Significance of successive feeding of sources of n-3 fatty acids to broiler breeders and their progeny on growth performance, intestinal lesion scores, lymphoid organs weight and plasma immunoglobulin A in broiler chickens challenged with Eimeria

The study examined the effects of successive feeding of sources of n-3 PUFA to broiler breeders (BB) and their progeny in broiler chickens challenged with Eimeria. The BB were fed: 1) control (CON), corn-soybean meal diet, 2) CON + 1 % microalgae (DMA), as a source of DHA and 3) CON + 2.50% co-extruded full fat flaxseed (FFF), as a source of ALA. Eggs were hatched at 34, 44, and 54 wk of age. Posthatch treatments (BB-progeny) were: CON-CON, DMA-CON, FFF-CON, DMA-DMA and FFF-FFF with diets formulated for starter (d 1-10) and grower/finisher (d 11-42) phases. All chicks were orally challenged with Eimeria (E. acervulina and E. maxima) on d 10. Relative to CON, DMA and FFF increased concentration of n-3 PUFA by ≥ 2-fold in hatching eggs and progeny diets. There were no (P > 0.05) interactions between treatment and BB age on d 0 to 10 growth. In general, BB age affected (P < 0.05) growth performance throughout the study. In the starter phase, successive exposure to DHA and ALA improved FCR over CON-CON (P < 0.01). The interaction between treatment and BB age in grower/finisher was such that DHA exposure to younger BB resulted in poor growth performance (P < 0.05) relative to exposure to older BB. In contrast, exposure to ALA had similar (P > 0.05) growth performance irrespective of BB age. Moreover, successive exposure to ALA resulted in higher BWG, breast weight and lower FCR compared to successive exposure to DHA (P < 0.05). There were no (P > 0.05) interactions between treatment and BB age on the intestinal lesion scores, lymphoid organ weights and concentration of plasma immunoglobulin A (IgA). Successive exposure to DHA resulted in higher (P = 0.006) jejunal lesion scores than CON-CON birds. The results showed that successive exposure of DHA and ALA improved FCR relative to non-exposed birds in the starter phase. However, responses in the grower/finisher phase depended on n-3 PUFA type, with birds on successive ALA exposure supporting better growth and breast yield than birds on successive DHA exposure.

The urban political ecology of antimicrobial resistance: A critical lens on integrative governance

The objective of this paper is to integrate Urban Political Ecology (UPE) as a theory for identifying under-exposed urban dimensions of Antimicrobial Resistance (AMR). A UPE lens allows us to conceptualize urbanization as a ubiquitous socio-ecological process and an interpretive frame that could inform AMR governance strategies across related contexts by: a) situating AMR risks in relation to urbanization processes shaping social and political co-determinants of such systemic threats as climate change; b) aligning UPE scholarship with One Health (OH) approaches that address AMR to reveal the under-exposed link of AMR to environmental threats and broader structural dimensions that influence these threats; and c) identifying shared AMR and environmental governance pathways that inform the rationale for more equitable governance arrangements. We delineate a context in which the speed and scale of human activity in the larger context of urbanization, driven by global market integration strategies, impacts human-animal-environmental health threats such as AMR. We demonstrate how UPE scholarship can be leveraged to offer theoretical depth to approaches considering the interdependencies of AMR and climate change threats. We then propose a strategic approach focused on identifying shared governance pathways and intersectoral accountability frameworks to address upstream structural drivers of AM-Environmental threats. The co-benefits of a UPE-informed framework to human-animal-environmental health that leverages enabling policy environments to foster a more collaborative, equitable and sustainable approach to address systemic global health threats are clarified. Just as the concept of "health in all policies" emphasized taking health implications into account in all public policy development, the integration of UPE in AMR governance arrangements would emphasize the need to take other sectors into account through an intersectoral whole-of-government approach that fosters shared AMR - climate change governance pathways.

