Supplementation of lactobacillus-fermented rapeseed meal in broiler diet reduces Campylobacter jejuni cecal colonization and limits the l-tryptophan and l-histidine biosynthesis pathways.

BACKGROUND: Campylobacter jejuni (C. jejuni), a widely distributed global foodborne pathogen, primarily linked with contaminated chicken meat, poses a significant health risk. Reducing the abundance of this pathogen in poultry meat is challenging but essential. This study assessed the impact of Lactobacillus-fermented rapeseed meal (LFRM) on broilers exposed to C. jejuni-contaminated litter, evaluating growth performance, Campylobacter levels, and metagenomic profile. RESULTS: By day 35, the litter contamination successfully colonized broilers with Campylobacter spp., particularly C. jejuni. In the grower phase, LFRM improved (P < 0.05) body weight and daily weight gain, resulting in a 9.2% better feed conversion ratio during the pre-challenge period (the period before artificial infection; days 13-20). The LFRM also reduced the C. jejuni concentration in the ceca (P < 0.05), without altering alpha and beta diversity. However, metagenomic data analysis revealed LFRM targeted a reduction in the abundance of C. jejuni biosynthetic pathways of l-tryptophan and l-histidine and gene families associated with transcription and virulence factors while also possibly leading to selected stress-induced resistance mechanisms. CONCLUSION: The study demonstrated that LFRM inclusion improved growth and decreased cecal Campylobacter spp. concentration and the relative abundance of pivotal C. jejuni genes. Performance benefits likely resulted from LFRM metabolites. At the molecular level, LFRM may have reduced C. jejuni colonization, likely by decreasing the abundance of energy transduction and l-histidine and l-tryptophan biosynthesis genes otherwise required for bacterial survival and increased virulence. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Growth performance, caecal microbiome profile, short-chain fatty acids, and litter characteristics in response to placement on reused litter and combined threonine, arginine and glutamine supplementation to juvenile male broiler chickens.

BACKGROUND: Exposure of broilers to litter microbiome may increase specific amino acid (AA) requirements towards activated immune responses. This may challenge the generality of the ideal protein (IP) concept, in which dietary essential AA to lysine ratios aimed to mimic presumably constant AA to lysine ratios in whole bird requirements. Therefore, we tested the effect of threonine, arginine and glutamine (TAG) supplementation to IP-based control diets (C) on performance, caecal microbiome composition, short-chain fatty acids and litter characteristics of broiler chickens placed on reused litter. RESULTS: Thirty-two pens with ten male broiler chickens each were used in a 2 × 2 factorial arrangement of two diet treatments (with or without TAG supplementation) and two litter treatments (placement on clean or reused litter) for 21 days (n = 8). Caecal contents were analysed for microbiome profile using percent guanine + cytosine (%G + C profile) method and short chain fatty acids. TAG-supplemented birds underperformed compared to C birds (P = 0.002), whereas birds placed on reused litter outperformed those on clean litter (P = 0.047). Diet, reused litter and their interaction impacted the %G + C profile at different ranges. Whilst TAG supplementation reduced bacterial abundance at %G + C 51-56 (P < 0.05), reused litter placement tended to reduce %G + C 23-31 and increase %G + C 56-59 (P < 0.10). However, TAG supplementation reduced bacterial abundance at %G + C 47-51 (P < 0.05) and increased caecal branched chain fatty acids on clean litter only (P = 0.025). Greater levels of propionic acid were observed for C birds placed on reused litter only (P = 0.008). Litter pH was greater for reused litter pens than clean litter pens at day 21 (P < 0.001). In addition, litter moisture content was less for TAG birds and reused litter pens compared to C birds (P = 0.041) and clean litter pens (P < 0.001), respectively. CONCLUSIONS: These data support the view that irrespective of performance benefits arising from bird placement on reused litter, TAG supplementation to IP-formulated baseline rations impaired growth, supported by the lowered abundance of caecal bacteria known to dominate in well-performing birds and greater levels of caecal branched chain fatty acids.

Bacterial concentration and Campylobacter spp. quantification differ when fresh or ultra-frozen samples are analysed over time using molecular biology and culture-based methods.

