In-feed Antibiotics Research Articles

Effects of tannin-containing diets on performance, gut disease control and health in broiler chicks

The emergence of antibiotic-resistant bacteria in the intestinal microbiota of broiler chickens, and the possibility of antibiotic residues in meat and meat products are seen as a threat to animal and human health. The search for alternatives to conventional drugs, including natural compounds, is an interesting approach to prevent the adverse effects of antibiotics. Therefore, the aim of the present study was to evaluate whether the addition of tannin (as a quebracho extract) in the diet of broiler chickens could be used to replace in-feed antimicrobials and coccidiostatic drugs, to exert positive effects on animal health and performance. The use of tannin in the diet of broiler chicks as an additive (at 0.5% for 1–10-day-old birds; and 1.0% for 11–42-day-old broiler chickens) enhanced their bodyweight, weight gain and daily weight gain on Day 42 of life, compared with the untreated control group (P < 0.05). However, these findings were not observed when tannin was added at 0.5%. Moreover, broiler chickens fed with an extract containing tannins showed higher erythrocyte counts, as well as haemoglobin and haematocrit concentrations than did those in the control group, whereas counts of total leukocytes and lymphocytes were lower (P < 0.05). The use of a diet with tannins did not influence meat quality compared with a diet containing zinc bacitracin and salinomycin, which altered some parameters associated with meat colour. Moreover, the diet with tannins reduced (P < 0.05) the number of oocysts of Eimeria sp. (36-day-old broilers) and the total faecal bacterial counts (42-day-old broilers) compared with the control group. Finally, intestinal histopathology showed that the addition of tannins minimised the degree of lesions (Degree 1) compared with the control group (Degree 3). On the basis of these results, we concluded that the use of quebracho extract containing tannins can be a suitable approach to improve the performance of broiler chickens, replacing in-feed antibiotics and coccidiostatic drugs. The use of tannins did not change meat quality; however, it caused positive effects on the immune system, and exerted potent bactericidal and coccidiostatic properties, reinforcing its use as a replacement for conventional drugs.

Evolution of pig intestinal stem cells from birth to weaning

Pig intestinal epithelium undergoes a complete renewal every 2 to 3 days that is driven by intestinal stem cells (ISCs) located at the crypt base in their niche. Intestinal stem cells generate a pool of highly proliferative transit-amplifying cells, which either migrate up the villus and differentiate into enterocytes and secretory cells or migrate towards the base of the crypt where they differentiate into Paneth cells that secrete antimicrobial peptides. The balance between ISCs’ self-renewal and differentiation controls intestinal epithelial homeostasis; therefore, ISCs are essential for ensuring intestinal epithelial integrity. Detailed knowledge of these mechanisms in pig and other domestic species is very limited. Therefore, the aim of this work was to characterize ISC from birth to weaning. We analysed the duodenum, jejunum and colon of six piglets at birth, 6-day-old nursing piglets and 28-day-old weanlings, one week after weaning. We immunolocalized homeobox only protein+ (HOPX) and sex-determining region Y-box 9+ (SOX9) cells that identify quiescent and active ISC, respectively. The volume of ISCs was quantified with stereological methods and was compared to that of mitotic cells expressing proliferating cell nuclear antigen and apoptotic cells identified by the presence of cleaved caspase-3. Furthermore, we compared all these values with crypts and villi measurements and their ratio. Our results indicated that both quiescent and active ISCs are present in pig intestine from birth to weaning and are localized in the crypts of the small and large intestine. However, both markers were also observed along the villi and on the colon luminal epithelium, suggesting that at these stages, pig mucosa is still immature. Weaning induced a dramatic reduction of both HOPX+ and SOX9+ cells, but SOX9+ cells underwent a significantly greater reduction in the small intestine than in the colon. This suggests that the two ISC types are differentially regulated along the intestinal tracts. Overall, the pig ISC complex has many similarities with its murine counterpart, but also has some differences. These include active ISC not showing the typical columnar base morphology as well as the absence of bona fide Paneth cells. This is the first description of ISC dynamics during pig’s early life and provides useful reference data for future studies, aimed at targeting ISC for the development of efficient alternatives to in-feed antibiotics for preserving intestinal integrity.

