Clostridium perfringens causes enteric diseases in animals and humans. In poultry, avian-specific C. perfringens strains cause necrotic enteritis, an economically significant poultry disease that ...costs the global industry over $2 billion annually in losses and control measures. With removal of antibiotic growth promoters in some countries this disease appears to be on the rise. In experimental conditions used to study disease pathogenesis and potential control measures, reproduction of the disease relies on the use of predisposing factors such as Eimeria infection and the use of high protein diets, indicating complex mechanisms involved in the onset of necrotic enteritis. The mechanisms by which the predisposing factors contribute to disease progression are not well understood but it has been suggested that they may cause perturbations in the microbiota within the gastrointestinal tract. We inspected changes in cecal microbiota and short chain fatty acids (SCFA) induced by Eimeria and fishmeal, in birds challenged or not challenged with C. perfringens. C. perfringens challenge in the absence of predisposing factors did not cause significant changes in either the alpha or beta diversity of the microbiota nor in concentrations of SCFA. Moreover, there was no C. perfringens detected in the cecal microbiota 2 days post-challenge without the presence of predisposing factors. In contrast, both fishmeal and Eimeria caused significant changes in microbiota, seen in both alpha and beta diversity and also enabled C. perfringens to establish itself post challenge. Eimeria had its strongest influence on intestinal microbiota and SCFA when combined with fishmeal. Out of 6 SCFAs measured, including butyric acid, none were significantly influenced by C. perfringens, but their levels were strongly modified following the use of both predisposing factors. There was little overlap in the changes caused following Eimeria and fishmeal treatments, possibly indicating multiple routes for progressing towards clinical symptoms of necrotic enteritis.
It is widely established that a high-protein fishmeal supplemented starter diet and Eimeria infection can predispose birds to the development of clinical necrotic enteritis symptoms following ...Clostridium perfringens infection. However, it has not been clearly established what changes these treatments cause to predispose birds to succumb to necrotic enteritis. We analysed caecal microbiota of 4 groups of broilers (n=12) using deep pyrosequencing of 16S rDNA amplicons: (1) control chicks fed a control diet, (2) Eimeria infected chicks fed control diet, (3) chicks fed fishmeal supplemented diet and lastly (4) both fishmeal fed and Eimeria infected chicks. We found that the high-protein fishmeal diet had a strong effect on the intestinal microbiota similar to the previously reported effect of C. perfringens infection. We noted major changes in the prevalence of various lactobacilli while the total culturable Lactobacillus counts remained stable. The Ruminococcaceae, Lachnospiraceae, unknown Clostridiales and Lactobacillaceae families were most affected by fishmeal with increases in a number of operational taxonomic units (OTUs) that had previously been linked to Crohn's disease and reductions in OTUs known to be butyrate producers. Eimeria induced very different changes in microbiota; Ruminococcaceae groups were reduced in number and three unknown Clostridium species were increased in abundance. Additionally, Eimeria did not significantly influence changes in pH, formic, propionic or isobutyric acid while fishmeal induced dramatic changes in all these measures. Both fishmeal feeding and Eimeria infection induced significant changes in the gut microbiota; these changes may play an important role in predisposing birds to necrotic enteritis.
ABSTRACT
Global consumption of chicken meat has increased at a faster rate than any other animal protein source, and thus refinements in energy formulation techniques for feed have continued to gain ...importance. Formulation of animal feed based on net energy (NE) has been implemented in ruminants and pigs but not in poultry. A closed-circuit respiratory calorimetry system was employed on 25- to 28-day-old broilers fed 19 diets formulated with varying nutrient composition to produce equations to predict NE and apparent metabolizable energy (AME) efficiency of feed for broiler chickens. Performance, energy and N balance, respiratory quotient, and energy utilization were measured in the birds. Linear regression analysis was performed to generate prediction equations for dietary energy content and AME efficiency. The NE content was positively related to AME and ether extract, but negatively to crude protein. The study generated equations that can accurately predict NE, and NE/AME using AME value and chemical composition of feeds. The NE prediction equations were further validated on a separate set of diets with high correlation (r = 0.99) and accuracy. The outcomes are an important step for the broiler industry to adapt to an NE system in place of AME systems for the formulation of broiler chicken feeds following robust validation experiments.
Different energy evaluating systems have been used to formulate poultry diets including digestible energy, total digestible nutrients, true metabolizable energy, apparent metabolizable energy (AME), ...and effective energy. The AME values of raw materials are most commonly used to formulate poultry diets. The net energy (NE) system is currently used for pig and cattle diet formulation and there is interest for its application in poultry formulation. Each energy evaluating system has some limitations. The AME system, for example, is dependent on age, species, and feed intake level. The NE system takes AME a step further and incorporates the energy lost as heat when calculating the available energy for the production of meat and eggs. The NE system is, therefore, the most accurate representation of energy available for productive purposes. The NE prediction requires the accurate measurement of the AME value of feed and also an accurate measurement of total and fasting heat production using nutritionally balanced diets. At present, there is limited information on NE values of various ingredients for poultry feed formulation. The aim of this review is to examine poultry feed energy systems with the focus on the NE system and its development for chickens.
