Bromelain can reduce the negative effects of a subclinical necrotic enteritis in broiler chickens.

This study was conducted to examine the efficacy of a bromelain-based supplementation coded ANR-pf on growth performance and intestinal lesion of broiler chickens under necrotic enteritis (NE) challenge. A total of 540 Ross 308 day-old male chicks were randomly allocated into 6 treatments of 6 replicates. The bromelain formulation was delivered to chickens through gavaging or in drinking water method twice, on d 8 and 13. Nonchallenged groups included 1) without or 2) with the specific bromelain formulation gavaged at 0.8 mL/kg. NE-challenged groups included 3) without the specific bromelain formulation; 4) gavaged with 0.4 mL/kg; 5) gavaged with 0.8 mL/kg and 6) supplemented with 0.8 mL/kg via drinking water. Birds were challenged with Eimeria spp. on d 9 and Clostridium perfringens (NE-18 strain) on d 14 and 15. On d 14 and 19, fresh faecal contents were collected for the determination of oocyst counts. Intestinal lesion scores were determined on d16. Performance and mortality were recorded throughout the entire experiment. Among challenged groups, birds received additive via drinking water had higher weight gain (WG) compared to the remaining groups (P < 0.001) in the grower phase and had lower FCR compared to 0.4 mL/kg inoculated group in the grower and finisher phases (P < 0.001). Bromelain supplementation via drinking water improved the WG of challenged birds, similar to that of the nonchallenged birds (P < 0.001), and lowered FCR compared to other challenged groups (P < 0.001). Nonchallenged birds and birds that received bromelain formulation in drinking water did not have lesions throughout the small intestine whereas challenged birds, either un-supplemented or supplemented with bromelain via inoculation route recorded similar lesion score levels in the jejunum. At d 19, birds received bromelain in drinking water had lower fecal oocyst numbers compared to challenged birds without additive (P < 0.001). In conclusion, bromelain administration via drinking water could ameliorate the negative impacts of NE-infection in broilers by improving performance, lowering the oocyst numbers and lesion scores.

The effect of sex and dietary crude protein level on nutrient transporter gene expression and cecal microbiota populations in broiler chickens.

It is well known that male and female broilers differ in their growth performance and that many physiological factors contribute to this difference. The aim of this experiment is to investigate if there are differences between male and female broilers in cecal microbiota and nutrient transporter gene expression and if these differences play a role in the growth performance of broilers. The possible effect of protein level and its interaction with sex on microbiota and expression of the nutrient transporters were also investigated. Samples were collected from male and female birds fed either standard crude protein (SCP) or reduced crude protein diets (RCP) at the age of d 35. The experiment was designed as a 2 × 2 factorial arrangement of treatments consisting of 448 Cobb 500 broilers assigned to 32-floor pens with 4 treatments, 8 replicates, and 14 birds per pen for performance measurements. The factors were sex (male or female) and dietary crude protein (CP) level (standard or reduced). Body weight gain (BWG), feed intake and feed conversion ratio were recorded for each pen. Sex had a significant effect on BWG and FCR (P < 0.001) where males had a significantly higher BWG and better FCR compared to females. There was a significant interaction between sex and protein level on feed intake (FI) (P < 0.05), where male birds had a higher FI compared to female birds only when the birds were fed SCP but not RCP diets. There was a significant interaction between CP level and sex on the expression of CAT2 (P = 0.02) and PEPT2 (P = 0.026) where the genes were significantly upregulated in females but only when the RCP diet was fed. The RCP diet upregulated the expression of BoAT (P = 0.03) as a main effect. Female birds had significantly higher expression of the PepT-2 gene compared to the males. The alpha diversity of the cecal microbiota showed differences among the treatments. The Shannon diversity index was statistically higher (P = 0.036) for males fed the SCP diet and the Chao1 index for evenness was statistically higher (P = 0.027) in females fed the SCP diet. There was also a difference in the relative abundance of the 15 most common genera found in the cecal content of the broilers in this experiment and lastly, the differential composition of microbiota between the different treatments was also significantly different. This study suggests that chickens are able to compensate for a reduction in AA substrates when fed a low CP diet through the upregulation of certain AA transporters, females may adapt to low CP diets better by such upregulation compared to males, and lastly, sex has an effect on the cecal microbial population and these differences contribute towards the performance differences between male and female broilers.

