Effects of graded fiber level and caecectomy on metabolizable energy value and amino acid digestibility in geese

This study was carried out to evaluate the effects of graded levels of fiber from rice hull and the caecectomy on metabolizable energy（ME） and amino acid digestibility（AAD） in 42 Wuzong geese（21 intact and 21 caecectomized）. The experiment was a 3×2 factorial randomized design with 3 fiber levels and 2 treatments of geese（caecectomized and intact）. Each of the 3 diets was tube-fed（60 g） to 7 caecectomized and 7 intact adult Wuzong geese that had been fasted for 24 h. Excreta were collected for the next 48 h. The same geese were also fasted for estimation of endogenous losses of amino acids（AA） and energy after short period recovery. AA content and metabolizable energy value were determined in the excreta. In general, significant effects were found for fiber levels on apparent digestibility of Thr, Leu, Pro, Glu,Val, Ala and total AA（P〈0.05）. Apparent metabolizable energy（AME） and true metabolizable energy（TME） were both significantly influenced by increased fiber levels（P〈0.01）. Compared with caecectomized geese, markedly increases of AME and TME were found in intact geese（P〈0.01 for AME and P 〈0.05 for TME）, but no difference in the AAD were found between intact and caecectomized geese（P〉0.05）, except for Lys and Try（P〈0.05）. These observations suggested that dietary fiber level played an important role in digestibility of AAD and ME. Intact geese should be chosen for the nutrient evaluation of feedstuffs in practice, resulting from the significant difference between caecectomized and intact geese.

Effect of Bacillus subtilis and Bacillus licheniformis supplementation in diets with low-and high-protein content on ileal crude protein and amino acid digestibility and intestinal microbiota composition of growing pigs

Background： Bacillus spp. seem to be an alternative to antimicrobial growth promoters for improving animals＇ health and performance. However, there is little information on the effect of Bacillus spp. in combination with different dietary crude protein（CP） levels on the ileal digestibility and microbiota composition. Therefore, the objective of this study was to determine the effect of Bacillus spp. supplementation to low-（LP） and high-protein diets（HP） on ileal CP and amino acid（AA） digestibility and intestinal microbiota composition.Methods： Eight ileally cannulated pigs with an initial body weight of 28.5 kg were randomly allocated to a rowcolumn design with 8 pigs and 3 periods of 16 d each. The assay diets were based on wheat-barley-soybean meal with two protein levels： LP（14% CP, as-fed） and HP diet（18% CP, as-fed）. The LP and HP diets were supplemented with or without Bacil us spp. at a level of 0.04%（as-fed）. The apparent ileal digestibility（AID） and standardized ileal digestibility（SID） of CP and AA was determined. Bacterial community composition from ileal digesta was analyzed by Illumina amplicon sequencing and quantitative real-time PCR. Data were analyzed as a 2 × 2 factorial design using the GLIMMIX procedures of SAS.Results： The supplementation with Bacillus spp. did not affect both AID and SID of CP and AA in growing pigs.Moreover, there was no difference in AID of CP and AA between HP and LP diets, but SID of cystine, glutamic acid,glycine, and proline was lower（P 〈 0.05） in pigs fed the HP diets. The HP diets increased abundance of Bifidobacterium spp. and Lactobacillus spp.,（P 〈 0.05） and by amplicon sequencing the latter was identified as predominant genus in microbiota from HP with Bacillus spp., whereas dietary supplementation of Bacillus spp. increased（P 〈 0.05） abundance of Roseburia spp.Conclusions： The HP diet increased abundance of Lactobacillus spp. and Bifidobacterium spp.. The supplementation of Bacil us spp. resulted in a higher abundance of healthy gut associated bacteria without affecting ileal CP and AA digestibility, whereas LP diet may reduce the flow of undigested protein to the large intestine of pigs.