Systematic review on microbiome-related nutritional interventions interfering with the colonization of foodborne pathogens in broiler gut to prevent contamination of poultry meat

This systematic review aimed to compile the available body of knowledge about microbiome-related nutritional interventions contributing to improve the chicken health and having an impact on the reduction of colonization by foodborne pathogens in the gut. Original research articles published between 2012 and 2022 were systematically searched in Scopus and PubMed. A total of 1,948 articles were retrieved and 140 fulfilled the inclusion criteria. Overall, 73 papers described 99 interventions against colonization by Escherichia coli and related organisms; 10 papers described 15 interventions against Campylobacter spp.; 36 papers described 54 interventions against Salmonella; 40 papers described 54 interventions against Clostridium perfringens. A total of 197 microbiome-related interventions were identified as effective against one or more of the listed pathogens and included probiotics (n = 80), prebiotics (n = 23), phytobiotics (n = 25), synbiotics (n = 12), organic acids (n = 12), enzymes (n = 4), essential oils (n = 14) and combination of these (n = 27). The identified interventions were mostly administered in the feed (173/197) or through oral gavage (11/197), in the drinking water (7/197), in ovo (2/197), intra amniotic (2/197), in fresh or reused litter (1/197) or both in the feed and water (1/197). The interventions enhanced the beneficial microbial communities in the broiler gut as Lactic acid bacteria, mostly Lactobacillus spp., or modulated multiple microbial populations. The mechanisms promoting the fighting against colonization by foodborne pathogens included competitive exclusion, production of short chain fatty acids, decrease of gut pH, restoration of the microbiome after dysbiosis events, promotion of a more stable microbial ecology, expression of genes improving the integrity of intestinal mucosa, enhancing of mucin production and improvement of host immune response. All the studies extracted from the literature described in vivo trials but performed on a limited number of animals under experimental settings. Moreover, they detailed the effect of the intervention on the chicken gut without details on further impact on poultry meat safety.

Growth performance, organs weight, intestinal histomorphology, and oocyst shedding in broiler chickens offered novel single strain Bacillus subtilis isolated from camel dung and challenged with Eimeria

We evaluated a single strain Bacillus subtilis BS-9 direct-fed microbial (BSDFM) isolated from camel dung in Eimeria challenged broiler chickens. Seven-hundred d-old Ross 708 male chicks were placed in pens (25 birds/pen) and allocated to 2 treatments (n = 14). From d 0 to 13, control pens received untreated water (-BSDFM), and 2 treated pens received water and 2 mL x 108 colony forming unit/bird/d (+BSDFM); daily water intake (WI) was recorded. On d 9, birds in half (+Eimeria) of pens per treatment received of 1 mL of Eimeria maxima and Eimeria acervulina oocysts orally, and the other half (-Eimeria) sterile saline solution. Birds had ad libitum access to feed and a water line from d 14. Feed intake (FI), body weight (BW) and mortality were recorded for calculating BW gain (BWG) and feed conversion ratio (FCR). On d 14 and 35, samples of birds were necropsied for organ weight and intestinal measurements. Excreta samples were collected from d 14 to 19 for oocyst count. There was no treatment effect (P > 0.05) on growth performance or WI on d 0 to 9. There were interactions between BSDFM and Eimeria on d 19 (P = 0.014) and 29 (P = 0.036) BW with unchallenged +BSDFM birds being heavier than birds in the other treatments. The main effects (P < 0.05) on d 10 to 35 FI, BW, and BWG were such that +BSDFM increased and Eimeria decreased (P < 0.01) these parameters. There was interaction (P = 0.022) between BSDFM and Eimeria on d 10 to 35 FCR such that the FCR of challenged -BSDFM birds was poor than that of unchallenged counterparts, but none differed with +BSDFM birds. There was an interaction (P = 0.039) between BSDFM and Eimeria on d 14 bursa weight with challenged birds exhibiting heavier bursa than unchallenged +BSDFM birds. Eimeria reduced (P = 0.01) and BSDFM (P = 0.002) increased the villi height to crypt depth ratio. Results showed that BSDFM supplementation via water can support the growth performance of broiler chickens challenged with Eimeria and may be a strategy to reduce adverse effects of coccidiosis.