The study aimed to delineate the robustness of the culture-based and molecular biology methods to assess the total bacterial concentration and Campylobacter jejuni (C. jejuni) quantification in caecal content, analysed as fresh or after being stored immediately at ultra-low (-80°C) temperature at different time points (for 3, 7, 14, 28 and 62 days post collection). The caecal content was collected from birds that were artificially colonised with C. jejuni (in-vivo), and quantification was performed using both colony-forming unit (CFU) and qPCR. The results showed that storage time affected the output of culture-based analyses but mostly did not alter concentration retrieved via qPCR. After an initial ~4.5 log10 reduction in CFU observed from fresh (day 0) to frozen samples, bacterial concentration retrieved with culture-based methods seemed to be constant in samples frozen for 3 to 62 days, indicating a possible threshold for C. jejuni loss of viability due to effect of storage temperature. Ranking order analyses, revealed that the molecular biology technique was able to attribute somewhat the same relative C. jejuni concentrations to the samples analysed via qPCR. However, day 0 measurements from culture-based methods were associated with the absence of or negatively weak correlations with the rest of the time points, but ranking order was maintained from day 3 onwards. On the other hand, ranking order correlations were less constant when measuring total bacterial concentration through qPCR. The study suggests that if biological samples can't be analysed as fresh (immediately after collection) and have to be stored prior to analysis, then storage at -80°C samples be recommended to avoid the temporal-dependent effects on C. jejuni concentrations. In addition, irrespective of the method of analysis, an initial loss of CFU must be factored in when interpreting the results obtained from frozen samples.

The similarity of the effect of carbohydrase or prebiotic supplementation in broilers aged 21 days, fed mixed cereal diets and challenged with coccidiosis infection.

The aim of this study was to investigate the effect on growth performance and nutrient utilisation when supplementing diets deficient in energy and protein with carbohydrase enzymes or xylo-oligosaccharide in broilers challenged with coccidia. 960 Ross 308 broilers were used in this 21-day study. The treatments were arranged into a 2×4 factorial with 2 challenge states (challenged and non-challenged) and 4 different additive types (control, xylanase alone, xylanase and ß-glucanase mixture and xylo-oligosaccharide). On day 14, the challenged group received 12× the recommended dose of coccidiosis vaccine while the non-challenged group received a sham treatment of water only. The birds and feed were weighed on days 0, 14 and 21. On day 21, two birds per pen were euthanized, the caeca were removed and the contents collected for short chain fatty acid analysis. Six more birds per pen were euthanized and ileal digesta were collected and pooled per pen for nutrient digestibility analysis. Feed intake was greater (P < 0.05) on days 14 and 21 when xylo-oligosaccharide was included in the diet compared to the xylanase and ß-glucanase mixture in birds challenged with coccidiosis. Including xylo-oligosaccharide in the diet improved (P < 0.05) the digestibility of nitrogen and supplementing diets with the xylanase and ß-glucanase mixture improved (P < 0.05) the digestibility of several amino acids. The concentration of arabinose and xylose was (P < 0.001) greater when broiler diets were supplemented with carbohydrase enzymes or xylo-oligosaccharide compared to the control. Although there was an increase in short chain fatty acid production due to the addition of carbohydrase enzymes or xylo-oligosaccharide, there was no additive effect on the %G+C profile of caecal bacteria however there was a negative effect of coccidiosis. In conclusion, the similarity in the response to carbohydrase enzymes or xylo-oligosaccharide supplementation illustrates that the hydrolysis products from carbohydrase activity may have prebiotic like effects.

The effect of carbohydrases or prebiotic oligosaccharides on growth performance, nutrient utilisation and development of small intestine and immune organs in broilers fed nutrient-adequate diets based on either wheat or barley.

