Effect of black soldier fly larvae fat inclusion in the diet on the performance and caecal bacterial diversity of broiler Japanese quails (Coturnix japonica)

In this thesis, a total of 100 Japanese quails (Coturnix japonica), were randomly divided into 4 groups. A basal diet containing corn oil (CO) as added fat served as control group was tested against 3 experimental diets where CO was partially substituted by black soldier fly (BSF) larvae fat by 25%, 50% and 100% (BSFO 25, BSFO 50 and BSFO 100 respectively). The objective was to evaluate if this substitution could be beneficial to quails’ growth performance, slaughter traits and caecal bacterial diversity. During the whole rearing period, there were no obvious significances in the growth performance parameters such as feed intake (FI), average weekly gain (AWG) and feed conversion ratio (FCR), with the exception of an improvement in the FCR in last week of rearing (35-42 days) for the diets in which BSFO was included but not significantly (C: 2.55; BSFO 25:2.47; BSFO 50: 2.48; BSFO 100: 2.47). For the selected internal organs weights and gastrointestinal segments lengths no significant differences were found between all dietary treatments. A total of 10 quails per group were randomly picked, and the caecal content was obtained. Bacterial structure was examined by high-throughput sequencing using the V4–V5 region of the 16S rRNA gene. The Alpha diversity measurements showed a lower diversity richness and evenness in the samples of quails fed with a total inclusion of H. illucens fat. Beta diversity measurements showed statistical dissimilarities between the studied groups mainly the BSFO 100 group compared to the control animals. Firmicutes were the dominant phylum in all the groups and the core bacteria at genus level was composed by Subdoligranulum, Unclassified genus within family Lachnospiraceae, Blautia, CHKCI001 and Streptococcus. Linear discriminant analysis with effect size (LEfSe) showed significant differences between the control group and the others 3 experimental groups. The most significant differences were found by comparing the control group to the BSFO 100 group. A total of 16 significantly different taxa were found. Notably, the relative abundance of Actinobacteria, Coriobacteriia, Coriobacteriales, Eggerthellaceae, Erysipelotrichia, Erysipelotrichales, Erysipelotrichaceae, Eubacterium brachy group, Anaerotruncus, Negativibacillus, Coprococcus 3, Anaerostipes, Lachnoclostridium and Bacillus were significantly higher in the control group. On the other hand, in the BSFO 100 group, the genera Fusicatenibacter and Subdoligranulum were significantly enriched. The results suggest that insect fat influences the caecal bacteria of quails and can substitute the conventionally used oil sources in poultry diets such as corn oil.

In this thesis, a total of 100 Japanese quails, were divided into 4 groups. A basal diet containing corn oil as added fat served as control group was tested against 3 experimental diets where it was partially substituted by black soldier fly larvae fat (BSFO) by 25%, 50% and 100%. The objective was to evaluate if this substitution could be beneficial to quails’ growth performance, slaughter traits and caecal bacterial diversity. During the whole rearing period, there were no significances in the growth performance parameters such as feed intake, average weekly gain and feed conversion ratio. For the selected internal organs weights and gastrointestinal segments lengths no significant differences were found between all dietary treatments. 10 quails per group were randomly picked, and the caecal content was obtained. Bacterial structure was examined by high-throughput sequencing using the V4–V5 region of the 16S rRNA gene. The Alpha diversity measurements showed a lower richness and evenness in the samples of quails fed with a total inclusion of insect fat. Beta diversity measurements showed statistical dissimilarities between the studied groups mainly the BSFO 100 group compared to the control animals. Firmicutes were the dominant phylum in all the groups. The core bacteria at genus level were Subdoligranulum, Unclassified genus within family Lachnospiraceae, Blautia, CHKCI001 and Streptococcus. Linear discriminant analysis with effect size showed significant differences between the control group and the others 3 experimental groups. The most significant differences were found by comparing the control group to the BSFO 100 group with a total of 16 significantly different taxa. The results suggest that insect fat influences the caecal bacteria of quails and can partially substitute the conventionally used oil sources in poultry diets such as corn oil