Comparative impact of bacitracin and select feed additives in the feeding program of Lohmann LSL-Lite pullets at the onset of lay through to 31 weeks of age

There are limited investigations on the role of feed additives in easing transition of pullets to egg production phase. We investigated the effects of supplementation of bacitracin methylene disalicylate (BMD) and select feed additives (myristic acid [MA], benzoic acid [BA], and Aspergillus niger probiotic [PRO]) in feeding program for pullets from the onset of lay through to 31 weeks of age (woa). Parameters measured included hen-day egg production (HDEP), feed intake (FI), feed conversion ratio (FCR), egg quality characteristics, ceca microbial activity, apparent retention of components, and plasma metabolites. A total of 1,200 Lohmann LSL Lite pullets were procured at 18 woa and placed in enriched cages (30 birds/cage) based on body weight (BW) and allocated to five diets. The diets were a basal diet formulated to meet specifications or basal mixed with either BMD, MA, BA, or PRO. Birds had free access to feed and water throughout the experiment. Between 18 and 20 woa, birds fed BMD ate a similar (P > 0.05) amount of feed to BA birds, but more (P = 0.0003) than birds fed basal, MA, or PRO diets. Basal birds had lower HDEP (P = 0.001) and lighter eggs (P < 0.0001) than birds fed any of the feed additives between 21 and 31 woa. The basal hens had a higher (P = 0.009) abundance of Escherichia coli than birds fed BMD, BA, and PRO diets. Consequently, BMD, BA, and PRO birds had a higher (P = 0.011) Lactobacilli: E. coli ratio (LER) than hens fed the basal diet. Specifically, relative to basal-fed hens, the LER of the BMD, MA, BA, and PRO hens was higher by 37%, 21%, 26%, and 45%, respectively. Moreover, birds fed PRO tended to have a higher concentration of ceca digesta acetic acid (P = 0.072) and a lower concentration of isobutyric acid (P = 0.096). In conclusion, supplementing pullet diets with broad-spectrum antibiotics or feed additives (MA, BA, and PRO) had a positive impact on FI, and egg production linked to modulation of indices of gut health. The results suggested supplementing feed additives in feeding programs for pullets at the onset of lay can bolster productivity outcomes.

Diet medication and beta-glucanase affect ileal digesta soluble beta-glucan molecular weight, carbohydrate fermentation, and performance of coccidiosis vaccinated broiler chickens given wheat-based diets

Exogenous enzymes as alternatives to feed antibiotics in poultry has become an emerging research area with the emergence of antibiotic resistance. The objective was to evaluate the effects of diet medication (antibiotics) and β-glucanase (BGase) on digesta soluble β-glucan depolymerization, carbohydrate fermentation, and performance of coccidiosis-vaccinated broiler chickens fed wheat-based diets. A total of 1,782 broilers were raised on litter floor pens, and each treatment was assigned to 1 pen in each of the 9 rooms. The 3 dietary treatments were based on wheat as the sole grain (control, control + medication and control + 0.1% BGase), and the birds were fed the respective treatments ad libitum from 0 to 33 d. Treatments were arranged in a randomized complete block design and analyzed as a one-way ANOVA. Beta-glucanase reduced the peak molecular weight, weight average molecular weight (Mw) and maximum molecular weight for the smallest 10% β-glucan molecules (MW-10%) in ileal digesta at d 11 and 33, whereas diet medication reduced Mw and MW-10% at d 33 compared to the control (P < 0.01). Beta-glucanase and medication reduced the ileal viscosity at d 11 compared to the control (P = 0.010). Ileal propionic acid concentration at d 11 and caecal total SCFA, acetic, and butyric acid concentrations at d 33 were lower in the BGase-supplemented diet than in the control (P < 0.05). The BGase-added diet had higher duodenal pH compared to the control at d 33 (P = 0.026). The effect of medication on carbohydrate fermentation was minimal. Diet medication increased weight gain after d 11, whereas BGase increased the gain for the total trial period compared to the control (P < 0.001). Feed intake was not affected by the dietary treatment. Medication and BGase improved feed efficiency after d 11 compared to the control (P < 0.001). The response to diet medication was larger than BGase, considering weight gain and feed efficiency after d 11 (P < 0.001). In conclusion, diet medication and BGase depolymerized high molecular weight ileal soluble β-glucan and increased overall bird performance. Dietary BGase may benefit bird health in broilers fed wheat-based diets without medication.