BACKGROUND: Non-starch polysaccharides are large complex molecules and are found in cereal grains. This study was conducted to investigate the effect of carbohydrase enzymes or prebiotic oligosaccharides on growth performance, nutrient utilisation and weight of organs associated with the immune system in broilers fed wheat- or barley-based diets. RESULTS: In wheat-based diets, feed intake was lower (P < 0.05) following xylo-oligosaccharide supplementation, whereas in barley-based diets feed intake was greater (P < 0.05) following ß-glucanase supplementation. Gross energy digestibility was improved (P < 0.01) when either level of xylanase was added to wheat diets. Ileal digestible energy was greater (P < 0.01) in wheat diets including an additive compared with the control diet. In wheat diets, bursa weight was lower (P < 0.05) following xylo-oligosaccharide supplementation compared with the control treatment. CONCLUSIONS: The current study showed that supplemented carbohydrases or prebiotic oligosaccharides could alter the development of immune organs or small intestine without any significant effect on growth performance in broilers receiving nutrient-adequate diets. © 2018 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effect of different levels of tryptophan on productive performance, egg quality, blood biochemistry, and caecal microbiota of hens housed in enriched colony cages under commercial stocking density.

A study was conducted to determine the tryptophan (Trp) requirement of brown hens housed in enriched colony cages. A corn and wheat-based diets with 8 levels of standardized ileal digestible (SID) Trp (0.10, 0.13, 0.16, 0.19, 0.22, 0.25, 0.28, and 0.31% of the diet) were manufactured. The diet containing SID Trp 0.10% had no supplemental Trp and was treated as control. A total of 1,344 hens were randomly allocated to 8 treatments, each having 8 replicate cages with 21 hens per cage. Body weight gain (BWG), egg production (EP), feed conversion ratio (FCR), egg quality, blood biochemistry, caecal microbial profile, and concentration of indoles were determined over a period of 16 wk. The EP was linearly improved by supplementing diet with Trp and was highest in 0.25% SID-Trp group compared to control. Trp supplementation improved (P < 0.05) FCR, overall BWG, egg shell characteristics compared to control. The microbial shift in the caecum in response to Trp supplementation was significant in response to higher than current recommendations (0.22% of SID Trp) and indicated a microbial shift towards beneficial bacteria. Indole and skatole concentrations were only significantly different (P < 0.05) when hens in control group were compared with those containing highest levels of SID-Trp. This study demonstrates that when hens are at its peak production and are reared in enriched colony cages their Trp requirement is higher than current National Research Council (1994) recommendations and 0.22% of the SID-Trp in diet can be considered as an optimal level based on regression analysis.

Effect of sodium butyrate on performance, immune status, microarchitecture of small intestinal mucosa and lymphoid organs in broiler chickens.

OBJECTIVE: This study aimed to examine the effect of sodium butyrate (SB) on growth performance, immune status, organs weights, and microarchitecture of lymphoid organs and small intestine. METHODS: A total of 120, 1-d-old broiler chicks were distributed into the following four treatment groups: corn-soy based basal diet (BD) without supplement (control), or the same BD supplemented with 0.1 g/kg zinc bacitracin (ZnB), 0.5 g/kg SB (SB-0.5), or 1.0 g/kg SB (SB-1), respectively. Six birds/group were killed on d-21 and d-35, and samples were collected. RESULTS: Cell-mediated immune response at 48 h post-Phytohemagglutinin-P injection, and antibody titer against Newcastle disease vaccine and sheep red blood cells on d-35 was noted higher (p<0.05) in SB-1 compared to ZnB and control. Lower (p<0.05) feed conversion ratio (FCR) was attained by the supplemented groups. Thymus and spleen weighed more (p<0.05) in SB-1, and bursa registered more (p<0.05) weight in both SB groups compared to control. On d-21, areas of thymus medulla and spleen germinal centers were noted higher (p<0.05) in SB-1 group. The villus height and villus surface area increased (p<0.05) in duodenum and jejunum in both SB groups on d-21, and in SB-1 on d-35, respectively compared to ZnB and control. On d-21, number of goblet cells containing mucins of acidic nature increased (p<0.05) in all the segments of small intestines in SB-1 group compared to control, and on d-35 in ileum compared to other groups. CONCLUSION: In conclusion, SB improved growth performance and immunity as well as modulated morphology of lymphoid organs and gut mucosa in broiler chickens.