Dynamic effects of black soldier fly larvae meal on the cecal bacterial microbiota and prevalence of selected antimicrobial resistant determinants in broiler chickens.

BACKGROUND: We had earlier described the growth-promoting and -depressive effects of replacing soybean meal (SBM) with low (12.5% and 25%) and high (50% and 100%) inclusion levels of black soldier fly larvae meal (BSFLM), respectively, in Ross x Ross 708 broiler chicken diets. Herein, using 16S rRNA gene amplicon sequencing, we investigated the effects of replacing SBM with increasing inclusion levels (0-100%) of BSFLM in broiler diets on the cecal bacterial community composition at each growth phase compared to broilers fed a basal corn-SBM diet with or without the in-feed antibiotic, bacitracin methylene disalicylate (BMD). We also evaluated the impact of low (12.5% and 25%) inclusion levels of BSFLM (LIL-BSFLM) on the prevalence of selected antimicrobial resistance genes (ARGs) in litter and cecal samples from 35-day-old birds. RESULTS: Compared to a conventional SBM-based broiler chicken diet, high (50 to100%) inclusion levels of BSFLM (HIL-BSFLM) significantly altered the cecal bacterial composition and structure, whereas LIL-BSFLM had a minimal effect. Differential abundance analysis further revealed that the ceca of birds fed 100% BSFLM consistently harbored a ~ 3 log-fold higher abundance of Romboutsia and a ~ 2 log-fold lower abundance of Shuttleworthia relative to those fed a BMD-supplemented control diet at all growth phases. Transient changes in the abundance of several potentially significant bacterial genera, primarily belonging to the class Clostridia, were also observed for birds fed HIL-BSFLM. At the finisher phase, Enterococci bacteria were enriched in the ceca of chickens raised without antibiotic, regardless of the level of dietary BSFLM. Additionally, bacitracin (bcrR) and macrolide (ermB) resistance genes were found to be less abundant in the ceca of chickens fed antibiotic-free diets, including either a corn-SBM or LIL-BSFLM diet. CONCLUSIONS: Chickens fed a HIL-BSFLM presented with an imbalanced gut bacterial microbiota profile, which may be linked to the previously reported growth-depressing effects of a BSFLM diet. In contrast, LIL-BSFLM had a minimal effect on the composition of the cecal bacterial microbiota and did not enrich for selected ARGs. Thus, substitution of SBM with low levels of BSFLM in broiler diets could be a promising alternative to the antibiotic growth promoter, BMD, with the added-value of not enriching for bacitracin- and macrolide-associated ARGs.

Growth performance, organ weight, and plasma metabolites in broiler chickens fed corn-soybean meal diet containing berry pomaces and fed without or with multienzymes supplement.

This study evaluated effects of feeding low-bush wild blueberry (LBP) and organic American cranberry (CRP) pomaces without or with multienzyme supplement (ENZ) on growth performance, organ weight and plasma metabolites in broiler chickens. Nonenzyme-fed (no-ENZ: n = 1,575) and enzyme-fed (ENZ: n = 1,575) day-old male Cobb500 broilers were placed in floor pens (45 chicks/pen) and allocated to five corn-soybean meal-based diets: a basal diet supplemented with either bacitracin methylene disalicylate (BMD, 55 mg/kg), 0.5 or 1% of CRP or LBP in a 2 × 5 factorial design for 35-day experiment. Body weight (BW), feed intake (FI) and mortality were recorded whereas BW gain (BWG) and feed conversion ratio (FCR) were calculated. Birds were sampled at days 21 and 35 for organ weights and plasma metabolites. There were no interactions between diet and ENZ on any parameter (P > 0.05) and no effect of ENZ on overall (d 0-35) growth performance and organ weights (P > 0.05). Birds fed BMD were heavier (P < 0.05) at d 35 and had better overall FCR than berry-supplemented birds. Birds fed 1% LBP had poor FCR than birds fed 0.5% CRP. Birds fed LBP exhibited heavier liver (P < 0.05) than birds fed BMD or 1% CRP. The highest plasma concentrations of aspartate transaminase (AST), creatine kinase (CK) at d 28 and gamma-glutamyl transferase (GGT) at d 35 were found in ENZ-fed birds (P < 0.05). At d 28, birds fed 0.5% LBP showed higher plasma AST and CK concentrations (P < 0.05). However, CRP feeding resulted in a lower plasma CK level compared with BMD feeding (P < 0.05). The lowest cholesterol level was detected in 1% CRP-fed birds. In conclusion, this study showed no ENZ effects to potentiate berry pomaces on the overall growth performance of broilers (P < 0.05. However, plasma profiles revealed the potential of ENZ to modulate the metabolism of pomace-fed broilers. LBP increased BW during the starter phase, while CRP increased BW during the grower phase.

Effects of partial or complete replacement of soybean meal with commercial black soldier fly larvae (Hermetia illucens) meal on growth performance, cecal short chain fatty acids, and excreta metabolome of broiler chickens.

