RESUMO
This study investigated the effects of CCHMA on growth performance, slaughter performance, serum biochemical indicators, intestinal morphology and microbiota of Zi goose. Initially, it was determined the optimal addition concentration of CCHMA to be 3 g/kg by the first feeding experiment. Then, 78 Zi geese were divided into control and CCHMA supplemented groups. The results showed that the body weight (BW) and average daily gain (ADG) of the CCHMA supplemented group was significantly increased (p < 0.05), and the feed/gain (F/G) of the CCHMA supplemented group was significantly decreased (p < 0.05) compared with the control group. The dressed yield percentage in the CCHMA supplemented group significantly increased by 0.78% (p < 0.05). Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were significantly lower in the CCHMA fed birds than in the control group (p < 0.05). Further, 16S rDNA gene sequencing conducted for cecal flora composition found that 3 g/kg CCHMA significantly increased the abundance of beneficial bacteria (CHKCI001, Colidextribacter and Subdoligranulum) (p < 0.05; p < 0.01) and suppressing harmful bacteria (Bacteroidetes and Methanobrevibacter) (p < 0.05) in the cecum of Zi goose. In conclusion, adding 3 g/kg of CCHMA in the diet can improve the growth performance, slaughter performance of Zi goose, and optimize the cecum microflora.
RESUMO
As an important parameter regulating soil carbon mineralization, microbial carbon use efficiency (CUE) is essential for the understanding of carbon (C) cycle in terrestrial ecosystems. Three nitrogen supplemental levels, including control (0 kg N·hm-2·a-1), low nitrogen (40 kg N·hm-2·a-1), and high nitrogen (80 kg N·hm-2·a-1), were set up in a Castanopsis fabri forest in the Daiyun Mountain. The basic physical and chemical properties, organic carbon fractions, microbial biomass, and enzyme activities of the soil surface layer (0-10 cm) were measured. To examine the effects of increasing N deposition on microbial CUE and its influencing factors, soil microbial CUE was measured by the 18O-labelled-water approach. The results showed that short-term N addition significantly reduced microbial respiration rate and the activities of C and N acquisition enzymes, but significantly increased soil microbial CUE. ß-N-acetyl amino acid glucosidase (NAG)/microbial biomass carbon (MBC), microbial respiration rate, ß-glucosidase (BG)/MBC, cellulose hydrolase (CBH)/MBC, and soil organic carbon content were the main factors affecting CUE. Moreover, CUE significantly and negatively correlated with NAG/MBC, microbial respiration rate, BG/MBC, and CBH/MBC, but significantly and positively correlated with soil organic carbon. In summary, short-term N addition reduced the cost of soil microbial acquisition of C and N and microbial respiration, and thus increased soil microbial CUE, which would increase soil carbon sequestration potential of the C. fabri forest.