Sources and levels of copper affect liver copper profile, intestinal morphology and cecal microbiota population of broiler chickens fed wheat-soybean meal diets.

Super dosing copper (Cu) has long been used as an alternative to antibiotic growth-promoters in broiler chickens' diet to improve gut health. This study was designed to compare nutritional and growth-promoting levels of Cu hydroxychloride (CH) with CuSO4 on gut health bio-markers and liver mineral profile of broiler chickens. Ross 308 chicks (n = 864) were randomly assigned to eight treatments, as basal diet containing no supplemental Cu; the basal diet with 15 or 200 mg/kg Cu as CuSO4; or 15, 50, 100, 150 or 200 mg/kg Cu from CH. The highest liver Cu content was observed in birds fed the diets with 200 mg/kg CuSO4 (P < 0.01). Serum FITC-d concentration as the leaky gut marker, and liver malondialdehyde concentration were not affected. Copper level or source had no effect on cecal short chain fatty acid and the mRNA expression of five jejunal genes involved in gut integrity. Negative linear responses of Cu were observed on Lactobacillus (P = 0.032), Bacteroides (P = 0.033), and Enterobacteriaceae (P = 0.028) counts. The jejunal villus height increased in birds fed CH at 200 and 100 mg/kg (P < 0.05). Increasing Cu levels, linearly and quadratically (P < 0.001), increased Cu excretion.

Potential of a mixture of eugenol and garlic tincture to improve performance and intestinal health in broilers under necrotic enteritis challenge.

Plant extracts (PE) are gaining increased attention as potential alternatives to in-feed antimicrobials (AM) due to their known antimicrobial activities. This study was conducted to examine the potential of PE, a microencapsulated product composed of eugenol and garlic tincture as an alternative to AM-agent on performance and intestinal health in broilers under necrotic enteritis (NE) challenge. A total of 960 day-old mixed-sex Cobb 500 chicks were randomly distributed to 48-floor pens with 6 treatments replicated 8 times with 20 birds each. The 6 treatments were as follows: UC, unchallenged control; CC, challenged control; PE, challenged group plus PE; AM, challenged group plus AM; FAP, challenged group plus a full dose of AM with PE; HAP, challenged group plus a half dose of AM with PE in starter, grower and finisher phases. Birds in the challenged groups were inoculated with Eimeria spp. on d 9 and Clostridium perfringens on d 14. The body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR), and livability of birds were compromised, and intestinal lesions and mortality were increased (P < 0.05) by NE challenge, illustrating a successful clinical NE challenge. Birds fed AM had higher BWG and FI, and lower FCR, mortality, and intestinal lesions compared to the CC group (P < 0.05). Birds fed PE had improved FCR (P < 0.05) and livability (5.8%) in an overall period compared to the CC group. On d 16, PE supplementation reduced ileal lesion scores in only male birds (P < 0.05). Birds fed PE had decreased Eimeria maxima and Eimeria acervulina oocyst counts in caecal content (P < 0.05). Birds fed PE had decreased Escherichia brunetti and total oocyst counts in caecal content, and E. acervulina oocyst counts in ileal content in only female birds (P < 0.05). On d 35, PE supplementation reduced variation of BW in both male and female birds and increased yellowness (b∗ value, 14.4%) in the thigh. These findings suggest the potential of PE supplementation in diets to improve the performance and intestinal health of birds under clinical NE as indicated by improved FCR, livability, uniformity, reduced ileal lesions, oocyst counts and increased skin yellowness. However, the protective effect of PE may not be apparent in the presence of AM in the feed.

In vitro inhibitory activities of sugarcane extract on avian Eimeria sporozoites.

The current in vitro study aimed to investigate the effects of a processed sugarcane extract on the viability of avian Eimeria sporozoites. Treatments were applied to hatched sporozoites: 1) without additives (no-treatment control); 2) with ethanol; 3) with salinomycin; 4) with Polygain™. All treatments were incubated in RPMI media containing live sporozoites at 37 °C for 14 h and then the number of viable sporozoites were counted. Compared to the no-treatment control, Polygain™ decreased (P < 0.001) the counts of E. maxima, E. acervulina, E. bruneti, and E. mitis sporozoites to a level similar to salinomycin (P > 0.05). In conclusion, Polygain™ could be a potential candidate as an anticoccidial agent.

Monoglyceride Blend Reduces Mortality, Improves Nutrient Digestibility, and Intestinal Health in Broilers Subjected to Clinical Necrotic Enteritis Challenge.