Comparative efficacy of antibiotic growth promoter and benzoic acid on growth performance, nutrient utilization, and indices of gut health in nursery pigs fed corn–soybean meal diet

Benzoic acid (BA) supplement was evaluated as an alternative to antimicrobial growth promoter (AGP). Ninety-six piglets (21-d-old at weaning) were placed in pens (four piglets pen−1) based on body weight (BW) and allocated (n = 8) to either control corn–soybean meal diet or control + in-feed antibiotic (AGP, 220 mg chlortetracycline hydrochloride and 31.2 mg tiamulin kg−1) or control + 0.5% BA. Feed intake and BW were measured weekly. Fecal scores for incidence of diarrhea and fecal samples for apparent total tract digestibility (ATTD) of components were taken in week 2. One pig per pen was euthanized on day 14 for jejunal histomorphology and digesta for pH and short-chain fatty acids concentration. In weeks 1–6, pigs fed AGP and BA had better (P < 0.01) gain to feed ratio compared with control fed pigs. On day 12, pigs fed AGP and BA showed lower (P = 0.01) fecal score than control fed pigs. Pigs fed BA had (P < 0.05) higher ATTD of crude protein and taller villi compared with the control or AGP fed pigs. Pigs fed AGP showed higher (P = 0.05) lactic acid concentrations than pigs fed BA, however, none differed (P > 0.05) with control pigs. In conclusion, BA supported piglet growth performance to the same extent as AGP.

Effect of Moringa Oleifera Leaf Powder Supplementation on Pectoral Muscle Quality and Morphometric Characteristics of Tibia Bone in Broiler Chickens

ABSTRACT Although in-feed antibiotics work for broiler chicken´s growth, they are a source of public health hazard. Therefore, there is a need for alternates which can act as growth promoter without deleterious effects on the health of meat consumers. Moringa oleifera is one such phytobiotic which is reported to possess antimicrobial and immuno-modulatory properties. This study investigated the effect of Moringa oleifera leaf powder (MOLP) supplementation on meat quality and bone morphometry of broiler. One-day-old chicks (n=100), divided into five groups (four replicates with n=5), were fed a basal diet (control group) or same diet supplemented with 6, 9, 12 or 15 g/kg MOLP. On d-35, two birds per replicate were euthanized to collect samples of breast muscle, blood and tibia bone. The MOLP supplementation significantly increased pH of breast muscle and ash percentage of tibia bone. The diameter of breast muscle fibres and also weight and weight length index of tibia bone significantly increased with 12 and 15 g/kg MOLP. The water holding capacity (WHC) of breast muscle was significantly higher with 9 and 15 g/kg MOLP; whereas robusticity index of tibia bone significantly decreased with 12 and 15 g/kg MOLP inclusion compared to the control group. In conclusion, dietary supplementation of Moringa oleifera leaf powder (12g/kg) increased pH, water holding capacity, and muscle fibre diameter of breast muscle and also weight, ash percentage and density indices of tibia bone in broiler chickens.

Immunity, immunomodulation, and antibiotic alternatives to maximize the genetic potential of poultry for growth and disease response

Multiple challenges confront the increasing demand for wholesome poultry food products, including governmental restrictions on the use of antibiotic growth promoters (AGPs), nutritional requirements to obtain maximum growth potential, understanding crosstalks among the immunity–microbiota–neuroendocrine system in the gut to maximize intestinal efficiency, high-density production conditions, waste management, and the emergence of infectious pathogens, particularly those that emerge in the antibiotic-free animal production environment. Although in-feed antibiotics have dramatically increased the efficiency of commercial poultry production over the last 50 years, we are now faced with an increasing global crisis concerning the heightened use of antibiotics in animal agriculture and the emergence of multidrug-resistant superbugs that threaten disease management in animals and humans. Therefore, much interest has focused on the development of alternative, antibiotic-free methods of commercial poultry production. Initially, alternatives to antibiotics included any strategies that replace AGPs, but now include any feed additives or treatment that will allow antibiotic-free animal production to prevent and/or treat diseases. These newer disease control strategies can be classified broadly into those that are directly cytotoxic against infectious agents or remove pathogenic toxins, including vaccines, hyperimmune antibodies, antimicrobial peptides, and bacteriophages, and those that augment non-specific host immunity and gut health, including phytochemicals, adjuvants, prebiotics, and probiotics. Furthermore, because the gut microbiota influences various physiological aspects of the immune response, brain function, and gut health, most antibiotic alternatives are expected to promote beneficial microbes that will benefit host physiological responses. However, there is a timely need to better understand the role of the microbiota in gut health if we want to use microbes to modulate the host response to enhance growth performance. This review will highlight current knowledge of host immunity in poultry, and various strategies to modulate host immunity, growth performance, and disease responses to guide the development of alternatives to reduce the use of antibiotics, using a few selected alternatives and a description of their efficacy and modes of action.

MCR-1 Confers Cross-Resistance to Bacitracin, a Widely Used In-Feed Antibiotic.

