Lactobacilli counts in crop,ileum and caecum of growing broiler chickens fed on practical diets containing whole or dehulled sweet lupin (Lupinus angustifolius) seed meal

1. Four experiments with growing broiler chickens were carried out to study the effects of the inclusion in their diets of lupin (Lupinus angustifolius ) seed meal on E. coli and lactobacilli counts in crop, ileum and caeca at 3 or 4 weeks of age. 2. Diets were formulated to contain the same amounts of metabolisable energy (12.55 MJ/kg) and protein (210 g/kg). Raw whole (heat-untreated) or dehulled sweet (low in alkaloids) lupin seed meal (400 and 320 g/kg respectively) were used to prepare the lupin-based diets, whose protein content was completed with either defatted soyabean meal or casein. 3. Final body weight and food intake of chickens fed on whole lupin seed meal diets were lower than controls, but gain: food ratios were not different. However, birds given the diet with dehulled lupin seed meal had similar body weight, food intake and gain: food values as those of controls. 4. While E. coli counts were not affected, lactobacilli numbers were consistently increased compared to controls in all intestinal sections of chickens fed on the whole or dehulled lupin-based diets, irrespective of the age of the birds or the presence of soyabean meal or casein in the diet. The lactobacilli species isolated were: Lactobacillus fermentum, L. acidophilus, L. salivarius and L. brevis 5. The results suggest that the use of whole or dehulled sweet lupin seed meal in diets for growing broilers might enhance the growth of lactic acid-fermenting bacteria in the gut.