Oral administration of chicken NK-lysin or recombinant chicken IL-7 improves vaccine efficacy of Eimeria tenella elongation factor-1α (EF-1α) against coccidiosis in commercial broiler chickens

The synergistic effects of orally-delivered chicken NK-lysin peptide 2 (cNK-2) or recombinant chicken IL-7 (rchIL-7) on vaccination with recombinant Eimeria elongation factor-1α (rEF-1α) against Eimeria maxima (E. maxima) infection was investigated in broiler chickens. Chickens were divided into six groups: control (CON, no Eimeria infection), non-immunized control (NC, PBS), Vaccination 1 (VAC 1, rEF-1α plus cNK-2), Vaccination 2 (VAC 2, rchIL-7 plus cNK-2), Vaccination 3 (VAC 3, rEF-1α/rchIL-7 plus cNK-2), and Vaccination 4 (VAC 4, rEF-1α/rchIL-7 plus cNK-2). All groups, except the CON and NC, were orally treated with cNK-2 for 5 days. The first immunization, except for the VAC 4 group, was performed intramuscularly on day 4, and the second immunization was given with the same concentration of components as the primary immunization one week later. The immunization of the VAC 4 group was carried out by an oral inoculation on the same days. On day 19, all chickens except the CON group, were orally challenged with E. maxima (1.0 × 10⁴ oocysts/chicken). The in vivo vaccination results showed that the VAC 1 and VAC 3 groups produced high (p < 0.05) levels of serum antibody titers to rEF-1α, and the VAC 3 showed enhanced (p < 0.05) levels of serum IL-7. Furthermore, the VAC 3 group showed significantly (p < 0.01) greater body weight gains at 6- and 9-days post-E. maxima infection (dpi) with reduced oocyst shedding at 6 dpi. The average jejunal lesion score of the NC group was 2.5 whereas the VAC 1 group showed a significantly (p < 0.05) lower lesion scores at 6 dpi. E. maxima infection significantly (P < 0.05) up-regulated the expression levels of cytokines (IL-6, IL-10 and IFN-γ) in the jejunum at 4 dpi, but those expressions were down-regulated in VAC 1 or VAC 3 groups. Moreover, the gene expression levels of Jam 2 and Occludin, were significantly (P < 0.05) decreased following E. maxima infection in jejunum at 4 dpi (NC), but their expressions were increased in the VAC 3 group. Collectively, these results showed that the efficacy of rEF-1α vaccination was significantly enhanced when rEF-1α vaccine co-immunized with chIL-7 or cNK-2.

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.

Antibiotics in avian care and husbandry-status and alternative antimicrobials

Undoubtedly, the discovery of antibiotics was one of the greatest milestones in the treatment of human and animal diseases. Due to their over-use mainly as antibiotic growth promoters (AGP) in livestock farming, antimicrobial resistance has been reported with increasing intensity, especially in the last decades. In order to reduce the scale of this phenomenon, initially in the Scandinavian countries and then throughout the entire European Union, a total ban on the use of AGP was introduced, moreover, a significant limitation in the use of these feed additives is now observed almost all over the world. The withdrawal of AGP from widespread use has prompted investigators to search for alternative strategies to maintain and stabilize the composition of the gut microbiota. These strategies include substances that are used in an attempt to stimulate the growth and activity of symbiotic bacteria living in the digestive tract of animals, as well as living microorganisms capable of colonizing the host’s gastrointestinal tract, which can positively affect the composition of the intestinal microbiota by exerting a number of pro-health effects, i.e., prebiotics and probiotics, respectively. In this review we also focused on plants/herbs derived products that are collectively known as phytobiotic.

