Effects of increased dietary inclusion of yellow lupins and enzyme supplementation on performance, ileal digestibility of nutrients and microbial status of large intestine in broiler chickens

The experiment was carried out with Ross 308 broiler hybrids. One-day old chickens were allocated to six treatments, each treatment consisting of four replications with 50 birds each. The diets were based on cereal grains (wheat 31/35% and barley 25/30% in starter/grower diets, respectively), and contained 0, 5, 10% (starter) and 0, 10, 20% (grower) of yellow lupin seeds var. Juno. Each experimental diet was fed either unsupplemented or supplemented with enzymes (Ronozyme VP) at the level of 400 mg/kg. Performance was determined on days 21 and 42. Apparent ileal digestibility of nutrients and amino acids was determined in the period between days 21 to 28. At the end of experiment, carcass composition and number of Lactobacillus and Escherichia coli in the content of large intestine (rectum) were determined. In comparison to the diets without lupins, increased dietary content of yellow lupins slightly affected the body weight in the first period of chick growth. Enzyme supplementation did not show any significant influence. On day 42, the body weight decreased with increasing proportion of lupins; the highest body weight was observed in birds fed diets without lupins (2,546 g), then in animals fed the diets containing 5/10% lupins (2,512 g) and 10/20% of lupins (2,426 g). Effects of enzyme addition differed insignificantly. However, birds fed diets with enzymes were heavier (on average by 83 g) than control ones. All described differences were statistically significant for male chickens only. Enzyme supplementation and dietary lupin level did not influence feed and protein conversion. The apparent ileal digestibility of crude protein and ash was higher, when diets with increasing lupin content were supplemented with enzymes (P < 0.05). Both experimental factors had no significant effect on ileal digestibility of dry matter, crude fat and NFE. Increased lupins level and presence of carbohydrases resulted in significantly higher coefficients of ileal digestibility determined for Thr, Glu, Cys, Gly, Val, Ile, Leu, Lys and Arg. Regarding carcass composition, increasing dietary content of lupins negatively influenced the percentage of breast muscle (P < 0.01). For interaction lupins x enzymes the high P-values were calculated. Increased dietary content of lupins significantly decreased CFU numbers of E. coli and Lactobacillus spp., but enzyme addition reduced CFU of E coli and increased Lactobacillus proliferation (P < 0.01). The share of 5/10% of yellow lupine could be found as optimal level.