Inclusion of up to 20% Black Soldier Fly larvae meal in broiler chicken diet has a minor effect on caecal microbiota.

Background: The Black Soldier Fly larvae (BSFL) are a source of nutrients and bioactive compounds in broiler diets. Some components of the BSFL may serve as a prebiotic or may impact the intestinal microbiota of the broilers by other modes of action, which in turn can affect the health and performance of broilers. Here, we investigate the impact of up to 20% BSFL in broiler diets on the diversity and composition of the broiler's microbiota. Methods: Four hundred broilers were fed five iso-nutritious experimental diets with increasing levels of BSFL meal reaching 0%, 5%, 10%, 15%, 20% in the finisher diets. Eight caecal content samples coming from each of the eight replicates per treatment were collected at two time points (day 21 and day 42) for DNA extraction and sequencing of the V3-V4 regions using Illumina MiSeq 2 × 300 bp pair-end sequencing with 341f and 805r primers. Analysis of variance and Spearman's correlation were performed, while QIIME2, DADA2, and Calypso were used for data analysis. Results: When broilers were 21 days of age, the abundance of two groups of sequence variants representing Enterococcus and unclassified Christensenellaceae was significantly lower (p-value = 0.048 and p-value = 0.025, respectively) in the 20% BSFL group compared to the 0% BSFL group. There was no relevant alteration in the microbiota diversity at that stage. On day 42, the Spearman correlation analysis demonstrated that the sequence variants representing the genus Coprococcus showed a negative relationship with the BSFL inclusion levels (p-value = 0.043). The sequence variants representing the genus Roseburia and Dehalobacterium demonstrated a positive relationship with the BSFL dietary inclusion (p-value = 0.0069 and p-value = 0.0034, respectively). There was a reduction in the dissimilarity index (ANOSIM) caused by the 20% BSFL dietary inclusion. Conclusion: The addition of up to 20% BSFL in broiler diets did not affect the overall caeca microbiota diversity or composition at day 21. On day 42, there was a reduction in the beta diversity caused by the 20% BSFL dietary inclusion. The abundance of the bacterial group Roseburia was increased by the BSFL dietary inclusion, and it may be beneficial to broiler immunity and performance.

Determination of gastrointestinal passage rate using three different markers in laying hens.

The titanium dioxide (TiO2 ) marker technique is currently widely practiced as a method to evaluate gastrointestinal (GI) passage rate in poultry. However, this method requires sacrificing the animal to obtain digesta samples, is labour-intensive and eliminates the possibility of follow-up studies with the same individual. The aim of this study was to evaluate whether the radiographic methods barium-impregnated polyethylene spheres (BIPS) and barium sulphate (BaSO4 ) suspension are in agreement with the TiO2 technique and can be used as an alternative method for GI passage rate determination in laying hens. Whole-body radiographs were taken at different time points. Hens of group 3 (n = 55) were orally inoculated with 5 g of feed mixed with 0.15 g TiO2 , 5 hens per time point sacrificed, and whole gastrointestinal organs (crop, proventriculus, gizzard, small intestine and large intestine) were collected and analysed for TiO2 content. The average marker passage rate of hens administered BaSO4 was significantly faster than those administered BIPS (gizzard: 15.2 hr vs. 43.2 hr; small intestine: 15.2 hr vs. 38.4 hr, respectively). A greater percentage of BIPS remained in the crop at 0, 0.5, 2, 3 and 8 hr post-inoculation (p.i.) and in the gizzard at 2, 24, 36 and 48 hr p.i. (all p < 0.05) compared to TiO2 . In conclusion, the evaluation of the GI transit time is feasible using BIPS, TiO2 and BaSO4 . The evaluation of the GI transit time using BIPS and BaSO4 needs further investigation.