Effect of methionine and trace minerals (zinc, copper and manganese) supplementation on growth performance of broilers subjected to Eimeria challenge

Coccidiosis is a major intestinal challenge that causes economic loss to the broiler industry. Two battery cage studies were conducted to evaluate the effect of trace minerals, source and dose of methionine on growth performance and gut health of broilers subjected to Eimeria challenge. Experiment #1 consisted of 9 treatments of 2 × 2 × 2 factorial design + 1 arrangement with main factors of methionine (Met) sources (DL-Met vs. 2-hydroxy-4-(methylthio)-butanoic acid (HMTBa)), total sulfur amino acid (TSAA) levels (high vs. low; ±5% of recommended level), and sources of trace minerals (TM) Zn:Cu:Mn in the form Inorganic trace minerals (ITM) in sulfates (80:20:100ppm) vs. mineral methionine hydroxy-analogue bis-chelate (MMHAC, 40:10:50ppm), each with 8 pens of 10 birds. Experiment #2 consisted of 2 treatments--ITM [ZnSO4:tribasic copper chloride (TBCC):MnSO4 110:125:120ppm] and MMHAC (Zn:Cu:Mn, 40:30:40ppm), each with 36 pens of 10 birds. All birds except for treatment 9 in experiment #1 were orally gavaged with 1x, 4x and 16x recommended dose of coccidiosis vaccine on d0, d7 and d14, respectively. Data were subjected to one-way and/or three-way ANOVA, and means were separated by Fisher's protected LSD test with significance at p ≤ 0.05. In experiment #1, factorial analysis revealed the main effects of TSAA level and TM, but not Met source. High TSAA level improved body weight and cumulative feed intake at 14, 20, and 27d. MMHAC improved body weight at 14, and 27d; feed intake at 14, 20, and 27d; and cumulative FCR at 27d vs. sulfates. One-way ANOVA analysis showed that birds fed MMHAC and high levels of TSAA regardless of Met source had similar body weight as unchallenged birds on d27. In experiment #2, MMHAC improved body weight and cumulative FCR, and reduced jejunal IL-17A gene expression on d28. In summary, in broilers subjected to Eimeria challenge, supplementation of the reduced levels of bis-chelated trace minerals MMHAC improved growth performance compared to high levels of ITM (sulfates or TBCC), which might partially result from better immune response, high levels of TSAA improved growth performance, Met source had no effect. Supplementation of both bis-chelated trace minerals MMHAC and high levels of TSAA could overcome the growth performance challenge issue due to coccidiosis.

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.

Knowledge, Attitudes, and Practices of Community Pharmacy Professionals on Poultry Antibiotic Dispensing, Use, and Bacterial Antimicrobial Resistance in Zambia: Implications on Antibiotic Stewardship and WHO AWaRe Classification of Antibiotics

Globally, the inappropriate dispensing and use of antibiotics in animals has contributed to the development of bacterial antimicrobial resistance (AMR). In Zambia, there is insufficient information among community pharmacy professionals on antibiotic use (ABU) and AMR in food-producing animals. This study assessed community pharmacy professionals’ knowledge, attitudes, and practices regarding poultry antibiotic dispensing, use, and bacterial AMR in the Lusaka district of Zambia. A cross-sectional study was conducted among 178 community pharmacy professionals between February and April 2022 using a semi-structured questionnaire. Data were analyzed using Stata version 17. Of the total participants (n = 178), 51.1% (n = 91) were pharmacists. The most dispensed antibiotic was oxytetracycline, a Watch antibiotic, mainly without prescriptions. Good knowledge of ABU and AMR was associated with work experience for more than one year (p = 0.016), while good practices were associated with male gender (p = 0.039) and work experience of more than one year (p = 0.011). The study found moderate knowledge, positive attitudes, and moderate practices of pharmacy professionals on poultry ABU and AMR. There was high dispensing of poultry antibiotics without prescriptions, which calls for strict implementation of antimicrobial stewardship and surveillance programs in poultry production in Zambia to reduce AMR.