This study evaluated the potential of monoglyceride blend (MG) and buffered formic acid (FA) as alternatives to antibiotics in the performance and intestinal health of broilers under clinical necrotic enteritis (NE) challenge. A total of 544 as-hatched Ross 308 broiler chicks were randomly distributed to 32-floor pens housing 17 birds per pen. The four treatments were: NC-non-additive control; ZBS-antibiotic group supplemented with zinc bacitracin and salinomycin; MG-additive MG supplementation in the starter phase only; and MGFA-additive MG in starter phase and FA in grower and finisher phases. All birds were challenged with Eimeria spp. and Clostridium perfringens. Results showed that the NC group had lower BWG and higher FCR than the ZBS group in the grower and overall period (p < 0.05). The NC group had higher NE-caused mortality (days 14 to 17) than the ZBS group (p < 0.05). Birds fed MG had lower NE-caused mortality than the NC group (p < 0.05). Birds fed MG had upregulated jejunal tight junction protein1 (TJP1) and immunoglobulin (IgG) on day 16 and improved gross energy digestibility on day 24 than the NC group (p < 0.05). These findings suggest that supplementation of MG may improve intestinal health and protect birds from clinical NE occurrence.

Buffered formic acid and a monoglyceride blend coordinately alleviate subclinical necrotic enteritis impact in broiler chickens.

The objective of this study was to evaluate the effect of 2 different doses of a partially buffered formic acid product (Amasil NA; 61% formic acid, 20.5% sodium formate), and a monoglyceride blend of short- and medium-chain fatty acids (BalanGut LS P) on necrotic enteritis (NE) infected broilers in terms of performance, intestinal microbial population and short-chain fatty acids concentrations in the gastrointestinal tract. A total of 528-day-old as hatched Ross 308 broilers were allocated to 48 pens with 11 birds in each pen. Six dietary treatments applied in the study were: T1) nonsupplemented diet (Control); T2) antibiotic supplemented diets; T3) and T4) high (Starter: 0.5%; Grower and Finisher: 0.5%) and low (Starter: 0.3%; Grower and Finisher: 0.2%) dose of Amasil NA; and groups T5) and T6) high (Starter: 0.3%; Grower and Finisher: 0.2%) and low dose (Starter: 0.3%; Grower: 0.15%; Finisher: 0.075%) of (BalanGut LS P). All birds in this study were fed starter (d 0-10), grower (d 11-24) and finisher (d 25-35) diets and challenged with NE. To induce subclinical NE, oral administrations of Eimeria oocysts (d 9) followed by inoculation of Clostridium perfringens strains (d 14 and 15) were applied. Results showed that birds fed the high dose of Amasil NA, had a higher feed conversion ratio (FCR,P < 0.05) compared to the nonsupplemented group during the starter period. Antibiotic supplementation reduced FCR during the grower (P < 0.001), finisher (P < 0.05) and overall (P < 0.001) periods of the experiment. Both levels of BalanGut LS P and low levels of Amasil NA enhanced overall FCR (P < 0.05) compared to the birds in the nonsupplemented group. Compared to the nonsupplemented group, high levels of Amasil NA and low levels of BalanGut LS P improved FCR in the finisher stage (P < 0.05). On d 16, cecum digesta of birds fed with antibiotic supplemented diets showed a significantly lower number of C. perfringens (P < 0.001) compared to the nonsupplemented and high level of BalanGut LS P group. Bacillus (P < 0.01) and Ruminococcus numbers were significantly lower in the birds fed with high level of Amasil NA (P < 0.05) compared to the antibiotic supplemented diets. High doses of Amasil NA, showed the highest propionate concentration in the cecum (P < 0.001). The study suggests that supplementation of BalanGut LS P and Amasil NA at different feeding phases may achieve optimal performance improvement in broilers under NE challenge.

Multi-carbohydrase effects on energy utilization depend on soluble non-starch polysaccharides-to-total non-starch polysaccharides in broiler diets.