Extensive use of colistin in food animals is deemed a major driving force for the emergence and transmission of mcr-1 However, a non-colistin usage factor(s) contributing to mobile colistin resistance may also exist in animal production systems. Given that polymyxin, a bacterium-derived peptide antibiotic, has been successfully used as a surrogate to study bacterial resistance to antimicrobial peptides (AMPs), acquisition of MCR-1 may confer cross-resistance to the unrelated AMPs implicated in practical applications. To test this, we first constructed Escherichia coli recombinant strains differing only in the presence or absence of functional MCR-1. Among diverse tested AMPs, MCR-1 was observed to confer cross-resistance to bacitracin, an in-feed antibiotic widely used in animal industry. The significantly (2-fold) increased bacitracin MIC was confirmed by using different bacitracin products, broth media, and laboratory host strains for susceptibility tests. Subsequently, an original mcr-1 gene-bearing plasmid, pSLy21, was conjugatively transferred to eight clinical E. coli recipient strains isolated from diarrheic pigs, which also led to significantly increased MICs of both colistin (4-fold to 8-fold) and bacitracin (2-fold). Growth curve examination further demonstrated that MCR-1 provides a growth advantage to various E. coli strains in the presence of bacitracin. Given that bacitracin, a feed additive displaying low absorption in the intestine, can be used in food animals with no withdrawal required, imprudent use of bacitracin in food animals may serve as a risk factor to enhance the ecological fitness of MCR-1-positive E. coli strains, consequently facilitating the persistence and transmission of plasmid-mediated colistin resistance in agricultural ecosystem.IMPORTANCE Polymyxins (e.g., colistin) are the drugs of last resort to treat multidrug-resistant infections in humans. To control mobile colistin resistance, there is a worldwide trend to limit colistin use in animal production. However, simply limiting colistin use in animal production may still not effectively mitigate colistin resistance due to an overlooked non-colistin usage factor(s). Using controlled systems, in this study, we observed that MCR-1 confers cross-resistance to bacitracin, a popular in-feed antibiotic used in food animals. Thus, imprudent and extensive usage of bacitracin in food animals may serve as a non-colistin usage risk factor for the transmissible colistin resistance. Further comprehensive in vitro and in vivo studies are highly warranted to generate science-based information for risk assessment and risk management of colistin resistance, consequently facilitating the development of proactive and effective strategies to mitigate colistin resistance in animal production system and protect public health.

Using ruminally protected and nonprotected active dried yeast as alternatives to antibiotics in finishing beef steers: growth performance, carcass traits, blood metabolites, and fecal Escherichia coli.

The objective of this study was to evaluate the effects of supplementing the diet of finishing beef steers with active dried yeast (ADY) in ruminally protected and nonprotected forms on growth performance, carcass traits, and immune response. Seventy-five individually-fed Angus steers (initial body weight (BW) ± SD, 448 ± 8.4 kg) were assigned to a randomized complete design with 5 treatments: 1) control (no monensin, tylosin, or ADY), 2) antibiotics (ANT, 330 mg monensin + 110 mg tylosin·steer-1d-1), 3) ADY (1.5 g·steer-1d-1), 4) encapsulated ADY (EDY; 3 g·steer-1d-1), and 5) a mixture of ADY and EDY (MDY; 1.5 g ADY + 3 g EDY·steer-1d-1). Active dried yeast with 1.7 × 1010 cfu/g was encapsulated in equal amounts of ADY and capsule materials (stearic acid and palm oil). Steers were fed a total mixed ration containing 10% barley silage and 90% barley-based concentrate mix (dry matter [DM] basis). The ANT, ADY, and EDY were top-dressed daily to the diet at feeding. Intake of DM, final BW, averaged daily gain (ADG), and gain-to-feed ratio (G:F) were unaffected by ADY or EDY. Carcass traits including hot carcass weight (HCW), dressing percentage, marbling score and quality grade did not differ among treatments, although fewer severely abscessed livers were observed (P < 0.05) with ADY and MDY compared with the other treatments. Plasma urea N tended (P < 0.10) to be greater in steers fed ANT, ADY, or EDY on day 56 and 112, while glucose remained stable in all treatments except greater (P < 0.02) plasma glucose occurred in steers fed MDY on day 112. Serum nonestrified fatty acid (NEFA) was unaffected by ADY or EDY, but it was greater (P < 0.03) in steers fed ANT compared with control. Plasma haptoglobin (Hp) and serum amyloid A (SAA) were affected by yeast supplementation on day 112, with greater (P < 0. 01) Hp in steers fed ADY, EDY, or MDY and lesser (P < 0.01) SAA in steers fed EDY and MDY than control. Lipopolysaccharide binding protein concentrations were greater (P < 0.01) in steers fed EDY and MDY on day 56. Supplementing with ADY (protected or nonprotected) or ANT had no effect on fecal IgA contents on day 56 and 112. Steers fed yeast (EDY or MDY) tended (P < 0.10) to have fewer fecal Escherichia coli counts than the control and ANT on day 56 and 112. These results indicate that feeding ADY to feedlot cattle may exhibit antipathogenic activity that conferred health and food safety beneficial effects including reduced liver abscess and potentially pathogen excretion, thus yeast may be an alternative to in-feed antibiotics in natural beef cattle production systems.