Antibiotic Resistance of Bacterial Isolates from Smallholder Poultry Droppings in the Guinea Savanna Zone of Nigeria

There is a growing risk of antibiotic resistance (AR) in smallholder poultry (SP). This study, therefore, aimed to investigate AR pattern of bacterial isolates from SP in the Guinea Savanna agro-ecological zone of Nigeria. A total of 120 fresh poultry droppings were aseptically collected, randomly, from two tropically adapted (FUNAAB Alpha and Noiler) and local chickens. The chickens were raised either using ethnoveterinary medicines (n = 60) or antibiotics (n = 60). Bacterial isolates were characterized and analyzed using standard protocols, and appropriate statistical tools. Compared to Pseudomonas spp. (2.5%) and Klebsiella spp. (5.8%), Salmonella spp. (57.5%) and Escherichia coli (34.2%) were the most prevalent (χ2 = 96.67; p < 0.001). Prevalence of bacterial species was significantly (p = 0.024; Odds Ratio = 2.552) influenced by antibiotics usage. All four species were multi-drug resistant. In total, 30% of the isolates had a multiple AR index ≥ 0.2. Bacterial isolates from FUNAAB Alpha (58.0%) and Noiler (44.0%) were highly resistant to quinolones, while isolates from the local chickens (22.6%) were most resistant to aminoglycosides. Bacterial species isolated from FUNAAB Alpha and local chickens exhibited the lowest and highest percentage of AR, respectively. Clustering of isolates with similar antibiogram revealed inter-species dependence with possibility for inter-species gene transfer. These findings provide a background to investigate the metagenomics of local and improved chickens for AR.

Effects of early feeding of enzymatically treated yeast on growth performance, organ weights, intestinal histomorphology and ceca microbial metabolites in broiler chickens subjected to Eimeria challenge

The study evaluated effects of early feeding of enzymatically treated yeast on growth performance and selected physiological responses in broiler chickens. A total of 480-day-old (male) Ross × Ross 708 broiler chicks were placed in 24 floor pens (20 birds per pen) and allocated to 2 diets (control vs. yeast) in a completely randomized block design (n = 12). Diets were formulated for a 5-phase feeding program: Pre-starter; d 0 to 6 Starter; d 7 to 15, Grower: d 16 to 28, Finisher 1; d 28 to 42 and Finisher 2; d 43 to 56. The yeast was applied in pre-starter and starter diets at 0.6 and 0.2%, respectively. Birds received a common diet from d 16 to 56. Feed intake (FI) and body weight (BW) were recorded by phase for calculation of BW gain (BWG) and FCR. On d 10, all birds received an oral dose of 25,000 E. acervullina and 5,000 E. maxima sporulated oocysts in 1 mL of sterile saline. On d 15 post-hatch, one bird per pen was sacrificed for organ weights (gizzard, small intestine, ceca, liver, spleen, liver, and bursa), jejunal tissues for histomorphology and ceca digesta for microbial activity. On d 56, one bird per pen was sacrificed for organs and breast weight. In pre-starter phase, yeast fed birds showed improved (P < 0.05) BWG and FCR than control fed birds. Combining pre-starter and starter phases, the FCR of yeast fed birds showed improved FCR (1.115 vs. 1.135; P < 0.05) than control. The overall BWG (d 0–56) was 3.920 and 3.962 kg/ bird and corresponding values for FCR were, 1.808 and 1.755, for the control and yeast, respectively. Diets had no (P > 0.05) effects on physiological responses evaluated on necropsied birds except that yeast birds had (P < 0.05) lighter bursa than control birds on d 15. The current data indicated that yeast could support growth in early life of broiler chickens, but these effects were not sustained after the transitioning birds to common grower and finisher diets.

