The nutritional value of zero-tannin faba bean for grower-finisher pigs

Abstract

The nutrient profile of zero-tannin faba bean and its effects on performance and carcass characteristics of grower-finisher pigs was investigated. In exp. 1, chemical characteristics were analyzed. Faba bean contained (as fed) 27.5% crude protein (CP), 1.75% lysine, 0.88% threonine, and 0.21% methionine. Twelve 55-kg barrows were fitted with an ileal cannula and fed twice daily at 3 x maintenance either a 96% faba bean diet or a 62% faba bean diet containing cornstarch to measure apparent total tract energy and ileal amino acid (AA) digestibility, respectively, and calculate standardized ileal digestible (SID) AA and net energy (NE) content. After a 6-d acclimation, faeces were collected for 2 d and ileal digesta for 2 d. Apparent total tract energy digestibility, and digestible energy and NE content were 88.5%, and 3.47 and 2.27 Mcal kg-1 (as fed), respectively. Apparent ileal digestibility was 85.9, 76.1, and 74.1%, and SID AA content was 1.54, 0.70, and 0.16% (as fed), for lysine, threonine, and methionine, respectively. In exp. 2, 100 grower pigs in 20 pens were fed either a soybean or faba bean-based diet regimenfrom 35 to 115 kg. Diets were formulated to equal NE and SID [Grower (35 to 60 kg), 2.40/3.95; Finisher 1 (60 to 90 kg), gilts 2.38/3.15, barrows 2.38/2.76; Finisher 2 (90 to 115 kg), gilts 2.38/2.92, barrows 2.35/2.55; Mcal kg-1 NE/g SID lysine Mcal-1 NE, respectively] using determined NE and SID values for faba bean. Pigs were weighed, feed intake was measured, and carcass measurements were obtained. From 35 to 115 kg, average daily feed intake (ADFI; 2.58 and 2.56 kg d-1, respectively) and gain (0.96 and 0.98 kg d-1) did not differ between faba bean and soybean meal. Feed efficiency was 0.02 higher for soybean meal than for faba bean in the Grower phase (P < 0.05). At slaughter, back fat thickness did not differ; however, loin depth was 4.0 mm thicker for soybean meal than for faba bean (P < 0.05). In summary, zero-tannin faba bean has an attractive nutrient profile and does not alter ADFI or average daily gain (ADG) of grower-finisher pigs at inclusion rates up to 30%.The reduced feed efficiency in the Grower phase and reduced lean thickness for pigs fed faba bean indicate that dietary AA supply might have been limiting for the faba bean diets early in the study. In conclusion, the zero-tannin faba bean is a worthwhile energy and protein feedstuff to consider in swine feed formulation. Key words: Digestibility, energy, faba bean, growth performance, nutritional value, pig