The effects of group size and subtherapeutic antibiotic alternatives on growth performance and morbidity of nursery pigs: a model for feed additive evaluation.

The objectives of this experiment were to evaluate the effects of alternatives to antibiotic growth promoters (AGP), two group sizes, and their interaction on nursery pig performance to serve as a model for future AGP alternative studies. A 41-d experiment was conducted in a commercial wean-to-finish barn; 1,300 piglets weaned at 21 d of age (weaned 2 or 4 d prior to experiment; 6.14 ± 0.18 kg BW; PIC 1050 sows and multiple sire lines) were blocked by sire, sex, and weaning date, then assigned to eight treatments: four dietary treatments each evaluated across two group sizes. The four dietary treatments were: negative control (NC), positive control (PC; NC + in-feed antibiotics), zinc oxide plus a dietary acidifier (blend of fumaric, citric, lactic, and phosphoric acid) (ZA; NC + ZnO + acid), and a Bacillus-based direct-fed-microbial (DFM) plus resistant potato starch (RS) (DR; NC + DFM + RS). The two group sizes were 31 or 11 pigs/pen; floor space was modified so area/pig was equal between the group sizes (0.42 m2/pig). There were 7 pens/diet with 11 pigs/pen and 8 pens/diet with 31 pigs/pen. Data were analyzed as a randomized complete block design with pen as the experimental unit. Diagnostic assessment of oral fluids, serum, and tissue samples was used to characterize health status. Pigs experienced natural challenges of acute diarrhea and septicemia in week 1 and porcine reproductive and respiratory syndrome virus (PRRSV) in weeks 4–6. There was a significant interaction between diet and group size for ADG (P = 0.012). PC increased ADG in large and small groups (P < 0.05) and ZA increased ADG only in large groups (P < 0.05). Small groups had improved ADG compared to large groups when fed NC or DR diets (P < 0.05). Similarly, PC increased ADFI (P < 0.05). Compared to NC, ZA improved ADFI in large groups only (P < 0.05; diet × group size: P = 0.015). Pigs fed PC had greater G:F than NC (P < 0.05), and small groups had greater G:F than large groups (P < 0.05). There was no effect of ZA or DR on G:F. Pigs fed PC required fewer individual medical treatments than NC and pigs fed ZA were intermediate (P = 0.024). More pigs were removed from large than small groups (P = 0.049), and there was no effect of diet on removals (P > 0.10). In conclusion, careful study design, protocol implementation, sample collection, and recording of important information allowed us to characterize the health status of this group of pigs and determine treatment effects on growth performance and morbidity.

Effect of alpha-tocopherol acetate and ascorbic acid on performance, carcass traits, and incidence and severity of liver abscesses in feedlot cattle.

Liver abscesses (LA) in cattle negatively affect feedlot performance by decreasing ADG, feed intake, and G:F ratio. Abscessed livers are condemned and abdominal adhesions associated with LA can result in extensive carcass trimming during harvest, further compounding adverse economic impact. Given regulatory changes pertaining to the use of in-feed antibiotics in cattle production, there is growing interest in alternatives to antibiotics for LA control. The objective of this study was to evaluate the use of antioxidants, crystalline ascorbate (AOX), and alpha-tocopherol acetate, for mitigation of LA in feedlot cattle. Yearling crossbred heifers (n = 392; initial BW 481 ± 9.4 kg) were blocked by previous treatment and allocated randomly to 24 dirt-surfaced feedlot pens (10 m × 35 m) with 14 heifers/pen. Heifers were weighed, implanted with Component TE-200 implants, and placed into feeding pens. Finishing diets consisted of 60% steam-flaked corn, 30% wet corn gluten feed, 8% alfalfa, and 2% supplement (DM basis) that provided 300 mg/d monensin, and either 200 IU/d alpha-tocopherol acetate (CTL) or 2,000 IU/d alpha-tocopherol acetate plus 500 mg/d crystalline AOX. Heifers were fed once daily ad libitum for 94 d, then weighed and transported 450 km to a commercial abattoir for harvest. Hot carcass weight and incidence/severity of LA were determined the day of harvest, and carcass traits were evaluated following 36 h of refrigeration. Compared to CTL, feeding AOX tended to decrease DMI (10.66 vs. 10.31 kg/d; P = 0.08) and improve G:F (0.1204 vs. 0.1254; P = 0.12), but did not impact ADG, incidence of LA (25.6 vs. 23.5% for CTL and AOX, respectively), HCW (828.4 vs. 830.5 kg for CTL and AOX, respectively), or other carcass traits (P > 0.20). In conclusion, feeding antioxidants are not a viable alternative to decrease incidence of LA in finishing cattle.