Effects of therapeutic levels of dietary antibiotics on the cecal microbiome composition of broiler chickens

Dietary antibiotics, including antibiotic growth promoters (AGPs), have been commonly used to improve health and growth of poultry. The present study investigated the effects of therapeutic doses of dietary antibiotics, including bacitracin methylene disalicylate (BMD), penicillin G potassium (PP) and an ionophore (salinomycin, SA), on the cecal microbiome of chickens. BMD and SA treatments were given as dietary supplements from d 1 to 35 of age. The SAPP (salinomycin+ penicillin G potassium) group was given SA as a dietary supplement from d 1 to 35 of age and PP was added to drinking water from d 19 to 24 of age to simulate common practices for control of necrotic enteritis in broilers. The cecal contents were collected from all treatment groups on d 10, 24, and 35 of age and DNA was extracted for metagenomic analysis of the cecal microbiome. The results revealed that dietary or water supplementation of therapeutic levels of antibiotics and ionophores to chickens significantly altered the cecal microbial homeostasis during different stages of the chicken life. The alpha diversity analysis showed that BMD, SA, and SAPP treatments decreased diversity and evenness of the cecal microbiome of treated chickens on d 10 of age. Species richness was also reduced on d 35 following treatment with BMD. Beta diversity analyses revealed that SAPP and BMD induced significant changes in the relative abundance of Gram-positive and -negative bacteria on d 10, while no significant differences were observed on d 24. On d 35, the non-treated control group had higher relative abundance of unclassified Gram-positive and -negative bacteria compared to SA, SAPP, and BMD treatment groups. Overall, despite their beneficial role in controlling necrotic enteritis outbreaks, the findings of this study highlight the potential negative effects of dietary supplementation of therapeutic levels of antibiotics on the gut microbiome and suggest that adjusting gut bacteria may be required to restore microbial richness and diversity of the gut microbiome following treatment with these antibiotics.

Impact of fiber on growth, plasma, gastrointestinal and excreta attributes in broiler chickens and turkey poults fed corn- or wheat-based diets with or without multienzyme supplement

Effects of fiber on growth performance, gizzard attributes, ileal digesta viscosity, plasma uric acid (PUA) and excreta characteristics were investigated in broiler chickens (experiment 1) and turkey poults (experiment 2) fed corn or wheat-based diets with or without multienzyme supplement (MES). Fibrous diets were created by adding 10% corn distillers dried grains with solubles or wheat middlings in corn or wheat-based diets, respectively. The MES had main activities of xylanase and β-glucanase. A total of 960-d old Ross x Ross 708 male chicks and 720-d old male Hybrid toms were allocated to eight grain, fiber and MES combinations to give 6 replicates per combination. In each experiment, birds had free access to feed and water for 28 days. Excreta samples were collected for 3-d prior to the end and on d 28, body weight and feed intake were recorded, birds bled and subsequently necropsied for gastrointestinal samples. There was an interaction (P ≤ 0.036) between grain, fiber and MES in broilers final body weight (FBW) and BW gain (BWG). In this context, high fiber corn diets reduced FBW and BWG and supplementation of MES improved these parameters. Broilers fed corn had a higher (P < 0.05) FBW (1,462 vs. 1,424 g) and BWG (1,416 vs. 1,378 g) than birds fed wheat diets. Broilers fed corn-based diets without fiber diets had a higher ileal viscosity and excreta moisture compared to birds fed wheat-based and high fiber diets. Broilers fed low fiber wheat diets without MES had higher (P < 0.05) PUA concentration compared to birds fed low fiber corn diets without MES. Poults fed wheat diets had a higher (P < 0.05) FBW (1,441 vs. 1,408 g) and BWG (1,376 vs. 1,343 g) than poults fed corn diet. The MES supplementation in corn-based diets rich in fiber increased (P = 0.03) gizzard weight in poults. In conclusion, there were varied growth and physiological responses in broilers and turkey suggesting the need for refining enzyme application for different poultry species.