ABSTRACT
Feed formulation using apparent metabolizable energy (AME) corrected to zero nitrogen retention (AMEn) is widely used by poultry nutritionists. Most available tabulated data are from ...experiments using adult cockerels or growing broilers. Specific values are rarely available for laying hens. A study was conducted to evaluate AME, AMEn, and AMEs (AME adjusted to 50% nitrogen retention) of corn, soybean meal (SBM) and wheat in laying hens using the reference diet substitution and regression methods. Forty eight 42-wk-old Hy-Line Brown hens were used, 2 birds per cage with six replicates per diet. Test diets contained 30% test ingredient (as is basis) and 65.7% reference diet (as is basis) with limestone, other minerals, vitamins, and amino acids held constant across the reference and test diets. Using the reference diet substitution method, AME values obtained for corn, SBM, and wheat were 3,791, 2,621, and 3,565 kcal/kg (DM), respectively. The corresponding AMEn values were 3,722, 2,496, and 3,479 kcal/kg (DM), and AMEs were 3,784, 2,835, and 3,562 kcal/kg (DM), respectively. Calculation of AME, AMEn, and AMEs of ingredients using regression based on the inclusion rate (DM) of dietary ingredients and reference diet gave identical values to those obtained by the reference diet substitution method. In addition, the measured AMEn values of ingredients using laying hens in this study were close to those calculated from proximate composition using the European Union prediction equation based on adult cockerels.
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.
There is renewed interest in utilizing food waste as animal feed due to its potential benefits in reducing feed cost and environmental impact while improving global food security. This study was ...conducted to examine the efficacy of recycled food waste-based feed for laying hen performance, egg quality, and nutrient digestibility. Hy-Line Brown hens (n = 150) were randomly distributed to three dietary treatments with 50 replicate cages of a single bird per treatment from 24 to 43 weeks of age. The treatments were: a standard/control feed based on wheat, sorghum, and soybean meal; a recycled food waste based-feed; and a 50:50 blend of control and food waste based-feed. Hens offered the food waste-based diets had similar egg weight, hen day egg production, and egg mass, but lower feed intake and higher feed efficiency, compared to those fed the control diets (P < 0.001). Hens fed the food waste diets exhibited lower shell breaking strength and shell thickness at week 34, and higher yolk color score and higher fat digestibility compared to the control treatment at week 43 (P < 0.001). Thus, feeding the recycled food waste based-feed maintained egg production while improving feed efficiency compared to the control feed.
Three experiments were conducted to determine the effect of different dietary net energy (NE) and AMEn ratios (NE:AMEn) on performance, egg quality, and heat production (HP) in laying hens. In ...experiment 1, 62 Hy-Line Brown hens were fed 2 treatments with 31 replicates from 44 to 54 wk of age. In experiment 2, 600 hens of the same strain were fed 3 treatments from 22 to 42 wk of age with 10 replicates. Both used a completely randomized design. Diets were based on corn, wheat, wheat bran, barley, soybean meal, canola meal, meat and bone meal, and canola oil. In both experiments, the NE:AMEn ratio of diets was increased with higher oil inclusion compared with T1 controls. The AMEn (kcal/kg), NE (kcal/kg), ether extract (g/kg), and CP (g/kg), respectively, on a DM basis in experiment 1 was T1: 3,011, 2,288, 42, 202 and T2: 3,023, 2,374, 81, 203; and in experiment 2, T1: 3,026, 2,324, 25, 187; T2: 2,949, 2,315, 61, 185; and T3: 3,026, 2,397, 73, 181. Increasing the ratio of NE:AMEn decreased feed intake (P < 0.001) and increased egg mass (P < 0.05) in experiment 2 and increased egg weight (P < 0.01), decreased feed conversion ratio (P < 0.01), increased egg albumen % (P < 0.001), and decreased yolk % (P < 0.05) and shell % (P < 0.05) compared with T1 controls in both experiments. Haugh units and yolk color scores were increased with high NE:AMEn in both experiments (P < 0.001; P < 0.01). Experiment 3 was conducted in calorimetry chambers to measure HP in birds fed experiment 2 diets. Increasing the NE:AMEn increased total retained energy (RE), RE as fat, and RE in the body (kcal/kg BW0.75/D) and NE:AME. The results indicate that using oil to increase the NE:AMEn results in improved performance and egg quality and more efficient energy utilization.
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.
Poultry production has undergone a substantial increase compared to the livestock industries since 1970. However, the industry worldwide is now facing challenges with the removal of in-feed ...antibiotics completely or gradually, as the once well-controlled poultry diseases have re-emerged to cause tremendous loss of production. Necrotic enteritis (NE) is one of the most important diseases which costs the industry over two billion dollars annually. In this paper, we review the progress on the etiology of NE and its control through dietary modifications, pre- and probiotics, short chain fatty acids, and vaccination. The other likely measures resulted in the most advances in the toxin characterization are also discussed. Vaccine strategies may have greater potential for the control of NE mainly due to clearer etiology of NE having been elucidated in recent years with the identification of necrotic enteritis toxin B-like (NetB) toxin. Therefore, the use of alternatives to in-feed antibiotics with a better understanding of the relationship between nutrition and NE, and limiting exposure to infectious agents through biosecurity and vaccination, might be a tool to reduce the incidence of NE and to improve gut health in the absence of in-feed antibiotics. More importantly, the combinations of different measures may achieve greater protection of birds against the disease. Among all the alternatives investigated, prebiotics, organic acids and vaccination have shown improved gastrointestinal health and thus, have potential for the control of NE.
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