Contribution of exogenous enzymes to potentiate the removal of antibiotic growth promoters in poultry production

Removal of prophylactic in-feed antibiotics from the diets of animals that enter the human food chain is increasing on a global basis. This removal is motivated by a range of factors including legislative compliance, consumer and retailer pressure and for ethical reasons. However, whilst this shift in approach to the rearing of production animals has benefits, there are also significant challenges for animal husbandry, disease control, nutritional optimization and food safety and security. For example, the use of in-feed antibiotics generates increases in weight gain and feed conversion ratio in the region of 4% and so, axiomatically, their removal introduces significant efficiency cost for producers. The vacuum created by the removal of in-feed antibiotics has led to a sustained body of research into alternative additives such as plant secondary metabolites, pro- and pre-biotics, acidifiers and enzymes. Whilst no single alternative to date can claim to demonstrably and consistently replace the antibiotics, many of these additives have substantial value and can form part of successful ‘anti-biotic free’ production programs. It is therefore the purpose of this review article to summarise the consequences of removal of in-feed antibiotics and to highlight the potential of feed enzymes as part of a displacement strategy.

Dietary L-glutamine supplementation improves growth performance, gut morphology, and serum biochemical indices of broiler chickens during necrotic enteritis challenge

Necrotic enteritis (NE) causes significant economic losses in the broiler chicken industry, especially in birds raised without in-feed antibiotics. L-glutamine (Gln) is an amino acid that may compensate for metabolic losses from infection and improve the intestinal development. This study investigated the effects of dietary Gln (10g/kg) supplementation on growth performance, intestinal lesions, jejunum morphology, and serum biochemical indices of broiler chickens during NE challenge. The study employed a factorial arrangement of treatments with factors: NE challenge, no or yes; dietary Gln inclusion, 0g/kg in starter (S), d 0 to 10, grower (G) d 10 to 24, and finisher (F) d 24 to 35; 10g/kg in S, G, F, or 10g/kg in S, G only. Each treatment was replicated in 6 floor pens with 17 birds per pen as the experimental unit for performance and 2 birds for other measurements. Challenge significantly reduced bird performance, increased incidence of intestinal lesions, and affected intestinal development and serum biochemical indices. Regardless of challenge, Gln supplementation increased gain (P < 0.05), feed intake (P < 0.05), and decreased FCR (P < 0.05) on d 24. On d 35, Gln improved gain (P < 0.05) and FCR (P < 0.001) whereas withdrawing Gln from finisher tended to diminish the beneficial effect on weight gain but not FCR. Dietary Gln reduced lesion scores in the jejunum (P < 0.01) and ileum (P < 0.01) in challenged birds. On d 16, Gln increased villus height to crypt depth ratio in unchallenged birds (P < 0.05) and reduced crypt depth of challenged birds on d 24 (P < 0.05). Regardless of challenge, supplementation with Gln reduced crypt depth on d 16 (P < 0.05), and increased villus height (P < 0.01) and the villus height to crypt depth ratio (P < 0.001) on d 24. Dietary Gln lowered serum uric acid level regardless of challenge (P < 0.05). The current study indicates that dietary Gln alleviates adverse effects of NE and may be useful in antibiotic-free diets.

Effects of fatty acid glyceride product SILOhealth 104 on the growth performance and carcass composition of broiler chickens

Butyric acid is the primary energy source for colonocytes, and has shown potential as an alternative to in-feed antibiotics, due to its antimicrobial activity and positive effects on production performance traits of broiler chickens. SILOhealth 104 (SILO S.P.A., Florence, Italy) is a commercial product mainly containing mono- and di-glycerides of butyrate with a small portion of propionic, caprylic, capric, and lauric acid mono- and di-glycerides. Its effects on broiler performance and carcass composition have yet to be evaluated. Four-hundred-eighty day-old male Ross 308 birds were divided into different dietary treatment groups with equal starting weights and fed a diet containing 0, 500, 1,000, 2,000, or 3,000ppm of SILOhealth 104 for 35 days. There were no significant differences in overall average daily gain or feed: gain ratio with the addition of SILOhealth 104 to the diets (P > 0.05). At 5 wk of age, abdominal fat weight was reduced in birds supplemented with SILOhealth 104 in a dose-responsive manner (P < 0.05), while breast muscle weight increased with supplementation, with significant increases in 2,000ppm and 3,000ppm birds compared to controls (P < 0.05). A significant reduction in gene expression of both forkhead box protein O4 and myostatin, 2 factors that can inhibit protein synthesis, was found in the breast muscle of all SILOhealth 104 treated birds (P < 0.05). In addition, gene expression in the adipose tissue, including acetyl-CoA carboxylase alpha and lipoprotein lipase, which are associated with lipid metabolism, was significantly decreased and increased, respectively, by the supplementation of SILOhealth 104 (P < 0.05). These data suggest that the components of SILOhealth 104 can positively affect the deposition of muscle, while reducing abdominal fat deposition in broiler chickens.

