Effects of soybean meal replacement with fermented alfalfa meal on the growth performance, serum antioxidant functions, digestive enzyme activities, and cecal microflora of geese

Abstract

Fermented forages are important feedstuffs. Bacillus subtilis inoculants are often used to improve the value of forage legume fermentation. The present work was conducted to study the effects of replacing soybean meal with solid-state fermented alfalfa meal (FAM) with B. subtilis ACCC 01746 on growth performance, serum antioxidant and digestive enzyme activities, and cecal microflora in goose. 300 healthy geese with similar body weights were randomly assigned to six treatment groups with five replicates of 10 geese (five males and five females) each. Geese were fed ad libitum for 35 days. Results showed that the geese fed with 4 and 8% FAM exhibited no significant effects on their final body weights (FBW) and average day gain (ADG) (P>0.05), whereas 12% or higher FAM caused poor growth of the geese compared with control diet (linear (L): P<0.05). The average daily feed intake (ADFI) (quadratic (Q): P<0.05) and feed conversion ratio (FCR) (L: P<0.05) with 8% or higher supplementation level were higher than those of the control group. The activities of antioxidant enzyme in serum increased, and the level of malondialdehyde (MDA) significantly decreased with increasing dietary FAM level (L: P<0.05). However, no significant differences were observed at 8% or lower supplementation level for glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) (P>0.05) and at 4% for catalase (CAT) supplementation level compared with the control group. All diets containing FAM increased digestive enzyme activities in geese. However, geese fed diets with 12% FAM supplementation showed the highest trypsin activities in pancreas (Q: P<0.05). Supplementation with 12% or higher FAM significantly increased amylase activities in pancreas (L: P<0.05) and duodenum (L: P<0.05) compared with the control group. Significant differences were not observed in total anaerobic bacteria between geese fed with FAM and control diets on day 35 (P>0.05). The numbers of Bifidobacterium and Lactobacillus in the cecum of geese fed with FAM significantly increased (L: P<0.05), but no significant effects were found with 4 and 8% FAM supplementation levels compared with the control (P>0.05). By contrast, the coliform counts of cecum decreased with increasing inclusion of FAM, but these counts were significantly reduced in geese fed diets with 12% or higher FAM supplementation level (L: P<0.05). Collectively, our results indicated that supplementation of the basal geese diet with 8% FAM had no apparent adverse effects on growth performance, serum antioxidant enzyme activities, and digestive parameters and beneficial microbiota.