Non-starch polysaccharides (NSP), especially in water-soluble form, are a common anti-nutritional factor in cereal-based poultry diets. Consequently, carbohydrases are applied to diets to combat the negative effects of NSP on bird performance and health, particularly when feeding viscous grains. This study investigated the effect of supplementing multi-carbohydrases (MC) to broiler diets containing either low (LS) or high (HS) soluble NSP (sNSP) to total NSP (tNSP) ratios on energy partitioning, nitrogen (N) balance, and performance. A 2 × 2 factorial arrangement of treatments (MC, no or yes; sNSP/tNSP, LS vs. HS) was applied, resulting in 4 dietary treatments, each replicated 8 times. These treatments were fed to Ross 308 broilers in closed-circuit indirect calorimetry chambers, with 2 birds (a male and a female) per replicate chamber (n = 64). The results showed that MC addition increased AME, net energy (NE), and AME/gross energy, regardless of sNSP/tNSP content (P < 0.01 for all). There was an MC × sNSP/tNSP interaction for feed intake (FI, P < 0.05), denoting that in the absence of MC, the HS-fed birds had lower FI than LS-fed birds, but this difference was eliminated when MC was present. There were MC × sNSP/tNSP interactions observed for AME intake (AMEi) per metabolic BW (BW0.70, P < 0.05), AMEi/N retention (Nr, P < 0.01), NE intake (NEi)/Nr (P < 0.05), retained energy (RE) as fat per total RE (REf/RE, P < 0.01), and N efficiency (Nr/N intake, P < 0.05). These interactions showed that MC application increased AMEi/BW0.70, AMEi/Nr, NEi/Nr, and REf/RE only in the HS-fed birds, and N efficiency only in the LS-fed broilers. This study demonstrated that MC application markedly increased feed energy utilization in all diets, and increased N efficiency in birds fed an LS diet.

Influence of trace mineral sources on broiler performance, lymphoid organ weights, apparent digestibility, and bone mineralization.

This experiment was conducted to examine the effect of trace mineral sources on broiler performance, carcass composition, trace mineral digestibility, and tibia bone quality of broiler chickens. A total of 480 Ross 308 male day-old chicks were allocated to 24 pens and assigned to 4 dietary treatments in a completely randomized design. Treatments were as follows: inorganic (I) was basal diet supplemented with 750 g/t inorganic trace mineral premix; organic 1 (O1) and organic 2 (O2) was basal diet supplemented with 375 and 500 g/t organic yeast proteinate trace mineral premix respectively; and hydroxychloride (H) was basal diet supplemented with 1000 g/t salt encrusted trace mineral premix. On day 25, no differences in feed intake (FI), body weight gain (BWG), feed conversion ratio (FCR), or livability (LV) were observed between treatments (P > 0.05). On day 38 birds fed O1 and H had higher weight gain (P < 0.05) and lower FCR (P < 0.001) relative to I. Mineral sources had no impact on FI or LV (P > 0.05) on day 38. Spleen percentage of body weight on day 25 was increased in birds fed O1 and H treatments (P < 0.05) over the I treatment. Mineral sources had no effect on relative weights of thymus or bursa of Fabricius on day 25, or bone quality and carcass composition on day 39 (P > 0.05). Apparent digestibilities of Cu and Zn were greater in birds fed yeast proteinated trace minerals compared to other sources.

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.

BACKGROUND: Measures 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. RESULTS: A 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). CONCLUSION: These 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.

Dietary sugarcane bagasse and coarse particle size of corn are beneficial to performance and gizzard development in broilers fed normal and high sodium diets.

An experiment was conducted to evaluate the effects of sugarcane bagasse (SB) and particle size on broiler performance, gizzard development, ileal microflora, litter quality, and bird welfare under a wet litter challenge model. A total of 672 one-day-old Ross 308 male broilers was allocated to 48 pens using a 2 × 2 × 2 factorial arrangement of treatments with corn particle size-coarse 3,576 µm (CC) or fine 1,113 µm (FC) geometric mean diameter, SB - 0 or 2% and sodium (Na) - 0.16 or 0.40% with increased Na level to induce wet litter. A 3-way particle size × Na × SB interaction (P < 0.05) was observed for weight gain at d 10. Birds fed FC showed a higher weight gain compared to birds fed CC when 0.40% Na without SB diet or 0.16% Na with 2% SB diet was offered. A significant particle size × SB interaction was observed at d 24 on feed conversion ratio (FCR; P < 0.001) and weight gain (P < 0.05). FCR was reduced by 2% SB supplementation in birds fed CC but increased in birds fed FC. Further, weight gain of birds fed 2% SB was higher in birds fed CC but not in those fed FC. On d 35, birds fed 2% SB had a higher weight gain (P < 0.001) compared to those without SB, and a SB × particle size interaction on relative gizzard weight (P < 0.05) and pH (P < 0.05) was present. SB reduced gizzard pH and increased the relative gizzard weight in birds fed the FC diet but not the CC diet (P < 0.05). Counts of ileal Bacillus spp. were increased in birds fed SB (P < 0.05) on d 24. No effects of SB and particle size on litter quality and bird welfare were observed, but higher Na increased litter moisture and footpad dermatitis (FPD) scores (P < 0.001). These findings suggest that SB independently or in combination with CC improves performance in older birds regardless of Na level in diets, possibly through improved gizzard development and gut microflora of birds.