Upregulation of genes encoding digestive enzymes and nutrient transporters in the digestive system of broiler chickens by dietary supplementation of fiber and inclusion of coarse particle size corn

BackgroundMeasures to improve bird performance have been sought due to the imminent phase out of in-feed antibiotics in poultry and continued demand for higher poultry feeding efficiency. Increasing grain particle size and dietary fibre may improve gizzard function, digestive efficiency and nutrient absorption. This study was conducted to evaluate the effect increased particle size of corn and inclusion of sugarcane bagasse (SB) on mRNA expression of genes encoding digestive enzymes and nutrient transporters in broilers.ResultsA total of 336 day-old Ross 308 males were assigned in a 2 × 2 factorial arrangement of treatments with corn particle size - coarse 3576 μm or fine 1113 μm geometric mean diameter, and SB - 0 or 2% inclusion. Feed conversion ratio (FCR), weight gain and feed intake were measured from d 0–10 and d 10–24. The relative gizzard weight and mRNA expression of genes encoding digestive enzymes and intestinal nutrient transporters were measured on d 24. During d 10–24, a particle size × SB interaction was observed for FCR (P < 0.01), where birds fed coarsely ground corn (CC) with 2% SB had lower FCR than those fed CC without SB. A particle size × SB interaction was observed for both expression of pepsinogen A and C (P < 0.01) which were negatively correlated with FCR on d 24. Addition of 2% SB upregulated pepsinogen A and C only in CC fed birds. Further, 2% SB also upregulated pancreatic amylase (AMY2A) and intestinal cationic amino acid transporter-1 (CAT1). Inclusion of dietary CC upregulated duodenal amino peptidase N (APN), jejunal alanine, serine, cysteine and threonine transporter-1 (ASCT1), and ileal peptide transporter-2 (PepT2).ConclusionThese results suggest that both SB and coarse particle size modulate expression of genes encoding important digestive enzymes and nutrient transporters and thus are directly related to bird performance. These findings provide insights into the combination effects of dietary fiber and particle size in the future management of broiler feeding.

RETRACTED ARTICLE: Antibiotic growth promoters virginiamycin and bacitracin methylene disalicylate alter the chicken intestinal metabolome

Although dietary antibiotic growth promoters have long been used to increase growth performance in commercial food animal production, the biochemical details associated with these effects remain poorly defined. A metabolomics approach was used to characterize and identify the biochemical compounds present in the intestine of broiler chickens fed a standard, unsupplemented diet or a diet supplemented with the antibiotic growth promoters, virginiamycin or bacitracin methylene disalicylate. Compared with unsupplemented controls, the levels of 218 biochemicals were altered (156 increased, 62 decreased) in chickens given the virginiamycin-supplemented diet, while 119 were altered (96 increased, 23 decreased) with the bacitracin-supplemented diet. When compared between antibiotic-supplemented groups, 79 chemicals were altered (43 increased, 36 decreased) in virginiamycin- vs. bacitracin-supplemented chickens. The changes in the levels of intestinal biochemicals provided a distinctive biochemical signature unique to each antibiotic-supplemented group. These biochemical signatures were characterized by increases in the levels of metabolites of amino acids (e.g. 5-hydroxylysine, 2-aminoadipate, 5-hydroxyindoleaceate, 7-hydroxyindole sulfate), fatty acids (e.g. oleate/vaccenate, eicosapentaenoate, 16-hydroxypalmitate, stearate), nucleosides (e.g. inosine, N6-methyladenosine), and vitamins (e.g. nicotinamide). These results provide the framework for future studies to identify natural chemical compounds to improve poultry growth performance without the use of in-feed antibiotics.

