8:30 am - 9:30 am
A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES MSc Final Exam Seminar by Protus Nyende. This seminar is open to the general public to attend.
Meeting ID: 938 8336 3302
Thesis Topic: Nutritional value of faba bean cultivars as sources of energy and protein for weaned and growing pigs
MSc with Dr. Ruurd Zijlstra
Novel faba bean cultivars vary in nutrient content, digestibility and antinutritional factors that must be characterized to prioritize which faba bean cultivars to grow for pig feeding. In chapter 2, five diets included (20%, phase 1; 30%, phase 2) 3 different, zero-tannin and high vicine/covicine faba bean cultivars (Snowbird, Snowdrop and Tabasco) and 2 medium tannin cultivars (Fabelle, low vicine/covicine; Malik, high vicine/covicine). Diets were fed to weaned pigs to investigate their effect on nutrient digestibility and growth performance. Fabelle contained the most condensed tannins (CT; 0.53%) but the least vicine (0.4%) and covicine (0.1%). Zero-tannin cultivars contained little CT (< 0.2%) but had the greatest vicine (averaged 0.5%) and covicine content (0.4%). For phase 1, energy and nutrient digestibility and growth performance did not differ among cultivar diets. For phase 2, diet apparent total digestibility (ATTD) of energy and CP was greatest (P < 0.05) for Snowdrop and Tabasco, and lowest in Malik and intermediate for Snowbird or Fabelle. Diet net energy (NE) values was greater (P < 0.05) for Tabasco than Snowbird, Fabelle and Malik and intermediate for Snowdrop. For the entire trial (day 0 to 28), the average daily feed disappearance (ADFD) was 10% greater (P < 0.05) in pigs fed Fabelle than Malik and intermediate in pigs fed Snowbird, Snowdrop or Tabasco. Consequently, pigs fed Fabelle diet had the greatest (P < 0.05) average daily gain (ADG) and final body weight (BW). In Chapter 3, two zero-tannin (Snowbird and Snowdrop) and 2 mid-tannin (Fabelle and Florent, high vicine/covicine) cultivars were included in 4 diets at 95%. Diets were fed to 8 ileal-cannulated barrows (37.5 kg) for four 9-day periods in a 4 × 4 Latin square. A nitrogen-free diet was also fed to correct for basal endogenous losses of protein and amino acids. The analysed tannins content was double in mid-tannin cultivars than zero-tannin cultivars (14 vs. 6.9 g/kg). Vicine/covicine was lowest in Fabelle (0.6 g/kg vicine; 0.4 g/kg covicine) but greatest in Snowbird, Snowdrop and Florent (5.5 to 7.0 g/kg vicine; 3.4 g/kg covicine). Apparent total tract digestibility of dry matter and gross energy was greatest (P < 0.05) in pigs fed Snowbird, intermediate for Snowdrop and Fabelle, and lowest for Florent. Apparent ileal digestibility (AID) of starch was greater (P < 0.05) in zero- than mid-tannin cultivars. Ingredient NE values were greatest in pigs fed Snowbird and did not differ among Snowdrop and Fabelle or Florent. The standardised ileal digestibility coefficient (CSID) of crude protein was greater in Fabelle than Snowbird, Snowdrop and Florent, with similar differences for lysine and most essential amino acids.
In conclusion, Fabelle with mid-tannin but the least vicine and convicine content, was greatest in growth performance in weaned pigs, intermediate in energy but not different in protein or amino acid digestibility from zero-tannin cultivars. Combined mid-tannin and, vicine and covicine possibly contributed to both lower energy and nutrient digestibility in pigs fed Malik and Florent than zero-tannin cultivars. Cultivar variation in content of macronutrients including total and resistant starch, crude protein and dietary fibre contributed to difference in energy, protein and amino acid digestibility and should be considered in diet formulation.