Coarse particle inclusion and lignocellulose-rich fiber addition in feed benefit performance and health of broiler chickens.

Measures to improve gut health and nutrient digestibility have been sought due to in-feed antibiotics being phased out in poultry. The appropriate physical structure of feed ingredients and addition of dietary fiber may be beneficial in enhancing gut health in poultry. In this study, the effect of a lignocellulose-rich fiber source and corn particle size on broiler performance, gizzard development, nutrient digestibility, cecal microflora, and litter quality was evaluated. A total of 684 day-old male Ross 308 chicks were randomly allocated to 6 treatments with 6 replicate pens, each housing 19 birds. A 2 × 3 factorial arrangement of treatments was applied with the factors of: corn particle size (coarse: 2,982 µm or fine: 941 µm geometric mean diameter), and 3 levels of lignocellulose (0%, 1% or 2%). Significant particle size × fiber interaction was observed for feed conversion ratio (FCR) at d 10 (P < 0.05). The birds fed coarsely ground corn (CGC) had lower FCR than those fed finely ground corn (FGC) only at 2% of lignocellulose but not at 1% or no lignocellulose addition. Birds fed FGC were heavier (P < 0.001) at d 10. In contrast, at d 24 and 35, birds fed CGC had lower FCR than those fed FGC (P < 0.05). Ileal gross energy and protein digestibility increased in birds fed CGC compared with those fed FGC at d 24 (P < 0.05). Relative gizzard weight was higher (P < 0.05) on d 24 and 35 in birds fed CGC as compared to those fed FGC. Birds consumed 2% dietary lignocellulose had decreased counts of cecal Clostridium spp. compared to those with 1% lignocellulose (P < 0.05) at d 24. On d 35, both levels of lignocellulose had significantly decreased (P < 0.05) litter moisture content compared to the control. In conclusion, birds fed pelleted diets containing CGC exhibited improved FCR, and increased nutrient digestibility, which may have been caused by larger gizzards. Furthermore, dietary lignocellulose addition is beneficial to litter quality.

Characterisation and quantification of changes in odorants from litter headspace of meat chickens fed diets varying in protein levels and additives.

The effect of dietary crude protein (CP) and additives on odor flux from meat chicken litter was investigated using 180 day-old Ross 308 male chicks randomly allocated to five dietary treatments with three replicates of 12 birds each. A 5 × 3 factorial arrangement of treatments was employed. Factors were: diet (low CP, high CP, high CP+antibiotic, high CP+probiotic, high CP+saponin) and age (15, 29, 35 days). The antibiotic used was Zn bacitracin, the probiotic was a blend of three Bacillus subtilis strains and the saponin came from a blend of Yucca and Quillaja. Odorants were collected from litter headspace with a flux hood and measured using selective ion flow tube mass spectrometry (SIFT-MS). Litter moisture, water activity (Aw), and litter headspace odorant concentrations were correlated. The results showed that low CP group produced lower flux of dimethyl amine, trimethyl amine, H2S, NH3, and phenol in litter compared to high CP group (P < 0.05). Similarly, high CP+probiotic group produced lower flux of H2S (P < 0.05) and high CP+saponin group produced lower flux of trimethylamine and phenol in litter compared to high CP group (P < 0.05). The dietary treatments tended (P = 0.065) to have higher flux of methanethiol in high CP group compared to others. There was a diet × age interaction for litter flux of diacetyl, 3-hydroxy-2-butanone (acetoin), 3-methyl-1-butanol, 3-methylbutanal, ethanethiol, propionic acid, and hexane (P < 0.05). Concentrations of diacetyl, acetoin, propionic acid, and hexane in litter were higher from low CP group compared to all other treatments on d 35 (P < 0.05) but not on d 15 and 29. A high litter moisture increased water activity (P < 0.01) and favored the emissions of methyl mercaptan, hydrogen sulfide, dimethyl sulfide, ammonia, trimethyl amine, phenol, indole, and 3-methylindole over others. Thus, the low CP diet, Bacillus subtilis based probiotic and the blend of Yucca/Quillaja  saponin were effective in reducing the emissions of some key odorants from meat chicken litter.