Effect of feeding duration of &lt;i&gt;Spirulina platensis&lt;/i&gt; on growth performance, haematological parameters, intestinal microbial population and carcass traits of broiler chicks

Spirulina platensis is a good candidate as an in-feed antibiotics substitute for broilers. However, its use seems impractical owing to its high price, especially when being administered throughout the whole rearing period. This study aimed to investigate the effects of feeding duration of S. platensis on growth, haematological parameters, intestinal microbial population, and carcass traits of broiler chicks. A total of 288 one-day-old broiler chicks were randomly allotted to one of four groups, including control (basal diet with 0.04% zinc bacitracin) (CONT) and birds receiving basal diet supplemented with 1% of S. platensis for the first seven days (SP-7), for 21 days (SP-21), and for 35 days (SP-35). In this study, treatments had no significant effect on the growth performance of broilers. The caecum relative weight was significantly higher in SP-35 than in CONT and SP-21 birds. The values of haemoglobin, erythrocytes, and haematocrit were significantly lower in SP-35 than in other birds. Compared with CONT, SP-35 birds had significantly lower numbers of leukocytes, lymphocytes, and a lower number of eosinophils. The numbers of coliform were significantly lower in the ileum of SP-21 than in CONT and SP-7 birds. In the caecum, coliform tended to be lower in SP-21 than in other birds. There was no significant difference in the carcass traits of broilers across the groups. In conclusion, the administration of S. platensis for the first 21 days of broilers’ life resulted in similar or even better responses than administration of S. platensis or in-feed antibiotics throughout the rearing period. Keywords: Blood profile, bodyweight, broilers, carcass quality, feeding period, green alga, in-feed antibiotics

Intermittent lighting improves resilience of broilers during the peak phase of sub-clinical necrotic enteritis infection

Necrotic enteritis, either in its clinical or sub-clinical form is known to cause massive economic losses in the broiler chicken industry. Currently, the use of in-feed antibiotics as growth promoters is discouraged. Therefore, mechanisms to control NE through diet include reduction of digesta viscosity, promotion of lower pH in the gastrointestinal tract (GIT) through acidification of feed, production of short-chain fatty acids and overall stimulation of beneficial bacteria growth. Intermittent lighting programs increase feed retention in the crop and reduce pH in the foregut compartments in comparison with standard commercial lighting programs and therefore may be a valuable, yet underexploited, barrier to prevent the invasion of the GIT by pathogens. In this experiment, a 2 × 2 factorial arrangement of treatments was employed in a randomized design to investigate whether intermittent lighting would increase broiler resilience to sub-clinical necrotic enteritis. A total of 390 Cobb 500 same-hatch, mixed sex, day-old chicks were assigned to 30 floor pens to test the effect of 2 factors, namely, lighting schedule (continuous, 18L:6D vs. intermittent, 1L:3D:1L:3D:1L:3D:1L:3D:2L:6D) and a sub-clinical necrotic enteritis challenge (challenge vs. no challenge). Challenged birds had lower feed intake and weight gain and poorer feed conversion ratio (FCR; P < 0.005). Intermittent lighting reduced feed intake (P < 0.05) without compromising final body weight gain. During the peak phase of Clostridium perfringens Type A infection, the negative impact of the disease challenge on feed efficiency was lower for animals under intermittent lighting than for those under a 18L:6D schedule (2-way interaction, P < 0.005). Thus, in flocks that are raised under antibiotic-free production systems, intermittent lighting programs applied at least during the critical period for necrotic enteritis risks, i.e., d 18–24, may be a practical, non-medicated way to increase resilience of broilers to this disease.

Dietary modulation of endogenous host defense peptide synthesis as an alternative approach to in-feed antibiotics.

Traditionally, antibiotics are included in animal feed at subtherapeutic levels for growth promotion and disease prevention. However, recent links between in-feed antibiotics and a rise in antibiotic-resistant pathogens have led to a ban of all antibiotics in livestock production by the European Union in January 2006 and a removal of medically important antibiotics in animal feeds in the United States in January 2017. An urgent need arises for antibiotic alternatives capable of maintaining animal health and productivity without triggering antimicrobial resistance. Host defense peptides (HDP) are a critical component of the animal innate immune system with direct antimicrobial and immunomodulatory activities. While in-feed supplementation of recombinant or synthetic HDP appears to be effective in maintaining animal performance and alleviating clinical symptoms in the context of disease, dietary modulation of the synthesis of endogenous host defense peptides has emerged as a cost-effective, antibiotic-alternative approach to disease control and prevention. Several different classes of small-molecule compounds have been found capable of promoting HDP synthesis. Among the most efficacious compounds are butyrate and vitamin D. Moreover, butyrate and vitamin D synergize with each other in enhancing HDP synthesis. This review will focus on the regulation of HDP synthesis by butyrate and vitamin D in humans, chickens, pigs, and cattle and argue for potential application of HDP-inducing compounds in antibiotic-free livestock production.

Effects of spray-dried porcine plasma on fecal microbiota in nursery pigs.