Black soldier fly larvae meal (BSFLM) is receiving great attention as a rich source of protein and antimicrobials for poultry. Therefore, we evaluated the effects of partially or completely replacing soybean meal (SBM) with commercial BSFLM on growth performance, tibia traits, cecal short chain fatty acid (SCFA) concentrations, and excreta metabolomes in broiler chickens (Gallus gallus domesticus). A total of 480 day-old male Ross × Ross 708 chicks were assigned to 6 diets (8 replicates/diet): a basal corn-SBM diet with in-feed bacitracin methylene disalicylate (BMD), a corn-SBM diet without BMD (0% BSFLM), and four diets in which the SBM was substituted with 12.5, 25, 50, and 100% BSFLM. Body weight (BW), feed intake (FI) and cumulative feed conversion ratio (cFCR) were monitored on days 14, 28, and 35. Cecal SCFA levels were determined on days 14, 28, and 35. Tibia traits and excreta metabolomes were determined on day (d) 35. On d14, birds fed 12.5 and 25% BSFLM had a similar BW, FI, and cFCR as birds fed BMD (P > 0.05). On d 35, birds fed 12.5% BSFLM had a similar BW, FI and cFCR as birds fed BMD or 0% BSFLM (P > 0.05). For each phase, birds fed 100% BSFLM had a lower BW, FI and higher cFCR than birds fed BMD or 0% BSFLM (P < 0.05). On d 35, BW decreased linearly, quadratically, and cubically with increasing levels of BSFLM (P < 0.01). Overall (d 0-35), BSFLM linearly, quadratically, and cubically decreased FI and quadratically and cubically increased cFCR (P < 0.01). Quadratic responses were observed for tibia fresh weight (P = 0.049) and ash content (P = 0.022). BSFLM did not impact cecal SCFAs levels. The excreta metabolome of birds fed 100% BSFLM clustered independently from all other groups and exhibited greater levels of putatively identified methionine, lysine, valine, glutamine, histidine and lower levels of arginine as compared to all diets. Taken together, substitution of SBM with ≤25% of BSFLM in the starter phase may be used as an alternative to BMD.

Complete replacement of soybean meal with black soldier fly larvae meal in feeding program for broiler chickens from placement through to 49 days of age reduced growth performance and altered organs morphology.

Black soldier fly larvae meal (BSFLM) is characterized with good nutritional and functional attributes. However, there is limited data on inclusion of BSFLM in broiler chicken rations from placement through to market weight. Therefore, we examined growth and organ responses of partial to complete replacement of soybean meal (SBM) with BSFLM in a practical feeding program. A total of 1,152 d-old male Ross × Ross 708 chicks were allocated to 48 pens and assigned one of six diets (n = 8). The diets were: a basal corn-SBM diet (0%BSFLM), 4 diets in which SBM in 0%BSFLM was replaced with BSFLM at 12.5, 25, 50, and 100% and a final diet (0 + AGP) in which 0%BSFLM was treated with coccidiostat (70 mg Narasin/kg) and antibiotic (55 mg Bacitracin Methylene Disalicylate/kg). For energy fortification, soy oil was used for 0%BSFLM diets and black soldier fly oil in the other diets. Body weight, feed intake (FI), BW gain (BWG), and mortality-corrected feed conversion ratio (FCR) were reported. Organ weights were recorded on d 24 and 49. On d 10, birds fed diets 12.5, 25, and 0 + AGP had higher BWG than birds fed diets 0, 50, and 100 (P < 0.01), and birds fed diet 100 had lower BWG than birds fed diets 0 or 50 (P < 0.01). Birds fed diets 50 and 100 had lower BWG than birds fed all other diets on d 24 and 49 (P < 0.05). Overall (d 0-49), BSFLM linearly (P < 0.01) decreased BW, BWG, and FI and increased FCR and mortality. The overall BWG of 50 and 100% BSFLM birds was 92 and 81% of birds fed 0%BSFLM, repectively and coresponding overall FI was 96 and 90%. An increase in gizzard, small intestine, pancreas, and liver relative weights were observed with increasing BSFLM inclusion (P < 0.01). The data indicated that lower levels of BSFLM could provide some growth-promoting effects commensurate to antibiotics in the starter phase. However, replacing SBM with greater amounts (≥50) of BSFLM reduced growth and increased organ size.

Research Note: Effects of supplementing cranberry and blueberry pomaces on meat quality and antioxidative capacity in broilers.

Cranberry and blueberry pomaces are rich in antimicrobial and antioxidant compounds. They have been identified as potential antibiotic alternatives in animal feed, but their antioxidative capacity for maintaining or improving the meat quality in broilers is not well documented. This study was to determine whether cranberry and wild blueberry pomaces in diets could positively influence the broiler meat quality. A total of 3,150 broilers were randomly allotted to 10 dietary treatments with bacitracin methylene disalicylate, wild cranberry pomace (CRP) (0.5 and 1% of the basal diet), and wild blueberry pomace (BLP) (0.5 and 1% of the basal diet) alone or in combination with a mixture of feed enzymes. The results showed that supplementation with the CRP or BLP did not affect meat lightness and yellowness, while the deeper red meat (higher a∗ values) was observed in the birds receiving the diet containing 0.5% BLP against those in CRP treatments (P = 0.015). In addition, inclusion of CRP or BLP in the diet did not change meat texture and proximate composition (moisture, protein, fat, ash) irrespective of pomace concentrations. Although there were no obvious effects of CRP or BLP supplementation on meat antioxidant capacity and the incidence of myopathies (P > 0.05), the upward trend of antioxidant capacity and less severity of woody breast were observed in birds fed with 0.5% CRP. Furthermore, supplementation of 0.5 or 1.0% CRP without the enzyme resulted in higher mRNA levers of Nrf, Gpx2, and HO-1 (P < 0.05). Taken together, 0.5% CRP supplementation without the enzyme could potentially maintain meat quality and attenuate the severity of woody breast.