Dynamics of intestinal metabolites and morphology in response to necrotic enteritis challenge in broiler chickens.

Despite the relatively small contribution to metabolizable energy that volatile fatty acids (VFAs) provide in chickens, these organic acids have been reported to play beneficial roles in the gastrointestinal tract (GIT) of birds, for example, inhibition of the growth of some pathogenic bacteria. However, information regarding the dynamics of these metabolites in the GIT of chickens is still scarce, especially under disease conditions such as necrotic enteritis (NE). Here, we investigated the dynamics of VFAs and lactic acid, and intestinal morphology in response to NE predisposing factors, that is, excessive dietary fishmeal and Eimeria inoculation, and causative agent Clostridium perfringens producing NetB toxin. The experiment was designed in a 2 × 2 × 2 factorial arrangement of treatments with or without: fishmeal feeding, Eimeria inoculation and C. perfringens challenge. The results showed that these factors significantly influenced composition and concentration of VFAs and lactic acids, pH and histomorphometry in one way or another. These changes may be important for the onset of NE or only the synergetic responses to micro environmental stress. Eimeria appeared to be more important than fishmeal in predisposing birds to NE, thus the application of Eimeria in NE challenge provides more consistent success in inducing the disease. The metabolic responses to various adverse factors such as excessive dietary fishmeal and Eimeria infection are complex. Thus, intensive efforts are required to better understand NE so as to achieve the control of the disease in the absence of antibiotics.

Heat Production and Energy Efficiency of Broilers Infected With Necrotic Enteritis.

Necrotic enteritis (NE) in poultry is the most important bacterial disease in terms of economic losses. The present study was conducted to evaluate the effect of an experimental challenge with necrotic enteritis on respiration and heat production in birds pretreated with dietary acylated starch or antibiotics (AB) zinc bacitracin (50 mg/kg) plus salinomycin (60 mg/kg). In total, 48 1-day-old Ross 308 male broilers were assigned to floor pens until day 10. On day 11, birds were randomly placed into 16 calorimetric chambers with four replicates of three birds per treatment. Treatments were: control, AB, acetylated high-amylose maize starch (SA), or butyrylated high-amylose maize starch (SB). Birds were NE challenged by inoculation with 5000 sporulated oocysts each of Eimeria maxima and Eimeria acervulina and 2500 sporulated oocysts of Eimeria brunetti on day 9 and Clostridium perfringens (3.8 × 10(8) colony-forming units) on day 14. The results showed that heat production (HP), respiratory quotient (RQ), heat increment, weight gain (WG), feed intake (FI), and livability (LV) of birds fed control, SA, and SB diets were lower than birds fed AB at 19 and 42 hr postinoculation (P < 0.05). At 65 hr postchallenge, increased FI and WG of birds were observed, indicating recovery from NE. During the entire period, from day 14 to day 17, birds fed control, SA, and SB had lower WG, FI, HP, RQ, metabolizable energy intake (MEI), and metabolizable energy (P < 0.01) than those fed AB. The data demonstrate that Eimeria sp. and C. perfringens challenge reduces growth performance, HP, RQ, metabolizable energy, and MEI of birds fed control, SA, and SB but not AB diets.

Dietary acylated starch improves performance and gut health in necrotic enteritis challenged broilers.