Spray-dried porcine plasma (SDPP) has been considered as an alternative for in-feed antibiotics to improve pig growth performance; however, the effect of SDPP on gut microbiota is unknown. The objective of this study was to evaluate effects of feeding SDPP on fecal microbial communities of nursery pigs. Ninety-six weaned pigs were assigned to 16 pens, which were allotted to two dietary treatments, including the control or the control + SDPP (5% and 2.5% SDPP inclusion in phase 1 and 2, respectively) diet. Fecal samples were collected at d 0, 7, 14, 21, and 28. Multiplex sequencing of V3 region of the 16S rRNA gene was used to characterize the bacterial community structure of fecal samples. Pearson's correlation tests were performed in Calypso to identify bacterial taxa that were either positively or negatively associated with overall growth performance. Feeding SDPP altered microbial structure at family, genus, and operational taxonomic unit (OTU) classifications; however, fecal microbes shifted with time. At the family level, Clostridiaceae increased (P < 0.001) on d 14, but decreased (P < 0.05) on d 28 in SDPP-fed pigs compared with control pigs. Decreased Veillonellaceae (P < 0.05; d 14) and Lachnospiraceae (P = 0.001; overall) were observed in SDPP-fed pigs compared with control pigs. Feeding SDPP increased lactic acid-producing bacteria (Lactobacillus delbrueckii, d 7) and cellulolytic bacteria (Ruminococcus albus, d 7; Clostridium thermocellum, d 7 and 14; and Clostridium saccharoperbutylacetonicum/beijerinckii, d 14; and Megasphaera elsdenii, d 21). On d 28, feeding SDPP decreased (P < 0.05) Clostridium difficile compared with control pigs. In conclusion, feeding SDPP altered fecal microbial communities in nursery pigs. The results of this study may provide information to help explain the positive effects associated with feeding SDPP on nutrient digestibility and gut health of nursery pigs.

Growth Performance, Gut Microbiota and Haemato-Biochemical Profile of Quails Fed Diet Supplemented with Graded Levels of &amp;lt;i&amp;gt;D. glomerata&amp;lt;/i&amp;gt; Fruit Powder

As a consequence of the antibiotics growth promoters restriction in livestock farming, there is a growing interest in plant feed additives. This study was designed to evaluate the effects of supplementing D. glomerata fruit powder on growth performance of Japanese quails. A total of 200 two weeks-old Japanese quail were randomly allocated to five experimental treatment groups. Experimental diets consisted of incorporating D. glomerata powder in the control ration (T0) at 2g (T1), 4g (T2) and 6g/kg (T3) of feed. Quails fed with D. glomerata supplemented diets were compared to quails fed on diet without any supplement (T0) and an antibiotic (1g/kg) medicated diet (T0+). Throughout the production period feed intake was not significantly affected by the experimental rations. Weight gain was significantly higher (p 0.05) on the relative weight of organs when compared to the control diets. WBC, MCV, MCH, and MCHC were not significantly (p>0.05) affected by this spice. RBC significantly increased (p<0.05) with 6g/kg D. glomerata compared to the negative control diet, while Hgb and PCV decreased (p<0.05) compared to the positive control diet for the same treatment. Serum content in triglycerides was significantly higher (p<0.05) with 6g/kg D. glomerata compared to all other treatments. ASAT, ALAT, creatinine, total protein, albumin, urea, total cholesterol, HDL, LDL were not significantly affected by the inclusion of D. glomerata in the ration. Irrespective of the level of incorporation of D. glomerata, lactic acid bacteria count significantly increased as compared to Escherichia coli, Samonella and Staphylococcus spp. In conclusion, D. glomerata can be used up to 4g/kg as substitutes for infeed antibiotics for gut microbiota modulation and better weight gain without any adverse effects on the haemato-biochemical parameters of quail.

Tannins and Bacitracin Differentially Modulate Gut Microbiota of Broiler Chickens.

Antibiotic growth promoters have been used for decades in poultry farming as a tool to maintain bird health and improve growth performance. Global concern about the recurrent emergence and spreading of antimicrobial resistance is challenging the livestock producers to search for alternatives to feed added antibiotics. The use of phytogenic compounds appears as a feasible option due to their ability to emulate the bioactive properties of antibiotics. However, detailed description about the effects of in-feed antibiotics and alternative natural products on chicken intestinal microbiota is lacking. High-throughput sequencing of 16S rRNA gene was used to study composition of cecal microbiota in broiler chickens supplemented with either bacitracin or a blend of chestnut and quebracho tannins over a 30-day grow-out period. Both tannins and bacitracin had a significant impact on diversity of cecal microbiota. Bacitracin consistently decreased Bifidobacterium while other bacterial groups were affected only at certain times. Tannins-fed chickens showed a drastic decrease in genus Bacteroides while certain members of order Clostridiales mainly belonging to the families Ruminococcaceae and Lachnospiraceae were increased. Different members of these groups have been associated with an improvement of intestinal health and feed efficiency in poultry, suggesting that these bacteria could be associated with productive performance of birds.