There was a cultivar × quality interaction (P < 0.05) on daily feed disappearance (ADFI) and gain-to-feed (G:F). Broilers fed low-quality Snowdrop consumed 10 g/d more finisher and 6 g/d more feed overall than those fed low-quality Snowbird or Fabelle; broilers fed parent seed were intermediate. Feeding low-quality Fabelle resulted in best overall G:F (0.646) versus high-quality Snowbird (0.611), high-quality Fabelle (0.624), or low-quality Snowdrop (0.624). Average daily weight gain (ADG) and bird body weight (BW) at the end of each growth phase were not affected by cultivar or quality level. Controls fed SBM only grew 2.75 g/d faster overall and were 113.5 g heavier at the end of the trial than broilers fed faba bean (P < 0.05). Controls fed SBM only had 0.024 g/g better overall G:F than broilers fed faba bean (P < 0.05). Feeding low-quality beans or high-quality seed had no effect on antemortem BW, chilled carcass weight (WT), dressing percentage or yield of saleable cuts except that broilers fed Snowbird or Snowdrop had 0.8%-unit larger thighs than those fed Fabelle. Controls fed SBM only were 110 g heavier at slaughter, had 72 g heavier chilled carcass WT, and 0.5%-unit greater dressing percentage than broilers fed faba bean (P < 0.05). These results indicate that feeding frost damaged and(or) immature faba bean, to the extent observed in this trial, did not negatively affect growth performance or carcass attributes of broiler chickens compared to feeding parent, certified, high-quality seed of these cultivars.