Resistant starch has been reported to act as a protective agent against pathogenic organisms in the gut and to encourage the proliferation of beneficial organisms. This study examined the efficacy of acetylated high amylose maize starch (SA) and butyralated high-amylose maize starch (SB) in reducing the severity of necrotic enteritis (NE) in broilers under experimental challenge. A total of 720 one-day-old male Ross 308 chicks were assigned to 48 floor pens with a 2 × 4 factorial arrangement of treatments. Factors were a) challenge: no or yes; and b) feed additive: control, antibiotics (AB), SA, or SB. Birds were challenged with Eimeria and C. perfringens according to a previously reported protocol. On d 24 and 35, challenged birds had lower (P < 0.001) livability (LV), weight gain (WG), and feed intake (FI) compared to unchallenged birds. Challenged birds fed SA and SB had higher FI and WG at d 24 and 35 (P < 0.05) compared to birds fed the control diet, while being significantly lower than those fed AB. Unchallenged birds fed SA or SB had higher FI at d 24 and 35 compared to those fed the control diet (P < 0.05). Birds fed SB had increased (P < 0.001) jejunal villus height/crypt depth (VH:CD) ratios at d 15, increased ileal (P < 0.001) and caecal (P < 0.001) butyrate levels at d 15 and 24, and decreased (P < 0.01) caecal pH at d 15. Birds fed SA had increased (P < 0.001) ileal acetate content at d 24 and decreased (P < 0.01) caecal pH at d 15. These results demonstrated that dietary acylated starch improved WG in birds challenged with necrotic enteritis. Depending on the acid used, starch acylation also offers a degree of specificity in short chain fatty acid (SCFA) delivery to the lower intestinal tract which improves gut health.

Use of yeast cell wall extract as a tool to reduce the impact of necrotic enteritis in broilers.

The use of a yeast cell wall extract derived from Saccharomyces cerevisiae (Actigen(®)) has been proposed as an alternative to in-feed antibiotics. This experiment was conducted to investigate the efficacy of yeast cell extract as an alternative to zinc bacitracin or salinomycin using a necrotic enteritis challenge model. A feeding study was conducted using 480-day-old male Ross 308 chicks assigned to 48 floor pens. A 2 × 4 factorial arrangement of treatments was employed. The factors were: challenge (- or +) and feed additive (control, zinc bacitracin at 100/50 mg/kg, yeast cell wall extract at 400/800/200 mg/kg, or salinomycin at 60 mg/kg in starter, grower, and finisher, respectively). Diets based on wheat, sorghum, soybean meal, meat and bone meal, and canola meal were formulated according to the Ross 308 nutrient specifications. Birds were challenged using a previously established protocol (attenuated Eimeria spp oocysts) on d 9 and 10(8) to 10(9) Clostridium perfringens (type A strain EHE-NE18) on d 14 and 15). Challenged and unchallenged birds were partitioned to avoid cross contamination. Challenged birds had lower weight gain, feed intake and livability compared to unchallenged birds on d 24 and d 35 (P < 0.05). Birds given zinc bacitracin, yeast cell wall extract, or salinomycin had improved weight gain and livability when compared to control birds given no additives. Challenge × additive interactions were observed for feed intake and weight gain on d 24 and d 35 (P < 0.01). The additives all had a greater positive impact on feed intake, weight gain, and livability in challenged than unchallenged birds. All challenged birds showed higher necrotic enteritis lesion scores in the small intestine sections when compared to unchallenged birds (P < 0.01). Birds fed yeast cell wall extract exhibited increased villus height, decreased crypt depth, and increased villus:crypt ratio when challenged. Yeast cell wall extract, zinc bacitracin, and salinomycin were effective in preventing performance decline from necrotic enteritis in the current study. This study indicates that yeast cell wall extract has promise as a tool for controlling necrotic enteritis.

Evaluation of breed effects on n-3 PUFA metabolism with dietary flaxseed oil supplementation in dogs.

PUFA are important for human and animal health. To our knowledge, previous studies investigating the metabolism of PUFA in dogs have not examined breed differences. The aim of the present study was to evaluate the potential to elongate PUFA in two pure breeds of dogs. Plasma fatty acid composition (%) was measured in dogs during 3 weeks supplementation with flaxseed oil (57 % α-linolenic acid (ALA) and 17 % linolenic acid (LA)) at the rate of 100 ml/kg food following 4 months of feeding an identical standard basal diet. Plasma extracted at fasting state from five beagles and five greyhounds was analysed by GC. Plasma ALA, EPA and LA increased steadily and significantly from days 0 to 22 (P < 0.05); however, no significant breed differences were shown. Plasma DHA levels, on the other hand, showed no significant increase over time, but a significant breed difference was observed, with beagles having higher plasma level from day 0 (P = 0.002). This breed difference requires further investigation. Levels of ALA and EPA were still rising significantly between days 15 and 22, indicating that PUFA levels in plasma had not stabilised in 3 weeks. These findings together suggest that flaxseed oil could be a useful source of PUFA in dogs, especially ALA and EPA, and that breed differences may be important.